MicroBusiness - Cellular Industry Competes for Broadband Business

Our previous column on WiMAX business prospects included a graph of the mobile WiMAX competitive environment. Many different versions of such graphs exist. What these graphs have in common is that they are all populated by a progression of cellular systems toward ever-higher broadband capabilities. The 4G target peak data rates agreed upon in ITU-R Working Party 8F for "Systems Beyond IMT-2000" (renamed "IMT-Advanced") are "up to approximately 100 Mb/s for high mobility such as mobile access and up to approximately 1 Gb/s for low mobility such as nomadic wireless access". The cellular industry is pursuing mobile broadband development toward these objectives along two distinct 3G/4G branches, one evolving from WCDMA and the other from CDMA2000. The former is spearheaded by the 3rd Generation Partnership Project (3GPP), and the latter by 3GPP2.     

5G TM 信号无线信道测量平台研究与实现

为了研究第五代移动通信（5G）系统无线信道，获得准确的5G无线信道特性和信道模型，提出了一种基于5G新空口（NR）测试模式（TM）信号的无线信道测量平台。开展了TM无线信道测量平台的总体架构及测量信号接收处理算法设计，并基于软件无线电设备和高性能计算设备搭建测量平台。针对功率谱平坦度、峰均功率比和相关性等指标，对多种TM信号的测量性能进行评估。根据性能评估结果，选择适合作为测量波形的TM信号。采用射频馈线直连、多径信道模拟和静态空口实测3种方法对TM无线信道测量平台进行验证，该平台不仅可以实现准确的信道测量，同时能够对矢量幅度误差和误比特率等传输性能进行测试。     

基于车载通信网络的认知无线电信道分配技术的研究

车载通信网络的移动性对无线网络的信道分配提出了高要求,认知无线电技术能适应这一要求。将认知无线电的信道分配技术运用到车载通信网络中,根据实际交通状况对车载通信网络进行建模,主用户和认知用户分别实体化为无线网络用户及车载通信用户;运用协作最大化带宽和（CMSB）算法对认知用户进行信道分配。仿真分析结果表明在给定的车载通信网络模型下,CMSB能极大地优化网络吞吐量,并能保证一定的分配公平性。     

User mobility support in an urban CDMA-based wireless network

A salient feature of wireless networks is the ability to support user roaming. However, user mobility has a profound effect on grade of service (GoS) and quality of service (QoS) provisioning. Code division multiple access (CDMA) is the multiple access technology for the third-generation wireless standard (3G) and is envisioned to be the multiple access technology beyond 3G. CDMA is interference-limited. The signal-to-interference (SIR) ratio, expressible in the form of Eb/I0, is an important parameter in CDMA systems and has a profound effect on the system capacity. The system capacity in turn affects the call-level GoS of the network layer in terms of new call blocking probability and forced termination probability. The effect of user mobility on (i) degradation in utilization and (ii) excess capacity needed to satisfy the QoS/GoS requirements, in an urban environment, is examined and quantified. A relationship between the link-layer Eb/I0 specification and the call-level GoS parameters in the presence of user mobility is also established. Numerical results which display the linkages between the link-layer QoS and call-level GoS parameters are presented and discussed. This coupling gives a quantification of the link-layer requirement to provision the call-level GoS, in the presence of user mobility.     

Predictive call admission control for multimedia streaming in CDMA cellular environments

Third-generation (3G) wireless networks based on code-division multiple access (CDMA) have been engineered to provide mobile users with voice as well as advanced packet data services. Support of Internet-based multimedia streaming services is considered a critical factor for future deployment of such networks. Provisioning streaming services in a dependable way, however, requires supporting data transmission at relatively high data rates while maintaining session quality during both intracell and intercell user movements. In this paper, an adaptive bandwidth allocation and admission control scheme is proposed for managing network resources for a streaming service. Streaming requests are assumed to be served by an adaptive server capable of choosing suitable video streaming parameters (e.g., video resolution, frame rate, and encoding parameters) in response to possible requests from the wireless network to vary the currently allocated bandwidth. The devised admission control scheme exploits a priori knowledge of user mobility patterns to minimize the risk of running into an overload condition after acceptance of a new multimedia streaming connection. The obtained simulation results show that, compared to a nonpredictive admission control scheme, the proposed scheme achieves a lower forced-termination probability and higher throughput, while consuming less base-station transmission energy.     

