Relay Selection Scheme For Energy Harvesting Wireless Communication Systems

Generally, the nodes of traditional wireless sensor network are charged by the battery. The capacity of the battery is limited, which restricts the life cycle of wireless sensor networks. Thereby maximizing the life cycle of wireless sensor networks becomes a hot field of wireless networks, in which renewable energy harvesting technology combined with the wireless sensor network is a key research direction. Therefore, this thesis studies the energy management strategy of wireless sensor networks based on energy harvesting technology, and a new type of relay selection scheme is proposed based on node workload distribution, which can effectively prolong the life cycle of wireless sensor networks, and improve the system performance.In this thesis, we study the energy harvesting system of wireless communication and obtain some valuable results related to the aspects as below.1. The energy management strategy of single node wireless communication system based on energy harvesting is studied. According to the queueing theory, the stability of the single node system is derived. The simulation of various energy management strategies are carried out based on different data and energy arrival models, different energy and data mapping function, different cost functions and different buffer capacity. The simulation results show that the throughput and delay performance of different strategies are different in different situations.2. The relay selection scheme of multi node wireless communication system based on energy harvesting is studied. A relay selection algorithm based on workload assignment is proposed, which is compared with the simple relay rotation method and the real time relay selection method. When （?） is larger than δ_i, the relay selection method based on workload allocation is the optimal algorithm for throughput and delay performance, and reduces the complexity of the algorithm. The system delay of two different frames situations are compared. The longer work cycle of relay selection method will make the system delay shorter.3. The performance of different energy management strategies for the single node and multi node wireless communication systems based on energy harvesting is studied. The new energy management strategy with CSI can make the system more stable than the case without CSI, and can reduce the system delay, improve the system throughput, greatly improve the system performance. In the case of inefficient power, the stability of different strategies is significantly related to the storage efficiency β₁. The smaller β₁ will make system performance worse including worse system stability, longer system delay, smaller throughput.