1 Scope

04.563GPPGSM Cordless Telephony System (CTS), (Phase 1) CTS Radio Interface Layer 3 SpecificationTS

The present document specifies the procedures used at the CTS radio interface (Reference Point Um*, see GSM 03.56) for Call Control (CC), Mobility Management (MM), Radio Resource (RR).

When the notations for "further study" or "FS" or "FFS" are present in the present document they mean that the indicated text is not a normative portion of the present document.

These procedures are defined in terms of messages exchanged over the control channels of the radio interface. The CTS control channels are described in GSM 03.52.

The structured functions and procedures of this protocol and the relationship with other layers and entities are described in general terms in GSM 04.07.

1.1 Scope of the Technical Specification

The procedures currently described in the present document are for the call control of circuit-switched connections, mobility management and radio resource management for circuit-switched services over the CTS radio interface.

GSM 04.10 contains functional procedures for support of supplementary services.

GSM 04.11 contains functional procedures for support of point-to-point short message services.

NOTE: "layer 3" includes the functions and protocols described in the present document. The terms "data link layer" and "layer 2" are used interchangeably to refer to the layer immediately below layer 3.

1.2 Application to the interface structures

The layer 3 procedures apply to the interface structures defined in GSM 04.03. They use the functions and services provided by layer 2 defined in GSM 04.05 and GSM 04.06. GSM 04.07 gives the general description of layer 3 including procedures, messages format and error handling.

1.3 Structure of layer 3 procedures

A building block method is used to describe the layer 3 procedures.

The basic building blocks are "elementary procedures" provided by the protocol control entities of the three sublayers, i.e. radio resource management, mobility management and connection management sublayer.

Complete layer 3 transactions consist of specific sequences of elementary procedures. The term "structured procedure" is used for these sequences.

1.4 Test procedures

Test procedures of the GSM-CTS radio interface signalling are described in GSM 11.10 and GSM 11.56 series.

1.5 Use of logical channels

The logical control channels are defined in GSM 03.52. In the following those control channels are considered which carry signalling information or specific types of user packet information: [to be completed]

i) CTS Beacon CHannel (CTSBCH): downlink only, used to broadcast Cell specific information and fixed part identification information;

ii) CTS Paging CHannel (CTSPCH): downlink only, used to send page requests to Mobile Stations (MSs);

iii) CTS Access Random CHannel (CTSARCH): uplink only, used to request a Dedicated Control CHannel;

iv) CTS-Access Grant CHannel (CTSAGCH): downlink only, used to allocate a Dedicated Control CHannel;

v) Fast Associated Control CHannel (FACCH): bi-directional, associated with a Traffic CHannel;

vi) Slow Associated Control CHannel (SACCH): bi-directional, associated with a Traffic CHannel;

Two service access points are defined on signalling layer 2 which are discriminated by their Service Access Point Identifiers (SAPI) (see GSM 04.06):

i) SAPI 0: supports the transfer of signalling information including user-user information;

ii) SAPI 3: supports the transfer of user short messages.

Layer 3 selects the service access point, the logical control channel and the mode of operation of layer 2 (acknowledged, unacknowledged or random access, see GSM 04.05 and GSM 04.06) as required for each individual message.

1.6 Overview of control procedures

1.6.1 List of procedures

The following procedures are specified in the present document:

a) Clause 4 specifies elementary procedures for Radio Resource management:

– Idle mode procedures (subclause 4.2)

– alive check procedure (subclauses 4.2.1.2 and 4.2.2.3)

– BCH information broadcasting (subclause 4.2.2.1)

– CCH information broadcasting (subclause 4.2.2.2)

– hunting (subclause 4.2.2.4)

– connectionless group alerting (subclause 4.2.2.5)

– RR connection establishment (subclause 4.3)

– entering the dedicated mode: immediate assignment procedure (subclause 4.3.1.1)

– paging procedure for RR connection establishment (subclause 4.3.2)

– Procedures in dedicated mode (subclause 4.4)

– intracell change of channels (subclause 4.4.4)

– channel mode change procedure (subclause 4.4.6)

– ciphering mode setting procedure (subclause 4.4.7)

– RR connection release (subclause 4.4.13)

b) Clause 5 specifies elementary procedures for CTS-Mobility Management

– mobility management common procedures (subclause 5.2)

– CTS attach procedure (subclause 5.2.1)

– CTS periodic attach updating procedure (subclause 5.2.2)

– CTS detach procedure (subclause 5.2.3)

– CTS de-enrolment procedure (subclause 5.2.4)

– CTS mutual authentication procedure (subclause 5.2.5)

– CTS-MSI update procedure (subclause 5.2.6)

– mobility management specific procedures (subclause 5.3)

– CTS enrolment procedure (subclause 5.3.1)

– CTS de-enrolment procedure (subclause 5.3.2)

c) Clause 6 specifies CTS specific elementary procedure for circuit switched Call Control:

– signalling procedures during the active state

– hook flash procedure (subclause 6.1.2)

The elementary procedures can be combined to form structured procedures. Examples of such structured procedures are given in clause 7. This part of the Technical Specification is only provided for guidance to assist implementations.

Clause 8 specifies actions to be taken on various error conditions and also provides rules to ensure compatibility with future enhancements of the protocol.

1.7 Applicability of implementations

The applicability of procedures of the present document for the mobile station is dependent on the services and functions which are to be supported by a mobile station.