In this work, although we have proposed an effective RS algorithm to mitigate the mul-tiuser interference, the performance such as BER and outage probability has not been analyzed. Making the derivation of the performance will complete the work, and the result can be used as another choice of the criterion for RS. Besides, as shown in the sim-ulation results, an error floor due to interference exists in high SNR regimes. Therefore, developing an algorithm which overcomes the presented performance limitation seems to be an promising issue.
As for multiuser two-way relaying systems employing CDMA, the future work might include power control. Power control is a critical problem in CDMA system because of near-far effect. If power control is not done in the system, the users with larger signal power tend to dominate the system, thus, the users with smaller power get worse perfor-mance. However, for simplicity, power control is out of scope in this work. In order to suppress the multiuser interference further and to achieve the better performance, how to perform power control is important in the future work.
Furthermore, developing a RS method to balance the received SINR might be an issue in the future work. As displayed in the simulation results, we can find that BER at the destination is much smaller than BER at the desired source node due to self-interference cancelation. Since more self-interference can be eliminated at the destination, it achieves more benefits from the operation compared to the desired source node. Therefore, it seems a little unfair to select a best relay based on max min criterion. Considering a RS method
that balance the SINR on both the desired source node and the destination might be an approach to promote the performance.
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