Single Carrier Frequency Division Multiple Access Research Articles

Progressive Pattern Interleaver with Multi-Carrier Modulation Schemes and Iterative Multi-User Detection in IoT 6G Environments with Multipath Channels.

Sixth-generation (6G) wireless networks demand a more efficient implementation of non-orthogonal multiple access (NOMA) schemes for severe multipath fading environments to serve multiple users. Using non-orthogonal multiple access (NOMA) schemes in IoT 6G networks is a promising solution to allow multiple users to share the same spectral and temporal resource, increasing spectral efficiency and improving the network's capacity. In this work, we have evaluated the performance of a novel progressive pattern interleaver (PPI) employed to distinguish the users in interleaved division multiple access (IDMA) schemes, suggested by 3GPP guidelines as a NOMA scheme, with two multi-carrier modulation schemes known as single-carrier frequency-division multiple access (SC-FDMA) and orthogonal frequency-division multiplexing (OFDM), resulting in SC-FDMA-IDMA and OFDM-IDMA schemes. Both schemes are multi-carrier schemes with orthogonal sub-carriers to deal against inter-symbol interference (ISI) and orthogonal interleavers for the simultaneous access of multiple users. It has been suggested through simulation outcomes that PPI performance is adequate with SC-FDMA-IDMA and OFDM-IDMA schemes in terms of bit error rate (BER) under multipath channel conditions. Moreover, regarding bandwidth requirement and the implementation complexity of the transmitted interleaver structure, PPI is superior to the conventional random interleaver (RI).

Deep Learning-Based SC-FDMA Channel Equalization

It is very challenging to design an effective wireless communication system. That’s because of numerous factors affecting the performance of a typical wireless communication system, such as nonlinear channel distortions and impairments. single carrier frequency division multiple access (SC-FDMA) is a multiple access scheme that is an important part of the long-term evolution (LTE) standard for uplink transmission. An advanced mobile radio system’s multiple access schemes should indeed meet stringent requirements, such as a low bit error rate (BER). In this article, we investigate the equalization problem for nonlinear channel distortions and impairments using deep neural networks (NN). We introduce a novel combined deep neural network channel equalization and symbol detection scheme based on a deep learning (DL) recurrent feedback (RF) long short-term memory (LSTM) neural network to achieve blind equalization and decoding for SC-FDMA systems without knowing the channel state information (CSI). To train the model efficiently, the training data is gathered by simulation, with channel effects and noise treated as a complete black box. CSI and constellation demapping are learned by a deep neural network (DNN) model. Then, the frequency-domain sequences that have been corrupted are implicitly equalized to get the broadcasted signal back. Our specified SC-FDMA system, which uses a quadrature phase-shift keying (QPSK) modulation method and the suggested Deep Learning-based model channel equalizer, performs better than the existing equalizers by an average of 1 to 4 dB at moderate signal-to-noise (SNR) ratios, according to simulation data. A complexity comparison between the proposed and the conventional equalizers was conducted in terms of training time, execution time, and number of operations. On combined channel equalization and symbol detection, the suggested system delivers state-of-the-art performance.

Encrypted images in a V‐BLAST assisted SC‐FDMA wireless communication system

AbstractThe internet of things (IoT) relies on fifth generation (5G) networks as the foundation for interconnecting devices. Wireless networks are an essential component of 5G‐IoT technology, as they provide the means to interconnect devices and transmit data wirelessly. The performance of the wireless network, including its capacity, integrity, bandwidth, and latency, is critical in ensuring the reliable and secure transmission of data in 5G‐IoT. 5G is being developed with the goal of delivering exceptionally high capacity, solid integrity, high bandwidth, and low latency. With the development and innovation of new approaches for 5G‐IoT, new significant security and privacy concerns are certain to arise. As a result, secure data transmission mechanisms will be required as the foundation for 5G‐IoT technologies in order to solve these emerging difficulties. Deoxyribonucleic acid (DNA) cryptograms encrypt data by utilizing it as a carrier and biological technology. On an 8 by 8 multiantenna single carrier frequency division multiple access (SC‐FDMA) wireless system, we evaluate and compare the performance of DNA sine map‐based encrypted images using three different modulation algorithms: 16‐QAM, 16‐PSK, and 16‐DPSK. We also determine the bit error rate (BER) value for different signal to noise ratio (SNR) by analyzing the decrypted image's modulation performance. The methods minimum mean square error (MMSE), minimum mean error square successive interference cancelation (MMSE‐SIC), and zero‐forcing (ZF) are utilized for signal detection. Simulations in MATLAB reveal that the system is very effective and reliable when tested with MMSE‐SIC signal detection, 16‐QAM modulation, and low‐density parity check (LDPC) channel coding.

