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In this tutorial, we have taught you all the basic concepts related to GPRS technology. Hope, now you have basic understanding of GPRS Technology.
You have learnt about GPRS basic overview, its architecture, a short description of GSM protocol stack and available GPRS applications. We also told you how you can charge GPRS services.
A list of all the important GPRS Acronyms has been given for your quick reference. So you can book mark this page for future reference.
What is Next ?
We have now seen that GPRS is a crucial step in the mobile evolution, and it opens endless possibilities for application developers and users. The next step after GPRS can be either EDGE or UMTS (or both).
Enhanced Data rate for GSM Evolution (EDGE) : using a new modulation scheme to provide up to three times higher throughput (for HSCSD and GPRS)
Universal Mobile Telecommunication System (UMTS) : a new wireless technology using new infrastructure deployment.
If you are not aware of GSM technology, then our Simple GSM tutorial will give you a very good start up.
Now, if you need more detail about GPRS technology, then I would recommend you to go through other GSM resources listed in GPRS Useful Resources chapter.
You have learnt about GPRS basic overview, its architecture, a short description of GSM protocol stack and available GPRS applications. We also told you how you can charge GPRS services.
A list of all the important GPRS Acronyms has been given for your quick reference. So you can book mark this page for future reference.
What is Next ?
We have now seen that GPRS is a crucial step in the mobile evolution, and it opens endless possibilities for application developers and users. The next step after GPRS can be either EDGE or UMTS (or both).
Enhanced Data rate for GSM Evolution (EDGE) : using a new modulation scheme to provide up to three times higher throughput (for HSCSD and GPRS)
Universal Mobile Telecommunication System (UMTS) : a new wireless technology using new infrastructure deployment.
If you are not aware of GSM technology, then our Simple GSM tutorial will give you a very good start up.
Now, if you need more detail about GPRS technology, then I would recommend you to go through other GSM resources listed in GPRS Useful Resources chapter.
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GPRS has almost become a default or a mandatory feature of the latest GSM phones. In case you have plans to buy a GPRS enabled mobile phone, then; GSM mobile phone should be opted than going for CDMA technology.
GSMArena.com is a website that has become a one-stop shop for all the latest GSM Mobile Phones. The page below displays a list of latest GSM mobile phones subscribers is a courtesy of GSM Arena. As a staunch follower of this site, I suggest you to go through all the reviews posted on the site, and pick the best suitable mobile phone.
At present, numerous noted mobile device manufacturers provide state–of-the-art mobile handsets:
GSMArena.com is a website that has become a one-stop shop for all the latest GSM Mobile Phones. The page below displays a list of latest GSM mobile phones subscribers is a courtesy of GSM Arena. As a staunch follower of this site, I suggest you to go through all the reviews posted on the site, and pick the best suitable mobile phone.
At present, numerous noted mobile device manufacturers provide state–of-the-art mobile handsets:
| Alcatel | Amoi |
| Apple | Asus |
| Benefon | BenQ |
| BenQ-Siemens | Bird |
| BlackBerry | Bosch |
| Chea | Ericsson |
| Eten | Fujitsu Siemens |
| Gigabyte | Haier |
| HP | HTC |
| i-mate | Innostream |
| Kyocera | LG |
| Maxon | Mitac |
| Mitsubishi | Motorola |
| NEC | Neonode |
| Nokia | O2 |
| Palm | Panasonic |
| Pantech | Philips |
| Qtek | Sagem |
| Samsung | Sendo |
| Sewon | Sharp |
| Siemens | Sony |
| Sony Ericsson | Tel.Me. |
| Telit | Thuraya |
| Toshiba | Vertu |
| VK Mobile | WND |
| XCute |
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As packet data is introduced into mobile systems, the question of how to bill for the services arises. Always online and paying by the minute does not sound all that appealing. Here, we describe the possibilities but it totally depends on different service providers, how they want to charge their customers.
The SGSN and GGSN register all possible aspects of a GPRS user's behavior and generate billing information accordingly. This information is gathered in so-called Charging Data Records (CDR) and is delivered to a billing gateway.
The GPRS service charging can be based on the following parameters:
The SGSN and GGSN register all possible aspects of a GPRS user's behavior and generate billing information accordingly. This information is gathered in so-called Charging Data Records (CDR) and is delivered to a billing gateway.
The GPRS service charging can be based on the following parameters:
- Volume - The amount of bytes transferred, i.e., downloaded and uploaded.
- Duration - The duration of a PDP context session.
- Time - Date, time of day, and day of the week (enabling lower tariffs at offpeak hours).
- Final destination - A subscriber could be charged for access to the specific network, such as through a proxy server.
- Location - The current location of the subscriber.
- Quality of Service - Pay more for higher network priority.
- SMS - The SGSN will produce specific CDRs for SMS.
- Served IMSI/subscriber - Different subscriber classes (different tariffs for frequent users, businesses, or private users).
- Reverse charging - The receiving subscriber is not charged for the received data; instead, the sending party is charged.
- Free of charge - Specified data to be free of charge.
- Flat rate - A fixed monthly fee.
- Bearer service - Charging based on different bearer services (for an operator who has several networks, such as GSM900 and GSM1800, and who wants to promote usage of one of the networks). Or, perhaps the bearer service would be good for areas where it would be cheaper for the operator to offer services from a wireless LAN rather than from the GSM network.
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This chapter gives a brief description of the basic processes used in GPRS networks:
- Attach process - Process by which the MS attaches (i.e., connects) to the SGSN in a GPRS network.
- Authentication process - Process by which the SGSN authenticates the mobile subscriber.
- PDP activation process - Process by which a user session is established between the MS and the destination network.
- Detach process - Process by which the MS detaches (i.e., disconnects) from the SGSN in the GPRS network.
- Network-initiated PDP request for static IP address - Process by which a call from the packet data network reaches the MS using a static IP address.
- Network-initiated PDP request for dynamic IP address - Process by which a call from the packet data network reaches the MS using a dynamic IP address.
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The GPRS access modes specify whether or not the GGSN requests user authentication at the access point to a Public Data Network (PDN). The available options are:
In transparent access mode, the MS is given an address belonging to the operator or any other addressing space of domain. The address is given either at subscription as a static address or at PDP context activation, as a dynamic address. The dynamic address is allocated from a Dynamic Host Configuration Protocol (DHCP) server in the GPRS network. Any user authentication is done within the GPRS network. No RADIUS authentication is performed; only IMSI-based authentication (from the subscriber identity module in the handset) is done.
- Transparent - No security authorization/authentication is requested by the GGSN.
- Non-transparent - In this case, GGSN acts as a proxy for authenticating.
Transpatent Mode
Transparent access pertains to a GPRS PLMN that is not involved in subscriber access authorization and authentication. Access to PDN-related security procedures are transparent to GSNs.In transparent access mode, the MS is given an address belonging to the operator or any other addressing space of domain. The address is given either at subscription as a static address or at PDP context activation, as a dynamic address. The dynamic address is allocated from a Dynamic Host Configuration Protocol (DHCP) server in the GPRS network. Any user authentication is done within the GPRS network. No RADIUS authentication is performed; only IMSI-based authentication (from the subscriber identity module in the handset) is done.
Non Transpatent Mode
Non-transparent access to an intranet/ISP means that the PLMN plays a role in the intranet/ISP authentication of the MS. Non-transparent access uses the Password Authentication Protocol (PAP) or Challenge Handshake Authentication Protocol (CHAP) message issued by the mobile terminal and piggybacked in the GTP PDP context activation message. This message is used to build a RADIUS request toward the RADIUS server associated with the access point name (APN).GPRS Access Point Name
- The GPRS standards define a network identity called an Access Point Name (APN). An APN identifies a PDN that is accessible from a GGSN node in a GPRS network. In GPRS, only the APN is used to select the target network. To configure an APN, the operator configures three elements on the GSN node:
- Access point - Defines an APN and its associated access characteristics, including security (RADIUS), dynamic address allocation (DHCP), and DNS services.
- Access point list - Defines a logical interface that is associated with the virtual template.
- Access group - Defines whether access is permitted between the PDN and the MS
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Data routing or routing of data packets to and fro from a mobile user, is one of the pivot requisites in the GPRS network. The requirement can be divided into two areas:
- Data packet routing
- Mobility management.
Data Packet Routing
The important roles of GGSN involve synergy with the external data network. The GGSN updates the location directory using routing information supplied by the SGSNs about the location of an MS. It routes the external data network protocol packet encapsulated over the GPRS backbone to the SGSN currently serving the MS. It also decapsulates and forwards external data network packets to the appropriate data network and collects charging data that is forwarded to a charging gateway (CG).
There are three important routing schemes:
- Mobile-originated message - This path begins at the GPRS mobile device and ends at the host.
