Content for TR 43.901 Word version: 18.0.0

3.1 Definitions 3.2 Symbols 3.3 Abbreviations
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0 Introduction p. 5

This document captures the results of the feasibility study of enabling generic access to A/Gb interface using alternate access means such as ADSL, Cable, Bluetooth, etc. Mobile stations obtain services from the GSM core network using such generic access means rather than through the traditional GERAN radio interface. The goal is to ensure no impact to the current A/Gb interface specifications.

1 Scope p. 6

This document studies the feasibility of generic access to A/Gb interface. Specific areas of study are:

Architecture to enable generic access.
Access interface protocols required to provide connectivity to A/Gb interface and GSM/GPRS services.
Security mechanisms to support generic access architecture.
Determining feasibility for support of services currently supported through GERAN.

The focus of the study shall be on establishing the feasibility for supporting generic access in the home network case, while also identifying issues with extending the solution to the roaming scenarios.

2 References p. 6

The following documents contain provisions, which, through reference in this text, constitute provisions of the present document.

References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

[1]

TS 22.011: "Service accessibility".

[2]

TS 23.234: "3GPP system to Wireles Local Area Network (WLAN) interworking; System description".

[3]

TS 26.103: "Speech codec list for GSM and UMTS".

[4]

ITU T Recommendation V.110: "Support by an ISDN of data terminal equipments with V-Series type interfaces".

[5]

RFC 791: "Internet Protocol".

[6]

RFC 793: "Transmission Control Protocol".

[7]

RFC 2406: "IP Encapsulating Security Payload (ESP)".

[8]

IKEv2

[9]

EAP SIM

[10]

IPSec NAT

[11]

RFC 768: "User Datagram Protocol".

[12]

RFC 3550: "A Transport Protocol for Real-Time Applications".

[13]

TS 33.234: "3G security; Wireless Local Area Network (WLAN) interworking security".

[14]

RFC 2406: " IP Encapsulating Security Payload (ESP)".

[15]

TS 23.122: "Non-Access-Stratum functions related to Mobile Station (MS) in idle mode".

3 Definitions, symbols and abbreviations p. 7

3.1 Definitions p. 7

For the purposes of the present document, the following terms and definitions apply.

Generic Access Network:

an access network providing access to A/Gb interfaces using broadband IP network.

Generic Access Network Controller:

the network node that connects to the MSC and SGSN via the A-interface and Gb interface respectively and mimics the functionality of the GERAN BSS.

Roving:

the action of re-selection between 3GPP access technology and GAN for a mobile station in idle mode.

Rove in:

the mobile station reselects from GERAN/UTRAN to GAN.

Rove out:

the mobile station reselects from GAN to GERAN/UTRAN.

Handover:

a mobile station engaged in a call moves between GERAN/UTRAN and GAN.

Handover in:

the mobile station moves from GERAN/UTRAN to GAN.

Handover out:

the mobile station moves from GAN to GERAN/UTRAN.

Seamless:

free from noticeable transitions (i.e., no end-user action is required; speech interruptions are short; service interruptions are short; incoming calls are not missed; packet sessions are maintained; services work identically).

3.2 Symbols p. 7

For the purposes of the present document, the following symbols apply:

GSM A Interface: the A interface is located between the MSC (Mobile service Switching Centre) and the BSS (Base station system or radio Sub-System).

GSM Gb Interface: the Gb interface connects the Base Station System (BSS) to the Serving GPRS Support Node (SGSN)

Interface between MS and GAN

Reference point between a Packet Data Gateway and a 3GPP AAA Server or 3GPP AAA proxy

3.3 Abbreviations p. 7

For the purposes of the present document, the following abbreviations apply:

