Cross-layer design proposals for wireless mobile networks: a survey and taxonomy

Third-generation (3G) and beyond 3G mobile communication systems must provide interoperability with the Internet, increase throughput for mobile devices, and optimize their operation for multimedia applications. The limited ability of traditional layered architectures to exploit the unique nature of wireless communication has fostered the introduction of cross-layer design solutions that allow optimized operation for mobile devices in the modern heterogeneous wireless environment. In this article we present the major cross-layer design solutions that handle such problems, and discuss cross-layer implementations with a focus on functional entities that support cross-layer processes and the respective signaling. In addition, we consider the associated architectural complexity and communication overhead they introduce. Furthermore, we point out the major open technical challenges in the cross-layer design research area. Finally, we conclude our article with a summary of cross-layer approaches developed thus far and provide directions for future work.     

Cross-layer analysis of protocol delay in mobile devices receiving BCMCS

Broadcast and multicast services allow the high-speed delivery of multimedia content to multiple subscribers over CDMA2000 wireless networks. This relies on a high-rate broadcast packet data system with an air interface governed by two interacting protocols: the medium access control (MAC) protocol specifies the methods of multiplexing and of forward error correction used to reduce the radio link error-rate seen by the higher layers; and the security protocol specifies the procedures used to encrypt and decrypt content, following the Advanced Encryption Standard. We investigated the mutual effect of these protocols, in the context of an ARM9-based mobile platform, and their influence on delay. This allowed us to propose a novel analytic model that can predict the total delay by summing the separate but related delays incurred by implementations of the MAC and security protocols with particular parameters. This cross-layer model includes the characteristics of error control in the MAC layer and the varying condition of the fading channel in the physical layer. We can use this model to estimate the size of data buffers that mobiles require to provide a seamless multimedia service.     

Cross-layer design of P2P file sharing over mobile ad hoc networks

Peer-to-peer file sharing over mobile ad hoc networks (MANET) has become a popular application due to the rapid growing number of mobile devices. However, the fact that mobile nodes in a MANET dynamically alter their locations and join/leave the P2P system has posted many challenges in designing a robust and scalable P2P system. Although, in the literature, flooding-based P2P approach has been shown to be robust in a highly dynamic network, it leads to poor efficiency in terms of bandwidth usage and scalability. A new design is required in which cross-layer designs and cognitive approaches could be applied such that it could interact with the requests of users and respond to dynamic change of network topology. In this paper, we propose an efficient and scalable P2P file sharing system over MANET based on Swarm Intelligence, referred to as P2PSI. By applying the cognitive behaviour of the real ant colonies, P2PSI owns the capability of adaptive learning of routing path and is able to cope with mobility problem without flooding. Moreover, P2PSI also adopts cross-layer design to reduce the redundant message overhead and query latency. Performance of P2PSI is evaluated and compared to two existing cross-layer design service discovery protocols through simulations. Our simulation results show that P2PSI achieves better performance in terms of control overhead and request success ratio.     

多跳分集系统中一种新的基于无比率编码的跨层方案

研究了多跳分集系统中由于链路的不可靠传输直接应用实用网络编码存在差错的扩散和传播问题.提出了一种新的基于无比率编码的跨层方案,该方案利用无比率编码的纠错能力及实用网络编码码字随机特性,控制了输入链路的差错扩散和传播.结果表明,在满足每条链路误包率一定的情况下,该方案获得了较好的差错性能.进一步分析了为了使每条链路达到给定的误包率,无比率编码在不同信噪比下的冗余.     

Optimal design for cellular mobile systems

Cellular zone design parameters for a land mobile communication system are clarified. System parameters having a strong influence on cellular system performance are discussed and some problems encountered when system parameters are changed are examined.     