On companding techniques for PAPR reduction in DCT SC-FDMA system in the presence of CFOs

In the single carrier frequency division multiple access (SC-FDMA) system, the use of discrete cosine transform (DCT) instead of discrete Fourier transform (DFT) has shown improved bit error rate (BER) performance. Nevertheless, peak-to-average power ratio (PAPR) in the DCT-based SC-FDMA system is higher than that in the DFT-based system. This paper investigates the performance of various companding schemes to reduce PAPR in DCT-based SC-FDMA systems by considering carrier frequency offsets (CFOs). Simulation results, considering parameters like BER, PAPR, and power spectral density (PSD), are provided to find the best companding technique. Furthermore, the results have been validated in a real-time indoor channel using a wireless open-access research platform (WARP) hardware.

Low‐complexity joint equalization and CFO compensation in uplink SC‐FDMA NOMA system under different power allocation strategies

AbstractIn current wireless systems, the claim for rapid data services has become unavoidable in broadband communication. Single carrier frequency division multiple access (SC‐FDMA) has remained a multiple access (MA) technique with low peak‐to‐average power ratio (PAPR) in 4G systems. Non‐orthogonal multiple access (NOMA) is a complimentary MA technique in the fifth generation (5G) new radio with the capability of using similar frequency elements for multiuser communication within a single cellular system. In SC‐FDMA NOMA systems the carrier frequency offsets (CFO) destroy the orthogonal behavior in multiple carriers during transmission leading to inter‐carrier interference (ICI) and multiple access interference (MAI). Furthermore, the power allocated for each user in the NOMA cluster exhibits a noticeable part in enhancing the performance of the system. In this article, we propose a joint low‐complexity linear regularized zero forcing (JLC‐LRZF) for SC‐FDMA NOMA system and investigate its performance using discrete Fourier transform (DFT) and discrete cosine transform (DCT). The proposed JLC‐LRZF equalization algorithm is capable of performing equalization and CFO compensation with low‐complexity with banded‐matrix approximation (BMA). Additionally, we investigate the effectiveness of SC‐FDMA NOMA system in achieving improved performance with different values of CFO and power allocation policies in uniform random multipath channels.

COMPARISON OF PERFORMANCES BETWEEN SC-FDMA AND OFDMA SYSTEMS UNDER DIFFERENT SUBCARRIER MAPPING SCHEMES

To improve the uplink performance of wireless network for long term evolution (LTE) single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA) are used. Two major concerns of these SC-FDMA and OFDMA are high peak-to-average power ratio (PAPR) and efficient subcarrier mapping scheme. This paper presents a performance comparison of SC-FDMA and OFDMA under different subcarrier mapping schemes which includes localized FDMA (LFDMA), distributed FDMA (DFDMA) and interleaved FDMA (IFDMA). Quadrature amplitude modulation (QAM) with different constellation sizes is used. The symbol error rate (SER) in SC-FDMA is minimized using appropriate mapping scheme. The PAPR is less in SC-FDMA compared to OFDMA. SC-FDMA with IFDMA shows better performance for the PAPR reduction compared to the OFDMA. Compared to OFDMA, using SC-FDMA with 8-QAM and IFDMA, PAPR is reduced by 78%, using SC-FDMA with 16-QAM and IFDMA, PAPR is reduced by 80%, using SC-FDMA with 64-QAM and IFDMA, PAPR is reduced by 68%.

