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#1 2008-Jul-31 10:22:56

moodo
Member
Registered: 2008-Jul-18
Posts: 26

switching diversity

I just have a short theoretical question, I haven't found an answer on it yet: What does switching diversity?

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#2 2008-Jul-31 10:43:35

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: switching diversity

It's when a receiver chooses among multiple receive antennas, based on some metric of channel quality. In our reference design, the SISO OFDM receiver can select from 2 receive antennas per-packet, based on the received SNR (using AGC gain choices as a proxy for direct SNR measurement). This scheme achieves spatial diversity, allowing the link to function even if one antenna is in a deep fade.

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#3 2008-Jul-31 10:55:58

Amir
Member
Registered: 2007-Jun-18
Posts: 92

Re: switching diversity

What happens to the AGC gain if I remove one of the radio cards? With switching diversity enabled, it seems like the radio slot without the radio card is being selected whenever a packet is detected.

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#4 2008-Jul-31 10:57:57

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: switching diversity

I'm not sure what happens in the absence of a radio board. The RSSI and ADC data pins have pulldown constraints applied, so they should report zero energy to the AGC core. But to be safe, you should disable the second radio and switching diversity in software.

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#5 2008-Jul-31 11:07:23

moodo
Member
Registered: 2008-Jul-18
Posts: 26

Re: switching diversity

Thank you very much for the answer!

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