WO2001091499A1

WO2001091499A1 - Modification of an access radio block in a radio communications system in accordance with the geran standard

Info

Publication number: WO2001091499A1
Application number: PCT/DE2001/001973
Authority: WO
Inventors: Carsten Ball; Jean-Michel Traynard
Original assignee: Siemens Aktiengesellschaft
Priority date: 2000-05-22
Filing date: 2001-05-22
Publication date: 2001-11-29
Also published as: AU2001267318A1

Abstract

The invention relates to a method for setting up connections in a radio communications system, especially in a mobile radio telephone system of the second generation GSM. The invention provides that a mobile station signals a support of a standard version to a base station system of the radio communications system in the instance of the connection set-up using a training sequence and of an access radio block. Alternatively, by the selection of the training sequence, the base station system is notified whether a circuit-switched or packet-switched connection should be set up or by a coding or modulation of the access radio block that is different in comparison to other standard versions, the base station is notified of the supported standard version.

Description

MODIFYING AN ACCESS RADIO BLOCK IN A RADIO COMMUNICATION SYSTEM ACCORDING TO THE GERAN STANDARD

The invention relates to a method for establishing a connection in a radio communication system, in particular in a mobile radio system of the second generation GSM.

In radio communication systems, data is transmitted using a radio interface using electromagnetic waves. The radio interface relates to a connection between a base station and subscriber stations, it being possible for the subscriber stations to be mobile stations or fixed radio stations. The electromagnetic waves are emitted with carrier frequencies that lie in the frequency band provided for the respective system. The frequency bands for the known GSM mobile radio system (Global System for Mobile Communications) are, for example, at 900 and 1800 or 1900 MHz.

GERAN (GSM EDGE Radio Access Network) is the ETSI Release 2000 extension for GSM, which is based on the previous ETSI Release 99 EDGE air interface and is intended to achieve convergence with regard to a common UMTS / EDGE network, the so-called core network.

In future there will be cell phone subscribers with "old" cell phones based on Release 99 and even earlier, which only support conventional services, and subscribers with "new" phones based on Release 2000 who want to use the newly defined GERAN real-time services such as "voice over IP" etc. The GERAN network "emulates" the Release 99 functionality in the BSS (base station system) and adds new functionalities, ie the BSS becomes interfaces to the MSC / TRAU via the so-called A interface (A-Interface) and to the 3GSGSN via the corresponding interfaces IU- Have PS or Gb. At GERAN, a new facility with a separate control and user tarpaulin is being created in the BSC (base station control) parallel to the previous CS (circuit switched - circuit switched) and PS (packet switched) units (entities) introduced. Therefore, the BSS, for example in the BSC, previously circuit-switched (CS circuit switched) GSM / HSCSD / ECSD voice and data services (voice and data services), packet-switched (PS packet switched) GPRS / EGPRS data services (data services) as well as GERAN is completely new Support services coming from the UMTS area.

For the BSS or the network, it is now very important to know very early on when establishing a connection or access (ACCESS) of a mobile station (mobile) which type of mobile station it is and which services could possibly be requested. Among other things, this determines which resources are assigned to the mobile station on the air interface, via which device the ACCESS or RESOURCE_REQUEST (request) is processed by the mobile station in the base station system, and via which interface from the base station system to the network the CS or PS -Data are routed.

Here is an example: A GERAN Release 2000 mobile station tries to access the RACH / PRACH (Random Access Channel / Physical Random Access Channel), which is exclusively available for this purpose. On the part of the base station system, the question now arises whether the mobile station uses an SDCCH (Stand Alone Dedicated Control Channel) as a resource. as is known for speech and HSCSD for further signaling, or as is known for GPRS / EGPRS a PDCH (PDTCH, PACCH) is assigned in the so-called assignment. The subsequent allocation of resources is used to negotiate the final allocation of resources (Resource_Request from the mobile station, further assignment from the BSS as an answer), ie TCH (Traffic Channel) for speech or HSCSD, E-TCH for ECSD, PDTCH for GPRS / EDGE, or multislot allocation, quality of service etc.

A great advantage of such a "switch" in the base station controller BSC, which is already made clear with the ACCESS, is that the new GERAN extensions and modifications in the base station system BSS have only a minor influence on the existing GSM / GPRS / EDGE implementation and will allow a clear separation between GERAN user / control plane and GERAN RLC / MAC layer in the future.

The invention is based on the object of specifying a method which enables simple identification of a mobile station according to the supported standard. This object is achieved by the method according to independent claim 1.

The solution according to the invention enables the base station system to determine the type of mobile station as soon as an access radio block (access burst) is received, to select a corresponding device in the base station system and to assign or assign a suitable signaling channel, for example SDCCH or PDTCH / PACCH, through the GERAN control plane to refer to it. To do this, the access channel RACH / PRACH only has to be slightly modified. The well-known GSM / EDGE air interface remains unchanged and compatibility with Release 99 is guaranteed. The well-known GSM network enables access to voice services via an 8 bit access burst in the RACH. The mobile stations use only the training sequence TS "0" defined in the GSM network. The base station controller BSC is known to initiate a circuit switched connection and involves the mobile switching center MSC.

