Optimal power allocation over fading channels with stringent delay constraints

Xiangheng Liu, Andrea J. Goldsmith

Research output: Contribution to journalConference articlepeer-review

28 Scopus citations


We study the optimal power allocation scheme for i.i.d. block-fading channels [1] with a strict transmission delay constraint. In particular, we consider the maximization of the total throughput within a finite interval under a short-term average power constraint. When all the channel gains are known apriori, we demonstrate the mapping between the delay-constrained channel and the corresponding parallel channel for which both the single-user and multi-user channel results are well-known. The maximization problem becomes more complicated when only causal channel side information (CSI) is available. We show that under this assumption, constant power transmission is optimal in the limit of high signal-to-noise ratio (SNR). We also examine the optimal power policy and show that a simple linear power control scheme has near optimal performance. We next consider a two-user broadcast channel with a stringent delay constraint and causal feedback. We solve the optimal power control problem for this channel via dynamic programming. We discuss the solutions in the limit of both low and high SNR. Numerical results show the optimal scheme is approximately piece-wise linear for general SNRs.

Original languageEnglish (US)
Pages (from-to)1413-1418
Number of pages6
JournalIEEE International Conference on Communications
StatePublished - 2002
Externally publishedYes
Event2002 International Conference on Communications (ICC 2002) - New York, NY, United States
Duration: Apr 28 2002May 2 2002

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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