[walei]

Hi all, I'm working for a company that is looking to make 3G ODM phones...so we've all been doing some studying.. I have come across a question that is somewhat technical...not sure where I can get help? If anyone can help me it's greatly appreciated, or redirect me to a site where I may be able to get some answers?

Anyways here is the question.

In UTRAN phsyical layer, radio measurement (interfrequency) is done during compress mode to examine interference. For the UTRAN uplink, it needs to be in compress mode...what about downlink, is there any interfrequency measurement needed?

On the UE side, downlink compressed mode is not needed if the UE has dual receivers, but uplink does. Why?

And for both UTRAN and UE, when exactly is compressed mode to measure interfrequency interference needed?

I LOVE YOU if you can answer my Qs or know where I can get help :cool:

[Ben]

I have no knowledge at that level I'm afraid, but you might want to try the following googles:
http://www.google.co.uk/search?hl=en&q=UTRAN+physical+layer+measurement+compress&spell=1
http://www.google.co.uk/search?hl=en&q=UTRAN+physical+layer+UE&meta=

Some more technically-minded members may also be able to offer their own suggestions.

Welcome to Talk3G :)

[3g-g]

Hi all, I'm working for a company that is looking to make 3G ODM phones...so we've all been doing some studying.. I have come across a question that is somewhat technical...not sure where I can get help? If anyone can help me it's greatly appreciated, or redirect me to a site where I may be able to get some answers?

Anyways here is the question.

In UTRAN phsyical layer, radio measurement (interfrequency) is done during compress mode to examine interference. For the UTRAN uplink, it needs to be in compress mode...what about downlink, is there any interfrequency measurement needed?

On the UE side, downlink compressed mode is not needed if the UE has dual receivers, but uplink does. Why?

And for both UTRAN and UE, when exactly is compressed mode to measure interfrequency interference needed?

I LOVE YOU if you can answer my Qs or know where I can get help :cool:


I'm not 100% sure at the moment... but if I get the time I can try and find out some more. From reading what you've written here's my understanding, I may be taking it completely the wrong way, so feel free to tell me if it's sounding completely wrong!

By dual receivers do you mean both UMTS and GSM frequencies or both main and diverse RF paths? I've kind of tried to use both to explain...

I'd imagine that UTRAN uplink is compressed, partly and not always (?), due to the power limitations of the handset, the smaller the information it has to transmit the longer the battery life, whereas on the DL the WBTS has the luxury of a higher output. The handset will be measuring power and signal to noise ratio for HO/quality issues etc as well as the controlling RNC, but not to the extent of the controlling BTS. However I'm no handset manufacturer so don't take it as gospel.

Again your next question is handset based, I'm really not sure of the makeup of a handset receivers... on the network side I believe all the UMTS operators use a main and diverse receive path at their AE, thus giving a greater chance of success for the RF path back to the WBTS, could this greater chance of signal reception and gain if applied to a handset allow the need for compression not to be applied?

Lastly, I believe compressed mode to measure interfrequency interference is needed for the handset to perform UMTS -> GSM handovers. When moving from the UMTS network to the GSM the handset has no view of the network it's about to hand into, it has to perform measurement tasks in order to keep the call active, by compressing the frame of current information the handset can perform a quick measurement in order to plan with the controlling RNC & MSC the handover relevant to it's recieved signal to noise ratio.

I hope it's of some use :p

If it helps then let us know.

G.

[walei]

From my understanding, compress mode means the following. Since WCDMA transmission in FDD is in one frequency only, there is no way for the link to go to another frequency to measure the intereference with only one receiver. Therefore the transmission is paused in intervals (at specified timeslots) and during these intervals another transmission is created to measure the interfrequency intereference.

I found out that uplink compressed mode must be used if the frequency to be measured is close to the TDD frequencies or GSM 1800/1900...and compressed mode is only used for UE without dual receivers in the DOWNLINK, and uplink must use compress mode no matter what...

You're right G, compress mode is mainly used to measure which channel is the most suitable for a handover, to another cell or to GSM network.

So my question still remains, since DL in UE does not need to use compress mode as long as it has dual receivers, what MUST uplink for UE use compress mode? My current guess is by dual reciever they mean UMTS/GSM, and at the network side it's either UMTS or GSM, never can have both, so for UL compress mode must be used...? I'll let you know if I found out more!

Thanks for all the help you guys :):):):)

[bsrjl1]

For the uplink, it depends on the Tx/Rx frequency spacing. If it's fixed, you must use compressed mode. Variable it's not necessary.