Uwb wireless communication is a very different to the traditional technology 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, output 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-jamming。

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 megabit 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 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) technology 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 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 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 spread 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 traditional receiver cannot receive。

4。2 Wi - Fi 

4。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 links 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 about 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。 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, but in waves coverage was slightly better, can amount to 100 m or so。