What do you mean by UWB?

UWB technology is a new kind of wireless communication technology. It is directly modulated by impulse pulses with very steep rise and fall times, so that the signal has a GHz magnitude of bandwidth. Ultra-wideband technology solves the major problems of communication, which is not sensitive to channel fading, low power spectral density, low interception capability, low system complexity, and can provide several centimeters of positioning accuracy.

The advantages of UWB

Compared with other wireless communication technologies, UWB has many advantages. Table 1 compares UWB technology with other WLAN technologies. The characteristics of UWB technology are: high transmission rate, large system capacity, strong resistance to multipath, low power consumption and low cost. UWB transmits information by altering the amplitude, spacing, or duration of the pulse. Compared with narrowband transceiver and Bluetooth transceiver, UWB does not need to produce sinusoidal carrier signal, it can directly transmit impulse pulse sequence, so it has wide spectrum and low average power, which is advantageous to coexist with other systems and improve spectrum utilization.

UWB does not need sine wave modulation and up and down frequency, also do not need local oscillator, amplifier and mixer, so small size, the structure of the system is relatively simple. UWB signal processing is also relatively simple, just use a few RF or microwave devices, RF design simple, the system's frequency adaptive ability. Pulse transmitter and receiver can be integrated into a chip, plus time base and controller, can constitute a UWB communication equipment. As a result, its cost can be greatly reduced.

Because the UWB signal uses the jump-time spread spectrum, its RF bandwidth can reach more than 1GHz, its emission power spectral density is very low, the signal hidden in the ambient noise and other signals, with the traditional receiver can not receive and identify, must be consistent with the beginning of the spread spectrum code pulse sequence can be demodulation, so increased the security of the system.

The fading of UWB signal is relatively low, and it has strong ability to resist multipath fading. The high bandwidth of UWB signal brings the enormous system capacity, because the UWB radio signal emission impulse pulse duty ratio is very low, the system has high gain and strong multipath resolution, so the system capacity is higher than other wireless technology.

Because the UWB signal spread spectrum processing gain is quite large, even if uses the low gain omni-direction antenna, may use the transmit power less than 1mW to realize several kilometers of communication. Such low transmission power prolongs the time of system power supply and is very suitable for the application of mobile communication equipment. Research has shown that the use of UWB mobile phone standby time can be up to 6 months, and low radiation power can avoid excessive electromagnetic radiation on the human body damage.

The application of Uwb-rt

With the beginning of commercialization of UWB-RT, this technology provides the possibility for the deployment of short-range wireless communication systems that support high-speed applications and low-speed smart devices. The UWB antenna system defined by FCC, using simple modulation and coding mechanism, can reach the information rate more than 100mb/s in a short distance. UWB can make a tradeoff between the information rate and the coverage range.

A large number of applications are suitable for using UWB, including: High-speed wireless personal network (HDR-WPAN), Wireless Ethernet Interface Link (WEIL), smart antenna Area network (IWAN), outdoor Point-to-Point Network (OPPN), sensor, positioning and identification Network (SPIN).

The first three scenarios assume that the network of UWB devices is deployed in residential or office areas, mainly for the transmission of wireless video/audio and control signals for entertainment. The fourth situation provides an outdoor point-to-point connection, while the fifth considers industrial and commercial environments.

1. High-speed wireless personal network (Hdr-wpan)

Hdr-wpan is defined as: the active device of each room is 5~10, in 1~10m range, the data rate is 100~500mb/s, mainly based on point-to-point topology. Use existing wired or wireless standards to connect to the outside by relaying.

2. Wireless Ethernet Interface Link (WEIL)

You can extend the concept of HDR to a higher data rate, such as 1gb/s,2.5gb/s. Weil should meet the following requirements: from the PC manufacturer, the need for an alternative Ethernet line, from the consumer point of view, between the PC and LCD screen requirements for high-quality wireless video transmission capabilities, can transmit wireless digital video.

3. Smart Antenna Area Network (IWAN)

Iwan is characterized by: in the room or office where there is high-density equipment, the coverage is 30m. The requirements of the equipment are: low cost,

Low power consumption, such as 1~10MW, to provide users with home/Office intelligent Distribution network. Equipment Features: Accurate positioning, tracking, support environment-sensitive equipment, in the current narrow-band short distance network is not easy to achieve. In this case, a wireless last mile or an available connection to the outside can be used to send alarms, control signals, or to remotely check the status of sensors around the home.

4. Outdoor point to Point Network (OPPN)

UWB devices are deployed outdoors, mainly for PDA uplink and information exchange, news text, pictures and video downloads. Which criteria will determine whether the OPPN structure uses centralized or distributed, is a subject that needs further study.

The forthcoming UWB standards in Europe will severely limit the deployment of UWB devices that support outdoor use. This may change, however, as the use of UWB controls will continue to improve, as other wireless services have experienced in the past.

5. Sensor, positioning and identification Network (SPIN)

Spin system features: High density of equipment, hundreds of of each layer, mainly in the factory or warehouse, send a low speed packet with positioning information. Spin equipment use a large range, if the main from the topology, between the individual equipment and the main station up to 100m. In industrial applications, spin requires advanced link reliability and adaptive system characteristics to respond to dynamically changing interfaces and propagation environments.

UWB will play an important role is: according to the needs of users to provide effective business. The division of scene mechanism and the development of various networks, including the above analysis of various situations, is far from meeting the expectations of users. A grand goal is to achieve seamless coexistence and interoperability of various networks in different scenarios. Therefore, the design of effective connection, automatic roaming mechanism and data link adaptive, is an important research topic in the future.