高空平台站(HAPS)获得新增频谱资源划分

HAPS是指位于距离地面18到50公里的空中通信平台站。它相对于地球准静止,具有通信范围大、时延低等特点,能够为偏远地区和恶劣地形条件下的地区建设关口站或开展大容量通信服务提供便捷、经济的解决方案。特别是在地震、洪水等严重自然灾害导致常规通信系统瘫痪时,HAPS还能够快速地提供有效应急通信服务。2019年世界无线电通信大会(WRC-19)通过审议1.14议题"促进人们获取通过高空平台台站提供的宽带应用"并作出决议,在全球范围内,在固定业务划分下新增38GHz^39.5GHz频段,扩展31GHz^31.3GHz频段标识用于高空平台站(HAPS)固定通信(双向使用),在满足H A P S应用需求的同时,对H A P S下行方向使用提出了具体限制以保护现有的固定、移动和卫星固定业务台站不受影响。     

高空平台不稳定性对HAPS通信性能影响建模与分析

 由于高空平台不可能静止驻留在空中,平台打转、摇摆等状态就会对HAPS(High Altitude Platform Stations)通信性能产生关键影响.目前的研究都处在假设平台稳定或调整波束指向能够补偿由于高空平台移动造成的剩余指向误差,存在很大的局限性,不能真实反应实际情况.本文通过建模把平台的不稳定性带来的影响反应到无线链路上,解决平台不稳定性等造成收发信号随机变化大而无法通信或通信质量差的问题.并通过仿真分析验证本文提出模型的正确性.     

一种基于距离判决的HAPS通信无线DCA算法

本文提出一种基于距离判决的高空平台站(HAPS)通信的动态信道分配(DCA)算法,通过对无线链路功率到收发链路距离的转化,实时监测HAPS通信的收发链路距离来进行无线信道分配,解决HAPS通信中由于负载不均等造成的无线资源无法满足用户需求的问题.通过与随机信道分配算法及最差可接受信道分配算法的性能进行比较,本文提出的基于距离判决的算法能够在阻塞概率稍微增加的情况下解决系统连接中断问题,有效地提高了系统的整体性能.     

高空平台信息系统--新一代无线通信体系(下)

高空平台站(HAPS)是近年来正处于先期研究、但尚未成功演示的新型信息系统。它利用平流层稳定的气象条件和良好的电波传输特性,通过平台实现地面用户之间、平台之间或平台与卫星之间的通信连接,具有布局灵活、应用广泛、成本低廉、安全可靠等优点。积极开展高空平台与有关信息系统的研究,有助于我国在通信事业上与国际先进技术保持同步,为通信事业开拓一个新的领域。     

高空平台信息系统--新一代无线通信体系(上)

高空平台站(HAPS)是近年来正处于先期研究、但尚未成功演示的新型信息系统。它利用平流层稳定的气象条件和良好的电波传输特性,通过平台实现地面用户之间、平台之间或平台与卫星之间的通信连接,具有布局灵活、应用广泛、成本低廉、安全可靠等优点。积极开展高空平台与有关信息系统的研究,有助于我国在通信事业上与国际先进技术保持同步,为通信事业开拓一个新的领域。     

高空平台（HAPS）中继通信系统——一种新型无线通信系统

高空平台(HAPS：High Attitude Platform Station)系统利用距地面20km至50km的高空平台作为基站来提供电信业务和广播业务，它的出现是为了降低卫星通信系统和地面通信系统的昂贵花费，同时也考虑到了减小对人体的电磁辐射。理论上来说，和卫星通信系统相比，它具有高容量(1000倍bps／km^2)、高频谱利用率、时延小、易维护、易升级、可迅速建设等优点；     

HAPS通信在低仰角区的性能分析

高空平台站HAPS(high altitude platform station)通信根据地面天线仰角的不同,划分为高仰角区(≥30°)、中仰角区(10°≤θ≤30°)和低仰角区(θ≤10°)。在高、中仰角区域,电波传播基本为恒参信道,可以按照一般微波链路进行分析;在低仰角区,由于地形、建筑、植被等的反射,以及升空平台本身的随机摆动与反射,造成地面接收电平严重衰落,由恒参信道逐渐变为莱斯(Ricean)信道。就莱斯信道下,如何实现大容量HAPS通信的稳定工作进行了分析。     

