Problem of code congestion # 14.4Mbps

[josef]

Dear all,

We have a problem of code after activating 14.4Mbps on some sites. The problem apears only for 14.4 sites.

What can be the exact reason of this pb? How we can resolve it?

NB. vendor NSN

Thank you very much for your help.

[josef]

Guys,

Nobody have experience about this pb !!!

Br
Youssef

[josef]

Guys,

Here are the COCO parameters and IUB size for 14.4 Mbps:

Is it OK?

[Mctest]

Dear all,

We have a problem of code after activating 14.4Mbps on some sites. The problem apears only for 14.4 sites.

What can be the exact reason of this pb? How we can resolve it?

NB. vendor NSN

Thank you very much for your help.

For HS 14.4 Mbits 15 codes with SF16 are used.Do you use fixed code allocation for HS or dynamic?

[josef]

For HS 14.4 Mbits 15 codes with SF16 are used.Do you use fixed code allocation for HS or dynamic?

Dear bro,

we are using dynamic allocation on all the network. 15 codes feature is also activated.

waiting for your answer :)

[Mctest]

Dear bro,

we are using dynamic allocation on all the network. 15 codes feature is also activated.

waiting for your answer :)

Its strange!Because code congestion is connected with code tree usage.Check min max codes parameters per cell.Also check some kind priorities.

[josef]

Its strange!Because code congestion is connected with code tree usage.Check min max codes parameters per cell.Also check some kind priorities.

After activating 14.4 Mbps we hava a hudge increase of :

Nb of times SF8 unavailable (http://javascript<b></b>:void(0);)
Nb of times SF16 unavailable (http://javascript<b></b>:void(0);)
Nb of times SF32 unavailable (http://javascript<b></b>:void(0);)
Nb of times SF64 unavailable (http://javascript<b></b>:void(0);)
Nb of times SF128 unavailable (http://javascript<b></b>:void(0);)

but SF16 is most impacted
which parameters are related to this?

Thanks in advance

[josef]

where is our experts :confused:

It seems that we don't have anymore experts in finetopix :D

I'm waiting for your suggestions brothers.

Josef.

[gogotchiya83]

Dear Josef,
Thanks for your task,
Experts, can you explain what does it means congestion in 3G syst?
Plz Share some nice docs about this part of Live optimization?
Can you tell us what's the relationship between the SP and the troughput?
if we have HSDPA 14.4 what does it mean for the final user? can he reach this troughput during the downloads ....
What's about HSUPA?
...

[Mctest]

In case of dynamic allocation you should point min codes with SF16(e.g. 1 HS-PDSCH) and maximum (in your case 15).If R99 traffic increases you have more codes for R99 services and one guarantee code for HS.If no R99 traffic according to this feature more codes to the HS.As you said you have a lot of blocking.It means incorrect working of dynamic allocation or you guarantee a lot of codes for HS.

[josef]

In case of dynamic allocation you should point min codes with SF16(e.g. 1 HS-PDSCH) and maximum (in your case 15).If R99 traffic increases you have more codes for R99 services and one guarantee code for HS.If no R99 traffic according to this feature more codes to the HS.As you said you have a lot of blocking.It means incorrect working of dynamic allocation or you guarantee a lot of codes for HS.

you are right man.

We change HSPDSCHMarginSF128 from 0 to 8 and now we don't have congestion but. We don't have also 15 codes !!! but we have 14 codes for hsdpa. But I think that isn't normal. No?

Please can someone give me more explanation about HS-PDSCH code upgrade margin for SF 128 codes and MaxNbrOfHSSCCHCodes

Thank you in advance

Josef

[Mctest]

you are right man.

We change HSPDSCHMarginSF128 from 0 to 8 and now we don't have congestion but. We don't have also 15 codes !!! but we have 14 codes for hsdpa. But I think that isn't normal. No?

Please can someone give me more explanation about HS-PDSCH code upgrade margin for SF 128 codes and MaxNbrOfHSSCCHCodes

Thank you in advance

Josef

Do you have HSUPA?

MaxNbrOfHSSCCHCodes This parameter is responsible for code multiplexing of HSDPA users.If you want to schedule more than 1 user per TTI you should define more HS-SCCH channels.According to the spec max allowed - 4.

