The QR decomposition-based m (QRD-m) algorithm is a suboptimal detection algorithm that achieves near-maximum-likelihood detection (mLD) performance with low complexity. Some conventional QRD-malgorithms that directl...
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The QR decomposition-based m (QRD-m) algorithm is a suboptimal detection algorithm that achieves near-maximum-likelihood detection (mLD) performance with low complexity. Some conventional QRD-malgorithms that directly determine the number of surviving paths have simple structures and are consequently cost effective and easy to implement. However, it is possible that surviving paths are chosen that have unnecessarily low reliability. The authors propose an algorithm, termed signal position-based QRD-m, to solve this problem using position estimation of the received signal. The position estimation process is accomplished using the most reliable candidate symbol to minimise additional processing. Computer simulations demonstrated that the proposed algorithm can achieve near-mLD performance with lower complexity than the fixed QRD-malgorithm.
In this paper, the partial interference cancellation receiver with successive interference cancellation (PIC-R-SIC) in the spatial modulation (Sm) aided zero-padded single-carrier transmission is studied, and two comp...
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ISBN:
(纸本)9781467376877
In this paper, the partial interference cancellation receiver with successive interference cancellation (PIC-R-SIC) in the spatial modulation (Sm) aided zero-padded single-carrier transmission is studied, and two complexity reduction methods are presented by employing the Toeplitz structure of the channel matrix. Specifically, a shorten PIC-R-SIC (S-PIC-R-SIC) is first proposed, where, for each symbol detection, the equivalent channel matrix size is reduced. This method has much lower complexity than the conventional PIC-R-SIC with a cost of performance degradation. Next, the combining of S-PIC-R-SIC with m-algorithm is considered to improve the performance. Simulation results shown that the combined method can achieve better performance while lower complexity than the conventional PIC-R-SIC.
This paper presents a novel low-complexity multiple-input multiple-output (mImO) detection scheme using a distributed m-algorithm (Dm) to achieve high performance soft mImO detection. To reduce the searching complexit...
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ISBN:
(纸本)9781424442966
This paper presents a novel low-complexity multiple-input multiple-output (mImO) detection scheme using a distributed m-algorithm (Dm) to achieve high performance soft mImO detection. To reduce the searching complexity, we build a mImO trellis graph and split the searching operations among different nodes, where each node will apply the m-algorithm. Instead of keeping a global candidate list as the traditional detector does, this algorithm keeps multiple small candidate lists to generate soft information. Since the Dmalgorithm can achieve good BER performance with a small m, the sorting cost of the Dmalgorithm is lower than that of the conventional K-best mImO algorithm. The proposed algorithm is very suitable for high speed parallel processing.
QR decomposition and m-algorithm based near maximum likelihood block detection (QRm-mLBD) significantly improves the single-carrier (SC) multiple-input multiple-output (SC-mImO) transmission performance in a frequency...
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QR decomposition and m-algorithm based near maximum likelihood block detection (QRm-mLBD) significantly improves the single-carrier (SC) multiple-input multiple-output (SC-mImO) transmission performance in a frequency-selective fading channel. In the conventional QRm-mLBD, the cyclic prefix (CP) is inserted in order to avoid the inter-block interference (IBI). However, CP insertion reduces the transmission efficiency. In this paper, an iterative overlap QRm-mLBD is proposed for SC-mImO transmission with no CP insertion. It is confirmed by computer simulation that the iterative overlap QRm-mLBD with no CP insertion provides improved throughput performance while reducing the computational complexity over the conventional QRm-mLBD with CP insertion.
With the development of the high-speed communication channel or high-capacity storage device, the intersymbol interference (ISI) occurs more frequently in the condensed data. The traditional Bahl – Cocke – Jelineu ...
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With the development of the high-speed communication channel or high-capacity storage device, the intersymbol interference (ISI) occurs more frequently in the condensed data. The traditional Bahl – Cocke – Jelineu – Raviv (BCJR) method is capable of solving the two-dimensional (2D) symbol influence problem with extremely high cost. By analysing the complexity in terms of branch, state and path in the 2D trellis-based ISI detection, the authors verify that the system complexity is mainly dominated by the window size. To reduce the detection complexity, the conventional simplifications are applied in the 2D strip-wise ISI detection. In addition, a two-phase strip-wise detection is proposed to achieve a lower complexity than that of the conventional simplifications. In this system, the first detector can be realised by a low-complexity method (like the hard detection or Viterbi algorithm) to provide the mask shrinking with predicted data. After reducing the mask size, the second detector can detect the main portion of ISI by the trellis-based detection (like BCJR algorithm) with a small mask. Under the similar detection performance, the proposed scheme can achieve more than 91.76% saving in the metric computation compared with the 5 × 3-window IRCSDFA (iterative row–column soft-decision feedback algorithm) simplified by the m -algorithm with m = 8.
