Wireless communication technology has taken off in the market because it offers convenience and flexibility for electronic devices and networks, and its installation does not require expensive cables and wiring. Military, industrial, agricultural, home appliances and many other industries all need to use wireless communication technology. Each industry requires different technical characteristics due to its use and environment.

Short-range wireless communication technology

Short-range wireless communication technology is a network protocol in which remote nodes are connected over extremely short distances. Short-range radio communications can minimize power consumption, size, heat, and cost. It also has a wide range of scenarios, technologies, and requirements, making it an ideal solution for commercial building automation, high-density greenhouse sensing, and residential energy monitoring. Most are implemented in the form of small, low-cost ICs or complete plug-in modules. In this article, short-range wireless communication technology is defined as a system that provides wireless connectivity within the local interaction range and classifies it into the following types.

1. Bluetooth

Bluetooth is a short-range wireless communication technology based on the IEEE802.5.1 standard, which consumes less power than WiFi. Bluetooth was originally designed for data transmission from a personal computer to peripherals such as mice, keyboards, printers, mobile phones, headsets, personal digital assistants, etc. For these types of applications, Bluetooth is called WPAN (Wireless Personal Area Network). Bluetooth uses a star network topology, allowing a simple network of up to seven devices to communicate with a single access point.

Bluetooth operates in the 2.4Hz ISM band and is modulated using GFSK, differential DQPSK, or (8DPSK) frequency hopping spread spectrum. The total basic data rate of GFSK is 1mbit/s, DQPSK2mbits/s and 3mbits/s For 8DPSK, there are also 3 power levels: 0dBm (1mW), 4dBm (2.5mW) and 20dBm (100mW), which basically determines that the standard distance is around ten meters, the maximum power is above 100 meters, and the path is clear.

2、Wi-fi

Wi-Fi is a short-range wireless communication technology based on the IEEE802.11 series standards. It is commonly used in PCs, laptops and desktops, smart TVs, smartphones, drones, smart speakers, printers, and cars. The Wi-Fi band has a fairly high absorption rate and is best suited for line-of-sight use. Many common obstacles, such as walls, home appliances, etc., can be greatly reduced. However, it also helps to reduce interference between different networks.

IEEE802.11a operates at 5GHz and has a maximum data rate of 54Mbps. The IEEE802.11b and IEEE802.11g operate at 2.4GHz and have a maximum data transmission rate of 11Mbps and 54Mbps, respectively. In addition, there are several different wireless frequency ranges available for WiFi communication: the 900MHz, 2.4GHz, 5GHz, 5.9GHz, and 60GHz bands. Each range is divided into multiple channels. Each country has its own rules on the channels that are allowed. The ISM band range is also widely used.

The Wi-Fi embedded module is interoperable with any nearby base station and has a standard Wi-Fi range of up to 300 feet and high throughput. This partially offsets the additional configuration complexity of Wi-Fi and the additional cost of more power-hungry protocols, making it ideal for adding devices to existing networks. Just make sure that your preparation plan includes a lot of resources to manage multiple authentication settings over the long term.

3、ZigBee

ZigBee is a short-range wireless communication protocol based on IEEE802.15.4. It is used to create PANs with low-power and small digital radios that are less expensive than other wireless personal area networks (WPANs) such as Bluetooth or Wi-Fi and can be used for home automation and medical device data collection. Applications include traffic management systems, wireless light switches, electricity meters with home displays, and other devices that require short-range, low-rate wireless data transmission. To sum up, Zigbee is a low-power, low-data-rate, short-range (i.e., personal area) wireless network.

The standard operates in the license-free ISM bands of 2.4 to 2.4835 GHz (worldwide), 902 to 928 MHz (US and Australia), and 868 to 868.6 MHz (Europe). The 16 channels are allocated in the 2.4GHz band with 5MHz spacing, but each channel uses only 2MHz bandwidth. This radio uses direct sequence spread spectrum coding. The digital stream manages it into the modulator. BPSK operates in the 868 and 915 MHz bands, and OQPSK operates in the 2.4 GHz band, with 2 bits per symbol transmitted.

