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5G High Mobility Wireless Communications: Challenges and Solutions 被引量:18
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作者 pingzhi fan Jing Zhao Chih-Lin I 《China Communications》 SCIE CSCD 2016年第S2期1-13,共13页
The fifth generation(5G) network is expected to support significantly large amount of mobile data traffic and huge number of wireless connections,to achieve better spectrum- and energy-efficiency,as well as quality of... The fifth generation(5G) network is expected to support significantly large amount of mobile data traffic and huge number of wireless connections,to achieve better spectrum- and energy-efficiency,as well as quality of service(QoS) in terms of delay,reliability and security.Furthermore,the 5G network shall also incorporate high mobility requirements as an integral part,providing satisfactory service to users travelling at a speed up to 500 km/h.This paper provides a survey of potential high mobility wireless communication(HMWC) techniques for 5G network.After discussing the typical requirements and challenges of HMWC,key techniques to cope with the challenges are reviewed,including transmission techniques under the fast timevarying channels,network architecture with mobility support,and mobility management.Finally,future research directions on 5G high mobility communications are given. 展开更多
关键词 5G high mobility wireless communications fast time-varying channel network architecture mobility management
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New Delay Doppler Communication Paradigm in 6G Era:A Survey of Orthogonal Time Frequency Space(OTFS) 被引量:3
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作者 Weijie Yuan Shuangyang Li +4 位作者 Zhiqiang Wei Yuanhao Cui Jiamo Jiang Haijun Zhang pingzhi fan 《China Communications》 SCIE CSCD 2023年第6期1-25,共25页
In the 6G era,Space-Air-Ground Integrated Network(SAGIN)are anticipated to deliver global coverage,necessitating support for a diverse array of emerging applications in high-mobility,hostile environments.Under such co... In the 6G era,Space-Air-Ground Integrated Network(SAGIN)are anticipated to deliver global coverage,necessitating support for a diverse array of emerging applications in high-mobility,hostile environments.Under such conditions,conventional orthogonal frequency division multiplexing(OFDM)modulation,widely employed in cellular and Wi-Fi communication systems,experiences performance degradation due to significant Doppler shifts.To overcome this obstacle,a novel twodimensional(2D)modulation approach,namely orthogonal time frequency space(OTFS),has emerged as a key enabler for future high-mobility use cases.Distinctively,OTFS modulates information within the delay-Doppler(DD)domain,as opposed to the timefrequency(TF)domain utilized by OFDM.This offers advantages such as Doppler and delay resilience,reduced signaling latency,a lower peak-to-average ratio(PAPR),and a reduced-complexity implementation.Recent studies further indicate that the direct interplay between information and the physical world in the DD domain positions OTFS as a promising waveform for achieving integrated sensing and communications(ISAC).In this article,we present an in-depth review of OTFS technology in the context of the 6G era,encompassing fundamentals,recent advancements,and future directions.Our objective is to provide a helpful resource for researchers engaged in the field of OTFS. 展开更多
关键词 OTFS 6G delay-Doppler(DD)domain
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低渗透油藏CO_(2)驱前缘移动规律及主控因素研究 被引量:1
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作者 毛振强 高同 +2 位作者 董平志 樊超 刘赛军 《科学技术创新》 2023年第11期47-53,共7页
