动态频谱分配与频谱共享研究综述

文中针对当前无线频谱政策和无线频谱技术局限所导致的频谱整体利用率低的问题,分析了能有效提高频谱利用率的动态频谱分配和共享技术的研究现状,包括相邻和分片动态频谱分配技术,共存和覆盖式频谱共享技术,感知无线电技术,以及频谱池技术,并讨论了其未来的研究方向,尤其是感知无线电和基于OFDM的频谱池方法.     

动态频谱共享简述

无线电频谱是新一代信息技术的重要载体,频谱共享是解决传统使用方式带来的资源供需矛盾和资源利用率低等重要问题的有效手段,为了对动态频谱共享进行介绍,首先通过解析频谱共享概念,分类阐述频谱共享方式,加深了对频谱共享内涵的理解,之后具体介绍了动态频谱共享技术的发展和两种主流实现技术,最后讨论了推行频谱共享的必要性。     

动态频谱共享研究现状及展望

动态频谱共享作为解决频谱供需矛盾的有效方式之一,在国际上受到了广泛关注.首先,对动态频谱共享的发展情况进行了概述.然后,对国际上动态频谱共享的政策制定、标准化及应用情况等进行了梳理.最后,结合无线电管理现状,分析了实施动态频谱共享在频率管理、台站管理及无线电监测等方面的影响及挑战.     

频谱共享应用中的动态频率规划方案探讨

适应频谱动态变化的频率规划方法是蜂窝移动通信系统实现频谱共享应用的核心问题之一.本文在充分考虑频谱资源时变特性和蜂窝移动通信系统频率复用技术特点的基础上,提出了一种适应频谱动态变化的动态频率规划技术,为未来频谱共享蜂窝无线通信系统的实际大规模网络应用奠定了基础.     

室分系统的动态频谱共享方案

动态频谱共享为运营商在室分系统低频段下实现5G NR覆盖层创造了无限可能,同时,室分系统的动态频谱共享还为运营商免去了频谱重耕或购买新频谱许可证的高昂成本,有助于将LTE用户群平稳过渡到5G,并更快推出独立组网模式.探讨了动态频谱共享的背景、部署以及关键技术方案,主要技术方案有MBSFN子帧方案、LTE打孔方案和NR打...     

星地混合系统的动态频谱共享

下一代通信技术的目标是实现全面移动和智能互联.为了实现这一愿景,需要将卫星和地面等异构网络进行无缝集成,构建星地混合系统.针对星地混合系统用频特点和存在的问题,为了提高频谱使用效率,对适用于星地混合系统的动态频谱共享技术进行了分析讨论,重点分析了频谱数据库、频率和功率分配、波束赋形及跳波束等一些适用于星地混合系统且非常...     

动态频谱接入MAC协议研究

机会频谱接入（OSA,Opportunistic Spectrum Access）允许未授权用户在空间域和时域上共享授权频谱,但仅当授权用户没有占用这些频谱时认知用户才能接入。特别地,频谱环境的动态性使MAC协议设计面临着几个重要的问题,即认知用户需要确定何时以什么方式接入哪一个信道发送／接收数据而不影响主用户的通信。从OSA-MAC设计面临的技术挑战出发,对近年来国内外在该方向的研究成果做了总结和分析,并阐述了OSA-MAC设计亟待解决的问题和今后的研究方向。     

LTE FDD与GSM频谱共享方案

4G网络建设已日趋完善，伴随着大量的4G业务需求，运营商的频率资源显得弥足珍贵，而另一方面GSM网络的用户数及承载的语音量成逐年下降趋势。将宝贵的频谱资源应用到LTE这样的高制式网络来提升频谱效率，但是GSM老终端又很难完全退网，传统的Refarming方案为通过静态分配GSM、LTE频谱资源，势必会造成部分频谱浪费。采用频谱共享方案可将频谱进行动态频谱、静态频谱划分，LTE系统与GSM系统通过共享动态频谱资源的方式实现潮汐式共享，从而一方面保证了GSM网络的语音资源，另一方面也提高了LTE网络的容量，从而整体提高网络的频谱利用效率。     

动态频谱接入MAC协议研究

机会频谱接入（OSA,opportunistic spectrum access）允许未授权用户在空间域和时域上共享授权频谱,但仅当授权用户没有占用这些频谱时认知用户才能接入。另外频谱环境的动态性使MAC协议设计面临着几个重要的问题,即认知用户需要确定何时以什么方式接入哪一个信道发送/接收数据而不影响主用户的通信。从OSA-MAC设计面临的技术挑战出发,对近年来国内外在该方向的研究成果做了总结和分析,并阐述了OSA-MAC设计亟待解决的问题和今后的研究方向。     

