wireless world

Introduction (GPRS)
General Packet Radio Service (GPRS) is a 2.5 generation packet based network technology for GSM networks.

Data Speed
GPRS data speeds are expected to reach theoretical data speeds of up to 171.2 Kbps. However, this is based on optimal conditions in terms of available cell/sector capacity in terms of available time slots, maximum coding scheme (CS-4) as well as moible phone availability to support the maximum number of time slots - eight. More practical data rates are currently in the order of 40-60 Kbps.
3G technologies such as W-CDMA will theoreticaly provide up to 2 Mbps in a fixed location. There will, however, be some significant limitations to this theoretical capacity. While 3G (and beyond) is expected to usher in the advent of high-bandwidth, multi-media services, the real impetus for
2.5G and packet based mobile data lies elsewhere.
Impetus for GPRS
The major impetus for GPRS and other packet based mobile data technologies is the "always-on" capability. Being packet based, GPRS allows for the use of infrastructure and facilities only when a transaction is required, rather than maintaining facilities in a session-like manner. This provides tremendous infrastructure efficiency and service delivery improvements.
Using GPRS as a bearer for WAP, for instance, will allow for the use of WAP on a per-transaction rather than a per-minute-of-use basis. More importantly perhaps is the ability for GPRS to allow for autonomous service realization through the always-on capability. For example, a GPRS customer could receive content or services without actually manually invoking a service or transaction. This has significant implications for mobile commerce and location based services.
GPRS Architecture and Issues
GPRS architecture consists of Gateway GPRS Support Node (GGSN) and a Serving GPRS Support Node (SGSN). The GGSN acts as the gateway to other packet data networks such as the Internet. The SGSN is the serving node that enables virtual connections to the GPRS enabled mobile device and delivery of data.
The blessing and curse of the SGSN is that it supports an attach state when a user is engaged in GPRS data usage and a detach state when idle. The idle state creates a particular challenge for attempting to position the unit for location based services. In addition, GPRS presents a challenge in terms of the ability to offer prepaid mobile data services, which may be overcome by the introduction of CAMEL and perhaps the use of Parlay.
The evolution from GPRS to W-CDMA entails upgrade of the Radio Access Network (RAN) to include two new network elements. The Node B replaces the BTS and the Radio Network Controller (RNC) replaces the BSC in the RAN. However, mobile network operators will maintain their GPRS assets for that service and thus maintain the existing network elements along with the new ones for 3G. W-CDMA continues to use the same Core Network (CN) elements as GPRS.
Deployment and Operational Issues
Beyond the scope of this white paper, there are several significant issues associated with deployment and operation of GPRS systems. Those issues include:
• Capacity and network optimization
• Handset availability and performance
• Quality of service
• Charging for services


Introduction (UUSD)
Unstructured Supplementary Service Data (USSD) is a technology unique to GSM. It is a capability built into the GSM standard for support of transmitting information over the signaling channels of the GSM network. USSD provides session-based communication, enabling a variety of applications.
Technology
USSD is defined within the GSM standard in the documents GSM 02.90 (USSD Stage 1) and GSM 03.90 (USSD Stage 2).
Key attributes:
• USSD is instead session oriented, unlike SMS, which is a store-and-forward, transaction-oriented technology.
• Turnaround response times for interactive applications are shorter for USSD than SMS because of the session-based feature of USSD, and because it is NOT a store and forward service.
• Users do not need to access any particular phone menu to access services with USSD- they can enter the Unstructured Supplementary Services Data (USSD) command direct from the initial mobile phone screen.
• USSD commands are routed back to the home mobile network’s Home Location Register (HLR), allowing for the virtual home environment concept – the ability for services (based on USSD in this case) to work just as well and in exactly the same way when users are roaming.
• Unstructured Supplementary Services Data (USSD) works on all existing GSM mobile phones.
• Both SIM Application Toolkit and the Wireless Application Protocol support USSD.
USSD in Operation
In operation, USSD is used to send text between the user and some application. USSD should be thought of as a trigger rather than an application itself. However, it enables other applications such as prepaid. In operation, it is not possible to bill for USSD directly, but instead bill for the application associated with the use of USSD such as circuit switch data, SMS, or prepaid.

Benefits of USSD
The primary benefit of USSD is that it allows for very fast communication between the user and an application. Most of the applications enabled by USSD are menu based and include services such as mobile prepay and chat.
USSD Enabled Applications
Prepaid Roaming
USSD is used an excellent technology to enable roaming with mobile prepay service. Platform providers such as SICAP offer solutions that involve the use of USSD.
The mobile prepay uses a menu and a USSD connection to indicate the desire to initiate a call while roaming. The MSC connects through to the HLR in the home network (via the SS7 network). The HLR routes the request to the USSD gateway, which in turn routes the request to the prepay application server. The application server checks the balance and provides a call handling instructions response back through the same path to the serving MSC in the visited network. Additionally, a message is sent from a SMSC to the prepay customer, indicating the amount of airtime available on the account.



Chat
Mobile chatting and friend finder applications are another perfect use for USSD as a menu driven application enabling other applications. USSD is the front-end to these types of applications, which require a menu and fast connections for the user interface.
It is important to note that friend finder applications require location determination/management and presence/availability technologies and applications to allow the closed user group to detect if, when, and where members are available. See the Location Based Services paper for more information.

Introduction
CDMA2000's 1xRTT is the first technology for the evolution of cdmaOne 2G networks to 2.5G networks.
GPRS represents the first packet-based technology for evolution from 2G GSM networks to 2.5G networks.
Another GSM 2.5G packet technology, Enhanced Data rates for GSM Evolution (EDGE).
Another 2.5G technology that is circuit based, High Speed Circuit Switched Data (HSCSD).

Impetus for 2.5G
The major impetus for 2.5G is the "always-on" capability. Being packet based, 2.5G technologies allow for the use of infrastructure and facilities only when a transaction is required, rather than maintaining facilities in a session-like manner. This provides tremendous infrastructure efficiency and service delivery improvements.
Using GPRS as a bearer for WAP, for instance, will allow for the use of WAP on a per-transaction rather than a per-minute-of-use basis. More importantly perhaps is the ability for GPRS to allow for autonomous service realization through the always-on capability. For example, a GPRS customer could receive content or services without actually manually invoking a service or transaction. This has significant implications for mobile commerce and location based services.
Data Speed
GPRS data speeds are expected to reach theoretical data speeds of up to 171.2 Kbps. However, this is based on optimal conditions in terms of available cell/sector capacity in terms of available time slots, maximum coding scheme (CS-4) as well as moible phone availability to support the maximum number of time slots - eight. More practical data rates are currently in the order of 40-60 Kbps.
CDMA2000 1xRTT data speeds are averaging about 70-80 Kbps.
EDGE will boost data theoretical data rates to 384 Kbps if/when deployed. EDGE accomplishes these higher rates through introduction of a new modulation scheme known as Eight Phase Shift Keying (8PSK). 8PSK provides for up to 3 bits per symbol (rather than GPRS's 1 bit per symbol), facilitating an up to 3 X's improvement over GPRS.
HSCSD will provide speeds of up to 64 Kbps. However, HSCSD perpetuates the inefficient use of spectrum and transmission that is relegated by any circuit switched mechanism.
Prior to the introduction of these technologies, Cellular Digital Packet Data (CDPD), offered only up to 19.2 kbps on AMPS networks. Other current means of mobile data such as NTT DoCoMo's PDC network offer only 9.6 kpbs, such as used for the highly successful iMode.
3G technologies such as CDMA2000 (1xEV-DO and 3x) and W-CDMA will theoreticaly provide up to 2 Mbps in a fixed location. There will, however, be some significant limitations to this theoretical capacity.
2.5G Architecture and Issues
GPRS represents an overlay network deployment to GSM, thus new network elements are placed into the network while existing network elements, such as the HLR, simply require a software upgrade.
CDMA2000 also represents an overlay network, with 1xRTT first requiring new channel cards, and later versions of CDMA2000 requiring new Core Network (CN) infrastructure such as the AAA server and Packet Data Server Node (PDSN) as part of a Mobile IP network infrastructure.

Introduction (3G)
Third generation (3G) networks were conceived from the Universal MobileTelecommunications Service (UMTS) concept for high speed networks for enabling a variety of data intensive applications. 3G systems consist of the two main standards, CDMA2000 and W-CDMA, as well as other 3G variants such as NTT DoCoMo's Freedom of Mobile Multimedia Access (FOMA) and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) used primarily in China.


