What are the short-range wireless communication technologies?

Wireless communication technology has taken off in the market because it provides convenience and flexibility for electronic devices and networks, and its installation does not require expensive cables and wiring. Many industries such as military, industry, agriculture, and home appliances require the use of 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 that connects remote nodes within a very short distance. Short-range radio communication can minimize power consumption, volume, 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. This article defines short-range wireless communication technology as a system that provides wireless connectivity within a 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 that uses less power than WiFi. Bluetooth was originally designed for data transmission from personal computers to peripheral devices 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 uses GFSK, differential DQPSK or (8DPSK) frequency hopping spread spectrum for modulation. The total basic data rate for GFSK is 1mbit/s, DQPSK 2mbits/s and 3mbits/s. For 8DPSK, there are also 3 power levels: 0dBm (1mW), 4dBm (2.5mW) and 20dBm (100mW), which basically determines the standard distance of about ten meters, the maximum power is more than 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 of standards. It is commonly used in PC laptops and desktops, smart TVs, smartphones, drones, smart speakers, printers, and cars. The Wi-Fi frequency band has a fairly high absorption rate and is best suited for line-of-sight use. Many common obstacles, such as walls, household appliances, etc., may significantly reduce the range. However, it also helps reduce interference between different networks.

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

Wi-Fi embedded modules interoperate with any nearby base station and have 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 a more power-hungry protocol, making it an ideal choice for adding devices to an existing network. Just make sure that preparation plans include plenty of resources to manage multiple authentication setups 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 consumption and small digital radios that are cheaper 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, electric meters with home displays, and other devices that require short-range, low-rate wireless data transmission. In summary, Zigbee is a low-power, low-data-rate, short-range (i.e., personal area) wireless network.

The standard operates in the unlicensed ISM bands of 2.4 to 2.4835 GHz (global), 902 to 928 MHz (US and Australia), and 868 to 868.6 MHz (Europe). The 16 channels are allocated in the 2.4 GHz band, spaced 5 MHz apart, but each channel uses only 2 MHz of bandwidth. The 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, transmitting 2 bits per symbol.

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

4. Ultra-wideband

Ultra-wideband (UWB) is a short-range radio communication technology standard 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-range, 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 528-MHz wide channels. The data rate ranges from 53mbits/s to 480mbits/s. UWB mainly provides high-speed data connections for TVs, cameras, laptops, etc. Recent applications focus on sensor data collection, tracking applications, and precise positioning. Unlike spread spectrum, UWB's transmission method does not affect traditional narrowband and carrier transmission within the same frequency band.

5. Infrared (IR)

Infrared wireless uses low-frequency, invisible light to connect instead of 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. The light waves are usually modulated with a high-frequency signal, which is then encoded and modulated for transmission.

IrDA is a separate data transmission standard. The Infrared Data Association maintains its specifications. Increased rates range from 9.6 to 115.2 kbits/s, including 4 mbits/s, 16 mbits/s, 96 mbits/s, 512 mbits/s to 1 gbit/s. New standards for 5 and 10 gbit/s rates are under development with a range of less than one meter.

IR has several major advantages. First, because it is light rather than radio waves, it is not susceptible to any form of radio interference. Second, its signal is difficult to intercept or spoof, so it is very secure.

The infrared spectrum 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. Radio frequency remote controls are 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. Multiple wireless standards use the 802.15.4 standard as the PHY/MAC basis.

The standard defines 3 basic frequency ranges. The most commonly used frequency band is the global 2.4GHz ISM band. The basic data rate is 250kbits/s. Another range is the 902-928MHZ ISM band in the United States (10 channels). 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 a widely used power level. The 20dBm level is used for long range applications with a typical range of no more than 10 meters.

7. IEEE802.22

The IEEE 802.22 standard, also known as the Wireless Regional Area Network (WRAN) standard, is one of the newest IEEE wireless standards. It is designed for use without a license on unused broadcast television channels, known as white spaces. The frequency range for a 6 MHz channel is 470 MHz to 698 MHz. However, the standard has not been universally adopted. White space radio uses proprietary protocols and wireless standards.

802.22 radios should meet stringent requirements and discover channels that are not being used because of potential interfering TV stations. The radios use frequency-agile circuits to scan unused channels and listen for potential interfering signals. Base stations communicate radially with users at multiple fixed locations to get 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 22mbits/s. The biggest advantage of 22 is that it uses both VHF and low-frequency UHF frequencies and can provide very long-distance connections. The maximum allowed effective isotropic radiated power (EIRP) is 4W, and the base station range is up to 100 kilometers (nearly 60 miles).

8. ISM band

The most commonly used ISM band is 2.4 to 2.483 GHz, which is used 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 openers 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 used primarily for similar applications and secure payment transactions. It has a maximum range of about 20 cm, with a typical connection distance of 4 to 5 cm. Such a short distance increases the security of the connection, which is also encrypted. Many smartphones have NFC capabilities, and the goal is to implement an NFC payment system that allows consumers to pay with the tap of their phones.

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

NFC is also used to read tags. Unpowered tags convert RF signals into DC power, providing application-specific information to the processor and memory. Many NFC transceiver chips are available 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-powered radio frequency signal to power a passive tag, which then reads the data stored in the tag's memory.

RFID tags are flat, cheap, small, and can be attached to anything that needs to be identified or monitored. In some applications, they have replaced 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. It was developed by ITEF and provides a method to transmit IPv4 and IPv6 Internet protocols over low power wireless mesh networks and point-to-point links. RFC4944 also allows the implementation of the Internet of Things on the smallest remote devices. The protocol provides encapsulation and header compression routines for 802.15.4 radios.

12. Z-wave

Z-wave is a short-range wireless mesh network technology that can accommodate up to 232 nodes. In the United States and Canada, the wireless transceiver operates in the ISM band (908.42MHz), but other frequencies are used according to national regulations. The modulation method is GFSK. Data rates include 9600 bits/second and 40 bits/second. In free space conditions, the distance can reach 30 meters. The range 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 an easy and low-cost addition to almost any new product and can also improve convenience, performance or marketing.

family

Home consumer electronics are full of wireless capabilities. Almost every entertainment product has an infrared remote control. Energy metering and accessory monitors, remote thermometers, wireless thermostats and other weather monitors, security systems, garage door openers, smart parking sensors also connect to wireless networks. Almost every home has a Wi-Fi connection.

Business

Wireless temperature and humidity monitoring, lighting controls, and wireless thermostats are commonly used in commercial applications. Some video surveillance cameras use wireless rather than coaxial cables. Mobile phone wireless payment systems are expected to revolutionize commerce.

industry

Wired connections in the industry are gradually being replaced by wireless. Remote monitoring of flow, humidity, temperature and pressure are common applications. Wireless control of robots, industrial processes and machine tools improves the convenience of industrial environments and promotes economic development. M2M technology opens the door to many applications such as car positioning (GPS) and monitoring vending machines. The Internet of Things is mainly wireless. Radio frequency identification technology makes 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 appropriate technologies can be selected for application according to specific needs.