- Network-initiated message when the MS is in its home network - This path begins at the host and ends at the GPRS mobile device.
- Network-initiated message when the MS roams to another GPRS network -This path begins at the host of visited network and ends at the GPRS mobile device.
The GPRS network encapsulates all data network protocols into its own encapsulation protocol called the GPRS tunnelling protocol (GTP). The GTP ensures security in the backbone network and simplifies the routing mechanism and the delivery of data over the GPRS network.
Mobility Management
The operation of the GPRS is partly independent of the GSM network. However, some procedures share the network elements with current GSM functions to increase efficiency and to make optimum use of free GSM resources (such as unallocated time slots).
An MS can be in any of the following three states in the GPRS system. The three-state model is unique to packet radio. GSM uses a two-state model either idle or active.
Active State
Data is transmitted between an MS and the GPRS network only when the MS is in the active state. In the active state, the SGSN knows the cell location of the MS.
Packet transmission to an active MS is initiated by packet paging to notify the MS of an incoming data packet. The data transmission proceeds immediately after packet paging through the channel indicated by the paging message. The purpose of the paging message is to simplify the process of receiving packets. The MS listens to only the paging messages instead of to all the data packets in the downlink channels. This reduces battery usage significantly.
When an MS has a packet to transmit, it must access the uplink channel (i.e., the channel to the packet data network where services reside). The uplink channel is shared by a number of MSs, and its use is allocated by a BSS. The MS requests use of the channel in a random access message. The BSS allocates an unused channel to the MS and sends an access grant message in reply to the random access message.
Standby State
In the standby state, only the routing area of the MS is known. (The routing area can consist of one or more cells within a GSM location area).
When the SGSN sends a packet to an MS that is in the standby state, the MS must be paged. Because the SGSN knows the routing area of the MS, a packet paging message is sent to the routing area. On receiving the packet paging message, the MS relays its cell location to the SGSN to establish the active state.
Idle State
In the idle state, the MS does not have a logical GPRS context activated or any Packet-Switched Public Data Network (PSPDN) addresses allocated. In this state, the MS can receive only those multicast messages that can be received by any GPRS MS. Because the GPRS network infrastructure does not know the location of the MS, it is not possible to send messages to the MS from external data networks.
Routing Updates
When an MS that is in an active or a standby state moves from one routing area to another within the service area of one SGSN, it must perform a routing update. The routing area information in the SGSN is updated, and the success of the procedure is indicated in the response message.
A cell-based routing update procedure is invoked when an active MS enters a new cell. The MS sends a short message containing the identity of the MS and its new location through GPRS channels to its current SGSN. This procedure is used only when the MS is in the active state.
The inter-SGSN routing update is the most complicated routing update. The MS changes from one SGSN area to another, and it must establish a new connection to a new SGSN. This means creating a new logical link context between the MS and the new SGSN and informing the GGSN about the new location of the MS.
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PDP stands for Packet Data Protocol. The PDP addresses are network layer addresses (Open Standards Interconnect [OSI] model Layer 3). GPRS systems support both X.25 and IP network layer protocols. Therefore, PDP addresses can be X.25, IP, or both.
Each PDP address is anchored at a Gateway GPRS Support Node (GGSN), as shown in figure below. All packet data traffic sent from the public packet data network for the PDP address goes through the gateway (GGSN).
The public packet data network is only concerned that the address belongs to a specific GGSN. The GGSN hides the mobility of the station from the rest of the packet data network and from computers connected to the public packet data network.
Statically assigned PDP addresses are usually anchored at a GGSN in the subscriber's home network. Conversely, dynamically assigned PDP addresses can be anchored either in the subscriber's home network or the network that the user is visiting.
When a MS is already attached to a SGSN and it is about to transfer data, it must activate a PDP address. Activating a PDP address establishes an association between the current SGSN of mobile device and the GGSN that anchors the PDP address.
The record kept by the SGSN and the GGSN regarding this association is called the PDP context.
It is important to understand the difference between a MS attaching to a SGSN and a MS activating a PDP address. A single MS attaches to only one SGSN, however, it may have multiple PDP addresses that are all active at the same time.
Each of the addresses may be anchored to a different GGSN. If packets arrive from the public packet data network at a GGSN for a specific PDP address and the GGSN does not have an active PDP context corresponding to that address, it may simply discard the packets. Conversely, the GGSN may attempt to activate a PDP context with a MS if the address is statically assigned to a particular mobile device.
Each PDP address is anchored at a Gateway GPRS Support Node (GGSN), as shown in figure below. All packet data traffic sent from the public packet data network for the PDP address goes through the gateway (GGSN).
 |
Statically assigned PDP addresses are usually anchored at a GGSN in the subscriber's home network. Conversely, dynamically assigned PDP addresses can be anchored either in the subscriber's home network or the network that the user is visiting.
When a MS is already attached to a SGSN and it is about to transfer data, it must activate a PDP address. Activating a PDP address establishes an association between the current SGSN of mobile device and the GGSN that anchors the PDP address.
The record kept by the SGSN and the GGSN regarding this association is called the PDP context.
It is important to understand the difference between a MS attaching to a SGSN and a MS activating a PDP address. A single MS attaches to only one SGSN, however, it may have multiple PDP addresses that are all active at the same time.
Each of the addresses may be anchored to a different GGSN. If packets arrive from the public packet data network at a GGSN for a specific PDP address and the GGSN does not have an active PDP context corresponding to that address, it may simply discard the packets. Conversely, the GGSN may attempt to activate a PDP context with a MS if the address is statically assigned to a particular mobile device.
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Mobile Station Classes talk about the globally-known equipment handset which is also known as Mobile Station (MS) and its three different classes. This equipment, more popular as handset, is used to make phone calls and access data services. The MS comprises of Terminal Equipment (TE) and Mobile Terminal (MT).
TE is the equipment that accommodates the applications and the user interaction, while the MT is the part that connects to the network.
In the following example, Palm Pilot is TE and Mobile phone is MT.
In order to take advantage of the new GPRS services, we need new GPRS enabled handsets. There are three different classes of GPRS terminal equipments:
Class A
Class A terminals can manage both packet data and voice simultaneously. Which means, one needs two transceivers, as the handset has to send or receive data and voice at the same time.This is the main reason why class A terminals are high-priced to manufacture than class B and C terminals.
Class B
Class B terminals do not play the same role like Class A. These terminals can manage either packet data or voice at a time. One can use a single transceiver for both, resulting in the low cost of terminals.
For example, If a user is using the GPRS session (like WAP browsing, file transfer, etc.) then this session is halted if he or she receives a call. This terminal does not allow both the sessions active in one go. This backlog needs rectification thereby giving the user a facility of both receiving a call and maintaining the data session.
Class C
Class C terminals can manage either only packet data or only voice. Examples of class C terminals are GPRS PCM/CIA cards, embedded modules in vending machines, and so on.
Due to the high cost of class A handsets, most handset manufacturers have announced that their first handsets will be class B. Currently, work is going on in 3GPP to standardize a lightweight class A in order to make handsets with simultaneous voice and data available at a reasonable cost.
TE is the equipment that accommodates the applications and the user interaction, while the MT is the part that connects to the network.
In the following example, Palm Pilot is TE and Mobile phone is MT.
In order to take advantage of the new GPRS services, we need new GPRS enabled handsets. There are three different classes of GPRS terminal equipments:
Class A
Class A terminals can manage both packet data and voice simultaneously. Which means, one needs two transceivers, as the handset has to send or receive data and voice at the same time.This is the main reason why class A terminals are high-priced to manufacture than class B and C terminals.
Class B
Class B terminals do not play the same role like Class A. These terminals can manage either packet data or voice at a time. One can use a single transceiver for both, resulting in the low cost of terminals.
For example, If a user is using the GPRS session (like WAP browsing, file transfer, etc.) then this session is halted if he or she receives a call. This terminal does not allow both the sessions active in one go. This backlog needs rectification thereby giving the user a facility of both receiving a call and maintaining the data session.
Class C
Class C terminals can manage either only packet data or only voice. Examples of class C terminals are GPRS PCM/CIA cards, embedded modules in vending machines, and so on.
Due to the high cost of class A handsets, most handset manufacturers have announced that their first handsets will be class B. Currently, work is going on in 3GPP to standardize a lightweight class A in order to make handsets with simultaneous voice and data available at a reasonable cost.
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Quality of Service (QoS) requirements of conventional mobile packet data applications are in assorted forms. The QoS is a vital feature of GPRS services as there are different QoS support requirements for assorted GPRS applications like realtime multimedia, web browsing, and e-mail transfer.
