Short-range wireless communication technology detailed

With the continuous development of communication and information technology, the application of short-range wireless communication technology is accelerating, and it is becoming more and more mature. In general, as long as the communication between the two sides through radio waves transmission information and transmission distance limited to a shorter range (dozens of meters), can be called short-range wireless communication. At present, the short-range wireless technology we see has its own characteristics, or based on the specific requirements of transmission speed, distance, power consumption, or the expansion of functionality, or the specific requirements of some single application, or the differentiation of competitive technologies, but none of these technologies can be perfect enough to meet all the requirements, Here's what we'll look at today's short range wireless technologies:

Bluetooth technology

Bluetooth technology is a close-range wireless connection technology that is popular with the industry. It is an open global specification for wireless data and voice communications, which is based on Low-cost short-range wireless connectivity and provides low-cost access to fixed or mobile terminals. Bluetooth technology is a wireless data and voice communication of the open global norms, its essence is for fixed equipment or mobile devices in the communication environment to establish a common short-range wireless interface, communication technology and computer technology to further integrate, so that all kinds of equipment in the absence of wires or cables connected to each other, Can communicate or operate with each other in close range. Its transmission band for the global public General 2.4GHz ISM band, providing 1Mbps transmission rate and 10m transmission distance.

But the biggest obstacle to Bluetooth technology is that it's too expensive. Outstanding performance in chip size and price is difficult to cut down, anti-interference ability is not strong, transmission distance is too short, information security issues and so on. This makes many users unwilling to pay a large price for the wireless device. Therefore, industry experts believe that Bluetooth market prospects depend on the Bluetooth price and Bluetooth based applications can reach a certain scale.

Wi-Fi technology

Wi-Fi is a wireless extension of Ethernet, theoretically as long as users are located in a certain area around an access point. But in fact, if there are multiple users at the same time through a point of access, bandwidth is shared by multiple users, Wi-Fi connection speed will generally only hundreds of kb/s of the signal is not blocked by the wall, but the effective transmission distance within the building is less than outdoor.

The most promising applications for WLAN in the future will be in Soho, home wireless networks and buildings or places where cables are inconvenient to install. At present, the users of this technology are mainly from the airport, hotels, shopping malls and other public hotspot places. Wi-Fi technology can combine Wi-Fi with xml-based or Java Web Services, which can significantly reduce the cost of the enterprise. For example, companies choose to have 802.11b access points in each floor or department, instead of connecting the entire building with a cable line. As a result, it can save a lot of money to spend on laying cables.

IrDA Technology

IrDA is a technology that uses infrared to point-to-point communication, and is the first technology to realize wireless personal local area network (PAN). At present, its hardware and software technology is very mature, in small mobile devices, such as PDA, mobile phones are widely used. In fact, today every factory PDA and many mobile phones, laptops, printers and other products are supported by IrDA.

The main advantage of IrDA is that it is not required to use the frequency, so the infrared communication cost is low. It also has the characteristics of small volume, low power consumption, convenient connection and easy to use in mobile communication. In addition, the infrared emission angle is small, the transmission security is high. The disadvantage of IrDA is that it is a visual range transmission, the two communication devices must be aligned between the middle can not be separated from other objects, so the technology can only be used for 2 (not multiple) devices between the connection. Bluetooth does not have this limitation and is not blocked by walls. The current research direction of IrDA is how to solve the problem of line-of-sight transmission and improve the data transmission rate.

NFC Technology

NFC is a short-range wireless communication technology standard that is driven by Philips, Nokia and Sony and is similar to RFID (non-contact Radio frequency identification). Unlike RFID, NFC uses two-way recognition and connectivity. Work within the 20cm distance to the 13.56MHz frequency range. NFC was initially only a combination of remote identification and network technology, but has now developed into wireless connectivity technology. It can quickly and automatically set up wireless networks, providing a "virtual connection" for cellular devices, Bluetooth devices, and Wi-Fi devices, enabling electronic devices to communicate over a short range. NFC's short distance interaction greatly simplifies the entire authentication process, making access to electronic devices more direct, safer and clearer, without having to hear all kinds of electronic noises.

NFC helps to solve the problem of remembering multiple passwords by combining all the identity applications and services on a single device, while ensuring the security of the data. With NFC, a number of devices such as digital cameras, PDAs, set-top boxes, computers, mobile phones and other wireless interconnection between the exchange of data or services will be possible to achieve. Similarly, building Wi-Fi family wireless networks requires multiple computers, printers, and other devices with a wireless network card. In addition, there must be some skilled professionals to be competent for this work. Once NFC is placed in the access point, it is much easier to communicate with two of them than to configure Wi-Fi connectivity.

ZigBee Technology

The ZigBee is mainly applied between various electronic devices with short distance range and low data transmission rate. The ZigBee name comes from the way in which the swarm is used to survive and develop, and bees share information about the location, distance, and direction of newly discovered food sources by jumping zigzag-shaped dances.

ZigBee can be said to be Bluetooth with Shineti, it uses 2.4 GHz band, using frequency hopping technology. Compared with Bluetooth, ZigBee is simpler, slower, less power and less expensive. Its basic rate is 250kb/s, when reduced to 28kb/s, the transmission range can be extended to 134m, and obtain higher reliability. In addition, it can be networked with 254 nodes. Can better support gaming, consumer electronics, instrumentation and home automation applications than Bluetooth. It is expected to expand ZigBee applications in the fields of industrial monitoring, sensor networks, home monitoring, security systems and toys.

UWB Technology

UWB is a kind of wireless carrier communication technology, it does not use sine wave carrier, but the use of nanosecond sine wave narrow pulse transmission data, so it occupies a wide range of spectrum. UWB can transmit signals on very wide bandwidth, and the FCC's requirement for UWB is: to occupy more than 500MHz of bandwidth in the 3.1~10.6ghz band. Because UWB can use low power, low complexity transmitter/receiver to achieve high-speed data transmission, in recent years has been rapid development. It uses low-power pulses to transmit data in a very wide spectrum range without causing great interference to conventional narrowband wireless communication systems and making full use of spectrum resources. The high-speed data transceiver based on UWB technology has a wide range of applications.

UWB technology has the low complexity of system, transmit signal power spectral density is low, not sensitive to channel fading, low interception ability, high positioning precision, especially suitable for high speed wireless access in indoor and so on dense multipath place, it is very suitable for establishing an efficient wireless LAN or wireless domain network (WPAN). UWB is mainly used in small range, high resolution, can penetrate the walls, the ground and the body of radar and image systems. In addition, this new technology applies to LANs or pans with very high rate requirements (greater than MB/s).

With a certain degree of compatibility and high speed, the advantages of low cost and low power consumption make UWB more suitable for home wireless consumer market: UWB is especially suitable for high speed transmission of large amount of multimedia data and the outstanding advantages of penetrating obstacles, so many commercial companies consider it as a promising wireless communication technology, Applied to family situations such as sending a video signal from a set-top box wirelessly to a digital TV. Of course, the future of UWB also depends on the technology development of various wireless solutions, cost, user habits and market maturity and other factors.