基于无率码的信息与能量同传中继信道传输速率的优化与实现

Optimization and realization of SWIPT relay channel transmission rate based on rateless code

研究了信息与能量同传中继信道传输速率的优化与实现。系统模型为三节点两跳中继模型,中继采用解码转发协议进行转发。一个完整的传输分为2个阶段,第一阶段为源到中继的传输,为信息与能量同时传输,中继对接收到的信号进行功率分裂,一部分信号用于信息译码,另一部分信号转换为电能用作第二阶段的信息转发;第二阶段为中继采用译码转发方式转发信息。采用两跳不等时长,在传输信息量一定的条件下,以最小化两跳传输总时间为目标对功率分裂因子进行优化。在优化结果的基础上,采用Raptor码和不同调制方式的组合实现两跳不同的传输速率,最大化地利用两跳不同的信道容量,给出了Raptor码码长和调制方式的选择机制。仿真证明,两跳不等时长的安排可以获得更高的吞吐量,而采用Raptor码可实现对信道容量的充分利用和信息高效而可靠的传输。

The optimization of the transmission rate and implementation of the simultaneous wireless information and power transfer in a relay system were studied. In a three-node two-hop system, the decode-and-forward protocol was em- ployed by the relay node. One transmission period was divided into two phases. The first phase was the simultaneous transmission of the information and energy from the source to the relay. The received signal at the relay node was split to two parts. One part was used for information decoding, and the other was converted into energy for information forward- ing in the second phase. In the second phase, the information was forwarded according to the decode-and-forward proto- col by the relay. The power splitting factor was optimized to minimize the total time of the two hops for the transmission of a certain amount of information when the durations of the two hops were unequal. Furthermore, Raptor codes were combined with different modulation modes to realize different transmission rates on the two hops for the efficient utiliza- tion of the different channel capacities in the two hops. The selection mechanism of the codeword length of Raptor codes and modulation mode was given. The simulation proves that the two hops with unequal durations can achieve a higher throughput, and the capacity of the relay channel can be efficiently used by employing Raptor codes, and an efficient and reliable transmission is realized.