WRC-19结论分析及启示

频谱资源是移动通信产业发展的关键资源,世界无线电大会(WRC)作为ITU终极政策法规制定的权威机构,深刻影响移动通信产业的长期发展战略。2019年世界无线电通信大会(WRC-19)就5G毫米波频段、太赫兹地面通信频段的划分和高空平台通信(HAPS)新增使用频段等议题达成共识,同时确定了WRC-23的议题研究方向。根据WRC-19 IMT议题的结论,以及WRC-23IMT相关议题的研究内容及目标,结合IMT产业未来发展需求,提出了国内频率规划及研究的建议。     

准静止状态下的高空平台实时业务信道分配

受平台准静止状态的影响,高空平台（ HAPS)通信网络内存在大量的切换呼叫,且业务量动态变化。 HAPS网络可传输多种业务,其中实时业务在切换过程中具有较高的时延要求。通过为切换呼叫预留信道可降低平台不稳定对服务质量（ QoS)造成的影响。在基于服务优先级的多业务信道分配算法基础上,重点对实时业务的信道分配算法进行改进,提出了一种基于概率的预留信道借用策略。该算法可根据网络内业务量的实时统计数据控制新呼叫业务的准入。仿真结果表明：与固定预留信道算法和门限预留信道算法相比,该算法能够适应网络内业务量的动态变化,在保证切换呼叫掉线率满足期望值的条件下提升系统的整体性能,降低平台不稳定造成的性能损失。     

高频通信技术

毫米波是第5代移动通信系统的重要通信技术,利用大带宽承载大量信息,有效提升系统的吞吐量。第3代合作伙伴计划(3GPP)已经对毫米波频段做了划分,各个国家逐步对频谱进行分配。毫米波因其频谱特性,需要与大规模天线阵列结合使用,获得波束赋形增益。通过对波束设计与波束管理等核心技术的创新,实现热点高速传输。同时,通过高低频无线协作组网的方式,实现整个区域内的基础覆盖,以适应不同的通信场景需求。     

Capacity of the WCDMA System Using High Altitude Platform Stations

In this paper, we provide a method to estimate the capacity of the wideband code division multiple access (WCDMA) scheme using High Altitude Platform Stations (HAPS), and demonstrate the results. This is to validate that the HAPS system is one of the most effective solutions to provide high quality wireless communication services, such as IMT-2000 services. We use a practical system model which describes the HAPS system most appropriately, and this leads to realistic estimation results. We estimate the reverse and forward link capacity of the HAPS WCDMA system and compare it to that of the terrestrial system. The estimation results show that the capacity of the HAPS WCDMA system is about 1.2–1.67 times larger than that of the terrestrial system.     

高速铁路场景下环境反向散射辅助的无线传输方案

将反向散射技术引入到高铁场景的无线通信系统中,提出一种反向散射辅助无线传输方案（Backscatter Aided Wireless Transmission,BAWT）,并针对BAWT和传统无线传输方案（Direct Wireless Transmission,DWT）进行了收发信机设计,包括信道估计以及信号检测。与传统无线传输方案相比,证明了在固定的火车天线和不变的轨道情况下,BAWT可以获得信道统计信息为信道估计提供助力。通过仿真对比两种方案的信道估计均方误差,BAWT方案相较DWT方案的信道估计准确性明显提高;对比BAWT、传统中继技术以及DWT方案,当信噪比为20 dB时,对应的BAWT方案和中继技术、DWT方案的误码率分别为1%和2%和12%,BAWT方案误码检测性能获得明显提升。此外,针对广域环境下的环境反向散射通信,推导了高铁场景下使用蜂窝移动通信信号作为RF信源的无线链路预算,反向散射信号在车厢内的覆盖范围内可以满足接收机的灵敏度要求,从链路预算角度论证了BAWT方案实现的可行性。     

Modeling frame synchronization for UMTS high-speed downlink packet access

Third Generation Partnership Project (3GPP) specification TR 25.950 proposed high-speed downlink packet access for the Universal Mobile Telecommunication System (UMTS). In this mechanism, an active set of cells is defined for every user equipment (UE) communication session. The cell with the best wireless link quality (called the serving cell) in the active set is selected for communication with the UE. When the wireless link quality of the old serving cell degrades below some threshold, a new serving cell in the active set is selected to continue the communication session. Our previous work proposed a high-speed downlink packet access (HSDPA) overflow control scheme with four frame synchronization algorithms to switch the serving cell, and formally proved the correctness of the scheme. We propose an analytic model to investigate the performance of these frame synchronization algorithms, and show how the user movement patterns affect the control message delivery costs of these algorithms.     

