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介绍无线局域网IEEE802.11标准中物理层采用的调制技术——CCK(补码键控),详细介绍了CCK的基本原理和系统框图,并分析它们的性能。 相似文献
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文章全面介绍了用于IEEE-802.11b无线局域网的CCK方式.我们首先讨论了CCK码字的由来和特征,接下来重点介绍了在基带处理中CCK方式的调制和解调电路的设计,最后提了一下上述设计在实现中的考虑. 相似文献
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阐述了直接序列扩频技术对IEEE802.11无线局域网协议的解决方案,介绍了支持802.11协议的全数 字化直接序列扩频处理芯片,分析了目前无线网络中采用的MBOK、CCK多进制正交码扩频调制方式及性能。 相似文献
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《广播与电视技术》2001,28(11)
据报道 ,卓越的宽带网络产品提供商——— ZONET公司近日推出型号为 ZEW 2 0 0 0的无线局域网卡。在国内 ,无线局域网的技术和产品由于其不可替代的优点 ,将会迅速地应用于需要在移动中连网和在网间漫游的场合 ,并在不易布线的地方和远距离的数据处理节点提供强大的网络支持。ZEW 2 0 0 0该产品为 11Mbps无线局域网卡 ,具备即插即用的 USB接口 ,采用IEEE80 2 .11b / IEEE80 2 .3 / IEEE80 2 .1d标准 ,CCK/ DQPSK/ DBPSK调制方式以及 WEP algorith m加密 ,驱动支持 Win dows98/ ME/ 2 0 0 0 ,NT4 .0 ,功耗在传输时为 3 3… 相似文献
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补码键控技术是一种多进制编码扩频技术。本文介绍了该技术的相关函数特征及序列结构,并以无线局域网基带处理器HFA3861A为例,介绍了CCK扩频调制方式的典型应用。 相似文献
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1997年,IEEE发布了802.11协议,它成为无线局域网领域内第一个被国际公认的协议.在1999年9月,IEEE又提出了802.11b"High Rate"协议,用来对802.11协议进行补充.802.11b在原802.11的1Mbps和2Mbps速率下又增加了5.5Mbps和11Mbps两个新的网络传输速率. 相似文献
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李家泳杜宽澄 《无线电技术与信息》2005,(9):68-70
高速下行分组接入(High Speed Downlink Package Access,HSDPA),理论上能提供高达14.4Mbps的用户数据率。HSDPA通过改进无线调制方式和无线接入管理方法来实现,属于3GPP R5 WCDMA系统规范,在未来R6版本中将包含多天线技术,最大速率提高到30Mbps。 相似文献
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Tzi-Dar Chiueh Shu-Mei Li 《Communications Letters, IEEE》2001,5(5):191-193
In high-rate wireless LAN, complementary code keying (CCK) is adopted in the IEEE 802.11b standard to support data rates up to 11 Mbps, much higher than the 2-Mbps data rate in the previous wireless LAN standard. Due to less-than-ideal characteristics of the CCK codewords, the CCK performs quite poorly in large-delay-spread multipath channels. In this paper, a new modulation scheme that combines the trellis coding with the CCK modulation is proposed. This scheme is shown, through simulation, to achieve much better error rate performance in medium-to-large channel delay spread environments 相似文献
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本文提出两种将IEEE802.11bWLAN物理层数据速率提高到16.5Mbps的编码和译码方法。这两个方案都继续采用原IEEE802.11b中对于5.5和11Mbps速率所采用的CCK编码方法。两个方案的编码过程变化不大,第一方案的译码还是采用对5.5和11Mbps数据率所使用的快速WALSH变换(FWT),第二个方案的译码被修改成适合16.5Mbps数据率的快速WALSH变换(FWT)。最后通过仿真比较了这两个方案在无多径干扰的AWGN信道上的性能,结果表明第二个方案优于第一个。 相似文献
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Ghovanloo M. Najafi K. 《IEEE transactions on circuits and systems. I, Regular papers》2004,51(12):2374-2383
A high data-rate frequency-shift keying (FSK) modulation protocol, a wideband inductive link, and three demodulator circuits have been developed with a data-rate-to-carrier-frequency ratio of up to 67%. The primary application of this novel FSK modulation/demodulation technique is to send data to inductively powered wireless biomedical implants at data rates in excess of 1 Mbps, using comparable carrier frequencies. This method can also be used in other applications such as radio-frequency identification tags and contactless smartcards by adding a back telemetry link. The inductive link utilizes a series-parallel inductive-capacitance tank combination on the transmitter side to provide more than 5 MHz of bandwidth. The