With the continuous development of communication and information technology, the application pace of short-distance wireless communication technology continues to accelerate and is becoming increasingly mature. In a general sense, as long as the communication sender and receiver transmit information through radio waves and the transmission distance is limited to a short range (tens of meters), it can be called short-distance wireless communication. The short-range wireless technologies we have seen so far all have their own unique characteristics, or are based on special requirements for transmission speed, distance, and power consumption; or focus on the scalability of functions; or meet the special requirements of some single applications; or Establish competitive technology differentiation, etc., but no technology can be perfect enough to meet all needs. Let’s review the current short-range wireless technologies:

Bluetooth technology

Bluetooth technology is a short-range wireless connection technology that has attracted widespread attention in the industry. It is an open global specification for wireless data and voice communications. It is based on low-cost short-distance wireless connections and can provide cheap access services for fixed or mobile terminal devices. Bluetooth technology is an open global specification for wireless data and voice communications. Its essence is to establish a universal short-range wireless interface for the communication environment between fixed devices or mobile devices, and further combine communication technology with computer technology to enable Various devices can communicate or operate with each other at close range without wires or cables connecting each other. Its transmission frequency band is the 2.4GHz ISM frequency band commonly used by the global public, providing a transmission rate of 1Mbps and a transmission distance of 10m.

But the biggest obstacle encountered by Bluetooth technology is that it is too expensive. Prominent manifestations include the difficulty in reducing chip size and price, weak anti-interference ability, too short transmission distance, information security issues, etc. This makes many users unwilling to spend a lot of money to purchase such wireless devices. Therefore, industry experts believe that the market prospects of Bluetooth depend on the price of Bluetooth and whether Bluetooth-based applications can reach a certain scale.

Wi-Fi technology

Wi-Fi is a wireless extension of Ethernet. In theory, as long as the user is located within a certain area around an access point. But in fact, if there are multiple users accessing through one point at the same time and the bandwidth is shared by multiple users, the Wi-Fi connection speed will generally be only a few hundred kb/s. The signal is not blocked by walls, but inside the building The effective transmission distance is smaller than outdoors.

The most potential applications of WLAN in the future will be mainly in SOHO, home wireless networks, and buildings or places where it is inconvenient to install cables. Currently, users of this technology mainly come from public hotspots such as airports, hotels, and shopping malls. Wi-Fi technology can integrate Wi-Fi with XML or Java-based Web services, which can significantly reduce enterprise costs. For example, enterprises choose to equip each floor or department with 802.11b access points instead of using cables to connect the entire building. This saves a lot of money on laying cables.

IrDA technology

IrDA is a technology that uses infrared rays for point-to-point communication and is the first technology to implement wireless personal area networks (PAN). At present, its software and hardware technologies are very mature and are widely used in small mobile devices, such as PDAs and mobile phones. In fact, every PDA shipped today and many mobile phones, laptops, printers and other products support IrDA.

The main advantage of IrDA is that there is no need to apply for the right to use the frequency, so the cost of infrared communication is low. It also has the characteristics of small size, low power consumption, convenient connection, and simplicity and ease of use required for mobile communications. In addition, the infrared emission angle is small and the transmission security is high. The disadvantage of IrDA is that it is a line-of-sight transmission. Two devices communicating with each other must be aligned and cannot be blocked by other objects. Therefore, this technology can only be used for connections between two (not multiple) devices. . 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 similar to RFID (contactless radio frequency identification) promoted by Philips, NOKIA and Sony. Unlike RFID, NFC uses two-way identification and connection. Works in the 13.56MHz frequency range within a distance of 20cm.

NFC was originally just a merger of remote control identification and network technology, but now it has developed into a wireless connection technology. It can quickly and automatically establish a wireless network, providing a "virtual connection" for cellular devices, Bluetooth devices, and Wi-Fi devices, allowing electronic devices to communicate over short distances. The short-distance interaction of NFC greatly simplifies the entire authentication and identification process, making mutual access between electronic devices more direct, safer and clearer, without having to hear various electronic noises.

