| Channel Modeling and Estimation For Wireless Sensor Array Networks
Advances in technology make it possible to design multi-functional sensor elements with small size and low power consumption. These elements, which are able to make sensing, data processing and communicating with each other, constitute Wireless Sensor Array Networks.
The wireless communication channel in a sensor network is exposed to corruptive effects like additive noise and jammer interferences. Also, the signal at the receiver is delayed and attenuated due to multipath fading. In addition, Doppler frequency shifts occur due to mobility. All these impediments change randomly over time. Therefore, modeling and estimation of this time varying communication channel has become an important issue in the design of the receivers that improve the performance of communication systems.
In this study, we investigated how to model and estimate the time varying channel of wireless sensor networks with multi-carrier spread spectrum (MC-SS). Time-frequency representation has been proposed as a unique approach to the solution of the problem. Wireless communication channel was modeled in terms of attenuation factor, Doppler frequency shifts and delay parameters. The channel parameters have been estimated via a spreading function using the discrete evolutionary transform (DET) as a time-frequency analysis method, and used to equalize the channel. In order to illustrate the performance of the proposed method, simulations with different levels of channel noise, jammer interference and Doppler frequency shifts are provided. The results we obtained show that the proposed time varying channel model improves the receiver performance.
PINARBAŞI Murat
Danışman :Prof. Dr. Sıddık YARMAN
Anabilim Dalı :Elektrik-Elektronik Mühendisliği Anabilim Dalı
Mezuniyet Yılı :2009
Tez Savunma Jürisi :Prof. Dr. Sıddık YARMAN
Prof.Dr. Aydın AKAN
Prof. Dr. Hakan Ali ÇIRPAN
Prof. Dr. Osman Nuri UÇAN
Prof. Dr. Filiz Güneş
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