A packet data access (packet data access) takes place for GPRS by means of an 8 bit RACH access radio block if no PBCCH is available, or by means of an 8 bit or 11 bit long access radio block in the PRACH if a PBCCH is available. These access radio blocks also only use the training sequence TS "0".

For the EDGE standard, a new EGPRS_PACKET_CHANNEL_REQUEST in Release 99 was introduced on the PRACH, which uses two new training sequences TS1 and TS2 to characterize the 8PSK capability of the mobile stations. The base station controller is thus aware that a packet-switched connection has been initiated and involves the PCU and the SGSN.

The known coding of the access radio blocks in the RÄCH or PRACH can be found in the standard font GSM 05.03, chapter 4.6 and chapter 5.3.

For the GERAN standard, the access or the access radio block ACCESS on the access channel RACH / PRACH is to be modified such that the base station controller BSC already knows when establishing the connection that a channel specified according to a later release, for example the 2000 release, will be established should. The following configurations according to the invention are proposed for this: 1) ACCESS should be accessed on the RACH. For this purpose, for example, the 8-bit access radio block with the training sequence TS1 is used to establish a circuit-switched (GERAN-CS (Circuit switched)) connection, and the training sequence TS2 is used to transmit a packet-switched (GERAN-PS (packet switched)) ) Establish connection, or vice versa. Both TS1 and TS2 are already specified in the GSM 05 series.

In the example of a circuit-switched GERAN connection shown in FIG. 1, the further signaling is initially carried out via the GERAN Control Plane (C-Plane) in the base station controller and via an SDCCH channel on the radio interface. Then a circuit-switched traffic channel (CS TCH - Circuit Switched Traffic Channel) is set up and the user data from the GERAN User Plane (U-Plane) is transmitted.

In the case of a packet-switched GERAN connection shown by way of example in FIG. 2, further signaling takes place initially via the GERAN Control Plane (C-Plane) and via a PDTCH or PACCH channel on the radio interface. Then one or more PDTCHs are assigned and the packet data from the GERAN User Plane (U-Plane) is transferred.

2) For access to the RÄCH (Random Access Channel), an extended access block with, for example, a length of 11 bits is used, as in the described GPRS or EDGE standard, in order to indicate the GERAN capability of the mobile station with the additional bits. As an alternative to this, the coding of the known 8-bit access radio block can also be modified according to the invention. 3) Additional, alternative training sequences, for example TS3, TS4, etc., are used which indicate to the base station system that a GERAN mobile station is accessing.

4) When accessing via PRACH, further training sequences are used to differentiate from the 8 or 11 bit GPRS / EGPRS PACKET HANNEL_REQUEST described, the coding is changed or an extended training sequence with, for example, 13 bits is introduced. The only disadvantage of this method is that the PRACH is only available if the PBCCH is activated in the radio cell. The RÄCH, however, is always available.

5) According to the invention, an access radio block with a modified modulation is used, for example 8PSK modulation is used instead of the GMSK modulation otherwise used. This also triples the number of available information bits in the access radio block, which enables a better differentiation without additional signaling load through extended training sequences.

The availability of the new GERAN access radio block in a radio cell is displayed to the mobile stations in system information messages broadcast on a PBCCH or BCCH channel by the network.

In the case of the so-called EDGE Compact system based on the IS-136 standard, which has no RÄCH, the access radio block should be modified on the CPRACH. The availability of the access radio block according to the invention is displayed on a CPBCCH channel.

Claims

claims

1. A method for establishing a connection in a radio communication system, in which a mobile station signals support of a standard version of a base station system of the radio communication system when a connection is established by means of a training sequence and an access radio block, the choice of the training sequence indicating to the base station system whether a circuit-switched one - or a packet-switched connection is to be set up.

2. Method for establishing a connection in a radio communication system, in which a mobile station signals support of a standard version to a base station system of the radio communication system when a connection is established by means of a training sequence and an access radio block, the coding of the Access radio blocks the base station system the supported standard version is displayed.

3. Method for establishing a connection in a radio communication system, in which a mobile station signals support of a standard version of a base station system of the radio communication system when a connection is established by means of a training sequence in an access radio block, with a different modulation of the access radio block compared to other standard versions The supported standard version is displayed on the base station system.

4. The method according to claim 3, in which an 8PSK modulation is used for the access radio block as the modulation.

5. The method according to any one of the preceding claims, wherein the radio communication system supports a GERAN standard.

6. The method according to any one of the preceding claims, in which different devices are used in the base station system depending on the signaled support of a standard version.