Radios for next-generation wireless networks

Next-generation wireless networks will support a wide range of data rates over several frequency bands and require adaptive and programmable system resources. Radio transceivers used in these wireless networks will incorporate self-calibration and full programmability to support their high performance and adaptivity. Low power designs at the circuit architectural, and overall system levels will enable longer battery life for portable devices. Many additional challenges exist in implementing high data rate programmable orthogonal frequency division multiplexing (OFDM) multiple-input/multiple-output (MIMO) radio transceivers that cover different frequency bands, maintain low current consumption, and are low cost. This article is an examination of the challenges in implementing high data rate programmable orthogonal frequency division multiplexing multiple-input/multiple-output radio transceivers that cover different frequency bands, maintain low current consumption, and are low cost.     

Mobility and the Internet

The Internet Protocol (IP) was never intended for mobility. Nevertheless, we need to provide this functionality without changing the underlying protocol. If we could start over again, hindsight would provide a wealth of wisdom in implementing a mobility protocol. However, given the installed base, the overriding design requirement must be to remain compatible with the standard IP. Mobile-IP must be able to support mobility for both wired and wireless local area networks (LANs). The Mobile-IP must be able to function in the harsh, wireless world where high error rates are the norm and bandwidth is limited. The paper considers how the design must accommodate a mobile host moving between wireless LANs, as well as between a wire and wireless LAN. It discusses the design requirements, multicasting and tunneling     

Comparisons of link-adaptation-based scheduling algorithms for the WCDMA system with high-speed downlink packet access

The wideband code division multiple access (WCDMA) system with high-speed downlink packet access (HSDPA) is an important next-generation wireless system. By adopting adaptive modulation, efficient scheduling, and hybrid automatic repeat request technologies, it can support data rates of up to 10 Mb/s in the mobile cellular environment. Among these techniques, the scheduling algorithm plays a key role in realizing the HSDPA concept. A good scheduling algorithm should consider all the important factors, including channel impact, delay issues, and fairness. In this paper, a fairness index is adopted to examine the fairness performance of current link-adaptation-based scheduling algorithms, including the maximum carrier-to-interference (C/I), round-robin, proportional fair, and exponential rule schedulers. It is found that when multi-type services are supported, the fairness performance of current scheduling algorithms, including the round-robin scheduler, can be further improved even though the round-robin scheduler is viewed as the scheduler of the greatest fairness. Thus, a new scheduling algorithm, namely the queue-based exponential rule scheduler, is developed. Through simulations, it is shown that in the context of multi-type services the fairness performance of the queue-based exponential rule scheduler can surpass that of all the other schedulers in the time-multiplexing fashion, while maintaining good throughput and delay performance.     

多跳中继通信网STDM模式链路容量分析

下一代基于中继节点的多跳蜂窝网络将支持更高速率的多媒体移动业务.多跳中继链路能够有效改善无线通信链路的信道质量,有利于系统容量的提高,但是中继节点的引入代价属于额外无线信道资源的消耗,将会降低系统容量.因此本文提出了空间时分复用(STDM)的多跳中继链路模型,使得中继无线信道资源能够空间复用,通过理论分析和数值仿真,在保证一定的链路距离下,与传统严格时间正交的模式相比,STDM模式的链路吞吐量可以成倍的提高.     

Physical relationships

There is continuing effort to increase the data transmission rate in evolving wireless systems. These evolving wireless systems include cellular mobile systems and wireless local area networks (WLANs). However, because of the complexity of these systems, it appears that fundamental physical relationships between transmission rate and the range over which transmission is possible are frequently overlooked. This can result in overly optimistic expectations for new wireless data systems or comparisons between systems that are not on an equal basis. This article reviews fundamental relationships between wireless system transmission rate (bit rate) and transmission range and includes the effects of some other system parameters on these relationships.     