The original wireless data rate for the 2.4GHz band is 250 kbit/s per channel, 40 kbit/s per channel for the 915 MHz band, and 20 kbit/s per channel for the 868 MHz band. For indoor applications, the 2.4GHz transmission range is 10-20 meters.

4. Ultra-wideband

Ultra-wideband (UWB) is a technical standard for short-range radiocommunications defined by the WiMedia Alliance. IT CAN USE ULTRA-LOW POWER CONSUMPTION TO AVOID INTERFERENCE IN THE SPECIFIED FREQUENCY BAND OF 3.1~10.6GHZ FOR SHORT-DISTANCE AND HIGH-BANDWIDTH COMMUNICATION. The maximum communication distance is about ten meters. In most applications, the range is less than a few meters. The frequency band is divided into multiple channels with a width of 528-MHz. Data rates range from 53 Mbits/s to 480 Mbits/s. UWB mainly provides high-speed data connections for TVs, cameras, laptops, etc. Recent applications have focused on sensor data collection, tracking applications, and precise positioning. Unlike spread spectrum, UWB does not affect the transmission of carriers in the traditional narrowband and the same frequency band.

5. Infrared (IR)

Infrared wireless uses a low-frequency, invisible light connection instead of a radio. The main wavelength range is 850~940μm. The transmitter uses an infrared light-emitting diode, and the receiver uses a diode photodetector and amplifier. Light waves are usually modulated with high-frequency signals, which are then encoded and modulated for transmission.

IrDA is a separate data transmission standard. The Infrared Data Association maintains its specifications. The increase rate range is 9.6~115.2kbits/s, including 4Mbits/s, 16Mbits/s, 96Mbits/s, and 512Mbits/s~1Gbit/s. New standards for 5 and 10 Gbit/s rates are being developed with a range of less than one meter.

IR has several major advantages. First of all, since it is light and not radio waves, it is not susceptible to any form of radio interference. Second, its signal is difficult to intercept or spoof, so it is highly secure.

Infrared spectroscopy was once widely used in printers, laptops, and cameras. It has been largely replaced by Bluetooth, Wi-Fi, and other short-range wireless communication technologies. At present, RF remote control is still commonly used in consumer remote controls.

6、IEEE802.15.4

IEEE802.15.4 was created to support point-to-point links and wireless sensor networks. Many wireless standards use the 802.15.4 standard as the PHY/MAC basis

The standard defines 3 fundamental frequency distances. The most commonly used frequency band is the global 2.4GHz ISM band. The base data rate is 250kbits/s. THE OTHER RANGE IS THE USA 902-928 MHZISM BAND (CHANNEL 10). The data rate is 40kbits/s or 250kbits/s.

All 3 ranges use DSSS modulation with BPSK or offset QPSK. The minimum defined power level is -3dBm (0.5mW). 0dBm is the widely used power level. The 20dBm level is used for remote applications with a typical range of no more than 10 meters.

7、IEEE802.22

The IEEE802.22 standard, also known as the Wireless Area Network (WRAN) standard, is one of the latest IEEE wireless standards. It is designed to be used without permission on unused broadcast television channels, known as white space. THE FREQUENCY RANGE OF THE 6MHZ CHANNEL IS 470MHZ TO 698MHZ. However, this standard has not yet been universally adopted. Blank radios use proprietary protocols and wireless standards.

802.22 radios should meet strict requirements and discover channels that are not in use due to potential interference with television stations. Radios use frequency-flexible circuitry to scan for unused channels and listen for potential interfering signals. Base stations communicate radially with users in multiple fixed locations to gain Internet access or other services.

The standard provides sufficient spectral efficiency to meet the needs of multiple user channels, with download speeds of up to 1.5Mbit/s and upload speeds of up to 384kbit/s. The maximum data rate per 6MHz channel is between 18 and 22 Mbits/s. The biggest advantage of the 22 is that it uses both VHF and low-frequency UHF frequencies and can provide connections over very long distances. The maximum permissible effective isotropically radiated power (EIRP) is 4W, and the base station has a range of up to 100 km (nearly 60 miles).

