认知无线电系统中联合频谱分配算法研究

发布时间：2018-05-24 10:49

本文选题：认知无线电 + 频谱分配　；参考：《哈尔滨工业大学》2016年博士论文

【摘要】：随着无线通信技术的快速发展和无线用户数量的逐渐增长,用户对频谱的需要量越来越大,频谱资源紧张成为目前无线电管理中一个严峻的问题。目前,认知无线电静态频谱分配技术缺乏灵活性,导致频谱利用率低、引发频谱浪费。动态频谱分配技术是在保证授权用户正常通信的前提下,分析周围无线环境,对空闲频谱进行二次利用,从而更加有效地使用有限的频谱资源,缓解了无线通信需求与频谱资源之间的矛盾。因此动态频谱分配技术在无线通信领域有非常广阔的应用前景,已成为认知无线电系统中研究热点。本文主要以图论和博弈相关理论为基础,利用最优化方法研究认知无线电中频谱分配问题,具体研究内容如下:本文分别对认知无线电中图论和博弈论的频谱分配算法进行了详细的分析和研究,充分考虑了系统公平、瓶颈认知用户效用和用户间的决策干扰对联合频谱分配性能的影响。本文主要围绕联合分配算法步骤、分配性能的分析和仿真来展开。此外,为了降低认知用户彼此的竞争和减少对授权用户的影响,本文还用可靠性理论描述一个信道是否能够被认知用户所使用以及被连续使用一段时间的概率,进而提出空域、时域和频域三维联合频谱分配算法,从时域、频域和空域进行分析。本文在图论和博弈论相关理论的基础上,提出了四种频谱分配算法,并分析了算法的有效性。本文提出的具体四个创新点分别是:在图论的基础上,针对目前仅适用协作式最大化最小带宽标准的并行算法,存在的认知用户公平性低,瓶颈用户效用不高的问题,本文提出了纵向联合并行的频谱分配算法。计算子图标号时采用协作式最大化最小带宽和协作式最大化比例公平两种不同的标准,分析了不同的比例因子对系统公平的影响。根据最佳的比例因子取值,部分信道运用协作式最大化最小带宽标准分配,在分配这些信道的同时,再对剩余的信道运用协作式最大化比例公平标准进行分配,并计算各个认知用户使用频谱的标号。仿真结果表明纵向联合并行算法的系统公平比已有的并行算法有了明显的改善,瓶颈认知用户信道容量也得到了较大程度的提高。纵向联合并行算法兼顾了系统公平和瓶颈认知用户效用的同时,又有效控制了通信开销。在博弈论的基础上,本文提出了新的非合作博弈的频谱分配算法,克服了用户间决策的干扰影响。在实际的认知无线电通信中,多用户需要共享频谱,认知用户之间不进行相互协作。本文提出新的非合作博弈的频谱分配算法,研究了多个认知用户彼此方案关系,最大化自身的吞吐量。仿真结果表明,新的非合作博弈的频谱分配可以使认知用户和授权用户共享信道,在满足干扰功率约束条件下,认知用户之间进行博弈从而实现合理的功率分配。新的非合作博弈的频谱分配算法的稳定认知用户速率大于传统的非合作博弈算法和下垫式共享的算法,仿真验证了本文提出算法的有效性。从实际应用出发,本文提出了基于图论和博弈论的频谱分配算法。其克服了图论算法不符合实际频谱效用的问题,也克服了博弈论算法从频谱共享池中获取频谱的比较困难的问题。本文首先应用图论算法进行快速的预分配频谱,该算法同时为再次分配保证了公平性,然后用博弈论思想优化初次分配的信道,完成认知用户之间的频谱再次分配,基于图论和博弈论的频谱分配算法充分利用了图论和博弈论的优点。仿真结果表明基于博弈论和图论的频谱分配算法可以使频谱资源被充分利用,在传输功率的约束下,每个认知用户优化自身的效用(速率),合理的分配发送功率,基于图论和博弈论的频谱分配算法相比于单一博弈算法,在使用的信道上可以被分配更多的发送功率,同时效用也得到了提高,联合算法的总效用大于单一博弈论算法的总效用,通过仿真验证了基于图论和博弈论的频谱分配算法的有效性。此外,从空域、时域和频域三个方面,本文提出了空域、时域和频域三维联合频谱分配算法。采用可靠性理论描述一个信道是否能够被认知用户所使用及被连续使用一段时间的概率,降低了认知用户彼此的竞争并减少对授权用户的影响,从而保证认知无线电系统正常通信。仿真结果表明,当主用户数固定时,随着认知用户的增加,空域、时域和频域三维联合算法的传输数据量和系统的总吞吐量优于贪婪算法和二维算法,当认知用户数固定时,随着主用户的增加,系统可传输数据量和系统总吞吐量的趋势随着该算法空闲的主用户数量的增多而提高,空域、时域和频域三维联合算法好于二维算法和贪婪算法。有助于减少认知用户对授权用户的干扰,同时也降低认知用户彼此的竞争,且空域、时域和频域三维联合算法的系统总吞吐量明显优于另外两种算法,仿真结果表明所提算法的有效性。
[Abstract]:With the rapid development of wireless communication technology and the increasing number of wireless users, the demand for the spectrum is becoming more and more large. The shortage of spectrum resources has become a serious problem in radio management. At present, the static spectrum allocation technology of cognitive radio is lack of flexibility, which leads to the low spectrum utilization and causes the waste of spectrum. On the premise of guaranteeing the normal communication of authorized users, the spectrum allocation technology analyzes the surrounding wireless environment and uses the free spectrum for two times, thus more effectively uses the limited spectrum resources and alleviates the contradiction between the demand of wireless communication and the spectrum resources. Therefore, the dynamic spectrum allocation technology has a very wide range in the field of wireless communication. The prospect of application has become a hot spot in cognitive radio system. Based on graph theory and game theory, this paper studies the problem of spectrum allocation in cognitive radio. The specific research contents are as follows: This paper analyzes the spectrum allocation algorithm of graph theory and game theory in cognitive radio in detail. In this paper, the effect of system fairness, bottleneck cognitive user utility and decision interference between users on the performance of the joint spectrum allocation is considered. This paper mainly focuses on the analysis and Simulation of the joint allocation algorithm steps and distribution performance. In addition, in order to reduce the competition between the cognitive users and reduce the impact on the authorized users, this paper also introduces the results. The reliability theory is used to describe the probability that a channel can be used by the cognitive users and is used for a period of time. Then the spatial, time-domain and frequency domain combined spectrum allocation algorithms are proposed, which are analyzed from the time domain, frequency domain and space domain. Based on the theory of graph theory and game theory, four kinds of spectrum allocation are proposed in this paper. The effectiveness of the algorithm is analyzed, and the four specific innovation points proposed in this paper are: on the basis of graph theory, in view of the parallel algorithm which only applies the minimum bandwidth standard of cooperative maximization, the existing problem of low cognitive user fairness and poor utility of bottleneck users, this paper proposes a longitudinal joint parallel spectrum allocation calculation. Method. When calculating the sub icon number, two different standards are adopted for the cooperative maximization minimum bandwidth and the cooperative maximization proportional fairness. The effect of the different proportion factors on the system fairness is