GPRS allows defining QoS profiles using the following parameters :Service Precedence
This includes all delays within the GPRS network, e.g., the delay for request and assignment of radio resources and the transit delay in the GPRS backbone network. Transfer delays outside the GPRS network, e.g., in external transit networks, are not taken into account.
Using these QoS classes, QoS profiles can be negotiated between the mobile user and the network for each session, depending on the QoS demand and the available resources.
The billing of the service is then based on the transmitted data volume, the type of service, and the chosen QoS profile.
GPRS allows defining QoS profiles using the following parameters :Service Precedence
- Reliability
- Delay and
- Throughput
Service Precedence
The preference given to a service when compared to another service is known as Service Precedence.This level of priority is classified into three levels called:- high
- normal
- low
Reliability
This parameter signifies the transmission characteristics required by an application.The reliability classes are defined which guarantee certain maximum values for the probability of loss, duplication, mis-sequencing, and corruption of packets.Delay
The delay is defined as the end-to-end transfer time between two communicating mobile stations or between a mobile station and the GI interface to an external packet data network.This includes all delays within the GPRS network, e.g., the delay for request and assignment of radio resources and the transit delay in the GPRS backbone network. Transfer delays outside the GPRS network, e.g., in external transit networks, are not taken into account.
Throughput
The throughput specifies the maximum/peak bit rate and the mean bit rate.Using these QoS classes, QoS profiles can be negotiated between the mobile user and the network for each session, depending on the QoS demand and the available resources.
The billing of the service is then based on the transmitted data volume, the type of service, and the chosen QoS profile.
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The flow of GPRS protocol stack and end-to-end message from MS to the GGSN is displayed in the below diagram. GTP is the protocol used between the SGSN and GGSN using the Gn interface.
This is a Layer 3 tunneling protocol.
The process that takes place in the application looks like a normal IP sub-network for the users both inside and outside the network. The vital thing that needs attention is, the application communicates via standard IP, that is carried through the GPRS network and out through the gateway GPRS. The packets that are mobile between the GGSN and the SGSN use the GPRS tunneling protocol, this way the IP addresses located on the external side of the GPRS network do not have deal with the internal backbone. UDP and IP are run by GTP.
SubNetwork
Dependent Convergence Protocol (SNDCP) and Logical Link Control (LLC) combination used in between the SGSN and the MS. The SNDCP flattens data to reduce the load on the radio channel. A safe logical link by encrypting packets is provided by LLC and the same LLC link is used as long as a mobile is under a single SGSN.
In case, the mobile moves to a new routing area that lies under a different SGSN; then, the old LLC link is removed and a new link is established with the new Serving GSN X.25. Services are provided by running X.25 on top of TCP/IP in the internal backbo
This is a Layer 3 tunneling protocol.
The process that takes place in the application looks like a normal IP sub-network for the users both inside and outside the network. The vital thing that needs attention is, the application communicates via standard IP, that is carried through the GPRS network and out through the gateway GPRS. The packets that are mobile between the GGSN and the SGSN use the GPRS tunneling protocol, this way the IP addresses located on the external side of the GPRS network do not have deal with the internal backbone. UDP and IP are run by GTP.
SubNetwork
Dependent Convergence Protocol (SNDCP) and Logical Link Control (LLC) combination used in between the SGSN and the MS. The SNDCP flattens data to reduce the load on the radio channel. A safe logical link by encrypting packets is provided by LLC and the same LLC link is used as long as a mobile is under a single SGSN.
In case, the mobile moves to a new routing area that lies under a different SGSN; then, the old LLC link is removed and a new link is established with the new Serving GSN X.25. Services are provided by running X.25 on top of TCP/IP in the internal backbo
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GPRS architecture works on the same procedure like GSM network, but, has additional entities that allow packet data transmission. This data network overlaps a second-generation GSM network providing packet data transport at the rates from 9.6 to 171 kbps. Along with the packet data transport the GSM network accommodates multiple users to share the same air interface resources concurrently.
Following is the GPRS Architecture diagram:
GPRS attempts to reuse the existing GSM network elements as much as possible, but to effectively build a packet-based mobile cellular network, some new network elements, interfaces, and protocols for handling packet traffic are required.
Therefore, GPRS requires modifications to numerous GSM network elements as summarized below:
BTS
A software upgrade is required in the existing Base Transceiver Station(BTS).
BSC
The Base Station Controller (BSC) requires a software upgrade and the installation of new hardware called the packet control unit (PCU). The PCU directs the data traffic to the GPRS network and can be a separate hardware element associated with the BSC.
GPRS Support Nodes (GSNs)
The deployment of GPRS requires the installation of new core network elements called the serving GPRS support node (SGSN) and gateway GPRS support node (GGSN).
Databases (HLR, VLR, etc.)
All the databases involved in the network will require software upgrades to handle the new call models and functions introduced by GPRS.
GPRS Mobile Stations
New Mobile Stations (MS) are required to use GPRS services because existing GSM phones do not handle the enhanced air interface or packet data. A variety of MS can exist, including a high-speed version of current phones to support high-speed data access, a new PDA device with an embedded GSM phone, and PC cards for laptop computers. These mobile stations are backward compatible for making voice calls using GSM.
GPRS Base Station Subsystem
Each BSC requires the installation of one or more Packet Control Units (PCUs) and a software upgrade. The PCU provides a physical and logical data interface to the Base Station Subsystem (BSS) for packet data traffic. The BTS can also require a software upgrade but typically does not require hardware enhancements.
When either voice or data traffic is originated at the subscriber mobile, it is transported over the air interface to the BTS, and from the BTS to the BSC in the same way as a standard GSM call. However, at the output of the BSC, the traffic is separated; voice is sent to the Mobile Switching Center (MSC) per standard GSM, and data is sent to a new device called the SGSN via the PCU over a Frame Relay interface.
GPRS Support Nodes
Following two new components, called Gateway GPRS Support Nodes (GSNs) and, Serving GPRS Support Node (SGSN) are added:
Gateway GPRS Support Node (GGSN)
The Gateway GPRS Support Node acts as an interface and a router to external networks. It contains routing information for GPRS mobiles, which is used to tunnel packets through the IP based internal backbone to the correct Serving GPRS Support Node. The GGSN also collects charging information connected to the use of the external data networks and can act as a packet filter for incoming traffic.
Serving GPRS Support Node (SGSN)
The Serving GPRS Support Node is responsible for authentication of GPRS mobiles, registration of mobiles in the network, mobility management, and collecting information on charging for the use of the air interface.
Internal Backbone
The internal backbone is an IP based network used to carry packets between different GSNs. Tunnelling is used between SGSNs and GGSNs, so the internal backbone does not need any information about domains outside the GPRS network. Signalling from a GSN to a MSC, HLR or EIR is done using SS7.
Routing Area
GPRS introduces the concept of a Routing Area. This concept is similar to Location Area in GSM, except that it generally contains fewer cells. Because routing areas are smaller than location areas, less radio resources are used While broadcasting a page message.
Following is the GPRS Architecture diagram:
GPRS attempts to reuse the existing GSM network elements as much as possible, but to effectively build a packet-based mobile cellular network, some new network elements, interfaces, and protocols for handling packet traffic are required.
Therefore, GPRS requires modifications to numerous GSM network elements as summarized below:
- GSM Network Element
- Modification or Upgrade Required for GPRS.
- Mobile Station (MS)
BTS
A software upgrade is required in the existing Base Transceiver Station(BTS).
BSC
The Base Station Controller (BSC) requires a software upgrade and the installation of new hardware called the packet control unit (PCU). The PCU directs the data traffic to the GPRS network and can be a separate hardware element associated with the BSC.
GPRS Support Nodes (GSNs)
The deployment of GPRS requires the installation of new core network elements called the serving GPRS support node (SGSN) and gateway GPRS support node (GGSN).
Databases (HLR, VLR, etc.)
All the databases involved in the network will require software upgrades to handle the new call models and functions introduced by GPRS.
GPRS Mobile Stations
New Mobile Stations (MS) are required to use GPRS services because existing GSM phones do not handle the enhanced air interface or packet data. A variety of MS can exist, including a high-speed version of current phones to support high-speed data access, a new PDA device with an embedded GSM phone, and PC cards for laptop computers. These mobile stations are backward compatible for making voice calls using GSM.
GPRS Base Station Subsystem
Each BSC requires the installation of one or more Packet Control Units (PCUs) and a software upgrade. The PCU provides a physical and logical data interface to the Base Station Subsystem (BSS) for packet data traffic. The BTS can also require a software upgrade but typically does not require hardware enhancements.
When either voice or data traffic is originated at the subscriber mobile, it is transported over the air interface to the BTS, and from the BTS to the BSC in the same way as a standard GSM call. However, at the output of the BSC, the traffic is separated; voice is sent to the Mobile Switching Center (MSC) per standard GSM, and data is sent to a new device called the SGSN via the PCU over a Frame Relay interface.