Data Speed
The data speed of 3G is determined based on a combination of factors including the chip rate, channel structure, power control, and synchronization.
An example of calculating the theoretical 3G data speed is as follows:
• W-CDMA assigned code 400-500 Kpbs/code. 6 codes X 400 > 2Mbps (UMTS target for 3G data speed in fixed location)
Actual data speeds will vary in accordance with several factors including:
• Number of users in cell/sector
• Distance of user from cell
• User is moving or stationary
• Network operator capacity and network optimization requirements
1xEV-DO is a data-only solution, supporting a theoretical data speed of up to 2.457 Mbps
1xEV-DV is a data and voice solution, supporting a theoretical data speed of up to 3.072 Mbps
FOMA has two operational modes, supporting a dedicated 64 Kbps connection or a 384 Kbps downlink/64 Kbps uplink best-effort connection.
TD-SCDMA can operate in 1.6 MHz or 5 MHz mode for 2 Mbps or 6 Mpbs respectively
Comparison of W-CDMA to CDMA2000
Both use a coding scheme that separates each subscriber from other subscribers
Both use control channels to manage the network
W-CDMA and CDMA2000 are not compatible from the perspective that they have different chip rates - 3.84 MCPS for W-CDMA vs. 1.2888 MCPS for CMDA2000. W-CDMA uses a 5 MHz channel. Initially, CDMA2000 uses only a 1.25 MHz channel, but with CDMA2000 3x, three 1.25 MHz channels can be combined to form a super channel structure.
W-CDMA is synchronous, relying on mobile station time measurements between two base stations, rather than using GPS as CDMA2000 does.
There are three modes of operation for W-CDMA/CDMA2000:
• Direct Sequence (DS) W-CDMA (UMTS) for Frequency Divsion Duplex (FDD)
• W-CDMA Time Division Duplex (TDD)
• CDMA2000 Multi-carrier FDD
Each of the three radio interface methods may be employed on either a GSM or ANSI-based Core Network (CN).
IS-833 is a standard, developed by the 3GPP2, to support CDMA2000 1xRTT Radio Access Network (RAN) to interface with a GSM CN. RAN upgrade required includes CDMA base station and BSC. CN upgrade required includes CDMA PDSN and AAA server.
Impetus for3G
The major impetus for 3G is to provide for faster data speed for data-intensive applications such as video. In addition, 3G to providing faster data speeds on a per-user basis, 3G is also helpful to provide greater overall capacity for voice and data users. For example, NTT DoCoMo's plan to migrate iMode users from the 2G PDC network to FOM is driven by overall capacity concerns, as apposed to individual user data speed requirement.
3G Architecture
W-CDMA uses the same CN as GPRS, utilizing existing infrastruture such as the GGSN and SGSN. W-CDMA, however, does require new RAN infrastructure such as the Node B, which replaces the BTS, and the Radio Network Controller (RNC), which replaces the BSC. Ultimately, the W-CDMA CN will evolve to comprise a full Mobile IP infrastructure including Media Gateway (MGW) and Media Gateway Controller (MGC) equipment for VoIP and other new equipment such as the HSS and CSDF.
CDMA2000 starts with new channel cards and then migrates to a full Mobile IP infrastructure requiring new Core Network (CN) infrastructure such as the AAA server and Packet Data Server Node (PDSN).

Introduction (Advanced messaging)
Advanced messaging technologies will provide advanced capabilities beyond those provided by SMS. In fact, many believe that messaging is the single most important application to exploit the capabilities of 3G (and beyond) networks.


EMS
Enhanced Messaging Services (EMS) – an enhanced version of Short Messaging Service (SMS) is comprised of several text messages that are clustered together. EMS provides capabilities for more rich messaging features such as sending/receiving ring tones and other melodies/sounds, pictures and animations, and modified (formatted) text. Furthermore, all of these could be sent/received as one integrated message for display on an EMS compliant mobile device. EMS is designed to work with any network that already offers SMS using the same store-and-forward infrastructure as SMS. One of the operational issues of EMS is how to bill. Many operators will likely charge for the combined message rather than charge for each individual message comprising the EMS.
EMS is intended to be an evolutionary step towards MMS. However, some believe that EMS will be surpassed as MMS is deployed as an overlay service to SMS.
MMS
Designed for 3G (and beyond) networks, Multi-media Messaging Services (MMS) provides a technical solution of even richer media including text, sounds, images and video to MMS capable handsets. While EMS will perpetuate the rather proprietary architectures and interfaces, MMS will instead be the first mobile messaging service to utilize open Internet standards for messaging. Unlike EMS, which utilizes existing SMS capable terminals, MMS will require new mobile devices. Messaging evolution toward MMS is tightly coupled with and dependent on supporting technologies such as Java, Mobile Station Application Execution Environment
(MexE), and Bluetooth. Other supporting technologies include location based service systems and advanced billing systems.
A key component of MMS is what is referred to as the MMS relay function, which is the conversion of a phone number to an IP address. Unlike with SMS, MMS bearers (such as
GPRS) have an IP address associated with the phone. The MMS relay function allows the sender of a MMS message to address it to the phone number, while the system converts to an IP address for routing to the Multi-media Messaging Service Center (MMSC) and end-user. It is important to note that SMS is "not going away any time soon". In addition to the fact that MMS capable phones must be provided to the end-users, SMS will be used as an alert mechanism - to tell customers that they have some MMS content waiting for them at the MMSC.
Over time, MMS will also need to integrate with unified messaging and communications systems.
Other Messaging Technologies
There are other aspects of advanced messaging, including mobile instant messaging and inter-carrier messaging. Messaging will most certainly evolve to take many forms within mobile communications. One thing is certain to not change - that mobile messaging will remain a value-added service.

Basic Concepts (Billing systems)
Billing systems collect, rate, and calculate charges for use of telecommunications services.
For post-paid services, a collector at the switch gathers data and builds a call detail record (CDR). For prepay systems, prepay processing system determines the appropriate charges and decrements the account accordingly. Both systems utilize a guiding process to match calls to customer’s plans and a rating engine to rate individual calls. In the case of post-paid customers, a CDR is transmitted to a print house to generate a bill, unless Electronic Bill Presentation and Payment (EBPP) systems are used.


Billing vs. Charging
Charging is the process of collecting data to enable monitoring of resource usage, accounting, and/or billing. Billing is the process of processing and rendering a bill.
Settlements
It is important to understand that there is a settlement process that occurs between mobile operators when customers roam from one network to another. This occurs through exchange of CDR data through the use of various roaming clearinghouse companies.
Billing and Charging for Packet Networks
Packet networks such as GPRS have a significant impact as the charging system must be able to handle a much higher number of service events in a given period than voice communications. As applications such as WAP migrate from a monthly fee or time-of-use fee model to a volume fee model, charging systems must evolve to support more frequent data collection.
Significant components for consideration in levying charges in packet networks include:
• Uplink/downlink volume of usage
• Content/services selected
• Quality of service
• Location
Customers vs. Subscribers
Subscribers are distinguished by customers as having pre-subscribed to services (typically meaning there is a permanent record of their account and a billing relationship) as opposed to customers who may be prepay users or have their services paid by some third party, as is expected to be the case in various mobile commerce business models that involve reverse charging scenarios.
Micro-payments
The expectation of various mobile commerce services is that they will entail the use of micro-payments. The notion is that many applications will involve activities such as purchase of refreshment at a vending machine. This is an example of the need to capture charging information, which may be used for inclusion on a bill or rendered to a third party system such as a prepaid account.
SS7 Data Capture
The capture of SS7 data is another significant manner in which to gather charging information. One of the primary purposes for capturing SS7 data is to compare to call detail records. Comparative analysis of data enables the operator to potentially correct errors that may exist in the rating tables of the CDR generator. In addition, SS7 data may be used to audit various relationships such as the charges that are exchanged between operating companies for interconnection.
Introduction (CCP)
Calling Party Pays (CPP) is the arrangement in which the mobile subscriber does not pay for incoming calls. Instead, the calling party pays for those calls. CPP is offered in many places, but has not been regulated in the United States where Mobile Party Pays (MPP) is still predominant.


Issues
There are several issues involving CPP that must be considered. We will briefly discuss three of the biggest issues here.
Notification
There must be some way to notify the calling party that they will have to pay for the call. In Europe and South America, mobile numbers are dedicated to a specific block. This allows the calling party to know when they have called a number for which there will be a different tariff. It is problematic in the US, however, because numbers are allocated to fixed and mobile operators from the same blocks of numbers.
Billing and clearing
: There needs to be a mechanism for billing and clearing between network operators. In most CPP markets, interconnect billing is the rule in which the terminating network is paid a certain amount of monies from the originating network. In contrast, MPP markets utilize a bill and collect mechanism in which the mobile operator expects to be paid directly by the subscriber for minutes of use.
Metered vs. non-metered fixed network calling
In Europe, fixed network callers are accustomed to paying for calls on a metered basis. In the United States, almost all wireline customers have flat-rate service. This creates a natural cognitive barrier to implementing CPP as most US citizens are very unwilling to pay for calls to mobile phones.
Status
While many countries have utilized CPP for some time, the United States has struggled with the CPP issue. In Europe, the percentage of incoming calls to mobile phones is roughly in the range of 45-50% whereas in the US it is about 25-30%. CPP would enable the ratio of incoming to outgoing calls to become more in balance.
In 1997, the FCC initiated actions to investigate the viability of implementing CPP in the US despite the issues of resistance to CPP on the part of fixed network operators who did not want to impose CPP on their customers. Even though CPP could be optional for a mobile customer (to subscriber to CPP as a service), there is still the issue of the need for notification and billing/clearing arrangements that would create the need for further network investment and customer familiarization.
Since the FCC initiative, many opponents to CPP sited that it is not necessary due to various issues. For example, many mobile operators have offered plans in which the first incoming minute is free. In addition, certain mobile operators initiated voluntary CPP plans. However, these plans are limited in service capabilities due to the lack of a comprehensive deployment across networks regarding the notification and billing/clearing issues. Consequently, certain incoming calls would need to be MPP (rather than CPP) such as incoming calls while roaming, calls from other mobile subscribers, and calls from payphones, hotels, and other points of initiation that would difficult to bill and clear.
In the final analysis, the FCC decided to not impose a ruling for CPP. For many opponents to CPP this decision is a victory, claiming that market forces should dictate what is needed. Still proponents of CPP raise the question that CPP would benefit the overall market.


Introduction (EBPP)
Electronic Billing Presentation and Payment (EBPP) is the use of electronic means, such as email or a short message, for rending a bill.

Advantages
The advantage of EBPP over traditional means is primarily the savings to the operator in terms of the cost to produce, distribute, and collect bills.
Use in Mobile Communications
EBPP may be used in lieu of a standard paper bill as a means to reduce operational costs. Some operators may view EBPP as an alternative to prepay as some operators view prepay service strictly as an alternative to traditional billing, but it usually has most value as an alternative mechanism for billing post-paid customers. However, EBPP can also be used simply as an informational tool to inform the customer of charges levied against the account.
Billing and Charging to Third Parties
EBPP is an efficient mechanism to bill or inform third parties of charges. For example, the father of a son in college may want to know how much the child is spending on mobile phone service prior to the bill becoming to high.
Paying the Bill
Some EBPP systems require software for payment while others require only standard browser software for accesses a web site for secure payment. Alternatively, the billing arrangement can be made in advance for funds to be automatically debited from a customer’s account with a financial institution. However, the more attractive model for most will be to have control over when the bill is actually paid, rather than have it be paid at a predetermined date.
Future of EBPP
EBPP is expected to become an increasingly attractive alternative as mobile operators continue to search for ways to reduce operational costs. However, the extent to which EBPP is proliferated will depend entirely on user acceptance and diligence to actually pay for bills in a timely and (preferably) electronic fashion.


Introduction (Government Emergency Telecommunications Service)
The Government Emergency Telecommunications Service (GETS) is an organization established to support the United States National Communications System (NCS). The role of GETS is to provide specialized call processing in the event of congestion and/or outages during an emergency, crisis, or war. GETS has already established capabilities to facilitate priority call treatment for wireline/fixed networks, including the local exchange and long distance networks. In the event of an emergency, the authorities would be able to gain faster access to telecommunications resources than the every-day citizen.


GETS in Fixed Networks
To gain special access privileges, government officials and emergency service personnel would utilize a special universal access number and PIN for authentication. Once authenticated by the network, the calling party would be put into a special priority queue.
During an emergency, normal callers would receive a busy tone, announcement (of all circuits busy), or nothing at all. The special access caller would be placed into a queue until a facility is available. Once a facility is available, the network would utilize ISUP to connect the caller. However, the GETS emergency services implementation of ISUP is different than normal ISUP.
In normal ISUP the network searches facilities end-to-end for total voice trunk availability. This means that voice trunks are reserved along the way, but not seized unless there is at least one available circuit along the entire call path to carry the call. This would not bode well in an emergency, as it would take an inordinate amount of time for an entire call path to become free. Therefore, GETS has implemented a different method.
GETS implementation of ISUP calls for each trunk along a call path to be seized when available. If the entire call path is not available, the system simply seizes a trunk up to a given point. At the last point of seizure, the terminating switch initiates priority queuing once again, starting the process over again. Unless all circuits along a given call path are inoperable or indefinitely held, the caller will eventually be connected from end-to-end reaching the intended call termination point.
GETS in Mobile Networks
This system works well for wireline networks. However, in wireless networks we have the radio interface access port in which to contend. This is an area where mobile IN technologies (WIN/CAMEL) can potentially be of great benefit.
One potential deployment scenario would involve the use of mobile IN to establish a radio port queue.
In this scenario, an MSC equipped with the necessary mobile IN trigger would, upon dialed digit analysis of the special access number and PIN, place an emergency service person in a special queue. The caller would be provided a radio access port as soon as one becomes available. This same queuing process would be utilized to seize a voice channel between the MSC and the PSTN. Once the caller acquires a voice channel and voice circuit to the PSTN, the PSTN switch would recognize the incoming call as a priority call, starting the process described above for wireline calling.
Should the call be destined for another mobile user, the terminating switch could perform similar mobile IN call processing. The terminating call could be placed into queue until a radio channel is available to page the mobile and terminate the call.
It is not known whether GETS will implement a system such as the one described above. This information is provided as an illustration of yet another potentially innovative use of mobile IN for the benefit of mobile users, and in this case, society as a whole.


Introduction
Inter-carrier Messaging (ICM) - sometimes referred to as inter-operator or inter-network messaging - refers to the ability to transmit messages between mobile communications networks regardless of technologies involved (CDMA, GSM, iDen, PDC, or TDMA) and regardless of SMSC protocols deployed (CIMD, SMPP,UCP).

Why is ICM Important?
ICM functionality enables messaging between networks in which otherwise would be constrained to only allow for intra-network messaging between subscribers belonging to the same network. This capability is of particular importance for countries and regions of the world such as the Americas and Asia-Pacific, which contain mobile operators that employ various technologies. ICM enables mobile operators in those areas to enjoy the same benefits of inter-network messaging enjoyed throughout Europe on the homogeneous GSM networks.
How to Deploy ICM
ICM may be deployed by the operator (within its on network) but the more effective solution is to utilize a third-party solution. This is due to economies of scale issues and the administrative impact of provisioning and administration of information, particularly in a country employing mobile number portability. The third-party or service bureau approach is exemplified by leading companies in this area such as the US based Illuminet (www.illuminet.com), a VeriSign (www.verisign.com) company, through their partnership with ICM application provider MobileSpring (www.mobilespring.com).
The basic function of ICM is to first determine the termination network based on evaluation of the destination address of the MDN (ANSI) or MSISDN (GSM), with ancilliary GTT support provided to resolve destination addresses that reside within ported line ranges. Once the termination network is identified, the ICM function performs protocol conversion and reformating of message as necessary.
Important Features of ICM
Along with support for basic SMS feature such as segmentation and concatenation, the successful ICM function must support additional features such as message reply, message confirmation, spam controls, message activity monitoring and reporting capabilities.
The Future of ICM
The future is bright for ICM as wireless carriers in the Americas and Asia Pacific as SMS mobile origination capability is now ubiquitous across all digital networks. The ability for mobile operators to send alpha-numeric text messages amongst themselves will prove crucial in supporting geometric growth curves in messaging as experienced in Europe with GSM. Carriers across international boundries will likely inter-connect to leading service bureau providers of ICM services to enable truly global messaging.
SMS is just the beginning. As mobile networks evolve to support more Advanced Messaging capabilities, end-users will begin to engage in more than merely person-to-person text messaging. Exchange of multi-media information and interactive information and entertainment will become more of the rule than the exception.
Introduction
The Interworking Function (IWF) acts as a gateway between the mobile network and data network infrastructure such as a WAP gateway.


Purpose
The IWF is used to facilitate a circuit switched connection from the MSC to the WAP gateway.
In addition the IWF can be used to support mobile originated and terminated calls for asynchronous data and fax.
The IWF's role is to synchronize events between the circuit-based network and the packet data network.
The IWF is not required for packet based networks such as GPRS
Introduction
Lawful Intercept (LI) or CALEA (Communications Assistance to Law Enforcement Act) represent regulation requiring mobile network operators to enable legally authorized surveillance of communications. This means a "wireless tap" of the communications channel for voice and/or data communications. LI is being considered in Europe and is being mandated in the USA in 2002.


Challenges
Being "unwired", mobile communications is substantively more difficult to tap into than fixed networks. For one, the user may be using service anywhere that the home operator and its roaming partners support service. Consequently, there is a need to determine the presence, identity, and location of callers prior to tapping, as it would otherwise be prohibitively difficult (and a privacy issue) to attempt to tap all calls, merely to filter out those calls that are requiring monitoring by legally authorized personnel.
SS7 networks must be monitored themselves to search for the presence, identity, location, and status of callers. Both call set-up (ISUP) as well as database application (TCAP) components of SS7 networks must be monitored as a means of detecting call placement and/or service or feature interaction. This facilitates a fast set up and operation of a tapping.
Importance of LI
With security being a top priority of government due to terrorist activities, the ability to lawfully monitor communications is of utmost importance to security and law enforcement officials. Other important and related security capabilities include enhanced wireless emergency calling and priority access calling. All of these capabilities are driven by regulatory activities within government.
Technical Issues
There is a need for Administration, Access, Delivery and Collection of Data.
There is a need for Administration in the form of provisioning the tap into the wireless call. This will largely be handled as an administrative function as discussed in the next section.
There is a need for Access in terms of interception of the call and call data. Both call (bearer communications) data and signaling data must be somehow captured. The Delivery function entails capture and conversion of the data into a required legal intercept standard format, which may be delivered to law enforcement monitoring facilities. Collection pertains to monitoring call-identifying (signaling) and call content (bearer) information. The relavent standards include J-STD-025A and ETSI TS 101 671.
More than a Technical Solution Required
A solution is required to mediate the relationship between the requesting agencies (such as the FBI in the US) and the mobile network operators. As many request for LI will undoubtedly result from enforcement of security procedures, there is a need for an intermediary organization or business entity to manage request for intercept and monitoring.

Introduction
The Lightweight Directory Access Protocol (LDAP) is a lightweight version of the Directory Access Protocol, which is part of X.500. Being neither a directory nor a database, LDAP is an access protocol that defines operations for how clients can access and update data in a directory environment.

Why is LDAP Important?
LDAP is used today in many aspects of directory environments involving intranets, extranets, and the Internet. For example, a mobile user may initiate a database lookup over the Internet via WAP to obtain another mobile phone number. This is advantageous in many ways. First, the user’s mobile phone number may only store a certain number of phone numbers. Second, LDAP enables the interface to a directory environment in which the company may update the phone number when it changes. In addition, the requestor may obtain additional information, such as an indication if the owner of the phone number is available or perhaps on holiday.
Directory Enabled Networks
The LDAP is protocol is evolving into a more intelligent network structure called a Directory Enabled Network (DEN). DEN is a network structure that separates the logical properties from physical components. For example, policy elements such as security, quality of service (QoS), and capacity allocation would be separated from the actual policy, application, and directory servers themselves.
Through this separation, the DEN is to achieve several advantages, which include:
• Implementation of policy rules that are logically separated from the specific details of device characteristics and data
• Allow for the network to rapidly reconfigure and self-manage in terms of directory data and network relationships
• Allow the network to recognize people and applications based on pertinent (and potentially dynamically changing) attributes, rather than static data
• Allow for an overall more flexible, less expensive, fully-functional network structure for better support of applications
DENs are separated into two main components: directory and policy servers. A directory is a means of storing and retrieving cross-referenced data. A policy server is provides static and/or dynamically assigned policy management procedures such as QoS or capacity management. Policies can be modified through user intervention or through intelligent agent intervention. Regardless, the DEN enables the policy server to dynamically execute policy in a distributed fashion across the directory network environment.
Summary
LDAP is an important protocol to IP networking and is therefore important to the development and administration of mobile data applications. An important evolution of LDAP will involve the migration to DENs, which have the potential to considerably improve directory environments. However, deployment of DENs, by definition, requires a distributed approach. To gain necessary performance efficiency, it is necessary to cache data in local servers, thus introducing the need for data synchronization.
As mobile Internet connectivity and related applications continue to grow at a rapid pace, the industry will need to introduce DEN and other related technologies to ensure efficient, scalable, fault tolerant database management and operation.
Introduction
In this age of significant telecommunications competition, mobile network operators continuously seek new and innovative ways to create differentiation and increase profits. One of the best ways to do accomplish this is through the delivery of highly personalized services. One of the most powerful ways to personalize mobile services is based on location. We will discuss Location Based Services (LBS), but we will first discuss the basis of LBS - location technology.


Technology
Positioning
One of the most obvious technologies behind LBS is positioning, with the most widely recognized system being the Global Positioning System (GPS). There are however, other means of positioning in addition to GPS. These other technologies are network based positioning and typically rely on various means of triangulation of the signal from cell sites serving a mobile phone. In addition, the serving cell site can be used as a fix for location of the user.
Geographic Information Systems
Geographic data is an important aspect of any location system. Geographic Information Systems (GIS) provide the tools to provision and administer base map data such as man made structures (streets, buildings) and terrain (mountains, rivers). GIS is also used to manage point-of-interest data such as location of gas stations, restaurants, nightclubs, etc. Finally, GIS information also includes information about the radio frequency characteristics of the mobile network. This allows the system to determine the serving cell site of the user.
Location Management Function
It is not enough to be able to position the mobile user and know the map data around that position. There must be a location management function to process positioning and GIS data on behalf of LBS applications. The location management function acts as a gateway and mediator between positioning equipment and LBS infrastructure.
Services
Location based information
Many people are familiar with wireless Internet, but many don't realize the value and potential to make information services highly personalized. One of the best ways to personalize information services is to enable them to be location based. An example would be someone using their Wireless Application Protocol (WAP) based phone to search for a restaurant. The LBS application would interact with other location technology components to determine the user's location and provide a list of restaurants within a certain proximity to the mobile user.
Location based billing
The ability to have preferential billing is provided by this type of application. Through location based billing, the user can establish personal zones such as a home zone or work zone. Through arrangements with the serving wireless carrier, the user could perhaps enjoy flat-rate calling while in the home area and special rates while in other defined zones. This type of application can be especially useful when use in conjunction with other mobile applications such as prepaid wireless.
Emergency services
Hopefully not many readers of this article will have to rely on dialing 9-1-1 from a mobile phone, but if you do, it is a location based emergency service application that pinpoints your location and relays it the appropriate authorities. The FCC has mandated that by October of 2001, all wireless carriers in the United States must provide a certain degree of accuracy in pinpointing the location of mobile users who dial 9-1-1.
Tracking
This is a rather large category that contains everything from the difficult fleet applications to enabling mobile commerce. Fleet applications typically entail tracking vehicles for purposes of the owning company knowing the whereabouts of the vehicle and/or operator. Tracking is also an enable of mobile commerce services. A mobile user could be tracking and provided information that he has predetermined he desires, such as notification of a sale on men's suits at a store close to the user's current proximity.
Summary
Location is a strategic asset of wireless carriers. Leveraging this information enables the user to experience value-added services and the mobile network operator to offer differentiation and incremental profitability. See the book Wireless Intelligent Networking for more information about the technology behind LBS and applications.


Introduction (Mobile basics)
This module provides a brief introduction to the basic concepts and technologies associated with mobile communications.

Wireless vs. Mobile Communications
Wireless telecommunications can be divided into two broad categories: mobile communications and fixed wireless communications. Each category has its own unique market in terms of customer needs and technology requirements. The mobile communications market requires mobility or non-tethered communications.
The goal of mobility is anytime, anywhere communications. Mobile communications technology must be able to allow roaming - the ability to provide service to a mobile phone users while outside their home system. On the other hand, fixed wireless is simply an alternative to wired communications. The fixed wireless user does not need mobility. Instead, the fixed wireless user needs cost effective telecommunications from fixed locations. Wireless is an alternative means of providing service. It is sometimes the only means. When the customer is in a remote location, satellite is the only alternative.
Cellular and PCS
The personal communications concept arose after cellular networks were deployed. Personal Communications Service (PCS) technologies were designed to meet the needs of anytime, anywhere personalized communications. PCS networks were deployed utilizing cellular RF designs similar to cellular. However, many PCS carriers initially deployed larger groupings of smaller cell sites to cover densely populated urban areas. PCS also uses a higher portion of the RF spectrum (1900 MHz in the US versus 800 MHz for cellular). Being deployed after the initial cellular networks, PCS networks also initially had more advanced technologies than PCS, including SS7 network infrastructure for services such as calling number identification. However, cellular would soon catch up due to competitive pressures. In aggregate, there are now no substantive differences between the initial "cellular" networks and "PCS". In fact, they both utilize the same underlying technologies.
Mobile Communications Protocols
Radio Frequency Protocols
Interim Standard 136 (IS-136) is a specific Time Division Multiple Access (TDMA) based radio frequency (RF) standard.
IS-95 is a specific Code Division Multiple Access (CDMA) based radio frequency (RF) standard. With TDMA, multiplexing occurs within time slots within dedicated frequency band for each call or data session. On the other hand, CDMA is a "spread spectrum technology", utilizing all available frequency and time slots within an allocated service band.
It is important to be aware that TDMA and CDMA are digital RF protocols. There are various analog RF protocols that are still in commercial service, but they are being replaced with TDMA and CDMA as mobile operators upgrade their networks.
Mobile Networking Protocols
IS-136 and IS-95 based networks both utilize ANSI-41 as a protocol for mobile networking. ANSI-41 based networks are deployed primarily in the Americas and parts of Asia.
Global System for Mobility (GSM) is a global standard based on TDMA. GSM utilizes the GSM Mobile Application Part (MAP) as a mobile networking protocol.
Mobile Networking
Cellular/PCS networks can use different type of mobile networking protocols that allow for roaming – the use of a mobile phone while away from the home area – and advanced services.
Global System for Mobility (GSM) networks deployed in Europe and throughout the world utilizes a protocol called the GSM Mobile Application Part (MAP), standardized by the European Telecommunications Standards Institute (ETSI). Other TDMA based networks and CDMA networks utilize a protocol called ANSI-41, a protocol standardized by the Telecommunications Industry Association (TIA) and the American Standards Institute (ANSI).
Mobile networking entails communication between Home Location Registers (HLR) and Visiting Location Registers (VLR) - databases used to store information about subscribers. Communication between these databases allows roaming.
ANSI-41 and GSM MAP
GSM MAP and ANSI-41 are key protocols that utilize SS7 to allow roaming and advanced as well as more advanced capabilities. Communication between the VLR in the serving system and the HLR of the home area is facilitated by these mobile networking protocols and signaling based on a signaling protocol called Signaling System number Seven (SS7).
In GSM networks, the MAP rides on top of SS7, allowing VLR to HLR (and HLR to VLR) communications.
In non-GSM networks (such as many of those found in the United States), ANSI-41 is deployed (which also uses SS7) for HLR/VLR communications.
Mobile IN for GSM & ANSI-41
While there are various proprietary-based mobile intelligent network (IN) technologies, the standards based technologies are often of most value to the mobile network operator and their customers. These standards based technologies are referred to as Customized Applications for Mobile Enhanced Logic (CAMEL) and Wireless Intelligent Network (WIN) and are used in GSM and ANSI-41 based networks respectively.

Introduction
Simply put, Mobile Instant Messaging (MIM) is the ability to engage in IM from a mobile handset via various bearer technologies, which may include SMS, WAP, or GPRS.




IM in the Fixed Environment
IM in the fixed environment is perhaps best exemplified by the likes of AOL, Microsoft, and Yahoo, which each have a large base of IM users that typically use IM on a fixed client, such as a laptop computer. Fixed IM includes a rich User Interface (UI) experience and high bandwidth.
Characteristics of MIM
In a mobile environment, the user is constrained by bandwidth and the UI. However, the user has the advantage of mobility. MIM users will desire to message with other MIM users as well as fixed IM users on networks such as AOL, Microsoft and Yahoo. MIM allows users to address messages to other users (via various bearers) using an alias (or user name) and address book, allowing the sender to know when his/her "buddies" are available.
SMS versus MIM
SMS is a bearer that can be used for MIM. By itself, SMS does not include alias capabilities nor does it allow for confirmation that the intended recipient is available. Being transaction based (rather than session based), plain SMS (without MIM) does not allow the send to have a high degree of confidence that the recipient will receive the message in real-time. MIM allows the community of users to register as being presence and/or available, allowing for more real-time text messaging and communications than would be possible with traditional mobile messaging.
Future of MIM
Future MIM systems will be much more robust and pervasive, encompassing more valuable functionality and including interoperability between IM systems.
Rich and Robust Presence
Future MIM systems will likely include rich and robust
Presence and Location Based Services capabilities, which will enhance the system to be able to detect the presence, availability, and/or location of fellow MIM users.
Interoperability and Inter-carrier Messaging
Future MIM systems will likely leverage network mediation to enable messaging between MIM and fixed IM systems. This will be the key for much more wide scale adoption and usage.


Introduction
This module provides a brief introduction to the concepts and technologies associated with intelligent networks for mobile communications. Mobile IN capabilities are becoming increasing important as mobile network operators strive to deploy advanced value-added services to their customers.


IN Concepts
All intelligent networking for telecommunications involves the concept of a "query/response" system. This system entails the notion of distributed intelligence wherein a database is queried for information necessary for call processing. For example, a mobile communication switch or Mobile Switching Center (MSC), that is equipped with mobile IN call logic, can launch a message or "query" to a database hosted by a network element called a Service Control Point (SCP). The SCP processes the request and issues a "response" to the MSC so that it may continue call processing as appropriate.
Wireless intelligent networking is more complex than fixed network based intelligent networking due to the dynamic nature of mobile communications and thus the need for mobility management.
As the world evolves to embrace Internet protocol (IP) technologies, the notion of "network intelligence" is also evolving. The need to leverage IN to support convergence of traditional circuit switched with packet-based networks grows daily.
SS7
SS7 is a critical component of modern telecommunications systems. SS7 is a communications protocol that provides signaling and control for various network services and capabilities. While the Internet, wireless data, and related technology have captured the attention of millions, many forget or don't realize the importance of SS7. Every call in every network is dependent on SS7. Likewise, every mobile phone user is dependent on SS7 to allow inter-network roaming. SS7 is also the "glue" that sticks together circuit switched (traditional) networks with Internet protocol based networks.
SS7 Architecture
SS7 is comprised of a series of interconnected network elements such as switches, databases, and routing nodes. Each of these elements is interconnected with links, each of which has a specific purpose. The routing nodes are the heart of the SS7 network and are called a Signal Transfer Point (STP). STPs are connected to Service Switching Points (SSP) that are switches equipped with SS7 control logic. SSP switches are connected to the STPs via Access links (A links). STPs also connect to databases called Service Control Points (SCP) via A links. The SCP is the network element that contains service control logic such as instructions for converting an 8XX (toll-free) number into a routable number.
WIN, INAP, and CAMEL
Wireless Intelligent Network (WIN), Intelligent Network Application Part (INAP), and Customized Applications for Mobile Enhanced Logic (CAMEL) mobile IN technologies all have their origin in the same Intelligent Network Conceptual Model (INCM). However, WIN is the standard for ANSI-41 based networks, CAMEL is the standard for GSM based networks, and INAP is actually a European fixed network standard for which many vendors have created proprietary extensions to enable service delivery capabilities.
Capabilities
The reasons for deploying mobile IN technologies are to provide value-added capabilities for purposes such as cost reduction, improved service delivery, increased variety and quality of services, and rapid service creation and deployment.
These capabilities rely on underlying mobile networking technologies to handle mobility management functions. Together with mobile networking, mobile IN capabilities allow the mobile network operator to deploy a variety of advanced and/or value-added applications.
Applications
Mobile IN enables value-added applications such as:
• One number service
• Prepaid service
• Location based services
• Call management services
• FreePhone (toll-free calling)


Introduction
Mobile IP is the underlying technology for support of various mobile data and wireless networking applications. For example, GPRS depends on mobile IP to enable the relay of messages to a GPRS phone via the SGSN from the GGSN without the sending needing to know the serving node IP address.

The Impetus for Mobile IP
With the advent of packet based mobile data applications and the increase of wireless computing, there is a corresponding need for the ability for seamless communication between the mobile node device and the packet data network (PDN) such as the Internet.
Mobile IP Definitions
Mobile Node: A device capable of performing network roaming
Home Agent: A router on the home network which serves as the a point for communications with the mobile node.
Foreign Agent: A router that functions as the mobile node's point of attachment when it travels to the foreign network.
Care of Address: Termination point of the tunnel toward the mobile node when it is not in the home network.
Correspondent Node: The device that the mobile node is communicating with such as a web server
Mobile IP in Operation
To accomplish this, mobile IP established the visited network as a foreign node and the home network as the home node. Mobile IP uses a tunneling protocol to allow messages from the PDN to be directed to the mobile node's IP address. This is accomplished by way of routing messages to the foreign node for delivery via tunneling the original IP address inside a packet destined for the temporary IP address assigned to the mobile node by the foreign node. The Home Agent and Foreign Agent continuously advertise their services on the network through an Agent Discovery process, enabling the Home Agent to recognize when a new Foreign Agent is aquired and allowing the Mobile Node to register a new Care of Address.
This method allows for seamless communications between the mobile node and applications residing on the PDN, allowing for seamless, always-on connectivity for mobile data applications and wireless computing.
Mobile IP enabled Applications
Mobile IP technology is embedded in the functionality of packet equipment for 2.5G and 3G. In addition, mobile IP enables advanced applications such as unified messaging.


What is a MVNO?
For more information, see: http://www.mobilein.com/MVNO/

A Mobile Virtual Network Operator (MVNO) is a mobile operator that does not own its own spectrum and usually does not have its own network infrastructure. Instead, MVNO's have business arrangements with traditional mobile operators to buy minutes of use (MOU) for sale to their own customers.

Distinguishing Characteristics of the MVNO
Many are familiar with simple resellers of telecom services such as long distance, local exchange, and mobile network services. In contrast, MVNO's typically add value such as brand appeal, distribution channels, and other affinities to the resale of mobile services.
Successful MVNO's are those that position their operations so that customers do not distinguish any significant differences in service or network performance yet offer some special affinity to their customers. Unlike simple resellers, who often have little or no brand recognition, MVNO's are typically well known, well positioned companies, with a good deal of marketing clout. For example, Virgin Atlantic Airlines is a MVNO in the UK that uses its market recognition to position itself for selling directly to its airline customers and others.
Successful MVNO's will also be those that have ample financial resources and sufficient agreements with existing operators to provide a good service coverage area. Additionally, well-diversified independent MVNO's can offer a product mix that incumbent mobile operators can not match. For example, grocery store MVNO's could offer a package of MOU's and groceries.
Operational Issues
While MVNO's typically do not have their own infrastructure, some leading providers are actually deploying their own Mobile Switching Centers (MSC) and even Service Control Points (SCP) in some cases. Leading MVNO's deploy their own mobile IN infrastructure in order to facilitate the means to offer value-added services. In this way, MNVO's can treat incumbent infrastructure such as radio equipment as a commodity, while the MVNO offers its own advanced and differentiated services based on exploitation of their own intelligent network infrastructure. The goal of offering value-added services is to differentiate versus the incumbent mobile operator, allowing for customer acquisition and preventing the MVNO from needing to compete on the basis of price alone.
MVNO's have full control over the SIM card, branding, marketing, billing, and customer care operations. While sometimes offering operational support systems (OSS) and business support systems (BSS) to support the MVNO, the incumbent mobile operators most keep their own OSS/BSS processes and procedures separate and distinct from those of the MVNO.
Business Issues
The major benefit to traditional mobile operators cooperating with MVNO's is to broaden the customer base (sell additional MOU's) at a zero cost of acquisition.
It is likely that incumbent mobile operators will continue to embrace MVNO's as a means of deriving revenue to offset the enormous cost of building 3G networks.
As more MNVO's expand in the marketplace, they are likely to first target prepaid customers as a means of low cost market entry themselves.
Most regulating bodies are in favor of MVNO's as a means of encouraging competition, which would ultimately lead to greater choice and lower prices.
With the advent of the MVNO, many incumbent mobile operators will evaluate the opportunity to offer supplementary MVNO services of their own. To do so, exiting mobile operators will use their established branding, service knowledge, and supplier relationships to complete against independent MVNO's.
United States MVNO's (as of August 2006)

9278 Mobile
Airlink Mobile
Airvoice Wireless
Amp'd Mobile
Apple Mobile
Beyond Wireless
Boost Mobile
Bratz Mobile
Bravo Cellular
Cbeyond
Circle K
Consumer Cellular
cool.Prepaid
Cricket
DBS Communications
DEXA Wireless
Disney Mobile
Embarq
Firefly Mobile
Flying J
GlobalTalk PCS
Graffiti Wireless
GTC Wireless
HELIO
JitterBug


Jump Mobile
kajeet
MobileESPN
Movida
Nexus Mobile
nTelos
Omni Prepaid
Page Plus Cellular
PlatinumTel
Primus Wireless
Qwest Wireless
Revol Wireless
Speak Out Wireless
Sprint Nextel Cable JV
STi Mobile
Total Call Mobile
TracFone
TuYo Mobile
Virgin Mobile USA
Voce
Wal-Mart
Working Assets Wireless
XE Mobile
XERO Mobile
Xtreme Mobile






Introduction
Personal Area Networks (PAN) are formed by wireless communications between devices by way of technologies such as Bluetooth and UWB. PAN standards are embodied by the IEEE 802.15 family of "Home Wireless" standards, which superseded older infrared standards and HomeRF for dominance in this area of wireless communications.


