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浅谈提高信道效率的措施
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作者 魏彤 初晓梅 《信息技术》 2002年第3期19-20,共2页
提高信道的数据传输效率是人们不断追求的目标之一 ,也是衡量网络性能的标准之一 。
关键词 信道效率 调制技术 数据交换技术 数据传输
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无线家庭网络MAC层信道传输效率分析 被引量:1
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作者 于珏 吴韶波 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2007年第5期753-756,共4页
在深入研究Ad Hoc技术和家庭网络的基础上,找出二者的结合点,提出一种基于Ad Hoc技术的无线家庭网络以及该网络的分层模型,根据无线家庭网络的特点,对分层模型中的MAC层信道利用率进行了重点讨论.结果表明,基于CSMA/CA机制的MAC层实现简... 在深入研究Ad Hoc技术和家庭网络的基础上,找出二者的结合点,提出一种基于Ad Hoc技术的无线家庭网络以及该网络的分层模型,根据无线家庭网络的特点,对分层模型中的MAC层信道利用率进行了重点讨论.结果表明,基于CSMA/CA机制的MAC层实现简单,成本较低,且支持多跳,市场前景广阔. 展开更多
关键词 AD HOC 家庭网络 信道传输效率
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无线局域网MAC层信道利用效率分析 被引量:4
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作者 江连山 陈伟萍 《现代电子技术》 2006年第7期4-6,共3页
基于IEEE802·11g的WLAN的标称速率高达54Mb/s,而实际数据传输速率只有20Mb/s左右。从成帧效率、信道共享效率和冲突避免效率的角度对IEEE802·11g的MAC层信道利用效率进行了分析,得出这种基于CSMA/CA机制的MAC层信道利用效率... 基于IEEE802·11g的WLAN的标称速率高达54Mb/s,而实际数据传输速率只有20Mb/s左右。从成帧效率、信道共享效率和冲突避免效率的角度对IEEE802·11g的MAC层信道利用效率进行了分析,得出这种基于CSMA/CA机制的MAC层信道利用效率较低。实测结果验证了分析结论的有效性。 展开更多
关键词 IEEE802.11G 媒体接入控制 载渡侦听多路访问/冲突避免 信道利用效率
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S-MAC与IEEE802.15.4的MAC层信道利用效率研究
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作者 周磊 邢建平 +1 位作者 喻其财 周燕 《传感技术学报》 CAS CSCD 北大核心 2007年第7期1564-1567,共4页
提出一种计算MAC层信道利用效率的方法,从成帧效率、信道共享效率和冲突避免三个方面建立模型,对无线传感网络MAC层应用协议S-MAC和IEEE802.15.4进行计算分析,并将此两种协议的信道利用效率与IEEE802.11的信道利用效率进行对比,结合软... 提出一种计算MAC层信道利用效率的方法,从成帧效率、信道共享效率和冲突避免三个方面建立模型,对无线传感网络MAC层应用协议S-MAC和IEEE802.15.4进行计算分析,并将此两种协议的信道利用效率与IEEE802.11的信道利用效率进行对比,结合软件仿真说明S-MAC与IEEE802.15.4两种协议的适用范围. 展开更多
关键词 S-MAC IEEE802.15.4 IEEE802.11 信道利用效率
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提升2G网络信道承载效率的方案及效果
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作者 任刚 安久江 《移动通信》 2013年第12期28-32,共5页
数据用户数、移动网络带宽、智能手机、数据应用四方面的快速发展,导致移动互联网数据流量呈现爆炸式增长。如何挖掘网络信道承载效率来满足流量增长的资源需求,是数据业务优化工作的重中之重。通过分析影响2G网络信道承载效率的因素,... 数据用户数、移动网络带宽、智能手机、数据应用四方面的快速发展,导致移动互联网数据流量呈现爆炸式增长。如何挖掘网络信道承载效率来满足流量增长的资源需求,是数据业务优化工作的重中之重。通过分析影响2G网络信道承载效率的因素,详细介绍了提升2G网络信道承载效率方案,并对应用效果进行了总结。 展开更多
关键词 2G 信道承载效率 业务感知 资源管控
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采煤工作面信道衰落环境下的WSN分簇协议
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作者 钱建生 任鹏 冯小龙 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2017年第3期47-54,共8页
针对无线信号在采煤工作面环境时变衰落特征,提出一种基于跨层设计的分簇协议(LEACH-CL),记录参与竞争节点数和设置滑动窗口,稳定簇首生成数最优.通过探测帧获取节点与基站间的信道效率,联合节点剩余能量信息,作为簇首选则的判断依据,... 针对无线信号在采煤工作面环境时变衰落特征,提出一种基于跨层设计的分簇协议(LEACH-CL),记录参与竞争节点数和设置滑动窗口,稳定簇首生成数最优.通过探测帧获取节点与基站间的信道效率,联合节点剩余能量信息,作为簇首选则的判断依据,设计一种适应无线信号衰落的成簇协议,并通过一定的衰落储备法调节节点不同时期的发送功率.仿真实验表明:与同类3种算法(LEACH、ALEACH和LEACH-SWDN)比较,LEACH-CL协议网络拓扑比较稳定,在信号衰落环境下适应性强,有效地延长了网络的生命期,降低网络丢包率,更适应于采煤工作面复杂多变环境特征. 展开更多
关键词 无线传感器网络 分簇 信道效率 抗衰落 跨层设计
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CDMA/TDD系统的动态信道分配策略 被引量:2
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作者 阚酉浔 高玉良 徐庭新 《无线电工程》 2005年第8期44-46,55,共4页
为了适应上下行业务的不对称性,针对CDMA/TDD系统的动态信道分配(DCA),在慢速动态信道分配方面,提出了根据在线语音用户数和基于上下行数据业务比预测来动态分配上下行时隙数的策略,分析了此策略中上下行业务变化速率和时隙分配速率之... 为了适应上下行业务的不对称性,针对CDMA/TDD系统的动态信道分配(DCA),在慢速动态信道分配方面,提出了根据在线语音用户数和基于上下行数据业务比预测来动态分配上下行时隙数的策略,分析了此策略中上下行业务变化速率和时隙分配速率之间的关系对系统性能的影响。对于快速动态信道分配则设计了一种适用于多业务的呼叫接入控制算法,它对语音业务基于保护信道法而对语音和数据业务之间采取可移动边界法。仿真结果表明:提出的方案可以提供更高的数据处理能力而不影响语音业务的性能,而且信道利用率也得到提高。 展开更多
关键词 CDMA/TDD 动态信道分配(DCA) 信道利用效率 非对称业务