[gogotchiya83]

Dear Experts, I'm a beginner in 3G live optimization :(
can you explain what does it means congestion in 3G syst?
Plz Share some nice docs about this part of Live optimization?
Can you tell us what's the relationship between the SP and the troughput? what' about codes?
if we have HSDPA 14.4 what does it mean for the final user? can he reach this troughput during the downloads ....
What's about HSUPA?
...

[josef]

Do you have HSUPA?

MaxNbrOfHSSCCHCodes This parameter is responsible for code multiplexing of HSDPA users.If you want to schedule more than 1 user per TTI you should define more HS-SCCH channels.According to the spec max allowed - 4.

Thanks bro.

Yes we have hsupa. So?

[josef]

Dear Experts, I'm a beginner in 3G live optimization :(
can you explain what does it means congestion in 3G syst?
Plz Share some nice docs about this part of Live optimization?
Can you tell us what's the relationship between the SP and the troughput? what' about codes?
if we have HSDPA 14.4 what does it mean for the final user? can he reach this troughput during the downloads ....
What's about HSUPA?
...

gogotchiya83: if we have HSDPA 14.4 what does it mean for the final user?


For NSN RU10:

The maximum user bit rate allowed by the system for the HS-DSCH MAC-d flow depends on the active licences in the following way:
• If there is no licence for HSDPA 15 Codes feature, then the maximum user bit rate is 3.36 Mbit/s (corresponds to 3.6 Mbit/s air interface bit rate)
• If there is licence for HSDPA 15 Codes feature, then the maximum user bit rate is 6.72 Mbit/s (corresponds to 7.2 Mbit/s air interface bit rate)
• If there is licence for HSDPA 15 Codes feature with maximum number of codes 15 and HSDPA 10 Mbps per User feature, then the maximum user bit rate is 9.60 Mbit/s (corresponds to 10 Mbit/s air interface bit rate).
• If there is licence for HSDPA 15 Codes feature with maximum number of codes 15 and HSDPA 14 Mbps per User feature, then the maximum user bit rate is 13.44 Mbit/s (corresponds to 14 Mbit/s air interface bit rate).

[Mctest]

Thanks bro.

Yes we have hsupa. So?
And it is answer on your question:


We don't have also 15 codes !!! but we have 14 codes for hsdpa. But I think that isn't normal. No?

It's normal,because downlink HSUPA signalling channels(E-AGCH,E-RGCH,E-HICH) consume codes from code tree and maximum HS available codes are only 14.

[josef]

And it is answer on your question:

It's normal,because downlink HSUPA signalling channels(E-AGCH,E-RGCH,E-HICH) consume codes from code tree and maximum HS available codes are only 14.

It is not what we can see in our network (hsupa activated) !!!

When we put:
- MaxNbrofHSSCHCodes : Number of users multiplexed during TTI ==> 2
- HSPDSCHMarginSF128 : Number of free SF128 codes reserved ===> 0

We reach 15 codes but we increase code congestion

After we change to:
- MaxNbrofHSSCHCodes : Number of users multiplexed during TTI ==> 2
- HSPDSCHMarginSF128 : Number of free SF128 codes reserved ===> 7

We resolve the pb of code congestion but we cannot see anymore 15 codes

So???

[gogotchiya83]

Thanks Josef to your reply,
but what's does means "HSDPA 15 Codes feature", have you a doc about this part of live optimization?
Have you an analysis of the congestion of 3G syst?
The user reach the these Troughput if he is alone in the cell?
What about the number of CE dedicated for the cell?
PLZ help me in this task :L

[Mctest]

It is not what we can see in our network (hsupa activated) !!!

When we put:
- MaxNbrofHSSCHCodes : Number of users multiplexed during TTI ==> 2
- HSPDSCHMarginSF128 : Number of free SF128 codes reserved ===> 0

We reach 15 codes but we increase code congestion

After we change to:
- MaxNbrofHSSCHCodes : Number of users multiplexed during TTI ==> 2
- HSPDSCHMarginSF128 : Number of free SF128 codes reserved ===> 7

We resolve the pb of code congestion but we cannot see anymore 15 codes

So???


Could you give me description on HSPDSCHMarginSF128 parameter?

[josef]

Could you give me description on HSPDSCHMarginSF128 parameter?

