On the Performance of Downlink Multiuser Cognitive Radio Inspired Cooperative NOMA
- 94 Downloads
This paper is considered as an application of a centralized control non orthogonal multiple access (NOMA) based cognitive radio network. Here, a base station (BS) sends simultaneously two information signals by employing the superposition coding scheme to two different types of users, i.e., group of near users and one far user. The near users, namely, the secondary users, exchange cooperatively their own received information among themselves ensuring the realization of maximal diversity gain. Besides, they are responsible for relaying information to the far user, namely, the primary user. One potential secondary user is selected to decode and forward the BS information signal to the primary user and the rest of the secondary users to reinforce the reliability, as well as, mitigate the non-decodable messages. Two equivalent cases of a relay (secondary user) selection scheme are proposed. In the first case, the selection aims at maximizing the minimum of the joint secondary to secondary (S to S) and secondary to primary (S to P) channels’ coefficients under a certain limit of interference condition. In the second case, the selection aims at maximizing the minimum of the BS to S and S to S paths while a certain quality of service of the primary user is strictly guaranteed. Assuming Rayleigh fading channels, new closed form expressions are derived for the achievable capacity associated with the two information signals. Simulation results reveal the advantage of our proposed schemes over the conventional orthogonal max–min approach and confirm the validity of our analysis.
KeywordsCooperative relaying system (CRS) Non-orthogonal multiple access (NOMA) Cognitive radio
- 2.Saito, Y., Benjebbour, A., Kishiyama, Y., & Nakamura, T. (2013). System level performance evaluation of downlink non-orthogonal multiple access (NOMA). In Proceedings of IEEE annual symposium on personal indoor mobile radio communications (PIMRC), London, U.K., (pp. 611–615).Google Scholar
- 3.Saito, Y., Kishiyama, Y., Benjebbour, A., Nakamura, T., Li, A., & Higuchi, K. (2013). Non-orthogonal multiple access (NOMA) for cellular future radio access. In Proceedings of IEEE vehicle technology conference, Dresden, Germany.Google Scholar
- 4.Ding, Z., Fan, P., & Poor, V. (2015). Impact of user pairing on 5G non-orthogonal multiple access downlink transmissions. IEEE Transactions on Vehicle Technology 99, 1.Google Scholar
- 6.Al-Imari, M., Xiao, P., Imran, M., & Tafazolli, R. (2014). Uplink non-orthogonal multiple access for 5G wireless networks. In Proceedings on 11th international symposium wireless communication systems (ISWCS), (pp. 781–785).Google Scholar
- 8.Wei, Z., Yuan, J., Ng, D.W.K., Elkashlan, M., & Ding, Z. (2016). A survey of downlink non-orthogonal multiple access for 5G wireless communication networks. arXiv:1609.01856v1 [cs.IT].Google Scholar
- 20.Zhang, J., et al. (2017). Performance analysis of relay assisted cooperative non-orthogonal multiple access systems. Submitted to IEEE Wireless Communication Letters.Google Scholar
- 21.Xu, P., Ding, Z., Dai, X., & Poor, H. (2015). NOMA: An information theoretic perspective,” [Online]. http://arxiv.org/abs/1504.07751.