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.

scholarly journals Equal-gain combining with interference mitigation for molecular type hopping assisted molecular shift keying systems

2021 ◽  
Vol 2 (2) ◽  
pp. 157-164
Author(s):  
Weidong Gao ◽  
Terrence Mak ◽  
Lie-Liang Yang
Keyword(s):  
Multiple Access ◽  
Interference Mitigation ◽  
Multiple Access Interference ◽  
Low Complexity ◽  
Practical Implementation ◽  
Molecular Type ◽  
Equal Gain Combining ◽  
Detection Scheme ◽  
Reliable Communications ◽  
Shift Keying

In multiple access molecular diffusive communications, many nano-machines exchange information and fuse data through a common Diffusive Molecular Communication (DMC) channel. Hence, there is Multiple-Access Interference (MAI), which should be sufficiently mitigated so as to achieve reliable communications. In this paper, we propose a novel low-complexity detection scheme, namely Equal-Gain Combining with Interference Mitigation (EGC-IM), for signal detection in the Molecular Type Hopping assisted Molecular Shift Keying (MTH-MoSK) DMC systems. By removing a number of entries from each row of the detection matrix formed during detection, the EGC-IM scheme shows its potential to significantly mitigate MAI and hence, outperform the conventional EGC scheme. Furthermore, the EGC-IM scheme has lower complexity than the conventional EGC scheme and therefore, it is beneficial for practical implementation.

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.

Next Generation Wireless Multiple Access Technology OFDMA and SC - FDMA Performance Analysis

2013 ◽  
Vol 336-338 ◽  
pp. 1670-1675
Author(s):  
Lin Wan
Keyword(s):  
Multiple Access ◽  
System Capacity ◽  
Frequency Division ◽  
Theoretical Derivation ◽  
Access Technology ◽  
Single Carrier ◽  
Access Scheme ◽  
Basic Performance ◽  
Better Than

orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC - FDMA) are the two kinds of 4 g wireless multiple access scheme. In the long term evolution (LTE) downlink link access scheme based on OFDMA, at the same time, the uplink access scheme based on SC - FDMA. In this article, we deduced the OFDMA and SC - FDMA basic performance difference, and then demonstrates the comprehensive performance comparisons between them. Theoretical derivation results show that the system capacity is better than that of SC - FDMA OFDMA. Then, we use the numerical simulation results confirm the conclusion. Keywords: OFDMA SC - FDMA basic capacity of the uplink transmission

scholarly journals A Hybrid Multiuser Detector Based on MMSE and AFSA for TDRS System Forward Link

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhendong Yin ◽  
Xu Jiang ◽  
Zhilu Wu ◽  
Xiaohui Liu
Keyword(s):  
Global Convergence ◽  
Multiuser Detection ◽  
Minimum Mean Square Error ◽  
Low Complexity ◽  
System Capacity ◽  
Forward Link ◽  
Artificial Fish Swarm Algorithm ◽  
Multiuser Detector ◽  
Error Ratio ◽  
Bit Error Ratio

This study mainly focuses on multiuser detection in tracking and data relay satellite (TDRS) system forward link. Minimum mean square error (MMSE) is a low complexity multiuser detection method, but MMSE detector cannot achieve satisfactory bit error ratio and near-far resistance, whereas artificial fish swarm algorithm (AFSA) is expert in optimization and it can realize the global convergence efficiently. Therefore, a hybrid multiuser detector based on MMSE and AFSA (MMSE-AFSA) is proposed in this paper. The result of MMSE and its modified formations are used as the initial values of artificial fishes to accelerate the speed of global convergence and reduce the iteration times for AFSA. The simulation results show that the bit error ratio and near-far resistance performances of the proposed detector are much better, compared with MF, DEC, and MMSE, and are quite close to OMD. Furthermore, the proposed MMSE-AFSA detector also has a large system capacity.

scholarly journals Carrier Frequency Offsets Problem in DCT-SC-FDMA System: Investigation and Compensation

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Faisal S. Al-kamali ◽  
Moawad I. Dessouky ◽  
Bassiouny M. Sallam ◽  
Farid Shawki ◽  
Fathi E. Abd El-Samie
Keyword(s):  
Carrier Frequency ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Minimum Mean Square Error ◽  
Multiple Access Interference ◽  
Low Complexity ◽  
Estimation Errors ◽  
Carrier Frequency Offsets ◽  
Frequency Offsets ◽  
The Impact

The Single-Carrier Frequency Division Multiple Access (SC-FDMA) system is a well-known system, which has recently become a preferred choice for uplink channels. In this system, the Carrier Frequency Offsets (CFOs) disrupt the orthogonality between subcarriers and give rise to Intercarrier Interference (ICI), and Multiple Access Interference (MAI) among users. In this paper, the impact of the CFOs on the performance of the Discrete Cosine Transform (DCT) SC-FDMA (DCT-SC-FDMA) system is investigated. Then, a new low-complexity joint equalization and CFOs compensation scheme is proposed to cancel the interference in frequency domain. The Minimum Mean Square Error (MMSE) equalizer is utilized in the proposed scheme. A hybrid scheme comprising MMSE equalization, CFOs compensation, and Parallel Interference Cancellation (PIC) is also suggested and investigated for further enhancement of the performance of the DCT-SC-FDMA system with interleaved subcarriers assignment. For simplicity, this scheme will be referred to as the MMSE+PIC scheme. From the obtained simulation results, it is found that the proposed schemes are able to enhance the system performance, even in the presence of the estimation errors.

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