GPRS Support Nodes
Following two new components, called Gateway GPRS Support Nodes (GSNs) and, Serving GPRS Support Node (SGSN) are added:
Gateway GPRS Support Node (GGSN)
The Gateway GPRS Support Node acts as an interface and a router to external networks. It contains routing information for GPRS mobiles, which is used to tunnel packets through the IP based internal backbone to the correct Serving GPRS Support Node. The GGSN also collects charging information connected to the use of the external data networks and can act as a packet filter for incoming traffic.
Serving GPRS Support Node (SGSN)
The Serving GPRS Support Node is responsible for authentication of GPRS mobiles, registration of mobiles in the network, mobility management, and collecting information on charging for the use of the air interface.
Internal Backbone
The internal backbone is an IP based network used to carry packets between different GSNs. Tunnelling is used between SGSNs and GGSNs, so the internal backbone does not need any information about domains outside the GPRS network. Signalling from a GSN to a MSC, HLR or EIR is done using SS7.
Routing Area
GPRS introduces the concept of a Routing Area. This concept is similar to Location Area in GSM, except that it generally contains fewer cells. Because routing areas are smaller than location areas, less radio resources are used While broadcasting a page message.
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GPRS has opened a wide range of unique services to the mobile wireless subscriber. Some of the characteristics that have opened a market full of enhanced value services to the users. Below are some of the characteristics:
- Mobility - The ability to maintain constant voice and data communications while on the move.
- Immediacy - Allows subscribers to obtain connectivity when needed, regardless of location and without a lengthy login session.
- Localization - Allows subscribers to obtain information relevant to their current location.
- Using the above three characteristics varied possible applications are being developed to offer to the mobile subscribers. These applications, in general, can be divided into two high-level categories:
- Corporation
- Consumer
These two levels further include:
- Communications - E-mail, fax, unified messaging and intranet/internet access, etc.
- Value-added services - Information services and games, etc.
- E-commerce - Retail, ticket purchasing, banking and financial trading, etc.
- Location-based applications - Navigation, traffic conditions, airline/rail schedules and location finder, etc.
- Vertical applications - Freight delivery, fleet management and sales-force automation.
- Advertising - Advertising may be location sensitive. For example, a user entering a mall can receive advertisements specific to the stores in that mall.
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General Packet Radio System is also known as GPRS is a third-generation step toward internet access. GPRS is also known as GSM-IP that is a Global-System Mobile Communications Internet Protocol as it keeps the users of this system online, allows to make voice calls, and access internet on-the-go. Even Time-Division Multiple Access (TDMA) users benefit from this system as it provides packet radio access.
GPRS also permits the network operators to execute an Internet Protocol (IP) based core architecture for integrated voice and data applications that will continue to be used and expanded for 3G services.
GPRS supersedes the wired connections, as this system has simplified access to the packet data networks like the internet. The packet radio principle is employed by GPRS to transport user data packets in a structure way between GSM mobile stations and external packet data networks. These packets can be directly routed to the packet switched networks from the GPRS mobile stations.
In the current versions of GPRS, networks based on the Internet Protocol (IP) like the global internet or private/corporate intranets and X.25 networks are supported.
Who owns GPRS ?
The GPRS specifications are written by the European Telecommunications Standard Institute (ETSI), the European counterpart of the American National Standard Institute (ANSI).
Key Features
GPRS benefits the users in many ways, one of which is higher data rates in turn of shorter access times. In the typical GSM mobile, setup alone is a lengthy process and equally, rates for data permission are restrained to 9.6 kbit/s. The session establishment time offered while GPRS is in practice is lower than one second and ISDN-line data rates are up to many 10 kbit/s.
Easy Billing
GPRS packet transmission offers a more user-friendly billing than that offered by circuit switched services. In circuit switched services, billing is based on the duration of the connection. This is unsuitable for applications with bursty traffic. The user must pay for the entire airtime, even for idle periods when no packets are sent (e.g., when the user reads a Web page).
In contrast to this, with packet switched services, billing can be based on the amount of transmitted data. The advantage for the user is that he or she can be "online" over a long period of time but will be billed based on the transmitted data volume.
GPRS also permits the network operators to execute an Internet Protocol (IP) based core architecture for integrated voice and data applications that will continue to be used and expanded for 3G services.
GPRS supersedes the wired connections, as this system has simplified access to the packet data networks like the internet. The packet radio principle is employed by GPRS to transport user data packets in a structure way between GSM mobile stations and external packet data networks. These packets can be directly routed to the packet switched networks from the GPRS mobile stations.
In the current versions of GPRS, networks based on the Internet Protocol (IP) like the global internet or private/corporate intranets and X.25 networks are supported.
Who owns GPRS ?
The GPRS specifications are written by the European Telecommunications Standard Institute (ETSI), the European counterpart of the American National Standard Institute (ANSI).
Key Features
Following three key features describe wireless packet data:
- The always online feature - Removes the dial-up process, making applications only one click away.
- An upgrade to existing systems - Operators do not have to replace their equipment; rather, GPRS is added on top of the existing infrastructure.
- An integral part of future 3G systems - GPRS is the packet data core network for 3G systems EDGE and WCDMA.
Goals of GPRS
GPRS is the first step toward an end-to-end wireless infrastructure and has the following goals:
- Open architecture
- Consistent IP services
- Same infrastructure for different air interfaces
- Integrated telephony and Internet infrastructure
- Leverage industry investment in IP
- Service innovation independent of infrastructure
Higher Data Rate
GPRS benefits the users in many ways, one of which is higher data rates in turn of shorter access times. In the typical GSM mobile, setup alone is a lengthy process and equally, rates for data permission are restrained to 9.6 kbit/s. The session establishment time offered while GPRS is in practice is lower than one second and ISDN-line data rates are up to many 10 kbit/s.
Easy Billing
GPRS packet transmission offers a more user-friendly billing than that offered by circuit switched services. In circuit switched services, billing is based on the duration of the connection. This is unsuitable for applications with bursty traffic. The user must pay for the entire airtime, even for idle periods when no packets are sent (e.g., when the user reads a Web page).
In contrast to this, with packet switched services, billing can be based on the amount of transmitted data. The advantage for the user is that he or she can be "online" over a long period of time but will be billed based on the transmitted data volume.
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The following is a compiled list of mobile terms and acronyms taken from a GSM Association supported publication.
