6 Compatibility issues; interaction with other GSM services

03.633GPPPacket Data on Signalling channels service (PDS) Service description, Stage 2TS

6.1 Use of PDS in parallel to basic services

[NOTE: Interaction with other phase 2+ basic services has to be elaborated.]

Parallel use of PDS and short message cell broadcast service (TS 23) is not required. There may, however, be Mobile Stations allowing parallel use, possibly depending on the channel used for the RR connection and SMSCB.

For all other basic services (all requiring an CM connection). i.e. TS 11, 12, 21, 22, 61, 62, BS 21-26, BSĀ 31-34, BS 41-46, BS 51-53, 81, the following applies:

Mobile originating basic service: There is no restriction for a mobile originating CM connection establishment and following use of the basic service in parallel to a PDS connection.

Mobile terminating basic service: During the establishment phase and release phase of an RR connection, there is a time when the mobile station is not pageable and where the MSC cannot transfer the information about the MT CM connection to be established to the MS. In most cases, the information can be transferred with delay. With the resulting exceptions, there is no restriction for a mobile terminating CM connection establishment and following use of the basic service in parallel to a PDSS1 connection.

While a Mobile Station is engaged in a PDSS2 service, the mobile subscriber may appear to the network as not reachable:

a) When a mobile station uses PDSS2 and an MM connection exists, the MSC may initiate the CM connection establishment on the used RR connection.

b) When a mobile station uses PDSS2 and no MM connection exists, there are three possible situations:

1) The MS is establishing an RR connection. In this situation the MS doesn’t listen to its paging subchannel.

2) An RR connection is established, and the mobile station can listen to its paging subchannel without restriction to transmission on the RR connection (depending on the MS capabilities and the channel configuration). In this case the mobile station shall listen to the paging subchannel.

3) An RR connection is established, and the mobile station can listen to its paging subchannel with restriction to transmission on the RR connection (depending on the MS capabilities and the channel configuration). In this case the mobile station may be configured to listen to the paging subchannel or not, possibly depending on the rate of missed signalling frames (including idle frames; in this case the channel is in signalling only mode).

In any case, if the MS receives a paging, it shall send a PAGING RESPONSE message on the RR connection in use. The BSS shall use the PAGING RESPONSE as initial L3 message to the MSC.

6.2 Interaction between PDS and supplementary services

Supplementary services are not applicable to PDS; they may be applicable to an application using PDS.

There is interaction between PDS and call offering supplementary services applied to other basic services: It is not predictable whether an MS engaged in a PDSS2 connection appear to the network as not reachable. In that case, CFNRc could become applicable.