Standardization

Standardization of telecommunications technologies and associated service enablers is of key importance for the development of communicating systems in a multi-vendor environment. Many parties such as operators, manufacturers, third party application developers, and sometimes regulators collaborate in the scope of standardization activities to produce technical specifications that are widely endorsed for the development of commercial solutions.

• Third Generation Partnership Project (3GPP): 3GPP is not a standardization development organization in its own right but rather a joint project between several regional standardization bodies from Europe, North America, Korea, Japan, and China. The prime objective of 3GPP is to develop UMTS technical specifications. It is also responsible for maintaining existing GSM specifications and developing further GSM extensions (e.g., GPRS).
• Third Generation Partnership Project 2 (3GPP2): 3GPP2 is another standardization partnership project established out of the International Telecommunication Union’s (ITU) International Mobile Telecommunications ‘‘IMT-2000’’ initiative. The role of 3GPP2 is to produce specifications for services deployed in several North American and Asian markets with focus on next generation CDMA networks.
• GSM Association (GSMA): GSMA is a global trade organization that represents the interest of several hundreds of GSM mobile operators.
• Internet Engineering Task Force (IETF): IETF is a large community of academic and industrial contributors that defines the protocols primarily used on the Internet. Messaging services in the mobile world also rely on several IETF protocols.
• World Wide Web Consortium (W3C): W3C is a standardization body that concentrates on the development of protocols and formats to be used in the World Wide Web. Well-known formats and protocols published by W3C are the Hypertext Transfer Protocol (HTTP) and the eXtensible Markup Language (XML).
• WAP Forum: the Wireless Application Protocol (WAP) Forum was a joint project for the definition of WAP technical specifications. WAP Forum: the Wireless Application Protocol (WAP) Forum was a joint project for the definition of WAP technical specifications.
• Open Mobile Alliance (OMA): OMA is a standardization forum established in June 2002. Activities of several existing standardization bodies including the ones of the WAP Forum (MMS and others) have been transferred to OMA. OMA is therefore actively involved in maintaining MMS standards designed by the WAP Forum and producing new standards for next generations of MMS devices.

Wireless Application Protocol

The Wireless Application Protocol (WAP) is the result of a collaborative work between many wireless industry players, carried out in the scope of the WAP Forum. The forum, launched in 1997 by Nokia, Phone.Com (now Openwave), Motorola, and Ericsson produced technical specifications enabling the support of applications over various wireless platforms (GSM, GPRS, UMTS, etc.).

Introduction to WAP
The WAP technology is an enabler for building applications (e.g., browsing, messaging, etc.) that run seamlessly over various wireless platforms. focus on the following aspects:
• Interoperability: applications developed by various parties and hosted on devices, produced by different manufacturers, interoperate in a satisfactory manner.
• Scalability: mobile network operators are able to scale services to subscribers’ needs.
• Efficiency: the framework offers a quality of service suited to the capabilities of underlying wireless networks.
• Reliability: the framework represents a stable platform for deploying services.
• Security: the framework ensures that user data can be safely transmitted over a serving mobile network, which may not always be the home network. This includes the protection of services and devices and the confidentiality of subscriber data.
In line with these considerations, the WAP technology provides an application model close to the World Wide Web model. The web model includes the following key elements:
• Standard naming model: objects available over the web are uniquely identified by Uniform Resource Identifiers (URIs).
• Content type: objects available on the web are typed. Consequently, web browsers can correctly determine the type of a specific content.
• Standard content format: web browsers support a number of standard content formats such as the HyperText Markup Language (HTML).
• Standard content format: web browsers support a number of standard content formats such as the HyperText Markup Language (HTML).
the web model, as it is, does not efficiently cope with constraints of today’s mobile networks and devices. To cope with these constraints, the WAP model leverages the web model by adding the following improvements:
• The push technology allows content to be pushed directly from the server to the mobile device without any prior explicit request from the user.
• The adaptation of content to the capabilities of WAP devices relies on a mechanism known as the User Agent Profile (UAProf).
• The support of advanced telephony features by applications, such as the handling of calls (establishment and release of calls, placing a call on hold, or redirecting the call to another user, etc.).
• The External Functionality Interface (EFI ) allows ‘‘plug-in’’ modules to be added to browsers and applications hosted in WAP devices in order to increase their overall capabilities.
• The persistent storage allows users to organize, access, store, and retrieve content from/to remote locations.
• The Multimedia Messaging Service (MMS) is a significant added value of the WAP model over the web model. It relies on generic WAP mechanisms such as the push technology and the UAProf to offer a sophisticated multimedia messaging service to mobile users.