1G
The first generation of analogue mobile phone technologies including AMPS, TACS and NMT
2G
The second generation of digital mobile phone technologies including GSM, CDMA IS-95 and D-AMPS IS-136
2.5G
The enhancement of GSM which includes technologies such as GPRS
3G
The third generation of mobile phone technologies covered by the ITU IMT-2000 family
3GPP
The 3rd Generation Partnership Project, a grouping of international standards bodies, operators and vendors with the responsibility of standardising the WCDMA based members of the IMT-2000 family
3GPP2
The counterpart of 3GPP with responsibility for standardising the CDMA2000-based members of the IMT-2000 family. 3GPP2 is spearheaded by ANSI
8PSK
Octantal Phase Shift Keying
A5/1/2/3/8X
Encryption algorithms for GSM networks
AAL
ATM Adaptation Layer
ABR
Available Bit Rate
A-bis
Interface between the BSC and BTS in a GSM network
AB
Access Burst; used for random access and characterised by a longer guard period to allow for burst transmission from a MS that does not know the correct timing advance when first contacting a network
ACTE
Approvals Committee for Terminal Equipment
ACTS
Advanced Communications Technologies and Services, an European technology initiative
ACU
Antenna Combining Unit
ADPCM
Adaptive Differential Pulse Code Modulation; a form of voice compression that typically uses 32kbit/s
AFC
Automatic Frequency Control
AGCH
Access Grant Channel; downlink only, BTS allocates a TCH or SDCCH to the MS, allowing it access to the network
Air interface
In a mobile phone network, the radio transmission path between the base station and the mobile terminal
A-interface
Interface between the MSC and BSS in a GSM network
AM
Amplitude Modulation
AMPS
Advanced Mobile Phone System, the analogue mobile phone technology used in North and South America and in around 35 other countries. Operates in the 800MHz band using FDMA technology
AMR
Adaptive Multi-Rate codec. Developed in 1999 for use in GSM networks, the AMR has been adopted by 3GPP for 3G
Analogue
The representation of information by a continuously variable physical quantity such as voltage
ANSI
American National Standards Institute. An non-profit making US organisation, which does not carry out standardisation work but reviews the work of standards bodies and assigns them category codes and numbers
ANSI-136
See D-AMPS
API
Application Program Interface
AoC
Advice of Charge
ARIB
Association of Radio Industries and Businesses. An organisation established by Japan's Ministry of Posts and Communications to act as the standardisation authority for radio communication and broadcasting
ARPU
Average Revenue Per User
ASCII
American Standard Code for Information Interchange
ASIC
Application Specific Integrated Circuit
ASP
Application Service Provider
Asymmetric Transmission
Data transmissions where the traffic from the network to the subscriber is at a higher rate than the traffic from the subscriber to the network
A-TDMA
Advanced Time Division Multiple Access
ATM
Asynchronous Transfer Mode; a multiplexed information transfer and switching method in which the data is organised into fixed length 53-octet cells and transmitted according to each application.s instantaneous need
AUC
Authentication Centre; the element within a GSM network which generates the parameters for subscriber authentication
Bandwidth
A term meaning both the width of a transmission channel in terms of Hertz and the maximum transmission speed in bits per second that it will support
BCH
Broadcast Channels; carry only downlink information and are mainly responsible for synchronisation and frequency correction (BCCH, FCCH and SCH)
BCCH
Broadcast Control Channel; the logical channel used in cellular networks to broadcast signalling and control information to all mobile phones within the network
B-CDMA
Broadband Code Division Multiple Access
B-ISDN
Broadband ISDN
BER
Bit Error Rate; the percentage of received bits in error compared to the total number of bits received
BERT
Bit Error Rate Test
Bit
A bit is the smallest unit of information technology. As bits are made up using the binary number system, all multiples of bits must be powers of two, i.e., a kilobit is actually 1024 bits and a megabit 1048576 bits. Transmission speeds are given in bits per second (bit/s)
Bluetooth
A low power, short range wireless technology designed to provide a replacement for the serial cable. Operating in the 2.4GHz ISM band, Bluetooth can connect a wide range of personal, professional and domestic devices such as laptop computers and mobile phones together wirelessly
BHCA
Busy Hour Call Attempts; the number of call attempts made during a network's busiest hour of the day
BSC
Base Station Controller; the network entity controlling a number of Base Transceiver Stations
BSS
Base Station System/Subsystem
BTS
Base Transceiver Station; the network entity, which communicates with the mobile station
CAI
Common Air Interface; a standard developed for the UK's public CT2 networks which enabled the same handset to be used on different networks
CAMEL
Customised Application for Mobile network Enhanced Logic; an IN feature in GSM networks that enables users to carry personal services with them when roaming into other networks that support CAMEL
CSE
CAMEL Service Environment
Capacity
A measure of a cellular network's ability to support simultaneous calls
CB
Cell Broadcast
CC
Call Control; manages call connections
CCB
Customer Care and Billing
CCCH
Common Control Channels; a group of uplink and downlink channels between the MS and the BTS (see PCH, AGCH and RACH)
CCS7
Common Channel Signalling No. 7
CDMA
Code Division Multiple Access; also known as spread spectrum, CDMA cellular systems utilise a single frequency band for all traffic, differentiating the individual transmissions by assigning them unique codes before transmission. There are a number of variants of CDMA (see W-CDMA, B-CDMA, TD-SCDMA et al)
CDMAone
The first commercial CDMA cellular system; deployed in North America and Korea; also known as IS-95
CDMA2000
A member of the IMT-2000 3G family; backwardly compatible with cdmaOne
CDMA 1X
The first generation of cdma2000; the standardisation process indicated that there would be CDMA 2X and CDMA 3X but this no longer appears likely
CDMA 1X EV-DO
A variant of CDMA 1X which delivers data only
CDPD
Cellular Digital Packet Data; a packet switched data service largely deployed in the USA. The service uses idle analogue channels to carry the packetised information
CDPSK
Coherent Differential Phase Shift Keying
CDR
Call Detail Records; the record made within the cellular network of all details of both incoming and outgoing calls made by subscribers, The CDR is passed to the billing system for action
Cell
The area covered by a cellular base station. A cell site may sectorise its antennas to service several cells from one locationCell site
The facility housing the transmitters/receivers, the antennas and associated equipment
Cell splitting
The process of converting a single cell to multiple cells by sectorising the antennas in the cell site or constructing additional cells within a cell site
CELP
Code Excited Linear Prediction; an analogue to digital voice coding scheme, there are a number of variants used in cellular systems
CEPT
Conference of European Posts and Telecommunications. A organisation of national posts, telegraphs and telephone administrations. Until 1988, when this work was taken over by ETSI, the main European body for telecommunications standardisation. CEPT established the original GSM standardisation group
CF
Call Forwarding
CI
Carrier to Interference ratio
CIBER
Cellular Intercarrier Billing Exchange Roamer Record
CID
Caller Identification
Circuit switching
A method used in telecommunications where a temporary dedicated circuit of constant bandwidth is established between two distant endpoints in a network. Mainly used for voice traffic; the opposite of packet switching
CLID
Calling Line Identification
CLIP
Calling Line Identification Presentation
CLIR
Calling Line Identification Restriction
CM
Connection Management; is used to set up, maintain and take down call connections
CMOS
Complementary Metal Oxide Substrate
Codec
A word formed by combining coder and decoder, the codec is a device, which encodes and decodes signals. The voice codec in a cellular network converts voice signals into and back from bit strings. In GSM networks, in addition to the standard voice codec, it is possible to implement Half Rate (HR) codecs and Enhanced Full Rate (EFR) codecs
Control signal
A signal sent to a cellular phone from a base station or vice versa which carries information essential to the call but not including the audio portion of a conversation
CPE
Customer Premises Equipment; all the equipment on the end user.s side of the network interface
CPU
Central Processing Unit
CRC
Cyclic Redundancy Check
CRM
Customer Relationship Management
CSS
Customer Support System
CT
Cordless Telephony
CT0
Zero generation cordless telephony; the earliest domestic cordless phones which used analogue technology and which had severe limitations in terms of range and security
CT1
First generation cordless telephony; Improved analogue phones with greater range and security; a number of European nations produced CT1 standards
CT2
Second generation cordless telephony; Using digital technology CT2 phones offered greater range, improved security and a wide range of new functionalities. Used in both domestic and cordless PABX deployments, CT2 was standardised as an interim ETS but was overwhelmed by DECT
CT2-CAI
Second generation cordless telephony-common air interface
CTA
Cordless Terminal Adaptor; a DECT term
CTM
Cordless Terminal Mobility
CTR
Common Technical Regulation; part of the ETSI standardisation process
CUG
Closed User Group
D/A
Digital to Analogue conversion
DAC
Digital to Analogue Converter
DAMA
Demand Assigned Multiple Access
D-AMPS
Digital AMPS, a US wireless standard also known as IS-136
DAN
DECT Access Node
DCA
Dynamic Channel Assignment
DCCH
Dedicated Control Channels; responsible for roaming, handovers, encryption, etc., (See SDCCH, SACCH and FACCH)
DCE
Data Communications Equipment
DCH
Data Clearing House
DCPSK
Differentially Coherent Phase Shift Keying
DCS1800
Digital Cellular System at 1800MHz, now known as GSM1800
DECT
Digitally Enhanced Cordless Telecommunications system, a second generation digital cordless technology standardised by ETSI
DEPSK
Differential Encoded Phase Shift Keying
DES
Digital Encryption Standard
DFSK
Double Frequency Shift Keying
Digital
a method of representing information as numbers with discrete values; usually expressed as a sequence of bits
DPCM
Differential Pulse Code Modulation
DPSK
Digital Phase Shift Keying
DQPSK
Digital Quadrature Phase Shift Keying
DS-CDMA
Direct Sequence CDMA
DSP
Digital Signal Processing
DSRR
Digital Short Range Radio; a UK standard for a low power, short range radio system designed for small voice and data networks
DTE
Data Terminal Equipment
DTMF
Dual Tone MultiFrequency; better know as Touch Tone. The tones generated by touching the keys on the phone are used for a variety of purposes including voice mail systems and voice messaging
DTX
Discontinuous Transmission
Dual Band
The capability of GSM infrastructure elements and handsets to work across both the 900MHz and 1800MHz bands. The capability to seamlessly handover between the two bands offers operators major capacity gains
DB
Dummy Burst; transmitted as a filler in unused timeslots of the carrier
Duplex
The wireless technique where one frequency band is used for traffic from the network to the subscriber (the downlink) and another, widely separated, band is used for traffic from the subscriber to the network (the uplink)
EDGE
Enhanced Data rates for GSM Evolution; effectively, the final stage in the evolution of the GSM standard, EDGE uses a new modulation schema to enable theoretical data speeds of up to 384kbit/s within the existing GSM spectrum. An alternative upgrade path towards 3G services for operators, such as those in the USA, without access to new spectrum. Also known as Enhanced GPRS (E-GPRS)
EEPROM
Electrically Erasable Programmable Read Only Memory
EFR
Enhanced Full Rate; an alternative voice codec that provides improved voice quality in a GSM network (see codec)
EFT
Electronic Funds Transfer
EGSM
Extended (frequency range) GSM
EIR
Equipment Identity Register; a database that contains a list of all valid mobile stations within a network based on their IMEI
EIRP
Effective Isotropic Radiated Power
EPOC
The mobile phone operating system developed by Symbian. Derived from epoch-the beginning of an era-EPOC is a 32-bit operating environment, which comprises a suite of applications, customisable user interfaces, connectivity options and a range of development tools.
