HS codes

[apurvabelekar]

Hi Experts,
I am working on Huawei RAN14 where the HS-PDSCH codes min is set to 5 and max is set to 15. Still in a drive my UE is 60% times is getting only one code. Does anyone know why is this happening? IS there anyother parameter governing the HS codes allocation?:(

Thanks in Advance.

[babak1349]

Hello,
Please note that the code allocation depends on different things:
1) Number of R'99 users and traffic in the cell. Voice and RRC have higher priority than HSDPA. So if there is no code available for HSDPA you cna not have too many codes. So check the code utilization for R'99 from stats.
2) The UE category and check how many code it can supprt
3)The scheduler allocates the codes based on available data in buffer for specific user So you cna have problem with Iub and the data can not be transfered to the users and the scheduler allocate less codes. In this case you need to check the Iub utilization and Iub configuration.
4) HSUPA also can cause low throughput. It means when you are uploading a file, you have code allocation in DL HSDPA but just a few So when you are uploading a file in the same time your DL throughput can decrease due to less traffic and it can affect your overall DL throughput So you need to separate UL and DL data transfer (similar case is applied for HSDPA/DCH) whne you are nalayzing the result
5) Scheduling algorithm is also important for example when it has been set to the best C/I, the users in poor radio conditions may suffer



So here is further suggestion:
1) do the stationary drive test near to the site with good radio condition and with only one Serving cell ( good RSCP, good EcNo) It is better to do it at night or in low traffic period of time
2) Check HSDSCH DTX in your drive test tool when you are downloading a file , if it is very high during downloading a file it means you have TN problem
3) disable HSUPA and run the same test


Hope it can help you

Cheers


Hi Experts,
I am working on Huawei RAN14 where the HS-PDSCH codes min is set to 5 and max is set to 15. Still in a drive my UE is 60% times is getting only one code. Does anyone know why is this happening? IS there anyother parameter governing the HS codes allocation?:(

Thanks in Advance.

[P.T.E.]

Maybe, dynamic code allocation is set on NodeB level, so whatever the config on RNC it will be useless, since the deciesion is made by NodeB.

BR,


Hi Experts,
I am working on Huawei RAN14 where the HS-PDSCH codes min is set to 5 and max is set to 15. Still in a drive my UE is 60% times is getting only one code. Does anyone know why is this happening? IS there anyother parameter governing the HS codes allocation?:(

Thanks in Advance.

[babak1349]

Hello P.T.E,
good point . In Dynamic code allocation in E******* as far as (it allows to allocate baseband Resources to HSDPA users per cell dynamically it means it can share among different cells) To have dynamic code allocation in Air interface in E******* "flexible scheduler" feature should be activate and I think it now is a basic feature.
Anyway he/she should check the Baseband resource allocation for HSDPA as well in nodeB as you have mentioned

Cheers

Maybe, dynamic code allocation is set on NodeB level, so whatever the config on RNC it will be useless, since the deciesion is made by NodeB.

BR,

[P.T.E.]

As far as I know for huawei, code allocation decision could be on NodeB level, or on RNC level, but for sure it will be more efficient on NodeB level.

[ltecity]

You can check resource utilization from OSS reports.
It HS code utilization shows blank value or less value for 10 to 15 th code than you have some configuration problem.
If it shows good value than you can check radio condition ans users etc.

[rnpopt]

I am agreed with P.T.E. I guess dynamic code allocation is set to node B level. So ' min is set to 5' is valueless in that case. And in that case 'Code number for HS-PDSCH' (HSPDSCHCODENUM) is used as the minimum code for HSDPA. And I guess it is set to '1' in this case. Please check these parameters.