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Title: Synchronization and data detection in wireless sensor networks
Author: Ying, Yeqiu
ISNI:       0000 0001 3575 2905
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2007
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Wireless'sensor networks (WSNs) have been envisioned as one of the most 'important emerging technologies that can greatly impact the world. With the recent advancement in both electronics and wireless communication networks, implementing WSNs in practical applications has become feasible and can be the near future. However, current communications protocols are not suitable for use in WSNs due to the unique characteristics and the system constraints such as low power consumption, and low computational and hardware complexity. '\. In this thesis, we focus on the physical (PRY) layer design issues including . transmission medium selection, and transceiver design. Specifically, we first study a WSN architecture with a centralized topology. Motivated by the factor that if not properly treated, carrier frequency offset (CFO) and multipath channel can cause great degradation of data detection performance in conventional carrier-based radio systems (narrow-band and wide-band systems), we address CFO and channel estimation for multiple slave sensor nodes. Relying on a unique TDMA-like training head pattern, the joint multi-user CFO and channel estimation problem can be easily decoupled. Furthermore, the joint CFO and channel estimation for each slave sensor can also be treated separately without significant performance degradation. Different CFO and channel estimators are derived and compared. Optimal training design, specifically the pilot symbols placement, for burst transmission systems is also investigated, and an equal-preamble-postamble (EPP) placement scheme is shown to be optimal. In the second half of the thesis, the emerging ultra-wideband (UWB) radio technology is investigated in the context of WSNs. We believe that this new radio technology is a strong candidate for WSN applications d?e to its unique advantages. The modulation ~d receiver schemes are stqdied and block-coded modulation and a novel noncoherent receiver are proposed for impulse radio (IR) UWB systems. The critical challenge of timing synchronization for IR-UWB signals is also studied, and a new code-assisted synchronization scheme is proposed. This semi-analog based synchronization scheme enables the usage of both coherent and noncoherent receivers, and can be executed under either blind or data-aided mode. In conclusion, this research work is expected to favorably impact the theory, design and implementation of communication transceivers for practical W8Ns.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available