A study on optimum weights for delay transmit diversity for DS-CDMA in a frequency non-selective fading channel

Akihito Katoh, Eisuke Kudoh, Fumiyuki Adachi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

In this paper, we study DS-CDMA delay transmit diversity that transmits the weighted and time-delayed versions of the same signal from multiple antennas in a frequency non-selective fading environment. At a receiver, one receive antenna is used and the received delayed signals are coherently combined by Rake receiver. The set of optimum antenna weights for maximizing the received signal-to-noise power ratio (SNR) is theoretically derived to reveal that the optimum solution is to transmit only from the best antenna that has the maximum channel gain. The bit error rate (BER) performance improvement over conventional delay transmit diversity is theoretically analyzed and confirmed by computer simulations. The combined effect of transmit diversity and transmit power control (TPC) is also evaluated. Furthermore, the impact of fading decorrelation between the transmit and receive channels is also investigated for both the time division duplex (TDD) and frequency division duplex (FDD) schemes.

Original languageEnglish
Pages (from-to)838-848
Number of pages11
JournalIEICE Transactions on Communications
VolumeE87-B
Issue number4
Publication statusPublished - 2004 Apr

Keywords

  • DS-CDMA
  • Fading
  • Rake combining
  • Transmit diversity
  • Transmit power control

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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