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航空甚高频数据链模式二建模及仿真研究 被引量:4
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作者 贾旭光 张学军 张军 《系统仿真学报》 EI CAS CSCD 北大核心 2007年第21期5046-5050,共5页
依据航空甚高频数据链模式二(VDLM2)协议,基于其物理层和链路层,建立了VDLM2的OPNET模型。在此基础上,仿真分析了平均MAC子层延时和平均链路层延时与飞机数量之间的关系,并与理论值进行了对比,验证了仿真模型的正确性。然后,仿真分析了... 依据航空甚高频数据链模式二(VDLM2)协议,基于其物理层和链路层,建立了VDLM2的OPNET模型。在此基础上,仿真分析了平均MAC子层延时和平均链路层延时与飞机数量之间的关系,并与理论值进行了对比,验证了仿真模型的正确性。然后,仿真分析了吞吐量和信道效率与实供负载之间的关系。分析结果表明,当实供负载位于0.3~0.7区间内时,VDLM2通信系统的传输性能最佳。 展开更多
关键词 甚高频数据链模式二 OPNET 延时 吞吐量 信道效率
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非对称信道传输效率的测量设备无关量子密钥分配研究 被引量:16
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作者 东晨 赵尚弘 +2 位作者 赵卫虎 石磊 赵顾颢 《物理学报》 SCIE EI CAS CSCD 北大核心 2014年第3期28-32,共5页
测量设备无关量子密钥分配方案可以移除所有的探测器侧信道漏洞,通过结合诱骗态方案可以生成无条件安全的密钥.本文研究了非对称信道传输效率下三强度诱骗态测量设备无关量子密钥分配系统的密钥生成率与信道传输损耗的关系,比较了对称... 测量设备无关量子密钥分配方案可以移除所有的探测器侧信道漏洞,通过结合诱骗态方案可以生成无条件安全的密钥.本文研究了非对称信道传输效率下三强度诱骗态测量设备无关量子密钥分配系统的密钥生成率与信道传输损耗的关系,比较了对称信道传输效率和非对称信道传输效率下的距离比率对单边传输效率、单光子误码率和量子密钥生成率的影响,仿真结果表明随着信道不匹配度逐渐增加,可容忍信道传输损耗由对称信道情形下的62 dB分别降至38 dB(距离比率为0.5)和17 dB(距离比率为0.1),能够安全提取密钥的可容忍传输损耗下降较快,密钥生成率的安全传输距离也随之降低.实验中可以采取调节信号光强度的方式提高非对称传输效率下测量设备无关量子密钥分配系统的密钥生成率,为实用的量子密钥分配实验提供了重要的理论参数. 展开更多
关键词 诱骗态 测量设备无关量子密钥分配 非对称信道传输效率
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Highly efficient class-F power amplifier with digital predistortion for WCDMA applications 被引量:1
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作者 季连庆 徐志明 +1 位作者 周健义 翟建锋 《Journal of Southeast University(English Edition)》 EI CAS 2013年第2期125-128,共4页
A digital predistorted class-F power amplifier (PA) using Cree GaN HEMT CGH40010 operating at 2. 12 GHz is presented to obtain high efficiency and excellent linearity for wideband code-division multiple access ( WC... A digital predistorted class-F power amplifier (PA) using Cree GaN HEMT CGH40010 operating at 2. 12 GHz is presented to obtain high efficiency and excellent linearity for wideband code-division multiple access ( WCDMA ) applications. Measurement results with the continuous wave (CW) signals indicate that the designed class-F PA achieves a peak power-added efficiency (PAE) of 75. 2% with an output power of 39.4 dBm. The adjacent channel power ratio (ACPR) of the designed PA after digital predistortion (DPD) decreases from -28. 3 and -27. 5 dBc to -51.9 and -54. 0 dBc, respectively, for a 4-carrier 20 MHz WCDMA signal with 7. 1 dB peak to average power ratio (PAPR). The drain efficiency (DE) of the PA is 37. 8% at an average output power of 33. 3 dBm. The designed power amplifier can be aoolied in the WCDMA system. 展开更多
关键词 digital predistortion peak power-addedefficiency drain efficiency adjacent channel power ratio EFFICIENCY LINEARITY class-F power amplifier
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集群系统设计与各种系统对比
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作者 余德邻 《警察技术》 1995年第1期41-45,共5页
集群系统设计与各种系统对比余德邻这一讲的主要内容是集群系统设计的基本问题,和进入我国的几种有代表性的集群系统的对比。第一节系统主要参数和指标集群系统设计的基本问题是从需求分析出发,在确保系统服务质量和满足符合科学的约... 集群系统设计与各种系统对比余德邻这一讲的主要内容是集群系统设计的基本问题,和进入我国的几种有代表性的集群系统的对比。第一节系统主要参数和指标集群系统设计的基本问题是从需求分析出发,在确保系统服务质量和满足符合科学的约束性条件下,进行信道设计,覆盖网络... 展开更多
关键词 集群系统 信道 信道间隔 信道效率 统设计 频道配置 服务等级 平均延时 话务量 系统对
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Spectral and Energy Efficiency of Downlink MU-MIMO Systems with MRT 被引量:4
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作者 Weiqiang Tan Shi Jin Jide Yuan 《China Communications》 SCIE CSCD 2017年第5期105-111,共7页