demodulator circuits detect data bits by directly measuring the duration of each received FSK carrier cycle, as well as derive a constant frequency clock, which is used to sample the data bits. One of the demodulator circuits, digital FSK, occupies 0.29 mm/sup 2/ in the AMI 1.5-/spl mu/m, 2M/2P, standard CMOS process, and consumes 0.38 mW at 5 V. This circuit is simulated up to 4 Mbps, and experimentally tested up to 2.5 Mbps with a bit error rate of 10/sup -5/, while receiving a 5/10-MHz FSK carrier signal. It is also used in a wireless implantable neural microstimulation system. 相似文献
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随着多个领域对无线通信的速率要求越来越高,从几百Mbps到几十Gbps,高速无线通信成为通信技术的一个前沿研究热点,并取得了重要的研究进展。详细介绍了微波毫米波通信系统、光通信系统和太赫兹通信系统3类主要的高速无线通信系统各自的研究现状及取得的成果,分析了它们采用的技术路线,并比较了各系统的优缺点,其中重点关注了它们各自采用的调制解调方式,最后展望了高速无线通信技术进一步的研究方向。 相似文献
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Richard Van Nee V. K. Jones Geert Awater Allert Van Zelst James Gardner Greg Steele 《Wireless Personal Communications》2006,37(3-4):445-453
An overview is given of the new IEEE 802.11n standard. This is the first wireless LAN standard based on MIMO-OFDM, a technique pioneered by Airgo Networks to give a significant performance increase in both range and rate relative to conventional wireless LAN. Performance results show that net user throughputs over 100 Mbps are achievable, which is about four times larger than the maximum achievable throughput using IEEE 802.11a/g. For the same throughput, MIMO-OFDM achieves a range that is about 3 times larger than non-MIMO systems. This significant improvement in range-rate performance makes MIMO-OFDM the ideal solution not only for wireless LAN, but also for home entertainment networks and 4G networks.
Richard van Nee received the M.Sc. degree in Electrical Engineering from Twente University in Enschede, the Netherlands, in 1990. In May 1995, he received the PhD degree from Delft University of Technology. From 1995 to 2000, he worked for Lucent Technologies Bell Labs on wireless LAN transmission techniques. He was one of the original proposers of the CCK and OFDM modulation techniques which were adopted by the IEEE 802.11b and IEEE802.11a wireless LAN standards. In 2001, he cofounded Airgo Networks that developed the first MIMO-OFDM modem for wireless LAN and which techniques form the basis of the IEEE 802.11n standard. Together with Ramjee Prasad, he wrote a book on OFDM, entitled ‘OFDM for Mobile Multimedia Communications.’ In 2002 he received the Dutch Veder award for his contributions to standardization of wireless communications. 相似文献
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随着无线通信速率需求的增加和材料生长、器件工艺制作水平的提高,太赫兹(THz)通信已成为未来高速无线通信系统发展的一个重要方向。介绍了太赫兹通信的特点以及国际上太赫兹通信系统的发展现状,并报导了一种利用太赫兹量子级联激光器(THz QCL)作为发射源,太赫兹量子阱探测器(THz QWP)作为接收器的太赫兹数字通信演示系统。该系统采用On-Off-Key(OOK)调制和直接强度检测方式,通信频点为3.9 THz,通信距离为2.2 m,传输速率可达1 Mbps 以上。最后探讨了该系统的带宽限制因素及其在通信速率方面的潜力。 相似文献
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KaziTakpaya 《电子科学学刊(英文版)》2003,20(6):446-450
A wireless floppy disk drive is proposed for home and office wireless local area network. The proposed floppy drive uses turbo coding-decoding in the transceiver PHYsical layer (PHY) to improve system performance. The data transmission rate is about 11 Mbps. The covered distance is 30 meters in obstructed environment and 100 m in free space. 相似文献