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A modified sphere decoding (SD) scheme is proposed for multiple-input multiple-output (MIMO) communication systems in this paper. The conventional SD goes from the lower dimension to the higher dimension to examine whether a lattice point lies inside the sphere of some radius, which remains fixed for all dimensions. Since the sphere radius directly affects the search range and thus the complexity,...
In this paper, we are concerned with low-complexity detection in large multiple-input multiple-output (MIMO) systems with tens of transmit/receive antennas. Our new contributions in this paper are two-fold. First, we propose a low-complexity algorithm for large-MIMO detection based on a layered low-complexity local neighborhood search. Second, we obtain a lower bound on the maximum-likelihood (ML)...
In this paper a novel detection algorithm for spatial modulation (SM) based on sphere decoder (SD) tree search idea is proposed. The aim is to reduce the receiver complexity of the existing optimal decoder while maintaining an optimum performance. The algorithm performs a maximum likelihood (ML) search, only over those points that lie inside a sphere, centered at the received signal, of given radius...
Multiple-input multiple-output (MIMO) single carrier frequency division multiple access (SC-FDMA), which combines the advantage of spatial and frequency diversities with frequency domain equalizers (FDE), has drawn great attention recently. Among all possible detection techniques, maximum-likelihood detection (MLD) is optimal, but its exponentially computational complexity precludes its use in practical...
In this paper, we propose a maximum likelihood (ML) decoder for differentially encoded orthogonal spacetime block codes (OSTBCs) based on multiple received data blocks. The proposed ML decoder differs from the existing ML decoders of differential OSTBC as follows: 1) Most existing ML decoders are derived on the basis of two consecutively received data matrices, whereas the proposed decoder takes multiple...
In MIMO communication systems maximum-likelihood (ML) decoding can be formulated as a tree-searching problem. This paper presents a tree-searching approach that combines the features of classical depth-first and breadth-first approaches to achieve close to ML performance while minimizing the number of visited nodes. A detailed outline of the algorithm is given, including the required storage. The...
In this paper, we derive a theoretical performance evaluation scheme of Kalman filter based channel tracking and data decoding for multiple-input multiple-output orthogonal frequency division multiplexed (MIMO-OFDM) communication systems that are based on orthogonal space-time block codes. The derivation is approximate, however, it is novel and demonstrated accurate for practical scenarios. Assuming...
This paper proposes a structure that combines iterative equalization and turbo decoding, denoted as spatial turbo coding (STC), for single carrier signaling to achieve near capacity performance in multipath-rich fading channels. Instead of multiplexing the encoded bits in the time domain as in the standard turbo codes, the proposed STC transmits coded bits in the space domain by employing multiple-input...
This paper presents a K-Best decoding algorithm that requires a much smaller K while preserving advantages of the sphere decoding algorithm such as branch pruning and an adaptively updated pruning threshold. The proposed approach results in examining a much smaller set of modulation points with a significantly reduced complexity. Simulations are presented that quantify the BER performance and complexity...
We propose a pragmatic labeling design based on the extrinsic information transfer (EXIT) chart for bit-interleaved coded modulation with iterative decoding on multiple-input-multiple-output channels. In our design, the EXIT chart is used to determine a candidate set of labelings which have representative demapper transfer curves. Then, a procedure to generate these labelings is provided based on...
In this paper, we propose a Differential Linear Dispersion Coded (DLDC) cooperative transmission scheme suitable for Vehicular Ad Hoc NETworks (VANETs), which facilitates striking a flexible diversity-multiplexing gain tradeoff without requiring channel estimation both at the cooperating nodes and at the destination node. More specifically, DLDC encoding is employed by the source transmitter for broadcasting...
This paper considers amplify-and-forward (AF) relaying systems with multiple relay nodes between the source and the destination node, where all nodes are equipped with multiple antennas. Using multiple relay nodes to transmit a message, a distributed diversity gain can be obtained. In this paper, we address the optimization problem of relay weighting matrices which minimizes the mean-square-error...
Non-orthogonal space-time block codes (STBC) from cyclic division algebras (CDA) are attractive because they can simultaneously achieve both high spectral efficiencies (same spectral efficiency as in V-BLAST for a given number of transmit antennas) as well as full transmit diversity. Decoding of non-orthogonal STBCs with hundreds of dimensions has been a challenge. In this paper, we present a probabilistic...
Recently, researches on space-time codes deploying multiple transmit and receive antennas have abruptly emerged due to its potential to greatly improve spectral efficiency. Particularly, space-time bit-interleaved coded modulation (ST-BICM) gives rise to very reliable bit error rate (BER) performance with quite flexible rate compatibility. In this paper, we propose an iterative linear minimum-mean-squared-error...
Multi-input multi-output (MIMO) receivers have generally been designed and their communication performance analyzed under the assumption of additive Gaussian noise. Wireless transceivers, however, may also be affected by radio frequency interference (RFI) that is well modeled using non-Gaussian impulsive statistics. In this paper, we derive bounds on the communication performance for a two transmit,...
When channel state information is not available, combined unitary space-time modulation and parallel concatenated convolutional code can greatly improve the system performance, however it also meet with the error floor phenomenon. We propose a scheme of utilizing unitary space-time symbol based serial concatenated convolutional code for multiple-antenna wireless communication systems over rapid fading...
The complex sphere decoding algorithm has optimal bit error ratio performance for uncoded multiple-input multiple-output (MIMO) systems. The computational and hardware complexities of this algorithm increase significantly for detection of 64-QAM modulated signal streams. In this paper two modifications to the original sphere decoding algorithm are proposed that reduce both computational complexity...
DSTBC (differential space-time block coding) system does not require CSI (channel state information) in both transmitter and receiver sides, but its SNR (signal to noise ratio) versus BER (bit error rate) characteristic is degraded compared with original STBC scheme which utilizes CSI at the receiver. In this paper, attempting to recover this performance loss originated from the differential decoding,...
In this paper we evaluate the performance of a multi stage receiver for coded signals (using space time block codes) when MIMO (multi input multi output) channels are employed. This provides a new paradigm for transmission over Rayleigh fading channels where scattering phenomenon is a major obstruction. At the transmitter side data encoded using a space-time block code, and the encoded data is split...
In this paper, we proposed a joint design scheme between sphere decoding and user scheduling for multiuser MIMO uplink system. This is a cross layer design scheme which adopt the channel quality information based on user scheduling to reduced the search radius of sphere detector, it leads the better bit error ratio performance and low complexity than conventional sphere detection with fixed search...
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