Optical technology for wireless communication systems

The late 1990s, began a large-scale expansion of the global communications network, first wide area network continues to expand, followed by a large number of metro construction. At the same time, rapid growth of users within the LAN. These high-speed LAN connectivity to operators of communications networks, we must rely on large-capacity access networks.
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         Although fiber-optic transmission rate can solve the problem, but the laying of the expensive and time-consuming, but limited its development. Many wireless communication technology can solve the "last mile" problem, but there are applications for the frequency channel congestion, and difficulty and safety of electromagnetic radiation, how to provide fast, low-cost, secure broadband access has become an urgent problem to be solved.

         Light transmission is a newly developed wireless broadband access methods, optical communications and wireless communications with products, optical laser devices with wireless communication technology development and utilization of engineering and matures. It uses highly concentrated beam of light through atmospheric space as a carrier of information transmission, rather than by optical fiber to transmit signals.

         This technology in the composition of the access system optical fiber transmission system with very similar physical form is very simple, users do not need to apply radio frequency, and initial low investment, low operating costs, fast installation, can provide fiber-optic system similar to the transmission bandwidth.

         As the system has a fast transfer rates, simple structure, flexible networking, etc., in cross-river crossing, which do not have cable access conditions and the need to quickly set up communications networks where there is high value, but also by more and more telecommunications operator's attention, expanding range of applications. Such systems have been commercially available in capacities ranging from 100Mbit / s to 2.5Gbit / s.


         There are also some experiments using WDM technology, to 160Gbit / s rate. Despite the weather conditions, can only be used within a short distance, generally limited to 2km below. However, in many cases, as a unique way, optical wireless access can play a good role, as the current broadband access has several very good complement.