This paper studies the achievable spectral efficiency(SE)of downlink multiuser multiple-input-multiple-output(MIMO)system,where the base station(BS)is deployed an arbitrary finite antenna number and communicates simul... This paper studies the achievable spectral efficiency(SE)of downlink multiuser multiple-input-multiple-output(MIMO)system,where the base station(BS)is deployed an arbitrary finite antenna number and communicates simultaneously with many users. We assume that the BS has accurate channel state information(CSI)and adopt maximum ratio transmission(MRT)precoding. An accurate analytical result for the achievable SE is obtained. Based on the analytical result on the achievable SE,we further study the achievable energy efficiency(EE)of multiuser MIMO system by considering an energy consumption model. Results indicate that the increasing number of BS antennas can boost the achievable SE of system,whilst the achievable SE tends to a saturated rate in the high signal-tonoise ratios(SNR)regime. Furthermore,an important conclusion is that the increasing number of users is beneficial for the achievable EE and there is an optimal antenna number to maximize the EE of system. 展开更多
关键词 energy efficiency multiuser MIMO maximum ration transmission spectral efficiency
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高数据业务流量下的无线网络优化 被引量:1
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作者 张会霞 《电信快报(网络与通信)》 2013年第8期31-33,共3页
移动数据业务流量以每年超过50%的速度增长,一方面会占用越来越多的网络资源,给无线网络带来巨大压力,另一方面会导致网络干扰抬升、语音质量下降,影响客户感知。文章从优化信道配置、提升单PDCH(分组数据信道)信道承载效率、开启PS(分... 移动数据业务流量以每年超过50%的速度增长,一方面会占用越来越多的网络资源,给无线网络带来巨大压力,另一方面会导致网络干扰抬升、语音质量下降,影响客户感知。文章从优化信道配置、提升单PDCH(分组数据信道)信道承载效率、开启PS(分组业务)下行功控、加强四网协同、价值小区分析五个不同的角度,给出一些具体优化措施,对于在高数据业务流量下如何进行无线网络优化工作具有一定的参考价值。 展开更多
关键词 单PDCH信道承载效率 四网协同 价值小区 PS下行功控
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Achieving Efficient Channel Utilization for Data Communications in IEEE 802.11 WLAN
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作者 张亮 舒炎泰 《Transactions of Tianjin University》 EI CAS 2005年第6期422-427,共6页
In the IEEE g02. 11 protocol, the adoption of the exponential backoff technique leads to throughput performance strongly dependent on the initial contention window size and, most importantly, on the number of contendi... In the IEEE g02. 11 protocol, the adoption of the exponential backoff technique leads to throughput performance strongly dependent on the initial contention window size and, most importantly, on the number of contending stations considered in the network. This paper proposes a simple but accurate method to dynamically estimate the number of contending stations in a wireless local area network ( WLAN ). Based on estimation, all the mobile stations dynamically adjust the initial contention window in medium access control ( MAC ) layer to avoid collisions. The simulation results show that the proposed algorithm can achieve efficient channel utilization, higher system throughput, and better fairness performance. 展开更多
关键词 IEEE 802.11 wireless local area network( WLAN distributed coordination function DCF
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Dual Adaptive Turbo Coded Modulation for Integrated Multimedia Service Transmission
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作者 左健存 宋文涛 +1 位作者 罗汉文 徐友云 《Journal of Donghua University(English Edition)》 EI CAS 2004年第1期72-77,共6页
