Cooperative Transmission And Random Energy Suppling In Wireless Multicast

Considering the constrain of the transmission rate in multicast communication,a full-duplex(FD)receiver cooperative communication scheme is proposed.Meanwhile,the multicast transmission powered by energy harvesting is more environmental friendly and convenient than conventional multicast transmission.Thus,this thesis also study energy harvesting communication for multicast transmission.There are two areas of the study for the multicast transmission:1)Full-duplex(FD)receiver cooperative communications scheme for multicast transmissions,2)energy harvesting communication for multicast transmissions.1)A FD receiver cooperative communication scheme is proposed that one transmit-ter sends common message to two FD receivers,and the two FD receivers forward them received signal to them counterpart by the amplify-and-forward(AF)relaying scheme.At same time,each FD receiver receives the message from the transmitter and its coun-terpart.However,the scheme will bring the accumulation of the residual self-interference and the additive noise(RIAN)Therefore,an optimal power allocation should be derived to obtain the maximum achievable rate.First,when the channel gains from the transmit-ter to the two receivers,respectively,are the same,this paper proves that the transmission without cooperation is optimal.Then,when the channel gains from the transmitter to the two receivers,respectively,are different,this paper shows that the unilateral cooperative transmission mode(i.e.,only one receiver can forward its received signal to its coun-terpart)is optimal,and a numerical algorithm is proposed to obtain the optimal power allocation in this mode.2)This thesis considers a multicast channel with the transmitter powered by random energy harvester,for which the energy arrival process is stochastic,and the save-then-transmit scheme is adopted due to the battery half-duplex constraint:The transmitter first harvests energy for a certain time,and then stops EH to transmit information with all the accumulated energy at the battery.Obviously,it is crucial to determine a proper stop-ping time for EH,since larger EH duration provides more accumulated energy while it may decrease the average throughput.Our goal is to obtain the optimal stopping time to maximize the average throughput of the considered EH systems.First,considering the Gaussian channel scenario,this thesis proves the existence of the optimal stopping rule and shows that this rule has a state-dependent "threshold-based" structure under the Markov energy arrival case.Then,for the independent and identically distributed(i.i.d.)energy arrival case,this thesis further proves that the corresponding threshold is a constant and can be efficiently computed by a proposed algorithm.Finally,this thesis generalizes the researchs to the fading channel scenario and obtains the corresponding optimal stopping rule,which can be computed by a recursive algorithm.This thesis study the FD receiver cooperative communication and EH communica-tion for multicast transmissions,which can be used in content-centric wireless networks,digital broadcast and wireless sensor networks,and is more environmental friendly.