Equalization Techniques for SC-FDMA Systems Under Radio Imbalances at Both Transmitter and Receiver

Orthogonal frequency division multiple access (OFDMA) is a multi-carrier, multiple access (MA) technique, which is widely adopted in contemporary wireless standards. Single carrier-frequency division multiple access (SC-FDMA) is a modified version of OFDMA which employs single carrier transmission by pre-coding the data symbols using discrete Fourier transform (DFT). However, these systems are highly vulnerable to the adverse effects arising in the channel, carrier frequency offset (CFO) and in-phase/quadrature phase (I/Q) imbalances. In the uplink communication scenario, the signal received at base station is the superposition of signals from all the active users. Even though the adverse effects caused by the communication channel and CFOs are addressed in the related literature extensively, the effect of I/Q-imbalances at the transmitter and the receiver is rarely considered. The effect of I/Q-imbalances will make the equalization process at the base station more complex. It is because the overall effective channel with radio impairments must be included in the system modelling. Hence the receiver processing should contain the equalization for effect of the channel, CFOs and I/Q imbalances. In this paper, we propose a novel technique based on the oblique projection (OP) technique for equalizing the channel, radio imbalances and synchronization errors caused by both transmitter (TX) and receiver (RX) for OFDMA/SC-FDMA uplink systems. We also propose an equalization technique with reduced computational complexity to overcome the adverse effects caused by I/Q imbalances and CFOs. The results of the simulation studies illustrate that the proposed techniques can compensate all the above-mentioned effects and they offer very good performance under both TX and RX I/Q imbalances.

A Powerful Joint Modulation and STBC Identification Algorithm for Multiuser Uplink SC-FDMA Transmissions

Owing to the rapid development and broad adoption of multiple antenna communication systems over the past few years, space-time block coding (STBC) identification has emerged as a crucial responsibility for smart radios. The majority of previous analysis of STBC identification assumed that the utilized modulation schemes for single-user and uncoded broadcasts were known. This paper investigates the challenge of joint STBC and modulation identification for uplink transmissions with numerous users in single-carrier frequency division multiple access (SC-FDMA) systems using coded transmissions. Multi-user channel estimation brings us one step closer to implementing the proposed design in real-world systems. We additionally employ the channel decoder’s deliverables, which are common in many real-world systems, to enhance the identifying and estimating procedures. Mathematical findings prove that a recursive approach can be utilized to tackle the maximum likelihood (ML) problem of simultaneous STBC and modulation identification with channel estimation. Distinguishing the superimposed signals that originate at the base-station (BS) is accomplished with the use of the space-alternating generalized expectation-maximization (SAGE) algorithm. After that, an expectation-maximization (EM) engine is deployed to make the necessary adjustments to the parameters being considered for each user. The success of the above-mentioned architecture for usage in practical applications is demonstrated by the simulation results obtained under various conditions.

Performance Analysis of Zero-Padded Sequences for Joint Communications and Sensing

Self-interference (SI) is a known but critical issue at the receiver side of a monostatic radar in joint communications and sensing (JCAS) systems, and this is particularly true for high spectral-efficient waveforms. Full-duplex transceivers are usually assumed in the literature, but it is arguable if they can be taken for granted in many devices. We propose a different approach, by eliminating the SI using zero-padded (ZP) orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-division multiple access (SC-FDMA), instead of the more widespread cyclic-prefix (CP)-OFDM. ZP-sequences do not need full-duplex for the monostatic radar operation, as there is no SI between the transmit and receive antennas during the guard interval (GI), which can be used for radar detection. We derive the required radar receiver processing for ZP-sequences and CP-OFDM in time and frequency domains, respectively, to show that when the SI in JCAS is high, ZP-sequences can be beneficial, depending on the target range. Furthermore, we prove analytically that the low peak-to-average power ratio (PAPR) of ZP-SC-FDMA, when compared to ZP-OFDM, is beneficial in time-domain radar processing. This is demonstrated also by means of numerical simulation with ROC curves, for all the candidate waveforms in both coherent and incoherent receiver processing.

Self-Adaptive Game Theoretic Approaches for Resource Allocation in SC-FDMA Based Heterogeneous Networks

We investigate the resource blocks (RBs) allocation problem in the Single-Carrier Frequency Division Multiple Access (SC-FDMA) based heterogeneous uplink networks from a game-theoretical viewpoint. First, a general network model that considers the co-tier, cross-tier, and inter-cell interference caused by the co-channel deployment is presented. Then, we design an effective throughput-optimizing utility function and prove it an exact potential game. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> -logit is a learning algorithm which commonly used to achieve the optimal solution in potential game and is very sensitive to the changes of the network structures, making it hard in practice. To obtain the optimal solution under the different network structures stably, we propose a Self-adaptive logit algorithm, which can achieve the optimal solution automatically and is a variant of the well-established <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> -logit learning algorithm. Additionally, to speed up the convergence, we propose the corresponding suboptimal algorithm based on the better response principle. Simulation results show that the proposed Self-adaptive logit algorithm is throughput optimal and network structure adaptive, outperforming the existing Binary-logit, Max-logit, and Round Robin algorithm. Moreover, the proposed suboptimal algorithm is near-optimal throughput achieved and converges efficiently. In addition, we also study the impact of the initial point selection on our proposed two alogithms.