analyzed. According to the optimal proportion factor, the partial channel is allocated by the cooperative maximum minimum band width standard, while the channels are allocated. Then the remaining channels are allocated by the cooperative maximization proportional fair standard, and the frequency spectrum of each cognitive user is calculated. The simulation results show that the system fairness of the longitudinal joint parallel algorithm has been obviously improved compared with the existing parallel algorithm, and the bottleneck cognition user channel capacity has also been greatly improved. On the basis of game theory, this paper proposes a new spectrum allocation algorithm for non cooperative game on the basis of game theory, and overcomes the interference effect of decision making between users. In actual cognitive radio communication, multi users need to share the spectrum and recognize the spectrum. In this paper, a new spectrum allocation algorithm for non cooperative game is proposed in this paper to study the relationship between multiple cognitive users and maximize their throughput. The simulation results show that the spectrum allocation of the new non cooperative game can enable the cognitive users and the authorized users to share the channel and satisfy the interference power constraints. Under the condition, the cognitive users play a game to achieve a reasonable power allocation. The stable cognitive user rate of the new non cooperative game spectrum allocation algorithm is greater than the traditional non cooperative game algorithm and the underlying sharing algorithm. The simulation proves the effectiveness of the proposed algorithm. The spectrum allocation algorithm of game theory and game theory overcomes the problem that the graph theory does not conform to the actual spectrum utility. It also overcomes the problem that the game theory algorithm is difficult to obtain the spectrum from the spectrum sharing pool. First, the graph theory algorithm is used to make the fast preallocation of the spectrum, and the algorithm guarantees the fairness for the redistribution at the same time, and then the algorithm is used to ensure the fairness of the algorithm. The game theory is used to optimize the channel for the initial distribution, and the spectrum allocation between cognitive users is completed. The spectrum allocation algorithm based on graph theory and game theory makes full use of the advantages of graph theory and game theory. The simulation results show that spectrum allocation algorithm based on game theory and graph theory can make the spectrum resources fully utilized and transmit power. Under the constraint, each cognitive user optimizes its own utility (rate) and distributes the transmission power reasonably. The spectrum allocation algorithm based on graph theory and game theory can be allocated more transmission power than single game algorithm on the channel used, and the utility is also improved. The total utility of the joint algorithm is larger than the single game theory. The effectiveness of the spectrum allocation algorithm based on graph theory and game theory is verified by simulation. In addition, from three aspects of space, time domain and frequency domain, this paper proposes a spatial, time domain and frequency domain three dimensional joint spectrum allocation algorithm. The reliability theory is used to describe whether a channel can be used by the cognitive users and is used continuously. The probability of a period of time reduces the competition between the cognitive users and reduces the impact on the authorized users, thus ensuring the normal communication of the cognitive radio system. The simulation results show that the volume of data and the total throughput of the system are better than that of the cognitive users when the number of users is fixed, with the increase of the cognitive users. The greedy algorithm and the two-dimensional algorithm, when the number of cognitive users is fixed, with the increase of the main user, the system can transmit the amount of data and the total system throughput with the increase of the number of idle main users of the algorithm. Space, time domain and frequency domain three dimensional joint algorithm is better than the two-dimensional algorithm and greedy algorithm. The interference of the users is authorized and the competition between the cognitive users is also reduced, and the total throughput of the spatial domain, the time domain and the frequency domain three dimensional joint algorithm is obviously superior to the other two algorithms. The simulation results show the effectiveness of the proposed algorithm.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN925

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