Applications
Like all personalization technologies, PAN applications are virtually limitless. However, a key capability for a PAN is to enable devices to autonomously detect and acquire one another. This provides the ability for personalization through unconscious communications. For example, a PAN in ones automobile would provide various telematics applications, such as the ability for the system to detect the presence of the user, thereby allowing the mobile handset to automatically acquire pertinent information for driving such as weather and road conditions.
One of the fundamental advantages of PANs is that they negate the need for wires, allowing the user to, for example, have a wireless headset, create ad hoc connections to
Other applications include mobile commerce in which user of a mobile device communicates with another machine for commerce such as ticket purchase, vending and other small purchases.
The evolution of PANs will be from man-to-man, man-to-machine, and finally machine-to-machine.
Issues and Challenges with PANs
The biggest initial issue will simply be to equip devices with software to enable the PAN connection. This will occur once technology such as Bluetooth is cost effective and available in large quantities for deployment.
One of the biggest issues with PANs is the ability for devices to inter-operate with one another. This is not so much an issue with pre-established networks of devices, which all have the same vendor equipment, but it is a major issue for inter-vendor equipment connections. This is a major factor for unconscious communications. Companies are working to solve these issues with various equipment mediation and interoperability software.
Ad hoc vs. Unconscious Communications
Ad hoc connections are simply those that occur in an automatic fashion, but the user is engaged in some activity in which it is known that a connection is about to occur. Examples include connecting to a LAN or buying a beverage from a vending machine.
On the other hand, unconscious communications occur as a result of automatic connections that made between devices unbeknownst to the user. Examples include a user coming home and the local base station in the home sensing this event and thus messaging to the network to treat all calls as home zone calls rather than mobile calls in the macro network. Unconscious connections are the real end-goal for many applications that involve personalization and mobile commerce. The real issue will be to solve the interoperability problems between differing vendor provided equipment.
PAN Standards
• 802.15.1a: Bluetooth (2.4GHz at 1Mbps)
• 802.15.2: Coexistence of PANs with one another
• 802.15.3: High rate PAN (2.4GHz at 55 Mbps)
• 802.15.3a: Alternative high rate PAN for UWB (2.4GHz at 110 Mbps)
• 802.15.4: Low rate PAN - Zigbee
• 802.15.4a: Alternative low rate - low power UWB
Introduction
Smart cards in the wireless marketplace provide: improved network security through user identification, a facility for storing user data, and a mechanism for recording various service data events. These capabilities enable improved service customization and portability in a secure environment, especially suited for various transaction based services.
Smart cards are tamper resistant and utilize ISO-standardized Application Protocol Data Units (APDU) to communicate with host devices via PIN codes and cryptographic keys.
This paper provides an overview of various smart card technologies and business issues.

Types of Smart Cards
Contact Cards and Contactless Cards
Contact Cards require insertion into a smart card reader with a direct connection to a conductive micro-module on the surface of the card.
Contactless Cards require only close proximity (a few inches) of a reader.
Categories of Smart Cards
• Integrated Circuit (IC) Microprocessor Cards: Allow for adding, deleting, or manipulating information in memory, allowing for a variety of applications and dynamic read/write capabilities. Most Smart Cards in use for mobile applications are of this type.
• IC Memory Cards: Can store data, but do not have a processor on the card.
• Optical Memory Cards: Can only store data, but have a larger memory capacity than IC memory cards.
Smart Card Standards
ISO 7816 is the international standard for Smart Cards.
SIM
The introduction of smart cards for wireless communications occurred in the early 1990’s when GSM networks deployed the Subscriber Identity Module (SIM) – a security module initially deployed to provide a facility for challenge/response authentication for GSM subscribers.
SIM hardware consists of a microprocessor, ROM, persistent EEPROM memory, volatile RAM, and a serial I/O interface. SIM software usually consists of an operating system, file system, and application programs. As with all smart cards, the SIM relies on the card terminal – the GSM handset – for battery and clock.
STK
The SIM evolved to incorporate the use of the SIM Toolkit (STK) - an important API for securely loading applications to the SIM. STK allows the mobile operator to create/provision services by loading them into the SIM without changing anything in the GSM handset. One convenient way for loading applications to the SIM is over-the-air via Short Message Service (SMS). Once loaded, applications on the SIM can be activated via various event triggers registered by the application at the STK. Occurrences such as an incoming/outgoing call or SMS message, call duration, and/or location of the mobile can all act as triggers. Control software with the SIM monitors such events and reports activities via SMS to a network based application server. This facilitates an excellent systems for smart card based value-added services such as mobile prepay and location based services.
Java Card
The Java card sits on top of the smart card OS, allowing application programmers access for deployment of services independent of the hardware and OS of the smart card. Executable code is platform independent, meaning that any card incorporating a Java Card interpreter can run the same application. When coupled with the STK, the Java card allows services to load and run on cards from different vendors.
UIM
Introduced by the CDMA Development Group and the 3GPP2, the Removable User Identity Module (R-UIM) card represents a smart card for use with CDMA based mobile phones.
WIM
Introduced with WAP specification 1.2, the WAP Identification Module (WIM) provides end-to-end security for WAP, improving on version 1.1 which only provided transport security between the handset and the WAP gateway.
S@T
The SIM Alliance has proposed a SIM Alliance Toolkit (S@T) as an industry standard for WAP based services for via any GSM phase 2+ phone that is not WAP enabled. The SIM Alliances states that one of the key benefits of S@T is the availability of WAP based services to non-WAP phones. Furthermore, all WAP browsers earlier than version 1.2 do not support WIM, making S@T and an enabler of secure transactions thanks to the SIM.
Smart Card Applications for Mobile Networks
Alphacard.com: Custom ID bages & id card software
Smart Cards may be used for a variety of applications such as financial services and mobile prepay. Ability for them to store personal user-related information allows them to be used for key data such as personal preferences, health history, and financial information such as account balances. The ability to dynamically update the information is a key attribute.


Introduction
Short Message Service (SMS) is a mobile data service that allows alphanumeric messaging between mobile phones and other equipment such as voice mail systems and email.


Technology
SMS is a store-and-forward system. Messages are sent to a Short Message Service Center (SMSC) from various devices such as another mobile phone or via email. The SMSC interacts with the mobile network to determine the availability of a user and the user's location to receive a short message.
Because SMS uses the control channel (rather than the voice channel), a unique feature of SMS is that the user can receive a SMS whether or not a call is in progress - the phone need only be turned on. If the phone is not turned on, the SMSC will wait until the phone is turned on to send the message. A "message received" is sent to the SMSC from the MSC upon delivery to the mobile device, allowing the SMSC to provide confirmation of receipt to the sender upon request.
One of the issues with SMS is interoperability between different technologies such as CDMA and GSM. To accomplish messaging between these different technologies, Inter-carrier Messaging technology must be deployed to provide for messaging between mobile operators with different technologies.
Business Issues
SMS first appeared in GSM in about 1991. SMS later appeared in CDMA and TDMA networks. Mobile Origination (MO) - a key feature of SMS, allowing the user to originate SMS messages from the handset - has only became available to non-GSM users in 2000.
SMS has become a key service for mobile operators, generating tremendous usage, particularly among the youth market segment. With the advent of technologies such as WAP and the introduction of GPRS and 3G, some question the future of SMS. It is clear, however, that SMS will have a long life as a low-bandwidth messaging service, available on all types of phones.
Benefits of SMS
SMS increases the amount of voice calling by providing a mechanism for voice mail notification to the handset.
SMS provides a convenient, low-cost mechanism for non-voice communication.
SMS provides a mechanism for enabling various other applications such as prepaid.
SMS Enabled Applications
SMS can be used for a variety of uses in conjunction with mobile prepay including notification of low balance and balance inquiry, short codes used in conjunction with prepaid roaming, and even SMS itself can be provided on a prepaid basis by the mobile network operator.
When used in conjunction with the SIM Toolkit, SMS can be used as the vehicle for a variety of secure transaction-oriented services such as mobile banking.
Introduction
SS7 is a critical component of modern telecommunications systems. SS7 is a communications protocol that provides signaling and control for various network services and capabilities. While the Internet, wireless data, and related technology have captured the attention of millions, many forget or don't realize the importance of SS7. Every call in every network is dependent on SS7. Likewise, every mobile phone user is dependent on SS7 to allow inter-network roaming. SS7 is also the "glue" that sticks together circuit switched (traditional) networks with Internet protocol based networks.

SS7 Technology
SS7 signaling is a form of packet switching. Unlike circuit switching, which utilizes dedicated data "pipes" for transmission of information, packet switching dynamically assigns "routes" based on availability and "least cost" algorithms. Another example of packet switching is TCP/IP, the protocol used for routing messages over the Internet. Unlike the Internet, which utilizes a vast public "web" of interconnecting facilities and routing equipment, SS7 networks are private and logically self-contained. The private nature of SS7 networks is critical for security and reliability.
SS7 involves two different types of signaling: connection oriented signaling and connectionless oriented signaling. Connection oriented signaling refers to the establishment of switch-to-switch facilities call inter-office trunks. These trunks carrier voice communications. The ISDN User Part (ISUP) part of the SS7 protocol is utilized to establish trunks between switches. In contrast, the Transaction Capability Application Part (TCAP) is utilized for connectionless signaling which typically entails switch-to-database or database-to-database communications. An example of connectionless signaling is TCAP signaling of HLR to VLR communications discussed in the mobile networking article.
SS7 Networks
SS7 is comprised of a series of interconnected network elements such as switches, databases, and routing nodes. Each of these elements is interconnected with links, each of which has a specific purpose. The routing nodes are the heart of the SS7 network and are called a Signal Transfer Point (STP). STPs are connected to Service Switching Points (SSP) that are switches equipped with SS7 control logic. SSP switches are connected to the STPs via Access links (A links). STPs also connect to databases called Service Control Points (SCP) via A links. The SCP is the network element that contains service control logic such as instructions for converting a 8XX (toll-free) number into a routable number.
STPs are always deployed in pairs, allowing a spare should one of the STPs have a problem. Each STP of a "mated pair" are connected to each other via Cross links (C links). STP pairs connect to other STP pairs via Bridge or Diagonal links (B or D links). B links connect STP pairs that are at the same level of hierarchy while D links connect STP pairs that are different hierarchial levels. An example would be STPs in a local network connecting with STPs of a long distance network. Being at different hierarchies, the local-to-long distance links would be considered D links.
Links used for SS7 communication directly between SSPs (no STP involved) are called Fully associated links (F links). An example of these links are those that are used in combination with voice trunks between two mobile network SSPs. The F link is used to signal a hand-off message from one SSP to the other, allowing the mobile phone user to travel from one area (served by one switch) to another area (served by another switch).
Extended links (E links) are used to connect an SSP to an alternative STP pair. In the event that the primary STP pair is inoperable, the alternative pair establishes operations with the SSP over the E links.
Business Issues
In today's modern telecommunications networks, SS7 is used for virtually every call to establish a voice connection between the calling and called party locations. SS7 is also the medium for advanced capabilities and applications including mobile networking and services as well as wireline applications such as toll-free calling and automatic calling card identification.


