CAJ | 학술논문

在传感器网络中，降低网络总功耗和延长网络寿命是网络设计和优化的重--求。本文研究了采用机会性中继选择的解码前传系统，提出了一种能提高系统功率效率的中继选择、调制方式和发送功率的联合优化方案。该方案中，源节点和中继节点使用不同的发送功率。在给定误码率和系统参数的条件下，可以通过分布式的计算方法获得最优解。仿真结果表明所提方案能获得比协作 MIMO 系统更高的功率效率。
재전감기망락중，강저망락총공모화연장망락수명시망락설계화우화적중--구。본문연구료채용궤회성중계선택적해마전전계통，제출료일충능제고계통공솔효솔적중계선택、조제방식화발송공솔적연합우화방안。해방안중，원절점화중계절점사용불동적발송공솔。재급정오마솔화계통삼수적조건하，가이통과분포식적계산방법획득최우해。방진결과표명소제방안능획득비협작 MIMO 계통경고적공솔효솔。
For sensor networks,maximizing the network lifetime is the main concern.Since sensor networks are mainly designed to cooperate on some joint task,the design intention is to minimize the total energy consumption in the network instead of minimizing energy consumption of individual nodes.In repetition-based cooperative diversity schemes,each relay requires its own subchannel for repetition.Therefore,full spatial diversity benefit comes at a price of decreasing bandwidth efficiency with the number of cooperating relays.Moreover,total circuit energy consumption also increases with the number of active relays.Especially in short-range applications,the circuit energy consumption is comparable to or even dominates the transmission energy.A simplified technique to achieve spatial diversity in cooperative networks is the opportunistic relaying scheme.The basic idea is to choose the best relay node amongst all available relays through a certain policy.On the other hand,energy and spectral efficiency can be enhanced by employing adaptive transmission techniques,which could fully utilize the time-varying wireless channels by adj usting transmission parameters,such as transmission power and constellation size. In this work,we propose a relay selection scheme to minimize the total energy consumption,which includes both the transmission energy and the circuit energy consumption.The energy efficiency for orthogonal opportunistic decode-and-forward(DF)relaying is improved by optimizing transmit power,rate and relay selection jointly.The proposed scheme allows source and relay nodes to transmit information using different transmit power.Given the target bit-error-rate(BER)and system parameters,the optimization problem involving transmit powers,modulation formats and the relay selection is solved in a distributed manner.The numerical results indicate the proposed scheme can achieve more energy saving than the cooperative MIMO transmission and reception.