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Book Adaptive Semiblind Channel Estimation for OFDM OQAM Systems

Download or read book Adaptive Semiblind Channel Estimation for OFDM OQAM Systems written by Tianze Su and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis, we propose and investigate novel adaptive semi-blind channel estimation algorithms for OFDM/OQAM systems. OFDM/OQAM is regarded as a promising alternative to conventional CP-OFDM for multi-carrier modulation since it can provide better spectrum efficiency, albeit at the price of increased complexity. We first formulate a general system model of an OFDM/OQAM transceiver. Based on this model, we review a recently proposed block based semi-blind channel estimation method for OFDM/OQAM systems, known as the sign covariance matrix (SCM) method. This method mainly exploits the higher-order statistical properties of the data at the receiver side but is not well-suited for applications to time-varying channels. Subsequently, to overcome the drawbacks of this block-based technique, we propose adaptive semi-blind channel estimation algorithms for application to OFDM/OQAM. The proposed algorithms consist of an adaptive SCM technique obtained through exponential recursive averaging, as well as several constant modulus algorithms (CMA) for recursive estimation. Although all the adaptive algorithms are designed to deal with time-varying channels, they can also be used for rapid channel acquisition in the case of static or slowly-varying channels. Furthermore, we explore the coherence bandwidth of the channel and make use of this concept to improve the estimation accuracy via a frequency averaging technique that can be combined with the adaptive SCM. Simulation results validate the efficacy of the proposed adaptive estimation algorithms over both time-invariant and varying channels, showing their robustness in terms of convergence speed, tracking capability and residual estimation error in steady-state. In particular, the CMA with recursive least squares (CMA-RLS) updating proves to be the most preferable due to its excellent trade-off between convergence rate and residual error level. The CMA-RLS also offers the best performance in tracking a time-varying channel. In addition, simulation experiments demonstrate the effectiveness of combining the frequency averaging technique with the proposed adaptive SCM algorithm." --

Book Blind Adaptive Channel Estimation in OFDM Systems

Download or read book Blind Adaptive Channel Estimation in OFDM Systems written by Xenofon G.. Doukopoulos and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book CHANNEL ESTIMATION FOR OFDM SYSTEMS

Download or read book CHANNEL ESTIMATION FOR OFDM SYSTEMS written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, various pilot symbol aided channel estimation and tracking methods are investigated and their performances are compared for an OFDM system with packet based communication on HF channel. For the HF channel, Watterson HF channel model is used. The compared methods are least squares (LS) channel estimation, linear minimum mean square error (LMMSE) channel estimation, least mean squares (LMS) channel tracking, recursive least squares (RLS) channel tracking, constant position model based Kalman filter channel tracking, and constant velocity model based Kalman filter channel tracking. For LMS and RLS methods some adaptive approaches are also investigated.

Book Semi Blind Carrier Frequency Offset Estimation and Channel Equalization

Download or read book Semi Blind Carrier Frequency Offset Estimation and Channel Equalization written by Yufei Jiang and published by Springer. This book was released on 2015-12-01 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This SpringerBrief investigates the performance of semi-blind independent component analysis (ICA) based equalization and carrier frequency offset estimation approaches (CFO) for a number of orthogonal frequency division multiplexing (OFDM) based wireless communication systems. It provides a comprehensive overview of the challenges of channel equalization and frequency synchronization for different wireless systems. The authors present the wireless communication channel and system models. Key existing CFO estimation methods are reviewed, along with a number of the training based and non-training based (blind) channel estimation methods. This is followed by a study of ICA and its applications to OFDM-based wireless communication systems. Later chapters provide a detailed description of recent research on semi-blind CFO estimation and ICA based equalization approaches for various wireless communication systems including multiple-input multiple-output (MIMO) OFDM and coordinated multipoint (CoMP) systems. Semi-blind CFO estimation and equalization structures provide a spectrum-efficient and high-performance solution for high speed wireless communications. This book is suitable for postgraduate students, researchers or professionals in the area of wireless communications.

