Transparent inband feedback for training-based MIMO systems

Oussama Souihli, Tomoaki Ohtsuki

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Recently, Echo-MIMO, a delay-free feedback scheme has been proposed for Closed-Loop MIMO systems, where the receiver echoes the received signal on the fly to the transmitter without any processing. While this reduced feedback latency allows for more use of the channel's coherence time for data transmission, it comes at high power-and-bandwidth costs, as two MIMO transmissions are required in the feedback phase. In this paper, we present a feedback scheme that preserves the advantages of Echo-MIMO while requiring only one feedback transmission. The echoed signals are judiciously combined with the receiver's signals such that their separation at the transmitter be lossless, and that no extra transmit power nor bandwidth be required. In addition, we highlight the estimation accuracy degradation in Echo-MIMO owing to the echoed noise, and analytically confirm the intuition that removing the noise prior to echoing the received signal provides better estimation than echoing the noisy received signal as is and later account for the noise effect upon echo reception. Simulation results show that the proposed scheme outperforms Echo-MIMO in terms of channel estimation accuracy and achievable capacity of up to 5 dB and 10 bit/sec/Hz, respectively.

Original languageEnglish
Title of host publication2010 IEEE 71st Vehicular Technology
Publication statusPublished - 2010 Jul 30
Event2010 IEEE 71st Vehicular Technology Conference, VTC 2010-Spring - Taipei, Taiwan, Province of China
Duration: 2010 May 162010 May 19

Publication series

NameIEEE Vehicular Technology Conference
ISSN (Print)1550-2252


Other2010 IEEE 71st Vehicular Technology Conference, VTC 2010-Spring
Country/TerritoryTaiwan, Province of China

ASJC Scopus subject areas

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


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