Capacity and power allocation for fading MIMO channels with channel estimation error

Taesang Yoo, Andrea Goldsmith

Research output: Contribution to journalArticlepeer-review

651 Scopus citations


In this correspondence, we investigate the effect of channel estimation error on the capacity of multiple-input-multiple-output (MIMO) fading channels. We study lower and upper bounds of mutual information under channel estimation error, and show that the two bounds are tight for Gaussian inputs. Assuming Gaussian inputs we also derive tight lower bounds of ergodic and outage capacities and optimal transmitter power allocation strategies that achieve the bounds under perfect feedback. For the ergodic capacity, the optimal strategy is a modified waterfilling over the spatial (antenna) and temporal (fading) domains. This strategy is close to optimum under small feedback delays, but when the delay is large, equal powers should be allocated across spatial dimensions. For the outage capacity, the optimal scheme is a spatial waterfilling and temporal truncated channel inversion. Numerical results show that some capacity gain is obtained by spatial power allocation. Temporal power adaptation, on the other hand, gives negligible gain in terms of ergodic capacity, but greatly enhances outage performance.

Original languageEnglish (US)
Pages (from-to)2203-2214
Number of pages12
JournalIEEE Transactions on Information Theory
Issue number5
StatePublished - May 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Information Systems
  • Computer Science Applications
  • Library and Information Sciences


  • Capacity
  • Channel estimation error
  • Feedback delay
  • Multiple-input-multiple-output (MIMO)
  • Mutual information
  • Outage capacity
  • Power allocation
  • Waterfilling


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