Optimal training for residual self-interference for full-duplex one-way relays

Xiaofeng Li, Cihan Tepedelenlioglu, Habib Senol

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Channel estimation and optimal training sequence design for full-duplex one-way relays are investigated. We propose a training scheme to estimate the residual self-interference (RSI) channel and the channels between nodes simultaneously. A maximum likelihood estimator is implemented with the Broyden-Fletcher-Goldfarb-Shanno algorithm. In the presence of RSI, the overall source-to-destination channel becomes an inter-symbol-interference (ISI) channel. With the help of estimates of the RSI channel, the destination is able to cancel the ISI through equalization. We derive and analyze the Cramer-Rao bound (CRB) in closed-form by using the asymptotic properties of Toeplitz matrices. The optimal training sequence is obtained by minimizing the CRB. Extensions for the fundamental one-way relay model to the frequency-selective fading channels and the multiple relays case are also considered. For the former, we propose a training scheme to estimate the overall channel, and for the latter the CRB and the optimal number of relays are derived when the distance between the source and the destination is fixed. Simulations using LTE parameters corroborate our theoretical results.

Original languageEnglish (US)
Article number8434253
Pages (from-to)5976-5989
Number of pages14
JournalIEEE Transactions on Communications
Issue number12
StatePublished - Dec 2018


  • Full-duplex relays
  • Toeplitz matrix
  • frequency-selective channels
  • maximum likelihood estimation
  • multiple relays
  • optimal training sequence
  • residual self-interference

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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