认知无线网络有效容量及功率控制研究
发布时间：2019-06-06 12:14
【摘要】：认知无线网络（Cognitive Radio Network, CRN）允许认知用户（也称作次用户）使用主用户的频谱资源。一般来说，认知无线网络有三种工作模式：重叠模式（UnderlayParadigm），覆盖模型（Overlay Paradigm）和交织模式（Interweave Paradigm）。当采用重叠模式时，从主用户（Primary User）的角度来看，允许次用户（Secondary User）与主用户同时传输数据，只要它对主用户的干扰在主用户容忍的范围之内；而从次用户的角度来看，次用户必须合理地控制它的发射功率，在保证不对主用户产生有害干扰的同时，尽可能得到较高的传输速率。因此动态资源分配（Dynamic ResourceAllocation，DRA）变得至关重要。次用户利用它所获得的信道状态信息（Channel State Information, CSI）动态调整发射功率、传输速率、带宽甚至天线波束等参数来获得最好的性能，同时保证主链路的服务质量。 近些年随着无线网络的飞速发展及提供的业务不断多样化，例如基于Internet协议的语言、视频等无线业务不断增加。这些业务对网络传输时延都非常敏感，需要满足一定的时延服务质量（Quality of Service, QoS）。因此满足不同业务时延QoS需求成为目前无线网络研究的热点。尤其是认知无线网络，由于频谱共享及干扰功率约束，满足不同时延QoS需求更具有挑战性。因此在认知网络中研究具有时延约束的功率控制策略具有重要意义。 本论文基于有效容量模型，，研究了认知无线网络基于时延约束的功率控制策略，深入分析了不同衰落环境下优化参数（有效容量或干扰功率）与时延约束之间的关系。提出了利用分集接收在保证次用户时延约束的同时提高认知无线系统的容量性能；利用OFDM多子载波传输减小次用户对主用户产生的干扰。主要研究工作内容如下： (一)首先研究了单天线认知无线系统具有时延QoS约束的最优功率控制策略。提出的功率控制策略以最大化认知无线系统有效容量为目标，受限于平均干扰温度门限。推导出时延约束最严格和最宽松两种极限情况下功率控制表达式，以及最优功率控制下Nakagami衰落信道的有效容量闭合解。研究了非对称衰落信道（包括不同的衰落类型及信道增益）不同时延约束条件下认知无线系统的容量性能。结果表明当时延约束较宽松时，干扰信道（次用户发射端与主用户接收端之间）特性对认知系统容量性能起决定性作用；当时延约束较严格时，干扰信道特性对认知无线系统容量性能的影响逐步减小，而认知信道（次用户发射端与次用户接收端之间）特性对认知无线系统容量将起决定性作用。在上述研究的基础上，将主用户数从一个扩展到n个，研究了认知无线系统满足不同时延QoS需求时系统容量与n之间的关系。结果表明当时延约束较宽松时，有效容量随n的增加而降低；而当时延约束变得越来越严格，这种影响逐渐减小。 其次研究了多天线认知无线系统配置多个分集支路，有效容量与时延约束之间的关系。其中次用户接收端采用最大比合并（Maximum Ratio Combining, MRC）接收。结果表明增加天线分集支路可以提高认知信道的容量性能。特别是当时延约束较严格时，有效容量增益得到显著提高。因此多天线配置更适合于时延敏感业务。 (二)首先研究了单载波认知无线系统具有时延QoS约束的最优功率控制策略。提出的功率控制策略在保证到达业务流所需时延QoS约束的同时，最小化主用户接收端平均干扰功率。推导出Nakagami衰落环境下平均干扰功率的闭合解。分析了不同衰落条件下时延约束与干扰功率之间的关系。结果表明时延约束与干扰功率之间存在固有的折中。当次用户的时延约束要求越严格，它对主用户产生的干扰越大。尤其是当认知信道处于深衰落时，干扰功率随时延约束指数θ的增大而急剧增加；而当认知信道质量较好时，干扰功率随时延约束指数θ的增大而增加的速率明显放缓。 其次研究了OFDM多载波认知无线系统具有时延QoS约束的最优功率分配方案。提出的功率分配方案在保证次用户时延QoS约束的同时，最小化所分配子信道总的平均干扰功率之和。从频域角度分析，此功率分配策略按照认知子信道与干扰子信道功率之比从大到小的顺序以注水方式分配功率。而从时域角度分析，此策略又依赖于时延QoS约束指数。分析了不同子信道数情况下干扰功率与时延约束之间的关系。结果表明当时延约束要求较严格时，可以通过增加子信道数目来降低次用户对主用户的干扰。因此在满足干扰温度门限的前提下，基于多载波CR的功率分配比基于单载波CR的功率控制允许时延要求更严格的次用户接入主用户网络。 (三)研究了非理想信道状态信息（Imperfect CSI）认知无线系统有效容量性能。其中次用户接收端部署MRC分集，利用最小均方误差准则（Minimum Mean Square Error,MMSE）估计信道误差。得到了非理想CSI基于平均干扰功率约束的功率控制策略及有效容量表达式。结果表明信道估计误差导致认知无线系统容量降低，尤其是时延约束较宽松时影响更大。而增加分集支路不仅可以提高容量增益；同时还可以补偿信道估计误差导致的容量损失。 分析了非理想CSI基于干扰中断约束的有效容量增益。得到了满足最严苛干扰中断约束条件下的功率控制策略及对应的有效容量下界表达式。分析了有效容量与干扰中断门限、估计误差之间的关系。结果表明基于干扰中断约束与严格峰值干扰功率约束相比，即使很小的干扰中断都可以带来较大的容量增益。特别是时延约束较宽松时，容量增益更显著。另外对于非理想CSI，只要允许一定程度的干扰中断，基于峰值干扰中断约束与基于平均干扰功率约束所得到的容量性能差别不大。
[Abstract]:A cognitive radio network (CRN) allows a cognitive user, also known as a secondary user, to use the spectrum resources of the primary user. In general, the cognitive radio network has three modes of operation: the Underlay Paradigm, the Overlay Paradigm, and the Internetwork Paradigm. when the overlay mode is used, the secondary user is allowed to transmit data at the same time as the primary user, as long as it is within the range of the primary user tolerance, as long as it is within the range of the primary user's tolerance; and from the secondary user's perspective, The secondary user must reasonably control its transmit power to obtain a higher transmission rate as much as possible while ensuring that harmful interference is not generated for the primary user. Dynamic resource allocation (DRA) is therefore critical. The secondary user dynamically adjusts the transmission power, the transmission rate, the bandwidth, and even the antenna beam to obtain the best performance by using the channel state information (CSI) obtained by the secondary user, and at the same time, the service quality of the main link is ensured. In recent years, with the rapid development of the wireless network and the continuous diversification of the services, such as the Internet protocol-based language, video and other wireless services Add. These services are very sensitive to network transmission time delay and need to meet certain time-delay quality of service (QoS) therefore, meeting the QoS requirement of different service time delay becomes the heat of the current wireless network research Point. In particular, cognitive wireless networks, which are more challenging to meet different time-delay QoS requirements due to spectrum sharing and interference power constraints Therefore, it is important to study the power control strategy with time delay constraint in the cognitive network In this paper, based on the effective capacity model, the power control strategy based on time delay constraint of cognitive radio network is studied, and the optimization parameters (effective capacity or interference power) and time delay constraint in different fading environments are analyzed. According to the invention, the capacity performance of the cognitive radio system is improved while the time delay of the secondary user is guaranteed by the diversity reception, and the generation of the primary user by the secondary user is reduced by using the OFDM multi-subcarrier transmission, The main research work The results are as follows: (1) The optimal work of the single-antenna cognitive radio system with time-delay QoS constraint is first studied. Rate control