10 THE RA1’/RAA’ FUNCTION

08.203GPPRate Adaptation on the Base Station System - Mobile Service Switching Centre (BSS-MSC) InterfaceTS

The RA1’/RAA’ shall be applied only when TCH/F14.4, TCH/F28.8, or TCH/F43.2 channel coding is used. The RA1/RAA’ converts 290-bit blocks from the channel coder or EDGE multiplexing function into E-TRAU frames and vice versa. The format of E-TRAU frame is specified in 3GPP TS 08.60.

The RA1’/RAA’ function in the BSS shall be applied on each of the n substreams and there are no significant differences between the single slot case and the multislot case. The table below gives a relation between the AIUR, channel coding and number of substreams. As an example from table 2 : The wanted AIUR is 28,8 kbit/s, the number of substreams needed to support this rate is 2. Each individual substream shall be rate adapted as in the single slot case.

Table 2 Relationship between AIUR, channel coding and number of channels.

AIUR

Transparent

Non-transparent

14,4 kbit/s

1

1

28,8 kbit/s

2

2

38,4 kbit/s

3

N/A

43,2 kbit/s

N/A

3

48 kbit/s

4

N/A

56 kbit/s

4

N/A

57,6 kbit/s

N/A

4

64 kbit/s

5

N/A

10.1 Radio Interface rate of 14,5 kbit/s

See 3GPP TS 08.60.

10.2 Synchronisation

See 3GPP TS 08.60.

10.3 Idle frames

See 3GPP TS 08.60.