10 The Functions RA1’/RAA’ and RA1’/RAA"
3GPP48.020Rate adaption on the Base Station System - Mobile-services Switching Centre (BSS - MSC) interfaceRelease 17TS
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 48.060.
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.
For the AIURs of 64 kbit/s, RA1’/RAA” shall be applied as specified in 3GPP TS 44.021. This function converts 290-bit blocks from the channel coder directly into the synchronous 64 kbit/s data stream, an E-TRAU frame is not created in this case.
The table 2 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 48.060.
10.2 Synchronisation
See 3GPP TS 48.060.
10.3 Idle frames
See 3GPP TS 48.060.