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A new method of applying EMD (empirical mode decomposition) algorithm to realize the CFO (carrier frequency offset) estimation of single channel OFDM (orthogonal frequency division multiplexing) system is proposed in this paper. Firstly, the observation signal is extracted by using correlation detection technology to process the received OFDM signal. Then the data with CFO information is obtained...
A new method of orthogonal frequency division multiplexing (OFDM) sparse channel estimation based on compressive sensing (CS) is proposed by exploiting the sparsity property of channel impulse response. One of the CS algorithms, Signal Adaptive Matching Pursuit is used to estimate the channel impulse response of OFDM system. Through compressive sensing process estimation signal can be directly get,...
To achieve diversity with a single antenna, a fractional sampling (FS) scheme in OFDM has been investigated. In addition, to obtain more diversity gain through FS, a sampling point selection (SPS) scheme has been proposed. However, it requires a large number of multiplication operations for the SPS. This leads to large power consumption and costs for additional circuits. In this paper, a low-complexity...
In semi-blind channel estimation techniques, the choice of the regularizing parameter that weights the blind criterion when linearly combined to the training-based least square criterion has a great impact on channel estimation performance. If a scalar regularization is considered, it has been noted that the optimal value of the regularizing factor has no closed-form expression. In a recent work,...
The paper presents an investigation into methods for maximizing the spectral Efficiency of Orthogonal Frequency Division Multiplexing (OFDM) systems. As part of this, an investigation of detrimental effects on OFDM is presented, the use of pilots between carriers, Clipping Distortion, Additive Complex Noise (ACN) on modulation QPSK rate, on multi path Synchronization error, using estimation results...
The existed preamble structure for orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) system requires two zero-value guard symbols to guarantee ISI and ICI avoidance (equivalent to 3/2 complex value symbols in OFDM with cyclic prefix system), which leads to OFDM/OQAM system with low spectrum efficiency. In this paper, we shorten the preamble with 1 zero-value guard symbol to improve the...
In this paper, simultaneous channel estimation, carrier frequency offset (CFO) estimation, and data decision are considered for multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. It is shown that the expectation maximization (EM) approach is complementary to the Kalman filter (KF) approach where the latter provides poor CFO estimation but good channel estimation...
Time-interleaved (TI) analog-to-digital converters (ADCs) are a promising architecture for realizing the highspeed ADCs required to implement "mostly digital" receivers for emerging multiGigabit communication systems. Mismatch between the parallel ADCs comprising a TI-ADC is a fundamental performance bottleneck. While there exist mismatch correction techniques for generic applications of...
In this paper, we address the estimation of carrier frequency offset (CFO) in orthogonal frequency division multiplexing (OFDM) based multiple input multiple output (MIMO) communication systems. One of the novelties of the proposed approach is the judicious combination of two methods so as to reduce the bandwidth overhead and computational complexity without compromising the CFO estimation range....
Orthogonal frequency division multiplexing (OFDM) is a transmission technique which is robust in multipath channels. It is though sensitive to frequency errors that may be caused by several factors such as frequency offset at the local oscillator, phase noise and mobility of the receiver. These errors may destroy orthogonality among subcarriers and introduce intercarrier interference (ICI) that may...
This paper proposes an linear minimum mean square error (LMMSE) channel estimator with maximum ratio combining-based decision directed (MRC-DD) technique to increase spectral efficiency in orthogonal frequency division multiplexing (OFDM) transmit diversity. For Alamouti's transmit diversity, pilot symbols are exclusively allocated in two OFDM symbols on different antennas. This results in serious...
Orthogonal Frequency Division Multiplexing has become a key element of todays wireless communication systems. However, its sensitivity to oscillator phase noise is responsible for common phase error (CPE) and inter-carrier interference (ICI) which greatly degrades the overall system performance. In this contribution, we address the problem of reducing the effects of phase noise in an OFDM system operating...
Orthogonal frequency division multiplexing (OFDM) is an attractive technique for achieving high-bit-rate wireless communications. Phase noise causes constellation rotation, the so called common phase error (CPE), and inter-carrier interference (ICI). In the proposed compensation scheme, we estimate CPE, channel and data by using of linear interpolation method. It is shown by computer simulations that...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H) which is required to operate under high mobility conditions resulting in significant Inter-Carrier Interference (ICI). Under these conditions, the conventional one-tap per subcarrier channel estimation and equalization is suboptimal since it does not account for ICI...
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