root mean square (rms) multipath delay spread is a good measure of bit-error-rate performance, i.e., as rms delay spread gets larger, bit-error-rate generally gets worse. However, it is pointed out that this is not always true, especially in propagation conditions with very long-delayed multipath signals. In short, it is the purpose of this paper to show examples that the facts believed to be true sometimes turn out to be false, unless we pay attention to both aspects of propagation and system design in the field of mobile/portable radio communications. In fact, for highly efficient communication systems design, propagation, antenna and system factors should be taken into account simultaneously." />


The Realities and Myths of Multipath Propagation

Susumu YOSHIDA  Mitsuhiko MIZUNO  

Publication
IEICE TRANSACTIONS on Communications   Vol.E76-B   No.2   pp.90-97
Publication Date: 1993/02/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Issue on Land Mobile/Portable Propagation)
Category: 
Keyword: 
multipath propagation,  fading,  delay spread,  

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Summary: 
In this paper, some misconceptions about "multipath propagation" are discussed for those propagation engineers, who are not familiar with the close relationship between multipath propagation and a communication system in a mobile/portable radio communication environment. It is shown that believed facts about multipath propagation are not always true. Namely, it is well-known that multipath propagation is undesirable if a conventional sample-and-decision receiver is assumed. It is not well-recognized that it can be a desirable phenomenon if a sophisticated communication system uses adaptive equalization, anti-multipath modulation, or spread spectrum communication, for example. On the other hand, it is widely accepted that root mean square (rms) multipath delay spread is a good measure of bit-error-rate performance, i.e., as rms delay spread gets larger, bit-error-rate generally gets worse. However, it is pointed out that this is not always true, especially in propagation conditions with very long-delayed multipath signals. In short, it is the purpose of this paper to show examples that the facts believed to be true sometimes turn out to be false, unless we pay attention to both aspects of propagation and system design in the field of mobile/portable radio communications. In fact, for highly efficient communication systems design, propagation, antenna and system factors should be taken into account simultaneously.