B3G Some Of The Key Technologies Of The System And Performance Evaluation

With rapid development of wireless communication, the requirement of real time video, broadband data, voice communication and accurate orientation also expands. So it is a trend to develop a broadband wireless access system that can guarantee high data rate and high spectrum efficiency.Since last century, a new wireless communication system named B3G/4G system has been studied worldwide, accompany with many new technologies such as OFDM, MIMO, HARQ and so on.In this paper we focus on several key technologies of B3G system, for example, OFDM, MIMO, HARQ, etc. First of all, we introduce the principle of OFDM, the reference signal design of OFDM system and the 2D-wienner channel estimation algorithm based on reference signal. Then, the principle of HARQ is introduced, and two HARQ strategies named Chase Combining and Incremental Redundancy are compared. In the following, several precoding strategies of LTE systems are evaluated and compared. The performance of the two popular channel coding schemes named Turbo and LDPC are compared in the LTE system. Finally, we optimize the channel quality indication signaling of the WiMAX system, so that the net throughput can be maximized.