Joint Channel and Phase Noise Estimation in OFDM Systems
Ahmed Deiaa Mohamed Talaat Ahmed;
Abstract
Orthogonal Frequency Division Multiplexing (OFDM) systems are highly used in mod- ern standards such as LTE, WiMax and DVB because of their practical and simple hardware implementation as well as their robustness against frequency selective chan- nels and inter-symbol interference(ISI).
However, OFDM systems are very sensitive to phase noise and doubly-selective channels that cause inter-carrier interference (ICI) to the received signal. The resulting ICI can cause severe performance degradation for OFDM systems.
This thesis is concerned with the mitigation of both doubly selective channels and phase noise effects in OFDM systems. The effects of both doubly selective channels and phase noise in OFDM systems are studied and an algorithm is proposed to mitigate both effects by applying an iterative decision-directed feedback method where the most significant ICI components are estimated. Moreover, the error propagation that occurs from one iteration to the next is reduced by using the estimated doubly selective channels and by reducing the residual phase noise.
The thesis starts with an overview on the OFDM technique where an introduction to its main idea is provided as well as its main advantages and disadvantages.
Then, a detailed study is provided for the effects of both phase noise and doubly selective channels as well as a literature review for the recent proposed algorithms for mitigating them.
Finally, an algorithm is proposed to mitigate these effects and simulation results are presented to show the performance versus the perfect decision directed feedback case for different system and design parameters. The simulation results have shown that the proposed algorithm achieves a significant performance close to the perfect decision directed feedback case for different practical standards channel models as well as different modulation orders.
Key words: Doubly selective channels, Inter-Carrier Interference (ICI), Orthogonal Frequency Division Multiplexing (OFDM), phase noise, iterative decision-directed feedback.
However, OFDM systems are very sensitive to phase noise and doubly-selective channels that cause inter-carrier interference (ICI) to the received signal. The resulting ICI can cause severe performance degradation for OFDM systems.
This thesis is concerned with the mitigation of both doubly selective channels and phase noise effects in OFDM systems. The effects of both doubly selective channels and phase noise in OFDM systems are studied and an algorithm is proposed to mitigate both effects by applying an iterative decision-directed feedback method where the most significant ICI components are estimated. Moreover, the error propagation that occurs from one iteration to the next is reduced by using the estimated doubly selective channels and by reducing the residual phase noise.
The thesis starts with an overview on the OFDM technique where an introduction to its main idea is provided as well as its main advantages and disadvantages.
Then, a detailed study is provided for the effects of both phase noise and doubly selective channels as well as a literature review for the recent proposed algorithms for mitigating them.
Finally, an algorithm is proposed to mitigate these effects and simulation results are presented to show the performance versus the perfect decision directed feedback case for different system and design parameters. The simulation results have shown that the proposed algorithm achieves a significant performance close to the perfect decision directed feedback case for different practical standards channel models as well as different modulation orders.
Key words: Doubly selective channels, Inter-Carrier Interference (ICI), Orthogonal Frequency Division Multiplexing (OFDM), phase noise, iterative decision-directed feedback.
Other data
| Title | Joint Channel and Phase Noise Estimation in OFDM Systems | Other Titles | التقدير المشترك للقناة وضوضاء الطور في أنظمة الخلط بالتقسيم الترددي المتعامد | Authors | Ahmed Deiaa Mohamed Talaat Ahmed | Issue Date | 2017 |
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