In this correspondence, we study the secure multiantenna transmission withartificial noise (AN) under imperfect channel state information in the presenceof spatially randomly distributed eavesdroppers. We derive the optimalsolutions of the power allocation between the information signal and the AN forminimizing the secrecy outage probability (SOP) under a target secrecy rate andfor maximizing the secrecy rate under a SOP constraint, respectively. Moreover,we provide an interesting insight that channel estimation error affects theoptimal power allocation strategy in opposite ways for the above twoobjectives. When the estimation error increases, more power should be allocatedto the information signal if we aim to decrease the rate-constrained SOP,whereas more power should be allocated to the AN if we aim to increase theSOP-constrained secrecy rate.
展开▼