The WAP model uses the standard naming model and content types defined in the web model. In addition, the WAP model includes the following:
• Standard content formats: browsers in the WAP environment, known as microbrowsers, support a number of standard content formats/languages including the Wireless Markup Language (WML) and the eXtensible HTML (XHTML). WML and XHTML are both applications of the eXtensible Markup Language (XML).
• Standard protocols: microbrowsers communicate according to protocols that have been optimized for mobile networks, including the Wireless Session Protocol (WSP) and HTTP from the web model.

WAP Architecture
The WAP device can communicate with remote servers directly or via a number of intermediary proxies and gateways. The primary function of proxies/gateways is to optimize the transport of content from servers to WAP devices.

Push Technology
With push technology, a server is able to push some data to the WAP device with no prior explicit request from the client. In the push framework, the push initiator initiates the push transaction. The push initiator, usually an application server (e.g., web server, MMS center, etc.) transmits the content to be pushed along with XML-formatted delivery instructions to a Push Proxy Gateway (PPG).
The PPG then delivers the push content to the WAP device. The push initiator interacts with the PPG using the Push Access Protocol (PAP). On the other side, the PPG uses the Push Over The Air (OTA) protocol (based on WSP or HTTP) to deliver the push content to the WAP device.

User Agent Profile
The objective of this specification is to define a method for describing the capabilities of clients and the preferences of subscribers. For this purpose, the user agent profile is formatted using a Resource Description Framework (RDF) schema in accordance with Composite Capability/Preference Profiles (CC/PP).
UAProf is composed of the following components:
• Hardware platform: this component gathers a set of properties indicating the hardware capabilities of a device (screen size, etc.).
• Software platform: this component groups a set of properties indicating the software capabilities of a device (operating system, supported image formats, etc.).
• Browser user agent: this component gathers properties characterizing the Internet Browser capabilities.
• Network characteristics: this component informs on network and environment Characteristics such as the bearer capacity.
• WAP characteristics: this component advertises WAP browsing capabilities of the device. This includes information on the configuration of the WML browser and so on.
• Push characteristics: this component indicates push capabilities of the device. This includes the set of supported content types, the maximum message size that can be handled, and whether or not the device can buffer push messages.
• MMS characteristics: this component describes the device capabilities for retrieving and rendering multimedia messages (MMS version, maximum message size, supported content types, etc.).

Universal Mobile Telecommunications System

UMTS aims at providing services such as web browsing, messaging, mobile commerce, videoconferencing, and other services to be developed according to emerging subscribers’ needs with the following objectives:
• high transmission rates encompassing circuit-switched and packet-switched connections;
• high spectral efficiency and overall cost improvement
• definition of common radio interfaces for multiple environments
• Portability of services in various environments (indoor, outdoor, suburban, urban, rural, pedestrian, vehicular, satellite, etc.). This service portability is also known as the Virtual Home Environment concept.

3G Services
The UMTS Forum classifies 3G services into the following six groups as illustrated:
1- Mobile Internet access: a mobile access to the Internet with service quality close to the one offered by fixed Internet Service Providers. This includes full Web access, file transfer, electronic mail, and streaming video and audio.
2- Mobile Intranet/Extranet access: a secure framework for accessing corporate Local Area Networks (LANs) and Virtual Private Networks (VPNs).
3- Customized infotainment: a device-independent access to personalized content from mobile portals.
4- Multimedia messaging service: a means of exchanging messages containing multimedia contents including text, images, and video and audio elements.
5- Location-based services: location-aware services such as vehicle tracking, local advertisements, etc.
6- Rich voice and simple voice: real-time, two-way voice communications. This includes Voice over IP (VoIP), voice-activated network access, and Internet-initiated voice calls.

