中英对照 超宽带技术与其它短距离无线通信技术的比较

1、超宽带技术与其它短距离无线通信技术的比较随着个人通信消费电子产业的迅猛发展，短距离无线通信领域的各种新技术、新方法层出不穷，朝着更快、更方便、更安全有效等方面进行发展。新的技术在 Intel 接入、信息家电、移动办公、工业化等各个领域得到了广泛的运用。其中，超宽带（Ultra Wide Band，UWB）技术是在 20世纪90 年代以后发展起来的一种具有巨大发展潜力的新型无线通信技术，被列为未来通信的十大技术之一 。1 超宽带无线通信 1.1 超宽带技术简介 UWB（Ultra Wideband，超宽带）技术是目前正被广泛研究的一种新兴无线通信技术，现在已经成为高速无线个人网 （WPAN）的首

2、选技术。UWB是指信号带宽大于 500MHz或者是信号带宽与中心频率之比大于25% 的通信技术。与常见的通信方式使用连续的载波不同，UWB 中使用的无线信号中心频率为 4.1GHz，带宽为 1.4GHz，频谱范围很宽，但是发射功率非常低。通信速度在250Kbit10Mbit/秒之间。在 250Kbit/秒的传输速度下可确保 30m的通信距离。在短距离（13m 以下）有很大优势，最高传输速度可达 1Gb/S。而传统的窄带技术在长距离、低速传输具有优势。 超宽带（UWB）技术最初是面向雷达应用来开发的，一般认为它属于一种无载波通信技术。2002 年 2 月，美国联邦通信委员会（FCC）正式将其解禁

3、。目前超宽带（UWB）技术正被整合进家庭影院和便携式产品，主要用于视频和音频信号的无线发送。宽带（UWB）自问世后一直被看作是蓝牙技术的替代品，与其他无线技术如 WLAN 、蓝牙等相比，超宽带（UWB）具有低功耗、高带宽、低复杂度、低成本的优点，完全可以满足短距离家庭娱乐应用需求。 1.2 超宽带性能特点。超宽带无线通信是一种与传统技术有很大不同的无线通信技术。它能够实现无线局域网LAN 和个人区域网PAN 中无线接口的互联和接入。UWB具有以下特点： 1）抗干扰性能强 UWB信号，在发射时将微弱的无线电脉冲信号分散在宽阔的频带中，输出功率甚至低于普通设备产生的噪声。接收时将信号能量还原出来，

4、在解扩过程中产生扩频增益。因此，与 IEEE 802.11a、IEEE 802.11b 和蓝牙相比，在同等码速条件下，UWB具有更强的抗干扰性。 2）传输速率高 UWB 以非常宽的频率带宽来换取高速的数据传输，并且不单独占用现在已经拥挤不堪的频率资源，而是共享其他无线技术使用的频带。其数据速率可以达到几十兆比特每秒到几百兆比特每秒，有望高于蓝牙100倍，也可以高于IEEE 802.11a和 IEEE 802.11b。 3）带宽极宽 UWB 使用的带宽在 1GHz 以上，高达几吉赫兹，并且可以和目前的窄带通信系统同时工作而互不干扰。这在频率资源日益紧张的今天开辟了一种新的时域无线电资源。 4）频

5、谱利用率高，系统容量大 因为不需要产生正弦载波信号，可以直接发射冲激序列，因而 UWB系统具有很宽的频谱和很低的平均功率，有利于与其他系统共存，从而提高频谱利用率，带来了极大的系统容量。 5）功率低 UWB系统使用间歇的脉冲来发送数据，脉冲持续时间很短，一般在0.20ns1.5ns 之间，有很低的占空因数，系统耗电可以做到很低，在高速通信时系统的耗电量仅为几百 W几十 mw。同时由于 UWB系统信号的扩频处理增益比较大，即使采用低增益的全向天线发射，也可使用小于 1mW 的发射功率实现几千米的通信。 6）安全性好 UWB 安全性表现在两方面：一方面是采用跳时扩频，接收机只有已知发送端扩频码时才

6、能解出发射数据；另一方面是系统的发射功率谱密度极低。有用信息完全淹没在噪声中，被截获概率很小，被检测的概率也很低，用传统的接收机无法接收。 2 Wi-Fi 2.1 Wi-Fi技术简介 Wi-Fi（Wireless Fidelity,无线高保真）也是一种无线通信协议，正式名称是IEEE802.11b。 Wi-Fi 是以太网的一种无线扩展，Wi-Fi 网络可以使用来互连电脑链接上互连网。Wi-Fi 网络在无执照的 2.4 和 5 千兆 Hz 的无线电频带经营，数据速率可达 11Mbps（802.11b）54Mbps（802.11a），或包含以上两条频带的产品。理论上只要用户位于一个接入点四周的一定

