scholarly journals Low-Complexity Address Generation for Multiuser Detectors in IDMA Systems

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2069
Author(s):  
Byeong Yong Kong
Keyword(s):  
Multiple Access ◽  
Low Complexity ◽  
Cmos Process ◽  
Hardware Complexity ◽  
Multiuser Detectors ◽  
Multiuser Detector ◽  
Gate Count ◽  
Address Generation ◽  
First Time ◽  
Generation Unit

This paper presents a low-complexity address generation unit (AGU) for multiuser detectors in interleave division multiple access (IDMA) systems. To this end, for the first time, all possible options for designing AGUs are first analyzed in detail. Subsequently, a complexity reduction technique is applied to each of those architectures. More specifically, some components in AGUs are relocated to make them shareable and removable without affecting the functionality. The complete transparency of such renovation makes it applicable to any existing multiuser detector without tailoring the interfacing components therein. Measuring the hardware complexity, all the resulting AGUs are compared with each other, and a new architecture simpler than the state-of-the-art one is developed. Implementation results in a 65 nm CMOS process, demonstrating that the proposed AGU can alleviate the equivalent gate count and the power consumption of the prior process by 13% and 31%, respectively.

Novel Scheme for Multiple-Access Interference Mitigation with Low Complexity

2011 ◽  
Vol 143-144 ◽  
pp. 371-375
Author(s):  
Zuo Liang Yin ◽  
Hui Xiao Ma ◽  
Xing Peng Mao ◽  
Jun Cai
Keyword(s):  
Multiple Access ◽  
Interference Mitigation ◽  
Multiple Access Interference ◽  
Low Complexity ◽  
System Capacity ◽  
Error Performance ◽  
Multiuser Detector ◽  
Access Scheme ◽  
Lower Complexity

To mitigate multiple access interference and improve the system capacity, an effective multiple access scheme, called GCDMA, is proposed. Exploiting the IDMA iterative multiuser detector in each group, the intra-group interference can be effectively handled. Analysis and simulations demonstrate that the proposed technique outperforms the conventional CDMA in terms of both system capacity and bit error performance. Lower complexity of the proposed scheme can be achieved than CDMA and even IDMA.

NOVEL LOW-COMPLEXITY ANT COLONY BASED MULTIUSER DETECTOR FOR DIRECT SEQUENCE CODE DIVISION MULTIPLE ACCESS

2005 ◽  
Vol 05 (02) ◽  
pp. 201-214 ◽  
Author(s):  
SAMER L. HIJAZI ◽  
BALASUBRAMANIAM NATARAJAN
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Low Complexity ◽  
Foraging Strategy ◽  
Ant Colony ◽  
Direct Sequence ◽  
Multiuser Detector ◽  
Sequence Code ◽  
Cooperative Foraging ◽  
Code Division Multiple

In this paper, we present a novel multiuser detection (MUD) technique based on ant colony optimisation (ACO), for synchronous direct sequence code division multiple access systems. ACO algorithms are based on the cooperative foraging strategy of real ants. While an optimal MUD design using an exhaustive search method is prohibitively complex, we show that the ACO-based MUD converges to the optimal bit-error-rate performance in relatively few iterations providing 95% savings in computational complexity. This reduction in complexity is retained even when considering users with unequal received powers.

scholarly journals Limited-Search Chase Decoding Algorithm for LDPC Coded Underwater Acoustic Multiuser Channels

2021 ◽  
pp. 76-81
Author(s):  
Xingming Li ◽  
◽  
Zhiliang Qin ◽  
Yuanhao Sun ◽  
Qidong Lu ◽  
...  
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Low Complexity ◽  
Underwater Acoustic ◽  
Correlated Channels ◽  
Multiuser Detector ◽  
Acoustic Networks ◽  
Lower Complexity ◽  
Highly Correlated ◽  
Code Division Multiple

In this paper, we propose a low-complexity soft-input/soft-output (SISO) Chase multiuser detector that has a polynomial computational complexity in terms of the number of the least reliable bit positions for low-density parity-check (LDPC) coded code-division multiple-access (CDMA) systems, which is a potentially competitive technology for underwater acoustic networks (UWAN). Simulation results over highly correlated channels show that the proposed detector can afford searching over a larger number of the least reliable bit positions and achieve better bit-error-rate (BER) performance as compared with the Chase-II detector at much lower complexity.

scholarly journals Low-complexity sparse-aware multiuser detection for large-scale MIMO systems

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Rong Ran ◽  
Hayoung Oh
Keyword(s):  
Large Scale ◽  
Mimo Systems ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
Low Complexity ◽  
Finite Alphabet ◽  
Multiuser Detectors ◽  
Input Multiple Output ◽  
Error Detector ◽  
Significant Performance

