Myung-Soo Lee

A Novel Decoding Scheme for MIMO Signals Using Combined Depth- and Breadth-First Search and Tree Partitioning

In this paper, we propose a novel ML decoding scheme based on the combination of depth- and breadth-first search methods on a partitioned tree for multiple input multiple output systems. The proposed scheme first partitions the searching tree into several stages, each of which is then searched by a depth- or breadth-first search method, possibly exploiting the advantages of both the depth- and breadth-first search methods in an organized way. Numerical results indicate that, when the depth- and breadth-first search algorithms are adopted appropriately, the proposed scheme exhibits substantially lower computational complexity than conventional ML decoders while maintaining the ML bit error performance.

A Novel ML Decoding Scheme for MIMO Signals

In this paper, we propose a novel maximum-likelihood (ML) decoding scheme based on the combination of depth- and breadth-first search methods on a partitioned tree for multiple input multiple output systems. The proposed scheme first partitions the searching tree into several stages, each of which is then searched by a depth- or breadth-first search method, possibly exploiting the advantages of both the depth- and breadth-first search methods in an organized way. Numerical results indicate that, when the depth- and breadth-first search algorithms are adopted appropriately, the proposed scheme exhibits substantially lower computational complexity than conventional ML decoders while maintaining the ML bit error performance.

Optimal and suboptimal synchronization schemes for ultra-wideband systems

The conventional ultra-wideband (UWB) synchronization schemes could cause poor performance in receiver operations such as demodulation after the synchronization, since unreliable timing information corresponding to low-power multipath components might be transferred to the next stage. To solve this problem, in this paper, we propose novel synchronization schemes for UWB systems. We first derive an optimal scheme based on the maximum likelihood (ML) criterion and then develop a simpler suboptimal scheme. Simulation results show that both proposed schemes provide a better synchronization performance over the conventional scheme.

Enhanced Multiple-Shift Scheme for Rapid Code Acquisition in Optical CDMA Systems

In this paper, we propose a novel code acquisition scheme called enhanced multiple-shift (EMS) for optical code division multiple access (CDMA) systems. By using multiple thresholds, the proposed EMS scheme provides a shorter mean acquisition time (MAT) than that of the conventional mutiple-shift (MS) scheme. The simulation results demonstrate that the MAT of EMS scheme is shorter than that of MS scheme in both single-user and multi-user environments.