Low complexity ordered successive interference cancelation detection algorithm for uplink MIMO SC‐FDMA system

AbstractIn mobile communication, the most exploratory technology of fifth generation is massive multiple input multiple output (MIMO). The minimum mean square error and zero forcing based linear detectors are used in multiuser detection for MIMO single‐carrier frequency division multiple access (SC‐FDMA). When the received signal is detected and regularization sequence is joined in the equalization of spectral null amplification, these schemes experience an error performance and the signal detection assesses an inversion of a matrix computation that grows into complexity. Ordered successive interference cancelation (OSIC) detection is considered for MIMO SC‐FDMA, which uses a posteriori information to eradicate these problems in a realistic environment. To cancel the interference, sorting is preferred based on signal‐to‐noise ratio and log‐likelihood ratio. The distinctiveness of the methodology is to predict the symbol with the lowest error probability. The proposed work is compared with the existing methods, and simulation results prove that the defined algorithm outperforms conventional detection methods and accomplishes better performance with lower complication.

Performance Improvement for the Single Carrier in FBMC Systems by PAPR Reduction

The benefits of Filter Bank Multicarrier (FBMC) make it an attractive waveform instead of orthogonal frequency division multiplexing (OFDM). However, a high peak-to-average power ratio (PAPR) is a significant drawback in FBMC. Exploiting a single carrier effect is considered an effective technique to reduce PAPR in FBMC systems with a small amount of additional complexity. Nevertheless, the PAPR reduction amount is different from the single carrier effect in the single carrier frequency division multiple access (SC-FDMA). This is because of the overlapping structure of the in-phase and quadrature (IQ) between offset quadrature amplitude modulation (OQAM) FBMC symbols. So, we introduce an algorithm, based on signal distortion techniques, to improve the performance of the single carrier effect techniques in the PAPR reduction for the FBMC systems. Simulation results depict that the single carrier effect techniques with the proposed algorithm achieve an extra amount of PAPR reduction compared to the same techniques without using the proposed algorithm. In addition, the simulation results show that the proposed algorithm maximizes the PAPR reduction amount without affecting the complexity.

Active device detection and performance analysis of massive non-orthogonal transmissions in cellular Internet of Things

This paper investigates multiple access schemes for uplink and downlink transmissions in cellular networks with massive Internet of Things (IoT) devices. Recall that single-carrier frequency division multiple access and orthogonal frequency division multiple access, which are orthogonal multiple access (OMA) schemes, have been conventionally adopted for uplink and downlink transmissions in narrow-band IoT, respectively. Unlike these OMA schemes, we propose two non-orthogonal multiple access (NOMA) schemes for cellular IoT with short-packet transmissions. Especially, a generalized expectation consistent signal recovery-based algorithm is proposed to estimate active devices, channel state information and data in uplink transmission, where all of the active devices are allowed to transmit their pilots and data through the same resource block without authorization. On the other hand, the active devices estimated during uplink transmission are grouped for downlink transmission with a trade-off between performance and detection complexity. Additionally, the data error rates are analysed for both uplink and downlink transmissions with low-resolution analog-to-digital converters (ADCs), where the effects of critical parameters such as the estimation error, ADC bits, packet length, and message bits are revealed. Both simulation and analytical results are provided to demonstrate the excellent performance of the proposed NOMA schemes and algorithms, especially for active device, channel, and data estimations. More importantly, the obtained results show that the data error rate performance of downlink NOMA is superior to that of OMA when the message bits of devices in one group are selected following the proposed strategy.

