Based On The Part Of The Algorithm And Module Realization Of Ieee802.16d For Mimo-ofdm Transmission System

The fast development of wireless communication technology brings about great facility to people around the world. For it's convenient to communicate with others anytime, anywhere, by any means. Meanwhile, it raises even larger demand on capacity and quality of communication systems. Then MIMO-OFDM technology comes with hope on increasing capacity and spectrum efficiency. OFDM has a fine channel granularity, and robustness to frequency-selective fading, which is quite competitive to optimize the spectrum efficiency tight to the Nyquist rate[7], by changing its modulation scheme adaptively. Moreover, if combined with MIMO, diversity or spatial multiplexing can be achieved. With transmit or receive diversity, duplicate fadings of transmitted signals are created between multiple antennas, thus mitigating error rate by Maximum Ratio Combing. Alternatively, different signals are sent to parallel spatial channels formed by multiple antennas to explore system capacity, without additional bandwidth[13]. To sum up, MIMO-OFDM is really promising in beyond 3G technique family.This paper focuses on architecture and application of MIMO-OFDM in broadband wireless communication systems, and the rest of it is organized as follows:First, it presents an IEEE 802.16d WirelessMAN system. After that, SUI channel modeling and corresponding parameters are discussed in detail.Then ideal and actual spectrum efficiency of MIMO-OFDM system is analyzed. It shows that the spectrum efficiency is related to correlation factor of antennas and power allocation schemes. The correlation factor is a key reference of coordinating between diversity and spatial multiplex. As an example, spectrum efficiency of ZF-VBLAST system with simplified transmit power allocation schemes is analyzed and simulated, which is comparable with optimal scheme.Next referring to a MIMO-OFDM system, the design criteria of preambles are derived. After that different patterns of preambles are discussed and simulated. Then, detect and channel estimation of an Alamouti-OFDM sytem and a BLAST-OFDM system are simulated and analyzed in both system performance and feasibility.Finally this thesis gives a simplified Alamouti-OFDM coding architect for implementation, by cutting down an IFFT module, which is really resource consuming in the whole system.