Browse Prior Art Database

Optimized Call Set Up for the CS Service Enabling Hand Over

IP.com Disclosure Number: IPCOM000167067D
Published in the IP.com Journal: Volume 8 Issue 2A (2008-02-14)
Included in the Prior Art Database: 2008-Feb-14
Document File: 3 page(s) / 53K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

The 3rd Generation Partnership Project (3GPP) is a worldwide cooperation for standardizing the mobile communication through UMTS and GMS technology. There are many technical specification groups such as the "Technical Specification Group Radio Access Network" (TR 25.999). In the specification "TR 25.999 HSPA evolution" (version 2.2.0 and higher) a solution for CS service enabling handover is defined (see Fig. 1), where the evolved HSPA Node B is connected to the RNC via Iur. Iur is an interface located on a UMTS network. It is found between two RNCs. The evolved HSPA Node B includes PS RNC functionality and CS calls are handled via RNC. In case of the packet switched service, only RAN supports Iu-CS signaling in a dedicated carrier scenario. In TR 25.999 it is described how the RRC connected terminal is relocated to RNC (using SRNS relocation).

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Optimized Call Set Up for the CS Service Enabling Hand Over

Idea: Tuomo Flytström, FI-Espoo; Petri Jäppilä, FI-Espoo

The 3rd Generation Partnership Project (3GPP) is a worldwide cooperation for standardizing the mobile communication through UMTS and GMS technology. There are many technical specification groups such as the "Technical Specification Group Radio Access Network" (TR 25.999).

In the specification "TR 25.999 HSPA evolution" (version 2.2.0 and higher) a solution for CS service enabling handover is defined (see Fig. 1), where the evolved HSPA Node B is connected to the RNC via Iur. Iur is an interface located on a UMTS network. It is found between two RNCs. The evolved HSPA Node B includes PS RNC functionality and CS calls are handled via RNC. In case of the packet switched service, only RAN supports Iu-CS signaling in a dedicated carrier scenario. In TR 25.999 it is described how the RRC connected terminal is relocated to RNC (using SRNS relocation).

The problem with this solution is that it creates SRNC relocation towards the MSC which is not needed.

In the following, it is proposed that the evolved Node B forwards the initial UE message to the RNC, so that the CS signaling can be established directly to the RNC via MSC (see Fig. 2). This is favorable if PS RAB exists and SGSN can be used for relocation.

In the CS service enabling HO, the proposed idea removes the additional SRNS relocation in the CS domain (e.g. MSC). Moreover, call set up will become fast. In a practical realization, the initial direct message can be transmitted, e.g. in uplink signaling transfer indication.

Acronyms:
CS: Circuit Switched
GMS: Global System for Mobile Communications
GPRS: General Packet Radio Service
HSPA: High Speed Packet Access
Iu: Interface in UMTS which links the RNC wi...