Shannon's upper bound for AWGN channel, but what about Multipath?
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From: steveu on 12 Apr 2010 12:47 >On Apr 8, 4:55=A0am, "Marco.Pausini" ><marco.pausini(a)n_o_s_p_a_m.gmail.com> wrote: >> Actually the answer is a bit more complicated. >> >> The capacity of a time-invariant multipath channel is not given by a sing= >le >> formula, but it depends on what the transmitter and receiver know about t= >he >> channel. Also, the definition of channel capacity for fading channels is >> not unique. Finally, capacity of a time-varying multipath channel is >> unknown in general, although it can be approximated. >> >> For an introduction to this topic, refer to "Wireless Communications", A. >> Goldsmith, Chapter 4. >> >> Marco > >thanks to all for the comments... > >It seems if the receiver can sort out the mess, the more rays you get >the more signal power you get so in theory the channel capacity should >improve... of course in practice, it's a mess.. > >Mark If the paths are very stable you could have sustained nulling from multiple paths, resulting in almost no received signal at all. It all depends how they add up. Steve |