8. ISM frequency band

The most commonly used ISM band is 2.4 to 2.483GHz for Wi-Fi, cordless phones, Bluetooth, 802.15.4 radios, etc. The second most popular band is the 902-928-MHz band.

Other widely used ISM frequencies include 315MHz for RKE applications and garage door opening, and 433MHz for remote temperature monitoring. Other less commonly used frequencies are 13.56MHz, 27MHz, and 72MHz.

9. Near-field communication

Near-field communication (NFC) is an ultra-short-range wireless communication technology that is primarily used for similar applications and secure payment transactions. It has a maximum range of about 20 centimeters and a typical attachment distance of 4 to 5 centimeters. Such a short distance increases the security of the connection, and the security of the connection is also encrypted. Many smartphones are NFC-enabled, with the goal of enabling an NFC payment system that allows consumers to tap and pay with their mobile phones.

NFC uses an ISM management frequency of 13.56MHz. At this lower frequency, the transmitting loop antenna and the receiving loop antenna. The transmission is carried out by the magnetic field of the signal rather than the accompanying electric field.

NFC is also used to read tags. The powerless tag converts the RF signal into DC power, providing application-specific information to the processor and memory. Many NFC transceiver chips can be used to enable new applications, and multiple standards exist.

10. Radio frequency identification

Radio Frequency Identification (RFID) is primarily used to identify, locate, track, and manage inventory. A nearby reader sends a high-power RF signal to power the passive tag and then reads the data stored in the tag's memory.

RFID tags are flat, cheap, and small, and can be attached to anything that needs to be identified or monitored. In some applications, they replace barcodes. RFID uses the ISM frequency of 13.56MHz, but other frequencies are also used, including 125kHz, 134.5kHz, and frequencies in the 902-928MHz range. Various ISO/IEC standards exist.

11、6 LoWPAN

6 LoWPAN refers to the IPv6 protocol in low-power wireless PAN. Developed by ITEF, it provides a way to transmit IPv4 and IPv6 Internet protocols over a low-power wireless mesh network and point-to-point links. RFC4944 also allows IoT to be implemented on the smallest remote device. This protocol provides encapsulation and header compression routines for 802.15.4 radios.

12、Z-wave

Z-wave is a short-range wireless mesh networking technology that can accommodate up to 232 nodes. In the U.S. and Canada, wireless transceivers operate in the ISM band (908.42MHz), but use other frequencies according to national regulations. The modulation mode is GFSK. Data rates include 9600 bits/sec and 40 bits/sec. In free space conditions, distances of up to 30 meters are possible. The range of penetration through walls is much shorter. The main applications of Z-wave are thermostats, door locks, home automation, lighting, smoke detectors, security and other home appliances.

Typical applications of short-range wireless communication technology

Wireless is a simple and low-cost addition to almost all new products, and it can also improve convenience, performance, or marketing.

Family

Home consumer electronics are packed with wireless capabilities. Almost all entertainment products have infrared remote controls. Energy metering and accessories monitors, remote thermometers, wireless thermostats and other weather monitors, security systems, garage door openers, smart parking sensors are also connected to wireless networks. Almost every home has a Wi-Fi connection.

commerce

Wireless temperature and humidity monitoring, lighting control, and wireless thermostats are commonly used in commercial applications. Some video surveillance cameras use wireless instead of coaxial cables. Mobile wireless payment systems are poised to revolutionize business.

industry

Wired connectivity in the industry is gradually being replaced by wireless. Remote monitoring of flow, humidity, temperature, and pressure is a common application. Wireless control of robots, industrial processes, and machine tools improves the convenience of industrial environments and boosts economic development. M2M technology opens the door to many applications such as car positioning (GPS) and monitoring vending machines. The Internet of Things is primarily wireless. Radio Frequency Identification (RFID) technology has made it easier to track and locate almost anything.

In short, these short-range wireless communication technologies have their own advantages and characteristics in different application scenarios, and the appropriate technology can be selected for application according to specific needs.