Design Of TD-SCDMA Repeater

TD-SCDMA network of China's third generation mobile communication is trying to be operated in some large cities, and is being implemented commercially; TD-SCDMA repeater is an important part of the network. Because the needs of networking and TD-SCDMA network's optimization, and the use of repeater is flexible; the cost of repeater coverage is relatively inexpensive, a lot of repeaters will be used. So, the study and design are very important.Because of China's TD-SCDMA system being a new mobile communication system , the study of TD-SCDMA repeater has just begun in these years, the technology realization and engineering applications are at an early age, and hence not mature. TD-SCDMA system is a TDD system, in which the frame synchronization technology is one one of the key technologies. This paper has developed two reliable methods for frame synchronization, Power-detected-synchronization and GPS- synchronization. TD-SCDMA repeater works in 2010～2025MHz band range, the Gain-control of which requires large and flexible regulation extent .This article proposes a fast Automatic-gain-control method, and the controlled loop is composed by PIN-Diode-Attenuator and Microstrip-directional- coupler.Based on the above develops two controlled program, this paper proposes two methods for synchronization, by means of simulation tools of Pspice and ADS softeware, and development modules of DSP and C8051F340. One is controlled by C8051F340, which adopts GPS-synchronization skill; the other is controlled by DSP, which uses Power-detected-synchronization technology. At the last parts of this paper, some key moudles of TD-SCDMA repeater are designed, including LNA, PA, AGC-LOOP, and microstrip filter.It can be seen from the simulation results that the two programs with its design are superior and easy to be implemented. This article provides a reliable design method for developping TD-SCDMA repeater, and also provides design theories for 4G.Repeater. It is very useful for TD-SCDMA repeater's production, which could reduce the development period and cost.