低渗透油藏CO_(2)驱替可以大幅度提高开发效果,但是CO_(2)气窜严重,CO_(2)气水交替可以降低气窜现象。为了治理气窜,提出了混相压力前缘、组分前缘和CO_(2)相前缘的概念,建立典型井组概念模型,刻画了三个前缘的运行特征和影响因素。研... 低渗透油藏CO_(2)驱替可以大幅度提高开发效果,但是CO_(2)气窜严重,CO_(2)气水交替可以降低气窜现象。为了治理气窜,提出了混相压力前缘、组分前缘和CO_(2)相前缘的概念,建立典型井组概念模型,刻画了三个前缘的运行特征和影响因素。研究表明,随着注入井的不断注入,三个前缘的半径都在逐渐的扩大,但混相压力前缘相比于气相前缘和组分前缘传播速度更快。影响前缘的主要敏感因素有地层渗透率、注入速度、压力保持水平等参数,其中压力前缘主要受到地层渗透率和流体物性影响,组分前缘主要受到扩散系数水平影响,相前缘主要受到注入速度影响。该研究对低渗透油藏CO_(2)驱油的高效开发提供了一定的技术指导。 展开更多
关键词 CO_(2)驱 数值模拟 气水交替驱 驱替前缘
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Orthogonal Time Frequency Space Modulation in 6G Era
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作者 Weijie Yuan Zhiqing Wei +3 位作者 Jiamo Jiang Shun Zhang Jinhong Yuan pingzhi fan 《China Communications》 SCIE CSCD 2023年第1期I0002-I0005,共4页
Over the past decades, wireless technologies with reliable data transmissions and precise sensing ability in hostile environments are much less understood and significantly under-developed. The DD domain waveform, e.g... Over the past decades, wireless technologies with reliable data transmissions and precise sensing ability in hostile environments are much less understood and significantly under-developed. The DD domain waveform, e.g., orthogonal time frequency space(OTFS), has been recognized globally for its great potential to achieve high-reliable communications and robust sensing performance under various channel conditions in 6G era. 展开更多
关键词 WIRELESS globally PRECISE
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不同授粉品种对沙田柚果实品质的影响
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作者 张瑞敏 吴平治 +4 位作者 樊正炎 朱从一 黄永敬 张曼 曾继吾 《现代食品》 2023年第21期193-196,共4页
沙田柚具有自花授粉亲和性差,单一品种种植产量低的特点。因此,生产上常在沙田柚果园内配置一定比例的其他柚类品种作为授粉树。本试验在盛花期分别将蜜柚、水晶柚、梅花早、暹罗柚和酸柚的花粉授到沙田柚柱头上,研究不同授粉品种对沙... 沙田柚具有自花授粉亲和性差,单一品种种植产量低的特点。因此,生产上常在沙田柚果园内配置一定比例的其他柚类品种作为授粉树。本试验在盛花期分别将蜜柚、水晶柚、梅花早、暹罗柚和酸柚的花粉授到沙田柚柱头上,研究不同授粉品种对沙田柚果实品质的影响。结果表明,异花授粉会明显影响沙田柚的外观品质,异花授粉后的果实颈长均显著缩短,单果重均显著增加。与自然授粉相比,授酸柚花粉的果实横径显著增加;授梅花早花粉的果实果皮显著变薄。同时,异花授粉对沙田柚果实内在品质影响较大,除对照外,授水晶柚花粉的果实中的维生素C含量、可溶性糖含量、可溶性固形物含量以及糖酸比都较好。对比分析发现,水晶柚是沙田柚最优的授粉品种,授粉后果实综合品质好。 展开更多
关键词 沙田柚 授粉 果实品质 花粉直感
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Position-assisted fast handover schemes for LTE-advanced network under high mobility scenarios 被引量:4
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作者 Ming FEI pingzhi fan 《Journal of Modern Transportation》 2012年第4期268-273,共6页
Two position-assisted fast handover schemes, scheme A and scheme B, for LTE-A system under very high mobility scenarios, are proposed, together with their performance evaluation. Scheme A is designed to reduce handove... Two position-assisted fast handover schemes, scheme A and scheme B, for LTE-A system under very high mobility scenarios, are proposed, together with their performance evaluation. Scheme A is designed to reduce handover delay by making handover preparation before handover starts. Scheme B aims at reducing unnecessary handovers and improving handover success rate, by calculating the geographically best target handover cell, which makes it easier for mobile terminals to access the target cell. A system level simulation is conducted to evaluate the performance of these two schemes. It is shown that, scheme A could reduce inter-site handover delay by about 50 ms, while scheme B could cut down nearly 50% of all handovers when time-to-trigger (TTT) is 0 ms. Besides, as TTT gets larger, Scheme B has much better success rate. 展开更多
关键词 LTE-A HANDOVER very high mobility handover delay handover frequency handover success rate
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一种基于中继的车辆编队功率优化算法 被引量:2
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作者 胡杰文 马征 +2 位作者 刘刚 范平志 唐优华 《中国科学:信息科学》 CSCD 北大核心 2022年第7期1317-1332,共16页
车辆编队作为蜂窝车联网(cellular-vehicle-to-everything, C-V2X)的高级应用之一,可以有效地提高出行效率.处于编队内的车辆需要实时共享速度、前进方向和意图(制动、加速度等)等信息,并且位于队头的车辆需负责整个编队的管理并传递控... 车辆编队作为蜂窝车联网(cellular-vehicle-to-everything, C-V2X)的高级应用之一,可以有效地提高出行效率.处于编队内的车辆需要实时共享速度、前进方向和意图(制动、加速度等)等信息,并且位于队头的车辆需负责整个编队的管理并传递控制消息.但是在高密度场景下,当多个编队的队头被分配到同一子信道上同时传输时,多个编队之间会存在干扰,如果队头车辆以传统的固定功率方式进行广播,广播功率过大会导致对其他队列造成的干扰过大,广播功率过小则会影响队列内成员的接收质量,因此需要合适的功率分配方案以满足高密度场景下的通信需求.本文在满足时延、接收信噪比要求的前提下以最小化总功率消耗为目标,提出了一种基于中继的多队列协作功率优化方案,该方案通过在编队内选取合适的中继车辆以减少每跳广播所需要的功率,从而减少对其他编队的干扰并且降低总功率消耗.仿真结果表明,所提出的方案相比传统方案能够容纳更多的编队成员,并且在满足性能要求的前提下大幅降低总功率消耗. 展开更多
