The synchronisation in wireless cooperative relay networks is impossible to achieve in real environment utilising orthogonal space time block coding. There have been several approaches proposed to mitigate the effect ...
详细信息
The synchronisation in wireless cooperative relay networks is impossible to achieve in real environment utilising orthogonal space time block coding. There have been several approaches proposed to mitigate the effect of synchronisation among the relay nodes at the receiver. All have managed to reduce the inter-symbol interference at the expense of low data rate with high detection complexity. Others achieved full data rate and high cooperative diversity using high decoding complexity that requires a feedback link. In this paper, a new approach is presented that reduces inter-symbol interference, achieves full data rate and full cooperative diversity with low complexity. This uses a new efficient distributed orthogonal space time block coding design with a sub-optimum detection scheme utilising dual relay nodes. This reduces the number of timing misalignments among the relay nodes and minimises the detection complexity. Furthermore, the new proposed method uses linear decoding process to achieve full data rate and full cooperative diversity without the need for any a feedback link. The analytical analysis and simulation results confirmed that sub-optimum approach with the new efficient design are very effective at reducing the lack of synchronisation among the relay nodes at the destination node with low encoding and decoding complexities.
This paper presents a sparse code multiple access (SCMA) system with massive antennas at the base station. This system is referred to as M-SCMA system. A spectrally-efficient and massive access next-generation wireles...
详细信息
This paper presents a sparse code multiple access (SCMA) system with massive antennas at the base station. This system is referred to as M-SCMA system. A spectrally-efficient and massive access next-generation wireless network is realized through massive antennas and non-orthogonal SCMA techniques. Two detection algorithms, namely, modified message passing algorithm (MMPA) and extended message passing algorithm (EMPA) are proposed to detect multiple users' symbols in M-SCMA. A deep learning (DL)-based detection scheme is also proposed for M-SCMA so as to avoid channel estimation and to lower the detection complexity. Numerical results show that the DL-based detection has similar performance as MMPA even when the channel information is not estimated explicitly. Furthermore, authors also establish the sum rate trade-off between SCMA and orthogonal multiple access in a massive antenna system. The impact of various M-SCMA parameters such as the number of antennas and the overloading factor, on the proposed DL, MMPA, and EMPA-based detection are also investigated.
Multiple input-multiple output (MIMO) is a key enabling technology for the next generation of wireless communication systems. However, one of the main challenges in the implementation of MIMO system is the complexity ...
详细信息
Multiple input-multiple output (MIMO) is a key enabling technology for the next generation of wireless communication systems. However, one of the main challenges in the implementation of MIMO system is the complexity of the detectors when the number of antennas increases. This aspect will be crucial in the implementation of future massive MIMO systems. A flexible design can offer a convenient tradeoff between detection complexity and bit error rate (BER). Deep learning (DL) has emerged as an efficient method for solving optimization problems in different areas. In MIMO communication systems, neural networks can provide efficient and innovative solutions. This paper presents an efficient DL-based signal detection strategy for MIMO communication systems. More specifically, a preprocessing stage is added to label the input signals. The labeling scheme provides more information about the transmitted symbols for better training. Based on this strategy, two novel schemes are proposed and evaluated considering BER performance and detection complexity. The performance of the proposed schemes is compared with the conventional one-hot (OH) scheme and the optimal maximum likelihood (ML) criterion. The results show that the proposed OH per antenna (OHA) and direct symbol encoding (DSE) schemes reach a classification performance F1-score of 0.97. Both schemes present a lower complexity compared with the conventional OH and the ML schemes, used as references. On the other hand, the OHA and DSE schemes have losses of less than 1 dB and 2 dB in BER performance, respectively, compared to the OH scheme. The proposed strategy can be applied to adaptive systems where computational resources are limited.
A unified tree-search detection scheme based on Dijkstra's algorithm is developed for MIMO systems. The proposed framework generalizes the original Dijkstra's algorithm by allowing the memory usage, detection ...
详细信息
ISBN:
(纸本)9781424492688
A unified tree-search detection scheme based on Dijkstra's algorithm is developed for MIMO systems. The proposed framework generalizes the original Dijkstra's algorithm by allowing the memory usage, detection complexity, and sorting dynamic associated with the algorithm to be customized. By tuning different parameters, desired performance-complexity tradeoffs are attained and a fixed-complexity version can be produced to facilitate hardware implementation. Simulation results demonstrate that the proposed algorithm shows abilities to achieve highly favorable performance-complexity tradeoffs.
SC-based index modulation (SC-IM) is a recently developed communication scheme that uses the optimal high complexity maximum likelihood (ML) detection algorithm at receiver. In this paper, we propose a single-carrier-...
详细信息
ISBN:
(纸本)9781728150093
SC-based index modulation (SC-IM) is a recently developed communication scheme that uses the optimal high complexity maximum likelihood (ML) detection algorithm at receiver. In this paper, we propose a single-carrier-based generalize time-domain index modulation (GTD-IM) scheme whose receiver employs a square-law envelope detector (SLED) to detect the active indices. Through analyses and simulations, we find that this system can achieve approximate energy efficiency and error performance of SC-IM with a lower implementation complexity.
