Comprehensive comparison of various Wireless Access Technologies

Wireless access technology is worthy of our research. Many people may not understand wireless access technology and its features. It does not matter. After reading this article, you must have gained a lot, I hope this article will teach you more things. Now, all operators have their own backbone networks, but the planning and construction of their access networks play an important role in connecting customers to their own networks as quickly as possible. Currently, due to factors such as urban construction, the construction speed of Optical Cables cannot meet the requirements of users who need fast wireless access technology. To solve this conflict, more applications of wireless transmission and wireless access technology systems have become necessary measures adopted by operators. Wireless systems are divided by operating frequency and can be divided into high-frequency and low-frequency segments. They can be divided into PDH, SDH, LMDS, MMDS, spread-spectrum, infrared and satellite communication systems by standard, to facilitate the rational application of wireless systems in the network, we will introduce the features, networking methods, and system capacity of the currently widely used wireless systems. LMDS provides a low-cost and effective solution for densely populated urban communications, using a high-capacity wireless local environment, it can quickly provide data and voice services for a large number of user areas, and is suitable for fast wireless access technology for small and medium-sized enterprises, small offices, and home offices in commercial buildings.

Main features:
◆ 10 GHz ~ Broadband Wireless Access Technology at 40 GHz, with high bandwidth and speed;
◆ Point-to-point, one base station serves multiple user units, and multiple users share bandwidth;
◆ Use ATM/TDMA and other technologies on wireless channels to dynamically allocate bandwidth and ensure end-to-end QoS;
◆ Multiple types of business data, voice, and video can be provided ). MMDS systems are widely used at GHz point-to-point multi-point systems. The RF bandwidth of this system is 30 MHz and is suitable for users with 1 E1 + 10 BASE-T. Due to the long transmission distance, it is suitable for large-scale coverage and can quickly provide services for users.

Main features:
◆ The shared bandwidth system can implement point-to-point multi-point allocation;
◆ Point-to-point structure of the dedicated bandwidth system;
◆ Small-sector/omnidirectional-sector deployment business capacity expansion flexibly covers thousands of users );
◆ Interfaces of outdoor units (ODU), antennas, and feeder are open for cooperative manufacturing.
◆ Business applications include TDM, leased line services, and IP services. SDH microwave technology is relatively mature, mainly used for 155M or above the trunk line transmission and major account access, interface STM-1/OC3 optical port and electrical port. It is mainly used for point-to-point communication.

Main features:
◆ Transparent circuit transmission, support for various business data, voice, IP, frame relay, ATM, etc.) and layer-based clock signal transmission;
◆ The network structure can be a ring, star, or chain network;
◆ SDH ring network self-healing function.
◆ System applications include connection between point-to-point wireless access technology of high-business customers and backbone nodes of man.

PDH microwave is a mature point-to-point communication system technology with reasonable cost. interfaces include E1, 4E1, 8 E1, 16E1, and 2x16E1 series. Applicable to users of TDM leased line wireless access technology.
Applicable users of spread spectrum microwave include Ethernet interface and E1 interface. Applicable to point-to-point wireless communication for all line-of-sight transmission.
Main features:
◆ Strong anti-interference ability;
◆ You only need to apply for an ICP filing from the management department. Far Infrared Communication System infrared communication working wavelength is 860nm ~ 920nm, 10Base-T and 100Base-T Ethernet interfaces, 155 M OC3 interfaces, fog and dust have a great impact on transmission, and the theoretical coverage distance is 2 ~ Within 3 kilometers, generally used for several hundred meters. Applications are used for temporary access.

Main features:
◆ Monochrome: The frequency is up to 3x1014Hz;
◆ Directionality: transmission within a small three-dimensional angle, good confidentiality; on the contrary, large electromagnetic emission angles and poor confidentiality;
◆ None: it is a "green" communication. DVB satellite communication is an indispensable means of auxiliary transmission for the establishment of international and cross-city long-distance transmission networks. For users far away from man, satellite is an ideal access method. Netcom has now activated the Ku-band DVB standard master station and connected users in Beijing and other places. The downlink behavior of the system is 2 M, 4 M, 8 M, and kb.

Main features:
◆ Simple application;
◆ The system cost is independent of the transmission distance and geographical environment conditions. Wireless Optical Fiber is suitable for connections between large-capacity customer point-to-point access and man backbone nodes.

Main features:
◆ The SDH ring network self-healing function can be used together;
◆ Flexible network creation methods;
◆ You can purchase an ADM device to provide different interfaces.

The wireless access technology has the features of large capacity, comprehensive service bearer access, and Fast deployment. Compared with other wireless access technologies, it is regarded as the latest flexible Replacement Technology for fiber optics-known as "wireless fiber optics ". Wireless access technology is also an important solution to adapt to the current fast broadband access by emerging telecom operators. It is a rapid deployment of Metro access networks by emerging telecom operators such as China Netcom, this is an effective means for users to access the last mile.

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