A.2 Implementation options for TCH channels
3GPP45.002GSM/EDGE Multiplexing and multiple access on the radio pathRelease 17TS
A.2.1 C0 filling on the TCH
When the TCH is active, and no associated traffic frame is scheduled for transmission, the following options apply for filling the burst on the C0 radio frequency channel.
A.2.1.1 A dummy burst with (BN61, BN62, BN86) = training sequence bits of normal bursts
A.2.1.2 A dummy burst with the "C0 filling training sequence
(BN61, BN62, BN86) = (0,1,1,1,0,0,0,1,0,1,1,1,0,0,0,1,0,1,1,1,0,0,0,1,0,1).
A.2.1.3 A dummy burst with ( BN61, BN62, BN86) mapped from the TSC bits of normal bursts according to the table
|
TSC from TSC set 1 for other bursts on TCH |
Dummy bursts (BN61, BN62 BN86) |
Corresponding TSC from TSC set 1 |
|
0 |
(0,1,0,0,0,0,1,1,1,0,1,1,1,0,1,0,0,1,0,0,0,0,1,1,1,0) |
2 |
|
1 |
(0,1,0,0,1,1,1,0,1,0,1,1,0,0,0,0,0,1,0,0,1,1,1,0,1,0) |
5 |
|
2 |
(0,0,1,0,0,1,0,1,1,1,0,0,0,0,1,0,0,0,1,0,0,1,0,1,1,1) |
0 |
|
3 |
(0,0,0,1,1,0,1,0,1,1,1,0,0,1,0,0,0,0,0,1,1,0,1,0,1,1) |
4 |
|
4 |
(0,1,0,0,1,1,1,0,1,0,1,1,0,0,0,0,0,1,0,0,1,1,1,0,1,0) |
5 |
|
5 |
(0,1,0,0,0,0,1,1,1,0,1,1,1,0,1,0,0,1,0,0,0,0,1,1,1,0) |
2 |
|
6 |
(0,1,0,0,0,1,1,1,1,0,1,1,0,1,0,0,0,1,0,0,0,1,1,1,1,0) |
3 |
|
7 |
(0,1,0,0,1,1,1,0,1,0,1,1,0,0,0,0,0,1,0,0,1,1,1,0,1,0) |
5 |
A.2.1.4 Partial SID information
The BTS transmits bursts containing parts of the SID frames provided by the speech encoder. The bits transmitted in such bursts on C0 carrier contain the same bits that would have been transmitted in those bursts in those if the associated traffic frames were scheduled for transmission.
A.2.2 Half burst filling
For downlink DTX, when a given traffic frame is scheduled for transmission and one of its adjacent traffic frames is not scheduled for transmission, half of the "encrypted bits" belonging to the normal bursts associated with the scheduled traffic frame need to be filled. These bits are referred to as "half burst filling bits". These half bursts filling bits contain either.
A.2.2.1 Partial SID information from any associated SID frame; or
A.2.2.2 The mixed bits of the dummy bursts (encrypted or not encrypted)
A.2.3 Dummy burst Stealing flag
The dummy burst stealing flag are set to either 1 or 0.
A.2.4 Half burst Filling Stealing flag
BN60 or BN87 corresponding to the "encrypted bits" of a filled half burst, defined as the "half burst filling stealing flag", are jointly set to a value of either 1 or 0.
A.2.5 Allowed combinations
Table A.2.5.1 below provides the allowed combinations for phase 1 networks supporting downlink DTX in conjunction with frequency hopping.
Table A.2.5.1: Possible combinations for networks supporting downlink DT
in conjunction with frequency hopping
|
Combination |
C0 filling on the TCH |
Half Burst filling |
Dummy Bursts Stealing Flag |
Half Burst Filling Stealing Flag |
|
1 |
Dummy bursts with (BN61‑BN86) equal to the bits of the TSC of the other normal bursts (A 2.1.1) |
not defined |
0 |
0 |
|
2 |
Dummy burst with "C0 filling training sequence" (A 2.1.2) |
Partial SID information (A 2.2.1) |
0 |
0 |
|
3 |
Dummy burst with (BN61, BN62….BN86) mapped from the TSC bits of normal bursts (A 2.1.3) |
Partial SID information (A 2.2.1) |
0 |
0 |
|
4 |
Partial SID information (A 2.1.4) |
Partial SID information (A 2.2.1) |
1 |
1 |
|
5 |
Dummy burst with "C0 filling training sequence" (A 2.1.2) |
Dummy burst mixed bits (A 2.2.2) |
1 |
1 |
|
6 (for DCS 1 800 only) |
Partial SID information (A 2.1.4) |
Partial SID information (A 2.2.1) |
0 |
0 |