研究成果：Effectiveness, fairness and social welfare maximization: service rules for the interrupted secondary users in cognitive radio networks

作者：张钰，Jinting Wang(通讯作者)

发表期刊：Annals of Operations Research（ABS3）

Cognitive radio networks that accommodate primary users (PUs) and secondary users (SUs) are usually modeled using a queueing system that gives PUs absolute priority over SUs. Under the back-off protocol, if a PU enters a band that is currently in use by an SU, the SU’s transmission is interrupted and the interrupted SU either (1) stays on the band ready to resume service after the PU’s transmission ends, (2) reattempts to associate with the current band at a later time (ISR), or (3) gets discarded by the system (ISD). In this paper, we compare these three service mechanisms from the perspectives of (a) effectiveness (i.e., the throughput of PU requests), (b) fairness among SUs and (c) the social welfare of the system. We first consider a system with non-strategic SUs to procure the system characteristics with which to make comparisons. The counterpart system with strategic SUs is then investigated, which includes SU joining strategies for both cooperative and non-cooperative scenarios. Our comparison results indicate that when SUs are non-strategic the ISD mechanism performs best. When SUs are strategic (i.e., when they choose to join the system or not by weighing up the waiting cost against any reward or compensation), the ISD mechanism still brings the greatest social welfare for both the cooperative and non-cooperative strategies.However, the ISD mechanism performs best in terms of effectiveness only when the ratio of the reward or compensation to the waiting cost is greater than a certain threshold; when the ratio is below this threshold, the ISR mechanism is best. Regarding fairness among SUs, the ISD mechanism performs best when SUs adopt uncooperative joining strategies, but no clear result is found when the SUs follow cooperative strategies. For this scenario, we carry out numerical experiments to show how the optimal mechanism changes as the system parameters vary.

文献来源：Zhang, Y., & Wang, J. (2023). Effectiveness, fairness and social welfare maximization: service rules for the interrupted secondary users in cognitive radio networks. Annals of Operations Research, 323(1-2), 247-286.