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分别在平坦衰落和频率选择性衰落的无线信道模型中建立了基于多用户正交频分复用技术(OFDM)和分布式天线的认知无线电系统中子载波分配模型.该模型不再用“干扰温度”限制认知用户来保护主用户,而是规定主用户在其所有子载波上的吞吐量之和需要高于一定的门限.然后,根据不同信道模型的特点提出了最优子载波分配方案,该方案利用分支定界法和隐枚举法最大化系统的吞吐量.最后,利用Pegging算法提出了效率与公平折中的子载波分配方案.仿真证明,在不同场景中所提出的子载波分配方案与现有方案相比在吞吐量和公平性方面均具有较大的优势.
The subcarrier allocation model in cognitive radio system based on multi-user Orthogonal Frequency Division Multiplexing (OFDM) and distributed antenna is established respectively in the wireless channel model of flat fading and frequency selective fading.The model is no longer used Instead of restricting the cognitive user from protecting the primary user, the interference temperature requires that the sum of the throughput of the primary user over all its subcarriers needs to be above a certain threshold.And then, according to the characteristics of different channel models, Carrier allocation scheme, which uses the branch-and-bound method and implicit enumeration method to maximize the throughput of the system.Finally, the subcarrier allocation scheme with efficiency and fair compromise is proposed by using the Pegging algorithm.The simulation proves that in different scenarios Compared with the existing schemes, the subcarrier allocation scheme has greater advantages in terms of throughput and fairness.