Despite of the known gap from the Shannon's capacity, several standards are still employing QAM or star shape constellations, mainly due to the existing low complexity detectors. In this paper, we investigate the ...
详细信息
ISBN:
(纸本)9781509050192
Despite of the known gap from the Shannon's capacity, several standards are still employing QAM or star shape constellations, mainly due to the existing low complexity detectors. In this paper, we investigate the low complexitydetection for a family of QAM isomorphic constellations. These constellations are known to perform very close to the peakpower limited capacity, outperforming the DVB-S2X standard constellations. The proposed strategy is to first remap the received signals to the QAM constellation using the existing isomorphism and then break the log likelihood ratio computations to two one dimensional PAM constellations. Gains larger than 0.6 dB with respect to QAM can be obtained over the peak power limited channels without any increase in detection complexity. Our scheme also provides a systematic way to design constellations with low complexity one dimensional detectors. Several open problems are discussed at the end of the paper.
In this paper, we introduce, a new method named "complexity Reduction Method based on Compensation Distance" in order to reduce the complexity of the detection in virtual layered space-time receivers in mult...
详细信息
ISBN:
(纸本)9781424480166
In this paper, we introduce, a new method named "complexity Reduction Method based on Compensation Distance" in order to reduce the complexity of the detection in virtual layered space-time receivers in multiple-input multiple-output (MIMO) systems. Moreover, this method is practical even when the number of transmitting streams is greater than that of receiving antennas. Computer simulations indicate that the proposed method can be used to reduce the complexity of detection to approximately 20 in [8 4] (the transmitter is equipped with 8 antennas and the receiver is equipped with 4 antennas) systems.
For Massive multiple-input multiple output (MIMO) systems, many algorithms have been proposed for detecting spatially multiplexed signals, such as reactive tabu search (RTS), minimum mean square error (MMSE), etc. As ...
详细信息
For Massive multiple-input multiple output (MIMO) systems, many algorithms have been proposed for detecting spatially multiplexed signals, such as reactive tabu search (RTS), minimum mean square error (MMSE), etc. As a heuristic neighborhood search algorithm, RTS is particularly suitable for signal detection in systems with large number of antennas. In this paper, we propose a strategy to reduce the neighborhood searching space of the traditional RTS algorithms. For this, we introduce a constellation constraints (CC) structure to determine whether including a candidate vector into the RTS searching neighborhood. By setting a pre-defined threshold on the symbol constellation, the Euclidean distance between the estimated signal and its nearest constellation points are calculated, and the threshold and distance are compared to separate the reliable estimated signal from unreliable ones. With this structure, the proposed CC-RTS algorithm may ignore a significant number of unnecessary candidates in the RTS neighborhood searching space and greatly reduce the computational complexity of the traditional RTS algorithm. Simulation results show that the BER performance of the proposed CC-RTS algorithm is very close to that of the traditional RTS algorithm, and with about 50% complexity reduction with the same signal-to-noise (SNR) ratio.
Spatial modulation (SM) is an efficient transmission scheme based on multiple-input multiple-output systems. SM, by nature, requires coherent detection to achieve optimal error performance. This requires that the rece...
详细信息
Spatial modulation (SM) is an efficient transmission scheme based on multiple-input multiple-output systems. SM, by nature, requires coherent detection to achieve optimal error performance. This requires that the receiver has full knowledge of the channel state information (CSI), however, determining the CSI results in an increase in the detection complexity at the receiver. Differential modulation systems are capable of performing detection without knowledge of the CSI at the receiver, however, they suffer a 3dB error performance penalty as compared to their coherent counterparts. In this study, the authors present a generalised differential scheme for SM (GD-SM) based on generalised differential modulation, which is capable of reducing the performance penalty incurred through optimal power allocation. Furthermore, they extend the architecture of GD-SM and optimal power allocation to conventional differential SM. The architecture of the proposed systems, advantageously permits the use of either M-ary quadrature amplitude modulation or M-ary phase shift keying constellations. Simulation and theoretical results demonstrate that GD-SM incurs only about 0.5dB performance loss as compared to coherent SM when the frame length is 400.
In this paper,a differential scheme is proposed for reconfigurable intelligent surface(RIS)assisted spatial modulation,which is referred to as RISDSM,to eliminate the need for channel state information(CSI)at the *** ...
详细信息
In this paper,a differential scheme is proposed for reconfigurable intelligent surface(RIS)assisted spatial modulation,which is referred to as RISDSM,to eliminate the need for channel state information(CSI)at the *** proposed scheme is an improvement over the current differential modulation scheme used in RIS-based systems,as it avoids the high-order matrix calculation and improves the spectral efficiency.A mathematical framework is developed to determine the theoretical average bit error probability(ABEP)of the system using *** detection complexity of the proposed RIS-DSM scheme is extremely low through the ***,simulations results demonstrate that the proposed RIS-DSM scheme can deliver satisfactory error performance even in low signal-to-noise ratio environments.
暂无评论