802.11 Sync on MRC receiver

Started by cogwsn 6 years ago3 replieslatest reply 6 years ago110 views


Is this correct that when we implement MRC in 802.11a/g (say with 2 antennas), the preamble based sync needs to be performed on both the antennas ? 

If yes, then are there chances that one antenna can achieve sync while the other couldn't ?

What would you suggest ? 



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Reply by SlartibartfastMay 8, 2018

Yes, you need synchronization so that the two channels can be added coherently, rather than potentially cancelling or distorting each other worse than just single-channel reception.  The most accurate SNR estimation will also be possible with a synchronized signal.

If synchronization is not achieved, then don't combine from that antenna.   This allows the system to degrade to just switched diversity if one channel isn't available.

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Reply by cogwsnMay 8, 2018

Hi, I have a followup question. Using STS we perform coarse frequency offset estimation and then using LTS , we refine the frequency offset estimation. When performing MRC, can I use the average of frequency offset estimation of individual branches ?

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Reply by SlartibartfastMay 8, 2018

Since each receiver has to attain its own synchronization independently, each receiver must estimate and use its own frequency offset information.

There may be opportunities to simplify this if both receivers use the same frequency reference.