On the ergodic secrecy capacity of the wiretap channel under imperfect main channel estimation

Abstract
The ergodic secrecy capacity of the wiretap channel is known when the main channel (between the transmitter and the legitimate receiver) state information (CSI) is perfect at the transmitter and the coherence period is sufficiently large to enable random coding arguments in each block. In a fast fading scenario, when the codeword length spans many coherence periods, the secrecy capacity is still not known. In this paper, we present a framework that characterizes this secrecy capacity under imperfect main channel estimation at the transmitter. Inner and outer bounds on the ergodic secrecy capacity are derived for a class of independent identically distributed (i.i.d.) fading channels. The achievable rate is a simple on-off scheme using a Gaussian input. The upper bound is obtained using an appropriate correlation scheme of the main and the eavesdropper channels. The upper and the lower bounds coincide with recently derived ones in the perfect main CSI extreme. Furthermore, the lower bound matches the upper bound in no main CSI extreme, where the secrecy capacity is equal to zero. Numerical results are provided for independent identically distributed (i.i.d.) Rayleigh fading channels. © 2011 IEEE.

Citation
Rezki, Z., Khisti, A., & Alouini, M.-S. (2011). On the ergodic secrecy capacity of the wiretap channel under imperfect main channel estimation. 2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR). doi:10.1109/acssc.2011.6190151

Publisher
Institute of Electrical and Electronics Engineers (IEEE)

Journal
2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR)

Conference/Event Name
45th Asilomar Conference on Signals, Systems and Computers, ASILOMAR 2011

DOI
10.1109/ACSSC.2011.6190151

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