# Moving Ad Hoc Networks--A Comparative Study
## 7 Comparison of Short and Long-Distance Wireless Communication Technologies  
Wireless communication is a communication method that uses the characteristics of electromagnetic wave signals to propagate in free space for information exchange. Wireless communication technology itself has many advantages and a low cost; wireless communication technology does not need to establish physical lines, let alone using a large amount of manpower to lay cables. Wireless communication technology is not restricted by the industrial environment, and it has a strong ability to resist changes in the environment. The common wireless communication (data) transmission methods and technologies are divided into two types: \"Short-distance wireless communication technology\" and \"long-distance wireless transmission technology\". 1. Short distance wireless transmission technology. Short distance wireless communication technology means that both parties in the communication transmit data through radio waves, the transmission distance is within a relatively short range, and its application range is very wide. In recent years, the short-range wireless communication standards that are widely used and have good development prospects include Zig-Bee, Bluetooth, wireless broadband (Wi-Fi), ultra-wideband (UWB), and near field communication (NFC). * Zig-Bee is a short-distance, low-power wireless communication technology based on the IEEE802.15.4 standard. Zig-Bee comes from the communication method of the bee colony. The bee (Bee) relies on flying and buzzing (Zig) to shake its wings to determine the direction, location, and distance of the food source with its companions. However, it is characterized by a short distance, and its usual transmission distance is 10-100 m. However, it requires low power consumption. * Bluetooth can realize point-to-point or point-to-multipoint wireless data and sound transmission within a radius of 10 m, and its data transmission bandwidth can reach 1 Mbps. The communication medium is a frequency between 2.402 GHz and 2.480 GHz Electromagnetic waves. Wireless broadband (Wi-Fi) is a wireless LAN access technology based on the 802.11 protocol. The outstanding advantage of (Wi-Fi) technology is that it has a wider local area network coverage, and its coverage radius can reach about 100 m. Compared with Bluetooth technology, Wi-Fi has a wider coverage area; the transmission speed is very fast. The transmission speed can reach 11 Mbps (802.11.b) or 54 Mbps (802.11.a), which is suitable for high-speed data transmission services. * Ultra-wideband (UWB) is a non-carrier communication technology that uses nanosecond to picosecond non-sine wave narrow pulses to transmit data. The transmission distance is usually within 10 M, using a bandwidth above 1 GHz, and the communication speed can be up to several hundred megabits/s or more. UWB's working frequency range ranges from 3.1 GHz to 10.6 GHz, and the minimum working bandwidth is 500 MHz. * NFC is a new short-range wireless communication technology with a working frequency of 13.56 MHz. It was developed from 13.56 MHz radio frequency identification (RFID) technology. NFC uses Amplitude Shift Keying (ASK) modulation, and its data transmission rate is generally 106 kbit/s and 424 kbit/s. The main advantages of NFC are its short distance, high bandwidth, low energy consumption, compatibility with non-contact smart card technology, and broad application value in fields such as access control, public transportation, and mobile payment. 2. Long-distance wireless transmission technology. At present, the wireless communication technologies widely used in remote areas mainly include, DSRC, WiMAX, GPRS/CDMA, digital radio, spread spectrum microwaves, wireless network bridges, satellite communication, and shortwave communication technology, etc. * Digital radio communication is a wireless data transmission station that adopts digital signal processing, digital modulation and demodulation, forward error correction, equalization soft decision, and other functions.