Design aspects of satellite–cellular hybrid wireless systems

In this paper we investigate various issues related to the design of satellite–cellular hybrid systems. First, we review the fundamental problems of channel partitioning and call admission/assignment. Second, we study the impact of different frequency reuse constraints, in both layers, on the optimum channel partitioning. Third, we investigate, analytically and via simulation, the effect of reducing the cell size. We emphasize the blocking‐forced termination probabilities trade‐off for pure cellular and satellite–cellular hybrid systems. Accordingly, an optimization problem with respect to the cell size is formulated. Finally, we search for the optimum dynamic call re‐assignment policy that improves the system capacity at the expense of the complexity associated with tearing down a connection in one system and setting‐up an alternative one in the other system. For a small hybrid system, we characterized the optimum re‐assignment policies that minimize the blocking probability, dropping probability, and a weighted cost function of these probabilities. Copyright © 2002 John Wiley & Sons, Ltd.     

考虑功率限制的WDM光网有效设计

提出了一种基于禁忌搜索技术的启发式算法有效波长与路由分配(RWA-TS-P)来解决考虑功率限制的WDM光网的优化设计。该算法建立在局部搜索贪婪算法RWA-greedy之上,引入了功率验证过程来保证建立光路的功率有效性。通过环网和网状网的设计实例验证了算法的性能。数值结果表明,该算法能够在保证网络中建立的所有光路功率有效性的前提下最优地配置网络资源,同时具有可以控制的计算复杂性。     

Comparing Three Heuristic Search Methods for Functional Partitioning in Hardware–Software Codesign

This paper compares three heuristic search algorithms: genetic algorithm (GA), simulated annealing (SA) and tabu search (TS), for hardware–software partitioning. The algorithms operate on functional blocks for designs represented as directed acyclic graphs, with the objective of minimising processing time under various hardware area constraints. Thecomparison involves a model for calculating processing time based on a non-increasing first-fit algorithm to schedule tasks, given that shared resource conflicts do not occur. The results show that TS is superior to SA and GA in terms of both search time and quality of solutions. In addition, we have implemented an intensification strategy in TS called penalty reward, which can further improve the quality of results.     

On the Design Problem of Cellular Wireless Networks

In this paper, we deal with the problem of how to design cellular networks in a cost-effective way. We first propose an optimization model that deals with selecting the location of the base station controllers (BSCs) and mobile service switching centers (MSCs), selecting their types, designing the network topology and selecting the link types. In order to find a “good” solution, we propose a tabu search algorithm. Numerical results show that the tabu search algorithm produces solutions close to a proposed lower bound.Steven Chamberland received the Electrical Engineering degree from the École Polytechnique de Montréal in 1994 and the Ph.D. degree in Operations Research in 1998 also from the École Polytechnique. From 1998 to 1999, he was with the network architecture group of Bell Canada and from 1999 to 2001, he was a professor at the École de technologie supérieure. Since 2001, he has been an assistant professor of Computer Engineering at the École Polytechnique de Montréal. His research interests include telecommunication network planning and design and network architecture. Dr. Chamberland is a member of IEEE and ACM. E-mail: steven.chamberland@polymtl.caSamuel Pierre received the B.Eng. degree in Civil Engineering in 1981 from the École Polytechnique de Montréal, the B.Sc. and M.Sc. degrees in mathematics and computer science in 1984 and 1985, respectively, from the Université du Québec, the M.Sc. degree in economics in 1987 from the Université de Montréal and, the Ph.D. degree in Electrical Engineering in 1991 from the École Polytechnique de Montréal. He is currently a professor of Computer Engineering at the École Polytechnique de Montréal where he is Director of the Mobile Computing and Networking Research Laboratory and the NSERC/Ericsson Industrial Research Chair in Next- Generation Mobile Networking Systems.Dr. Pierre is the author of four books, co-author of two books and six book chapters, as well as over 200 other technical publications including journal and proceedings papers. He received the Best Paper Award of the Ninth International Workshop in Expert Systems & their Applications (France, 1989), a Distinguished Paper Award from OPNETWORK’2003 (Washington, USA). One of these co-authored books, Télécommunications et transmission de données (Eyrolles, 1992), received special mention from Telecoms Magazine (France, 1994). His research interests include wireline and wireless networks, mobile computing, performance evaluation, artificial intelligence, and electronic learning. He is a Fellow of Engineering Institute of Canada, senior member of IEEE, a member of ACM and IEEE Communications Society. He is an Associate Editor of IEEE Communications Letters and IEEE Canadian Review. He also serves on the editorial board of Telematics and Informatics published by Elsevier Science. E-mail: samuel.pierre@polymtl.ca     

