The New Generation Of Wireless Communication Systems Stbc Technology Research

The demand for wireless communication services is growing at an explosive rate. Next generation (B3G/4G) wireless communication systems need to access to a very large amount of data stream including enormous high speed text, voice and multimedia messages. To support these services, channels with large capacities are necessarily required. But the problems of multipath and multiple access interference restrict the steps of development. The Multiple Input Multiple Output (MIMO) system technology gives our light to solve the problems. It turns multipath from unfavorable factors to advantageous ones, and thus increases the channel capacity efficiently. As the one of the kernel parts of MIMO architecture, Space-Time Block Codes (STBC) technique is a new scheme with much potential power. It uses the transmit diversity technique in MIMO channel to provide a high quality, reliable, fast, low cost way of wireless communication.The major points of this thesis are to research the STBC technique. The main works are as follows:Describe the structure characters and principles of MIMO system. Discuss the capacity problems of MIMO channel. Give an insight of the relationship of factors restricting MIMO channel capacity and the function by simulation experiments.Describe the current research situation of STBC. Introduce the main STBC methods in detail and analyze the performances comprehensively. By comparison, indicate that STBC technique has not been mature. The outstanding features and the situation of lack of theory system supports determine the technique has much powerful potential and research space. It is discovered that diversity order, transmission rate and time slot block number are the main contradictions in STBC design (on the condition of the transmit antenna number n > 2, complex signal constellation). Trade-off idea should keep in mind. So it is a more wise choice to increase the transmission rate and optimize the time slot block number on the condition of keeping the full diversity order in STBC design. In a sense, the capacity of MIMO channel increases in accordance with antenna number in system. More over, a complex signal constellation can provide higher spectrum efficiency than a real signal constellation. Based on these ideas, this thesis present a new STBC system design which based on (6×4) or (8×4) antenna structures with complex signal constellations. The numerical calculations are also provided in detail. Keeping full diversity order gain, the design can achieve 0.5 transmission rate. A new constellation mapping design is also presented which is adapted to 3GPP specification. The design can let STBC subsystem become more flexible in concatenate processing. The feasibility and performance of the new STBC system design are fully verified by simulation experiments. Not only the transmission quality is increased much, but fast system processing can be achieved. So the new design is much valuable in practice.