WCDMA downlink in FDD mode - which bit pattern

WCDMA

HI!

I am developing WCDMA downlink in FDD mode.

Let me know, is it compulsory to transmit Common Pilot Channel (CPICH) if i have primary and secondary synchronization channel working properly?

If yes can anyone know which bit pattern i should use? Can i use any random bit pattern?

WCDMA

Yes. It is, the basic scrambling code is presented to the MS via the common pilot channel. But since it is a simulation you can skip it. Read 3gpp standard TS.25.213 v3.6.0

Hope that helps

Re: WCDMA

Do you mean that CPICH is used to provide information that which scrambling code number that MS should use to descramble?

If i transmit all pilot bit "1", is it okay? because I want to complete the whole downlink.

And suppose if i skip this CPICH, will it affect on receiver side design? I have not design receiver yet.

WCDMA

Sure you can either transmit a 1 or 0, because at the end you would have to map these logical values to physical values of +/-1 (map any way you like)

Now you may be able to skip Pilot channel since in the simulation you'll give your MS the scrambling code. I dont think you would built a receiver that will try to find the scrambling code itself (your model will be very complex, try this only when you have a lot of time)

By the way a guy at our yahoo group wants to work on WCDMA simulation, if you're interested then either join the group 'telecom_research' or I give you his email address in a private message so that you can contact him. I'm kinda busy these days and cant afford to start explaining from the beginning.

Also if you are good at Simulink, we should start a thread for help in Simulink. What do you say? Sometimes even I am having incorrect results.

Re: WCDMA

Thanks for the reply.....

i will work on your advise. kindly provide the e-mail id of the person that you are talking about. I will contact him.

Actually i started my work with simulink only, but what i suppose that simulink is not good tool as signal property changes sometime when going from one block to another block and have some time problem of matching sampling frequency. Thats why i prefer matlab coding more then simulink although simulink is good for real-time operation..

I am not very much expertise in simulink, but we can start a thread related to matlab coding.

WCDMA

Something is wrong with my yahoo, I cant sign in, so I have sent a message for you to a member Zafi shah, he will invite you & also give you the person's email id. He'll forward you my message