关键词 C-V2X 车辆编队 广播功率 中继 功率优化
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A Multi-Hop Moving Zone(MMZ) Clustering Scheme Based on Cellular-V2X 被引量:3
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作者 Zahid Khan pingzhi fan 《China Communications》 SCIE CSCD 2018年第7期55-66,共12页
A clustering scheme based on pure V2V communications has two prominent issues i.e. broadcast storm and network disconnection. The application of the fifth generation(5G) technology to vehicular networks is an optimal ... A clustering scheme based on pure V2V communications has two prominent issues i.e. broadcast storm and network disconnection. The application of the fifth generation(5G) technology to vehicular networks is an optimal choice due to its wide coverage and low latency features. In this paper, a Multihop Moving Zone(MMZ) clustering scheme is proposed by combining IEEE 802.11p with the 3rd Generation Partnership Project(3GPP) 5G cellular technology. In MMZ, vehicles are clustered up-to three hops using V2V communications based on IEEE 802.11 p aiming to reduce excessive cellular hand-off cost. While the zonal heads(ZHs) i.e. cluster heads(CHs) are selected by cellular-V2X(C-V2X) on the basis of multi-metrics i.e. relative speed, distance and link life time(LLT). The main goal of MMZ is to form stable clusters achieving high packet delivery and low latency. The simulation results using ns3 show that, 5G wide range technology significantly improves the stability of MMZ in term of ZH duration and change rate. The average Data Packet Delivery Ratio(DPDR) and E2E latency are also improved as compared to the existing clustering schemes. 展开更多
关键词 clustering 3GPP 5G cluster head stable clusters reliability and latency
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Active User and Data Detection for Uplink Grant-free NOMA Systems 被引量:2
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作者 Donghong Cai Jinming Wen +3 位作者 pingzhi fan Yanqing Xu Lisu Yu 《China Communications》 SCIE CSCD 2020年第11期12-28,共17页
This paper proposes some low complexity algorithms for active user detection(AUD),channel estimation(CE)and multi-user detection(MUD)in uplink non-orthogonal multiple access(NOMA)systems,including single-carrier and m... This paper proposes some low complexity algorithms for active user detection(AUD),channel estimation(CE)and multi-user detection(MUD)in uplink non-orthogonal multiple access(NOMA)systems,including single-carrier and multi-carrier cases.In particular,we first propose a novel algorithm to estimate the active users and the channels for single-carrier based on complex alternating direction method of multipliers(ADMM),where fast decaying feature of non-zero components in sparse signal is considered.More importantly,the reliable estimated information is used for AUD,and the unreliable information will be further handled based on estimated symbol energy and total accurate or approximate number of active users.Then,the proposed algorithm for AUD in single-carrier model can be extended to multi-carrier case by exploiting the block sparse structure.Besides,we propose a low complexity MUD detection algorithm based on alternating minimization to estimate the active users’data,which avoids the Hessian matrix inverse.The convergence and the complexity of proposed algorithms are analyzed and discussed finally.Simulation results show that the proposed algorithms have better performance in terms of AUD,CE and MUD.Moreover,we can detect active users perfectly for multi-carrier NOMA system. 展开更多
关键词 non-orthogonal multiple access massive connection active user detection channel estimation multi-user detection and alternating direction method of multipliers