The DL Channelization code tree is shared by the HSDPA traffic, DCH traffic and CCCHs. When HSDPA is activated in the cell it reserves a minimum reservation of 5 codes out of 16 SF16 codes. The code reservation for HSDPA and R99 traffic is controlled by following principles and monitored by the KPIs and counters.

The HSDPA code reservation is increased when the first HSDPA connection is setup to the cell or periodically while the HSDPA is active in the cell, if the cell is configured with higher number of codes than 5 (up to 15) and the UE support that also. HSDPA code reservation can be increased until the number of free SF16 codes is less that HSPDSCHMarginSF128 parameter. This parameter tells how much margin is reserved in the code tree.

This parameter could be set even to zero, because RT calls will pre-empt or downgrade HSDPA codes if SF16 codes are fully used.

HS-PDSCH code upgrade margin for SF 128 codes = Zero means you’ll allocate 15 codes for HSDPA only.

If the feature HSDPA 15codes is being used, we need to use a value less than the default value of 8.


Josef :)

[Mctest]

The DL Channelization code tree is shared by the HSDPA traffic, DCH traffic and CCCHs. When HSDPA is activated in the cell it reserves a minimum reservation of 5 codes out of 16 SF16 codes. The code reservation for HSDPA and R99 traffic is controlled by following principles and monitored by the KPIs and counters.

The HSDPA code reservation is increased when the first HSDPA connection is setup to the cell or periodically while the HSDPA is active in the cell, if the cell is configured with higher number of codes than 5 (up to 15) and the UE support that also. HSDPA code reservation can be increased until the number of free SF16 codes is less that HSPDSCHMarginSF128 parameter. This parameter tells how much margin is reserved in the code tree.

This parameter could be set even to zero, because RT calls will pre-empt or downgrade HSDPA codes if SF16 codes are fully used.

HS-PDSCH code upgrade margin for SF 128 codes = Zero means you’ll allocate 15 codes for HSDPA only.

If the feature HSDPA 15codes is being used, we need to use a value less than the default value of 8.


Josef :)

Hmm...but as I told it's strange(about blocking),because as mentioned in your description RT services pre-emt HS. But Max 14 codes for HS it is due to HSUPA and HS-SCCH code multiplexing.

[josef]

Hmm...but as I told it's strange(about blocking),because as mentioned in your description RT services pre-emt HS. But Max 14 codes for HS it is due to HSUPA and HS-SCCH code multiplexing.

In this case, how we got 15 codes??????????

Br
Josef

[Mctest]

In this case, how we got 15 codes??????????

Br
Josef

This is code tree limitation. If you look at the code tree you will see that hsupa and additional hs-scch channel consume codes from code tree and lower codes block usage of upper codes.

[dk2000]

This is code tree limitation. If you look at the code tree you will see that hsupa and additional hs-scch channel consume codes from code tree and lower codes block usage of upper codes.

Mr Mctest says true.

Because you had HSUPA and HS-SCCH = 2, it mean you can't reach the maximun 15 codes for HSDPA.

If you want to test, you can disable HSUPA and number of HS-SCCH channel = 1, you can reach 15 codes for 1 user

[josef]

Mr Mctest says true.

Because you had HSUPA and HS-SCCH = 2, it mean you can't reach the maximun 15 codes for HSDPA.

If you want to test, you can disable HSUPA and number of HS-SCCH channel = 1, you can reach 15 codes for 1 user

Guys,

I told you that we reach 15 codes with hsupa enabled + HS-SCCH = 3 + HSPDSCHMarginSF128 = 0

But when we change HSPDSCHMarginSF128 = 8 or 7 we reach maximum 14 codes but without code congestion (we didn't change the code set: 15, 14, 12, 10, 5)

So, base on this can someone explain me how we reach this 15 codes ????????

[josef]

Brothers,

After finalizing all tests to get 14.4 per nodeB in our network (1 sahred carrier + mainly 1shared BB scheduler), this is our conclusions:

In our network, we have mainly UEs category 7-8 which can support up to 10 codes. So, in order to use 15 codes we have to use code multiplexing feature by putting MaxNbrOfHSSCCHCodes (Maximum number of HS-SCCH codes) more than 1. We decide to put 2 as maximum number of HS-SCCH codes, because to multiplex 3 users on one TTI you need to share 15 codes between those users and this is possible only if we have mainly UEs category 1-6 (with full buffers) in our network.