Book Adaptive Algorithms for Wireless Channel Estimation

Download or read book Adaptive Algorithms for Wireless Channel Estimation written by Tareq Y. Al-Naffouri and published by . This book was released on 2005 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Adaptive Channel Estimation for Orthogonal Frequency Division Multiplexing Systems

Download or read book Adaptive Channel Estimation for Orthogonal Frequency Division Multiplexing Systems written by 張喻斌 and published by . This book was released on 2003 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Channel Estimation

    Channel Estimation

    Book Details:
  • Author : Shazib Naveed
  • Publisher : LAP Lambert Academic Publishing
  • Release : 2013
  • ISBN : 9783659393334
  • Pages : 68 pages

Download or read book Channel Estimation written by Shazib Naveed and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: With rapid growth of digital communication in recent years, the need for high speed data transmission is increased. Moreover, future wireless systems are expected to support a wide range of services which includes video, data and voice. OFDM is a promising candidate for achieving high data rates in mobile environment, due to its resistance to ISI, which is a common problem found in high speed data communication. In OFDM, modulation may be differential or coherent. When using differential modulation there is no need for a channel estimate but its performance is inferior to the coherent system. Coherent modulation requires the channel estimation which gives better performance but with relatively more complex receiver structure. Training Symbol Assisted Modulation is used to achieve reliable channel estimates by transmitting Training along with data symbols. In this thesis, Shazib Naveed has analyzed different channel estimation patterns in terms of BER and propose a new scheme for transmitting Training symbols in wireless OFDM systems. Author has also proposed an adaptive scheme of channel estimation in wireless OFDM systems, which track the multi-path fading channel.

Book Fuzzy Systems and Data MiningII

Download or read book Fuzzy Systems and Data MiningII written by S.-L. Sun and published by IOS Press. This book was released on 2016-11-24 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuzzy systems and data mining are now an essential part of information technology and data management, with applications affecting every imaginable aspect of our daily lives. This book contains 81 selected papers from those accepted and presented at the 2nd international conference on Fuzzy Systems and Data Mining (FSDM2016), held in Macau, China, in December 2016. This annual conference focuses on 4 main groups of topics: fuzzy theory, algorithm and system; fuzzy applications; the interdisciplinary field of fuzzy logic and data mining; and data mining, and the event provided a forum where more than 100 qualified, high-level researchers and experts from over 20 countries, including 4 keynote speakers, gathered to create an important platform for researchers and engineers worldwide to engage in academic communication. All the papers collected here present original ideas, methods and results of general significance supported by clear reasoning and compelling evidence, and as such the book represents a valuable and wide ranging reference resource of interest to all those whose work involves fuzzy systems and data mining.

Book Adaptive Channel Estimator Design for OFDM based Wireless Communication Systems

Download or read book Adaptive Channel Estimator Design for OFDM based Wireless Communication Systems written by 黃彥銘 and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Blind Channel Identification and Equalisation of OFDM Systems

Download or read book Blind Channel Identification and Equalisation of OFDM Systems written by Faisal Obaid Hassan Al-Ayyan and published by . This book was released on 2008 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: The possible connections with classical approaches for OFDM system model estimation are also outlined. Using a restoral property of the transmitted communications signals in the absence of the spatial diversity, adaptive algorithms are developed based on the constant modulus principle. The proposed algorithms minimise lSI and F0, and offer faster convergence-rate to satisfy indoor applications. The proposed algorithms are designed based on a zero forcing (ZF) solution which attempts to equalise the channel regardless of its attenuations and noise level. Since the ZF criterion has the potential to amplify noise tremendously, a weak sub-channel will also cause problems. To avoid the ill-conditioning sub-channel, a minimum mean square error (MMSE) solution is proposed. Instead of amplifying the received signal up to a certain level, the MMSE criterion strikes a balance between alleviating lSI and. minimizing noise. Several algorithms based on the MMSE criterion are developed which outperforms the ZF equalisers in the presence of spatial diversity. The aforementioned techniques are based on the insertion of redundant samples in the time domain, known as guard interval (GI), to alleviate lSI. The sub-carriers that are set to zero in the frequency domain without any information are referred to as virtual carriers (VCs). Other than the GI, the presence of VCs provides another useful resource that can be used for channel estimation and lSI mitigation between consecutive OFDM symbols. In this thesis, we present an efficient and simple algorithm to implement channel estimation which is capable of equalising the received signal. Simulation examples are provided to illustrate the characteristics, advantages and limitations of the different methods, and to compare them to existing methods.

Book Subspace Based Semi Blind Channel Estimation in Uplink OFDMA Systems

Download or read book Subspace Based Semi Blind Channel Estimation in Uplink OFDMA Systems written by 潘俊憲 and published by . This book was released on 2008 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: