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Impact of channel estimation errors and power allocation on analog network coding and routing in two-way relaying

Tabataba, F. S ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1109/TVT.2012.2201969
  3. Publisher: IEEE , 2012
  4. Abstract:
  5. In this paper, we study two important transmission strategies in full-duplex two-way relaying in the presence of channel estimation errors. In analog network coding (ANC), the relay transmits the combined signals that were received from both sources, with the aim of achieving better spectral efficiency. However, due to imperfect channel-state information (CSI), sources cannot perfectly cancel their own data in the relayed signal. We derive an achievable information rate for ANC in imperfect-CSI conditions and show how the ANC performance can significantly be degraded as a result. Moreover, we derive cut-set bounds with channel estimation errors for traditional routing (TR), in which time sharing is used at the relay. Although it has been previously shown that ANC outperforms TR when the CSI is perfect, we find that it may not maintain its superiority in imperfect-CSI case at low signal-to-noise ratio (SNR) conditions. Next, we propose practical power allocation techniques that can be used in the sources and relay for both ANC and TR. The proposed power allocation schemes are relatively simple to compute and rely only on long-term channel statistics. Nevertheless, they are shown to be effective and close to optimal solutions for a wide range of SNRs, to different positions of the relay, and for both perfect- and imperfect-CSI conditions. By using the proposed power allocation techniques, it is possible to bring back advantages of ANC over TR for a wide range of SNRs in imperfect-CSI conditions
  6. Keywords:
  7. channel-state information (CSI) ; Rayleigh fading channels ; Achievable information rate ; Analog network coding ; Analog network coding (ANC) ; capacity ; Channel estimation errors ; Channel statistics ; Cut-set bound ; Full-duplex ; Impact of channel estimation error ; Low signal-to-noise ratio ; Optimal solutions ; Power allocations ; Power Optimization ; routing ; Spectral efficiencies ; Time-sharing ; Transmission strategies ; Two-way relaying ; Channel estimation ; Errors ; Network coding ; Rayleigh fading ; Spectrum analyzers ; Channel state information
  8. Source: IEEE Transactions on Vehicular Technology ; Volume 61, Issue 7 , May , 2012 , Pages 3223-3239 ; 00189545 (ISSN)
  9. URL: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6209447