针对采用分布式并行方法仿真WLAN(wireless local area network)场景时存在的随终端节点个数增加而效率降低的问题,提出了一种面向WLAN的分布式分层并行仿真方法。基于WLAN的星状网络拓扑结构,令仿真接入节点的进程为主进程,负责WLAN全...针对采用分布式并行方法仿真WLAN(wireless local area network)场景时存在的随终端节点个数增加而效率降低的问题,提出了一种面向WLAN的分布式分层并行仿真方法。基于WLAN的星状网络拓扑结构,令仿真接入节点的进程为主进程,负责WLAN全网中其他仿真节点的时间同步;将所有仿真终端节点的进程均匀分为若干组,由组长负责该组内进程的同步。在主进程广播仿真开始事件后,组长进程先收集本组组员终端节点推进结束消息,当收齐后再向主进程汇报。形成“主进程-组长进程-组员进程”的3层分层结构。在不同计算负荷下,仿真分析并得到了分层仿真方法的时间增益因子闭合表达式。仿真结果表明,与现有不分层的仿真方法相比,当平均计算负荷为1.2倍单位时长、节点个数为100时,所提分层仿真方法的增益可达50%。展开更多
In this paper,we propose a Multi-token Sector Antenna Neighbor Discovery(M-SAND)protocol to enhance the efficiency of neighbor discovery in asynchronous directional ad hoc networks.The central concept of our work invo...In this paper,we propose a Multi-token Sector Antenna Neighbor Discovery(M-SAND)protocol to enhance the efficiency of neighbor discovery in asynchronous directional ad hoc networks.The central concept of our work involves maintaining multiple tokens across the network.To prevent mutual interference among multi-token holders,we introduce the time and space non-interference theorems.Furthermore,we propose a master-slave strategy between tokens.When the master token holder(MTH)performs the neighbor discovery,it decides which 1-hop neighbor is the next MTH and which 2-hop neighbors can be the new slave token holders(STHs).Using this approach,the MTH and multiple STHs can simultaneously discover their neighbors without causing interference with each other.Building on this foundation,we provide a comprehensive procedure for the M-SAND protocol.We also conduct theoretical analyses on the maximum number of STHs and the lower bound of multi-token generation probability.Finally,simulation results demonstrate the time efficiency of the M-SAND protocol.When compared to the QSAND protocol,which uses only one token,the total neighbor discovery time is reduced by 28% when 6beams and 112 nodes are employed.展开更多
为了提升下一代无线局域网(wireless local area network,WLAN)高密集场景下的区域吞吐量,正交频分多址接入(orthogonal frequency division multiple access,OFDMA)作为关键技术之一已被下一代WLAN通信标准采纳。然而,现有研究所提出的...为了提升下一代无线局域网(wireless local area network,WLAN)高密集场景下的区域吞吐量,正交频分多址接入(orthogonal frequency division multiple access,OFDMA)作为关键技术之一已被下一代WLAN通信标准采纳。然而,现有研究所提出的OFDMA多址接入技术均存在传输干扰扩散问题,即多个并行接入的节点位于位置分散的区域,从而对周边的传输干扰面积加大。提出一种空间聚集群组的OFDMA多址接入协议,空间位置接近的节点构成空间聚集群组,该协议使得空间聚集群组内的节点采用OFDMA的方式并行接入和传输,从而降低多个节点同时传输时的干扰范围,进而提升区域吞吐量。此外,根据网络仿真软件得出的结果,进行理论推导,理论分析与仿真结果相吻合。仿真结果表明,当小区节点数为100时,所提出协议的区域吞吐量比已有OFDMA协议和分布式协调功能协议分别提升15.98%和31.26%。为设计下一代WLAN媒体接入控制协议提供参考。展开更多
在定向航空中继网络中,中继飞机利用定向天线通信距离远、发射功率小、无线信号干扰范围小等优点,辅助地面节点克服地形遮挡、信号衰弱大、通信距离受限等缺点,以较少的跳数进行通信,有效降低端到端数据传输时延、提高网络吞吐量。针对...在定向航空中继网络中,中继飞机利用定向天线通信距离远、发射功率小、无线信号干扰范围小等优点,辅助地面节点克服地形遮挡、信号衰弱大、通信距离受限等缺点,以较少的跳数进行通信,有效降低端到端数据传输时延、提高网络吞吐量。针对定向航空中继网络中由于通信链路长、无线信号传播时延与数据传输时延相近,所引起的通信时延扩展、多址接入协议效率低等问题,提出了一种基于通信链路距离进行分环的时分多址接入协议(link distance division based time division multiple access protocol,LDD-TDMA)。与传统的TDMA多址接入协议中所有链路均使用相同的时隙长度不同,LDD-TDMA根据通信链路的距离远近使用不同的时隙长度。进一步为了简化协议实现,提出通信覆盖范围分环的概念,使得处于同一个环内链路距离相近的节点使用相同的时隙长度。接着,建模分析并推导出了最大化多址接入效率的分环的个数、分环半径与节点最大通信距离之间的闭合表达式。最后,仿真结果表明,当中继飞机最大通信距离为200 km、分环个数为4时,LDD-TDMA的多址接入效率相较于传统的TDMA可提高13.37%。展开更多
