Adaptive PSAM accounting for channel estimation and prediction errors

Xiaodong Cai, Georgios B. Giannakis

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


Adaptive modulation requires channel state information (CSI), which can be acquired at the receiver by inserting pilot symbols in the transmitted signal. In this paper, we first analyze the effect linear minimum mean square error (MMSE) channel estimation and prediction errors have on bit-error rate (BER). Based on this analysis, we develop adaptive pilot symbol assisted modulation (PSAM) schemes that account for both channel estimation and prediction errors to meet a target BER. While pilot symbols facilitate channel acquisition, they consume part of transmitted power and bandwidth, which in turn, reduces spectral efficiency. With imperfect (and thus, partial) CSI available at the transmitter and receiver, two questions arise naturally: how often should pilot symbols be transmitted, and how much power should be allocated to pilot symbols. We address these two questions by optimizing pilot parameters to maximize spectral efficiency.

Original languageEnglish (US)
Pages (from-to)246-256
Number of pages11
JournalIEEE Transactions on Wireless Communications
Issue number1
StatePublished - Jan 2005


  • Adaptive modulation
  • Channel estimation
  • Channel prediction
  • Rayleigh fading

ASJC Scopus subject areas

  • Engineering(all)
  • Computer Networks and Communications


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