移动平台下运动目标检测的MOF算法

建立了基于摄像机焦点运动所引起的场景全局运动的视差补偿技术（MOF）。摄像机自由移动时,由于场景的景深所带来的视差问题,需要对摄像机运动引起的场景全局运动进行补偿。重点研究了摄像机视角下摄像机与图像序列间光流场之间的运动关系,并实现了表征场景全局运动的MOF模型的建立。从摄像机视角的角度,利用射影几何的关系推导出光流场的约束条件,由场景的整体运动推测摄像机的运动,从而剔除视差虚警。最后,利用实际采集的图像数据进行实验,并与相关算法进行了分析对比,最终给出了MOF算法在摄像机平移、旋转等情况下的运动目标检测效果。     

移动机器人的动态目标实时检测与跟踪

通过移动机器人的视觉系统可以实现动态目标的 检测与跟踪。提出一种基于改进的高斯混合模型(GMM)的 实时动态目标检测算法,算法引入分块思想,在模型更新过程中动态调整GMM分布数目和学 习率,通过改进匹配准则来减小误检率(FPR)和漏检率(FNR) 。在目标检测的基础上,采用一种融合均值偏移(MS:Mean Shift)和粒子滤波(FP:Particl e Filter)的算法对 目标实时跟踪,在利用MS算法获得的最优候选区域周围散布采样粒子,根 据偏移向量的大小自适应调节粒子数目,不仅具有较快的收敛速度,且对遮挡具有较好的鲁 棒性。实验结 果表明,将两种改进后的算法应用于移动机器人的视觉系统中,能够对动态场景中的动态目 标实时检测与跟踪,较传统算法在实时性和精确性上均获得一定提高。     

无线移动通信中的OFDM系统参数设计方法

基于OFDM系统工作原理和无线移动通信信道时频二维衰落特性，研究OFDM系统的参数（包括子载波个数和循环前缀长度）设计准则，并用一个设计实例和仿真结果加以验证说明。研究结果可为OFDM系统的设计提供理论依据。     

Radio link design of cellular land mobile communication systems

A procedure for a radio link design of cellular land mobile radio systems is discussed. The relation between the prescribed total outage and the necessary margins for thermal noise and co-channel interference is first derived. It is then shown that the respective margins can be calculated separately. A simple and useful procedure for determining transmitter power and co-channel reuse distance is presented in concrete flowchart form. Based on this procedure, an example of a radio link design for a digital mobile telephone system is shown.     

Determining the target coordinates in forward-scattering radar systems with mobile stations

The maximum-likelihood method is applied to determination of the target coordinates in forward-scattering radar systems with mobile stations. Estimates of the potential accuracy of measurement are obtained. It is shown that forward-scattering radars with mobile stations can ensure almost the same accuracy of measurement of the target coordinates as radar systems with stationary stations.     

Mobile IP系统中的AAA接口研究与设计

在全IP无线互联网包分多址(PDMA)系统中,移动用户可以通过简单IP或移动IP两种接入方式接入Internet。如何对以上两种接入方式的用户提供基于RADIUS协议的身份认证、授权及基于流量方式的计费功能,是PDMA系统面临的一个重要问题。文章提出了支持微移动和宏移动两层协议体系分别进行AAA机制处理,以及两层AAA机制间有效协调的设计方案,在某地试验网的实际运行中取得了良好的效果。     

Movement detection analysis in mobile IPv6

Determining whether or not an IPv6 node has moved to a new subnet is not a simple issue in IETF Mobile IPv6. In this letter, we analyze the movement detection process of IPv6 mobile nodes qualitatively and quantitatively, and present the results of our performance analysis in terms of latency caused by the process.     

超低空掠海目标的微波探测系统设计

以低空突防技术研究为背景,从脉冲多普勒原理出发设计了微波探测系统,其主要目的实现对海面超低空来袭目标的有效探测。在实验室阶段实现了对移动目标的探测,针对微波探测进行了信号采集系统的电路设计与分析,并采用低通滤波和直流耦合的方式,得到目标信号。在探测实验中对脉冲产生电路,滤波电路及比较电路进行设计和分析验证。实验证明,该信号处理电路性能优良,工作可靠,对目标实现了有效探测。最后,根据实战情况对脉冲电路和滤波电路做了改进,能基本上满足超低空掠海目标的微波探测技术要求。     