The problem of robustness-supported user association and small cell station(SCS) switching ON/OFF strategies in 5G millimeter wave(mm-wave) networks is investigated, where the robustness of access links is ensured and...The problem of robustness-supported user association and small cell station(SCS) switching ON/OFF strategies in 5G millimeter wave(mm-wave) networks is investigated, where the robustness of access links is ensured and the number of active SCSs is minimized for the reduction of the aggregation power consumption. Firstly, the problem is formulated as an integer programming(IP) problem. Then the problem is proved as a NP-hard problem by means of the simplification into the minimum dominant set(MDS), which is a NP-hard problem and is intractable to be solved in polynomial time. Secondly, a greedy-idea-based heuristic algorithm(GIHA) is proposed under the consideration of the complexity of the original optimization problem. Finally, superiorities of GIHA are demonstrated with the extensive simulations in 60 GHz mm-wave ultra-dense network in terms of access robustness and aggregate power consumption.展开更多
针对下一代无线局域网(wireless local access network,WLAN)多小区高密集部署重叠覆盖场景中,冲突加剧所导致的缓存信息收集效率低、系统吞吐量急剧下降的问题,提出一种基于接入点协作的多小区多用户全双工多址接入协议(access point c...针对下一代无线局域网(wireless local access network,WLAN)多小区高密集部署重叠覆盖场景中,冲突加剧所导致的缓存信息收集效率低、系统吞吐量急剧下降的问题,提出一种基于接入点协作的多小区多用户全双工多址接入协议(access point cooperation based multi basic service set multi-user full duplex multiple access protocol,CMMFD)。设计了一种面向重叠覆盖区域站点(station,STA)的信道资源分配算法,该算法中接入控制(access control,AC)设备根据重叠覆盖区域中STA个数的占比,为所有STA分配回复缓存和干扰信息(buffer state and interference information,BI)时所使用的信道资源;设计了一种基于接入点(access point,AP)协同发送触发帧收集所有STA BI信息的协议流程,STA在收到触发帧之后,根据AC分配的信道资源以概率P接入信道回复并汇报BI信息;设计了一种基于全双工的多小区多用户信道资源分配算法,AC根据所有AP上报的BI信息,分配信道资源并调度多小区中STA在子信道上进行多用户全双工传输。仿真结果表明:在多小区重叠覆盖场景下,相比Mu-FuPlex协议,EnFD-OMAX协议,CMMFD协议的系统吞吐量提升了29.6%。展开更多
Both high-dense wireless connectivity and ultra-huge network capacity are main challenges of next generation broadband networks.As one of its key promising technologies,non-orthogonal multi-ple access(NOMA)scheme can ...Both high-dense wireless connectivity and ultra-huge network capacity are main challenges of next generation broadband networks.As one of its key promising technologies,non-orthogonal multi-ple access(NOMA)scheme can solve those challenges and meet those needs to some extent,in the way that different user equipments(UEs)multiplex on the same resource.Researchers around the world have presented numerous NOMA solutions.Among those,sparse code multiple access(SC-MA)technology is a typical NOMA solution.It supports scheduled access and random access which can be called granted access and grant-free access respectively.But resources allocated to granted UEs and grant-free UEs are strictly separated.In order to improve resource utilization,a hybrid non-orthogonal multiple access scheme is proposed.It allows granted UEs and grant-free UEs sharing the same resource unit in terms of fine-grained integration.On the basis,a resource allocation method is further brought forward based on genetic algorithm.It optimizes resource allocation of all UEs by mapping resource distribution issue to an optimization problem.Comparing throughputs of four meth-ods,simulation results demonstrate the proposed genetic algorithm has better throughput gain.展开更多
