Impact of Synchronization Errors on the Performance of ACO-OFDMA Signaling for Medical Extra-WBAN Links

This paper considers the use of infrared-based optical wireless communications for multi-user uplink wireless body-area networks. We propose the use of optical-orthogonal frequency division multiple access (O-OFDMA) signaling to manage the multiple access (MA) requirement for relatively high-rate medical applications. In particular, we consider asymmetrically clipped O-OFDMA and analyze its performance in terms of bit-error-rate and outage probability in the presence of multi-user time synchronization errors. These latter may occur due to mobility and random transmitter orientations, and will impact the link performance by inducing MA interference (MAI). We show that the effect of MAI increases with increasing the data rate. For instance, for 1 and 2 Mbps data rates, to achieve a target bit-error-rate of 10−3, the link distance is limited to 1.9 and 1 m, respectively, compared to 2.2 and 1.8 m in the absence of MAI.