共查询到19条相似文献,搜索用时 125 毫秒
1.
2.
3.
4.
为了提高无线携能通信(SWIPT)的效率,在基站采用3维(3D)定向天线,通过动态调整天线下倾角,来开发垂直维度,从而增强SWIPT中能量和信息的传输效率。该文研究单小区多输入多输出(MIMO)SWIPT系统,基站和用户分别使用迫零(ZF)预编码和功率划分(PS)技术。构建以最小化发送功率为目标的优化问题,在信噪比(SNR)和获取功率的约束下,联合优化了天线下倾角,PS比和分配的功率。最佳PS比和最优功率分配以闭合表达式给出。仿真表明,所得到的优化解的性能优于具有可调下倾角的常规MIMO系统和不考虑垂直维度的2维(2D)方案。 相似文献
5.
乔惠东肖如奇杨国吴文 《微波学报》2023,(1):64-67
应用传统优化馈电幅值相位的方法来设计多波束阵列天线时,计算量与过程比较复杂,采用一些优化算法也往往只能得到局部最优解。而基于最大功率传输效率法(MMPTE)对天线阵列进行优化,可以得到理论上最优的天线单元馈电的幅值和相位。本文首先介绍了最大功率传输效率法,然后设计了微波多波束阵列天线,采用MMPTE对其进行优化。仿真结果验证了最大功率传输效率法在设计微波多波束阵列时具有良好的优化效果。 相似文献
6.
讨论利用加权最大功率传输效率法(Weighted method of maximum power transmission efficiency,WMMPTE)实现多波束阵列天线的稀疏化,使得天线单元数目小于天线波束数数目.待设计天线与置于波束方向的测试天线形成无线功率传输系统,再利用WMMPTE优化可得到多波束阵列天... 相似文献
7.
本文针对多用户环境下的多天线正交频分复用下行系统,提出了一种新的基于迫零波束成型的用户调度算法。迫零波束成型是在发送端消除用户间的干扰生成多个独立的空间子信道,来实现空间复用。由于在多天线正交频分复用下行系统中最优的用户选择算法需要遍历所有可能的用户集合,算法复杂度非常大,本文提出了一种简化算法。所提算法在保证每个用户的速率要求的情况下,通过贪婪算法来选择每个子载波上的用户集合,以最小化系统的发送功率。仿真结果表明在满足用户的速率要求下能达到很好的系统性能。 相似文献
8.
针对工作于underlay模式的认知无线网络(CRN,Cognitive Radio Network)上行功率控制问题,本文提出一种基于多天线波束赋形,由认知基站和认知用户联合优化的分布式上行功率控制算法.联合优化的具体步骤为认知基站通过求解最大广义特征值问题完成多天线波束赋形优化;认知用户先将非线性功率优化问题转换为几何规划凸优化问题,再使用梯度法完成分布式发送功率优化;认知基站和认知用户交替优化,实现网络效用最大化.数值仿真显示,同只优化认知用户功率的上行功率控制算法相比,认知基站和认知用户联合优化的上行功率控制算法不仅能得到更大的网络效用值,而且对主用户的干扰具有鲁棒性. 相似文献
9.
本文研究了全双工中继协作下的认知MIMO系统的平均吞吐量最大化问题。与传统的中继协作认知无线电系统不同的是,该系统模型中的双工中继节点既能协助认知用户源节点进行多天线频谱感知以提高频谱检测性能,也能解码转发认知用户源节点的发送信号以获得更大的系统吞吐量。为使系统平均吞吐量最大,首先,本文以认知用户能获得的最大平均频谱空洞被发现的概率为目标,对系统的帧结构进行优化以获得最佳的感知时间,接着对多个发送天线进行优化以选择出最佳的发送天线,并推导出了在总的发送功率和对主用户干扰受限条件下的认知用户源节点和双工中继节点的最佳功率分配方案。最后的仿真结果表明本文提出的系统模型和优化方案相比传统的双工等功率分配方案以及单工功率分配方案能够获得更大的系统平均吞吐量。 相似文献
10.
