Re: [Discuss-gnuradio] Designing a good receiver

[Patrick Yeon]

On 06/02/2011 07:10 AM, Mike Clark wrote:
> Anyways, the question I have is, is there a general procedure one can
> follow to design a decent receiver in gnuradio? For example, I have a
> project that I'm using for experimentation where my receiver looks
> like this: USRP Source ->  GMSK Demod ->  Packet Decoder ->  File Sink.
> This works well when I have the USRPs cabled together and even when I
> have antennas with line of sight (I haven't checked max distance).
> When I don't have line of sight, however, I stop receiving packets.
> Are there any other gnuradio blocks I can add in to my setup which
> will help get better performance when there is no line of sight?

The first step I would take in your situation is to find the case where 
you just barely stop receiving packets (you say it's based on line of 
sight, and are you sure that it's that, and not distance or path 
attenuation?), eg. just around a corner in your office/home. Then I'd do 
a direct USRP Source -> File Sink capture, and "play with" the captured 
data offline, running it through signal graphs to check power, 
multi-path, or whatever else may be causing problems. This analysis 
would suggest what kind of additional processing you may need to be able 
to get the link working on-line.

-Pat