Hi Bernard-
In anticipation of the purported upcoming WSJ piece on P-MP, the following:
I'm sure you noted the following comment from the recent WCII P-MP news item:
"..The network can provide multiple channels to each end-user building, and each channel will provide data rates of up to 250 megabits per second.."
( Message 5640725 )
Several questions - at a 2.5 b/Hz downstream channel efficiency, are we still in Pi/4-QPSK modulation ranges, or does this indicate a QAM variant? I know that 16QAM offers 3b/Hz, and 64QAM can squeeze 4.5 b/Hz. Or is compression how they suggest getting 2.5 with QPSK? (interesting to note that full non-lossy 30fps broadcast quality video is possible at 45Mbps - or 5 per (2.5b/Hz) channel)
And even though I dumped my $13.5 IPO TERN at issue Mon morning before it broke (and whew, boy did it), any value in or possibility of S-CDMA being applied to P-MP wireless, at least for upstream (since P-MP standards issue are not yet finalized)?
And is the SNR at 38GHz sufficient for higher order (64, 256) QAM?
And how many channels per building could they real world offer before their channel efficiency is offset by cochannel interference? And how much are higher order (16+) QAM schemes dependant on sectorization issues? And do you see P-MP radios which allow onsite optimization of these parameters, and perhaps even the capability of dynamic self re-optimize if/as conditions (noise, fade, etc.) change?
Lastly, any thoughts on NN's P-MP system?
And please feel free to correct any misunderstood assumptions apparent in these questions.
TIA
Steve |
