Comparison of three common wireless network access technologies

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Comparison of three common wireless network access technologies [Copy link]

　1. IEEE802.11 Family

　　IEEE802.11 is a wireless LAN standard originally formulated by IEEE. It is mainly used to solve the wireless access between users and user terminals in office LAN and campus network. The service is mainly limited to data access, and the maximum rate can only reach 2Mb/s. At present, companies such as 3Com have wireless network cards based on this standard .

　　Since IEEE802.11 cannot meet people's needs in terms of rate and transmission distance, the IEEE group has successively launched two new standards, IEEE802.11b and IEEE802.11a. The main technical differences between the three are in the MAC sublayer and the physical layer.

　　The IEEE802.11b physical layer supports two new rates of 5.5Mb/s and 11Mb/s. The IEEE802.11 standard is an 11-bit modulation chip when spreading the spectrum, while the IEEE802.11b standard uses a new modulation technology CCK to complete. IEEE802.11b uses dynamic rate drift, and can switch between 11Mb/s, 5.5Mb/s, 2Mb/s, and 1Mb/s due to environmental changes, and is compatible with IEEE802.11 at 2Mb/s and 1Mb/s.

　　IEEE802.11a operates in the 5GHz U-NII band, with a physical layer rate of up to 54Mb/s and a transport layer rate of 25Mb/s. It uses a unique spread spectrum technology of orthogonal frequency division multiplexing (OFDM); it can provide a 25Mb/s wireless ATM interface and a 10Mb/s Ethernet wireless frame structure interface, as well as a TDD/TDMA air interface; it supports voice, data, and image services; one sector can access multiple users, and each user can carry multiple user terminals. However, the chip has not entered the market, the equipment is expensive, the air relay is not good, the point-to-point connection is very uneconomical, and it is not suitable for small devices. Fortunately, Radiata's low-cost COMS wireless engine chip device can support IEEE802.11a.

　　

　　2. Bluetooth Upstart

　　Bluetooth (IEEE802.15) is a new standard. For IEEE802.11, it is not for competition but for mutual complementation. Bluetooth is more mobile than IEEE802.11 . For example, IEEE802.11 is limited to offices and campuses, while Bluetooth can connect a device to LAN and WAN, and even supports global roaming. In addition, Bluetooth is low-cost and small in size, and can be used for more devices. However, Bluetooth is mainly a point-to-point short-range wireless transmission technology, which is either RF or infrared in nature. Moreover, Bluetooth is designed for low-power, short-range, and low-bandwidth applications. Strictly speaking, it is not a true LAN technology.

　　

　　3. HomeRF for home networks HomeRF

　　is mainly designed for home networks. It is a combination of IEEE802.11 and DECT, aiming to reduce voice data costs. HomeRF also uses spread spectrum technology, works in the 2.4GHz frequency band, and can simultaneously support 4 high-quality voice channels. However, the current transmission rate of HomeRF is only 1~2Mb/s. FCC recommends increasing it to 10Mb/s.

　　Through comparative analysis, we can see that various standards are formulated based on different usage scenarios and different user needs. Some are for increasing bandwidth and transmission distance, while others are for considering mobility and economy. Local optimality does not mean global optimality. Therefore, users should choose the standard that suits them according to their actual needs.