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Title: Simulation of space-time processing techniques for wireless communications
Authors: Goh, Keng Wee
Keywords: DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
Issue Date: 2003
Abstract: Space-Time and "Turbo" processing are two of the most explored concepts in recent wireless communication research. Theoretically, "space-time" processing is a method to increase the possible capacity by exploiting the rich multi-path nature of fading wireless environments while "turbo" coding is a technique to approach the Shannon capacity limit. The combination of these two concepts provides a practical way to increase the channel capacity over a wireless channel. Our objective is to construct simulation models for characterizing the performance of space-time and turbo processing systems. Firstly, the concept of space-time block codes (STBC) and generalized orthogonal designs was reviewed. Simulations results show the theoretical ML decoding error bounds, effects of transmit/receive diversity and channel estimation errors. Secondly, we review Turbo codes and iterative decoding with a simple early stopping criterion. Simulations results show the performance of iterative decoding using Log-MAP algorithm with iteration control. Thirdly, a serial concatenation of outer turbo codes and inner STBC combines the merits of both coding techniques, achieving improved performance with transmit/receive diversity and iterative decoding. Lastly, the system capacity was increased with multi-user interference cancellation (IC) techniques that exploit the orthogonal structure of STBC. For a case of two cochannel users, zero forcing (ZF) and minimum mean squared error (MMSE) IC schemes are compared. The MMSE IC scheme is generalized for K cochannel users. This improves the overall capacity and reduces the number of receive antennas to K, as compared to classical IC techniques. The concatenated Turbo-STBC coding concept was applied to the generalized MMSE IC scheme and simulations shows linear improvement in capacity with increased cochannel users. This result was previously not achievable with STBC. The resultant hybrid coding framework has immense potential to increase data rates and capacity of the physical layer interface in next generation wireless communication systems.
Description: 119 p.
Rights: Nanyang Technological University
Fulltext Permission: restricted
Fulltext Availability: With Fulltext
Appears in Collections:EEE Theses

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