View Full Version : HSDPA questions
fon909
2011-11-21, 03:33 PM
Hi,
Can anyone please answer the questions;
If downlink power is increased from 20W to 40W, will the HSDPA throughput increase?
How many users can be handled by scheduler in fast channel scheduling ?
How much power is required by common and dedicated channels?
Thanks.
plannerguy
2011-11-21, 06:32 PM
Hi
some thing which i found in my network
40W DL Power upgrades are helpful in increasing the capacity,in coverage improvemnt after increasing CPICH power from 33dBm to 36dBm.
upgrade toatl Tx power and HSDPA related powers only,power settings for NRT-DCH (R’99 PS) should be kept untouched. This would help us to enhance the capacity for RT and HSDPA services.
Regards
Plannegruy
jan74
2011-11-21, 09:04 PM
Hi,
Can anyone please answer the questions;
If downlink power is increased from 20W to 40W, will the HSDPA throughput increase?
How many users can be handled by scheduler in fast channel scheduling ?
How much power is required by common and dedicated channels?
Thanks.
The quick answer is yes. You will get good improvements there. We got a 10% Average Throughput per user increase when we increased the Tx power available to the UE for HSDPA by 3dB.(as it happens, it was less than 3dB). By increasing your cell size from 33dBm to 36dBm, you will waste some of the extra power by increasing the cell size. Sounds to me like you want better throughput and more power for HS, with no increase in cell size will help.
As for HS Users, it depends what vendor but NSN allow up to 72 Simultaneous HSPA users per Scheduler.
Hi,
Can anyone please answer the questions;
If downlink power is increased from 20W to 40W, will the HSDPA throughput increase?
How many users can be handled by scheduler in fast channel scheduling ?
How much power is required by common and dedicated channels?
Thanks.
my opinion is that there will not be any improvement in User Throughput if you increase power from 20W to 40W. Total power increase will not improve CQI so there is no question of throughput improvement. In case, there is Power Congestion in cell then there will be improvement in Access Success Rates by increasing total power. Power Margin and Hspa Power can be changed to allocate more power for HSDPA that can help to add more users for scheduling.
No. of users are controlled by parameters in cell and nodeB. it is not limited by Scheduler anyway.
5-10% of power is used for CPICH and other common channels takes 10-15 % depending on CPICH. 75-80% is left for other dedicated services.
jan74
2011-11-22, 05:37 PM
my opinion is that there will not be any improvement in User Throughput if you increase power from 20W to 40W. Total power increase will not improve CQI so there is no question of throughput improvement. In case, there is Power Congestion in cell then there will be improvement in Access Success Rates by increasing total power. Power Margin and Hspa Power can be changed to allocate more power for HSDPA that can help to add more users for scheduling.
No. of users are controlled by parameters in cell and nodeB. it is not limited by Scheduler anyway.
5-10% of power is used for CPICH and other common channels takes 10-15 % depending on CPICH. 75-80% is left for other dedicated services.
I can assure you that increasing the available power for HS does work. We tried it and it worked very well. We got 10% throughput per user increase across the board and we also saw improvements in CQI. The amazing thing was that there were no negatives.
paboya
2011-11-22, 05:39 PM
For adjusting Power...
recomended per cluster not per Node-B
I can assure you that increasing the available power for HS does work. We tried it and it worked very well. We got 10% throughput per user increase across the board and we also saw improvements in CQI. The amazing thing was that there were no negatives.
You must have increased CPICH also. Improvements were due to CPICH increase, total power increment does not help in any improvement in throughput.
jan74
2011-11-23, 01:32 AM
No. We did not increase CPICH. We increased the amount of power available for HSDPA. This means more power per user = more throughput.
agenov
2011-11-23, 02:48 AM
how works NodeB Mac-hs schedulere is entirely vendor specific and usually forbidden info but what you need to know is that reported CQI by UE is compensated in the NodeB since it only knows how much power is available unlike UE that does it based on an assumption. What i've seen so far is NodeB checks available resources in the meaning of available power, H codes, even BER and etc. and does scheduling so for sure more power resource at the cell better throughput (especially for higher rates) achieve. Since HSDPA power allocation is dynamical that uses remaining power it is possible to suspress CPICH so usually is recommended CPICH power to be 10% from the total power.all other common channels are relevant to CPICH power and usually is around 20%-25%.
No. We did not increase CPICH. We increased the amount of power available for HSDPA. This means more power per user = more throughput.
This information sounds strange to me, but I will try to find the reason for same...Thanks anyways
dodotiro
2011-11-23, 01:40 PM
Hi,
Can anyone please answer the questions;
If downlink power is increased from 20W to 40W, will the HSDPA throughput increase?
How many users can be handled by scheduler in fast channel scheduling ?
How much power is required by common and dedicated channels?
Thanks.
1.IMHO ya, HSDPA throughput depends on environment. if your power upgrade able to accommodate that thing, i am sure it will increase the troughput.
2.For coverage , yes it will increase the coverage.
3.For HSDPA user, it depends on license you have bought. for huawei max concurrent user is 64. can be upgrade up to 96. but for potential user will increase as the coverage also increase -->> can drive to congestion
jan74
2011-11-23, 05:40 PM
This information sounds strange to me, but I will try to find the reason for same...Thanks anyways
I can assure you its true, I made the change myself! First we did a full RNC and then we did a 2nd RNC and finally the network. We increased the amount of available HSDSPA power from 40dBm to 41.8dBm. CPICH did not change at all. And even though I looked and looked, I could not find any negatives. There was a step change in Throughput per user, by around 10%. The vendor was NSN.
melkaiy
2011-11-25, 10:01 PM
jayk is right increasing the cpich power is not increasing the throughput. You just extend the coverage therefore more users can be covered but for instance that congestion is concern there will be a phenomenon called cell breathing in which too much users will increase their ms tx powers thus resulting in cell shrinkage. Power doesn't have to be involved with throughput because throughput in 3g depends on channelization codes/spreading factor. If you want to increase the throughput must you decrease the the channelization factor or the spreading factor.
please add reps if you like this. thnkx
agenov
2011-11-25, 11:19 PM
Throughput is related with reported CQI that is considered by the NodeB scheduler further. How UE estimates CQI is not specified and is vendor specific but is based on radio condition levels. If you can improve the levels you will have higher CQI so and throughput.By increasing CPICH is one way to achieve it! DL Power like other resources is shared among users so more power available higher throughput.
BR
jayk is right increasing the cpich power is not increasing the throughput. You just extend the coverage therefore more users can be covered but for instance that congestion is concern there will be a phenomenon called cell breathing in which too much users will increase their ms tx powers thus resulting in cell shrinkage. Power doesn't have to be involved with throughput because throughput in 3g depends on channelization codes/spreading factor. If you want to increase the throughput must you decrease the the channelization factor or the spreading factor.
please add reps if you like this. thnkx
it will improve CQI a little...because of the power sharing but not so much... in my opinion is little noticeable.
CQI calculation will use also CPICH. so yes, I expect a little improvement on user´s throughput
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