The Research On Main Algorithms Of Sniffer For TD-SCDMA Home Nodeb

Femtocell is a mobile communication system indoor coverage solution. There is more research on WCDMA femtocell. TD-SCDMA system is Chinese own R & D system with a late start, so there are still many problems about TD-SCDMA Femtocell. Some femtocell devices already have been done, but there are still some technical problems. These issues include networking, synchronization, interference, switch, etc. If these problems are not completely resolved, Femtocell would not be in large-scale application.Femtocell booting has two stages. The first stage is searching the surrounding base stations. The second stage is the Femtocell configures itself, according to search out the information around, in order to achieve minimal interference between systems. After self-configuration, Femtocell began to serve as base station. The difference is that the transmit power of Femtocell relatively is smaller; users supported by femtocell are relatively smaller.In the base station sniffer phase, Femtocell should search configuration information of all existing macro base station. This stage is very important, because aware of configuration information of macro base station, femtocell could configure itself with minimizing interference between base stations. So sniffer is to ensure that Femtocell could work properly.In this paper, sniffer process has been analyzed and main algorithm during the sniffer phase has been researched. In the search module of pilot channel, search algorithm has been improved, and the simulation shows that the improved search algorithm can work at a lower signal to noise ratio. After frame format of TD-SCDMA system has been analyzed, algorithm for frequency offset estimation with code and midamble codes syncdl has been researched.The simulation shows that with the algorithm frequency offset can be controlled within 200Hz offset. Using the method of search the first path to make Femtocell synchronize with macro stations, and the simulation shows that time offset can be controlled within 3 microseconds.