Unified wireless access in hot-spot environment

Convergence, interoperability, and mobility are the major advances and factors of differentiation in 3G networks, while the inherent IP support will boost new personalized multimedia services. However, the deployment of a global all-IP wireless/mobile network is not a straightforward decision. A phased approach, focusing on "hot-spot" locations with complementary wireless technologies, seems to be one of the most realistic alternatives. This article discusses a new architecture called unified wireless access that focuses on public "hot-spots." The major algorithms of UniWA are analyzed and evaluated, while the gain is presented and illustrated in selected graphs     

40~50 GHz固定无线接入系统干扰共存分析

为了分析在40.5~42.3 GHz和48.4~50.2 GHz频段引入固定无线接入系统的可行性,对该频带固定无线接入系统与频率划分表中各主要业务系统间的共存问题进行了研究。通过计算机静态建模方法,分析了此频段内固定无线接入系统对固定、卫星固定、广播、射电天文等业务系统的干扰功率密度随距离变化情况,并根据相关业务的干扰保护准则获得对不同业务的隔离距离,从而证明在一定隔离距离条件下,固定无线接入系统不易对同频段的主要业务造成有害干扰,可以在该频段引入固定无线接入系统。研究成果可支撑我国无线电频谱管理部门对该频段业务的再次划分。     

高比特3.5GHz固定宽带无线接入系统构建易于运营管理、可持续发展的灵活高效的宽带接入平台

当前,骨干网的建设已具备了相当的规模,然而接入网的建设还比较薄弱,且市场竞争不够充分,成为信息化建设的“瓶颈”。因此如何尽快妥善解决网络“最后一公里”的“瓶颈”,全面满足商业用户和住宅用户宽带接入的需求,已成为传统电信运营商和新兴电信运营商所面临的共同问题。随着网络宽带化进程的不断加快,电信竞争的焦点已由长途骨干转为本地接入,市场竞争要求接入手段多元化,在各种接入技术中,宽带无线接入凭借其组网快速灵活、运营维护方便及良好的成本竞争力,已迅速地成为市场的热点。 对于新兴的电信运营商来说能够以宽带无…     

On the scalability of fixed broadband wireless access network deployment

Fixed broadband wireless access systems, such as the local multipoint distribution service, use an open system architecture that supports a scalable solution for the Internet services over IEEE 802.16 wireless networks. This article presents an overview of various features of BWA systems toward realizing a high level of scalability to support a potentially fast expanding network. This is achieved by optimizing various network resources, which include utilizing the available bandwidth efficiency, making a minor enhancement to an existing system that minimizes the disruption to network services during the network expansion process, and combining the benefits of different features to increase network capacity.     

哈尔滨电信3.5G固定无线接入网络优化

分析哈尔滨电信3.5G固定无线接入网现状与存在问题,从基站扇区调整、容量调整、干扰解决、端站场强调整等几方面介绍网络优化措施.     

多信道多点分配系统-一种新的宽带固定无线接人技术

多信道多点分配系统（Multichannel Multipoint Distribution System MMDS）是近几年刚刚兴起和获得商业应用的宽带固定无线接入技术，它具有中宽带、中等数据传输速率以及应用灵活、设备安装速度快、投资少，收益大等特点，可以为中小企业提供各种宽带交互式数据，话音和视频传输业务，成为宽带接入技术中不可忽视的重要组成部分。     

Optimal DLC protocol configuration for realistic broadband fixed wireless access networks based on ATM

DLC protocols, scheduling, and multiplexing issues for broadband fixed wireless access networks based on ATM are discussed. The established DSA++ mac protocol has been developed at ComNets and has been widely applied within the German project ATMmobil. It has been a fundamental contribution to the etsi bran standardisation of HIPERLAN /2. The DSA++ is here modified to perform optimal within the fixed wireless access network environment. Therefore, realistic traffic as well as radio channel models for the respective scenarios are introduced. Simulation results are presented, showing the feasibility of the respective protocol stack for offering broadband multimedia services with reasonable quality of service. In addition to this advanced protocol approach, two systems are discussed which are currently under standardisation process. The IEEE 802.16 as well as the European hiperaccess systems are both proposed for fixed wireless access networks. Expected scenarios and applications are presented and basic requirements the standards have to fulfil are derived. As another aspect of access networks, their impact on the global information society is discussed.     

