认知无线电中继传输优化研究

发布时间：2018-05-27 19:20

本文选题：认知无线电 + OFDM　；参考：《浙江工业大学》2016年博士论文

【摘要】：随着无线通信技术进行的研究和技术上的不断创新,无线通信的发展日新月异,无线用户数量逐渐普及。然而,无线通信技术正处于发展之中,仍有许多难题需要解决,其中由于无线通信业务的快速发展,带来的频谱资源趋于饱和的问题,现有的技术存在非常大的局限性。现有研究表明,虽然频谱资源饱和,但是,对已有的频谱利用并不充分。如何解决频谱资源紧张,同时利用网络节点来增强网络性能,引起国内外很多学者的关注和研究。而认知无线电的理论和技术被认为是解决这一问题的很有前途的技术。认知无线电主要是一个智能的无线通信技术,具备三个方面的能力:首先能够检测到授权和非授权的空闲频谱资源;然后能够接入空闲频谱;还要能够依据其所在无线网络环境的变化自己调整天线的各项参数,从而达到通信的目的。这项技术通过提高频谱的利用率来解决频谱资源紧张的难题。同时协作中继技术,可以对抗无线传输中信道传输衰落的影响,是增强无线系统传输范围和提高QoS(Quality of Service)的重要技术。本文以认知无线电作为背景,结合中继协作技术,研究了如何解决如何在不影响主用户(Primary User,PU)传输的情况下,使次级用户(Secondary User,SU)不仅能够利用多余的网络资源传输自己的数据,还能帮助主用户提高系统传输性能,提高无线网络中资源的利用率。本文的主要工作和贡献如下:第一,针对普通双跳认知中继网络中存在的中继距离不够,无法进行双向通信的问题,提出了一种新的三跳中继模型,可以充分利用认知节点的通信对,来组成三跳网络,提高了传输距离,同时实现了认知用户之间的双向通信。第二,针对越来越多的使用电池的无线设备出现的能效优化问题,提出了通过网络编码双向中继减少资源消耗,并利用节点间传输的代偿来平均电池的能量消耗,从而提高系统的总传输数据量。第三,以OFDM为载体,研究基于合作的正交式频谱共享模型下认知用户功率分配。根据OFDM的特点,分析认知用户与授权用户相互之间的干扰并建立干扰模型,通过启发式的子载波匹配方式来对能效进行优化。第四,针对无线网络中使用电池的节点经常出现“浪费”状态或者“饿死”状态,提出了将网络中节点的能量传输分为时间维度和节点维度建立传输模型,并通过拉格朗日法求最优解,来提高节点的能量利用率和节点的总吞吐量。
[Abstract]:With the research and innovation of wireless communication technology, the development of wireless communication is changing with each passing day, and the number of wireless users is becoming more and more popular. However, with the development of wireless communication technology, there are still many difficult problems to be solved. Due to the rapid development of wireless communication services, the spectrum resources tend to saturation, and the existing technology has great limitations. Existing studies show that, although the spectrum resources are saturated, the existing spectrum is not fully utilized. How to solve the shortage of spectrum resources and make use of network nodes to enhance network performance has attracted the attention and research of many scholars at home and abroad. The theory and technology of cognitive radio is considered to be a promising technology to solve this problem. Cognitive radio is an intelligent wireless communication technology, which has three capabilities: first, it can detect the free spectrum resource, then it can access the free spectrum. It also can adjust the antenna parameters according to the change of the wireless network environment, so as to achieve the purpose of communication. This technique solves the problem of the shortage of spectrum resources by improving the efficiency of spectrum. At the same time, cooperative relay technology, which can resist the influence of channel fading in wireless transmission, is an important technology to enhance the transmission range of wireless system and improve the QoS(Quality of Service. Based on cognitive radio and relay cooperation technology, this paper studies how to solve the problem of how to make secondary user can not only use redundant network resources to transmit their own data without affecting primary user PUU transmission, but also the secondary user can use redundant network resources to transmit their own data. It can also help the primary user to improve the transmission performance of the system and improve the utilization of resources in the wireless network. The main work and contributions of this paper are as follows: first, a new three-hop relay model is proposed to solve the problem that the relay distance is not enough in the general two-hop cognitive relay network. It can make full use of the communication pairs of cognitive nodes to form a three-hop network, improve the transmission distance, and realize the two-way communication between cognitive users at the same time. Secondly, aiming at the problem of energy efficiency optimization in more and more wireless devices using battery, the paper proposes to reduce resource consumption by network coded bidirectional relay, and to use the compensation of transmission between nodes to average battery energy consumption. In order to improve the total data transmission system. Thirdly, using OFDM as the carrier, the power allocation of cognitive users based on cooperative orthogonal spectrum sharing model is studied. According to the characteristics of OFDM, the interference between cognitive users and authorized users is analyzed, and the interference model is established, and the energy efficiency is optimized by heuristic subcarrier matching. Fourthly, aiming at the status of "waste" or "starvation" of nodes using batteries in wireless networks, a transmission model is proposed to divide the energy transmission of nodes into time dimension and node dimension. In order to improve the energy utilization rate and the total throughput of the nodes, the Lagrange method is used to find the optimal solution.
【学位授予单位】：浙江工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN925

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