Coherent hybrid ds‐FFH CDMA‐basic performance in mobile radio environment

Shigeru Tomisato, Kazuhiko Fukawa, Hiroshi Suzuki

Research output: Contribution to journalArticlepeer-review


This paper proposes a coherent hybrid DS‐FFH CDMA system that combines the coherent frequency‐hopping (FFH) and the direct sequence (DS) techniques. the basic performance in the mobile radio system is analyzed. the proposed method features the following: (i) CDM by the low‐chip‐rate DS using the orthogonal codes; (ii) the frequency‐diversity effect obtained for each symbol by the maximum‐ratio synthesis of the multiple chips spread by the coherent FFH. The system configuration and the operation are described. Assuming a channel where the delayed wave components of the four waves contain respective Rayleigh fadings, a computer simulation is executed and the following transmission characteristics are revealed. (i) When there does not exist an interference wave in the 4‐chip system, the 4‐branch frequency‐diversity effect is verified. the average Eb/No required in order to realize the average BER of 10−2 is 8 dB. (ii) When space diversity is combined, the average Eb/No required to realize the average BER of 10‐2 is 8 dB, even if there exists an interference wave. (iii) In the dynamic fading environment, the maximum Doppler frequency that can realize the average BER of 10‐2 for the average Eb/No =15 dB, is 20 Hz and 80 Hz, respectively, for the cases with and without interference.

Original languageEnglish
Pages (from-to)103-114
Number of pages12
JournalElectronics and Communications in Japan (Part I: Communications)
Issue number4
Publication statusPublished - Apr 1995
Externally publishedYes


  • Mobile radio
  • code‐division multiple access (CDMA)
  • coherent combining
  • fast‐frequency hopping; direct sequence

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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