基于信号能量分布的蜂窝和D2D用户资源共享技术研究

发布时间：2018-06-20 17:55

本文选题：端到端通信 + 资源共享　；参考：《哈尔滨工业大学》2017年博士论文

【摘要】：随着无线移动通信用户数的增多以及通信数据量的增大,蜂窝系统的集中式控制模式逐渐显露一些弊端。与之相比,D2D(Device-to-Device)通信的短距离通信特性可弥补蜂窝集中式控制模式的不足,提供更多优势,可降低发射功率,节约能耗;可缩短传输所用时间,减小延时。特别是,D2D的空间复用特性通过空间复用和合理的资源分配,使D2D用户可以和蜂窝用户使用同一资源同时传输信息,进行资源共享,提高系统的总容量及单位功率容量。但采用非正交资源共享方式进行通信时,蜂窝用户和D2D用户间会产生新的干扰,若不对互干扰进行处理,将严重影响蜂窝用户和D2D用户的通信性能。基于以上原因,在蜂窝和D2D用户共存的网络中,需要对共享资源的蜂窝和D2D用户间的干扰以及不同D2D用户对间的干扰进行抑制。传统的资源共享技术主要是通过资源分配、距离限制和功率控制,在保证蜂窝系统最小通信质量需求的前提下,使D2D用户和速率最大化。但这三种技术都是在D2D链路和蜂窝链路采用完全相同的载波资源进行通信的基础上展开的,如果通过增加复用距离来抑制干扰,会导致蜂窝和D2D用户间可复用用户数减少;如果通过控制用户功率来降低干扰,降低对彼此干扰的同时也会使自身信干噪比下降。本文的立足点是在蜂窝和D2D用户复用距离不变、用户功率不变的前提下,对信号进行功率谱及时变谱分析,根据蜂窝和D2D信号在频域及时频平面的能量分布特性,将彼此高能量区在时频平面上交错分配,那么在接收端通过滤波可同时提升蜂窝用户和D2D用户的信干噪比。首先,针对单载波脉冲成型频分复用信号在频域的能量分布特性,提出了基于保护带的蜂窝和D2D用户上行资源共享技术,并从理论上给出了该技术的机理优势。所提资源共享方法将蜂窝和D2D用户的载波中心布置在彼此频域上的低能量区域,通过接收端的带通滤波,可抑制彼此间干扰。本文推导了平坦衰落信道条件下采用该技术的D2D用户条件中断概率的闭合表达式,以及频选信道下采用所提资源共享技术的D2D用户条件中断概率的数值计算表达式。对所提方法和传统基于距离限制的资源共享方法在平坦衰落信道下进行仿真,验证了所提方法在D2D用户中断概率性能上的优越性及理论推导的正确性。同时,还讨论了在频选信道下所提方法的使用条件,以及噪声较小或较大时所提方法在性能提升方面的局限性。多载波脉冲成型的机理以及多载波系统的资源分配方法都和单载波不同。本文针对多载波脉冲成型信号在保护带内时频资源块上的低能量特性,提出了一种多载波系统下行资源共享技术。所提多载波下行链路资源共享方法在为D2D用户分配资源块时优先考虑保护带内的可用资源块,然后再考虑非保护带内被蜂窝用户使用的资源块。D2D用户使用保护带内资源时,与蜂窝用户间的干扰可得到有效抑制。在平坦衰落信道下,所提资源共享方法对保护带内资源和非保护带内资源进行分段功率优化,仿真结果表明所提方法可有效提升D2D用户和速率及谱效率。在频选信道下,本文将系统和速率转化到频域进行分析,根据各子信道的信道状态进行优化资源分配,并采用注水定理实现最优信道配置,仿真结果表明,在频选信道下所提方法可在保证蜂窝系统通信质量的情况下有效提升D2D用户的和速率。最后,根据脉冲成型4QAM(Quadrature Amplitude Modulation)信号I/Q两路分离后表现出的时频域能量变化特性,提出了基于时频分析及时变滤波的资源共享方法。针对信号的能量分布特性进行时变滤波,实现蜂窝用户和D2D用户信干噪比的同时提升。本文通过分析4QAM调制信号I/Q两路分离后的时频分布特点,以及窗长度对时频分辨率和射频基带等效性的影响,阐明了所提资源共享方法的优势。然后针对I/Q两路分离后的4QAM信号的时变能量特性,设计有效滤波通域,以最优BER(Bit Error Rate)优化准则得到最优门限值,最终设计并实现了基于门限限制的时变滤波方法。从D2D接收端滤波后信干噪比和误码性能两个方面对所提基于时频分析的资源共享方法进行了评价,所得结果证实了所提方法相比现有采用低通/带通滤波方法的性能优势。
[Abstract]:With the increase of the number of wireless mobile communication users and the increase of the amount of communication data, the centralized control mode of the cellular system gradually shows some disadvantages. Compared with this, the short distance communication characteristics of D2D (Device-to-Device) communication can make up the deficiency of the cellular centralized control mode, and provide more advantages, which can reduce the transmission power and save energy. It can shorten the time used for transmission and reduce the delay. In particular, the spatial multiplexing characteristics of D2D can make D2D users transmit information with the same resource, share the resources, improve the total capacity of the system and unit power rate by using the same resource with the cellular users, but use the non orthogonal resource sharing mode to carry on the communication. New interference between cellular users and D2D users will be generated in the letter, which will seriously affect the communication performance of cellular users and D2D users. For these reasons, the interference between the cellular and D2D users of shared resources and the interference between different D2D users is required in the coexistence of cellular and D2D users. Inhibition. The traditional resource sharing technology is mainly based on resource allocation, distance restriction and power control to maximize the D2D users and rates on the premise of ensuring the minimum communication quality requirement of the cellular system. However, these three technologies are based on the communication between the D2D link and the cellular link with the same carrier resource. If the multiplex distance is used to suppress interference, the number of reusable users between the honeycomb and D2D users will be reduced. If the interference is reduced by controlling the power of the user and the interference to each other will be reduced, the signal to noise ratio will be reduced. This paper is based on the premise that the reuse distance of the cellular and D2D users is constant and the power of the user is constant. At the same time, the power spectrum of the signal is analyzed in time. According to the energy distribution characteristics of the honeycomb and D2D signal in the frequency domain, the high energy area is interlaced on the time frequency plane, then the signal to noise ratio of the cellular users and the D2D users can be improved at the receiving