A Channel Sharing Scheme for Cellular Mobile Communications

This paper presents a channel sharing scheme, Neighbor Cell Channel Sharing (NCCS) , based on region partitioning of cell coverage for wireless cellular networks. Each cell is divided into an inner-cell region and an outer-cell region. Cochannel interference is suppressed by limiting the usage of sharing channels in the inner-cell region. The channel sharing scheme achieves a traffic-adaptive channel assignment and does not require any channel locking. Performance analysis shows that using the NCCS scheme leads to a lower call blocking probability and a better channel utilization as compared with other previously proposed channel assignment schemes.     

Dynamic Flow Model for Borrowing Channel Assignment Scheme in Cellular Mobile System

A mathematical model that predicts the dynamic flows in cellular mobile networks that allocate channels using the Borrowing Channel Assignment (BCA) scheme is described in this paper. Two types of handoff procedures – the prioritized and non-prioritized schemes – will be considered in the model. Discrete event simulations were performed and the results were found to be comparable to the results obtained using the mathematical model. Application to comparative study of the dynamic behaviours of the BCA and the Fixed Channel Assignment (FCA) schemes is also presented.     

两跳蜂窝移动系统中继信道分配策略

在频率复用因子为1的两跳固定中继节点的蜂窝移动通信系统中,基于现实移动业务分布的时变性和非均匀性,提出了新的中继信道分配策略。与传统的中继信道分配策略相比,该策略不需要BS之间的协作,也能严格控制相邻小区之间同频RS的干扰距离,降低同信道干扰,在较低的系统复杂度下,实现了无线资源的有效利用。     

Dynamic Flow Model for Borrowing Channel Ordering Assignment Scheme in Cellular Mobile Systems

A mathematical model that predicts the dynamic flows in cellularmobile networks that allocate channels using the Borrowing ChannelOrdering Assignment (BCO) scheme is described in this paper. Two types ofhandoff procedures – the prioritized and non-prioritized schemes –will be considered in the model. Discrete event simulations wereperformed and the results were found to be comparable to the resultsobtained using the mathematical model. Application to comparative studyof the dynamic behaviours of the BCO, the simple borrowing channel assignment(BCA) and the Fixed Channel Assignment (FCA) schemes is also presented.     

一种通用宽带MIMO信道模型

针对宽带的MIMO信道建模问题,提出一种通用多天线信道模型及其构造方法.该方法把克罗内克积应用到频域,同时提出频域散射衰落加权因子的概念,由此导出一种室外宽带MIMO散射分布模型.经过简化,该模型还可以应用到室内场景.仿真结果表明,这种通用信道模型能够准确的描述出宽带MIMO信道的视距(LoS)、非视距(NLoS)、室内外散射特征以及孔径效应.     

蜂窝移动通信系统中一种热点业务分配算法

基于提出的最优组合业务量预测模型,对下一时刻的业务量进行预测,从而确定蜂窝系统中业务分布情况,据此将蜂窝小区分成冷点区域和热点区域,并提出一种优化的混合信道分配(OHCA)方案,分析并给出了该方案中动静信道比的定量关系。仿真结果证实了该最优组合预测模型较单一预测方法降低了预测误差、提高了预测精度,同时该优化分配算法较固定信道分配(FCA)和动态信道分配(DCA)方案,有较小的呼阻率和较高的频谱利用率,该策略可用来有效处理热点业务问题,有较好的应用前景。     

一种适用于非城市区域的卫星移动信道统计模型

本文提出了一种适用于非城市区域的卫星移动信道统计模型—莱斯 K模型 ,采用K 分布来描述由于遮蔽引起的接收信号包络的缓慢变化 ,用莱斯分布来描述包含直视信号分量 (主径 )在内的多径快衰落 ,得到了接收信号包络的概率分布和误比特率 .在此基础上 ,本文利用样本矩对莱斯 K模型参数进行了估计并对参数估计性能进行了评价 .最后 ,本文利用实测数据对模型进行了验证 .     

天然粗糙面杂波中雷达目标的检测

本文引入时变分形曲面描述天然粗糙面的局部动态特征,给出三个合理电磁散射假设,采用基尔霍夫解定性分析散射的时域分形特性,导出天然粗糙面杂波的分形模型.根据随机分形信号小波系数近似不相关的特性,提出小波白化滤波—相关检测法,并详细论述了该方法的相关理论.理论分析和实验表明,天然粗糙面杂波符合分形模型,文中所提出的方法可以有效地实现杂波中雷达目标的检测.     

