Perfect Space-Time Block Code And Its Application In Cooperative Communications

With the rapid development of communication techniques, the demand for wide-band data rate and improved communication quality is growing as well. Since the available radio spectrum resources are very limited, multiple input and multiple output technique offers a spectral efficient transmission scheme by accommodating more data streams within the same radio spectrum. While space-time coding is the fundamental signal processing technique to realize the benefit of MIMO system. Efficient encoding and decoding methods could be utilized to improve the radio communication performance significantly, space-time coding has seen its fast development and found widely application in practical communication system within a decade.After a brief introduction of the MIMO system model, and the capacity of MIMO system is reviewed at first to explicate how and why the transmission may benefit from this key technique. Then, some of the optimized criteria for the space-time code design are addressed to highlight the practical design problem of the three categories of the space-time codes. The simulations are performed to show that, the VBLAST system is simple to be implemented and exhibits high frequency efficiency, the achieved diversity order is low; The STTC system will offer satisfactory coding and diversity gain, but the frequency efficiency can not be improved, meanwhile, its decoding complexity is comparatively high; Among three system, the orthogonal design based space-time block code is straightforward to be implemented and is able to achieve full diversity order, but the frequency efficiency is not good enough either when comparing to that by using the VBLAST system.In 2006, Oggier proposed a new kind of space time code, namely the so called perfect space-time block code (PSTBC) scheme. The PSTBC has the following six advantages, i.e., full-rate, full-diversity, nonvanishing constant minimum determimant for increasing spectral efficiency, uniform average transmitted energy per antenna and good shaping. In this paper, the construction of the perfect space-time block code will be addressed based on the cyclic division algebra basis. Then the equivalent VBLAST model based on the code matrix and MIMO transfer matrix transformation will be reviewed at first to highlight the state of the art in the existing detection algorithms for the PSTBC in the literature. Then the trellis interpretation of the VBLAST-type detection problem is proposed to enable the minimum mean-square error decision feedback equalizer Viterbi (MMSE-DFE-Viterbi) algorithm. It is validated through simulations that, for all different modulation alphabet size and modulation type, the proposed MMSE-DFE-Viterbi algorithm outperform the existing known detection algorithms for the PSTBC with a reasonable increase in the computational complexity.In order to solve the wide area wireless signal coverage requirement and to support broadband transmission capability, cooperative communication will be one of the most important forms for the future communication infrastructure, wherein the cooperation among different users will become an effective scheme to make full use of the limited available resources. How to apply the PSTBC in the cooperative communication environment is another research topic of this thesis. Recently, Oggier proposed the algebraic algebraic coded cooperation model and derived the equivilanet non-cooperative communication model. Motivated by this work, a new coded cooperation model is proposed based on the cyclic division algebra to derive the equivalent PSTBC coded cooperation scheme. And it is shown that the proposed coded cooperation analysis offers a simplified equivalent analysis method for the application of PSTBC in cooperation environment. The corresponding detection algorithm is investigated as well. Simulation results are presented to validate the effectiveness of the proposed detection algorithm. Meanwhile, this paper proposes a general space time codded cooperatoin model with amplify and forward strategy in the communication environement wherein one antenna is assumed at source, relay and destination. It is shown that the similar detection algorithm for the PSTBC could be utilized to recover the data reliably. And the achieved performance shows that the PSTBC codes could also be utilized in the cooperative communication scenarios.