end simultaneously. First, the frequency division of the single carrier pulse is complex. Using the energy distribution characteristics of the signal in the frequency domain, this paper presents a protection band based honeycomb and D2D user uplink sharing technology, and gives the mechanism advantage of the technology. The proposed resource sharing method assigns the carrier center of the honeycomb and D2D users to the low energy regions in the frequency domain, and can be suppressed through the bandpass filter at the receiver. This paper derives the closed expression of the D2D user condition interruption probability using this technique under the condition of flat fading channel, and the numerical calculation expression of the D2D user condition interrupt probability using the shared resource sharing technology under the frequency selection channel. Simulation in flat fading channel proves the superiority of the proposed method in the performance of D2D users' interruption probability and the correctness of theoretical derivation. At the same time, it also discusses the usage conditions of the proposed method under the frequency selection channel, and the limitation of the proposed method when the noise is smaller or larger. The mechanism of multi carrier pulse shaping is also discussed. And the resource allocation method of multi carrier system is different from that of single carrier. In this paper, a multi carrier system downlink resource sharing technique is proposed for the low energy characteristics of multi carrier pulse shaping signal on the time frequency resource block in the protective band. The multi carrier downlink resource sharing method is given priority for the allocation of resource blocks for D2D users. Considering the available resource blocks in the protective belt, the interference between the cellular users can be effectively suppressed when the resource block.D2D users in the unprotected band are used by the cellular users in the protection band. In flat fading channels, the proposed resource sharing method performs a piecewise power optimization on the resource and unprotected resource in the protected zone. The simulation results show that the proposed method can effectively improve the D2D user and rate and spectral efficiency. In the frequency selective channel, this paper transforms the system and the rate into the frequency domain, optimizes the allocation of resources according to the channel state of each subchannel, and implements the optimal channel configuration using the water injection theorem. The simulation results show that the proposed channel is proposed under the frequency selection channel. The method can effectively improve the D2D user's and rate under the condition of guaranteeing the communication quality of the cellular system. Finally, a resource sharing method based on time frequency analysis and time-varying filtering is proposed based on the time frequency analysis, based on the pulse forming 4QAM (Quadrature Amplitude Modulation) signal I/Q separation. The distribution characteristic is time-varying filtering to achieve the simultaneous enhancement of the signal to noise ratio of the cellular users and the D2D users. By analyzing the time frequency distribution characteristics of the 4QAM modulated signal I/Q, and the influence of the window length on the time-frequency resolution and the equivalence of the radio frequency baseband, the advantages of the proposed source sharing method are clarified. Then, the I/Q two routes are divided. The time-varying energy characteristic of the 4QAM signal is designed and the optimal threshold is obtained by the optimal BER (Bit Error Rate) optimization criterion. Finally, a time-varying filtering method based on the threshold restriction is designed and implemented. The resource sharing based on the time frequency analysis is proposed from two aspects of the signal to noise ratio and the error code performance of the D2D receiver after filtering. The method is evaluated, and the results confirm the performance advantages of the proposed method compared with the existing low pass / bandpass filtering methods.
【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】：2017
【分类号】：TN929.5

【参考文献】