共查询到20条相似文献,搜索用时 140 毫秒
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本文简要介绍了TDMA的特点、基本组成及TDMA网络的监测与管理。重点对TDMA系统中子帧捕获与同步、调制解调、与地面网络的接口等一些TDMA特有的技术进行了分析。文章力求以适用于国内卫星通信的TDMA系统为基础,进行介绍与分析。 相似文献
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分簇结构的无线传感器网络可以更容易的进行数据融合,可以减少网络能量消耗,增加网络的健壮性,因此分簇算法被广泛的用在无线传感器网络中。但现存的算法不能满足网络拓扑变化较大、较频繁的网络。针对移动性较大的无线传感器网络,提出了DEAMC,一种分布的、节能的、自适应的、动态的分簇协议。根据DEAMC,剩余能量越多,成为簇头的可能性越大,且簇头均匀分布。DEAMC用是一种TDMA协议,利用TDMA可以减少能量消耗,延长网络的寿命。DEAMC是一种FDMA协议,利用FDMA可以避免信号碰撞。 相似文献
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This paper concentrates on the control of individual burst transmissions of traffic and reference stations in TDMA and SS/ TDMA networks. In a TDMA system, the principal task of a TDMA terminal is to transmit each burst at the proper time to assure that, at the satellite, the burst resides in its assigned location in the TDMA frame. The composite of assigned positions for all bursts in the TDMA frame, or frames if more than one transponder is involved, is called the burst time plan. The paper discusses a specific concept of control used by a station to acquire and synchronize its burst transmission to assigned time slot(s) in the TDMA frame. The concept is applied to single-beam (global or regional) and muitibeam systems. The method used controls the instant of traffic burst transmission by introducing a time delay at each station which causes the round-trip propagation time between the satellite and all earth stations to be equal for burst position control purposes. This time delay is simple to implement in the TDMA terminal's timing circuitry and does not require the storage of traffic to accomplish it. It is also shown that the control method leads to a simple means for accomplishing synchronous burst time plan changes throughout the network. The functions of the reference stations needed to accomplish the burst time plan control are defined and explained. The discussion extends to SS/TDMA, and explains how the satellite switch state time plan change can be synchronized to the overall network burst time plan change. 相似文献
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分析了高速运动对TDMA卫星通信系统造成的影响,提出一种适用于高速运动环境的TDMA卫星通信同步控制技术。利用装载平台的导航信息辅助实现多普勒频偏的快速捕获,结合TDMA卫星通信特点完成多普勒频偏的跟踪补偿,同时使用多普勒频偏估计并修正运动引起的定时误差,可以在不改变TDMA卫星通信网现有其他设备技术状态的情况下,消除高速运动产生的影响,实现高速运动环境下TDMA卫星通信终端的快速入网和同步保持。 相似文献
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A method for frame synchronization in a photonic network of time multiplexed space switches is presented. The method, which is based on a feedback scheme, is first introduced for frame synchronization in a single-switch configuration. The feedback scheme is then extended to both hierarchical (tree topology) and nonhierarchical (general topology) multiswitch configurations. Using this feedback scheme has the advantage of providing a mechanism for frame synchronization to be achieved initially, without the need for accurate transmission time measurements, and allowing synchronization to be maintained within very tight bounds. The methods presented require additional electronics at the switches, but electronics only for control purposes, not in the path of the information bits. However, optical delay elements are needed in the path of information bits on some links of the network. The proposed schemes also reduce the amount of synchronization equipment needed, compared to other methods 相似文献
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TDMA网络的FH-OFDM同步算法研究 总被引:1,自引:1,他引:0
首先对比了FH-OFDM(跳频OFDM)两种组成形式的优缺点,据此选择了其中一种形式构建了TDMA网络的FH-OFDM的系统模型;然后分别讨论了该系统中跳频同步、时分多址(TDMA)网同步和正交频分复用(OFDM)同步的算法以及三者之间的关系;并对OFDM同步算法进行了深入讨论,构造了基于数据辅助估计的FH-OFDM跳帧结构;利用短训练符号进行了OFDM同步的Matlab仿真,分析了影响频偏估计的因素,并提出了一种工程上选择训练符号的参考方法。 相似文献
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跳频组网的核心技术之一是跳频同步问题。对现有的跳频同步方案做了一些改进,分析了时间信息TOD与同步头频率使用原理、同步头频率捕获过程、跳频同步与跟踪过程。时分多址接入(TDMA)的前提条件需要跳频同步的完成,结合时隙同步方法和跳频同步技术阐述了基于TDMA的AdHoc网络跳频组网的实现过程。 相似文献
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Many transmission scheduling algorithms have been proposed to maximize spatial reuse and minimize the time division multiple access (TDMA) frame length in multihop packet radio networks. Almost all existing algorithms assume exact network topology information and require recomputations when the network topology changes. In addition, existing work focuses on single channel TDMA systems. In this paper, we propose a multichannel topology-transparent algorithm based on latin squares. The proposed algorithm has the flexibility to allow the growth of the network, i.e., the network can add more mobile nodes without recomputation of transmission schedules for existing nodes. At the same time, a minimum throughput is guaranteed. We analyze the efficiency of this algorithm and examine the topology-transparent characteristics and the sensitivity on design parameters by analytical and simulation techniques 相似文献
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In this paper, we design high-speed optical fiber networks based on the time-division multiple-access (TDMA) technique. To achieve an ultrahigh throughput, optical signal processing should be used in the network. We present a feasible scheme to implement optical TDMA networks, with the emphasis on optical clock distribution, synchronization, and optical time demultiplexing. Since the proposed network uses two wavelengths to carry optical TDMA and clock signals respectively, at each TDMA receiver slot synchronization is feasibly achieved by using simple optical delay lines to process the separated optical clock and TDMA signals. This in turn allows us to build a large-scale distribution network which is attractive for future HDTV broadcasting applications. Using the proposed scheme also allows to implement a high-capacity broadcast and select optical TDMA network for real-time data communications. 相似文献
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同步技术是TDMA系统的主要关键技术之一,帧同步中的漏同步、假同步概率以及同步建立时间是影响同步性能的主要原因。文章介绍了三种帧同步技术,并对这些技术的性能进行了分析比较,最后给出了进一步的研究方向。 相似文献
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