EPROM
Erasable Programmable Read Only Memory
Erlang
A dimensionless unit of average traffic density in a telecommunications network
ERMES
Enhanced Radio Messaging System; a paging technology developed by ETSI which was intended to allow users to roam throughout Europe. Adopted by a number of European and Middle Eastern countries, ERMES, like paging in general, was overtaken by the ubiquity of GSM
ERO
European Radiocommunications Office
ERP
Effective Radiated Power
ESMR
Enhanced Special Mobile Radio; a US PMR variant (see SMR)
ESN
Electronic Serial Number; a 32-bit number that uniquely identifies a mobile phone
ESPRIT
European Strategic Programme for Research and Development in Information Technology
ETACS
Extended TACS; the extension of TACS by the addition of new frequencies
ETSI
European Telecommunications Standards Institute: The European group responsible for defining telecommunications standards
FACCH
Fast Associated Control Channel; similar to the SDCCH but used in parallel for operation of the TCH. If the data rate of the SACCH is insufficient borrowing mode is used
FB
Frequency Correction Burst; used for frequency synchronisation of the mobile
FCC
Federal Communications Commission; the US regulatory body for telecommunications
FCCH
Frequency Correction Channel; downlink only, correction of MS frequencies, transmission of frequency standard to MS, etc.
FDD
Frequency Division Duplex; a radio technique, which uses paired spectrum; UMTS has an FDD element
FDMA
Frequency Division Multiple Access-a transmission technique where the assigned frequency band for a network is divided into sub-bands, which are allocated to a subscriber for the duration of their calls
FEC
Forward Error Correction
FH
Frequency Hopping
FH-CDMA
Frequency Hopping CDMA
FMC
Fixed Mobile Convergence
FMI
Fixed Mobile Integration
FPLMTS
Future Public Land Mobile Telecommunications System, the original title of the ITU's third generation concept now known as IMT-2000
FRA
Fixed Radio Access; see WLL
FSDPSK
Filtered Symmetric Differential Phase Shift Keying
FSK
Frequency Shift Keying; a method of using frequency modulation to send digital information
FSOQ
Frequency Shift Offset Quadrature Modulation
FSS
Fixed Satellite ServiceGb
The interface between the PCU and the SGSN in a GSM/GPRS network
Gc
The interface between the GGSN and the HLR in a GSM/GPRS network
Gd
The interface between the SGSN and the SMSC in a GSM/GPRS network
Gf
The interface between the SGSN and the EIR in a GSM/GPRS network
Gi
The interface between the GGSN and the Internet in a GPRS network
Gn
The interface between the GGSN and the SGSN in a GPRS network
Gp
The interfaces between the GGSN/SGSN and the Border Gateway in a GPRS network
Gr
The interface between the SGSN and the HLR in a GPRS network
Gs
The interface between the SGSN and the MSC in a GSM/GPRS network
GAIT
GSM/ANSI 136 Interoperability Committee
GAP
Generic Access Profile; a DECT term
Gbit/s
A unit of data transmission rate equal to one billion bits per second
GMSC
Gateway Mobile Services Switching Centre; the gateway between two networks
GCF
Global Certification Forum
Geostationary
Refers to a satellite in equatorial orbit above the earth which appears from the surface to be stationary
GERAN
GSM-EDGE Radio Access Network; the name for the evolution of GSM towards 3G based on EDGE
GGRF
GSM Global Roaming Forum
GGSN
Gateway GPRS Support Node; the gateway between a cellular network and a IP network.
GHz
A unit of frequency equal to one billion Hertz per second
GMPCS
Global Mobile Personal Communications by Satellite
GMSK
Gaussian filtered Minimum Shift Keying; a refinement of FSK which minimises adjacent channel interference
GPRS
General Packet Radio Service; standardised as part of GSM Phase 2+, GPRS represents the first implementation of packet switching within GSM, which is a circuit switched technology. GPRS offers theoretical data speeds of up to 115kbit/s using multislot techniques. GPRS is an essential precursor for 3G as it introduces the packet switched core required for UMTS
GPS
Global Positioning System; a location system based on a constellation of US Department of Defence satellites. Depending on the number of satellites visible to the user can provide accuracies down to tens of metres. Now being incorporated as a key feature in an increasing number of handsets
GRX
GPRS Roaming Exchange
GSM
Global System for Mobile communications, the second generation digital technology originally developed for Europe but which now has in excess of 71 per cent of the world market. Initially developed for operation in the 900MHz band and subsequently modified for the 850, 1800 and 1900MHz bands. GSM originally stood for Group Special Mobile, the CEPT committee, which began the GSM standardisation process
GSM MoU
The GSM Memorandum of Understanding, an agreement signed between all the major European operators to work together to promote GSM. The precursor of the GSM Association
GSM-R
GSM-Railway, A variant of GSM designed to meet the special communications needs of international train operators
Handoff
The transfer of control of a cellular phone call in progress from one cell to another, without any discontinuity
Hands-free
The operation of a cellular phone without using the handset; usually installed in vehicles.
HCS
Hierarchical Cell Structure; the architecture of a multi-layered cellular network where subscribers are handed over from the macro to the micro to the pico layer depending on the current network capacity and the needs of the subscriber
HDLC
High level Data Link Control
HIPERLAN
High Performance Radio Local Access Network; a wireless local area network being standardised by ETSI (Also HIPERLAN2)
HLR
Home Location Register; the database within a GSM network which stores all the subscriber data. An important element in the roaming process
HSCSD
High Speed Circuit Switched Data; a special mode in GSM networks which provides higher data throughput By cocatenating a number of timeslots, each delivering 14.4kbit/s, much higher data speeds can be achieved
HSPSD
High Speed Packet Switched DataIub
The interface between the Node B and the RNC in a UMTS network
Iur
The interface between RNCs in a UMTS network
Iups
The connection between the RNC and the packet switched network in a GSM/GPRS/UMTS network
Iucs
The connection between the RNC and the circuit switched network in a GSM/GPRS/UMTS network
I-ETS
Interim European Telecommunications Standard
I-mode
A service developed by Japanese operator NTT DoCoMo, I-mode delivers a huge range of services to subscribers and has proved enormously popular with some 30 million regular users. The revenue sharing model used for I-mode is being adopted by other operators as the basis for the new services enabled by GPRS and 3G
IMEI
International Mobile Equipment Identity
IMSI
International Mobile Subscriber Identity; an internal subscriber identity used only by the network
IMT-2000
The family of third generation technologies approved by the ITU. There are five members of the family: IMT-DS, a direct sequence WCDMA FDD solution IMT-TC, a WCDMA TDD solution IMT-MC, a multicarrier solution developed from cdma2000 IMT-SC, a single carrier solution developed from IS-136/UWC-136 IMT-FT, a TDMA/TDD solution derived from DECT
IN
Intelligent Network
INAP
Intelligent Network Application Part
Internet
A loose confederation of autonomous databases and networks. Originally developed for academic use the Internet is now a global structure of millions of sites accessible by anyone
Intranet
A private network which utilises the same techniques as the Internet but is accessible only by authorised users
IP
Internet Protocol
IPR
Intellectual Property Rights
IPv6
The next generation of IP addressing designed to replace the current system IPv4 which uses a 32 bit address code which limits the number of possible addresses. IPv6 uses a 128 bit code ensuring that the possible number of IP addresses will be virtually limitless
IrDA
Infra red Data Association
Iridium
A low earth orbit satellite communications system developed initially by Motorola.