AbstractSparse-aware (SA) detectors have attracted a lot attention due to its significant performance and low-complexity, in particular for large-scale multiple-input multiple-output (MIMO) systems. Similar to the conventional multiuser detectors, the nonlinear or compressive sensing based SA detectors provide the better performance but are not appropriate for the overdetermined multiuser MIMO systems in sense of power and time consumption. The linear SA detector provides a more elegant tradeoff between performance and complexity compared to the nonlinear ones. However, the major limitation of the linear SA detector is that, as the zero-forcing or minimum mean square error detector, it was derived by relaxing the finite-alphabet constraints, and therefore its performance is still sub-optimal. In this paper, we propose a novel SA detector, named single-dimensional search-based SA (SDSB-SA) detector, for overdetermined uplink MIMO systems. The proposed SDSB-SA detector adheres to the finite-alphabet constraints so that it outperforms the conventional linear SA detector, in particular, in high SNR regime. Meanwhile, the proposed detector follows a single-dimensional search manner, so it has a very low computational complexity which is feasible for light-ware Internet of Thing devices for ultra-reliable low-latency communication. Numerical results show that the the proposed SDSB-SA detector provides a relatively better tradeoff between the performance and complexity compared with several existing detectors.

EXIT-Chart-Aided Hybrid Multiuser Detector for Multicarrier Interleave-Division Multiple Access

2010 ◽  
Vol 59 (3) ◽  
pp. 1563-1567 ◽  
Author(s):  
Rong Zhang ◽  
Lei Xu ◽  
Sheng Chen ◽  
L. Hanzo
Keyword(s):  
Multiple Access ◽  
Exit Chart ◽  
Multiuser Detector

Robust MVDR Estimation via Polynomial Rooting for MC-CDMA Carrier Frequency Offset

2013 ◽  
Vol 284-287 ◽  
pp. 2687-2693
Author(s):  
Ing Jiunn Su ◽  
Chiao Chan Huang
Keyword(s):  
Carrier Frequency ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Carrier Frequency Offset ◽  
Low Complexity ◽  
Frequency Offset ◽  
High Accuracy ◽  
Cdma Systems ◽  
Code Division Multiple ◽  
Polynomial Rooting

In this letter, we present a blind carrier frequency offset (CFO) estimator by exploiting the polynomial rooting technique for multicarrier-code division multiple access (MC-CDMA) systems. Relative high accuracy and low-complexity to the CFO estimation can be achieved by rooting a polynomial. Simulation results are provided for illustrating the effectiveness of the proposed blind polynomial rooting estimator.

scholarly journals Uplink NOMA in Body Area Networks With Simple Node Pairing Strategies

2020 ◽  
Author(s):  
Costas Michaelides ◽  
Foteini-Niovi Pavlidou
Keyword(s):  
Interference Cancellation ◽  
Multiple Access ◽  
Body Area Networks ◽  
Resource Block ◽  
Feasible Direction ◽  
Body Area ◽  
Single Node ◽  
Access Protocol ◽  
First Time ◽  
Crucial Part

In body area networks (BANs), a node placed near the hub has a significant signal strength advantage. This issue, known as near-far problem, indicates that a near node may serve as a relay for a far node. Currently, the established orthogonal multiple access (OMA) requires the allocation of a specific resource block to a single node. In contrast, the emerging non-orthogonal multiple access (NOMA) allows simultaneous transmissions and uses successive interference cancellation (SIC) to recover the signals. For the first time in the literature, we introduce NOMA in BANs, to allow simultaneous transmissions from two nodes at a time, with distinguishable power levels. The crucial part of this technique is the dynamic pairing of the nodes by the hub. First, we review the fundamentals of uplink NOMA and we propose an access protocol in compliance with IEEE 802.15.6-2012, which combines random OMA with scheduled NOMA. Next, we propose three node pairing strategies, namely a random, a correlative and a conditional one, to meet the requirements of several applications. These strategies are evaluated with packet level simulations in OMNeT++. Our results show that the proposed scheme outperforms the basic OMA scheme at high packet rates and provides a feasible direction for novel relay-based applications.

scholarly journals Channel Covariance Matrix Estimation via Dimension Reduction for Hybrid MIMO MmWave Communication Systems

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3368
Author(s):  
Rui Hu ◽  
Jun Tong ◽  
Jiangtao Xi ◽  
Qinghua Guo ◽  
Yanguang Yu
Keyword(s):  
Covariance Matrix ◽  
Communication Systems ◽  
Low Complexity ◽  
Low Rank ◽  
Covariance Matrix Estimation ◽  
Hardware Complexity ◽  
Matrix Estimation ◽  
Planar Arrays ◽  
Rank Matrix ◽  
Low Rank Matrix

Hybrid massive MIMO structures with lower hardware complexity and power consumption have been considered as potential candidates for millimeter wave (mmWave) communications. Channel covariance information can be used for designing transmitter precoders, receiver combiners, channel estimators, etc. However, hybrid structures allow only a lower-dimensional signal to be observed, which adds difficulties for channel covariance matrix estimation. In this paper, we formulate the channel covariance estimation as a structured low-rank matrix sensing problem via Kronecker product expansion and use a low-complexity algorithm to solve this problem. Numerical results with uniform linear arrays (ULA) and uniform squared planar arrays (USPA) are provided to demonstrate the effectiveness of our proposed method.

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