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This paper is focusing on the performance of the proposed exponentially weight recursive least square (EW-RLS) and normalized least mean square (NLMS) channel estimator using simulations, in the context of the communication system with MIMO antenna operating in outdoor environments. Different training rates and different Doppler frequencies are used to track time-variations of the channel. Three adaptive...
This paper presented novel Carrier Frequency Offset (CFO) acquisition together with multi-antenna channel estimation algorithms for burst-mode Multiple-Input Multiple-Output combined with Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems. The new algorithms take full advantage of some known channel information (for example, the length of channel impulse response L which can be estimated...
Semi-blind joint CFO, channel estimation and data detection for OFDM systems over doubly selective channels (DSCs) is investigated in this work. A joint iterative algorithm is developed based on the maximum a posteriori expectation-maximization (MAP-EM) algorithm. In addition, a novel algorithm is also proposed to obtain the initial estimates of CFO and channels. Simulation results show that the performance...
It is conventionally supposed that the periodicity of superimposed training (ST) sequence designed for channel estimation has no impact on the ST system's performance, as long as the channel identification condition is satisfied. Accordingly the shortest sequence period equal to channel length is always preferred in ST-OFDM systems for its computational tractability. However, with additional consideration...
Superimposed training (SIT) design for estimating of time-varying multipath channels is investigated for mobile orthogonal frequency division multiplexing (OFDM) systems. The design of sub-optimum SIT consists of two parts: the optimal SIT sequence is derived by minimizing the channel estimates' mean square error (MSE); the sub-optimal power allocation between training and information data is developed...
The combination of multi-input multi-output (MIMO) with orthogonal frequency division multiplexing (OFDM) is regarded as a promising technique for the future wireless communications. However, the performance of MIMO OFDM systems is very sensitive to carrier frequency offset (CFO) which introduces inter-carrier-interference (ICI). Consequently, CFO estimation plays a key role in MIMO OFDM systems....
In order to improve the system performance over both frequency- and time-selective fading channels, orthogonal frequency division multiplexing (OFDM) system with transmit diversity technique is an effective and attractive solution. However, the received signal is the superposition of the signals from different transmit antennas. Hence, to obtain accurate channel state information (CSI) is difficult...
This article researches the channel estimation algorithm based on multi-input multi-output & orthogonal frequency division multiplexing (MIMO-OFDM) system. It is mainly working on the research of channel estimation algorithm based on training sequence least square (LS) criterion. On the basis of introducing the LS time domain channel estimation algorithm, it brings about an improved LS time domain...
Channel estimation and data detection are investigated for OFDM systems over time- and frequency-selective (doubly selective) channels. Relying on the complex exponential basis expansion channel model, a pilot embedded channel estimation scheme with low computational complexity and high data rate efficiency is proposed. An iterative edition exploiting recovered data to enhance the performance is also...
Frame timing and carrier frequency offsets in orthogonal frequency division multiplexing (OFDM) may drastically degrade performance if not accurately compensated. In practice, these offsets are estimated by transmitting a training block at the beginning of each frame. By designing this training block to have a repetitive structure, various estimation methods have been proposed in the literature. These...
Effects of improved channel estimation are studied for a proposed IEEE 802.11n OFDM MIMO system. Three channel estimation methods are considered: maximum likelihood (ML), time-domain truncation (TDT) and model-based (MB). TDT and MB are particularly useful when the channel delay spread is short. For an MMSE receiver, MB shows a 1-2.5 dB improvement over ML on the packet error rate performance for...
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