TD-LTE系统频谱共享应用的实现方案探讨

频谱共享应用是提高频谱利用率、缓解未来移动通信系统频谱紧张局面的有效手段。本文从工程应用的角度,对TD-LTE系统实现频谱共享的应用方式及若干关键问题进行了研究和探索,研究结果为未来TD-LTE系统的大规模频谱共享应用提供了有益参考。     

认知无线网络中一种新的频谱共享方法

频谱共享是认知无线网络关键技术之一。为消除认知无线网络中频率选择性信道下授权主用户与认知用户间的相互干扰,本文提出了一种新的频谱共享方法。该方法充分利用了无线通信系统中由信道的频率选择性衰落导致的不同用户信道的不相关性,通过求解矩阵方程获得预处理矩阵的通解,并在主用户和认知用户发射端分别进行预处理。从而实现认知系统中主用户与认知用户之间的相互零干扰,并使每个用户都可有效地传输数据。理论推导及系统仿真均表明,新方法可以有效地消除授权主用户与认知用户之间的双向干扰,实现不同用户平等地共享无线频谱资源。新方法可以提高频谱的利用率,一定程度上缓解无线频谱资源在当前及未来无线通信领域日益紧缺的矛盾。而且新方法也同样适用于不同认知用户之间共享频谱。      

基于IP网络的动态部分缓冲共享方案

本文基于IP网络提出了一种分组丢弃控制方案——动态部分缓冲共享.和已有的静态部分缓冲共享方案相比,新方案根据分组丢弃行为对控制阈值进行动态调整,从而对网络流量的变化具有更优的适应性.同时新方案也避免了复杂的阈值设置问题,任意设定的初始阈值都不会影响系统稳态性能.实验结果显示,新方案可以保证稳定的相对丢失率性能,并且在相同的流量条件下比原有方案具有更低的抖动延迟.     

认知无线电中基于SA-MIMO-OFDM的动态频谱共享方案

该文提出一种结合频谱自适应(Spectrum Adaptation,SA)与MIMO-OFDM技术的动态频谱共享方案。该方案基于功率门限模型实现非授权信号的自适应频谱成型,并给出了一种简单的动态功率分配算法以最大化比特率。仿真结果表明,该方案能够克服干扰温度模型的局部干扰问题,使用MIMO技术可进一步提高系统性能,通过动态功率分配算法可降低计算复杂性并提高频谱利用率。     

Distributed Spectrum Sharing Scheme for Multiuser Orthogonal Frequency-Division Multiplexing Cognitive Radio Networks

This paper presents a novel spec- trum sharing design aiming at optimising the performance of a Multiuser Orthogonal Freq- uency-Division Multiplexing （MU-OFDM） Co- gnitive Radio Network （CRN） that consists of multiple secondary Transmitter-Receiver （Tx-Rx） pairs. For most MU-OFDM systems, the Exc- lusive Subchannel Assignment （ESA） is an efficient resource allocation method. Noneth- eless, it is inappropriate for the network consi- dered in this paper, because subchannels shar- ing among secondary Tx-Rx pairs can further improve the system performance. We investi- gate the Weighted Sum Rate （WSR） maximi- zation problem under the Shared Subchannel Assignment （SSA）, where each subchannel is shared by multiple secondary Tx-Rx pairs. With Lagrangian duality technique, we decompose the original resource allocation problem into sev- eral sub-problems on each subchannel and pro- pose a duality-based suhchannel sharing ap- proach. For practical realisation in the cogni- tive systems without central control entity, a distributed duality-based WSR maximization scheme is presented. Simulation results mani- fest that the proposed scheme achieves sig- nificantly better performance than ESA duality scheme.     

Dynamic Spectrum Sharing for OFDMA-Based Multi-hop Cognitive Radio Networks with Priority

In this paper, we propose a resource assignment scheme of a secondary user (SU) for a multi-hop cognitive radio network. In multi-hop networks, since each link has different SNR because of their different distance between stations and multipath fading, the link of the smallest SNR is the bottleneck. For overcoming this problem, it is proposed to give a priority to each link based on the link SNR and to assign the resource blocks (RBs) in ordering of instantaneous SNR on the link. This link priority information is shared among nodes through a control channel. Then, we assign the selected SU RB to each SU node according to the SNR ordering with distributed manner. We confirm the effectiveness of the proposed SU RB assignment by using computer simulation.     