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Advances in broadband wireless communications under high-mobility scenarios 被引量:2
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作者 pingzhi fan 《Chinese Science Bulletin》 SCIE EI CAS 2014年第35期4974-4975,共2页
未来活动通讯系统瞄准提供很高的数据传播率,甚至在象高速度的车轮轨道火车,磁悬浮火车火车,高速公路车辆,飞机,指导导弹或太空船那样的高活动性的情形。一个特别地重要的商业应用程序是对高速度的宽带的强壮、增加的世界范围的要... 未来活动通讯系统瞄准提供很高的数据传播率,甚至在象高速度的车轮轨道火车,磁悬浮火车火车,高速公路车辆,飞机,指导导弹或太空船那样的高活动性的情形。一个特别地重要的商业应用程序是对高速度的宽带的强壮、增加的世界范围的要求无线通讯(多达 574.8 ? km/h 测试速度或 380 ? km/h 广告速度)为象为旅客的机载的娱乐服务那样的应用程序在铁路,提供的数据,声音和录像满足,火车控制,训练派遣,火车传感器地位处理和监视。在如此的高活动性的情形,有很多通讯挑战,包括快移交,更新的地点,当模特儿的高速度的隧道,评价和均等, anti-Doppler 传播技术,快力量控制,和奉献网络建筑学。因为在很高速度的情形的信号传播将不可避免地经历 s …… 展开更多
关键词 宽带无线通信 高流动性 高速轮轨列车 场景 数据传输速率 移动通信系统 商业应用 移动通讯技术
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Guest editorial: special issue on high mobility wireless communications 被引量:2
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作者 pingzhi fan Erdal PANAYIRCI +2 位作者 Ping LI Chengxiang WANG Vahid TAROKH 《Journal of Modern Transportation》 2012年第4期197-198,共2页
The high-speed railway and high-way networks are now expanding at a phenomenal speed in Chinaand in many other parts of the world. The related broadband wireless communication over high-speed trains and highway vehicl... The high-speed railway and high-way networks are now expanding at a phenomenal speed in Chinaand in many other parts of the world. The related broadband wireless communication over high-speed trains and highway vehicles is a very challenging task due to hostile transmission channel conditions. The demand for such services is growing rapidly, following the proliferation of laptop/tablet computers and smart phones. This motivates the research on wireless communications in the high mobility environments. 展开更多
关键词 high mobility wireless communications high speed trains (HSTs)
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Coping with the Big Data:Convergence of Communications,Computing and Storage 被引量:2
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作者 pingzhi fan 《China Communications》 SCIE CSCD 2016年第9期203-207,共5页
To cope with the impact of big data,it is proposed to integrate the traditionally individual computing,communications and storage systems,which are getting inevitably converged.An effective information system capacity... To cope with the impact of big data,it is proposed to integrate the traditionally individual computing,communications and storage systems,which are getting inevitably converged.An effective information system capacity is introduced and discussed,aimed at excavating potentials of information system under a new paradigm with more degrees of freedom. 展开更多
关键词 big data COMMUNICATIONS com- puting STORAGE information system capacity
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不同定根水施用量对烤烟生长发育及产量的影响
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作者 王树林 曲平治 +2 位作者 范静苑 杨博凯 向盼来 《现代农业科技》 2022年第22期1-4,10,共5页
采用田间试验方法,以烤烟品种K326为试验材料,研究了不同定根水用量对烤烟生长发育、外观质量、化学成分及感官质量的影响,以期筛选出通海烟区适宜的定根水使用量。结果表明,适当增加定根水用量,可以促进烟株生长发育,还苗时间提前3~4 d... 采用田间试验方法,以烤烟品种K326为试验材料,研究了不同定根水用量对烤烟生长发育、外观质量、化学成分及感官质量的影响,以期筛选出通海烟区适宜的定根水使用量。结果表明,适当增加定根水用量,可以促进烟株生长发育,还苗时间提前3~4 d,降低了病虫害发病率和病情指数。同时,随着定根水用量的增加,烟叶外观质量、化学成分协调性及经济效益呈现先提高后降低的趋势。综合分析认为,定根水用量2 kg/株的经济效益较高,化学成分协调性较好,清香型特征明显,综合表现较好。 展开更多
关键词 烤烟 定根水 生长发育 外观质量 感官质量
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Polar Coded Iterative Multiuser Detection for Sparse Code Multiple Access System 被引量:1
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作者 Hang MU Youhua Tang +3 位作者 Li Li Zheng Ma pingzhi fan Weiqiang Xu 《China Communications》 SCIE CSCD 2018年第11期51-61,共11页
