OFDM-Based MIMO Systems

Asplund, Henrik; Astély, David; Butovitsch, Peter von; Chapman, Thomas; Frenne, Mattias; Ghasemzadeh, Farshid; Hagström, Måns; Hogan, Billy; Jöngren, George; Karlsson, Jonas; Kronestedt, Fredric; Larsson, Elisabeth

doi:10.1016/b978-0-12-820046-9.00005-8

Cited by 3 publications

(5 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The LAS detectors with proposed hybrid schemes show better immunity against the spatial correlation variation up to

ρ = 0.25

. The variation of ψ will not have any significant effect on BER performance as we are not considering any radiation pattern for the receive antennas 39 …”

Section: Simulation Resultsmentioning

confidence: 99%

“…The variation of ψ will not have any significant effect on BER performance as we are not considering any radiation pattern for the receive antennas. 39 Figure 11 considers two cases of BER performance for 32 Â 128, 64-QAM MIMO system with imperfect CSI available at the receiver. The number of iterations for MMSE detectors set to four, phase ψ ¼ 60 ∘ , and ω ¼ 24 is considered for simulation.…”

Section: Performance In Correlated Channel and Imperfect Csimentioning

confidence: 99%

See 1 more Smart Citation

Likelihood ascent search‐aided low complexity improved performance massive MIMO detection in perfect and imperfect channel state information

Chakraborty

Sinha²,

Mitra

2022

Int J Communication

View full text Add to dashboard Cite

Summary Massive multiple‐input multiple‐output (MIMO) systems improve spectral efficiency and link reliability. Linear minimum mean‐squared error (MMSE) detectors can achieve optimal performance in massive MIMO detection but require large dimension matrix inversion, which is computationally intensive. Therefore, low complexity iterative detection schemes are proposed in the literature as an alternative to the exact MMSE method. However, the performance of these schemes is greatly influenced by the choice of the initial solution. Therefore, to improve the detection performance in this paper, we proposed three hybrid detection schemes, which are Newton–Schultz–Richardson (NS‐RI), Newton–Schultz–Chebyshev (NS‐Cheby), and Newton–Schultz–Gauss–Seidel (NS‐GS). The proposed hybrid schemes show significant performance improvement and a higher convergence rate compared to their original counterpart. The performance of the proposed detectors is further improved by the likelihood ascent search (LAS) stage, which corrects the detected symbols obtained from iterative MMSE methods through a neighborhood search. However, the complexity of the LAS algorithm primarily depends on the initialization step. In this work, we introduce an efficient Gram matrix computation in the real domain. Additionally, we have applied a band approximation of the Gram matrix for the LAS initialization, which reduces the order of computational complexity of the Gram matrix from Ofalse(NT2NRfalse) to O(ωNTNR) where ω < <2NT.

show abstract

“…The LAS detectors with proposed hybrid schemes show better immunity against the spatial correlation variation up to

ρ = 0.25

. The variation of ψ will not have any significant effect on BER performance as we are not considering any radiation pattern for the receive antennas 39 …”

Section: Simulation Resultsmentioning

confidence: 99%

Section: Performance In Correlated Channel and Imperfect Csimentioning

confidence: 99%

Likelihood ascent search‐aided low complexity improved performance massive MIMO detection in perfect and imperfect channel state information

Chakraborty

Sinha²,

Mitra

2022

Int J Communication

View full text Add to dashboard Cite

show abstract

“…Because of this, OFDM is usually robust in frequencyselective environments and has decisive spectral efficiency. At the same time, its PAPR is high as well due to the use of the inverse fast Fourier transform (IFFT) operations; linear combinations of many QAM symbols involved in the IFFT operation can create large and highly varying peaks in the output signal [56]. The block diagram in Fig.…”

Section: Ofdmmentioning

confidence: 99%

“…For OFDM, OTFS, and DFT-s-OFDM, the calculation process is different; due to the numerous linear combinations of symbols in the IFFT operation, the number of possible outcomes is very large, so we must consider an upper bound. For OFDM, the maximum PAPR is PAPR dB = 10 log 10 (N ), (10) which is a function of the number of subcarriers, N [56].…”

Section: A Papr Calculationmentioning

confidence: 99%

“…OFDM and OTFS we see a large penalty due to their use of the IFFT/FFT and ISFFT/SFFT. DFT-s-OFDM maintains a reduced penalty in comparison due to the DFT pre-processing block [56]; however, a larger penalty still exists since the DFT block size must be less than the number of subcarriers, so the effects of the FFT will not be entirely canceled out.…”

Section: B Proposed Papr Penaltymentioning

confidence: 99%

See 1 more Smart Citation

Modulations for Terahertz Band Communications: Joint Analysis of Phase Noise Impact and PAPR Effects

Parisi,

Badran,

Sen

et al. 2024

IEEE Open J. Commun. Soc.

View full text Add to dashboard Cite

The choice of modulation techniques for next-generation communications in the sub-terahertz and terahertz bands remains largely unresolved. A variety of traditional and new schemes show promise, but the question remains open on the illustrative comparison process for realistic terahertz systems. While there are some preliminary studies in this area, we emphasize that the peculiarities of terahertz hardware necessitate a scheme that (i) is resistant to system-wide phase noise (PN) and (ii) has a low peak-to-average power ratio (PAPR). Therefore, in this article, we present a comprehensive methodology to carefully model and jointly study the impacts of PN and PAPR on the performance of candidate modulations for terahertz links. We first deliver a mathematical model for sub-terahertz/terahertz phase noise impairments at 130 GHz, 225 GHz, and 1.02 THz based on measurements from actual terahertz hardware. We then introduce the PAPR penalty -an approach for fair comparison of bit error rate (BER) and spectral efficiency (SE) of modulation schemes with different PAPRs. We finally combine these two effects to comprehensively study the characteristics of single and multi-carrier modulation schemes for terahertz communications. Our study reveals that analyzing PAPR and PN jointly is paramount: accounting for only one leads to major deviations in the numerical results and misleading conclusions on best modulation choice(s). The delivered framework and evaluation should facilitate further studies, leading to a well-motivated selection of the most suitable modulation scheme(s) for prospective sub-terahertz and terahertz radio systems.

show abstract

Technique for Large-Scale Antenna Beamforming Based on Neural Network

Xie

Guo

JianZhou

2022

Wireless Communications and Mobile Computing

View full text Add to dashboard Cite

The commercialization of the fifth-generation technology and the rapid development of Internet of Things technology have made mobile communication networks increasingly complex. Simultaneously, the massive terminal connections have caused serious interference between networks. Large-scale array antennas have become a hot topic of recent studies to improve the wireless transmission characteristics and spectrum resource utilization efficiency. This study was aimed at exploring using large-scale array antennas combined with neural networks in ultradense cells to improve the wireless signal transmission quality. The simulation results showed that the scheme realized not only the wireless signal transmission with a neural network but also the effective recovery of the source signal. Similarly, the application of this scheme effectively reduced the power consumption during signal transmission, the delay, and the interference.

show abstract

OFDM-Based MIMO Systems

Cited by 3 publications

References 2 publications

Likelihood ascent search‐aided low complexity improved performance massive MIMO detection in perfect and imperfect channel state information

Likelihood ascent search‐aided low complexity improved performance massive MIMO detection in perfect and imperfect channel state information

Modulations for Terahertz Band Communications: Joint Analysis of Phase Noise Impact and PAPR Effects

Technique for Large-Scale Antenna Beamforming Based on Neural Network

Contact Info

Product

Resources

About