基于跳频的自适应频谱共享方案

 本文针对异种网络之间的频谱共享问题,提出了基于跳频的自适应频谱共享方案.该方案中 ,频谱注册网络负责配置跳频频率表等跳频参数,并且将其在覆盖区域内广播.频谱共享网络中的可重构终端（CR-MTs）使用认知无线电（CR）技术对周围频谱进行监测,通过跳频频谱共享策略实现通信.本文设计了跳频频谱共享的信号发射模型和信令交换机制,提出了不同情况下的干扰避免（IA）策略.最后,对跳频频谱共享方案的性能进行了分析,基于干扰计算模型得到的仿真结果表明该方案具有较好的IA性能.     

4G/5G LNR动态频谱共享技术

为实现多频多制式网络完全融合,加速5G全面部署,面向存量4G频谱,引入LNR动态频谱共享技术,解决新制式快速引入、老制式平滑退网、网络资源按需分配等问题,重点研究LNR动态频谱共享技术的实现原理,对4G/5G增益影响进行分析;总结该特性引入的同频异制式干扰问题,规避同频干扰的方法;在无线网络验证过程中,单站定点用户测试...     

Joint Opportunistic Spectrum Sharing and Dynamic Full Frequency Reuse in OFDMA Cellular Relay Networks

This paper considers the problem of spectrum sharing in orthogonal frequency division multiple access cellular relay networks. Firstly, a novel dynamic full frequency reuse scheme is proposed to improve the spectral efficiency. Different from the conventional full frequency reuse scheme which only allows the base station (BS) reusing the subcarriers in the specific regions, an improved full frequency reuse scheme is proposed to allow the BS reusing all the subcarriers in the whole BS coverage region to exploit additional multiuser diversity gain. In order to dynamically reuse the frequency resource among the BS and relay stations (RSs) to further improve the spectral efficiency, the adaptive subcarrier scheduling is introduced into the improved full frequency reuse scheme to obtain more multi-user diversity gain, which forms the proposed novel dynamic full frequency reuse scheme. Secondly, in order to further increase the system throughput, the opportunistic spectrum sharing scheme is introduced to allow the RSs selectively reusing the subcarriers among each other, which joint with the proposed dynamic full frequency reuse scheme to intelligently allocates the subcarriers originally reused by the BS and a RS to another suitable RS which can best improve the system performance after considering the additional interference. Thirdly, in order to select The optimal reusing combination scheme of BS and RSs to exploit more potential system performance, a heuristic approach based on genetic algorithm is proposed to search the optimal BS and RSs combination to opportunistically share the frequency resource. Simulation results show that the proposed dynamic full frequency reuse scheme can obtain high spectral efficiency, fine fairness and low outage probability compared to the conventional full frequency reuse scheme. Furthermore, the system performance can be improved when considering the opportunistic spectrum sharing among RSs. Finally, after adopting the genetic algorithm, the system performance can be greatly improved by the frequency reusing among the optimal BS and RSs combination.     

A Cell Based Dynamic Spectrum Management Scheme with Interference Mitigation for Cognitive Networks

Future wireless systems are expected to be characterized by the coexistence of different radio access technologies (RATs) resulting in complex heterogeneous wireless environments. In parallel with this, the tremendous demand for spectrum has inspired the requirement of dynamic spectrum management (DSM). This paper aims at designing a cell based dynamic spectrum management (CBDSM) scheme to enhance the spectrum utilization and maximize the profit of operators in wireless heterogeneous networks. The system architecture and the functional modules supporting the CBDSM scheme are designed. As a fundamental issue in spectrum management, the inter-system interference issue is solved in the proposed CBDSM scheme. Furthermore, game theory, which is a potential tool for studying the distributed autonomous resource optimization algorithms, is applied to design a spectrum trading algorithm enabling the heterogeneous wireless networks to dynamically trade spectrum and to share the profit. In the algorithm, we take into account the economic value of the spectrum of wireless systems in order to guarantee the rationality for the spectrum trading. The simulation results show that the proposed CBDSM scheme effectively improves the spectrum utilization and the profit of operators while it reduces the mutual interference between wireless networks to a tolerable level.