Boon Sim Thian

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We consider robust receiver design in uncoded multiple-input multiple-output (MIMO) wireless communication systems. In practical systems, the channel state information (CSI) available at the receiver is often imperfect due to measurement errors, quantization errors and many other sources of errors. Consequently, using the erroneous CSI for decoding the(More)
We consider the problem of maximum likelihood (ML) signal detection in multiple-input multiple-output (MIMO) wireless communication systems. We propose a new preprocessing algorithm in the form of channel ordering for sphere decoders. Numerical results show that this new channel ordering leads to significantly lower complexity (in the form of the number of(More)
We consider transceiver design in uncoded multiple-input multiple-output (MIMO) systems with noisy channel state estimates. Specifically, we design a transceiver that takes into account the statistics of the CSI errors red to minimize the average bit average rate (BER) of the system. Our design utilizes the noisy CSI estimates and the error statistics at(More)
We describe Wireless Network Utility Maximization, WNUM, and compare its performance to NUM for wireless networks of interfering links under random time varying channel conditions. WNUM is shown to simultaneously offer greater rate and reliability performance in simulations operating under Rayleigh fading. A general method for finding adaptive network(More)
In this paper, we develop a signal model for the transmission of discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-SOFDM) in a frequency selective channel. Although maximum likelihood (ML) estimation of the transmitted signal in the DFT-SOFDM system gives the optimum bit-error rate (BER) performance, it incurs exponential(More)
We propose a robust near maximum-likelihood (ML) decoding metric that is robust to channel estimation errors and is near optimal with respect to symbol error rate (SER). The solution involves an exhaustive search through all possible transmitted signal vectors; this search has exponential complexity, which is undesirable in practical systems. Hence, we also(More)
We consider receiver design in uncoded multiple-input multiple-output (MIMO) wireless communication systems. Practical MIMO systems assume an accurate estimate of the channel state information (CSI) at the receiver; failure to estimate the channel accurately or to account for CSI errors in the receiver leads to poor performance in terms of high symbol error(More)
The transmission of a Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-SOFDM) signal through a time-selective fading channel suffers from severe performance degradation due to the Doppler shifting of the transmitted spectrum. In this paper, we propose a multiple-input multiple-output (MIMO) DFT-SOFDM scheme and a new(More)
In this paper, we develop and present a DFT-SOFDM system (operating in both distributed and localized FDMA modes) for transmission and reception through a frequency-selective, slow fading channel. This system allows us to use well-known linear receiver techniques such as the zero-forcing (ZF) and minimum mean-squared error (MMSE) equalization. More(More)
Obtaining accurate instantaneous channel state information (CSI) is challenging for multiple-input-multiple-output (MIMO) systems, particularly if the channel fluctuates rapidly. A more practical assumption is statistical CSI as the channel statistics are likely to remain unchanged for a longer period. In this letter, we propose a precoder design, using(More)