Indoor Radio Network Optimization

While a significant amount of traffic will migrate from mobile to fixed networks, a much greater amount of traffic will migrate from fixed to mobile networks. In many countries mobile operators are offering mobile broadband services at prices and speeds comparable to fixed broadband. Though there are often data caps on mobile broadband services that are lower than those of fixed broadband, some consumers are opting to forgo their fixed lines in favor of mobile. There is a growing interest in providing and improving radio coverage for mobile phones, short range radios and WLANs inside buildings. The need of such coverage appears mainly in office buildings, shopping malls, train stations where the subscriber density is very high. The cost of cellular systems and also the one of indoor wireless systems depend highly on the number of base stations required to achieve the desired coverage for a given level of field strength. (Murch 1996) The other promising technique is the Hybrid Fiber Radio (HFR)-WLAN which is combines the distribution and radio network. The advantages of using analogue optical networks for delivering radio signals from a central location to many remote antenna sites have long been researched and by using the high bandwidth, low loss characteristics of optical fiber, all high frequency and signal processing can be performed centrally and transported over the optical network directly at the carrier frequency. The remote site simplicity makes possible the network cheap and simple, requiring only optoelectronic conversion (laser diodes and photo-detectors), filtering and amplification. Such Remote Units (RU) would also be cheap, small, lightweight, and easy to install with low power consumption. The design objectives can list in the priority order as RF performance, cost, specific customer requests, ease of installation and ease of maintenance. The first two of them are close related to the optimization procedure introduced and can take into account at the design phase of the radio network.