2 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 2 / 2
Yayın Achievable rates for the three user cooperative multiple access channel(IEEE, 2008) Edemen, Çağatay; Kaya, OnurFor a three user Gaussian multiple access channel (MAC), we propose a new superposition block Markov encoding based cooperation scheme. Our scheme allows the three users to simultaneously cooperate both in pairs, and collectively, by dividing the transmitted messages into sub messages intended for each cooperating partner. The proposed encoding and decoding at the transmitters take into account the relative qualities of the cooperation links between the transmitters. We obtain and evaluate the achievable rate region based on our encoding strategy, and compare it with the achievable rates for the two user cooperative MAC. We demonstrate that the added diversity by the presence of the third user improves the region of achievable rates, and this improvement is especially significant as far as the sum rate of the system is concerned.Yayın Delay tolerant cooperation in the energy harvesting multiple access channel(IEEE, 2016) Kaya, Onur; Su, Nuğman; Ulukuş, Şennur; Koca, MutluWe consider the optimum transmit scheduling problem for a two user energy harvesting cooperative multiple access channel. We assume a slotted model where energy harvests in each slot are known a priori. We propose a delay tolerant cooperation model: the transmitters create common information in a given slot, but need not cooperatively send the created common information immediately; they may relegate all or part of the cooperative message transmission to upcoming slots. We propose a modified block Markov superposition coding scheme based on message re-partitioning, that spans multiple slots. We characterize the corresponding achievable departure region by a deadline, and maximize it subject to energy harvesting constraints. We show that, delay tolerant cooperation need not necessarily improve the departure region over delay constrained cooperation, and derive a sufficient condition for the equivalence of the two policies. We compare optimal delay constrained and delay tolerant cooperation policies, and their achievable departure regions via simulations.