文摘针对采用分布式并行方法仿真WLAN(wireless local area network)场景时存在的随终端节点个数增加而效率降低的问题,提出了一种面向WLAN的分布式分层并行仿真方法。基于WLAN的星状网络拓扑结构,令仿真接入节点的进程为主进程,负责WLAN全网中其他仿真节点的时间同步;将所有仿真终端节点的进程均匀分为若干组,由组长负责该组内进程的同步。在主进程广播仿真开始事件后,组长进程先收集本组组员终端节点推进结束消息,当收齐后再向主进程汇报。形成“主进程-组长进程-组员进程”的3层分层结构。在不同计算负荷下,仿真分析并得到了分层仿真方法的时间增益因子闭合表达式。仿真结果表明,与现有不分层的仿真方法相比,当平均计算负荷为1.2倍单位时长、节点个数为100时,所提分层仿真方法的增益可达50%。
基金supported in part by the National Natural Science Foundations of CHINA(Grant No.61771392,No.61771390,No.61871322 and No.61501373)Science and Technology on Avionics Integration Laboratory and the Aeronautical Science Foundation of China(Grant No.201955053002 and No.20185553035)。
文摘In this paper,we propose a Multi-token Sector Antenna Neighbor Discovery(M-SAND)protocol to enhance the efficiency of neighbor discovery in asynchronous directional ad hoc networks.The central concept of our work involves maintaining multiple tokens across the network.To prevent mutual interference among multi-token holders,we introduce the time and space non-interference theorems.Furthermore,we propose a master-slave strategy between tokens.When the master token holder(MTH)performs the neighbor discovery,it decides which 1-hop neighbor is the next MTH and which 2-hop neighbors can be the new slave token holders(STHs).Using this approach,the MTH and multiple STHs can simultaneously discover their neighbors without causing interference with each other.Building on this foundation,we provide a comprehensive procedure for the M-SAND protocol.We also conduct theoretical analyses on the maximum number of STHs and the lower bound of multi-token generation probability.Finally,simulation results demonstrate the time efficiency of the M-SAND protocol.When compared to the QSAND protocol,which uses only one token,the total neighbor discovery time is reduced by 28% when 6beams and 112 nodes are employed.
文摘为了提升下一代无线局域网(wireless local area network,WLAN)高密集场景下的区域吞吐量,正交频分多址接入(orthogonal frequency division multiple access,OFDMA)作为关键技术之一已被下一代WLAN通信标准采纳。然而,现有研究所提出的OFDMA多址接入技术均存在传输干扰扩散问题,即多个并行接入的节点位于位置分散的区域,从而对周边的传输干扰面积加大。提出一种空间聚集群组的OFDMA多址接入协议,空间位置接近的节点构成空间聚集群组,该协议使得空间聚集群组内的节点采用OFDMA的方式并行接入和传输,从而降低多个节点同时传输时的干扰范围,进而提升区域吞吐量。此外,根据网络仿真软件得出的结果,进行理论推导,理论分析与仿真结果相吻合。仿真结果表明,当小区节点数为100时,所提出协议的区域吞吐量比已有OFDMA协议和分布式协调功能协议分别提升15.98%和31.26%。为设计下一代WLAN媒体接入控制协议提供参考。
文摘在定向航空中继网络中,中继飞机利用定向天线通信距离远、发射功率小、无线信号干扰范围小等优点,辅助地面节点克服地形遮挡、信号衰弱大、通信距离受限等缺点,以较少的跳数进行通信,有效降低端到端数据传输时延、提高网络吞吐量。针对定向航空中继网络中由于通信链路长、无线信号传播时延与数据传输时延相近,所引起的通信时延扩展、多址接入协议效率低等问题,提出了一种基于通信链路距离进行分环的时分多址接入协议(link distance division based time division multiple access protocol,LDD-TDMA)。与传统的TDMA多址接入协议中所有链路均使用相同的时隙长度不同,LDD-TDMA根据通信链路的距离远近使用不同的时隙长度。进一步为了简化协议实现,提出通信覆盖范围分环的概念,使得处于同一个环内链路距离相近的节点使用相同的时隙长度。接着,建模分析并推导出了最大化多址接入效率的分环的个数、分环半径与节点最大通信距离之间的闭合表达式。最后,仿真结果表明,当中继飞机最大通信距离为200 km、分环个数为4时,LDD-TDMA的多址接入效率相较于传统的TDMA可提高13.37%。