Introduction
Careful planning and engineering of SS7 networks is crucial for efficient and effective operation of modern telecommunictions networks.

SS7 Links
SS7 messages are carried by a physical medium referred to as a link. While there is some variation throughout the world, the traditional facility type utilized for an SS7 link is a 64 kbps circuit outside the US and a DS-0 circuit, with a load carrying capacity of 56 kbps within the US.
SS7 Nodes
A Service Switching Point (SSP) is a telecommunications switch that contains the control logic (software) necessary to send/receive SS7 messages to other nodes in the network. SSPs are able to send/receive IN messages (ANSI-41/WIN, INAP, and CAMEL) over the TCAP portion of the SS7 protocol.
Signal Transfer Points (STP) are provided in "mated pairs" and operate in what is called "load sharing mode", meaning that, at any given time, each STP should be processing 40% of the total signal-processing load. In the event of a STP and/or link(s) failure, the network is designed to changeover to the remaining STP so that it can process at 80% load.
Like STPs, Service Control Points (SCP) are (almost always) deployed in a mated pair configuration. This designed redundancy makes allowance for a back-up SCP should the other go out of service for some reason.

Planning and Engineering
SS7 networks are designed for extremely high reliability and to survive any sort of disaster. To accomplish this design goal, SS7 networks have built-in fault prevention and isolation technologies. In addition, SS7 network nodes and links are deployed in a geographically diverse manner for survivability in the event of a disaster or equipment/facility isolation event.
SS7 networks have various capacity-limiting elements including processing capacity, disc space, table size for translations, input/output capability, and other resources. All of these components must be considered in engineering a node. The most limiting capacity element at any given time must be used in network capacity planning.
Traffic engineering of SS7 networks involves defining calls/data use cases, defining SS7 message attributes, gathering data and/or estimating demand, computing capacity requirements, determining the amount of calls/sessions that may be handled based on capacity demands and assumptions, monitoring growth of traffic demands, and planning for capacity exhaust.
SS7 network nodes and links are engineered to allow for adequate capacity so that a failure in any one component will not prevent the remaining components from handling the entire remaining load. Therefore, STPs, SCPs, and links are often engineered at 40% capacity, allowing for the remaining node/links to carry 80% of the load (the other 20% is for traffic "peakedness") in the event of a node or link failure.
Ongoing planning and management of SS7 networks requires network monitoring, capture of usage information, and projection of SS7 signaling requirements based on anticipated introduction and usage of various features.
Planning of large SS7 networks also requires consideration of network topology and the size and routing of messages. For example, it does not always make the most sense to directly connect a SSP to the closest STP pair. The SSP may have most of its SS7 traffic (and/or data size of messages) with a SCP that is located at a distant side of the overall SS7 network. Therefore, it may be more economically sound to connect the SSP to a STP closer to the SCP pair in question, even if that connection would incur additional facilities costs, those costs may be off-set by reducing the capacity demand on the SS7 backbone.


Introduction
Wireless Application Protocol (WAP) is an enabling technology based on the Internet client server architecture model, for transmission and presentation of information from the World Wide Web (WWW) and other applications utilizing the Internet Protocol (IP) to a mobile phone or other wireless terminal.


Formation of WAP
Ericsson, Motorola, Nokia, and Phone.com founded the WAP Forum in June 1997 to create license-free standards for the entire industry to use to develop products based on WAP.
WAP Protocol Stack
From top to bottom, the WAP protocol stack consists of the following:
• Application layer
• Session layer
• Transaction layer
• Security layer
• Transport layer
• Network layer
Deployment and Operation of WAP
Unlike iMode, WAP requires a gateway to convert between WAP's native language, Wireless Markup Language (WML), and HTML for operation between mobile networks and the WWW.
WAP can be deployed using circuit switch or packet switch bearer facilities such as GPRS. The advantages of packet based WAP include faster speed and always-on capabilities.
WAP and Roaming
When initiating a WAP session while roaming, a connection is made between the visited network and the WAP gateway in the home network. While this provides for basic WAP services to the roamer as if he was in the home network, mobile IN technologies such as CAMEL are required to truly provide a virtual home environment.
WAP and Prepay
While WAP can be provided on a prepay basis with certain prepay techniques such as hot-billing, prepay WAP will benefit significantly better from the implementation of CAMEL phase 3 in conjunction with GPRS as a bearer.
Evolution of WAP
While early implementations of WAP have been relatively unimpressive from a user experience, WAP is poised to leverage packet data networks, push based services, color and animation on the handset, and value-added services such as location based services.


Introduction
This paper compares and contrasts, Wireless Application Protocol (WAP), a protocol used to provide mobile data services, and iMode, a complete mobile Internet service. The purpose of this paper is to briefly discuss some of the technical differences between WAP and iMode rather than commercial aspects of either technology.


Architecture
WAP uses a special language called Wireless Markup Language (WML) for communication between a special protocol conversion device called a WAP Gateway (GW) and content on the Internet. The WAP GW converts between WML and HTML, allowing delivery of WAP based content to a WAP capable mobile device.
In most network today, the connection between the MSC and the GW is circuit switched as indicated in the illustration above in which the MSC must utilize the Public Switched Telecommunications Network (PSTN) to connect to the GW. As mobile network operators deploy next generation packet-data technologies such as General Packet Radio Service (GPRS), the connection between the MSC and the WAP GW will be upgraded to leverage the faster packet connection facilitated by the GPRS network.
In contrast to WAP, iMode utilizes an overlay packet network for direct communications (no gateway needed) to the content providers on the Internet.
Protocols
While WAP uses WML, iMode uses a derivation of HTML called compact HTML (c-HTML). Being a sub-set of HTML, c-HTML is easier to learn and apply than WML.
It is likely that both WAP and iMode will evolve at some point to incorporate XML.
Device Capabilities
WAP devices must support a WAP browser whereas iMode capable devices must be able to display information from c-HTML.
WAP devices display only text information whereas iMode devices display multi-color images.
WAP supports navigation between layered menus whereas iMode supports navigation through hyperlinks.
Summary
While WAP and iMode have technical differences, they must support the same market for mobile data services.
Introduction
Wireless Emergency Services (WES) refers to the use of mobile positioning technology to pinpoint mobile users for purposes of providing enhanced wireless emergency dispatch services (including fire, ambulance, and police) to mobile phone users.
While WES is a type of location-based service (LBS), it is a mandate in the United States where 911 is the official dialing pattern for fixed and mobile network access to emergency services.

US Mandate for WES
In October 1994, the Federal Communications Commission (FCC) issued FCC 94-102, with the order published in July 1996. The original order required:
• By 1st October, 1997: Phase 0 required all 911 calls to be delivered to Public Safety Answer Points (PSAP), even for unintialized mobile devices
• By 1st April, 1998: Phase I required mobile operators to provide a call back number and location data to PSAP
• By 1st October, 2001: Phase II required mobile operator to provide call back number and caller location within 125 meters 67% of the time based on a root mean square (RMS*) average
The FCC later amended the location accuracy/precision requirements for phase II to the following:
• Handset based position determination equipment (PDE): 50 meters 67% of the time, 150 meters 95% of the time
• Network based PDE: 100 meters 67% of the time, 300 meters 95% of the time
• Hybrid PDE: 50 meters 67% of the time, 150 meters 95% of the time
The above requirements provide for the ability to phase in the required technology over a four year period.
The FCC recognized the fact that, generally speaking, handset based PDE (such as A-GPS) is more accurate than network based PDE. The FCC also recognizes that it will take some time for mobile operators to deploy handsets for handset based positioning. Specific accuracy obtained will be dependent on the type of mobile positioning deployed and other factors such as environmental conditions such as user distance from the location measurement units, topography, and atmospheric conditions.
Technology for US WES
In order to deploy WES in the US, mobile operators need the following:
• PDE
• Wireless 911 application
• Location manager middle-ware application
• Coordination with PSAPs regarding locations/routing to emergency service jurisdictions
WES Standards
The TIA Ad Hoc Emergency Services (AHES) committee developed a standard, which would eventually become a joint standard for US ANSI-41 and GSM deployments of WES - the J-STD-036. The J-STD-036 ultimately evolved to incorporate a mobile positioning center (MPC) that would provide the location manager middle-ware function for WES as well as commercial based LBS. Additional Wireless Intelligent Network (WIN) standards are evolving to provide additional capabilities in support of the MPC and commercial LBS.
Europe Initiative for WES
The European Commission established the Coordination Group on Access to Location Information by Emergency Services (CGALIES) with the mission to define requirements for a Pan European common location provisioning mechanism, that can be accessed and used by the European 112 community and emergency service operators. The plan is to have a system in place by 2003.
While Europe will likely use US implementations, network architecture, and standards as guide, it is probable that there will be certain differences. However, the same core technologies such as SS7 and location middle-ware shall be the same.