First Phase UMTS
The UMTS architecture [3GPP-23.101] has to meet the requirements of various UMTS services.

First Phase UMTS Architecture
The first phase UMTS architecture is based on evolved GSM and GPRS core networks and a specifically tailored Universal Terrestrial Radio Access Network (UTRAN).

User Equipment
The UE, usually provided to the subscriber in the form of a handset, is itself composed of a Mobile Equipment (ME) and a UMTS Subscriber Identity Module (USIM).
The 3GPP classifies multi-mode UEs into the following four categories:
• Type 1: type 1 user equipment operates in one single mode at a time (GSM or UTRA). It cannot operate in more than one mode at a time.
• Type 2: while operating in one mode, type 2 user equipment can scan for and monitor another mode of operation.
• Type 3: type 3 user equipment differs from type 2 user equipment by the fact that the type 3 UE can receive more than one mode at a time. However, a type 3 UE cannot emit simultaneously in more than one mode.
• Type 4: type 4 user equipment can receive and transmit simultaneously in more than one mode. Switching from one mode to another is performed automatically.

UTRA Network
The UTRAN is composed of nodes B and Radio Network Controllers (RNCs). The node B is responsible for the transmission of information in one or more cells, to and from UEs. It also participates partly in the system resource management. The node B interconnects with the RNC via the Iub interface. The RNC controls resources in the system and interfaces the core network.

First Phase UMTS Core Network
The first phase UMTS core network is based on an evolved GSM network subsystem (circuit-switched domain) and a GPRS core network (packet-switched domain).

Second Phase UMTS
The objective of this initial architecture is to allow mobile network operators to rapidly roll out UMTS networks on the basis of existing GSM and GPRS networks. From this first phase UMTS architecture, the next phase is to evolve to architecture with a core network based on an enhanced packet-switched domain only. The objective is to allow a better convergence with the Internet by using IP-based protocols whenever possible.

General Packet Radio Service

The General Packet Radio Service (GPRS) is an extension of GSM which allows subscribers to send and receive data over packet-switched connections. The use of GPRS is particularly appropriate for applications with the following characteristics:
• bursty transmission (for which the time between successive transmissions greatly exceeds the average transfer delay);
• frequent transmission of small volumes of data;
• infrequent transmission of large volumes of data.

GPRS Architecture
A GPRS mobile station is categorized according to its capabilities to support simultaneous modes of operation for GSM and GPRS [3GPP-22.060] which are as follows:
• Class A: the mobile station supports simultaneous use of GSM and GPRS services (attachment, activation, monitoring, transmission, etc.). A class A mobile station may establish or receive calls on the two services simultaneously. The high complexity of designing class A devices makes them prohibitively expensive to produce and, therefore, these devices are typically not available for the mass market.
• Class B: the mobile station is attached to both GSM and GPRS services. However, the mobile station can only operate in one of the two services at a time.
• Class C: the mobile station is attached to either the GSM service or the GPRS service but is not attached to both services at the same time. Prior to establishing or receiving a call on one of the two services, the mobile station has to be explicitly attached to the desired service.
Before a mobile station can access GPRS services, it must execute a GPRS attachment procedure to indicate its presence to the network. After its GPRS attachment, the mobile station activates a Packet Data Protocol (PDP) context with the network in order to be able to transmit or receive data. This procedure is called PDP context activation.

Serving GPRS Support Node
The Serving GPRS Support Node (SGSN) is connected to one or more base station subsystems. It operates as a router for data packets for all mobile stations present in a given geographical area. It also keeps track of the location of mobile stations and performs security functions and access control.

