Optimal Power Policy and Throughput Analysis in Cognitive Broadcast Networks Under Primary's Outage Constraint
This paper focuses on a spectrum-sharing based cognitive radio fading Broadcast Channel (BC) with a single-antenna Secondary Base Station (SBS) and M Secondary Receivers (SRs) concurrently utilizing the same spectrum band with one delay-sensitive Primary User (PU). The quality-of-service requirement in the primary network is given by the Primary user's Outage probability Constraint (POC). The authors address the optimal power allocation problem for the Ergodic Sum Capacity (ESC) maximization in the secondary BC network subject to a POC and an average transmit power constraint at SBS. Optimality conditions reveal that in each fading block SBS will choose only one SR with the highest channel power gain and allocate the block to that user.