Overview of Short Range Wireless Communication Technology

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Overview of Short Range Wireless Communication Technology [Copy link]

1. Bluetooth
is applicable worldwide: Bluetooth works in the 2.4GHz ISM band. The ISM band range of most countries in the world is 2.4 to 2.4835GHz. It is not necessary to apply for a license from the radio resource management departments of each country to use this band.
It can transmit voice and data at the same time.
Temporary peer-to-peer connection. It is divided into master and slave devices in the network. Several Bluetooth devices can form a piconet (also known as a micro-net). Through time division multiplexing technology, a Bluetooth device can keep synchronization with different piconet at the same time. That is, it participates in a piconet at a certain moment and participates in another piconet at the next moment. It has
good anti-interference ability. Devices working in the ISM band include household microwave ovens, wireless local area networks WLAN, etc. In order to resist interference from these devices, Bluetooth uses frequency hopping to expand the spectrum, dividing the 2.402 to 2.48GHz band into 79 frequency points, with adjacent frequency points separated by 1MHz. After sending data at a certain frequency, the Bluetooth device jumps to another frequency to send data. The frequency arrangement order is pseudo-random, and the frequency changes 1600 times per second. Each frequency lasts for 625us.
Low power consumption. Bluetooth devices have four working modes under communication connection: activation, breathing, maintenance, and sleep. The activation mode is the normal working mode, and the other three are low-power modes stipulated for energy saving.
2. Wi-Fi (English: Wireless Fidelity) has
a wide radio wave coverage range. The radio wave coverage range based on Bluetooth is very small, with a radius of only about 15m, while Wi-Fi is up to 100m.
Fast transmission rate. Wi-Fi CERTIFIED ac certification breaks the gigabit rate barrier.
3. IrDA (English: Infrared Data Association)
does not need to apply for a license to use a specific frequency.
Small size and low power.
Point-to-point connection is used, and data transmission interference is small. The rate can reach 16Mbps.
Disadvantages: IrDA is line-of-sight transmission, and there must be no obstruction in the middle. And the infrared LED is not very durable.

4.ZigBee
has a low rate of 20 to 250kbps. It focuses on low transmission applications. The basic rate is 250kbps, which is reduced to 25kbps, and the transmission range can be expanded to 134m.
Low power consumption.
Large network capacity. ZigBee network can support up to 255 devices. That is, each device can connect to other 254 devices.
The effective range is small, between 10 and 75 meters, depending on the transmission power and application mode.
The working frequency band is flexible, and the frequency bands used are 2.4GHz, 868MHz (Europe), and 915MHz (USA), all of which are unlicensed bands. 5.The miniaturization and diversification of
RFID (English: Radio-frequency identification) electronic tags. Reusable electronic tags. 6.NFC (English: Near-field communication) is different from RFID. NFC uses two-way identification and connection, with an operating frequency of 13.56MHz and a working distance of within 20cm. Short distance and low energy consumption. Security. Close connection, private communication method. Compatible with existing contactless smart card technology. Low transmission rate. The NFC standard specifies three transmission rates, with the highest being only 424kbps. 7.UWB (English: Ultra Wide Band) Low power consumption, low interference, and high-speed transmission. Wireless carrier communication technology. It does not use a sinusoidal carrier, but uses nanosecond non-sinusoidal narrow pulses to transmit data, so it occupies a wide spectrum range. The US FCC stipulates that UWB occupies a bandwidth of more than 500MHz in the range of 3.1 to 10.6GHz. It uses low-power pulses to transmit data in a very wide spectrum range without causing significant interference to conventional narrowband wireless communication systems, and can make full use of spectrum resources. UWB is particularly suitable for transmitting large amounts of multimedia data in close proximity, and has the outstanding advantage of penetrating obstacles. 8. 60GHz With the widespread use of HDTV (high-definition television) and the massive interaction between personal handheld devices and computers, new wireless communication technologies must be studied to meet the requirements. These applications mainly provide wireless transmission with a transmission rate of several Gbps or even tens of Gbps in the range of 2 to 20m. 60GHz millimeter wave technology provides an effective means for this high-speed transmission. Unlike the well-known 802.11n (operating at 2.4GHz and 5GHz) and 802.11ac (operating at 5GHz band), 802.11ad operates at 60GHz band. The advantage of this band is that it has large bandwidth and no interference. 60Ghz technology can easily reach 7Gbps. In addition, 60GHz also has unmatched advantages in capacity and latency that other technologies cannot match. Of course, 60GHz also has its own weaknesses. We know that the higher the frequency band, the worse the ability to penetrate objects. 802.11ad operating at 60GHz band basically has no ability to penetrate walls. 9. Z-Wave Z-Wave is an emerging short-range wireless communication technology based on radio frequency, low cost, low power consumption, high reliability, and suitable for the network. Its operating frequency band is 868.42 (Europe) to 908.42MHz (USA), and it uses FSK (BFSK/GFSK) modulation. The effective coverage range of the signal is 30m indoors and more than 100m outdoors, which is suitable for narrowband applications. Z-Wave strongly promotes the development of low-speed wireless personal area networks (WPANs). Other short-range wireless communication technologies include HomeRF, wireless 1394, visible light communication, ad hoc (self-organizing network) technology, etc.