| The indoor communication distribution system went through in-depth coverage inthese years, but some disadvantages also began to appear with the widely utilization ofcoaxial distribution system, such as the incapability of wide range coverage caused bythe massive loss during transmission; the high relay equipment noise leads the outdoorresources consumed by the indoor call, the load and the flash pressure on outdoor macrocell can’t be shared effectively; the problems caused by the frequent splitter andcombiner due to the increased WLAN utilization in present system. Herewith the UltraWide Band gradually comes into our vision with its unique superiority.UWB system using wavelength division multiplexing technology, can supportmulti-standard network systems transmitted in the same fiber optic cable, is the simplestindoor distribution technology with commercialization prospect. UWB system consistsof digital POI, digital remote unit and light cover unit, divided as information source,trunk, and antenna feeder. Information source is provided by ISP, support multi-standardinput; Trunk is set up by digital POI (i.e. multi-system combination platform, POINT OFINTERFACE) and digital remote unit connecting by a number of optical fiber or cable,can be constructed in various types of network, such as star type, chain type, tree type orring type. Among them, ring type is the optimal network structure because it supports thesecondary backup. Any equipment breakdown will not affect the others, which greatlywill decrease the risk of data storage. Antenna feeder setting up the same as ordinarydistribution can expand its coverage area via the flat layer distribution. For outdoors orthe sites with a plain interior structure, such as residential area, stadium, airport,exhibition center etc., the optical fiber antenna system can be used directly.This thesis elaborated the superiority of UWB system through the study on UWBfeatures and its network structure, and details as listed below.Firstly, the call quality;After the practical applications and tests of UWB in the indoor distribution system,confirming that UWB system can optimize and improve the call quality in the indoor distribution system.Secondly, bandwidth;UWB system can centralize different standard sources on POI, and then via OSUand ORU transmitting to the terminal. Comparing with the traditional End Joint Road incoaxial distribution system, UWB can save not only the usage of combiner and otherdevices, but also the cable resources.Thirdly, network structure;The traditional distribution system normally consists of front and rear section withstar type or chain type of network structure. In this way, one front section can only workwith4rear sections at most, and the more rear sections, the more light attenuations,which will have more influence on the devices when receiving the source signal.Whereas, UWB system can construct a ring type of network, which will not only realizethe double POI backup, but also series connect30sets of OSU at most, with theminimum effects on the rear light attenuation.Fourthly, investment;Traditional distribution system needs to combine more3G or DSC devices in orderto achieve better field strength coverage. As more devices will have to be implementedin this way, more cable resources will also needed. Obviously this will bring even morecost. Though UWB system is not very competitive in single system, it will decrease theinvestment greatly in multi-standard system as many source equipments, optical cablesand devices will not be necessary.Based on the road test results from the experimental subject, this thesis proves thatUWB systems on the present network optimization is better than the traditional coaxialdistribution, makes up the deficiencies in the traditional distribution system to someextent, and will be of great importance to improve the present network quality. |
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