The two main goals in wireless networks are to provide channel allocation opportunities for incoming services and to assure the accomplishment of ongoing services. In this paper, a channel reservation scheme in cooperative cognitive radio networks (CRNs) based on dynamic spectrum access (DSA) is proposed. In this scheme, a centralized cognitive manager (CCM) provides the dynamic coordination access for primary users (PUs) and secondary users (SUs) through partitioning the spectrum into non-reserved channels (N-CRN) and reserved channels (R-CRN). N-CRN can be exploited by licensed PUs and unlicensed SUs, while R-CRN is dedicated for active SUs until the successful completion of their service. If a SU session in N-CRN is interrupted by the sudden arrival of PU, then a spectrum handover occurs to R-CRN to resume its session. The reserved channel number $R$ is deduced upon the reduction of both forced termination and blocking probabilities for SUs while satisfying PUs’ traffic demands. Also, overall system cost and SU cost functions are investigated. Simulation results show significant reduction in blocking and forced termination probabilities and improvement in utility function and service completion rate of SUs while meeting PU’s quality of service (QoS) aims. For example, when the arrival traffic rates per channel ${\lambda }_p=0.5$, and for $R=1$,$R=2$ and $R=3$, the values of specific SU forced termination probabilities $P_{\mathit{ft}}$ are 0.1597, 0.116, 0.0799 respectively compared to 0.2106 for the case of no channel reservation. Furthermore, blocking probability and service completion rate of PU are evaluated to demonstrate the effect of channel reservation variation on the system performance.

无线网络的两个主要目标是为传入服务提供信道分配机会并确保正在进行的服务的完成。本文提出了一种基于动态频谱接入（DSA）的协作认知无线电网络（CRN）中的信道预留方案。在此方案中，集中式认知管理器（CCM）通过将频谱划分为非保留信道（N-CRN）和保留信道（R-CRN）为主要用户（PU）和次要用户（SU）提供动态协调访问。许可的PU和未许可的SU可以利用N-CRN，而R-CRN则专门用于活动SU，直到成功完成其服务为止。如果由于PU的突然到达而中断了N-CRN中的SU会话，则频谱切换会发生到R-CRN以恢复其会话。$\mathrm{[R}$可以通过减少SU的强制终止和阻塞概率，同时满足PU的流量需求来推导。此外，还研究了总体系统成本和SU成本函数。仿真结果表明，在满足PU的服务质量（QoS）目标的同时，阻塞和强制终止的概率大大降低，SU的效用功能和服务完成率得到改善。例如，当每个频道的到达流量${\lambda }_p=0.5$和 $\mathrm{[R}=\mathrm{1个}$，$\mathrm{[R}=2$ 和 $\mathrm{[R}=3$，特定SU强制终止概率的值 $P_{\mathit{英尺}}$分别为0.1597、0.116和0.0799，而没有频道预留的情况下分别为0.2106。此外，评估了PU的阻塞概率和服务完成率，以证明信道预留变化对系统性能的影响。