Abis TS required for fixed number of Channels in GSM for Huawei system

[aguntuk]

Hi,
I have some queries about Abis Timeslot. How many Abis Timeslot (16K) is required for fixed number of TCH (HR or FR), PDTCH & SDCCH/ MBCCH in GSM for Huawei 3900BTS/3012BTS in BSC6900. Actually, I want to know the calculation process about how can I calculate the required number of Abis Timeslot (16K) for given number of TCH (HR or FR), PDTCH & SDCCH/ MBCCH in GSM for Huawei system. If any doc is there, it will be helpful also.

Thanks in advance. Hope experts can help me out.

[RF engineer]

Hi,
I have some queries about Abis Timeslot. How many Abis Timeslot (16K) is required for fixed number of TCH (HR or FR), PDTCH & SDCCH/ MBCCH in GSM for Huawei 3900BTS/3012BTS in BSC6900. Actually, I want to know the calculation process about how can I calculate the required number of Abis Timeslot (16K) for given number of TCH (HR or FR), PDTCH & SDCCH/ MBCCH in GSM for Huawei system. If any doc is there, it will be helpful also.

Thanks in advance. Hope experts can help me out.

Site Configuration S4/4/4 need number of Abis Sub-timeslot allocation as below.
OML needs 1 timeslot (64kbps) = 4 sub timeslots (16kbps)
RSL for S4/4/4 = 6 timeslots (64kbps) = 24 sub timeslots (16kbps)
TCH for S4/4/4 = (12 TRXs x 8 TCHs) – (3 BCCHs) – (6 SDCCHs) = 87 sub


For MCS-9 needs 3 Idle Timeslot per 1 PDCH
Mostly cells have 3 PDCHs (1 PDTCH + 2 Dynamic PDCHs)
Total Idle Timeslot per site needed = 3 cells x 3 PDCHs x 3 Idle Timeslots = 27

Total sub timeslots need for S4/4/4 = 4+24+87+27 = 142 sub timeslots

[aguntuk]

Site Configuration S4/4/4 need number of Abis Sub-timeslot allocation as below.
OML needs 1 timeslot (64kbps) = 4 sub timeslots (16kbps)
RSL for S4/4/4 = 6 timeslots (64kbps) = 24 sub timeslots (16kbps)
TCH for S4/4/4 = (12 TRXs x 8 TCHs) – (3 BCCHs) – (6 SDCCHs) = 87 sub


For MCS-9 needs 3 Idle Timeslot per 1 PDCH
Mostly cells have 3 PDCHs (1 PDTCH + 2 Dynamic PDCHs)
Total Idle Timeslot per site needed = 3 cells x 3 PDCHs x 3 Idle Timeslots = 27

Total sub timeslots need for S4/4/4 = 4+24+87+27 = 142 sub timeslots

Thanks a lot. But still I have some queries which are stated below. I hope you can also answer those queries also.


1. 1. You said for Site Configuration S4/4/4, RSL for S4/4/4 = 6 timeslots (64kbps) = 24 sub timeslots (16kbps). If my site configuration is changed like S6/5/8 or S4/5/5/3, will Abis TS be same?? What I mean how many RSL is needed for any site configuration and how much TS are needed per RSL? Is RSL is fixed for specific site configuration?

2.
2. For TCH for S4/4/4 = (12 TRXs x 8 TCHs) – (3 BCCHs) – (6 SDCCHs) = 87 sub TS, why BCCH & SDCCHs are subtracted during TS calculation?

3.
3. You said For MCS-9 needs 3 Idle Timeslot per 1 PDCH. If those Idle TS are 16kbps & Bitrate of MCS-9 is 61.85 kbit/s/slot. So for MCS-9, I need 4 16kbps Idle Timeslots [4*16 = 64]. Am I right?


I home you are not annoyed with too many queries. I just want to know those clearly. Thanks for understanding.

[RF engineer]

Thanks a lot. But still I have some queries which are stated below. I hope you can also answer those queries also.


1. 1. You said for Site Configuration S4/4/4, RSL for S4/4/4 = 6 timeslots (64kbps) = 24 sub timeslots (16kbps). If my site configuration is changed like S6/5/8 or S4/5/5/3, will Abis TS be same?? What I mean how many RSL is needed for any site configuration and how much TS are needed per RSL? Is RSL is fixed for specific site configuration?

2.
2. For TCH for S4/4/4 = (12 TRXs x 8 TCHs) – (3 BCCHs) – (6 SDCCHs) = 87 sub TS, why BCCH & SDCCHs are subtracted during TS calculation?

3.
3. You said For MCS-9 needs 3 Idle Timeslot per 1 PDCH. If those Idle TS are 16kbps & Bitrate of MCS-9 is 61.85 kbit/s/slot. So for MCS-9, I need 4 16kbps Idle Timeslots [4*16 = 64]. Am I right?


I home you are not annoyed with too many queries. I just want to know those clearly. Thanks for understanding.

1- For RSL is depend on your site TR setting called BTS Multiplex Mode. Which based on huawei is 2:1 which means 2 RSL for each TRX. for your configuraion of course is different you can calculated 6/5/8 = 19*8-(3BCCH)-(9SDCCH this example)=152-12=140 Idle TS is need.
2- RSL is taking care about both channel.
3-yes correct it required 4 idle ts.

[aguntuk]

1- For RSL is depend on your site TR setting called BTS Multiplex Mode. Which based on huawei is 2:1 which means 2 RSL for each TRX. for your configuraion of course is different you can calculated 6/5/8 = 19*8-(3BCCH)-(9SDCCH this example)=152-12=140 Idle TS is need.
2- RSL is taking care about both channel.
3-yes correct it required 4 idle ts.

Thanks. I understand 2 & 3, again to clarify more. I know 140 Idle TS is need for site configuration 6/5/8. My question was different. It was - How many Idle TS are needed for RSL for a site. As you said 2 RSL for each TRX on huawei, so for site config 6/5/8, I need 38 RSL???? is it correct??? Then how many Idle TS [16kbps] needed for those 38 RSL?? Calculation please.

Thanks you very much. your tutorial is very helpful for my understanding. Hopefully will get to know more from you in the future.

[RF engineer]

As worse case one RSL per TRX is enough, so add this TS to total.

BR

Aso

[aguntuk]

As worse case one RSL per TRX is enough, so add this TS to total.

BR

Aso

Then how many Abis TS [16kbps] is needed per RSL?

What I want to know, 1 RSL = ? Abis TS [16kbps]

Thanks.

[RF engineer]

Yes it is 16 kbps

BR

[aguntuk]

that means 1 TS (16k) is needed for 1 RSL, is that it?