Differential Modulation for Asynchoronous.pdf (860.12 kB)
Download fileDifferential Modulation for Asynchronous Two-Way-Relay Systems over Frequency-Selective Fading Channels
journal contribution
posted on 2017-01-19, 00:00 authored by Ahmad Salim, Tolga M. DumanIn this paper, we propose two schemes for asynchronous multi-relay two-way relay (MR-TWR) systems in
which neither the users nor the relays know the channel state information (CSI). In an MR-TWR system, two users
exchange their messages with the help of NR relays. Most of the existing works on MR-TWR systems based on
differential modulation assume perfect symbol-level synchronization between all communicating nodes. However,
this assumption is not valid in many practical systems, which makes the design of differentially modulated schemes
more challenging. Therefore, we design differential modulation schemes that can tolerate timing misalignment under
frequency-selective fading. We investigate the performance of the proposed schemes in terms of either probability of
bit error or pairwise error probability. Through numerical examples, we show that the proposed schemes outperform
existing competing solutions in the literature, especially for high signal-to-noise ratio (SNR) values.