Low complexity M‐PPM impulse‐radio ultra wideband over fiber system for wireless sensor networks applications

Ultra wideband over fiber (UWBoF) systems have been proposed to extend wireless range and to interconnect stand‐alone UWB networks. These systems have focused on high‐data‐rate applications. However, UWB will be a key enabler for low‐data‐rate wireless sensor network (WSN) deployments. In this letter, a low‐cost and low‐complexity M‐ary pulse position modulation (PPM) impulse radio (IR)‐UWBoF system designed for WSNs applications is proposed. A spectral line‐suppressive convolutional code is used to achieve spectral line suppression in the power spectral density (PSD). Experimental results show that the system does not distort or add spectral lines to the IR‐UWB signal PSD transmitted over 30 km of a single‐mode fiber, thus demonstrating its feasibility to interconnect WSN deployments. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Siliconization of 60 GHz

Silicon-based RF and microwave technology has had a dramatic impact on the world of wireless technology. We can now access voice/data and entertainment in virtually every corner of the globe--with everything from short range Bluetooth and WiFi networks to cellular and satellite networks--to meet different range and throughput requirements. A laptop computer without wireless capability is unthinkable today, whereas, ten years ago, these technologies were in their infancy.What do the next ten years hold? What gaps in wireless technology exist even today? Perhaps the most obvious missing link is between the various devices that we carry with us, such as cellular phones or personal digital assistants (or smart phones if you prefer), digital cameras, music and video players (such as the ubiquitous iPod), laptops, and peripherals such as external hard drives and monitors. The case of the mobile smart phone is particularly important since the existing wireless connectivity is either too slow and power hungry (Bluetooth) or designed and optimized for longer ranges (WiFi). What is missing is a wireless universal connectivity that can support high data rates demanded by large data rate multimedia applications. Wireless technology has been conspicuously absent from MP3 music players (such as Apple's iPod), which are ideal candidates for downloading music and video. While ultrawideband (UWB) technology using the 3--10 GHz band promised to fulfill these needs, it fell short in many ways, and, today, most of the start-up companies pursuing UWB have folded.     

TCP performance over mobile ad hoc networks

TCP is a transport protocol that guarantees reliable ordered delivery of data packets over wired networks. Although it is well tuned for wired networks, TCP performs poorly in mobile ad hoc networks (MANETs). This is because TCP's implicit assumption that any packet loss is due to congestion is invalid in mobile ad hoc networks where wireless channel errors, link contention, mobility and multipath routing may significantly corrupt or disorder packet delivery. If TCP misinterprets such losses as congestion and consequently invokes congestion control procedures, it will suffer from performance degradation and unfairness. To understand TCP behaviour and improve the TCP performance over multi-hop ad hoc networks, considerable research has been carried out. As the research in this area is still active and many problems are still wide open, an in-depth and timely survey is needed. In this paper, the challenges imposed on the standard TCP in the wireless ad hoc network environment are first identified. Then some existing solutions are discussed according to their design philosophy. Finally, some suggestions regarding future research issues are presented.     

Reconfigurable planar filters

Electronically reconfigurable or tunable microwave filters are attracting more attention for research and development because of their increasing importance in improving the capability of current and future wireless systems. For instance, emerging ultrawideband (UWB) technology requires the use of a wide radio spectrum. However, the frequency spectrum as a resource is valuable and limited, so the spectrum is always being used for several purposes, which means it is full of unwanted signals when an operation such as a UWB wireless system is concerned. In this case, existing undesired narrowband radio signals, which vary from place to place and from time to time, may interfere with the UWB system's range. A solution for this is to introduce an electronically switchable or tunable narrow rejection band (notch) within the passband of a UWB bandpass filter. Such an electronically reconfigurable filter is also desired for wideband radar or electronic warfare systems. This paper discusses the development of electronically reconfigurable filter types.     

多模无线通信技术在应急指挥系统中的应用

针对无线通信网络覆盖范围小、稳定性差、带宽低等问题,提出一种基于多模自适应无线通信技术的移动应急指挥系统设计方法.方法采用WiFi、多模3G以及卫星通信三模自适应通信技术,可同时接入CDMA2000、WCDMA和TD-SCDMA三种3G网络,利用多路同传、负载均衡策略实现多种异构无线通信网络的融合.采用此技术对移动应急...     

