Hi Greg
I did mention that I was only considering computing the PAPR, and then
if it exceeded some threshold, produce a new sequence... On the
likelihood you wont get another bad one. IE a gamble.
I'm interested that you are considering what can be done at the receiver
end to improve performance.
g
On 6/22/2020 3:05 PM, Greg Maxwell wrote:
On Mon, Jun 22, 2020 at 4:55 AM glen english <[email protected]> wrote:
One thing to consider- accurate PAPR measurement (by a receiver) is
hard at low SNR.
That is one of the nice things about FEC based PAPR reduction, the
receiver doesn't need to measure PAPR yet it exploits the PAPR
reduction regardless.
Think of it this way: The sender adds redundancy to improve PAPR but
if the redundancy is FEC efficient then it is free in a BER vs SNR
sense. And this holds even if the transmitter wasn't PAPR limited.
Tone reservation is probably the lowest cost means for this setup. And
backward compatible.
Absolutely there. Though I don't see a way for the receiver to exploit
the pilot tone. So it's only a win to the extent that it lets you
increase the output amplitude.
Remapping as I described this morning is probabaly reasonable, also-
--given that LDPC encode is approximately a LUT and the FFT (DFT?) is
very short.
Codec2 frames I think are a little too long for an entirely brute
force approach to work.
(By brute force, I mean, consider all possible OFDM words, select the
2^(code2_bits) codewords with the lowest PAPR, an map them to the
codec 2 frames... then use a maximum likelyhood decoder).
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