基金Supported by the National Natural Science Foundations of China(No.61771392,61771390,61871322,61501373,61271279)the National High Tochnology Research and Development Program of China(No.2014AA01A707,2015AA01A704)the Science and Technology on Avionics Integration Laboratory(No.20185553035)。
文摘The problem of robustness-supported user association and small cell station(SCS) switching ON/OFF strategies in 5G millimeter wave(mm-wave) networks is investigated, where the robustness of access links is ensured and the number of active SCSs is minimized for the reduction of the aggregation power consumption. Firstly, the problem is formulated as an integer programming(IP) problem. Then the problem is proved as a NP-hard problem by means of the simplification into the minimum dominant set(MDS), which is a NP-hard problem and is intractable to be solved in polynomial time. Secondly, a greedy-idea-based heuristic algorithm(GIHA) is proposed under the consideration of the complexity of the original optimization problem. Finally, superiorities of GIHA are demonstrated with the extensive simulations in 60 GHz mm-wave ultra-dense network in terms of access robustness and aggregate power consumption.
文摘针对下一代无线局域网(wireless local access network,WLAN)多小区高密集部署重叠覆盖场景中,冲突加剧所导致的缓存信息收集效率低、系统吞吐量急剧下降的问题,提出一种基于接入点协作的多小区多用户全双工多址接入协议(access point cooperation based multi basic service set multi-user full duplex multiple access protocol,CMMFD)。设计了一种面向重叠覆盖区域站点(station,STA)的信道资源分配算法,该算法中接入控制(access control,AC)设备根据重叠覆盖区域中STA个数的占比,为所有STA分配回复缓存和干扰信息(buffer state and interference information,BI)时所使用的信道资源;设计了一种基于接入点(access point,AP)协同发送触发帧收集所有STA BI信息的协议流程,STA在收到触发帧之后,根据AC分配的信道资源以概率P接入信道回复并汇报BI信息;设计了一种基于全双工的多小区多用户信道资源分配算法,AC根据所有AP上报的BI信息,分配信道资源并调度多小区中STA在子信道上进行多用户全双工传输。仿真结果表明:在多小区重叠覆盖场景下,相比Mu-FuPlex协议,EnFD-OMAX协议,CMMFD协议的系统吞吐量提升了29.6%。
基金Supported by the National Natural Science Foundation of China(No.61871322,61771392,61771390,61501373,61271279)the National Science and Technology Major Special Project(2016ZX03001018-004).
文摘Both high-dense wireless connectivity and ultra-huge network capacity are main challenges of next generation broadband networks.As one of its key promising technologies,non-orthogonal multi-ple access(NOMA)scheme can solve those challenges and meet those needs to some extent,in the way that different user equipments(UEs)multiplex on the same resource.Researchers around the world have presented numerous NOMA solutions.Among those,sparse code multiple access(SC-MA)technology is a typical NOMA solution.It supports scheduled access and random access which can be called granted access and grant-free access respectively.But resources allocated to granted UEs and grant-free UEs are strictly separated.In order to improve resource utilization,a hybrid non-orthogonal multiple access scheme is proposed.It allows granted UEs and grant-free UEs sharing the same resource unit in terms of fine-grained integration.On the basis,a resource allocation method is further brought forward based on genetic algorithm.It optimizes resource allocation of all UEs by mapping resource distribution issue to an optimization problem.Comparing throughputs of four meth-ods,simulation results demonstrate the proposed genetic algorithm has better throughput gain.
