Research And Implementation Of Channel Estimation For Wireless Communication System

Mobile communication technology has been developed rapidly and applied extensively in recent years. The time-varying characteristic of channels is one of the main obstacles to improve the capacity and reliability of wireless communication systems. The wireless communication channel is usually time-varying because radio wave propagation is difficult to control. Therefore, accurate channel estimation and equalization are very crucial for an effective communication system. At the same time, researches of communication systems are more and more converted into analysis of non-ideal channel state information from the ideal conditions of theoretical analysis where impact of channel estimation and equalization has been a major factor which can not be ignored. With the development of mobile communication networks, future mobile communication systems have more and more demands for high spectrum efficiency and transmission rate. Along with these high spectrum efficiency and high-speed mobile communication technologies, we have higher requirements on the performance and complexity of channel estimation.OvCDM is a code division multiplexing technology with high frequency efficiency which was first proposed by Li Daoben in Beijing University of Posts and Telecommunications. It combines coding, multiplexing and multi-address well in order to improve the coding gain as well as to acquire high communication capacity and spectral effieciency using parallel convolutional code. MIMO technology adopts multi-array technology and can significantly improve channel capacity and will become the key technology of the next generation mobile communications. MIMO non-realtime testbed can conqure the problem which exists when we use simplified wireless channel to do the wireless communication algorithm validation. This testbed pass through an entire transmission process and the real wireless transmission channel. The signals which are resumed can test the performance of MIMO system more accurately which make the testbed have great significance.The main work of the thesis:1. After analyzing the ordinary channel methods, we fully make use of the iterative receiving structure of the OvCDM system and adopt the joint iterative channel estimation and decoding algorithms to improve the system performance and lower the complexity of channel estimation.2. We estimate the SNR and then moderate the channel estimation parameters according to the estimated channel state information so that we can get higher frequency efficiency and channel capacity with a given power.