Quantum Signal Processing And Quantum Information In Multi-user Detection

Quantum signal processing (QSP) is aimed at developing new or modifying existing signal processing algorithms by borrowing from the principles of quantum mechanics and some of its interesting axioms and constraints. However, in contrast to such fields as quantum computing and quantum information theory, it does not inherently depend on the physics associated with quantum mechanics. This framework provides a unifying conceptual structure for a variety of traditional processing techniques and a precise mathematical setting for developing generalizations and extensions of algorithms, leading to a potentially useful paradigm for signal processing with applications in areas including frame theory, quantization and sampling methods, detection, parameter estimation, covariance shaping, andmultiuser wireless communication systems.Quantum information theory is a novel theory mode, which is based on the principles of the quantum mechanics and performs computation, coding and information transmission by a variety of coherent characteristics, for instance, quantum parallel and quantum tangle, of the quantum systems. Because of the different special properties of the quantum system to the classic system, it can afford us more powerful, secure computational abilities and information processing abilities.Multi-Access Interference (MAI),multi-path fading and near-far effect are the predominant factors that determine the performance of receivers in Code Division Multiple Access(CDMA) system, but MAI is not inevitable. Multiuser detection (MUD) can reduce MAI effectively, relax near-far effect dramatically, improve the system performance obviously and increase the system capacity. MUD, which can effectively suppress multiple access interference (MAI) and inter-symbol interference (ISI), and alleviate "near-far" effect problem inherent in CDMA systems, has been regarded as a key technique in the third-generation (3G) and future 4G mobile systems. This advanced signal processing technique has the potential to enable high capacities suited for Internet and multimedia services, and also dramatically increase range and reliability. Aiming at computation complexity simplification, robustness, blind adaptive implementation, and parallel implementation, this dissertation is focused on multiuser detection based on quantum signal processing and quantum theory. The main contributions and original ideas included in this dissertation are summarized as follows.1. A blind orthogonal multiuser detector has been proposed with quantum signal processing and subspace method. It can mitigate both the effect of the MAI and the noise component.2. A quantum multiuser detector based on improved Grover search algorithm is proposed. Because the algorithm can improve the searching successful rate, the multiuser may improve the performance.3. A quantum LMS algorithm based on quantum gradient and quantum Fourier transform. It is more quick and accurate; for the faster speed of the quantum calculation. So we can use this algorithm in Multiuser detector to resolve the high calculate complexity.