面向无人机毫米波高效波束搜索的码本优化设计

针对无人机(UAV)动态环境下,波束无法实时匹配这一问题,结合毫米波数字-模拟混合波束形成系统,提出采用一种低复杂度的码本设计方法,以提高波束搜索效率。该方法首先建立了分层波束搜索模型并提出以扇形波束作为训练波束;其次将扇形波束的阵列响应改写为傅里叶级数形式,并利用傅里叶反变换得到扇形波束的理想数字码本;最后通过几何贪婪(Greedy Geometric, GG) 算法设计数字基带预编码器和射频预编码器,得到了具有快速搜索能力的优化波束。仿真结果表明,该码本优化方法具有较低的复杂度,有效地提高了波束搜索效率,满足了无人机实时波束匹配需求。     

Formulation and Computationally Efficient Algorithms for an Interference-Oriented Version of the Frequency Assignment Problem

The frequency assignment problem will maintain its importance for several years, since future versions of legacy cellular systems, e.g., those of GSM, will continue to exist. This paper elaborates on an interference-oriented version of the frequency assignment problem. The objective function is associated with the interference levels that are imposed by the frequency allocation, while the constraints are related to the allocation of the frequencies required in each cell and the prevention of some unacceptable interference situations. The problem is formally stated, mathematically formulated and solved by means of computationally efficient heuristics. Finally, results are obtained and concluding remarks are made.     

Efficient Beam‐Training Technique for Millimeter‐Wave Cellular Communications

In this paper, a beam ID preamble (BIDP) technique, where a beam ID is transmitted in the physical layer, is proposed for efficient beam training in millimeter‐wave cellular communication systems. To facilitate beam ID detection in a multicell environment with multiple beams, a BIDP is designed such that a beam ID is mapped onto a Zadoff–Chu sequence in association with its cell ID. By analyzing the correlation property of the BIDP, it is shown that multiple beams can be transmitted simultaneously with the proposed technique with minimal interbeam interference in a multicell environment, where beams have different time delays due to propagation delay or multipath channel delay. Through simulation with a spatial channel model, it is shown that the best beam pairs can be found with a significantly reduced processing time of beam training in the proposed technique.     

基于Android的电话号码查询系统设计

介绍了Android操作系统,以及基于Android的电话查询系统的关键技术,对该系统的具体设计与部分实现过程进行了阐述,给出了系统运行结果。经测试,该系统能在目前主流的Android移动设备如手机、平板电脑上正常运行,该系统立足于常用生活电话信息查询,为生活服务提供了方便。     

一种高效实用的直接数字频率合成器的设计和实现

在介绍DDS原理和特点的基础上，充分利用正弦函数的对称性，给出了DDS的一种实现方案，详细阐述了用FPGA实现该方案的方法，文章的最后给出了仿真结果。     

红外搜索跟踪系统中实时图像配准的研究和实现

为实现在红外探测器运动的条件下地面弱小目标的快速搜索与跟踪,提出了一种基于相位相关法配准和角点法配准相结合的红外图像配准方法实现对红外图像的运动补偿.根据相位相关法配准和角点法配准的特点,首先利用相位相关法对运动中的红外图像进行粗配准,然后利用相位相关法配准的结果作为角点法配准的先验信息实现图像的高精度配准.实验结果表明该算法能够在不降低配准精度的条件下,实时地为红外搜索跟踪系统提供红外图像的位移信息,有效地提高了红外搜索跟踪系统对弱小目标的检测率和检测精度.     

一种综合射频系统SCA软件平台的设计与实现

针对机载综合射频开放式系统架构,为了在软件综合层面上实现波形应用软件与具体平台的解耦,设计并实现了一种基于软件通信架构(Software Communication Architecture, SCA)的软件平台及其环境工具,解决了机载平台软件的分布式通信、资源调度管理、系统建模等技术问题,从而实现功能、应用和波形的组件化与动态重构。测试验证与工程应用情况表明,软件平台能够满足机载领域信号、信息处理强实时、高可用的应用需求,可有效提升综合射频系统软件开发质量与集成联试效率。