电动汽车接入电网的通信技术及其安全要求

电动汽车接入电网(V2G)将电动汽车与智能电网相结合,既解决了电动汽车大规模发展带来的充电压力问题,又可将电动汽车作为移动的、分布式储能单元接入电网。宽带无线和无线结合有线通信为V2G进行双向、实时和大容量数据信息交互提供了技术保障,安全可靠的通信技术是V2G发展的前提,是保障智能电网稳定运行的基础。本文首先讨论了V2G的通信技术,通过分析 4种通信技术在V2G中的应用比较,得出无线通信和无线结合有线通信将可以很好地解决V2G的通信问题。本文分析了V2G通信中所面临的安全威胁与安全需求,并给出V2G的通信安全框架,分析了各层次的安全目标,最后给出初步的安全实施策略。     

Performance analysis of proxy mobile IPv6 based on IEEE802.16e

Proxy mobile Internet protocol version 6 (PMIPv6) is a network-based mobility management protocol proposed by Internet Engineering Task Force (IETF), which allows nodes to remain service connectivity while moving around in the IPv6 Internet. PMIPv6 is different from the host-based mobility management protocols (mobile Internet protocol version (MIPv6), hierarchical mobile IPv6 (HMIPv6), fast handover for mobile IPv6 (FMIPv6), and fast handover in hierarchical mobile IPv6 (F-HMIPv6)), whose signaling are transferred among some network entities except mobile node (MN). This paper focuses on the analytical modeling of performance analysis for PMIPv6 and other protocols using IEEE802.16-based wireless metropolitan area networks as the wireless access network. The performances of these protocols are evaluated by some metrics like handover latency, service disruption time, and binding update cost. Numerical results show that PMIPv6 has better performance.     

Adaptive Power Control Protocol With Hardware Implementation for Wireless Sensor and RFID Reader Networks

The development and deployment of radio frequency identification (RFID) systems render a novel distributed sensor network which enhances visibility into manufacturing processes. In RFID systems, the detection range and read rates will suffer from interference among high-power reading devices. This problem grows severely and degrades system performance in dense RFID networks. Consequently, medium access protocols (MAC) protocols are needed for such networks to assess and provide access to the channel so that tags can be read accurately. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a desired read rate. The power control scheme and MAC protocol dynamically adjust the RFID reader power output in response to the interference level seen during tag reading and acceptable signal-to-noise ratio (SNR). We present novel distributed adaptive power control (DAPC) as a possible solution. A suitable back off scheme is also added with DAPC to improve coverage. A generic UHF wireless testbed is built using UMR/SLU GEN4-SSN for implementing the protocol. Both the methodology and hardware implementation of the schemes are presented, compared, and discussed. The results of hardware implementation illustrate that the protocol performs satisfactorily as expected.     

基于Cloud-RAN的协作式无线接入网架构

Cloud-RAN架构和CoMP技术是未来蜂窝移动通信的两个重要演进方向。基于Cloud-RAN的网络架构结合了信息通信技术领域最先进的云计算、虚拟化以及软件无线电等技术,具有维护升级简单、可扩展性强,基站调度灵活、能耗低,便于实现协作式无线传输技术等特点。CoMP技术是一种重要的协作式无线接入网技术,通过小区间的协作传输,可以有效降低小区间干扰,提高系统容量。通过将这两种技术融合起来,构建基于Cloud-RAN的协作式无线接入网,可以在多基站间进行高效的数据传递与共享,结合软件无线电技术,可以针对移动通信技术特征实现分层次的软件优化,通过使用多线程设计和指令集并行技术,提高软件运行效率,实现基于通用处理器平台的协作化无线接入网。基于Cloud-RAN的协作式无线接入网系统设计方案和实现优化方案具有一定的通用性,可以为未来Cloud-RAN架构和CoMP技术的融合提供参考。     

Mobile backhaul [From the Guest Editor's Desk]

This focused issue, which is a sequel to the August 2008 focused issue "Convergence and Competition on the Way Toward 4G" [1]-[7], addresses the mobile backhaul prospects from the various viewpoints of the contributing authors, whose interests are complementary. The term mobile backhaul is commonly used for the fixed wireline and/or wireless interconnections of mobile service base stations, and their connections to the core telecommunications network. The subject is of increasing interest in consideration of the following major trends: · cellular mobile services are rapidly growing worldwide · backhaul capacity requirements are substantially increasing as cellular mobile systems transition from 2G to 3G and to 4G · the transitioning of broadband wireline and wireless transport from legacy time-division multiplexing (TDM) and asynchronous transmission mode (ATM) to IP-based transport is accelerating · the backhaul parts of mobile networks account for ever increasing percentages of the total capital and operating expenses. These trends motivated the current focused issue to address mobile backhaul issues of particular interest to the readers of IEEE Microwave Magazine.