Co-channel Interference Suppression for Ofdm Systems
Co-channel Interference Suppression for Ofdm Systems

Author: Jonghyun Won

Publisher:

Published: 2003

Total Pages:

ISBN-13:

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ABSTRACT: We propose new methods for co-channel interference suppression in orthogonal frequency division multiplexing (OFDM) systems with multiple receive antennas. Our methods use a low-order time-domain model to parameterize the matrix-valued spectral density of the noise and interference. A penalized maximum likelihood-function approach is used to choose the proper model order automatically in each received data frame. We show that these methods significantly improve the symbol-error-rate when interference exists in the received data. Numerical examples are provided to illustrate the performance of our new methods and compare with conventional methods. We also discuss the diplus or minusculties associated with the application of our method to space-time OFDM (ST-OFDM).

Advanced Interference Suppression Schemes for OFDM Systems
Advanced Interference Suppression Schemes for OFDM Systems

Author: K.M. Zahidul Islam

Publisher:

Published: 2011

Total Pages: 230

ISBN-13:

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We also investigate computationally efficient reliable OFDM downlink signal detection algorithm in presence of relatively strong co-channel interference (CCI) from adjacent interfering base transceiver station (BTS). We propose and compare the performance of several per-subcarrier based CCI cancellation algorithms considering 1 and 2 receive antennas at the user terminal.

Avoiding Effects of OFDM Adjacent Channel Interference by Using Combinations of Modulation Schemes
Avoiding Effects of OFDM Adjacent Channel Interference by Using Combinations of Modulation Schemes

Author: Le Tien Anh

Publisher: GRIN Verlag

Published: 2009-05

Total Pages: 89

ISBN-13: 3640320255

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Master's Thesis from the year 2008 in the subject Engineering - Communication Technology, grade: erfolgreich bestanden, Keio University (Graduate school of Science and Technology - School of Science for Open and Environmental Systems), language: English, abstract: Non-orthogonality among adjacent OFDM channels creates OFDM adjacent channel interference and it heavily affects the entire system's performance. Conventional methods to avoid OFDM adjacent channel interference are not only insufficient but also are wasting a lot of frequency resources. In this research, a method using combinations of modulation schemes is proposed to avoid effects of OFDM adjacent channel interference. It can be obtained by modulating the sub-carriers at the outer sides of an OFDM channel with lower order modulation schemes (such as BPSK or QPSK), while modulating the sub-carriers at the inner side of the OFDM channel with higher order modulation schemes (such as 16QAM or 64QAM). Intensive simulations have been carried out to evaluate the performance of the proposed method. The simulation results have shown an increase in the OFDM system's resistance against adjacent channel interference while still maintain the bandwidth efficiency.

Frequency Sub-carrier Based Adaptive Technique for OFDM Systems with Antenna Arrays [microform]
Frequency Sub-carrier Based Adaptive Technique for OFDM Systems with Antenna Arrays [microform]

Author: Stipe Moric

Publisher: Library and Archives Canada = Bibliothèque et Archives Canada

Published: 2004

Total Pages: 154

ISBN-13: 9780612953512

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Orthogonal frequency division multiplexing (OFDM) is gaining considerable attention and is a viable candidate in future broadband wireless communication systems. However as more devices become wireless in a limited frequency environment, high powered co-channel interference suppression techniques become increasingly important. In this regard adaptive arrays have been incorporated into OFDM schemes to further increase capacity and-robustness of the overall system. We introduce here a new method to extend spatial processing techniques to mitigate high powered co-channel interference in an orthogonal frequency division multiplexing system. The proposed algorithm uses optimal weights determined from classical methods, and known frequency information, to formulate adaptive weights specific to each sub-carrier. Performance improvements are investigated through computer simulations. These simulations in near-far scenarios illustrates the importance of such a technique.

OFDM and MC-CDMA
OFDM and MC-CDMA

Author: Lajos Hanzo

Publisher: John Wiley & Sons

Published: 2007-01-11

Total Pages: 430

ISBN-13: 0470031379

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Wireless communications has witnessed a tremendous growth during the past decade and further spectacular enabling technology advances are expected in an effort to render ubiquitous wireless connectivity a reality. Currently, a technical in-depth book on this subject is unavailable, which has a similar detailed exposure of OFDM, MIMO-OFDM and MC-CDMA. A further attraction of the joint treatment of these topics is that it allows the reader to view their design trade-offs in a comparative context. Divided into three main parts: Part I provides a detailed exposure of OFDM designed for employment in various applications Part II is another design alternative applicable in the context of OFDM systems where the channel quality fluctuations observed are averaged out with the aid of frequency-domain spreading codes, which leads to the concept of MC-CDMA Part III discusses how to employ multiple antennas at the base station for the sake of supporting multiple users in the uplink By providing an all-encompassing self-contained treatment this volume will appeal to a wide readership, as it is both an easy-reading textbook and a high-level research monograph.