Broadband Space Diversity for Digital Microwave Radio Systems

Osamu KAGAMI  Kazuji WATANABE  Teruaki YOSHIDA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E81-B   No.1   pp.82-88
Publication Date: 1998/01/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Radio Communication
Keyword: 
digital microwave radio,  space diversity,  inband amplitude dispersion,  signal power,  three-ray model,  

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Summary: 
A new broadband space diversity (B-SD) combining method, which is a key technique in the growth of digital microwave radio system, is proposed. In this B-SD combining method, two received signals, whose bandwidths are 280 MHz, are combined. To develop this combining method, an optimum control algorithm is developed that monitors power levels of all primary carriers and controls the endless phase shifter so that the higher level signal is decreased and the lower level signal is increased. This paper describes the proposed B-SD combining method which effectively operates over a wide bandwidth. Performance evaluations based on simulations and theoretical estimations are given. It is proven that this combining method offers the same performance obtained by the conventional narrowband SD combining method and can be applied to over 50% cases of the propagation paths observed in Japan. The suitability of the proposed combining method and the calculation methods adopted is demonstrated experimentally.