End-To-End Performance of an Uplink NB-IoT Transmission Relayed on a Low-Altitude UAV Platform with Non-Orthogonal Single-Carrier FDMA in the Optical Wireless Backhaul Link

A current trend in the evolution of mobile communication networks consists in integrating Non-Terrestrial Networks (NTN) with the Terrestrial ones. One option to implement the NTN part of this hybrid architecture using Unmanned Aerial Vehicles (UAV) that relay the uplink radio signals through optical wireless backhaul links. A good choice for the radio uplink waveform is conventional SC-FDMA, which mitigates the PAPR and enables a longer battery lifetime at the transmitter side. For the optical backhaul link, which is based on low-cost Visible Light Communication (VLC) technology, a non-orthogonal implementation of SC-FDMA is proposed. By doing so, it is possible to improve the end-to-end throughput by reducing the communication bandwidth (to make it fit the LED frequency response), mitigate the effect of light reflections, and increase the energy efficiency in the backhaul link. Since VLC relies on non-coherent IM/DD, the non-orthogonal SC-FDMA waveform must rotate the phase of the IDFT subcarriers, in order to obtain real-valued signal samples at the output. Two strategies for relaying the data in the UAV node are evaluated, namely: Detect-and-Forward and Decode-and-Forward. The first one recovers the modulation part (i.e. partial regeneration), whereas the second one regenerates the transmitted message up to the bit level (i.e., total regeneration). This paper studies the combination of relaying strategy and NB-IoT Modulation and Coding Scheme (MCS) that maximizes the end-to-end throughput at different UAV altitudes.

End-to-end performance of an uplink NB-IoT transmission relayed on a low-altitude UAV platform with Non-Orthogonal Single-Carrier FDMA in the optical wireless backhaul link

End-to-end performance of an uplink NB-IoT transmission relayed on a low-altitude UAV platform with Non-Orthogonal Single-Carrier FDMA in the optical wireless backhaul link

LTE Cellular Networks Packet Scheduling Algorithms in Downlink and Uplink Transmission: A Survey

This survey paper provides a detailed explanation of Long Term Evolution (LTE) cellular network’s packet scheduling algorithms in both downlink and uplink directions. It starts by explaining the difference between Orthogonal Frequency Division Multiple Access (OFDMA) that is used in downlink transmission, and Single Carrier – Frequency Division Multiple Access (SC-FDMA) is used in uplink. Then, it explains the difference between the LTE scheduling process in the donwlink and uplink through explaining the interaction between users and the scheduler. Then, it explains the most commonly used downlink and uplink scheduling algorithms through analyzing their formulas, characteristics, most suitable conditions for them to work in, and the main differences among them. This explanation covers the Max Carrier-toInterference (C/I), Round Robin (RR), Proportional Fair (PF), Earliest Deadline First (EDF), Modified EDF-PF, Modified-Largest Weighted Delay First (M-LWDF), Exponential Proportional Fairness (EXPPF), Token Queues Mechanism, Packet Loss Ratio (PLR), Quality Guaranteed (QG), Opportunistic Packet Loss Fair (OPLF), Low Complexity (LC), LC-Delay, PF-Delay, Maximum Throughput (MT), First Maximum Expansion (FME), and Adaptive Resource Allocation Based Packet Scheduling (ARABPS). Lastly, it provides some concluding remarks.

Complementary Coded CDMA With Multi-Layer Quadrature Modulation

In an orthogonal frequency division multiplexing (OFDM) system, cyclic prefix (CP) has to be added to eliminate multipath-induced inter-symbol interference (ISI) with a severely sacrificed bandwidth efficiency. Peak-to-average ratio (PAPR) may impair its performance further if a large number of carriers are used. On the other hand, traditional multi-carrier modulation suffers a prohibitive complexity, which can not be implemented with colorred current available silicon technologies. This work proposes a cost-effective way to implement multi-carrier modulation, namely multi-layer quadrature (MLQ) modulation, which requires only two oscillators. As an application example, we apply MLQ modulation to a complementary coded code division multiple access (MLQ-CC-CDMA) system, whose multi-carrier transmission is based on MLQ modulation to mitigate ISI and multi-user interference (MUI) with ideal auto- and cross-correlations of complementary codes. Compared to a frequency domain (FD) CC-CDMA system, MLQ-CC-CDMA has a lower RF complexity. Compared to OFDM direct sequence (DS) CDMA and single carrier frequency division multiple access (SC-FDMA) CDMA schemes, MLQ-CC-CDMA achieves a higher spectrum efficiency (SE) and a lower bit error rate with Rake and minimum mean square error (MMSE) detection due to its powerful multipath and multi-carrier diversity gains.

