TY - JOUR
T1 - On the Performance of Downlink NOMA in Underlay Spectrum Sharing
AU - Kumar, Vaibhav
AU - Ding, Zhiguo
AU - Flanagan, Mark F.
N1 - Funding Information:
Manuscript received September 17, 2020; revised December 24, 2020 and February 15, 2021; accepted March 15, 2021. Date of publication March 29, 2021; date of current version June 9, 2021. This work was supported in part by Science Foundation Ireland (SFI) under Grant 17/US/3445 and in part by European Regional Development Fund under Grant 13/RC/2077. The review of this article was coordinated by Prof. Daniel Benevides da Costa. (Corresponding author: Vaibhav Kumar.) Vaibhav Kumar and Mark F. Flanagan are with the School of Electrical and Electronic Engineering, University College Dublin, D04 V1W8 Dublin, Ireland (e-mail: [email protected]; [email protected]).
Publisher Copyright:
© 2021 IEEE.
PY - 2021/5
Y1 - 2021/5
N2 - Non-orthogonal multiple access (NOMA) and spectrum sharing are two potential technologies for providing massive connectivity in beyond fifth-generation (B5G) networks. In this paper, we present the performance analysis of a multi-antenna-assisted two-user downlink NOMA system in an underlay spectrum sharing system. We derive closed-form expressions for the average achievable sum-rate and outage probability of the secondary network under a peak interference constraint and/or peak power constraint, depending on the availability of channel state information (CSI) of the interference link between secondary transmitter (ST) and primary receiver (PR). For the case where the ST has a fixed power budget, we show that performance can be divided into two specific regimes, where either the interference constraint or the power constraint primarily dictates the performance. Our results confirm that the NOMA-based underlay spectrum sharing system significantly outperforms its orthogonal multiple access (OMA) based counterpart, by achieving higher average sum-rate and lower outage probability. We also show the effect of information loss at the ST in terms of CSI of the link between the ST and PR on the system performance. Moreover, we also present closed-form expressions for the optimal power allocation coefficient that minimizes the outage probability of the NOMA system for the special case where the secondary users are each equipped with a single antenna. A close agreement between the simulation and analytical results confirms the correctness of the presented analysis.
AB - Non-orthogonal multiple access (NOMA) and spectrum sharing are two potential technologies for providing massive connectivity in beyond fifth-generation (B5G) networks. In this paper, we present the performance analysis of a multi-antenna-assisted two-user downlink NOMA system in an underlay spectrum sharing system. We derive closed-form expressions for the average achievable sum-rate and outage probability of the secondary network under a peak interference constraint and/or peak power constraint, depending on the availability of channel state information (CSI) of the interference link between secondary transmitter (ST) and primary receiver (PR). For the case where the ST has a fixed power budget, we show that performance can be divided into two specific regimes, where either the interference constraint or the power constraint primarily dictates the performance. Our results confirm that the NOMA-based underlay spectrum sharing system significantly outperforms its orthogonal multiple access (OMA) based counterpart, by achieving higher average sum-rate and lower outage probability. We also show the effect of information loss at the ST in terms of CSI of the link between the ST and PR on the system performance. Moreover, we also present closed-form expressions for the optimal power allocation coefficient that minimizes the outage probability of the NOMA system for the special case where the secondary users are each equipped with a single antenna. A close agreement between the simulation and analytical results confirms the correctness of the presented analysis.
KW - Achievable rate
KW - nonorthogonal multiple access
KW - optimal
KW - outage probability
KW - power allocation
KW - underlay spectrum sharing
UR - http://www.scopus.com/inward/record.url?scp=85103775611&partnerID=8YFLogxK
U2 - 10.1109/TVT.2021.3069440
DO - 10.1109/TVT.2021.3069440
M3 - Article
AN - SCOPUS:85103775611
SN - 0018-9545
VL - 70
SP - 4523
EP - 4540
JO - IEEE Transactions on Vehicular Technology
JF - IEEE Transactions on Vehicular Technology
IS - 5
M1 - 9388912
ER -