【作者】 梁爽；

【导师】 杨守义；

【作者基本信息】 郑州大学 ， 通信与信息系统， 2016， 硕士

【摘要】 近年来,随着无线通信的快速发展,人们对高速率无线业务的需求越来越高。因此无线频谱资源日益短缺,能源消耗也越来越大。认知无线电技术能够很好地解决频谱利用率低的问题。在认知无线电网络中,次用户能够很好地感知周围环境并改变工作参数,从而自适应地接入频谱。同时协作通信技术的出现满足了用户对高速率业务的需求,它通过协作分集技术提高了系统的容量。未来的无线通信不仅要考虑频谱资源利用率低的问题,还要强调能量效率的绿色无线电。鉴于此,本文针对认知无线电中的频谱效率以及能量效率做了相关研究,具体内容包括:1、针对认知无线电网络,研究了基于OFDM非完美频谱感知下能量效率的资源分配。为了不将功率浪费在错误检测,通过定义一个速率损失函数引入了一个新的能效模型,优化该能效的表达式可以节省宝贵的资源,例如电池寿命等,使该能效比传统能效的增益大。在优化中对所有的子信道都进行功率约束,有两种对主用户的干扰容限:峰值干扰功率约束以及平均干扰功率约束,通过比较两种功率约束来衡量能效的性能。经过计算验证了能效和传输功率是拟凹的关系,提出了一种优化的能效资源分配算法。仿真结果表明,新的算法比传统的算法提高了能效,并且在一定的干扰功率下,基于平均干扰功率约束的能效比基于峰值干扰功率约束的能效大。2、针对认知无线电中的双向中继网络,研究了基于OFDM非完美频谱感知下频谱效率的资源分配问题。考虑了两种接入机制:机会式的频谱接入以及共享式的频谱接入。与传统的基于认知的双向中继资源分配方法不同的是,所提的算法联合优化感知时间和发射功率,从而最大化次级系统的吞吐量。在频谱感知阶段,次级系统的两个用户和中继用户联合感知主用户的存在状态,确保了感知结果的准确性。在数据传输阶段,为了有效地保护主用户,每个阶段都考虑平均干扰功率约束以及次级系统总的功率约束,在这些约束条件下,求得最优的感知时间和功率分配。最后仿真比较了两种接入机制的性能,验证了所提算法的有效性。更多还原

【Abstract】 In recent years, with the rapid development of wireless communication, the demand for high speed wireless services is becoming higher. Therefore, the wireless spectrum resources become increasingly scarce, and the energy consumption is also increasing. Cognitive radio technology can well solve the problem of low utilization of spectrum. In cognitive radio networks, the secondary user is able to perceive the environment and change the working parameters, then adaptive access the spectrum.At the same time, the emergence of cooperative communication technology meets the needs of users for high speed business. It improves the capacity of the system through cooperative diversity technology. The future of wireless communication is not only to consider the problem of low utilization of spectrum resources, but also to emphasize energy efficiency of the green radio. In view of this, this paper has done research on the spectrum efficiency and energy efficiency in cognitive radio, the specific contents include:1、According to the cognitive radio network, the resource allocation of energy efficiency based on OFDM imperfect spectrum sensing is studied. In order not to waste power in error detection, by defining a rate loss function introduced a new energy efficiency model, expressions for the efficiency optimization can save valuable resources, such as battery life, the efficiency is larger than that of the traditional energy efficiency gain. In the optimization, all the sub channels are considered power constraint. There are two interference constraints for primary user:peak interference power constraint and the average interference power constraint, by comparing the two power constraint can measure the efficiency of performance. After calculation, verified the efficiency and the transmission power have a quasi concave relationship, and then proposes a resource allocation algorithm for energy efficiency optimization. The simulation results show that the new algorithm for energy efficiency is larger than the traditional method, and in certain interference power,energy efficiency based on the average interference power constraint is larger than theenergy efficiency based on peak interference power constraint.2 、 Based on the two-way relay network in cognitive radio, the resource allocation problem of spectrum efficiency based on OFDM imperfect spectrum sensing is studied. Two access mechanisms are considered: opportunistic spectrum access and shared spectrum access. Different from the traditional two-way relay resource allocation method based on cognitive, the proposed algorithms jointly optimizes the sensing time and transmit power, so as to maximize the throughput of the secondary system. In the spectrum sensing phase, the two users and relay of the secondary system are aware of the existence of the primary user, which ensures the accuracy of the results. In the stage of data transmission, in order to effectively protect the primary user, each stage are considered average interference power constraint and secondary system total power constraint, under these constraints to obtain the optimal sensing time and power allocation. Finally, the performance of the two access mechanisms is compared and the effectiveness of the proposed algorithm is verified.更多还原