Title :
On the relationship between the multi-antenna secrecy communications and cognitive radio communications
Author :
Zhang, Lan ; Zhang, Rui ; Liang, Ying-Chang ; Xin, Yan ; Cui, Shuguang
Author_Institution :
Dept. of Electr. & Comput. Eng., Nat. Univ. of Singapore, Singapore, Singapore
fDate :
6/1/2010 12:00:00 AM
Abstract :
This paper studies the achievable rates of the multi-antenna or multiple-input multiple-output (MIMO) secrecy channel with multiple single-/multi-antenna eavesdroppers. By assuming Gaussian input, the maximum achievable secrecy rate is obtained with the optimal transmit covariance matrix that maximizes the minimum difference between the channel mutual information of the secrecy user and those of the eavesdroppers. The maximum secrecy rate computation can thus be formulated as a non-convex max-min problem, which cannot be solved efficiently by existing methods. To handle this difficulty, this paper explores a new relationship between the secrecy channel and the recently developed cognitive radio (CR) channel, in which the secondary user transmits over the same spectrum simultaneously with multiple primary users, subject to the received interference power constraints at the primary users, or the so-called "interference temperature (IT)" constraints. By constructing an auxiliary multi-antenna CR channel that has the same channel responses as the secrecy channel, this paper shows that the optimal transmit covariance to achieve the maximum secrecy rate is the same as that to achieve the CR spectrum sharing capacity with properly selected IT constraints. Thereby, finding the optimal complex transmit covariance matrix for the secrecy channel becomes equivalent to searching over a set of real IT constraints in the auxiliary CR channel. Based on this relationship, efficient algorithms are proposed to solve the non-convex secrecy rate maximization problem by transforming it into a sequence of convex CR spectrum sharing capacity computation problems, under various setups of the secrecy channel.
Keywords :
MIMO communication; antenna arrays; cochannel interference; cognitive radio; covariance matrices; telecommunication security; wireless channels; CR spectrum sharing capacity; Gaussian input; cognitive radio communication; interference temperature constraints; maximum secrecy rate computation; multiantenna secrecy communication; multiple antenna eavesdroppers; multiple-input multiple-output secrecy channel; optimal transmit covariance matrix; single antenna eavesdroppers; Chromium; Cognitive radio; Communications Society; Covariance matrix; Interference constraints; MIMO; Mutual information; National electric code; Temperature; Upper bound; Cognitive radio, convex optimization, interference temperature, multi-antenna systems, secrecy capacity.;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2010.06.090063