基于图转换的无线接入点关联优化算法

无线接入点关联是 Wi-Fi 系统中的一个基础问题。已有的研究主要集中在考虑带宽容量约束条件下的各种AP关联问题。这些研究没有从用户的角度考虑带宽需求,从用户的带宽需求出发,以最多带宽分配的AP关联为优化目标,考虑混合型网络架构下的Wi-Fi系统的无线接入点关联优化问题。与已有研究方法不同,通过图转换技术,并将问题转化为流图上的优化问题,提出基于网络流的优化求解算法,并从理论上证明算法的最优性。最后,通过对比实验进一步证明了算法的优越性。     

Investigation of wind and rain effects in a foliated tropical region for fixed wireless access

This paper investigates the effects of trees on fixed wireless access operating at 5.8 GHz frequency of the Unlicensed National Information Infrastructure (UNII) band. Measurements are focused on the temporal scale of the received signal strength for a three different links (one line of sight (LOS) link and two non-line of sight (NLOS) link). The statistical characterisation of the combined effects of typical weather phenomena often experienced in a tropical region is presented. As expected, the LOS link is not affected even during heavy rain condition. However, the presence of trees in the vicinity of the transmission path can cause relevant signal deterioration in the case of NLOS link, where the fading of the received signal varies from 2 to 16 dB as the strength of wind and rain increases. Rician distribution can be used to characterise the temporal variation of these weather effects. The work reported in this paper enables the effects of wind, rain and humidity to be properly taken into consideration in the deployment of fixed wireless links in a foliated channel, allowing an optimisation of planning for the end users.     

3.5GHz固定无线接入系统及其在现代通信中的作用

随着信息技术的不断进步和需求的日益增大，全球通信发展的宽带化，无线化，个人化，分组化是大势所趋势，本文就3．5GHz固定无线接入的系统组成，业务类型以及在国际国内的应用等方面进行了论述，认为其可为新运营商低成本地向用户快速，廉价地提供高质量的宽带电信业务，也能为老运营企业做好网络的补充，目前各种技术和运营方式层出不穷，在各种接入技术中，固定无线接入系统具有建网快，见效早，带宽大的优点，在现代通信中占有不可替代的地位。     

Machine learning-based approaches for user association and access point selection in heterogeneous fixed wireless networks

Wireless Networks - Fixed Wireless Networks (FWNs) provide an alternative means for internet connectivity in rural and harsh propagation environments. Intensive technical expertise is therefore...     

异构无线网络混合接入与优化机制

在LTE与WSN异构无线网络架构中,有效降低信道接入时的碰撞概率从而提高网络容量吞吐量是影响异构无线网络性能的关键因素。文中建立混合接入模型及超帧结构,完成时分复用结构下的冲突避免,降低了WSN网络的能量消耗。通过时隙优化机制,解决当接入簇首的LTE UE数量变化频繁时竞争时隙配置不合理所导致的网络资源浪费。仿真结果表明,随着LTE UE的数量的增加,协作机制的性能优于传统的随机竞争接入机制,且协作机制的吞吐量性能呈现线性增长。当接入时隙相对充足簇资源利用趋向饱和时,接入概率和网络吞吐量性能均可保持稳定。     

Broadband fixed wireless access as a key component of the futureintegrated communications environment

It is an exciting time for broadband fixed wireless with key developments in frequency bands from 1 to 60 GHz and a range of new technologies being developed. While working on these new technologies, it is easy to forget that fixed wireless access will form part of an integrated communications environment of the future where users will have one communications device working in the home, at the office, and outdoors. This article predicts the communications environment of the next 20 years and looks at the role of fixed access within that environment. This involves assessing how fixed access systems will interface and integrate with in-home wireless networks, how their architecture will enable multiservice operators to utilize the same core network across a range of different access technologies, and how they will act as a channel to carry mobile traffic originating within the building. Based on the requirements this vision and architecture implies, this article critically assesses the different fixed wireless technologies available to date and compares their capabilities to provide future-proof broadband fixed wireless platforms     

3.5GHz频段固定无线接入系统与固定卫星业务的兼容性分析

根据信息产业部无线电管理局信部无(2000)88号文件要求,3400-3430MHz/3500-3530MHz的2×30MHz的频率拟供FDD方式中的高速无线接入使用.经过技术试验及电磁兼容分析,若证明3.5FGHz频段固定无线接入系统(FWA)系统与卫星C扩展频段有频率共用之可能,并确定了共用条件后,可根据FWA系统的技术发展与市场需求,研究和确定FWA系统如何在3400-3600MHz频段内实现与卫星系统的频率公用.若证明两者之间不可兼容,或为避免相互干扰,FWA系统将于2005年底前退出3400-3600MHz频段.本文将对FWA系统与卫星固定业务的兼容性进行分析.     