11.
第五代(5G)移动通信网络将会在很大程度上提高无线通信的速率。由于多入多出系统(MIMO)能够满足5G网络中对信息速率越来越高的要求,现在正受到广泛的关注。然而,传统意义的二维(2D)MIMO技术仅仅能控制水平维的波束。为了满足5G的需求,需要引入能同时考虑水平维和垂直维波束的三维(3D)MIMO技术。本文基于3D MIMO信道模型,在分析3D MIMO信道相关性的基础上,针对发射相关和接收相关矩阵在水平维和垂直维的分解,提出了一种利用3D MIMO信道相关性的有限反馈预编码方案。并在此基础上,结合2D MIMO信道下的DFT码本和Grassmannian码本,提出了两种新的3D MIMO信道下的码本。实验结果表明,提出的3D MIMO预编码方案整体性能优于传统2D MIMO和现有的3D MIMO预编码方案。在3D MIMO系统中,由于可以动态调节天线的下倾角,故充分发掘了空间三维自由度。3D MIMO预编码技术减小小区间干扰,增加了系统容量,有效地提高了整个通信系统的性能。 相似文献
12.
针对任意三维到达波角度分布时,接收天线阵列的空域相关性评估比较复杂,通常只能采用数值积分方法的问题,本文提出了一种基于角谱域脉冲采样的三维空域相关性评估快速算法。该算法首先利用特定采样脉冲对三维入射波功率角谱进行二维采样,然后根据采样脉冲的空域相关系数加权叠加获得不同天线接收信号之间的空域相关性,大大降低相关性计算的复杂度。同时,文中还推导获得基于最小均方误差准则的采样脉冲表达式及其对应的空域相关系数精确解析式和近似表达式。仿真和分析结果表明,当角谱域采样间隔小于10度时,该快速算法的最大误差小于0.01,但运算时间远远小于数值积分方法及其它评估方法,可满足信道估计和天线阵列设计等实际需求。 相似文献
13.
In this paper, a multicast concept for device-to-device (D2D) communication underlaying a cellular infrastruc~tre is investigated. To increase the overall capacity and improve resource utilization, a novel interference coordination scheme is proposed. The proposed scheme includes two steps. First, in order to mitigate the interference from D2D multicast transmission to cellular networks (CNs), a dynamic power control scheme is proposed that can determine the upper bound of D2D transmitter power based on the location of base station (BS) and areas of adjacent cells from the coverage area of D2D multicast group. Next, an interference limited area control scheme that reduces the interference from CNs to each D2D multicast receiver is proposed. The proposed scheme does not allow the coexistence of cellular user equipments (CUEs) located in the interference limited area to reuse the same resources as the D2D multicast group. From the simulation results, it is confirmed that the proposed schemes improve the performance of the hybrid system compared to the conventional ways. 相似文献
14.
Device-to-Device (D2D) multicast will become an important technology with the increasing requirements of local communication services in future networks. To increase the overall capacity and improve resource utilization, a novel interference coordination scheme is proposed. The proposed scheme includes three steps. First, in order to mitigate the interference from D2D multicast transmission to cellular networks (CNs), a dynamic power control scheme is proposed that can determine the upper bound of D2D transmitter power based on the location of Base Station and areas of adjacent cells from the coverage area of D2D multicast group. Next, an interference limited area control scheme that reduces the interference from CNs to each D2D multicast receiver is proposed. The proposed scheme does not allow the coexistence of cellular equipments (CUEs) located in the interference limited area to reuse the same resources as the D2D multicast group. Then two resource block (RB) allocation rules are proposed to select the appropriate RBs from a candidate RB set for D2D multicast group. From the simulation results, it is confirmed that the proposed schemes improve the performance of the hybrid system compared to the conventional ways. 相似文献
15.
