Performance Analysis of Buffer-Aided Relaying Implant WBAN

In conventional cooperative implant wireless body area networks (WBAN), the path loss of in-body channel is much larger than that of on-body channel, thus the system reliability is always limited by the in-body link. The reason is that the on-body relay of the above system uses a fixed schedule for data reception and transmission without considering the quality of the channel. To further achieve low-power consumption of the implant sensor node, a buffer-aided relaying implant WBAN is considered in this paper, where an on-body relay is equipped with a data buffer. Two link-selection protocols, namely Protocol 1 and Protocol 2, are investigated, which can adopt an adaptive schedule for reception and transmission. For both protocols, Gauss-Hermite quadrature and linear-approximation methods are used to derive the closed-form bit-error-rate (BER) and average delay expressions. Theoretical and simulated results show that the Protocol 2 has higher delay compared with the Protocol 1 under the same parameters while the Protocol 2 can achieve significantly better BER performance than the Protocol 1. Furthermore, we reveal that, the BER performance of the Protocol 2 is independent of the buffer size, and through giving a small buffer size the Protocol 2 can achieve lower power consumption at the cost of a slight delay.