https://en.wikipedia.org/wiki/Rake_receiver
From: AF <[email protected]> On Behalf Of Adam Moffett Sent: Thursday, July 10, 2025 1:53 PM To: 'AnimalFarm Microwave Users Group' <[email protected]> Subject: Re: [AFMUG] RAKE vs OFDM for multipath RAKE is a new term for me. I don't know anything about it. My experience with OFDM is that how well it works scales with power consumption of the device, which in turn is dependent on its signal processing capability. An 802.11 device does whatever the commodity silicon does. An LTE base station needing hundreds of watts of power can produce data out of almost nothing. WiMax produced middling outcomes, and those base stations needed 30W-100W depending on vendor. This is speculative, obviously, but it's based on what I saw with my own eyeballs. I'd love to see something showing us SNR before and after signal processing. If we did, I think the outcomes would track with power consumption like I'm saying. _____ From: AF <[email protected] <mailto:[email protected]> > on behalf of Ken Hohhof <[email protected] <mailto:[email protected]> > Sent: Thursday, July 10, 2025 2:15 PM To: 'AnimalFarm Microwave Users Group' <[email protected] <mailto:[email protected]> > Subject: [AFMUG] RAKE vs OFDM for multipath Any RF communication nerds here? I have read that both OFDM and RAKE deal with multipath but are not usually used together. How true is this? The company that begins with T implies they implement a RAKE receiver but I haven't heard them explicitly use that term. Do they actually have multiple receivers for each "finger" of the rake, at both base and remote node? Myself, I don't totally buy that OFDM deals with multipath in the way claimed. Yes, the cyclic prefix is a trick to make a continuous signal look cyclical so that DFT can do the work of FFT, and yes the cyclic prefix needs to be long enough so that delayed multipath reflections don't invalidate that. But it doesn't seem to process each reflection separately and then add them back together. Maybe as an armchair RF engineer I just don't understand how it works, that's entirely possible. I also can't wrap my brain around how a RAKE receiver would separately process multipath versions of the signal if they are identical but exactly 180 degrees out of phase. If they cancel, they cancel, I don't see how you avoid a fade in that situation. But again, maybe I just don't understand. But tl;dr does the T company use both OFDM and RAKE at BN and RN, despite conventional wisdom that you don't use both, and that RAKE is mostly used with DSSS?
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