IS-54
The first evolution in the USA from analogue to digital technology. Used a hybrid of analogue and digital technology, superseded by IS-136
IS-95
Cellular standard know also as cdmaOne
IS-136
Cellular standard also known as TDMA or D-AMPS
ISDN
Integrated Services Digital Network
ISO
International Standards Organisation
ISP
Internet Service Provider
ITU
International Telecommunications Union
ITU-R
ITU Telecommunications Radio Sector
ITU-T
ITU Telecommunications Standardisation Sector
IWF
Interworking Function
Java
A programming language developed by Sun Microsystems Java is characterised by the fact that programs written in Java do not rely on an operating system
JPEG
Joint Photographic Experts Group
LAN
Local Area Network
LANS
Local Area Network Services
LAP
Link Access Protocol
LEO
Low Earth Orbit; refers to satellites, which orbit the Earth at around 1,000 kilometres
LMSS
Land Mobile Satellite Service
LOS
Line of Sight
MAC
Media Access Control; the lower sublayer of the OSI system
MAN
Metropolitan Area Network
MAP
Mobile Application Part
Mbit/s
Megabit; a unit of data transmission speed equal to one million bits per second
MHz
Megahertz; a unit of frequency equal to one million Hertz
MCPA
Multi Carrier Power Amplifier
MeXe
Mobile Execution Environment; likely to be based on Java, MeXe enables WAP-enabled devices to offer a wider range of features with greater security and flexibility, as well as greater control of telephony features
MFSK
Multiple Frequency Shift Keying
MMI
Man Machine Interface
MMS
Multimedia Messaging Service; an evolution of SMS, MMS goes beyond text messaging offering various kinds of multimedia content including images, audio and video clips
MMSK
Modified Minimum Shift Keying
MNO
Mobile Network Operator
Modulation
The process of imposing an information signal on a carrier. This can be done by changing the amplitude (AM), the frequency (FM) or the phase, or any combination of these
MoU
Memorandum of Understanding - see GSM MoU
MPEG
Motion Picture Experts Group; MPEG4 is a technology for compressing voice and video so that the information can be transmitted over normally difficult links such as mobile radio
MS
Mobile Station
MSC
Mobile Switching Centre; the switching centre of a mobile phone network, the MSC has interfaces to the BSCs, HLR, VLR and other MSCs
MSISDN
Mobile Station International ISDN Number
MSK
Minimum Shift Keying; Another term for FFSK
Multiplexing
A telecommunications technique where several channels can be combined to share the same transmission medium. The most common forms are Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM)
MVPN
Mobile Virtual Private Network
N-AMPS
Narrowband AMPS
NB
Normal Burst; used to carry traffic and control channels except RACH
NET
Norme Europeenne de Telecommunications
NMT
Nordic Mobile Telephone system; an analogue cellular technology deployed in the Nordic countries in the late 1970.s; variations were also deployed in the Benelux countries and in Russia. NMT operated in the 450 and 900MHz bands and was the first technology to offer international roaming, albeit only in the Nordic countries
Node B
The element in a UMTS network which interfaces with the mobile station, analogous to a BTS in a GSM network
OTA
Over the air activation (of services and tariff changes)
O&M
Operations and Maintenance
OMC
Operations and Maintenance Centre
OMC-R
The radio OMC
OMC-S
The switching OMC
OSI
Open Systems Interconnection; a seven layer model for protocols defined by ISO
PACS
Personal Access Communication System; a digital cordless technology developed initially by Bell Labs in the US, PACS was designed to compete with DECT
Packet switching
A communication system wherein the information is transmitted in packets of a set size. These packets have address headers and find their way to their destination by the most efficient route through the network. Compared to circuit switching where a connection is occupied until the traffic exchange is completed, packet switching offers considerable efficiencies as connections can be used by a number of users simultaneously
PAMR
Public Access Mobile Radio; Commercial service using trunking techniques in which multiple groups of users can set up their own closed systems within a shared public network
PAP
Public Access Profile; a DECT term
PCH
Paging Channel; downlink only, the MS is informed of incoming calls by the BTS via the PCH
PCM
Pulse Code Modulation; the standard digital voice format at 64kbit/s
PCMCIA
Personal Computer Memory Card Interface Association the body responsible for defining the standards and formats for memory expansion cards for laptop computers and PDAs. Now extended to cover cards for mobile phones
PCN
Personal Communications Network; a designation initially used in the UK to refer to networks operating in the 1800MHz band (see also DCS1800). No longer in use
PCS 1900
Personal Communications Systems 1900MHz; the terminology used in the US to describe the new digital networks being deployed in the 1900MHz band; rarely used today
PCU
Packet Control Unit; an element in a GPRS/UMTS network
PDA
Personal Digital Assistant
PDC
Personal Digital Communications; a digital cellular technology developed and deployed uniquely in Japan. A TDMA technology, PDC is incompatible with any other digital cellular standard
PEDC
Pan European Digital Communications; A designation occasionally used in the early 1990.s to describe GSM. No longer in use
Penetration
The percentage of the total population which owns a mobile phone
PHS / PHP
Personal HandyPhone System/Phone; a digital cordless technology developed in Japan which achieved great success. Deployed by NTT DoCoMo and other Japanese operators PHS offered two-way communications, data services and Internet access and eventually won some 28 million customers. Now in decline as cellular.s wide area capabilities offer better service
PIN
Personal Identifier Number
PKI
Public Key Infrastructure
PLMN
Public Land Mobile Network; any cellular operator.s network
PMR
Private Mobile Radiocommunications; two-way radio technology widely used for despatch and delivery services, taxi companies and the like. See TETRA
POCSAG
Post Office Code Standardisation Group; a now defunct industry grouping, which standardised pager addressing systems
PoP
Points of Presence; a method of measuring the value of a cellular licence; the approximate number of potential customers within a geographical area
POTS
Plain Old Telephone Service
PROM
Programmable Read Only Memory
PSK
Phase Shift Keying
PSRCP
Public Safety Radio Communications Project; an initiative by the UK Government to standardise all emergency services communications on to a single digital technology (see TETRA)
PSDN
Public Switched Data Network
PSPDN
Public Switched Packet Data Network
PSTN
Public Switched Telephone Network
PSU
Power Supply Unit
PTO
Public Telecommunication Operator
PTT
Posts, Telephone and Telegraph Administration
PTT
Push-to-Talk; a feature of PMR systems
PWT
Personal Wireless Telecommunications; a variant of DECT developed for use in the USA
QAM
Quadrature Amplitude Modulation
QAPSK
Quadrature Amplitude Phase Shift Keying
QCELP
Quadrature Code Excited Linear Prediction
QoS
Quality of Service; a broad term to describe the performance attributes of an end-to-end connection
QPSK
Quadrature Phase Shift Keying
RACE
Research in Advanced Communications in Europe
RACH
Random Access Channel; uplink only, allows the MS to request an SDCCH in response to a page or for a call
RAM
Random Access Memory
RFP
Radio Fixed Part; equivalent to a base station in a DECT system
RCC
Radio Common Carrier
RELP
Regular pulse Excitation Linear Prediction coding
Reuse
The assignment of frequencies or channels to cells so that adjoining cells do not use the same frequencies and cause interference whereas more distant cells can use the same frequencies. Reuse expands the capacity of a cellular network by enabling the use of the same channels throughout the network
RP
Radio Part
RNC
Radio Network Controller; the element which controls the Node Bs within a UMTS network. It is roughly analogous to a BSC in a GSM network
Roaming
A service unique to GSM which enables a subscriber to make and receive calls when outside the service area of his home network, e.g., when travelling abroad
Router
A device which forwards information in a network on a connectionless basis
RRM
Radio Resource Management, part of the UMTS infrastructure
RT
Remote Terminal
SACCH
Slow Associated Control Channel; transmits continuous measurements in parallel with operation of TCH or SDCCH; needed for handover decisions
SAR
Specific Absorption Rate
SB
Synchronisation Burst; used for time synchronisation of the mobile
S-CDMA
Synchronous CDMA (see CDMA)
SCH
Synchronisation Channel; downlink only frame synchronisation and identification of base station
SCP
Switching/Service Control Point
SDCCH
Stand-alone Dedicated Control Channel; communications channel between the MS and the BTS. Used for signalling during call set-up before a TCH is allocated
SDLC
Synchronous Data Link Control
SDMA
Spatial Division Multiple Access
SGSN
Serving GPRS Support Node; the gateway between the RNC and the core network in a GPRS/UMTS network
SIM
Subscriber Identity Module; A smart card containing the telephone number of the subscriber, encoded network identification details, the PIN and other user data such as the phone book. A user.s SIM card can be moved from phone to phone as it contains all the key information required to activate the phone
SoHo
Small Office/Home Office
Streaming
An Internet derived expression for the one-way transmission of video and audio content
STK
SIM ToolKit: specified within the GSM standard, this allows operators to add additional functions to the phone menu in order to provide new services such as mobile banking or email
SMR
Specialised Mobile Radio; the US term for private mobile radio (See PMR)
SMS
Short Message Service; a text message service, which enables users to send short messages (160 characters) to other users. A very popular service, particularly amongst young people, with 400 billion SMS messages sent worldwide in 2002
SMSC