不同采样体制对点目标的定量检测性能

围绕单采样和过采样扫描探测体制下的点目标定量检测性能,基于亚像元的采样模型,建立了一定分辨率条件下探测不同高度、尺寸目标的成像链路仿真模型,从目标信号采集能力、背景及杂波水平影响、检测能力和测量特性四个方面对比分析了相同瞬时视场的单采样、过采样以及两倍瞬时视场的过采样三种规格采样体制的目标检测性能。分析结果表明：相同瞬时视场的过采样比单采样更有利于目标信号的采集,检测能力更强,两倍瞬时视场的过采样对目标信号有抑制作用,不利于低信杂比情况下的目标探测;两种规格的过采样对背景信号及杂波均有抑制作用;两种规格的过采样对目标辐射强度都有明显的过采集误差,必须进行修正。     

Cross-layer design: a survey and the road ahead

Of late, there has been an avalanche of cross-layer design proposals for wireless networks. A number of researchers have looked at specific aspects of network performance and, approaching cross-layer design via their interpretation of what it implies, have presented several cross-layer design proposals. These proposals involve different layers of the protocol stack, and address both cellular and ad hoc networks. There has also been work relating to the implementation of cross-layer interactions. It is high time that these various individual efforts be put into perspective and a more holistic view be taken. In this article, we take a step in that direction by presenting a survey of the literature in the area of cross-layer design, and by taking stock of the ongoing work. We suggest a definition for cross-layer design, discuss the basic types of cross-layer design with examples drawn from the literature, and categorize the initial proposals on how cross-layer interactions may be implemented. We then highlight some open challenges and new opportunities for cross-layer design. Designers presenting cross-layer design proposals can start addressing these as they move ahead.     

无线mesh网的跨层设计及其应用

根据无线mesh网跨层设计的基本原理,分析了跨层设计系统中各模块的功能和各种需要考虑的因素。提出一种综合了无线mesh网高效的状态信息交换方法和先进路由算法的跨层设计实现方案,可根据网络当前链路状态、拥塞情况和能量等因素,合理选择传输路径。同时还给出了该方法在电网高压输电监控系统中的应用实例。仿真和实验表明所提方案在实际应用时在强壮性、吞吐量和时延等方面都有良好的性能。     

移动通信系统中宽带功放线性化设计与仿真

自适应数字预失真技术能够解决宽带高峰均比信号经过功放产生的非线性失真问题.主要介绍了自适应数字预失真的结构、预失真器的数学模型及相关的自适应算法.仿真结果表明采用自适应数字预失真技术能够显著地改善功放输出信号的带外频谱失真,是一种有效、灵活的技术.     

Game theoretic design for polarimetric MIMO radar target detection

Polarimetric radar systems allow the flexibility of transmitting arbitrarily polarized waveforms that match the scattering profiles of the target. Since different types of targets have varying profiles, the advantages of a polarimetric radar system can fully be exploited only when the type of target is accurately estimated. However, accurate estimation requires a significant amount of training data, which can be expensive. We propose a polarimetric design scheme for distributed multiple input multiple output (MIMO) radar target detection. We formulate the selection of transmit polarizations using a game theoretic framework by examining the impact of all possible transmit schemes on the detection performance with different available target profiles (see also Gogineni and Nehorai, 2011 [1]). This approach does not require training data, and we show a significant performance improvement due to the polarimetric design. Other radar design problems can also be solved using this game theoretic approach.     

应用于移动作业系统的安全检测算法研究

针对传统的安全检测方法无法有效应对移动网络恶意入侵问题,提出一种基于ID3决策树算法的安全检测算法。根据移动作业系统运行模型分析,设计相应的安全检测模型。通过TF-IDF对异常内容的敏感词进行权值计算和排序,并采用ID3决策树算法对解析后的数据进行分类,实验结果验证了提出的安全检测算法的有效性。相比于朴素贝叶斯算法,所提出算法具有较高的检测率。     

手机系统中一种看门狗复位的设计方案

在当今的手机系统中,都会用到一种外部看门狗芯片用来在系统出现程序跑死时,对系统进行复位,以便系统能够重新工作.但是市场上的看门狗芯片在功能和价格等方面都有一定的局限性.针对这些不足之处,提出了一种外部看门狗的设计方案.经过实际测试表明,该设计方案功能正确,运用起来方便灵活,且看门狗芯片成本有较大降低,因而可运用到实际的手机系统中.