strategy. The proposed power control strategy is to maximize the effective capacity of the cognitive radio system and is limited to the average dry In this paper, the power control expression and the effective control of the Nakagami fading channel under the optimal power control are derived. The paper studies the cognitive radio system under different time delay with different fading channels (including different fading types and channel gains). The results show that the characteristics of the interference channel (the secondary user transmitting end and the receiving end of the main user) play a decisive role in the capacity performance of the cognitive system when the delay constraint is more relaxed; when the delay constraint is more strict, the effect of the interference channel characteristics on the capacity performance of the cognitive radio system in response to step-by-step reduction, that characteristic of the cognitive channel (between the secondary-user-transmitting end and the secondary-user-receiving end) will play a role in the capacity of the cognitive radio system, On the basis of the above-mentioned research, the main number of users is extended from one to n, and the system capacity and n when the cognitive radio system meets the requirements of different time-delay QoS is studied. The results show that the effective capacity decreases with the increase of n when the time-delay constraint is looser, and the time-delay constraint becomes more and more strict, In addition, that multi-diversity branch, the effective capacity and the time delay of the multi-antenna cognitive radio system are studied. The relationship between the constraints. Maximum Ratio combining is used for the secondary user receiving end The results show that the increase of the antenna diversity branch can improve the cognition. The capacity performance of the channel. In particular, when the delay constraint is more strict, the effective capacity is increased. the benefits are significantly improved, so the multi-antenna configuration is more suitable In this paper, the time-delay QoS constraint of the single-carrier cognitive radio system is studied firstly. the proposed power control strategy minimizes the primary user while ensuring the time delay qos constraints required to reach the traffic flow, The average interference power of the receiving end is derived. The lower level of the Nakagami fading environment is derived. The closed solution of the average interference power is analyzed. The time-delay constraints under different fading conditions are analyzed. The relationship between the interference power and the interference power. The results show that the time delay and the interference power there is an inherent trade-off. the more stringent the time delay constraint requirements of the secondary user, it will the larger the interference power generated by the user, especially when the cognitive channel is in deep fading, the interference power is greatly increased by the increase of the constraint index value at any time; and when the quality of the cognitive channel is good, the interference power can delay the increase of the constraint index value at any time, In this paper, the time-delay QoS of the OFDM multi-carrier cognitive radio system is studied. the proposed power distribution scheme minimizes the allocated sub-mail while ensuring the secondary user's time-delay qos constraints, The sum of the total average interference power of the channel. From the frequency domain angle analysis, the power distribution strategy is from large to small according to the ratio of the cognitive sub-channel to the interference sub-channel power The power is assigned in a water-injection manner. From the time-domain angle analysis, this policy is based on The time delay QoS constraint index is analyzed. The interference work in the case of different sub-channel numbers is analyzed. The relationship between the rate and the delay constraint. The results show that the number of sub-channels can be reduced by increasing the number of sub-channels when the time-delay constraint is more stringent. and therefore, the power distribution based on the multi-carrier CR is more strict than that of the single-carrier CR based on the power control of the single-carrier CR, The secondary user accesses the primary user network. (3) the non-ideal channel state information (Imperuse CSI) is studied ) The effective capacity performance of the cognitive radio system. The secondary user receives the MRC diversity at the receiving end and uses the minimum mean square error criterion (Minimum Mean Square Erro). R, MMSE) estimation of channel error. The work of non-ideal CSI based on average interference power constraint is obtained. The results show that the channel estimation error leads to a decrease in the capacity of the cognitive radio system, especially In addition, that increase of the diversity branch not only can improve the capacity gain, but also can also be compensated. Capacity loss due to channel estimation error. Non-ideal CSI is