Efficient Transmission of 2D Chaotic Maps Encrypted Images with DWT-Based SC-FDMA LTE System

The single-carrier frequency division multiple access (SC-FDMA) is a promising technique that has been adopted as an uplink transmission scheme in the long-term evolution (LTE) cellular system. This is attributed to its advantages such as the low peak-to-average power ratio (PAPR) and the utilization of frequency-domain equalizers to resolve the problem of inter-symbol interference (ISI). In this paper, a Discrete Wavelet Transform (DWT) based SC-FDMA system is proposed for the effective transmission of encrypted images. The 2D Chaotic baker map encryption algorithm has been used to encrypt images to enhance their security during transmission via SC-FDMA- based systems. The performance of the process of encrypted image transmission using the 2D Chaotic baker map algorithm with wavelet transform-based SC-FDMA (DWT SC-FDMA) system is evaluated in terms of different performance metrics, with comparison to Discrete Fourier Transform SC-FDMA (DFT SC-FDMA) and, Discrete Cosine Transform SC-FDMA (DCT SC-FDMA) systems. The viability of the proposed scheme was tested with different wireless channel models and different subcarriers mapping schemes. Experimental results show that the proposed method of the encrypted image transmission via the DWT SC-FDMA system provides a remarkable performance gain compared to the other versions of the SC-FDMA system in terms of the PSNR, and the BER metrics in the wireless channel models. It also demonstrates the effectiveness of the proposed scheme and adds a degree of encryption to the transmitted images through the wireless channels.

STBC Identification for Multi-User Uplink SC-FDMA Asynchronous Transmissions Exploiting Iterative Soft Information Feedback of Error Correcting Codes

With the advancement and widespread implementation of multiple-input multiple-output (MIMO) wireless communication systems over the last decade, space-time block coding (STBC) identification has become a critical task for intelligent radios. Previous examinations of STBC identification were focused on single-user transmissions over single-carrier and multi-carrier systems in combination with uncoded broadcasts. Practical systems, on the other hand, contain many users and employ error-correcting codes. For the first time in literature, this work explores the problem of STBC identification for multi-user uplink transmissions in single-carrier frequency division multiple access (SC-FDMA) systems. We take another step closer to real systems by addressing asynchronous transmissions and by conducting multi-user channel estimation. We also exploit the outputs of the channel decoder, which is usually used in many practical systems, to improve the identification and estimation processes. The mathematical analysis demonstrates that the maximum-likelihood (ML) solution of STBC identification, channel estimation, and synchronization can be executed by an iterative approach. The space-alternating generalized expectation-maximization (SAGE) algorithm is used to separate the overlaid signals arriving at the base-station (BS). The parameters under consideration for each user are then updated using an expectation-maximization (EM) processor. Simulation results show that the proposed architecture outperforms other identification methods published in the literature while maintaining a reasonable level of processing time.

Design and Testbed Implementation of Multiuser CFOs Estimation for MIMO SC-FDMA System

In this paper, we propose and implement blind multiuser carrier frequency offsets (CFOs) estimation for multi-input multi-output (MIMO) single carrier frequency division multiple access (SC-FDMA) uplink system using orthogonal propagator method (OPM) over a noisy frequency-selective channel. The performance of typical OPM is limited at low signal-to-noise ratio (SNR) due to its noise-free signal model. The additive white Gaussian noise mainly impacts the diagonal elements of the data covariance matrix (DCM) of the received signal. First, the proposed fractional CFOs estimator minimizes the noise effect by reconstructing the denoised diagonal elements of the DCM for the received signal through cubic Hermite interpolation. Therefore, we use modified OPM to estimate multiple CFOs for MIMO SC-FDMA systems. Second, we have used an iterative method based on the first-order Taylor series approximation of the CFO vector to avoid peak ambiguity and reduce the number of iterations required in the grid search. The mean square error of the proposed CFO estimator considerably improves compared with the existing methods at a low SNR regime. The bit error rate performance of the proposed method for MIMO SC-FDMA is also compared with the existing methods. Finally, the proposed estimator is validated by implementing it on radio frequency hardware testbed over an indoor propagation environment.