Spreading and power allocation for multiple antenna transmission using decorrelating receivers

Dinesh Rajan, Elza Erkip, Behnaam Aazhang

Research output: Contribution to journalArticle

Abstract

We propose a new scheme for multiple antenna transmission in the context of spread-spectrum signaling. The new scheme consists of using shifted Gold sequences to modulate independent information on the multiple antennas. We show that this strategy of using multiphase spreading (MPS) on different antennas greatly improves the throughput over currently known spread-spectrum multiple-antenna methods. We also find the optimal power allocation strategy among multiple transmit antennas for a fixed rate of channel state information, which might be provided via a feedback link, at the transmitter. We demonstrate the differences in optimal power distribution for maximizing capacity and minimizing probability of outage. When the transmission from the two antennas uses orthogonal spreading, we find that optimizing the power does not give much gain over the equal power transmission. However, when the transmissions are not orthogonal as in the case of MPS, then allocating power to maximize throughput gives considerable gain over equal power transmission. We also consider the effect of imperfections in the feedback channel on the optimal power allocation and show that our power allocation scheme is robust to feedback errors.

Original languageEnglish (US)
Pages (from-to)436-445
Number of pages10
JournalIEEE Transactions on Wireless Communications
Volume2
Issue number3
DOIs
StatePublished - May 1 2003

Keywords

  • Code-division multiple access (CDMA)
  • Gold sequences
  • Multiple antennas
  • Multiuser detection
  • Outage probability
  • Power control

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics

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