SMS Centre - the network entity, which switches SMS traffic
SMSCB
SMS Cell Broadcast
SMS-MO
SMS Mobile Originated
SMS-MT
SMS Mobile Terminated
SMS-PP
SMS Point to Point
SP
Service Provider
SQAM
Staggered Quadrature Amplitude Modulation
SQPSK
Staggered Quadrature Phase Shift Keying
SS
Supplementary Service Support; handles special services
SS7
Signalling System Number 7 (See CCS7)
SSP
Service Switching Point
STM
Synchronous Transfer Mode
Symbian
A company created by Psion, Nokia, Ericsson and Motorola in 1998 with the aim of developing and standardising an operating system which enable mobile phones from different manufacturers to exchange information
The operating system is known as EPOC. Matsushita has subsequently joined Symbian
TACS
Total Access Communications System (an AMPS variant deployed in a number of countries principally the UK)
TAP
Transferred Account Procedure; the essential charging methodology for international GSM roaming. There have been four TAP standards, TAP1, TAP2, TAP2+ and TAP3. The latter offers variable record length and is sufficiently flexible to support all future requirements arising from the move to 3G
TBR
Technical Basis for Regulation (part of the ETSI standardisation process)
TCH
Traffic Channel
TD-CDMA
Time Division CDMA
TD-SCDMA
Time Division-Synchronous CDMA; a CDMA variant developed by Chinese vendors which is claimed to offer high data rates and greater coverage
TDD
Time Division Duplex; a radio technology for use in unpaired spectrum. WCDMA/UMTS includes a band for TDD mode usage and both PHS and DECT use this technology
TDMA
Time Division Multiple Access; a technique for multiplexing multiple users onto a single channel on a single carrier by splitting the carrier into time slots and allocating these on a as-needed basis
Telematics
A wireless communications system designed for the collection and dissemination of information, particularly refers to vehicle-based electronic systems, vehicle tracking and positioning, on-line vehicle navigation and information systems and emergency assistance
TETRA
Terrestrial Trunked Radio; a European developed digital private mobile radio technology which is now being extensively deployed worldwide
Tetrapol
A competitive digital PMR technology to TETRA developed by French vendors
TFTS
Terrestrial Flight Telephone System
Timeslot
A frame within a TDMA schema; has a time interval of 576 microseconds. Physical content of a timeslot is known as a burst. Five different burst types exist, they are distinguished by different TDMA frame divisions (see NB, FB, SB, AB and DB)
TIPHON
Telecommunications and Internet Protocol Harmonisation over Networks; an ETSI project designed to support the market for voice communications and voice band communications. In particular TIPHON will ensure that users on IP-based networks can communicate with those on circuit switched networks
TMN
Telecommunications Management Network
TMSI
Temporary Mobile Subscriber Identity; covers the IMSI to prevent over-the-air interception and tracing
TRAU
Transcoder Rate Adapter Unit; the transport unit for a 16kbit/s traffic channel on the A-bis interface
Tri-band
Refers to a mobile phone able to operate on the three internationally designated GSM frequencies- 900, 1800 and 1900MHz
TrueSync
A technology which enables the optimal synchronisation of calendars, address books, action lists and memoranda. It enables multi-point, one-step synchronisation of wireless and wireline devices, desktop computers and server-based applications and services
TRX
Transmitter/receiver (transceiver)
User Interface
Um
The air interface between the BTS and the MS in a GSM network
Uu
The air interface between the Node B and the MS in a UMTS network.
UMTS
Universal Mobile Telecommunications System; the European entrant for 3G; now subsumed into the IMT-2000 family as the WCDMA technology.
UPN
Universal Personal Number
UPT
Universal Personal Telecommunications
URL
Uniform Resource Locator; the addressing system of the Internet
USO
Universal Service Obligation
UTRA
Universal Terrestrial Radio Access; the air interface component of WCDMA.
UTRAN
Universal Terrestrial Radio Access Network; the UMTS radio access network comprising the RNC, Node B and the air interface
USIM
Universal Subscriber Identity Module; the 3G equivalent of the GSM SIM
UWB
Ultra Wide Band
VAS
Value Added Services
VBR
Variable Bit Rate
VHE
Virtual Home Environment
VLR
Visitor Location Register
Vocoder
Voice coder
VoIP
Voice over Internet Protocol
VPN
Virtual Private Network
VSAT
Very Small Aperture Terminal
VSELP
Vector Sum Excited Linear Prediction
WAP
Wireless Application Protocol; a de facto standard for enabling mobile phones to access the Internet and advanced services. Users can access websites and pages which have been converted by the use of WML into stripped-down versions of the original more suitable for the limited display capabilities of mobile phones
WARC
World Administration Radio Conference; an ITU conference held at regular intervals to determine the allocation of spectrum for various services
WCDMA
Wideband CDMA; the technology created from a fusion of proposals to act as the European entrant for the ITU IMT-2000 family
WLL
Wireless Local Loop; a technique for providing telephony and low speed data services to fixed customers using wireless. Regarded as having considerably potential for rapidly addressing the telecommunications gap in developing countries. A number of different WLL solutions have been marketed based on cellular and cordless technologies
WLAN
Wireless Local Area Network; a short range radio network normally deployed in traffic hotspots such as airport lounges, hotels and restaurants. WLAN enables suitably equipped users to access the fixed network wirelessly, providing high speed access (up to 11Mbit/s download) to distant servers. The key WLAN technologies are the IEEE802.11 family and ETSI HIPERLAN/2
WML
Wireless Markup Language; a markup language developed specifically for wireless applications. WML is based on XML
WQAM
Weighted Quadrature Amplitude Modulation
WWW
World Wide Web
XML
eXtended Markup Language
The Consumer Mobile Glossary
Advice of charge
A service which provides the user with information on the cost of calls from a mobile phone
Airtime
The amount of time a subscriber spends using his/her mobile phone
Battery status/Battery charge display
An indication of the amount of battery life remaining
Battery
A chargeable device which provides the mobile phone with power. A variety of battery technologies have been used for mobile phones including nickel cadmium (NiCad), nickel metal hydride (NiMH) and lithium ion (Li-ion)
Call barring
A service which enables users to bar certain incoming or outgoing calls on their mobile phones
Call timer
A service which keeps track of the amount of airtime being used by the subscriber on a cumulative basis
Call divert
The capability to divert incoming calls to another phone (fixed or mobile) or to an answering service
Call hold
The ability to put an ongoing call on hold whilst answering or making a second call
Caller ID
Caller Identification; displays the name/number of the person calling a mobile phone. Also known as CLI
CLI
See Caller ID
CLR
Clear; the key on a cellular phone which is pressed to remove information from the display
Data capable
Mobile phones which have the capability to enable transmission of data from a laptop computer or PDA via the phone
Dual band
Mobile phones which support transmission and reception of calls on the 900MHz and 1800MHz bands with seamless handover between the two frequency bands
EFR
Enhanced Full Rate (codec); an improved version of the standard voice codec used in GSM phones; offers improved speech quality without impacting on network capacity
END
The key on a cellular phone which is pressed to terminate a call
Infrared data port
A facility on a mobile phone to allow information to be exchanged with other devices e.g. a PC using infra red technology
Lock
A function on a cellular phone which, when activated, prevents use of the phone until the user enters a security code
No Service
An indication on the display of a cellular phone that indicates that the user is in an area where cellular service is unavailable
One-touch dialling
The ability to dial frequently called numbers using a single key stroke; see Speed Dialling
PCN
Personal Communications Networks; an outdated term for GSM services in the 1800MHz band
PDA
Personal Digital Assistant; a sophisticated handheld device with advanced display facilities and a range of business-oriented software programs
Phone book
A list of personal names and numbers stored in a mobile phone.s internal memory or in the SIM card. These numbers can be called by accessing the appropriate memory and making a single key stroke
PIN
Personal Identity Number; a number, usually four digits, that must be keyed into a mobile phone to make it work. A security measure to prevent unauthorised usage
RCL
The function on a cellular phone which recalls a phone number from memory
Roaming
The ability to make and receive calls on the same mobile phone when travelling outside the area of the home network operator
Smartphone
a combination of mobile phone and personal digital assistant
SND
Send; The key on a cellular phone which initiates a call or answers an incoming call
Speed dialling
See One-touch dialling
Standby time
The length of time a battery can power a mobile phone when it is switched on but not making or receiving calls
Talk-time
The length of time a battery can power a mobile phone when making or receiving calls
Voicemail
A service offered by network operators whereby calls received when the mobile is in use, switched off or out of coverage can be diverted to an answering service which can be personalised by the user
WAP
Wireless Application Protocol; a standard whereby mobile phones can gain access to specially tailored Internet websites
WML
Wireless Markup Language; a specially designed markup language used for tailoring WAP content. WML enables optimum usage of the limited display capabilities of the mobile phone
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