The research of finding better ways for multiple-input multiple-output (mImO) signal detection is important and still goes on. In this paper, we propose a low-complexity mImO detection method mainly with basic and har...
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ISBN:
(纸本)9781479958320
The research of finding better ways for multiple-input multiple-output (mImO) signal detection is important and still goes on. In this paper, we propose a low-complexity mImO detection method mainly with basic and hardware-friendly operations, i.e., zero-forcing (ZF), successive interference cancelation (SIC), double-symbol maximum likelihood (mL) detection, and m-algorithm. We show that it can approach the optimal error rate employing quadrature phase-shift keying (QPSK) signals with affordable complexity in many cases. Simulation results show that in terms of giving a good trade-off between the error rate and implementation complexity, the proposed detection schemes can significantly outperform some contemporary detectors, including the ordered SIC-ZF method and the conventional mL detector employing QR-decomposition and m-algorithm (QRm-mLD), and own an error rate quite close to that of the optimal mL detector.
This paper presents a novel low-complexity multiple-input multiple-output (mImO) detection scheme using a distributed m-algorithm (Dm) to achieve high performance soft mImO detection. To reduce the searching complexit...
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ISBN:
(纸本)9781424442959
This paper presents a novel low-complexity multiple-input multiple-output (mImO) detection scheme using a distributed m-algorithm (Dm) to achieve high performance soft mImO detection. To reduce the searching complexity, we build a mImO trellis graph and split the searching operations among different nodes, where each node will apply the m-algorithm. Instead of keeping a global candidate list as the traditional detector does, this algorithm keeps multiple small candidate lists to generate soft information. Since the Dmalgorithm can achieve good BER performance with a small m, the sorting cost of the Dmalgorithm is lower than that of the conventional K-best mImO algorithm. The proposed algorithm is very suitable for high speed parallel processing.
Combating the intersymbol interference is an important issue in single-carrier block transmission systems. In this paper, we present a nonlinear equalizer that combines frequency-domain (FD) pre-filtering with time-do...
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ISBN:
(纸本)9781479928941
Combating the intersymbol interference is an important issue in single-carrier block transmission systems. In this paper, we present a nonlinear equalizer that combines frequency-domain (FD) pre-filtering with time-domain tree search detection. Simulation results show that the proposed algorithm achieves a detection performance that is very close to that of the conventional tree search equalizer (which employs the QRD-malgorithm), but with a much lower complexity. In addition, the proposed algorithm performs significantly better than the linear equalizers and decision-feedback equalizers, with only a modest increase in complexity.
This paper proposes an adaptive selection algorithm for the surviving symbol replica candidates (ASESS) based on the maximum reliability in maximum likelihood detection with QR decomposition and the m-algorithm (QRm-m...
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This paper proposes an adaptive selection algorithm for the surviving symbol replica candidates (ASESS) based on the maximum reliability in maximum likelihood detection with QR decomposition and the m-algorithm (QRm-mLD) for Orthogonal Frequency Division multiplexing (OFDm) multiple-input multiple-output (mImO) multiplexing. In the proposed algorithm, symbol replica candidates newly-added at each stage are ranked for each surviving symbol replica from the previous stage using multiple quadrant detection. Then, branch metrics are calculated only for the minimum number of symbol replica candidates with a high level of reliability using an iterative loop based on symbol ranking results. Computer simulation results show that the computational complexity of the QRm-mLD employing the proposed ASESS algorithm is reduced to approximately 1/4 and 1/1200 compared to that of the original QRm-mLD and that of the conventional mLD with squared Euclidian distance calculations for all symbol replica candidates, respectively, assuming the identical achievable average packet error rate (PER) performance in 4-by-4 mImO multiplexing with 16QAm data modulation. The results also show that 1-Gbps throughput is achieved at the average received signal energy per bit-to-noise power spectrum density ratio (E-b/N-0) per receiver antenna of approximately 9 dB using the ASESS algorithm in QRm-mLD associated with 16QAmmodulation and Turbo coding with the coding rate of 8/9 assuming a 100-mHz bandwidth for a 12-path Rayleigh fading channel (root mean square (r.m.s.) delay spread of 0.26 mu s and maximum Doppler frequency of 20 Hz).
This paper investigates joint design and optimization of both low density parity check （LDPC） codes and m-algorithm based detectors including iterative tree search （ITS） and soft-output m-algorithm （SOmA） in mul...
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This paper investigates joint design and optimization of both low density parity check （LDPC） codes and m-algorithm based detectors including iterative tree search （ITS） and soft-output m-algorithm （SOmA） in multiple-input multiple-output （mImO） systems via the tool of extrinsic information transfer （EXIT） charts. First, we present EXIT analysis for ITS and SOmA. We indicate that the extrinsic information transfer curves of ITS obtained by monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOmA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in mImO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes performmuch better than standard non-optimized ones when used together with SOmA detector.
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