A cross-layer perspective on energy harvesting aided green communications over fading channels
A cross-layer perspective on energy harvesting aided green communications over fading channels
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DOI：
10.1109/tvt.2014.2329854
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
Tian Zhang;Wei Chen-;Zhu Han;Z. Cao
中科院分区：
文献类型：
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作者：
Tian Zhang;Wei Chen-;Zhu Han;Z. Cao
本文考虑能量收集绿色网络中物理层的功率分配和上层应用层的缓冲延迟。我们分析了衰落信道下的延迟最优功率分配问题。可靠传输所需的总功率包括传输功率和电路功率。收集的电力（其存储在电池中）和电网电力构成电力资源。目标是在平均电网功率的约束下，找到一种最小化缓存延迟的策略。该策略是一个二维向量的传输速率和电池的功率分配作为其元素。在每次传输中，发射机决定传输速率和从电池分配的功率（所需功率的其余部分将由电网提供）。当数据到达过程、收获能量到达过程和信道过程均为马尔可夫过程时，建立了一个约束马尔可夫决策过程（MDP）问题。我们证明，最优策略可以得到如下。首先，我们通过一个简化的MDP问题来求解最优速率，该问题只与平均收获能量有关，而与收获能量到达过程无关。其次，可以基于最优速率给出电池的功率分配。通过将约化的MDP问题转化为平均费用MDP和折扣最优MDP，得到了最优策略的一些结构性质。此外，得到了独立同分布（i.i.d.）例
In this paper, we consider the power allocation of the physical layer and the buffer delay of the upper application layer in energy harvesting green networks. We analyze the delay-optimal power allocation problem over fading channels. The total power required for reliable transmission includes the transmission power as well as the circuit power. The harvested power (which is stored in a battery) and the grid power constitute the power resource. The objective is to find a policy to minimize the buffer delay under the constraint on the average grid power. The policy is a two-dimensional vector with the transmission rate and the power allocation of the battery as its elements. In each transmission, the transmitter decides the transmission rate and the allocated power from the battery (the rest of the required power will be supplied by the power grid). A constrained Markov decision process (MDP) problem is formulated when the data arrival process, the harvested energy arrival process, and the channel process are Markov processes. We prove that the optimal policy can be obtained as follows. First, we solve the optimal rate through a reduced MDP problem that is only related to the average harvested energy but not the harvested energy arrival process. Second, the battery's power allocation can be given based on the optimal rate. By analyzing the reduced MDP problem through the transformations to the average cost MDP and discount optimal MDP, we derive some structural properties of the optimal policy. Moreover, the closed-form expression is obtained for the independent and identically distributed (i.i.d.) cases.