8 The EDGE Multiplexing Function

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

In EDGE configurations where the number of radio interface channels and number of channels or substreams used between BTS and MSC do not match, a multiplexing function described below shall be used at BTS to perform data multiplexing/demultiplexing between the radio interface and network channel configurations. A similar functionshall be used also at MS as described in 04.21.

The EDGE multiplexing function is located between the radio interface and RA1’/RAA’ function.

8.1 Transparent services

TCH/F28.8;

Uplink direction

Refer to the description of corresponding downlink procedures in 3GPP TS 04.21. Two TCH/F14.4 substreams are forwarded towards the MSC as in a 2TCH/F14.4 multislot connection.

Downlink direction

The multiplexing function combines the data received through the two TCH/F14.4 substreams into the 29.0 kbit/s radio interface channel. Refer to the description of corresponding uplink procedures in 3GPP TS 04.21.

TCH/F32.0

Uplink direction

The multiplexing function maps the data received from the radio interface into one 64 kbit/s channel so that data carried by timeslot a (0a6) precedes data carried by timeslot a+n (1a+n7)  the timeslots belonging to one TDMA-frame.

Downlink direction

The multiplexing function distributes the data received from the 64 kbit/s channel into two 32.0 kbit/s radio interface channels so that 640-bit data blocks are allocated to timeslots a (0a6) and a+n (1a+n7). In the datastream, data carried by timeslot a precedes data carried by timeslot a+n of the same TDMA-frame.

8.2 Non-Transparent services

TCH/F28.8;

Uplink direction

The multiplexing function demultiplexes the data received through the 29.0 kbit/s radio interface channel into two TCH/F14.4 substreams. Two 290-bit blocks carrying the two halves of one RLP frame belong to the same substream. Refer to the corresponding downlink procedures in 3GPP TS 04.21.

Downlink direction

The multiplexing function multiplexes the 290-bit blocks received through two TCH/F14.4 substreams into the 29.0 kbit/s radio interface channel. Refer to the corresponding uplink procedures in 3GPP TS 04.21.

TCH/F43.2;

Uplink direction

The multiplexing function demultiplexes the data received through the 43.5 kbit/s radio interface channel into three TCH/F14.4 substreams. Two 290-bit blocks carrying the two halves of one RLP frame belong to the same substream. Refer to the corresponding downlink procedures in 3GPP TS 04.21.

Downlink direction

The multiplexing function multiplexes the 290-bit blocks received through three TCH/F14.4 substreams into the 43.5 kbit/s radio interface channel. Refer to the corresponding uplink procedures in 3GPP TS 04.21.