NFC helps solve the trouble of remembering multiple passwords by combining all identity recognition applications and services on a single device, while also ensuring data security protection. With NFC, it will be possible to wirelessly interconnect multiple devices such as digital cameras, PDAs, set-top boxes, computers, mobile phones, etc. to exchange data or services with each other. Similarly, building a Wi-Fi family wireless network requires multiple computers, printers and other devices with wireless network cards. In addition, professionals with certain skills are required to be qualified for this job. After NFC is placed in the access point, communication can be achieved by simply bringing two of them close to each other, which is much easier than configuring a Wi-Fi connection.

ZigBee technology

ZigBee is mainly used between various electronic devices within short distances and with low data transmission rates. The name ZigBee comes from the communication method used by bees to survive and develop. Bees share information such as the location, distance and direction of newly discovered food sources by dancing a ZigZag-shaped dance.

ZigBee can be said to be the brother of Bluetooth. It uses the 2.4 GHz band and adopts frequency hopping technology. Compared with Bluetooth, ZigBee is simpler, slower, and has lower power and cost. Its basic rate is 250kb/s. When reduced to 28kb/s, the transmission range can be expanded to 134m and achieve higher reliability. Additionally, it can be networked with 254 nodes. Can support gaming, consumer electronics, instrumentation and home automation applications better than Bluetooth. People expect to expand ZigBee applications in areas such as industrial monitoring, sensor networks, home monitoring, security systems and toys.

UWB technology

Ultra-wideband technology UWB is a wireless carrier communication technology. It does not use sinusoidal carrier waves, but uses nanosecond-level non-sinusoidal narrow pulses to transmit data. Therefore The frequency spectrum it occupies is very wide. UWB can transmit signals over a very wide bandwidth. The U.S. FCC's regulations for UWB are: occupying more than 500MHz of bandwidth in the 3.1-10.6GHz frequency band. Because UWB can utilize low-power, low-complexity transmitter/receivers to achieve high-speed data transmission, it has developed rapidly in recent years. It uses low-power pulses to transmit data within a very wide spectrum range without causing major interference to conventional narrowband wireless communication systems, and can make full use of spectrum resources. High-rate data transceivers built based on UWB technology have a wide range of uses.

UWB technology has the advantages of low system complexity, low transmit signal power spectrum density, insensitivity to channel fading, low interception capability, and high positioning accuracy. It is especially suitable for high-speed wireless access in dense multipath places such as indoors. It is ideal for building an efficient wireless LAN or wireless personal area network (WPAN). UWB is mainly used in radar and imaging systems with small range, high resolution, and ability to penetrate walls, floors and bodies. In addition, this new technology is suitable for LANs or PANs that require very high speeds (greater than 100 Mb/s).

The advantages of certain compatibility, high speed, low cost and low power consumption make UWB more suitable for the needs of the home wireless consumer market: UWB is especially suitable for transmitting large amounts of multimedia data at high speed within short distances and can penetrate obstacles. The outstanding advantages of wireless communication have led many commercial companies to regard it as a promising wireless communication technology, which can be used in home situations such as wirelessly transmitting video signals from set-top boxes to digital TVs. Of course, the future future of UWB also depends on many factors such as the technological development, cost, user habits and market maturity of various wireless solutions.

RFID technology

RFID radio frequency identification is a non-contact automatic identification technology. It automatically identifies target objects and obtains relevant data through radio frequency signals. The identification work does not require manual intervention and can Work in various harsh environments. RFID technology can identify high-speed moving objects and identify multiple tags at the same time, making the operation quick and convenient.

RFID electronic tags are a breakthrough technology: "First, it can identify a single, very specific object, instead of only identifying one type of object like a barcode; second, it uses radio frequency , data can be read through external materials, while barcodes must rely on lasers to read information; thirdly, multiple objects can be read at the same time, while barcodes can only be read one by one. In addition, the amount of information stored is also very large. Big."