A-GPS

Assisted-GPS

AAA

Authentication, Authorisation and Accounting

ADSL

Asymmetric Digital Subscriber Line

ARFCN

Absolute Radio Frequency Channel Number

BCCH

Broadcast Control CHannel

BSIC

Base transceiver Station Identity Code

BSS

Base Station Subsystem

BSSAP

Base Station Subsystem Application Part

BSSGP

Base Station Subsystem GPRS Protocol

BSSMAP

Base Station Subsystem Management Application Part

CBS

Cell Broadcast Service

Call Control

CGI

Cell Global Identity

Cell Identity

Connection Management

Core Network

Circuit Switched

DSL

Digital Subscriber Line

DTAP

Direct Transfer Application Part

DTM

Dual Transfer Mode

ESP

Encapsulating Security Payload

FFS

For Further Study

GAN

Generic Access Network

GANC

Generic Access Network Controller

GERAN

GSM EDGE Radio Access Network

GMM

GPRS Mobility Management

GMMRR

GPRS Mobility Management Radio Resource

GRR

GPRS Radio Resource

HLR

Home Location Register

Handover

HPLMN

Home Public Land Mobile Network

HTTP

Hyper Text Transfer Protocol

IMS

IP Multimedia Subsystem

IMSI

International Mobile Subscriber Identity

Internet Protocol

Layer 1 (physical layer)

Location Area

Location Area Identity

LCS

Location Services

LLC

Logical Link Control

MAC

Medium Access Control (protocol layering context)

MBMS

Multimedia Broadcast and Multicast Service

Man Machine

MMI

Man Machine Interface

MMS

Multimedia Messaging Service

Mobile Originated

Mobile Station

MSC

Mobile Switching Centre

MVNO

Mobile Virtual Network Operator

NACC

Network Assisted Cell Change

NAS

Non-Access Stratum

NC2

Network Control mode 2

OTDOA

Observed Time Difference Of Arrival (positioning method)

PCM

Pulse Code Modulation

PDP

Packet Data Protocol

PDU

Protocol Data Unit

PLMN

Public Land Mobile Network

Packet Switched

RAN

Radio Access Network

Radio Resources

RRC

Radio Resource Control

RTCP

Real-Time Transport Control Protocol

RTP

Real Time Protocol

SAP

Service Access Point

SAPI

Service Access Point Identifier

SCCP

Signalling Connection Control Part

SGW

Security Gateway

SGSN

Serving GPRS Support Node

SID

SIlence Descriptor

SIM

GSM Subscriber Identity Module

Session Management

SMS

Short Message Service

Supplementary Service

SSL

Secure Sockets Layer

TBF

Temporary Block Flow

TCP

Transmission Control Protocol

TFO

Tandem Free Operation

TLLI

Temporary Logical Link Identity

TMSI

Temporary Mobile Subscriber Identity

TrFO

Transcoding Free Operation

UDP

User Datagram Protocol

UNC

Universal Naming Convention

UTRAN

Universal Terrestrial Radio Access Network

VBS

Voice Broadcast Service

VGCS

Voice Group Call Service

VPLMN

Visited Public Land Mobile Network

4 Assumed high level requirements p. 9

This clause summarizes the various assumed requirements for the feasibility study, when providing generic access to A/Gb interfaces:

GAN interfaces to the core network shall use existing standard A interface to the MSC and Gb interface to the SGSN. Non-access stratum (NAS) protocols shall not be impacted.
GAN shall reuse the existing GERAN identifiers toward the core network.
GAN should support all telecommunication services supported using the A/Gb interfaces.
GAN shall be able to operate over existing generic IP access networks (e.g. Cable, DSL, etc.). GAN-specific functionality shall not be required in the generic IP access network.
Multi-mode terminals shall be able to perform automatic roving between GERAN/UTRAN and GAN, subject to the policies of the operator.
Multi-mode terminals shall be able to perform seamless handover between GERAN/UTRAN and GAN, subject to the policies of the operator.
PLMN selection and mechanisms for the avoidance of ping-pong between GERAN/UTRAN and GAN modes shall follow the principles enunciated in TS 22.011.
The home operator providing GAN service shall control access to Generic Access in all scenarios, including roaming.
GAN shall provide security at least as good as GERAN for all traffic between mobile station and GANC. This includes support of bilateral authentication and encryption of all signalling and user plane traffic between mobile station and GANC.
GAN should not require any change to existing standards e.g. the behaviour of MS in GERAN. Non-GAN capable MSs shall not be impacted due to GAN deployment.
GAN shall be easily scaled with increasing users and traffic. It should efficiently use the resources of the generic IP access network.
Existing charging mechanisms should be used for GAN.