analyzed The effective capacity gain based on the interference interruption constraint is obtained. The power control under the most severe interference interruption constraints is obtained. The lower bound expression of the strategy and the corresponding effective capacity. The effective capacity and the dry capacity are analyzed. The relationship between the interference interrupt threshold and the estimated error is estimated. The results show that the interference-based interrupt constraint is very small compared with the strict peak-interference power constraint. a disturbance can result in a larger capacity gain, in particular, The capacity gain is more significant when the delay constraint is more relaxed. In addition, for non-ideal CSI, only a certain degree of interference interruption is allowed, and based on the peak interference interruption constraint and the average interference power,
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN92
本文编号：2494358
[Abstract]:A cognitive radio network (CRN) allows a cognitive user, also known as a secondary user, to use the spectrum resources of the primary user. In general, the cognitive radio network has three modes of operation: the Underlay Paradigm, the Overlay Paradigm, and the Internetwork Paradigm. when the overlay mode is used, the secondary user is allowed to transmit data at the same time as the primary user, as long as it is within the range of the primary user tolerance, as long as it is within the range of the primary user's tolerance; and from the secondary user's perspective, The secondary user must reasonably control its transmit power to obtain a higher transmission rate as much as possible while ensuring that harmful interference is not generated for the primary user. Dynamic resource allocation (DRA) is therefore critical. The secondary user dynamically adjusts the transmission power, the transmission rate, the bandwidth, and even the antenna beam to obtain the best performance by using the channel state information (CSI) obtained by the secondary user, and at the same time, the service quality of the main link is ensured. In recent years, with the rapid development of the wireless network and the continuous diversification of the services, such as the Internet protocol-based language, video and other wireless services Add. These services are very sensitive to network transmission time delay and need to meet certain time-delay quality of service (QoS) therefore, meeting the QoS requirement of different service time delay becomes the heat of the current wireless network research Point. In particular, cognitive wireless networks, which are more challenging to meet different time-delay QoS requirements due to spectrum sharing and interference power constraints Therefore, it is important to study the power control strategy with time delay constraint in the cognitive network In this paper, based on the effective capacity model, the power control strategy based on time delay constraint of cognitive radio network is studied, and the optimization parameters (effective capacity or interference power) and time delay constraint in different fading environments are analyzed. According to the invention, the capacity performance of the cognitive radio system is improved while the time delay of the secondary user is guaranteed by the diversity reception, and the generation of the primary user by the secondary user is reduced by using the OFDM multi-subcarrier transmission, The main research work The results are as follows: (1) The optimal work of the single-antenna cognitive radio system with time-delay QoS constraint is first studied. Rate control strategy. The proposed power control strategy is to maximize the effective capacity of the cognitive radio system and is limited to the average dry In this paper, the power control expression and the effective control of the Nakagami fading channel under the optimal power control are derived. The paper studies the cognitive radio system under different time delay with different fading channels (including different fading types and channel gains). The results show that the characteristics of the interference channel (the secondary user transmitting end and the receiving end of the main user) play a decisive role in the capacity performance of the cognitive system when the delay constraint is more relaxed; when the delay constraint is more strict, the effect of the interference channel characteristics on the capacity performance of the cognitive radio system in response to step-by-step reduction, that characteristic of the cognitive channel (between the secondary-user-transmitting end and the secondary-user-receiving end) will play a role in the capacity of the cognitive radio system, On the basis of the above-mentioned research, the main number of users is extended from one to n, and the system capacity and n when the cognitive radio system meets the requirements of different time-delay QoS is studied. The results show that the effective capacity decreases with the increase of n when the time-delay constraint