蜂房移动通信系统的信道下界

本文提出了蜂房移动通信系统中无三阶互调带宽信道数的下界公式。根据该公式得到最小带宽信道数。本文还给出了实际带宽信道数和无三阶互调信道组。     

A Simple 3-D Geometric Channel Model for Macrocell Mobile Communications

One of the fundamental research areas in wireless communications is the development of realistic models that can efficiently and accurately describe the wireless propagation channel. Most of the proposed models disregard the three dimensional character of the signal spread or use techniques with excessive computational complexity. In this paper, we develop a simple 3-D geometric scattering model for the uplink of a macrocell mobile environment that provides the statistics of Angle-of-Arrival (AoA) of the multipath components. The model extends the 2-D geometrical-based single bounce macrocell (GBSBM) model. Explicit closed-form expressions are derived for the statistics of the AoA of the multipaths in the azimuth and elevation planes. Analysis of the results exhibits the advantages of our proposal compared to 2-D and 3-D ones published in the literature. Comparisons with experimental data confirm its validity. Interesting conclusions for the effective evaluation of mobile communication systems have been derived. Moreover, an application of the model to mobile location estimation has been developed and evaluated.     

移动通信系统信道分配的方案与算法综述

由于移动通信的迅速发展，使得大量增长的业务需求与有限的频率资源之间的矛盾日益突出，因此如何更有效地提高频率的利用率，已成为本行业发展的关键。本文主要是针对小区制蜂窝系统在信道共用的情况下，如何进一步提高信道利用率的问题进行了研究，并在对目前提出的各种信道分配方案分析和比较的前提下，阐明了各自的特点和适用范围。     

无线移动信道特性分析

为了更快捷方便地搭建无线通信网络,对由多径效应和多普勒频移引起的大尺度衰落和小尺度衰落等信道特性进行了分析,总结其一般的传播规律,并利用Matlab软件对路径损耗模型及平坦衰落模型进行了仿真分析,为无线通信研究人员分析和仿真信道提供基础。     

A New Distributed Dynamic Channel Assignment Strategy in a Cellular Mobile Communication Network

A distributed dynamic channel assignment (DDCA)plays an important role in a microcellular mobilecommunication network. This paper proposes a new DDCAscheme based on channel priority (PDCA). This new strategy uses the cochannel interference andchannel reuse frequency to define the channel priority.The strategy improves performance of the forced calltermination rate and interference rate applied to multimedia traffic. Simulation results showthat the proposed PDCA strategy significantly improvesthe forced call termination rate and interference ratewhile keeping the blocking rate at an acceptable level.     

D-CAT: An Efficient Algorithm for Distributed Channel Allocation in Cellular Mobile Networks

We propose a distributed channel allocation algorithm based on a threshold scheme, called D-CAT, for cellular mobile networks. The algorithm employs two thresholds: (i) a heavy threshold for determining whether a cell is heavy, or overloaded, and for triggering the channel allocation algorithm; and (ii) a target threshold for indicating the target number of free channels that a heavy cell intends to acquire. Based on the two-threshold scheme, the D-CAT algorithm can determine the optimal number of free channels as well as the cell(s) from where a heavy cell should import channels in order to satisfy the required channel demand. Simulation experiments and analyses show that the proposed algorithm incurs lower overhead for channel allocation and is more efficient in terms of channel utilization than other distributed channel allocation algorithms. It also outperforms other centralized and distributed algorithms in terms of call blocking probability.     

The Effect of Channel Coding on the Efficiency of Cellular Mobile Radio Systems

Error correcting codes have two opposite effects on the efficiency of cellular mobile-radio systems. Although they increase the bandwidth per channel, the codes also make signals more robust and thereby reduce the required distance between users of the same frequency band. This paper reports a mathematical study of the interactions of these two effects in determining the efficiencies of a large number of sourcecode and channel-code combinations. Within a statistical performance objective (basebandSNR geq 11dB for 90 percent of the users), the most efficient scheme in this study has an embedded differential pulse code modulation (DPCM) source code and a rate 1/2 channel code that protects 2 bits of each 4 bit DPCM code word. Based on a conservative model of cellular transmission, we estimate that the bandwidth efficiency is 3 users/cell/MHz of system bandwidth. By contrast, there are only 1.2 users/cell/MHz with uncoded transmission and 4.5 users/cell/MHz with a rather complicated variable-rate scheme. We also observe that the embedded source code, originally devised for variable-rate operation, has a higher baseband SNR than conventional DPCM in certain fixed-rate environments.     

蜂窝移动通信系统中的一种新的优化信道分配模型

本文提出了一种新的蜂窝移动通信系统最优信道分配模型.首先根据信道分配的特点构造了一种信道分配方程模型;进而建立了信道分配最优模型,利用Pontryain最小值原理获得了模型的最优解;给出的仿真结果验证了分析结论的正确性.该模型可以用来有效地研究信道分配问题的宏观性能,并提供了一种高效、快速的算法.     

短波移动信道的仿真模型分析

在通信系统的研制和开发过程中,常常要考虑信道的传输特性,文中针对短波移动信道的特点,建立了小尺度衰落的短波移动信道的数学模型和计算机仿真模型,并对计算机仿真结果进行分析后,验证了该信道模型的可行性.该计算机仿真模型为比较各种抗多径衰落技术提供了一种有效的实验室仿真工具.     

一种用于移动终端的联合信道译码器

对移动终端中使用的信道译码技术进行了介绍，指出未来的移动终端需要支持多种通信标准。设计了一种用于移动终端的联合信道译码器，可支持多种通信标准，达到最大限度利用共享资源，从而节省总体成本。