Subject: Re: [manet] Is it difficult to receive simultaneously over multiple channels?

From: [email-masked]
Date: Thu, 7 Oct 2004 10:38:01 -0500

Is it possible to receive simultaneously over multiple channels?
- Obviously yes when you think about cellular base stations that are
receiving multiple channels simultaneously.

By-the-way, I believe that the first digital network that received
simultaneously over multiple channels, where all nodes were mobile (as
compared to cellular systems where the base stations are stationary), was
an experimental system demonstrated at sea for the Navy in 1958 or 1959
using a variant of the Collins Radio Kineplex data communications system (
http://www.collinsradio.org/Collins_1959_Kineplex.pdf).  I believe that
this experimental system was also the first to use automatic power control
to mitigate against near/far problems when receiving multiple channels
simultaneously  (http://www.stormingmedia.us/89/8987/A898791.html).  Also
interesting to note is that Kineplex modulation appears to also be the
first multi-carrier modulation (i.e. OFDM modulation) and was used to
improve performance against multipath (
http://www.engr.colostate.edu/ece/pages/Research/rawcom/paper63.pdf).

Is it difficult to receive simultaneously over multiple channels?
- Yes, but it is getting easier every year, especially with modern software
defined radio (SDR) technology.  Of course even through the hardware and
computing costs are dropping, you still have to worry about physical and
data link layer issues like near/far problems, transmit/receive
coordination (depending upon half/full dux capabilities), etc.

Jim Stevens

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