文章研究了基于大规模多输入多输出(multiple-input multiple-output,MIMO)和端到端(device-to-device,D2D)技术的双层混合网络及其能量效率,面向D2D用户(D2D user,DU)提出了无线能量采集方案。在该混合网络模型中,宏蜂窝基站由大规模MIMO天线阵列构成,D2D网络覆盖在宏蜂窝之上,与蜂窝网共享频谱。为了保证D2D通信,系统配置了由小规模MIMO天线构成的专用能量发射基站(power beacon,PB),其通过迫零预编码向能量约束的D2D发射机传送能量;同时,为了提高网络的能量效率,DU还可以从附近蜂窝网用户(cellular user,CU)的射频(radio frequency,RF)干扰信号中采集能量。对此混合网模型和能量采集方案,文章通过假设网络中CU、DU以及PB的位置服从独立泊松点过程和利用随机几何分析方法,基于反功率控制方案得到了网络中任一D2D发射机通过采集足够能量来建立通信链路的概率,其以简单的积分形式给出。分析和数值结果表明,文章提出的无线能量采集方案由于PB的配置保证了D2D通信的可靠性;同时又因为充分利用了附近CU的RF干扰信号,有效提高了D2D用户采集足够能量的概率,节约了PB的能量,改善了系统的能量效率。 相似文献
16.
17.
Yongmei Dai Zhongding Lei Sumei Sun 《Communications Letters, IEEE》2004,8(8):526-528
The zero-forcing interference suppression and cancellation scheme proposed by Tarokh et al., in 1999, for grouped space time coded system suffers performance loss due to limited diversity gains for the first detected antenna groups, and power allocation was suggested to overcome this problem. In this letter, we propose an ordered detection algorithm which compensates the diversity loss by always detecting the group with the strongest post-ing signal-to-noise ratio. Compared with the power allocation scheme, our proposed scheme is more robust to varying channel conditions and when used with iterative interference cancellation, a performance gain of 2.4 dB can be obtained at a frame-error rate rate of 10/sup -2/. 相似文献
18.
Cellular radio networks continuously evolve to respond the exponential growth in data traffic volume in mobile communications. Active antenna technology contributes to this evolution by introducing vertical sectorization, which splits the horizontal sector into two subsectors with respect to the elevation plane and doubles the number of cells that can be deployed. However, in order to guarantee a reliable and near-optimal operation of vertical sectorization in a system that applies universal frequency reuse, such as LTE-advanced, co-channel interference mitigation is essentially needed. In this article we propose a decentralized self-optimization method that can be used to mitigate the undesirable inter-cell interference by self-tuning the electrical antenna downtilt toward the optimal antenna elevation angle. The performance evaluations for the proposed self-optimization method are carried out for both coordinated and uncoordinated subsector transmission scenarios within the LTE-advanced framework using a dynamic LTE-advanced compliant system level SON simulator. Based on the extensive performance evaluations carried out for a realistic urban scenario, it is found that self-optimization improves the vertical sectorization performance 25 % in terms of virtual load. Furthermore, the performance gain reaches up to 30 % when vertical vectorization is provided with dynamic point selection and muting feature. Therefore, the article concludes that in LTE-advanced networks vertical sectorization can largely benefit from the antenna self-optimization and outperform the traditional horizontal sectorization approach with low algorithmic complexity. 相似文献
19.
TD-LTE同频干扰抑制技术研究与应用 总被引:1,自引:1,他引:0
TD-LTE同频组网会使小区边缘重叠覆盖区域内产生同频干扰,严重影响小区边缘吞吐量.本论文创新提出一种干扰抑制技术,该技术基于GIS信息,通过泰森多边形原理构建蜂窝小区覆盖区域,精确计算小区覆盖面积,由小区覆盖面积求出小区覆盖等效半径,根据天线高度与覆盖半径之间的三角函数关系,确定基站天线的下倾角,在保证满足切换要求的连续性覆盖前提下,尽可能减小小区间的重叠覆盖,有效提升小区边缘吞吐量. 相似文献