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In this paper, we focus on full–rate, fast–decodable space–time block codes (STBCs) for 2×2 and 4×2multiple-input multiple-output (MIMO) transmission. We first derive conditions for reduced-complexity maximum-likelihood decoding, and apply them to a unified analysis of two families of 2 × 2 STBCs that were recently proposed. In particular, we describe a(More)
This paper describes a novel feature selection algorithm for unsupervised clustering, that combines the clustering ensembles method and the population based incremental learning algorithm. The main idea of the proposed unsupervised feature selection algorithm is to search for a subset of all features such that the clustering algorithm trained on this(More)
Unipolar communications systems can transmit information using only real and positive signals. This includes a variety of physical channels ranging from optical (fiber or free-space), to RF wireless using amplitude modulation with non-coherent reception, to baseband single wire communications. Unipolar OFDM techniques enable to efficiently compensate(More)
We consider two uniploar OFDM techniques for optical wireless communications: asymmetric clipped optical OFDM (ACO-OFDM) and Flip-OFDM. Both techniques can be used to compensate multipath distortion effects in optical wireless channels. However, ACO-OFDM has been widely studied in the literature, while the performance of Flip-OFDM has never been(More)
In this paper, we present a multidimensional trellis coded modulation scheme for a high rate 2 2 multiple-input multiple-output system over slow fading channels. Set partitioning of the Golden code [9] is designed speci cally to increase the minimum determinant. The branches of the outer trellis code are labeled with these partitions and Viterbi algorithm(More)
We consider a slow fading multiple-input multiple-output (MIMO) system with channel state information at both the transmitter and receiver. A well-known precoding scheme is based upon the singular value decomposition (SVD) of the channel matrix, which transforms the MIMO channel into parallel subchannels. Despite having low maximum likelihood decoding (MLD)(More)
New space–time turbo trellis codes (ST turbo TCs) with 4-phase-shift keying (PSK) and 8-PSK for two, three, and four transmit antennas in slow and fast fading channels are proposed in this paper. The component codes of the space–time turbo schemes are constructed by choosing the feedforward coefficients to maximize the minimum squared Euclidean distance and(More)
A key issue in compute-and-forward for physical layer network coding scheme is to determine a good function of the received messages to be reliably estimated at the relay nodes. We show that this optimization problem can be viewed as the problem of finding the closest point of Z[i]<sup>n</sup> to a line in the n-dimensional complex Euclidean space, within a(More)