WLAN无线接入网络规划及其网络性能优化研究

随着WLAN无线的发展,其覆盖区域、用户量、网络容量不断增加,使其接入网络规划的问题逐渐成为建设公共无线局域网的重要问题.同时,对WLAN无线接入网络性能优化是满足用户需求的关重要手段,网络性能优化主要有覆盖优化、容量优化、设备优化.     

Multiple access protocol for power-controlled wireless access nets

We consider ad hoc wireless networks that are configured as Mobile Backbone Networks. A hierarchical network architecture is synthesized, consisting of Access Nets (ANets) and Backbone Nets (BNets). Each ANet is managed by a (dynamically elected) Backbone Node (BN) that is equipped with higher capability (transmission and processing) modules. The BNs are chosen from currently active mobile backbone-capable nodes or are represented by (ground and/or airborne) unmanned vehicles (UVs) that are guided into selected positions. We develop and investigate a new joint power controlled medium access control (MAC) algorithm for wireless access nets (ANets). Under our new protocol, the net backbone node instructs the ANet nodes to make power control adjustments while simultaneously allocating to them slots for the requested transmissions of their packets. This algorithm, in contrast to other employed conventional graph-based scheduling algorithms, satisfies the requirement that a minimum signal-to-interference and noise ratio (SINR) is met at all intended receivers. We show our algorithm to lead to a significant increase in the net throughput level by attaining high spatial reuse.     

An overview of the standardisation in the area of the broadband fixed wireless access

The broadband fixed wireless access systems will be subject to an increasing development during the next years; these systems will allow to offer the subscriber a full set of services, from the conventional narrow band applications up to the emergent broadband services like Internet access, or leased lines. This rapid growth has carried several initiatives in the telecommunications standardisation bodies, like ETSI in Europe, IEEE in North America, or ITU at international level. These initiatives resulted in the creation of ad hoc groups, for instance the BRAN/Hiperaccess project of ETSI, the IEEE 802.16, or the jrg 8A-9B in ITU standards resulting from this activity are expected in 2000/2001. In parallel to this standardisation activity it appeared necessary to designate, or at least to recommend, dedicated frequency bands for fixed wireless access (fwa) or multimedia wireless systems (mws) applications. In order to satisfy this need the regulation authorities, especially the CEPT in Europe, are preparing decisions and recommendations which are expected to favour a certain level of harmonisation in the use of the spectrum by fwa or mws systems.     

A game theoretic approach to power aware wireless data access

We consider a basic scenario in wireless data access: a number of mobile clients are interested in a set of data items kept at a common server. Each client independently sends requests to inform the server of its desired data items and the server replies with a broadcast channel. We are interested in studying the energy consumption characteristics in such a scenario. First, we define a utility function for quantifying performance. Based on the utility function, we formulate the wireless data access scenario as a noncooperative game - wireless data access (WDA) game. Although our proposed probabilistic data access scheme does not rely on client caching, game theoretical analysis shows that clients do not always need to send requests to the server. Simulation results also indicate that our proposed scheme, compared with a simple always-request one, increases the utility and lifetime of every client while reducing the number of requests sent, with a cost of slightly larger average query delay. We also compare the performance of our proposed scheme with two popular schemes that employ client caching. Our results show that caching-only benefits clients with high query rates at the expense of both shorter lifetime and smaller utility in other clients.     

3.5GHz频段地面固定无线接入系统技术与应用分析

1 3.5GHz无线接入技术分析 固定无线接入网是指业务节点接口(SNI)和用户网络接口(UNI)之间的传送实体由无线链路来实现的接入方式,远端站不可移动使用.     

Co-channel interference effects as applied to broadband fixed wireless access channel capacity statistical distribution

Channel Capacity is of primary importance in broadband fixed wireless access (bfwa) networks due to the ever increasing demand for multimedia services and the possibility of providing wireless Internet. One of the major factors limiting capacity in such systems is interference originating from adjacent terrestrial applications belonging to the same bfwa network or to another. Moreover, the performance of broadband fixed wireless access links operating above 10 GHz is predominantly controlled by rain attenuation. The purpose of this paper is the presentation of a physical model for the evaluation of the fraction of the time where the capacity distribution of a broadband fixed wireless access channel under rain fade conditions suffering from co-channel interference, non-exceeds a specified level in (bps/Hz). The proposed analysis examines the capacity distribution properties focusing on the spatial inhomogeneity of rainfall medium. The impact of various operational and geometrical parameters on the performance of interfered broadband wireless access channel capacity distribution is investigated through extended simulations.