6 Operational Requirements

22.0603GPPGeneral Packet Radio Service (GPRS)Release 17Service descriptionStage 1TS

6.1 GPRS UE Modes of Operation

6.1.1 GPRS UE classes

The purpose of the definition of the GPRS UE Classes is to enable the different needs of the various market segments to be satisfied by a number of UE types with distinct capabilities (e.g., simultaneous use and number of time-slots in GERAN). A means shall be provided to indicate the GERAN multi-slot capability and current configuration to the network when necessary.

Three GPRS UE modes of operation are identified:

NOTE 1: The term simultaneous (attach, traffic, etc.) is the requirement to simultaneously support GPRS services and circuit switched services including SMS.

Class A: The UE is attached to both GPRS and other services. The UE supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation and simultaneous traffic. The mobile user can make and/or receive calls/sessions on the two services simultaneously subject to the QoS requirements.

UTRAN will only support Class A mode of operation

In GERAN Class A mode of operation may be achieved using Dual Transfer Mode (DTM) functionality [10]

Class B: The UE is attached to both GPRS and other services, but the UE can only operate one set of services at a time. When the UE is in both idle mode and packet idle mode it should be able to monitor paging channels for both circuit-switched and packet-switched services depending on the mode of network operation.

At least one mode of network operation shall be defined so that when an UE is in both idle mode and packet idle mode it shall be able to respond to paging for both circuit-switched and packet-switched services. A mode of network operation where the network performs the paging for circuit-switched and packet-switched services on different paging channels is also defined. In such case an UE in both idle mode and packet idle mode should either attempt to listen to both paging channels with priority for the circuit-switched service or revert to class-C mode of operation.

If in a mode of network operation the network performs both the paging for circuit-switched and packet-switched services on the same paging channel, then the UE shall respond to paging messages for both services.

There is no requirement for the UE to monitor the packet paging channel when in dedicated mode.

One mode of network operation shall be defined so that when an UE is engaged in packet data transfer, it shall receive paging messages via the packet data channel without degradation of the packet data transfer. Modes of network operation where paging for other services is not done via the packet data channel are also defined. In such cases an UE engaged in packet data transfer may attempt to receive paging messages.

When responding to a paging message for other services, the UE shall establish the connection for that incoming service (i.e., enter dedicated mode) and suspend GPRS activity. GPRS activity is resumed upon return to idle mode.

If paged for an incoming circuit-switched call, the UE shall indicate the presence of the call to the user or user’s application, and where possible provide to the user the CLI. It shall be possible for the user (or the user’s application) to decide how to proceed with an incoming call (e.g., accept the call, indicate UDUB, or invoke Call Deflection).

It shall be possible for the UE to receive SMS-CB messages if it attached to GPRS but is not engaged in packet data transfer.

Class B is not applicable to UTRAN or GERAN Iu Mode.

NOTE 2: Users should be aware that monitoring paging (in some modes of network operation), responding to paging, alerting of circuit-switched service, or acceptance or establishment of a circuit-switched call during an active GPRS connection may degrade the performance of the established GPRS connection and, in some cases, may cause failures in an application using the GPRS connection (e.g., a file transfer might be aborted due to a timeout of the application protocol).

Class C: The UE is attached to either GPRS or other services. Alternate use only. If both services (GPRS and Circuit Switched) are supported then a Class C UE can make and/or receive calls only from the manually or default selected service, i.e., either GPRS or Circuit Switched service. The status of the service which has not been selected is detached i.e., not reachable. The capability for GPRS-attached class-C UEs to receive and transmit SMS messages is optional.

It shall be possible for the UE to receive SMS-CB messages if it attached to GPRS but is not engaged in packet data transfer.

Class C is not applicable to UTRAN.

An UE may be reconfigured. E.g., a class A UE configured as 1 slot for circuit switched plus 1 slot for GPRS may be reconfigured as a class C configured as 0 slots for circuit switched plus 2 slots for GPRS.

Non-voice only UEs do not have to (but may) support emergency calls.

6.1.2 UE support for SMS over GPRS

The network shall support SMS message reception and transmission for GPRS-attached UEs. However, this feature might not be implemented in all networks.

The following requirements are applicable to class A and class B GPRS UEs:

– If the UE preferred method, at power up or later, is sending SMS over GPRS and this fails, either due to a direct failure indication or rejection, or due to the complete lack of a response, then the UE shall switch to sending subsequent SMS’s by circuit switched services for an implementation dependent time. After this time the UE may again revert to trying to send SMS’s over GPRS.
Also, if a different PLMN is selected the UE shall again revert to trying to send SMS’s over GPRS.

– If the SMS attempt fails on both GPRS and circuit switched services, then the user/toolkit is informed.

6.2 Subscriber roaming

GPRS shall provide the ability for subscribers to access the service while roaming between networks. This implies the pre-existence of an international signalling mechanism and a service agreement between the different network operators involved.

