Design And Realization Of WCDMA Base Station Downlink Receiving And Testing System

At present, most of WCDMA base station produces are based on modular design. The base band module is one of the most complicated module which is responsible for generate the base station downlink base band signals. How to verify the correctness of base band modular processes has become a key issue. The goal of this paper is design a WCDMA base station downlink receiving and testing system to receive and measure the downlink signals generated by the base station base band module, so as to achieve the purpose of inspection base band module.Through a carefully study of 3GPP-Release8 version protocol, this paper proposed an overall design plan of WCDMA base station downlink receiving and testing system, and realized the whole system in the MATLAB platform. Receiving and testing system supports all of physical channel which Release8 version protocol provided, and supports a variety of business rates and the number of users. It consists of two modules: receiving module and the EVM measurement module. The main task of receiving module is to complete the reception of the downlink base band signals, including matched filtering, descrambling, despread, demodulating, deinterleaving, rate de-matching, channel decoder, CRC removement and so on. The function of EVM measurement module is measuring EVM value of the downlink signal which reflects modulation quality.In order to ensure the correctness of receiving and testing system, this paper designed a large number of test cases. The receiving module was tested with completeness and consistency, and simulated the receiver performance. In addition, the EVM measurements of receiving system were compared with EVM measurements of commercial test instrument. The results show that receiving and testing system can receive and measure base station downlink signals with completeness and consistency, and EVM measurements are accurate.