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研究了HINOC MAC协议测试实现方案和关键接口设计.首先提出了基于TTCN-3的HINOC MAC协议一致性测试平台架构,它包含测试例开发和协议适配器接口开发两部分.重点设计开发TRI(TTCN-3 Runtime Interface)和TCI(TTCN-3Control Interface)接口,以实现信息帧的发送与接收、定时器操作以及编码与解码功能.最后通过搭建实际的测试平台对接口的有效性进行验证,实验结果表明该设计方案可以实现HINOC协议MAC层信令的测试. 相似文献
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HINOC(High performance Network Over Coax)是一种新的具有自主知识产权的利用同轴电缆带外信道传输宽带综合数据业务的接入技术,本文提出一种HIMAC(HINOC MAC)硬件协处理器设计方案,重点介绍了调度器的设计与实现,通过搭建HINOC节点FPGA演示验证系统,实际测试表明该调度方案设计正确,达到预期目标. 相似文献
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HINOC是一种利用有线电视网已有的同轴电缆线路和分配网络,组建而成的最后100米范围内的宽带接入网。HIMAC协处理器是HINOC网络设备中关键网络交换芯片,本文简要的介绍了HIMAC协处理器地址转发表数据转发原理,并给出了其具体的设计及实现方法。 相似文献
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为了满足B3G系统高速数据传输的要求,需要设计高速MAC与物理层适配.介绍了B3G试验系统及MAC层的概念,阐述了高速MAC设计的原理和流程,给出了实现结果的性能分析.该MAC设计基于FPGA实现,与传统的CPU软件实现MAC设计相比,实时性、灵活性更强,执行速度更快.用硬件资源换取处理速度的方法为下一代移动通信的系统设计提供了新的设计思路. 相似文献
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The main goal of the IEEE 802.11n standard is to achieve more than 100 Mbps of throughput at the MAC service access point. This high throughput has been achieved via many enhancements in both the physical and MAC layers. One of the MAC enhancements is the frame aggregation in which multiple frames are concatenated into a single large frame before being transmitted. The 802.11n MAC layer defines two types of aggregation, aggregate MAC service data unit (A-MSDU) and aggregate MAC protocol data unit (A-MPDU). The A-MPDU outperforms A-MSDU due to its large aggregation size and the subframes retransmission in erroneous channels. However, in error free channels and under the same aggregation size the A-MSDU performs better than the A-MPDU due to its smaller headers. Thus, adding a selective retransmission capability to the A-MSDU would improve the system performance. In this paper, we have proposed an MSDU frame aggregation scheme that enables selective retransmission at the MSDU level without altering the original MAC header. In this proposed scheme an implicit sequence control mechanism has been introduced in order to keep the frames in sequence and preserve their correct order at the receiver side. The results show that the proposed scheme improves the system performance in terms of throughput and delay even under highly erroneous channels. 相似文献
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提出了一种基于JTAG协议的嵌入式CISC处理器的调试系统的设计方案。针对自主研发的教学用JU-C2型处理器设计了片上调试器和CPU内部寄存器扫描链,为构成一个完整的调试系统,还设计了USB-JTAG协议转换器和PC机控制软件。调试系统可以实现微指令级和机器指令级的单步、断点以及CPU内部寄存器值的查看和PC(程序计数器)写入,还有CPU的运行停止和复位这些常用的调试功能。分别介绍了系统的各个组成部分以及它们的原理,进行了系统测试,验证系统工作的正确性。调试系统对CPU内部数据通路侵入性较小,在教学中也有一定的实用性。 相似文献
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《Computer Communications》2001,24(3-4):344-352
This paper presents a new media access control (MAC) protocol based on forward error control (FEC), which is appropriate for supporting real-time traffic with strict QoS requirements in wireless ATM networks. As the channel BER in wireless environments is very high and varying 10−5–10−2, previous schemes that use powerful FEC have combated to overcome this noisy channel condition at the cost of valuable bandwidth. As most previous works have been dedicated to maximize the channel efficiency, they were not able to meet QoS requirements of real-time applications in wireless networks. A new MAC protocol proposed in this paper is designed to guarantee the throughput requested by a real-time traffic user while keeping the bandwidth consumption at a minimum. The proposed scheme is for a TDMA system and uses adaptive FEC. We analyze the wireless channel and model it as a two-state error control system to design an efficient MAC protocol. We use simulation experiments to show how the proposed scheme provides QoS guarantees, and compare it with the CDMA system in terms of capacity, i.e. the number of users that can be supported. 相似文献
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周期性休眠的PCF机制虽然较好地解决了无线传感器网络的能耗问题,但没有考虑节点的负载状态,降低了系统性能,也增加了系统的查询能耗.以限定(K=1)服务为基础,提出了一种改进的PCF轮询控制协议,即具有混合服务策略的无线传感器网络轮询接入控制协议PCF-SS.该协议在保障公平性的前提下,能够根据节点状态动态调整优先级并改变服务K值,中心服务器AP则根据各节点的服务K值在每轮服务时对节点的下一轮服务时间进行预估计,并采用统一的服务时间表唤醒节点,达到节能的效果.仿真实验表明系统的平均等待时间、平均排队队长等性能指标比周期性休眠的PCF机制要好,能量的有效利用率更高,具有更长的生命周期,适合作为无线传感器网络的MAC控制协议. 相似文献