Introduction (Wireless Testing)
The complexity of wireless networks will increase more quickly in the next five years than it did in the previous fifteen due to the rapid advent of broadband service. These networks will need to quickly move from supporting voice-centric to implementing data-intensive applications. This urgency comes from the need to defray the steep entry costs paid by wireless operators worldwide. The progression from fixed desktop applications to mobile office with hand-held devices requires a far more robust and flexible network, with richer content, than simple circuit switching technology permits. To be useful and profitable, the content provided by these connections will need to be timely, topical and customized to the needs of the user. Customers will demand always-on connections, ready at a moment’s notice. As these new networks integrate third-generation (3G) technologies, they will increasingly migrate toward data-optimized, packet-switched topologies from current voice-optimized network design.

Previous technologies for test access in wireless networks are proving to be insufficient for the widely-distributed, heavily-loaded, mission-critical networks toward which wireless carriers are evolving. The days of telecom testers laboriously searching through equipment racks for test ports, while network downtime mounts, have changed. Customer expectations of higher quality service mandate a stronger focus on testing and service assurance, as well as proactive monitoring programs to track network performance and resolve network problems before they become network outages.
Deployment of a Network Test Access (NTA) system maximizes the ROI on planned 3G networks by ensuring more cost-effective and efficient test access and service. At the same time, NTA solutions reduce costs associated with maintaining and upgrading legacy networks.
The need for test access in wireless 3G
Designing test access into emerging 3G networks represents the best way to ensure rapid deployment, minimize incident response time and gain efficiency in testing. As wireless networks evolve into multi-vendor, super-regional entities, new testing methods must be used to ensure standards compliance, network performance and uninterrupted service. The service demands of 3G networks include more sophisticated content, more demanding users and, ultimately, fulfillment of service level agreements (SLAs), which have become common in non-wireless networks. To support these goals, a test access approach must make test equipment deployment:
-easy for any authorized user to access
-comprehensive, to meet all testing needs
-secure, to ensure control of the test environment
-vendor-independent, to ensure that any type of hardware or software can be used for testing
-technology-agnostic, to assure common procedures are used in whatever type of network is deployed
-scalable, to ensure response levels as the network grows in scope as well as speed
-rapid, to maximize responsiveness and minimize downtime
By designing test access into its 3G network architecture, a network operator carrier can ensure that efficient testing and trouble resolution will be provided during evaluation, optimization and at launch. Furthermore, by considering NTA at the time the network is defined, testing can be automated and included in legacy OSS (Operational Support System) implementations. This inclusion allows network operation centers to gracefully incorporate the new networks into their operations, minimizing training requirements and allowing broader testing availability. Finally, including NTA in the initial design of a network, or network expansion, eliminates service interruptions, which may be caused by retrofitting test access into a live network.
Benefits of centralized network testing
As networks grow more complex and expand geographically, the value of centralizing testing has become evident. In a geographically compact network, moving test equipment and test expertise to the relevant network link is an easy task. However, as networks become more widespread or complex, this task becomes more difficult, time consuming and error prone, relying on both tester proximity and equipment availability. Designing NTA into the network architecture allows remote deployment of both equipment and testers, enabling rapid resolution of testing issues and network problems. For example, data applications have a high incidence of transient problems that may disappear by the time local testing is performed. Through extremely rapid test deployment, NTAS reduces "no trouble found" occurrences. This rapid response, combined with effective action, results in increased network uptime. As performance improves, it becomes practical to address requests for Service Level Agreements in a carrier’s standard service offering.
Remote test access can have the further benefit of providing a testing solution that is not tied to any specific technology, vendor or method. Carriers can use whatever type of test equipment that meets their needs and budget while maintaining the ability to easily incorporate new testing equipment or hierarchies as needs change. Software programs can even mask the different technologies used within the network, leading to shorter learning curves for testers and greater productivity from all testing resources. NTA fits within most standard OSS (Operational Support System) models, and allows extension of the efficiencies and control gained by an OSS into more areas of the network.
NTA provides a more efficient use of test equipment because individual test equipment can be leveraged across an entire section of the network. This ensures test equipment is always available when and where needed and eliminates delays due to transport or field usage. The number of testers with access to each device can be increased, allowing immediate test activities of network segments from a remote location. Furthermore, when test equipment is available and accessible, testers are free to use test equipment throughout the network for proactive monitoring.
The need for fast and efficient test access is documented by the Gartner Group, which in 2000 predicted that during the 2000-2005 period , spending on the network infrastructure and buildout will grow at 2 to 3 times the rate of spending on personnel managing the network
. Streamlining operations through an NTAS solution directly improves the ability of network administrators and testers to manage the network, and, therefore, lower costs. Conclusion
As new 3G networks are proposed and constructed, the complexities associated with managing wireless networks increases. Recognizing the need for Network Test Access (NTA) solutions will result in lower maintenance costs and increased network uptime by providing a means for improved network management through efficient and effective test deployment, even from remote locations. Inclusion of NTA during the planning phase of network deployment eliminates issues associated with retrofitting and allows "first minute" monitoring of the network. Customers’ increased demands for service quality will be effectively met with a test access system that supports proactive monitoring and rapid response to network issues for a maximum ROI.



Introduction
Wireless Local Area Networks (WLAN) are increasing becoming an attractive alternative to licensed spectrum. Initially thought of strictly as a competitor to 3G, WLAN is now thought of as a complement to cellular based data services, providing a high bandwidth alternative to 3G at a fraction of the cost.

Public Access WLAN
Being that WLAN’s are only available through limited access points referred to as hot spots, it is important to recognize that WLAN service does not allow for truly ubiquitous service. Public Access WLAN requires deployment of certain network capabilities including access control, authentication, authorization, and usage accounting. In addition, clearing and settlement among businesses in the value chain is required, as access point providers, serving networks, and home networks all need to be paid appropriately. Only through the implementation of these capabilities may a service provider effectively provide WLAN roaming to it customers.

Billing

One of the key aspects of providing public WLAN is to offer comprehensive billing services. Many services only offer the ability to charge to one's credit card. As services evolve, the need to offer billing to one's cellular service provider bill or other billing alternative will become increasingly important.

Clearing and Settlement

The ability to settle payments among providers of service across the entire Public Access WLAN value chain is critical to offer WLAN roaming service, as each party must be paid there due or roaming would not be allowed to occur.
3G and WLAN
One of the more important issues associated with WLAN roaming is the ability to allow roaming between 3G and WLAN services. This is a key capability to allow for a seamless service experience between all the (licensed and unlicensed spectrum based) services that a mobile network operator may offer.
WLAN roaming may utilize some of the same GRX-type infrastructure (such as AAA servers) as used for GPRS or 1xRTT roaming, thus providing synergies and economies of scale and scope to common service providers.
Seamless Service Handover
As public service further evolves, increasingly more wireles devices will include smart client software that automatically detects available spectrum and switches over to the best available or per the user preference, allowing for a seamless experience - no break in service.
WLAN Roaming and Service Bureaus

All of the aforementioned support services are arguably best provided by some sort of a service bureau, outsourced offering on behalf of members of the Public Access Wireless LAN value chain.

Summary

Public Access Wireless LAN has begun the life cycle as basically a service island, just as cellular once did before roaming. As the service evolves roaming will be critically important for basic services as well as various WLAN-based applications.

Over time, the tradional use of WLAN (laptop use) will be eclipsed by the use of many WLAN equipped devices such as PDA's, providing a truely pervasive always connected community of users.
Introduction
XML provides a manner in which meta-data - data about information - can be represented in a structured format. Being a text based language, XML is very easy for a human to read and understand the data and structure.
XML and Markup Languages
Being a markup language based on SGML (Standard Generalized Markup Language), extensible markup language (XML) provides a mechanism to identify and present structured information. Unlike hypertext markup language (HTML), XML does not define tag semantics. For example, in HTML,

is always a first level heading and
means a break in the representation of displayed information. Instead, XML is actually a meta-language for describing markup languages, providing a facility to define tags and the structural relationships between them. There is therefore no predefined tag set or semantics. Instead, all semantics of an XML document are defined by applications that process them or by stylesheets.
XML Goals
• Provide a common communications structure for media-independent communications across systems
• Allow industries to define platform-independent protocols for data exchange
• Allow for the flexible display of information
• Keep the number of optional XML features to a minimum so as to reduce the potential for compatibility problems
XML Structure and Processing of Information
XML uses start and end tags such as and to mark up information. Information marked by tags is referred to as an element. Name-value pairs called attributes may further define elements. For example, zone="postal code" indicates that a zone being defined in the XML data structure is a postal code versus any other type of zone, such as a city zone.
XML must be parsed into usable information. An XML parser will
XML makes use of something called a document type definition (DTD), which identifies markup data delineated (by paragraphs, topic headings, etc.) and how each and how they are to be processed. A XML DTD reader at the receiving end of an XML message will be able to process the data and display the information as intended. XML is used to transport data in a text format. In order to display information to the user interface, XML data must be converted into some other format such as scalable vector graphics (SVG).
Scalable Vector Graphics
Scalable Vector Graphics (SVG) is a language for describing two-dimensional graphics in XML, which supports vector graph shapes (straight lines and curves), images, and text. In addition to being a web-based standard for graphics display, SVG is also an efficient at displaying information. SVG is a more efficient approach than bitmap formats such as GIF or JPEG, which must contain information on every single pixel needed to display an image, making files big, slow, and static, with no interactivity.
Extended Links and Extended Pointers
Extended Links (XLink) allow for the expression of relationships between two or more resources. Extended Pointers (XPointer) provide a method of locating resources within a body of data, without the need for that resource being identified with an ID attribute.