Polar coded sparse code multiple access(SCMA) system is conceived in this paper. A simple but new iterative multiuser detection framework is proposed, which consists of a message passing algorithm(MPA) based multiuser... Polar coded sparse code multiple access(SCMA) system is conceived in this paper. A simple but new iterative multiuser detection framework is proposed, which consists of a message passing algorithm(MPA) based multiuser detector and a soft-input soft-output(SISO) successive cancellation(SC) polar decoder. In particular, the SISO polar decoding process is realized by a specifically designed soft re-encoder, which is concatenated to the original SC decoder. This soft re-encoder is capable of reconstructing the soft information of the entire polar codeword based on previously detected log-likelihood ratios(LLRs) of information bits. Benefiting from the soft re-encoding algorithm, the resultant iterative detection strategy is able to obtain a salient coding gain. Our simulation results demonstrate that significant improvement in error performance is achieved by the proposed polar-coded SCMA in additive white Gaussian noise(AWGN) channels, where the performance of the conventional SISO belief propagation(BP) polar decoder aided SCMA, the turbo coded SCMA and the low-density parity-check(LDPC) coded SCMA are employed as benchmarks. 展开更多
关键词 iterative multiuser receiver polarcode sparse code multiple access (SCMA)
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A Priority Queuing Model for HCF Controlled Channel Access (HCCA) in Wireless LANs
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作者 Reza GHAZIZADEH pingzhi fan Yi PAN 《International Journal of Communications, Network and System Sciences》 2009年第1期30-43,共14页
Recently, there has been a rapid growing interest in new applications requiring quality of service (QoS) guarantees through wireless local area networks (WLAN). These demands have led to the introduction of new 802.11... Recently, there has been a rapid growing interest in new applications requiring quality of service (QoS) guarantees through wireless local area networks (WLAN). These demands have led to the introduction of new 802.11 standard series to enhance access medium supporting QoS for multimedia applications. However, some applications such as variable bit rate (VBR) traffic address some challenges in the hybrid coordination function (HCF) nominated to provide QoS. This paper presents a novel priority queuing model to analyze a medium access in the HCF controlled channel access (HCCA) mode. This model makes use of a MAP (Markovian Arrival Process)/PH (Phase Type)/1 queue with two types of jobs which are suitable to support VBR traffic. Using a MAP for traffic arrival process and PH distribution for service process, the inclusion of vacation period makes our analysis very general and comprehensive to support various types of practical traffic streams. The proposed priority queuing model is very useful to evaluate and enhance the performance of the scheduler and the admission controller in the HCCA mechanism. 展开更多
关键词 QoS HCCA PRIORITY QUEUES Matrix-Geometric Method MAP/PH/1
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Modified clustered comb pilot-aided fast time-varying channel estimation for OFDM system
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作者 Xin LI pingzhi fan 《Journal of Modern Transportation》 2012年第4期220-226,共7页
As high-speed railway is booming worldwide, the communication system with fast-time varying channel has drawn great attention. The comb pilot based linear minimum mean square error (LMMSE) channel estimator is prove... As high-speed railway is booming worldwide, the communication system with fast-time varying channel has drawn great attention. The comb pilot based linear minimum mean square error (LMMSE) channel estimator is proved to be an effective method for fast time-varying channel estimation. In this paper, the clustered comb pilot-aided chan- nel estimation for orthogonal frequency-division multiplexing (OFDM) system is discussed, where the time varying channel is approximated by a basis expansion model (BEM). A modified clustered