Decided value for MaxNbrOfHSSCCHCodes is 2

Impossible to get 15 codes (main prerequisite to get 14.4 Mbps per nodeB) without putting HSPDSCHMarginSF128 = 0 : NO codes left for Rel 99 è Code congestion

With this limitation we can go up to 14 codes only. So, now we need to know how many codes (SF128) can we keep for DPCH channels (RT & NRT)?

According to our test, we lost the 14th code after HSPDSCHMarginSF128 = 8

Decided value for HSPDSCHMarginSF128 is 8

Conclusion:

1. We cannot have 14.4 Mbps per nodeB with one shared carrier: We need HSDPA dedicated carrier in order to have 15 codes è 14.4 Mbps per nodeB

2. For actual situation, this is the best parameter set:
ü MaxNbrOfHSSCCHCodes = 2
ü HSPDSCHMarginSF128 = 8
3. NSN must provide explanations about their recommendations to reach 15 Codes (14.4 Mbps per nodeB) è “HSPDSCHMarginSF128 less than 8” !!!

I'm waiting for your expertise guys :)

Your comments & suggestions are welcome.

Josef.

[josef]

Brothers,

After finalizing all tests to get 14.4 per nodeB in our network (1 sahred carrier + mainly 1shared BB scheduler), this is our conclusions:

In our network, we have mainly UEs category 7-8 which can support up to 10 codes. So, in order to use 15 codes we have to use code multiplexing feature by putting MaxNbrOfHSSCCHCodes (Maximum number of HS-SCCH codes) more than 1. We decide to put 2 as maximum number of HS-SCCH codes, because to multiplex 3 users on one TTI you need to share 15 codes between those users and this is possible only if we have mainly UEs category 1-6 (with full buffers) in our network.

Decided value for MaxNbrOfHSSCCHCodes is 2

Impossible to get 15 codes (main prerequisite to get 14.4 Mbps per nodeB) without putting HSPDSCHMarginSF128 = 0 : NO codes left for Rel 99 è Code congestion

With this limitation we can go up to 14 codes only. So, now we need to know how many codes (SF128) can we keep for DPCH channels (RT & NRT)?

According to our test, we lost the 14th code after HSPDSCHMarginSF128 = 8

Decided value for HSPDSCHMarginSF128 is 8

Conclusion:

1. We cannot have 14.4 Mbps per nodeBwith one shared carrier: We need HSDPA dedicated carrier in order to have 15 codes è 14.4 Mbps per nodeB

2. For actual situation, this is the best parameter set:
ü MaxNbrOfHSSCCHCodes = 2
ü HSPDSCHMarginSF128 = 8
3. NSN must provide explanations about their recommendations to reach 15 Codes (14.4 Mbps per nodeB) è “HSPDSCHMarginSF128 less than 8” !!!

I'm waiting for your expertise guys :)

Your comments & suggestions are welcome.

Josef.

What do you think experts?

[maasricht]

Code Congestion started in our network.

HSUPA enabled, and made drive test with all variations, but never reached 15 codes (because of HSUPA Enabled).

MaxNbrofHSSCCH Codes =3
HSPDSCHMarginSF128 =8, to 2 and 0.

If it's 8 - we saw 12 codes. when we changed to 2 or 0. 14 Codes we got it.

The other hand, after this feature, code blocking started. How to solve it?

[josef]

Code Congestion started in our network.

HSUPA enabled, and made drive test with all variations, but never reached 15 codes (because of HSUPA Enabled).

MaxNbrofHSSCCH Codes =3
HSPDSCHMarginSF128 =8, to 2 and 0.

If it's 8 - we saw 12 codes. when we changed to 2 or 0. 14 Codes we got it.

The other hand, after this feature, code blocking started. How to solve it?


You can play with CodeTreeUsage (default value 40%), in order to redistribute codes early ;) (try 30%, 25%, 20%)

You can also play with:
DPCHOverHSPDSCHThreshold (NRT DPCH over HS-PDSCH code offset) from 5 (default value RU10) to 0 (default value RAS06)
This parameter defines the number of allocated HS-PDSCH codes that are not allowed to pre-empt by NRT DPCH in the case NRT DPCH code congestion. The value of the parameter is an offset from the maximum allowed number of HS-PDSCH codes.

Br
Josef