7、区域内，就能以最高约 11Mb/s 的速度接入Web。但实际上，如果有多个用户同时通过一个点接入，带宽被多个用户分享。 由于 Wi-Fi 使用电波作为传送媒介， 资料包被截取的可能性高， 这成为用户所担心问题。现在 Wi-Fi 产品利用WED（Wired Equivalent Privacy）技术作资料加密之用。然而，其保密的效能却倍受质疑，支援新一代加密方式的 Wi-Fi 产品亦相继出现。虽然 Wi-Fi 在数据安全性方面比蓝牙技术要差一些，但在电波的覆盖范围方面却略胜一筹，可达 100 m 左右。 Wi-Fi 可以提供热点覆盖、低移动性和高数据传输速率， 无线接入和高速传输是Wi-Fi 技

8、术的主要特点。国内的电信、网通、移动都非常关注 Wi-Fi 技术的发展和应用。基于热点的接入服务曾经一度被看成是对3G的巨大冲击， 但Wi-Fi技术传输距离短和信号穿透能力差的特点同样也是不可克服的。 2.2 Wi-Fi技术的优势 近几年，WAP 的数量呈迅猛增长，无线网络的方便与高效使其得到迅速的普及。无论是无线城市的建设，还是企事业单位局域网的开通，还是手机的 Wi-Fi 功能，都与Wi-Fi 技术自身的优势是分不开的： 1）较广的局域网覆盖范围 基于蓝牙技术的电波覆盖范围非常小，半径大约只有 15m，而 Wi-Fi 的半径则可达100 m，可以覆盖整栋办公大楼； 2）传输速度快 Wi-F

9、i 技术传输速度非常快，可以达到 11Mbps（802.11b）或者 54Mbps （802.11a），适合高速数据传输的业务； 3）无需布线 Wi-Fi 最主要的优势在于不需要布线，可以不受布线条件的限制，因此非常适合移动办公用户的需要。在机场、车站、咖啡店、图书馆等人员较密集地方设置“热点” ，并通过高速线路将因特网接入上述场所。用户只要将支持无线 LAN的笔记本电脑或PDA拿到该区域内，即可高速接入因特网； 4）健康安全 IEEE802.11规定的发射功率不可超过 100 毫瓦，实际发射功率约 6070毫瓦，而手机的发射功率约 200毫瓦1瓦间，手持式对讲机高达5瓦。与后者相比，Wi-F

10、i 产品的辐射更小。 3 结论 每一种无线通信方式都有其独特之处，超宽带技术传输速率高，Wi-Fi 技术覆盖范围广。随着无线通信技术的发展，人们对高速短距离无线通信的要求越来越高，超宽带技术、Wi-Fi 技术都有着广泛的发展前景。UWB technology and other short-range wireless communications technology is comparedAs personal communication consumer electronics industry in the rapid development, short-range wireless

11、 communication field of all kinds of new skills ,art, new methods to emerge in endlessly, toward faster and more convenient and more safe and effective etc. The new technology in the development of the Intel access, information home appliances, mobile office, industrialization and other fields has b

12、een widely used. Among them, ultra-wideband (UWB) Wide Band, the mk-ultra technology is in after 1990s developed a kind of with high potential new wireless communication technology, it was listed as one of the ten future communication technology.1 uwb wireless communication 1.1 ultra-wideband techno

13、logy introduction UWB (the mk-ultra Wideband, ultra-wideband) technology is currently has been widely studied a new wireless communication technology, it has become a high-speed wireless personal nets (WPAN first choice of the technology. UWB refers to the signal bandwidth than 500MHz or is the sign

14、al bandwidth and center frequency ratio is more than 25% of communications technologies. With the common use of continuous carrier communication mode is different, use of UWB wireless signals center frequency 4.1 GHz, bandwidth of 1.4 GHz, spectral range is very wide, but transmission power is very

15、low. Communications speed in 250Kbit between 10Mbit/SEC. In 250Kbit/SEC transmission speeds can ensure as communication distance. In short (13m below) a has great advantage, highest transmission speed can reach 1Gb/S. While the traditional narrowband technology in long distance, low speed transmissi

16、on dominant.Ultra-wideband (UWB) technology is initially applied to develop the radar oriented, it is generally thought that it belongs to a kind of carrierless communications technologies. February 2002, the United States the FCC formally its suspension. Currently ultra-wideband (UWB) technology is

17、 being integrated into the family cinema and portable products, mainly used for video and audio signal of wireless transmission. Ultra-wideband (UWB) since when published has been regarded as bluetooth technology substitute, and other wireless technologies such as WLAN, bluetooth etc compared ultra-