This paper proposes a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile multimedia communication, which adapts to both the varying channel characteristics and the QoS of various mult... This paper proposes a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile multimedia communication, which adapts to both the varying channel characteristics and the QoS of various multimedia services simultancously to increase the average system throughput substantially. A pragmatic channeladaptive turbo coded modulation schcme, which comes within 2.5 dB of the Shannon limit, is optimally designed, and then a QoS-adaptive scheme is superimposed to build the dual adaptive architecture. Simulation results show that the novel dual adaption reduces the gap from the fading channel capacity to 2 dB when assuming different services occur in equal probability and the service duration follows exponential distribution. 展开更多
关键词 Dual adaption Turbo coded modulation Fading channels Multimedia services Spectral efficiency
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Double-Space-Cooperation Method for Increasing Channel Capacity
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作者 JIAO Bingli LI Dou 《China Communications》 SCIE CSCD 2015年第12期76-83,共8页
Shannon channel capacity theorem poses highest bit-rate of error free transmission over additive white Gaussian noise channel.In addition,he proved that there exists channel code that can theoretically achieve the cha... Shannon channel capacity theorem poses highest bit-rate of error free transmission over additive white Gaussian noise channel.In addition,he proved that there exists channel code that can theoretically achieve the channel capacity.Indeed fortunately,the latter researchers found some practical channel codes approaching the channel capacity with insignificant losses of spectral efficiency under ignorable bit error rate(BER).The authors note,in general,that bits of the channel codes are not independent of each other in code space.Further,we note that the modulated symbols are not independent among them,as well,in Euclidean Space.By exploiting a usage of the dependencies jointly to signal design,we can transmit two independent signal streams through an additive white Gaussian channel and separate them in Euclidean space at the receiver.The capacity of this approach is found larger than that of Shannon capacity in the same channel assumptions.The numerical results confirm the theoretical procedures. 展开更多
关键词 Euclidean transmit receiver symbol parity latter separate coded additive losses
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GRAPH-THEORETIC ALGORITHM FOR SPECTRUM ALLOCATION IN IEEE 802.22 WIRELESS MESH NETWORK
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作者 He Tao Wang Suoping Zhang Min 《Journal of Electronics(China)》 2010年第4期433-439,共7页
The IEEE 802.22 standard based on wireless Cognitive Radio (CR) is an optimal solution to resolve the inefficient spectrum utility problem. In this paper, we focus on the spectrum allocation in IEEE 802.22 mesh networ... The IEEE 802.22 standard based on wireless Cognitive Radio (CR) is an optimal solution to resolve the inefficient spectrum utility problem. In this paper, we focus on the spectrum allocation in IEEE 802.22 mesh networks and propose a new graph-theory algorithm. The algorithm aims at two objectives: one is the sum of the allocated channel bandwidth is maximum, and the other is the number of users can be active simultaneity is maximum. In this proposed algorithm, the topology of network was modeled as a general graph and could be transformed into a weighted complete bipartite-graph by three processes. The simulations show that the presented algorithm can improve the performance of spectrum allocation. 展开更多
