On Multipath Fading Channels at High SNR

Koch, Tobias
Lapidoth, Amos
Description
This paper studies the capacity of discrete-time multipath fading channels. It is assumed that the number of paths is finite, i.e., that the channel output is influenced by the present and by the L previous channel inputs. A noncoherent channel model is considered where neither transmitter nor receiver are cognizant of the fading's realization, but both are aware of its statistic. The focus is on capacity at high signal-to-noise ratios (SNR). In particular, the capacity pre-loglog - defined as the limiting ratio of the capacity to loglog SNR as SNR tends to infinity - is studied. It is shown that, irrespective of the number paths L, the capacity pre-loglog is 1.
Comment: To be presented at the 2008 IEEE Symposium on Information Theory (ISIT), Toronto, Canada; replaced with version that appears in the proceedings
Keywords
Computer Science - Information Theory