Abis interface channel assignment

Abis interface has three types of channels, including Traffic Channel (TCH), Radio Signaling Link (RSL) and Operation & Maintenance Link (OML). Each site corresponds to an OML, each TRX corresponds to an RSL, and a radio traffic channel corresponds to the traffic channel at the Abis interface.

There are three multiplexing modes for Abis interface: 10:1, 12:1 or 15:1, respectively meaning that the data of 10, 12 or 15 TRXs can be simultaneously transmitted on one E1.

In the following description, the row is the timeslot No., and the column is the sub-timeslot No. Which is calculated by 8kbit/s rate. Ti.j refers to the No. j sub-timeslot of the No. i TRX which occupies a 16kbit/s sub-timeslot on E1.

Timeslot distribution of E1 in 10:1 multiplexing

Table 1 Sequence table under 10:1 mode

Sub-TS TS Sub-TS 0 Sub-TS1 Sub-TS2 Sub-TS3

0 Synchronization

1 T0.0 T0.1 T0.2 T0.3

2 T0.4 T0.5 T0.6 T0.7

3 RSL0

4 T1.0 T1.1 T1.2 T1.3

5 T1.4 T1.5 T1.6 T1.7

6 RSL1

7 T2.0 T2.1 T2.2 T2.3

8 T2.4 T2.5 T2.6 T2.7

9 RSL2

10 T3.0 T3.1 T3.2 T3.3

11 T3.4 T3.5 T3.6 T3.7

12 RSL3

13 T4.0 T4.1 T4.2 T4.3

14 T4.4 T4.5 T4.6 T4.7

15 RSL4

16 T5.0 T5.1 T5.2 T5.3

17 T5.4 T5.5 T5.6 T5.7

18 RSL5

19 T6.0 T6.1 T6.2 T6.3

20 T6.4 T6.5 T6.6 T6.7

21 RSL6

22 T7.0 T7.1 T7.2 T7.3

23 T7.4 T7.5 T7.6 T7.7

24 RSL7

25 T8.0 T8.1 T8.2 T8.3

26 T8.4 T8.5 T8.6 T8.7

27 RSL8

28 T9.0 T9.1 T9.2 T9.3

29 T9.4 T9.5 T9.6 T9.7

30 RSL9

31 OML

 

In 10:1 multiplexing, each E1 carries 10 TRXs.Each signaling link occupies a 64kbit/s timeslot on the E1.If some sites cascad on one E1, , the E1 can carry 4 sites/9 TRXs or 7 sites/8 TRXs.

Timeslot distribution of E1 in 12:1 multiplexing

Table 2 Sequence table under 12:1 mode

Sub-TS TS Sub-TS 0 Sub-TS1 Sub-TS2 Sub-TS3

0 Synchronization

1 T0.0 T0.1 T0.2 T0.3

2 T0.4 T0.5 T0.6 T0.7

3 RSL0, RSL1

4 T1.0 T1.1 T1.2 T1.3

5 T1.4 T1.5 T1.6 T1.7

6 T2.0 T2.1 T2.2 T2.3

7 T2.4 T2.5 T2.6 T2.7

8 RSL2, RSL3

9 T3.0 T3.1 T3.2 T3.3

10 T3.4 T3.5 T3.6 T3.7

11 T4.0 T4.1 T4.2 T4.3

12 T4.4 T4.5 T4.6 T4.7

13 RSL4, RSL5

14 T5.0 T5.1 T5.2 T5.3

15 T5.4 T5.5 T5.6 T5.7

16 T6.0 T6.1 T6.2 T6.3

17 T6.4 T6.5 T6.6 T6.7

18 RSL6, RSL7

19 T7.0 T7.1 T7.2 T7.3

20 T7.4 T7.5 T7.6 T7.7

21 T8.0 T8.1 T8.2 T8.3

22 T8.4 T8.5 T8.6 T8.7

23 RSL8, RSL9

24 T9.0 T9.1 T9.2 T9.3

25 T9.4 T9.5 T9.6 T9.7

26 T10.0 T10.1 T10.2 T10.3

27 T10.4 T10.5 T10.6 T10.7

28 RSL10, RSL11

29 T11.0 T11.1 T11.2 T11.3

30 T11.4 T11.5 T11.6 T11.7

31 OML

In 12:1 mode, each E1 carries 12 TRXs, and every two RSLs share a 64kbit/s timeslot of E1. If some site cascaded on one E1, then the E1 can carry 3 sites/11 TRXs or 6 sites/10 TRXs.

Timeslot distribution of E1 in 15:1 multiplexing

Table 3 Sequence under 15:1 mode

Sub-TS TS Sub-TS 0 Sub-TS1 Sub-TS2 Sub-TS3

0 Synchronization 

1 V1 V2 V3 V4 

2 V5 V6 V7 V8 

3 V9 V10 V11 V12 

4 V13 V14 V15 V16 

5 V17 V18 V19 V20 

6 V21 V22 V23 V24 

7 V25 V26 V27 V28 

8 V29 V30 V31 V32 

9 V33 V34 V35 V36 

10 V37 V38 V39 V40 

11 V41 V42 V43 V44 

12 V45 V46 V47 V48 

13 V49 V50 V51 V52 

14 V53 V54 V55 V56 

15 V57 V58 V59 V60 

16 V61 V62 V63 V64 

17 V65 V66 V67 V68 

18 V69 V70 V71 V72 

19 V73 V74 V75 V76 

20 V77 V78 V79 V80 

21 V81 V82 V83 V84 

22 V85 V86 V87 V88 

23 V89 V90 V91 V92 

24 V93 V94 V95 V96 

25 V97 V98 V99 V100 

26 V101 V102 V103 V104 

27 V105 V106 V107 V108 

28 RSL11, 12, 13, 14 

29 RSL7, 8, 9, 10 

30 RSL3, 4, 5, 6 

31 OML+RSL0, 1, 2 

In 15:1 mode, each E1 carries 15 TRXs, and timeslots 1 to 27 contain 108 sub-timeslots of 16kbit/s for the use by traffic channels of 15 TRXs. Vi refers to the ith traffic channel of the site. The E1 can be configured with 16 signaling links, every 4 of which share a 64kbit/s timeslot. If all cascaded sites have the same 15:1 configuration, then a single E1 can carry 2 sites/14 TRXs or 4 sites/12 TRXs.