How the network decide if use hsdpa or r99?

[Weiland86]

Hello guys,


Recently i had an interview and could not answer the next question...

When and how and based on what the network decide use hsdpa
when and how and based on whatdecide to use r99 channels?
what are the requirements or the process to decide this? considering different data rates required.


Thanks in Advance.


BR,
Weiland

[Aidoooo]

Depends on the phone and the network, the 1st 3G phones all had a data connection of 384kbits and some networks use a different apn for r99. Also the advantage of sharing single carrier between HSDPA and R99 is the resource efficiency.Since HSDPA uses the transmission power of Node-B which is remained after the power assignment to R99 calls. Therefore, if the traffic of R99 call is low, the remaining power available for HSDPA will be high and high HSDPA performance will be expected. Another advantage is that sharing the single carrier could save the operator’s investment and running cost of Node-B. The disadvantage of this configuration is an impact on the performance of end-user experience. If the traffic volume of R99 call becomes high, the remaining power available for HSDPA will be reduced and as a result HSDPA performance received at end-user will also become low. In addition, HSDPA can become interferer to R99 call since HSDPA can use all the remaining transmission power. Such a high power transmission would increase the interference on R99 call and it would lead to the shrink of R99 service area.

[vivero]

Hi guys!

I think all of them base on QoS you set on the network. You can set one service has higher priority than another.
But in fact, we usually set Voice higher priority than R99 and higher than HSDPA...
You need features which can support the services or data rate you want.

Regards!

[Weiland86]

hi guys,

@Aidoooo: I know how hsdpa and r99 works, however i think you did not answer the question you only explain what you guess (that is what i did in the interview).

I think the next question can clarify something
If we have 2 carriers one for r99 and 1 for HSDPA based on what the network send you to 2nd carrier? how the network knows that what you are requesting belongs to hsdpa and not to r99, I guess if the data rate does not match with Radio bearers from r99 it will be send to hsdpa but i am not sure...

BR,
Weiland

[Nyquist]

Hi friends.
Something simpler that complements your answers.
When a UE requests a data service it informs to the network (Core) which capabilities it has, i.e, HSDPA up to 7Mbsp, only R99,..., then the network checks the subscription (max throughput available for the user). Then the network negotiates with RAN the best bearer to provide the data services requested by the UE. Then the network will provide mobility and data switching (HSDPA - R99) according to its configuration (max number of HSDPA users per cell, HSDPA coverage,...).
For instance, if a UE is HSDPA 14Mbps capable and it has a subscription for only 7 Mbps (or the network cannot provide higher bitrates), the network checks if there is resouces for admiting it in HSDPA. If so, will provide a HSDPA RAB limited to 7Mbps. If there is not HSDPA free resources the network will provide a R99 RAB instead.
Please, note that HSDPA is more efficient than R99, so the network should be configured to prioritize HSDPA data services.

I hope it could help.
Regards

[Weiland86]

Hi Nyquist,

Yes what you said it is true but i think is also depends on the data rates althougth hsdpa is more efficient than r99 i am pretty sure there some data rates (RAB) that always are going to be send to R99, because if we always want to use HSDPA so why we still use R99??

So I think there is also a treshold or trigger that let you start to consider use HSDPA instead R99...

Unfortunately as i know this is not like a general information that we can consult in a book... If omseone else have a different idea or even better know exactly how this works please don't hesitate to get involved...

BR,
Weiland

[Nyquist]

Hi Weiland86.
I would say that R99 Data and HSDPA will coexist for long time. HSDPA is optional and there are UE's that dont support HSDPA and even networks with only R99.
As I said, HSDPA is more efficient, so the operator's strategy should be based on keeping all the HSDPA capable UE's in HSDPA RAB or FACH before going to Idle.
Operators are able to configure all these things to avoid that HSDPA users use R99 Data.

I hope it helps.
Regards

[wolverine]

If the UE supports HSDPA and the cell is HSDPA capable, the RNC will assign HSDPA
If the UE does not support HSDPA or the cell does not support HSDPA or the max number of HSDPA users has been reached, the RNC will assign R99

[rfsupp]

Dears,

Just remember too that we define at the RNC a threshold to use DCH or HS-DSCH. So if you receive an RAB Assigment Request with MBR=1Mbps and your threshold from DCH to HS-DSCH is 4Mbps, the UE never will change to HSPA service.

Other thing is since 2007 I never saw a network based on full/major R99 users (and a few phones are just R99). The HSPA service is much more efficient in many aspects, that I could spend 500 hundred lines describing it.
But we still use R99, because CS is a R99 service or in same cases that the license of HSPA is not enough (poor operators).