Gateway GPRS Support Node
The Gateway GPRS Support Node (GGSN) provides the point of attachment between the GPRS domain and other data networks such as the Internet or corporate networks. An Access Point Name (APN) is used by the mobile user to establish the connection to the required destination network.

Global System for Mobile Communication

Mobile networks implemented in different countries were usually incompatible. This incompatibility made impracticable the roaming of mobile users across international borders. In order to get around this system incompatibility, the Confe´rence Europe´enne des Postes et Te´le´communications (CEPT) created the Groupe Spe´cial Mobile1 committee in 1982. In 1989, the European Telecommunications Standard Institute (ETSI) took over the responsibility for the maintenance and evolution of GSM specifications. In 2000, this responsibility was transferred to 3GPP. With GSM, the transfer of data can be carried out over circuit-switched

GSM Architecture
The GSM network is composed of three subsystems: the Base Station Subsystem (BSS), the Network Subsystem (NSS), and the Operation Subsystem (OSS).

Mobile Station
The Mobile Station (MS) is a device that transmits and receives radio signals within a cell site. The mobile station is composed of the Mobile Equipment (ME) and the Subscriber Identity Module (SIM). The unique International Mobile Equipment Identity (IMEI) stored in the ME identifies uniquely the device when attached to the mobile network.



Base Transceiver Station
The Base Transceiver Station (BTS) implements the air communications interface with all active MSs located under its coverage area (cell site). This includes signal modulation/demodulation, signal equalizing, and error coding. Several BTSs are connected to a single Base Station Controller (BSC).

Base Station Controller
The BSC supplies a set of functions for managing connections of BTSs under its control. Functions enable operations such as handover, cell site configuration, management of radio resources, and tuning of BTS radio frequency power levels. In addition, the BSC realizes a first concentration of circuits towards the MSC. In a typical GSM network, the BSC controls over 70 BTSs.

Mobile Switching Center and Visitor Location Register
The Mobile Switching Center (MSC) performs the communications switching functions of the system and is responsible for call set-up, release, and routing. It also provides functions for service billing and for interfacing other networks.
The Visitor Location Register (VLR) contains dynamic information about users who are attached to the mobile network including the user’s geographical location. The VLR is usually integrated to the MSC.
Through the MSC, the mobile network communicates with other networks such as the Public Switched Telephone Network (PSTN), Integrated Services Digital Network (ISDN), Circuit Switched Public Data Network (CSPDN), and Packet Switched Public Data Network (PSPDN).

Home Location Register
The Home Location Register (HLR) is a network element containing subscription details for each subscriber. An HLR is typically capable of managing information for hundreds of thousands of subscribers. In a GSM network, signaling is based on the Signaling System Number 7 (SS7) protocol.
The use of SS7 is complemented by the use of the Mobile Application Part (MAP) protocol for mobile specific signaling. In particular, MAP is used for the exchange of location and subscriber information between the HLR and other network elements such as the MSC. For each subscriber, the HLR maintains the mapping between the International Mobile Subscriber Identity (IMSI) and the Mobile Station ISDN Number (MSISDN).

an Introduction

Generations of Mobile Communications Networks:

In the 1980s, first generation (1G) mobile systems arrived in Nordic countries. These First generation systems were characterized by analog wireless communications and limited Support for user mobility.
Digital communications technology was introduced with second generation (2G) mobile systems in the 1990s. Second generation systems benefited from the cellular concept in which scarce radio resources are used simultaneously by several mobile users without interference. Early 2004, first third generation (3G) mobile systems have been deployed in several European countries. With 3G systems, various wireless technologies converge with Internet technologies.

Telecommunications Context: Standardization and Regulation:

In the telecommunications environment, Standard Development Organizations (SDOs) provide the necessary framework for the development of standards. In the early days of mobile communications, various regional SDOs developed specifications for network technologies and services independently. In 1998, such an effort was initiated by several SDOs including ARIB (Japan), ETSI (Europe), TTA (Korea), TTC (Japan), and T1 (USA). The initiative was named the Third Generation Partnership Project (3GPP).