Kaya, Onurİşleyen, Murat2021-06-182021-06-182012Kaya, O. & İşleyen, M. (2012). Power control in the cognitive cooperative multiple access channel. Paper presented at the 46th Annual Conference on Information Sciences and Systems, 1-5. doi:10.1109/CISS.2012.6310802978146733140197814673313959781467331388https://hdl.handle.net/11729/3158http://dx.doi.org/10.1109/CISS.2012.6310802We extend several encoding and decoding techniques from cooperative communications framework, to a cognitive radio system consisting of a primary user (PU) and a secondary user (SU), sending their messages to a common receiver. Assuming that the transmitters and the receiver have full channel state information (CSI) collected and distributed by the common receiver, and that the SU knows the PU's codebook, the cooperation is obtained by block Markov superposition coding, and backwards decoding, which yield a causal overlay scenario. We formulate two rate optimization problems with the aim of, (i) maximizing the sum rate of the system, and (ii) maximizing the rate of the secondary user. We obtain the optimal power allocations for both cases, and the resulting rate regions. The power controlled cooperation turns out to be especially useful when maximizing the sum rate of the system, as it gives the PU significant rate rewards for allowing the cognitive transmitter to access its resources.eninfo:eu-repo/semantics/closedAccessAttribution-NonCommercial-NoDerivs 3.0 United StatesBackwards decodingBlock codesBlock Markov superposition codingChannel codingChannel state informationCodebooksCognitive cooperative multiple access channelCognitive radioCognitive radio systemCognitive transmitterCommunication channels (information theory)Cooperative communicationCooperative communicationsCooperative multiple accessDecodingDecoding techniquesEncodingEncoding and decodingEncoding techniquesFadingInformation scienceInterferenceMarkov processesMulti-access systemsNoiseOptimal power allocationOptimizationOptimization problemsPower controlPower controlledPower controlled cooperationPrimary userRadio receiversRadio transmittersReceiverRelaysSecondary userSum-rateSuper-position codingTelecommunication controlTransmittersConference Object1510.1109/CISS.2012.6310802