comb pilot structure is proposed and justified to improve the estimation performance compared with the clustered comb pilot proposed by Tang. Based on the complex-exponential BEM (CE-BEM) model, a suboptimal-pilot structure is proposed. In addition, optimal pilot length is analyzed and simulated with a predefined total number of pilots. The simulation results show that the modi- fied clustered comb pilot can greatly reduce the estimation error especially with high Doppler spread. The suboptimal- pilot structure with guard pilot approximation is proven to be competitive. Optimal nonzero pilot lengths for different Doppler spread are obtained by simulation with a predefined channel order and fixed pilot subcarriers. 展开更多
关键词 OFDM LMMSE BEM clustered comb pilot high mobility
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Asymptotic analysis of multi-branch two-way amplify-and-forward relaying in Nakagami-m fading with arbitrary fading parameter
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作者 Jing YANG pingzhi fan 《Journal of Modern Transportation》 2012年第4期249-254,共6页
Two-way relay networks have received lots of attention, thanks to its ability to overcome the loss in the spectral efficiency due to half-duplex transmission. Asymptotic performance analysis can provide valuable insig... Two-way relay networks have received lots of attention, thanks to its ability to overcome the loss in the spectral efficiency due to half-duplex transmission. Asymptotic performance analysis can provide valuable insights in- to practical system designs. However, this is a gap in two-way relay network. In this paper, the asymptotic performance is studied for multi-branch dual-hop two-way amplify-and-forward (AF) relaying networks in independently but not necessarily identically distributed (i.n.i.d.) Nakagami-m fading channels, with arbitrary m 〉 5. The approximate prob- ability density function (PDF) of the instantaneous dual-hop link power at high SNR region is derived. Then we present the asymptotic outage probability expression, and analyze the diversity order and coding gain. Simulations are per- formed to verify the tightness of the presented analysis at medium and high SNR regions. 展开更多
关键词 two-way relay network AMPLIFY-AND-FORWARD outage probability average bit error probability Nakagami-m fading
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Optimal power allocation for complex field network coding scheme with the K-th best relay selection
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作者 Xi CAI pingzhi fan Qingchun CHEN 《Journal of Modern Transportation》 2012年第4期255-260,共6页
Wireless relay and network coding are two critical techniques to increase the reliability and throughput of wireless cooperative communication systems. In this paper, a complex field network coding (CFNC) scheme wit... Wireless relay and network coding are two critical techniques to increase the reliability and throughput of wireless cooperative communication systems. In this paper, a complex field network coding (CFNC) scheme with the K-th best relay selection (KBS) is proposed and investigated, wherein the K-th best relay is selected to forward the multiplexed signal to the destination. First, the upper bound of the symbol error probability (SEP), the diversity order, and the coding gain are derived for the CFNC scheme with KBS. Then, the coding gain is utilized as the optimized cri- terion to determine the optimal power allocation. It is validated through analysis and simulation that the CFNC scheme with KBS can achieve full diversity only when K=I, while the diversity order decreases with increasing parameter K, and the optimal power allocation can significantly improve the performance of the CFNC scheme with KBS. 展开更多
关键词 complex field network coding the K-th best relay selection power allocation
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