Impact of antenna and beam-selection-based sectored relay planning for performance evaluation of 4G LTE-A tri-sectored cell

The deployment of Relay Nodes (RNs) in 4G LTE-A networks, mainly originating from the wireless backhaul link, provides an excellent network planning tool to enhance system performance. Better coordination between the base station and relays to mitigate inter-cell interference becomes an important aspect of achieving the required system performance, not only in the single-cell scenario, but also in multi-cell scenarios. In this paper, we model and analyze two basic approaches for designing a 4G LTE-A tri-sectored cellular system. The approaches are based on Antenna Selection Sectored Relaying (ASSR) and Beam Selection Sectored Relaying (BSSR). The main purpose of the proposed schemes is to enhance system performance by improving the quality of the wireless relay backhaul link. In this technique, antenna selection takes into consideration Non-Line-Of-Sight (NLOS) communication, whereas BSSR considers the case of Line-Of-Sight (LOS) communication using heuristic beam forming approach. The resource allocation problem has also been investigated for relay based cooperative LTE-A tri-sectored cell in the downlink. The best possible location for relay node in the sector, power allocation and MIMO channel modeling is formulated as an optimization problem with the aim of maximizing the end to end link rate and the Signal to Interference plus Noise Ratio (SINR) of 4G LTE-A systems. Power allocation/optimization has been solved by means of the duality equation of the stationary Karush-Kuhn-Tucker (KKT) condition and is used to derive optimal values for the beam forming vector on both the relay as well as the access link. The performance of the proposed scheme is verified through simulations carried out using MATLAB software. The simulation results show a significant improvement in the SINR, throughput capacity, and coverage area of the 4G LTE-A cell, while guaranteeing better quality of service.     

有线无线融合的卫星时间敏感网络流调度研究

随着空间通信任务日趋复杂化,尤其是对时间敏感的需求不断提升,一方面要求星内系统的高带宽、可靠性和实时性;另一方面星间无线链路也应具备低时延和高可靠性.但由于卫星内部有线链路与星间无线链路差异大,业务数据经过有线和无线链路联合传输时,容易引发节点拥塞,而无法保障时敏业务的时延有界需求.为了提升数据在空间网络传输的实时性,...     

Locating strategies for personal communication networks, a noveltracking strategy

The partition of location areas is designed to minimize the total costs of finding users' location and tracking their movement in personal communication networks (PCNs). A new scheme to partition and track mobile users and its implementation based on cellular architecture are proposed. According to the tracking strategy, the mobile station (MS) transmits only update messages at specific reporting cells, while the search for a mobile user is done at the vicinity of the cell to which the user has just reported. We use the cost analysis model to demonstrate the feasibility of updating and searching costs to reduce the amount of resources when using wireless channels. Simulations are performed to compare the performance of three schemes: always update, always search, and our new scheme     

基于相位补偿的非理想无线轨道角动量复用通信系统研究

电磁波轨道角动量各模态间满足严格正交性,为无线通信系统提供了一个新的复用维度。当前无线轨道角动量通信的研究仍集中于理想视距(LoS)场景,在实际通信场景中,多径效应和非对齐效应等非理想传输情况通常是无法避免的,这会使得无线轨道角动量多入多出(OAM-MIMO)通信系统的性能遭受较大损失。为提升非理想无线OAM-MIMO通信系统性能,该文建模了一种更加符合实际传输场景的毫米波OAM-MIMO 10射线信道模型;然后评估了多径效应和非对齐效应带来的性能损失问题;最后,提出了一种低复杂度的平均相位补偿与迭代功率分配(APC-IPA)联合优化方案来消除非对齐和多径效应造成的相位偏差,提升系统信道容量。仿真结果表明：在同时遭受非对齐和多径效应时,所提APC-IPA联合方案能够有效地提升系统信道容量。     

Transmission delay minimization in wireless powered communication systems

Wireless Networks - We study transmission delay minimization of a wireless powered communication (WPC) system in a point-to-point scenario with one hybrid access point (HAP) and one WPC node. In...