is looser, and the time-delay constraint becomes more and more strict, In addition, that multi-diversity branch, the effective capacity and the time delay of the multi-antenna cognitive radio system are studied. The relationship between the constraints. Maximum Ratio combining is used for the secondary user receiving end The results show that the increase of the antenna diversity branch can improve the cognition. The capacity performance of the channel. In particular, when the delay constraint is more strict, the effective capacity is increased. the benefits are significantly improved, so the multi-antenna configuration is more suitable In this paper, the time-delay QoS constraint of the single-carrier cognitive radio system is studied firstly. the proposed power control strategy minimizes the primary user while ensuring the time delay qos constraints required to reach the traffic flow, The average interference power of the receiving end is derived. The lower level of the Nakagami fading environment is derived. The closed solution of the average interference power is analyzed. The time-delay constraints under different fading conditions are analyzed. The relationship between the interference power and the interference power. The results show that the time delay and the interference power there is an inherent trade-off. the more stringent the time delay constraint requirements of the secondary user, it will the larger the interference power generated by the user, especially when the cognitive channel is in deep fading, the interference power is greatly increased by the increase of the constraint index value at any time; and when the quality of the cognitive channel is good, the interference power can delay the increase of the constraint index value at any time, In this paper, the time-delay QoS of the OFDM multi-carrier cognitive radio system is studied. the proposed power distribution scheme minimizes the allocated sub-mail while ensuring the secondary user's time-delay qos constraints, The sum of the total average interference power of the channel. From the frequency domain angle analysis, the power distribution strategy is from large to small according to the ratio of the cognitive sub-channel to the interference sub-channel power The power is assigned in a water-injection manner. From the time-domain angle analysis, this policy is based on The time delay QoS constraint index is analyzed. The interference work in the case of different sub-channel numbers is analyzed. The relationship between the rate and the delay constraint. The results show that the number of sub-channels can be reduced by increasing the number of sub-channels when the time-delay constraint is more stringent. and therefore, the power distribution based on the multi-carrier CR is more strict than that of the single-carrier CR based on the power control of the single-carrier CR, The secondary user accesses the primary user network. (3) the non-ideal channel state information (Imperuse CSI) is studied ) The effective capacity performance of the cognitive radio system. The secondary user receives the MRC diversity at the receiving end and uses the minimum mean square error criterion (Minimum Mean Square Erro). R, MMSE) estimation of channel error. The work of non-ideal CSI based on average interference power constraint is obtained. The results show that the channel estimation error leads to a decrease in the capacity of the cognitive radio system, especially In addition, that increase of the diversity branch not only can improve the capacity gain, but also can also be compensated. Capacity loss due to channel estimation error. Non-ideal CSI is analyzed The effective capacity gain based on the interference interruption constraint is obtained. The power control under the most severe interference interruption constraints is obtained. The lower bound expression of the strategy and the corresponding effective capacity. The effective capacity and the dry capacity are analyzed. The relationship between the interference interrupt threshold and the estimated error is estimated. The results show that the interference-based interrupt constraint is very small compared with the strict peak-interference power constraint. a disturbance can result in a larger capacity gain, in particular, The capacity gain is more significant when the delay constraint is more relaxed. In addition, for non-ideal CSI, only a certain degree of interference interruption is allowed, and based on the peak interference interruption constraint and the average interference power,
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN92
【参考文献】
相关期刊论文 前4条
1 刘爽;朱凯;董宸;;基于PLC一维极轴自动控制的对日跟踪系统[J];工业控制计算机;2010年01期
2 XU Ding;FENG ZhiYong;ZHANG Ping;;Effective capacity of delay quality-of-service constrained spectrum sharing cognitive radio with outdated channel feedback[J];Science China(Information Sciences);2013年06期
3 魏急波;王杉;赵海涛;;认知无线网络:关键技术与研究现状[J];通信学报;2011年11期
4 徐勇军;赵晓晖;;基于QoS和干扰温度约束的多用户认知无线电网络最优功率分配(英文)[J];中国通信;2013年10期
本文编号：2494358
本文链接：https://www.wllwen.com/kejilunwen/wltx/2494358.html
