Despite almost two decades of research, multiple challenges remain unresolved in Cognitive Radio (CR) scenarios, especially the fundamental problem of reliable spectrum sensing. Hence we propose a channel partitioning scheme (CPS) based CR relying on realistic imperfect spectrum sensing. The channels licensed to the primary user (PU) are partitioned into two sets. Channels in one of the sets are exclusively reserved for the PU, while those in the other can be accessed by both the PU and the secondary user (SU) after spectrum sensing. The PU prioritizes its transmissions over the two sets by first transmitting using the channels in the reserved set and then moves on to the unreserved set, if required. It is shown that this simple policy significantly improves the overall detection performance as well as the simultaneous achievable rates and reduces the overhead associated with sensing.
Abstract-A new information-theoretic model is proposed for5 underlay-based cognitive radio (CR), which imposes rate limita-6 tion on the secondary user (SU), whereas the traditional systems
In this paper, we introduce the Cognitive Multiple Access Z Interference Channel (CMAZIC) where there are two secondary user (SU) transmitters and one SU receiver and one primary user (PU) transceiver pair. Both the SUs are aware of the PU message non causally. There is interference only from the PU transmitter to the SU receiver but not vice versa . We study the Discrete Memoryless CMAZIC (DM-CMAZIC) and provide achievable rate regions with and without superposition coding at the PU transmitter and with Gelfand Pinsker coding against the interference of the PU at both the SU transmitters. For the Gaussian case we show that the inner bound without superposition coding is capacity achieving when appropriate Dirty paper coding is performed at the SU transmitters.
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