关键词 Cognitive Radio (CR) Wireless Regional Area Network (WRAN) Spectrum allocation
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Energy Efficient Power Allocation Scheme for Distributed Antenna Systems with Target BER Constraint
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作者 Xiangbin Yu Ying Wang +2 位作者 Qiuming Zhu Tao Dong Junya Chu 《China Communications》 SCIE CSCD 2016年第11期234-243,共10页
The energy efficiency(EE) of distributed antenna system with quality of service(Qo S) requirement is investigated over composite Rayleigh fading channel,where the shadow fading,path loss and Rayleigh fading are all co... The energy efficiency(EE) of distributed antenna system with quality of service(Qo S) requirement is investigated over composite Rayleigh fading channel,where the shadow fading,path loss and Rayleigh fading are all considered. Our aim is to maximize the EE which is defined as the ratio of the transmission rate to the total consumed power subject to the maximum transmit power of each remote antenna constraint and Qo S(target BER) requirement. According to the definition of EE and using the upper bound of average EE,the optimized objective function is provided. Based on this,utilizing Karush-KuhnTucker conditions and numerical calculation,a suboptimal energy efficient power allocation(PA) scheme is developed,and the closedform expression of PA coefficients is derived. The scheme may obtain the EE performance close to the existing optimal scheme. Moreover,it has relatively lower complexity than the existing scheme because only the statistic channel information and less iteration are required. Simulation results show the presented scheme is valid and can meet the target BER requirement,and the EE can be increased as target BER requirement decreases. 展开更多
关键词 distributed antenna system energy efficiency power allocation target bit error rate(ber) shadow fading path loss
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A Monolithic InGaP/GaAs HBT PA for TD-SCDMA Handset Application 被引量:1
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作者 毕晓君 张海英 +1 位作者 陈立强 黄清华 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第10期1868-1872,共5页
This paper demonstrates the design and fabrication of a monolithic HBT power amplifier for TD-SCDMA cellu- lar phones that achieves high efficiency and linearity. The two-stage MMIC integrates the input matching circu... This paper demonstrates the design and fabrication of a monolithic HBT power amplifier for TD-SCDMA cellu- lar phones that achieves high efficiency and linearity. The two-stage MMIC integrates the input matching circuits,interstage matching circuits, and active bias circuits in a single chip with size as small as 0.91mm × 0.98mm. The amplifier obtains a power-added efficiency of 43% (15%) and a gain of 28.5dB (24dB) at the high and low operation mode under the 3.4V supply. In addition, the adjacent channel leakage power is below - 45dBc/- 56dBc and - 39dBc/- 50dBc at 1.6MHz/3.2MHz offset in low and high power output modes, respectively, with QPSK modulation. The MMIC offers the potential for low cost production due to small chip size, stable voltage supply, and high performance at the same time. 展开更多
关键词 rD-SCDMA power amplifier InGaP/GaAs HBT PAE ACPR
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