18、wideband (UWB), with low power waste, high bandwidth and low complexity, the advantages of low cost, can completely satisfy short family entertainment application requirements. 1.2 ultra-wideband performance characteristics.Uwb wireless communication is a very different to the traditional technology

19、 of wireless communication technology. It can realize the wireless LAN LAN and personal regional network PAN wireless Internet and access interface. UWB has the following features:1) strong anti-jamming performance UWB signal, the launch will be weak radio pulse signal scattered on the broad band, o

20、utput power and even lower than ordinary equipment of the noise. Received will signal energy reduction out, in the solution enlarge produced during spread spectrum gain. Therefore, and IEEE 802.11 a, IEEE 802.11 b and bluetooth,compared to the same code speed conditions, the UWB has a strong anti-ja

21、mming.2) transmission rate is high UWB with very wide frequency bandwidth for high-speed data transmission, and not alone occupy now already crowded frequency resource, but sharing other wireless technology using frequency band. The data rate can reach dozens megabit per second to hundreds of megabi

22、t per second, is expected to 100 times higher than bluetooth, also can prep above IEEE 802.11a and IEEE 802.11b . 3) with very wide bandwidth UWB use of bandwidth in 1GHz above, up to a few ji hz and can and current narrowband communication system working at the same time and not interfere with each

23、 other. This in frequency resource of increasingly scarce today opened up a new time-domain radio resources. 4) spectrum is high efficiency, the system of large capacity Because it does not need to produce sine carrier signal that can be directly launch impulse sequence, thus ultra wideband (UWB) te

24、chnology has a wide spectrum and very low average power, which is beneficial to coexist with other systems, so as to improve the frequency spectrum utilization rate, which brings a lot of system capacity. 5) low power Ultra wideband (UWB) technology use intermittent pulses to send data, pulse lasted

25、 for a very short time, is in commonly 0.20 ns 1.5 ns between, have very low accounted for empty factor, the system power consumption can be done very low, in high speed communications system when consume only for hundreds of muon W dozens mW. At the same time because ultra wideband (UWB) technology

26、 of spread spectrum signal processing is relatively large, even if the gain USES low gain omni-directional antenna with emission, also can use less than 1mW launch power realization thousands of meters of communication. 6) good safety UWB safety performance in two aspects: one is to adopt the jump s

27、pread spectrum, receiver only known the sender spread spectrum yards to work out emission data; On the other hand is the transmission power spectral density is extremely low. Useful information completely submerged in noise, be intercept probability is small, be detection probability is low, with tr

28、aditional receiver cannot receive.2 Wi - Fi 2.1 Wi - Fi technology introduction Wi - Wireless Fidelity, Wireless Fi (high-fidelity) is a kind of Wireless communication protocol, official name is IEEE802.11 b. Wi - Fi is Ethernet a wireless expand, Wi - Fi network can use to interconnect computer lin

29、ks on the Internet. Wi - Fi network in no license 2.4 and 5 gigabit bandwidth management, Hz radio data rate can reach 11Mbps (802.11 b) 54Mbps (802.11 a), or include the above two bands of products. If the user is located in an access point theoretically around certain region, can with highest abou

30、t 11Mb/s faster access Web. But in fact, if there are multiple users at the same time through a point access, bandwidth by multiple users to share. Because Wi - Fi use waves as transmission medium, material package to be intercepted tall, this be the possibility of users are worried about problems.

31、Now Wi - Fi product use Wired Equivalent without (WED) technology data encryption purposes. However, its performance is highly confidential scepticism, support the new generation encryption method Wi - Fi products also arise. Although Wi - Fi in data security than bluetooth technology will send some

32、, but in waves coverage was slightly better, can amount to 100 m or so. Wi - Fi may provide hot coverage, low mobility and high speed of data transmission, wireless access and transmission with high speed is Wi - Fi technical main characteristics. Domestic telecommunication, CNC, mobile are very con

33、cerned Wi - Fi technology development and application. Based on the hotspot access service once considered the huge impact on 3G, but Wi - Fi technology transmission distance is short and signals penetrate the characteristics of poor ability also insurmountable. 2.2 Wi - Fi technical superiority In

34、recent years, the number of WAP at a rapid pace, wireless network convenience and efficient make its rapid popularization. Whether wireless urban construction, or business unit of LAN opening, or mobile phones Wi - Fi function, all with Wi - Fi technical advantages of itself is not divided: 1) wider LAN coverage Based on bluetooth radio coverage is very small, radius, and only about 15m Wi - Fi radius criterion of up to 100 m, can cover whole building office building, 2) transmission speed Wi - Fi technology transmission is very fast, can achieve 11Mbps (802.11 b) or 54Mbps (802