It shall be possible for GPRS subscribers to remain GPRS attached when moving from one PLMN to another.

HSDPA shall be supported when roaming providing a roaming agreement for the necessary transport/bearer service(s) is currently valid.

6.3 Construction of GPRS subscriber numbers

The number of a GPRS subscriber shall be composed such that the PLMN operator can maintain control of the numbering scheme, thereby ensuring subscriber numbering integrity. The ability to allocate a subset of the numbers privately shall be possible.

6.4 Battery life extension

The GPRS service shall provide for a means to extend the battery life of an UE, by allowing the UE to reduce current drain; e.g., by using a discontinuous reception (DRX) strategy. The power conservation strategy should allow the UE to remain in a very low current state for a considerable proportion of the time. Moreover, the power conservation strategy should ensure that no messages are lost and that bandwidth is not wasted.

When conserving power through the use of DRX, or other techniques, the UE shall still meet all QoS requirements of selected classes. Some classes of service may necessitate continuous reception (i.e., no DRX capability).

6.5 Format Of Message User Data

The user data is to be presented as an octet string between GPRS’s access points, and is not interpreted by the PLMN.

6.6 Charging aspects

The charging information that the GPRS network collects for each UE shall be standardised. The information that the operator uses to generate a bill to a subscriber is operator specific. Billing aspects, e.g. a regular fee for a fixed period, are outside the scope of this specification.

The HPLMN Operator/Service Provider may be able to charge the GPRS subscriber for all costs incurred including those costs incurred in an external network be it a VPLMN or a data network.

The charging requirements of HSDPA shall be identical to the existing packet data services.

6.6.1 PTP and IP-M charging information

The charging information of PTP and IP-M services is collected for the GPRS subscriber. As a minimum the following charging information shall be collected:

– destination and source: The charging information shall describe the destination and source addresses;

– usage of radio interface: The charging information shall describe the amount of data transmitted in MO and MT directions categorized with QoS and user protocols;

– usage of the external data networks: The charging information shall describe the amount of data sent/received to/from the external data network;

– usage of the packet data protocol addresses: The charging information shall describe how long the UE has used the packet data protocol addresses;

– usage of the general GPRS resources: The charging information shall describe the usage of other GPRS related resources and UE’s activity in the GPRS network (e.g. Attach/Detach, mobility management);

– location of UE: HPLMN, VPLMN, plus optional higher accuracy location information.

6.6.2 Reverse Charging

It shall be possible to provide reverse charging as a subscription option. However, reverse charging may not be applicable to certain external data network protocols. It shall be possible, as an option, to allow users to roam from one environment to another, between fixed and mobile, between public and private as well as between different public systems.

6.7 Security services

The use of radio communications for transmission to/from subscribers in mobile networks makes them particularly sensitive to:

1) misuse of their resources by unauthorized persons using manipulated UEs;

2) eavesdropping on the information being exchanged on the radio path.

Therefore, to protect the system in the two cases mentioned above, the following security features are provided for GPRS:

– UE authentication; i.e., the confirmation by the land-based part of the system that the subscriber identity, transferred by the UE within the identification procedure on the radio path, is the one claimed. The purpose of this authentication is to protect the network against unauthorized use. It also enables the protection of GPRS subscribers by denying intruders the ability to impersonate authorized users;

– access control; i.e., the network can support restrictions on access by or to different GPRS subscribers, such as restrictions by location, screening lists, and so on;

– user identity confidentiality; i.e., the property that the user identity on the radio link is not made available or disclosed to unauthorized individuals, entities or processes. The purpose is to provide privacy of identities of the subscribers who are using GPRS radio resources. It allows for the improvement of other security features, e.g., user information confidentiality, and also provides for the protection against tracing the location of a mobile subscriber by listening to the signalling exchanges on the radio path;

– user information confidentiality; i.e., the property that the user information is not made available or disclosed to unauthorized individuals, entities or processes. The purpose is to provide for confidentiality of user data, i.e., protection of the message part pertaining to layers 3 and above, that passes over the radio path.

Both user identity and user data shall be protected as shown in table 6:

Table 6: Protection of user identity and user data


User Identity Protection

User Data Protection







Security mechanisms available for existing teleservices and bearer services should be used if possible.

6.8 Message Screening

The message screening function is concerned with filtering out unauthorized or unwanted messages. Message screening may be used to restrict the types of message or the volume of data which may be transferred across the GPRS network to/from an individual subscriber.

6.9 GPRS Operator Determined Barring

GPRS subscribers can request packet oriented services from access points within the HPLMN, or from access points within another GPRS enabled PLMN. Similarly, when roaming, a subscriber may request to be connected to an access point within the HPLMN which requires all of the packets to be sent over an international link, which may attract a higher charge from Service Providers. Therefore, similarly to circuit switched domain, barring capability is required.

The specific requirements for ODB of GPRS can be found in 3GPP TS 22.041 (Operator Determined Barring) [8].