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This paper aims to present an approach of utilizing multiple-input multiple-output (MIMO) radar concept to enhance pedestrian classification in automotive sensors. In a practical environment, radar signals reflected from pedestrians and slow-moving vehicles are similar in terms of reflecting angle and Doppler returns, inducing difficulty for target discrimination. An efficient discrimination between the two targets depends on the ability of the sensor to extract unique characteristics from each target, for example, by exploiting Doppler signatures. This study describes the utilization of MIMO radar for Doppler measurement and demonstrates its application to improve pedestrian classification through actual laboratory measurements.

Multiple non-modulated sinusoidal signals are transmitted orthogonally over a MIMO array using time division scheme, illuminating human and non-human targets. The reflected signal entering each of the receiving antenna are combined at the radar receiver prior to Doppler processing. Doppler histogram was formulated based on a series of measurements, and the Doppler spread of the targets was determined from the histograms. Results were compared between MIMO and conventional single antenna systems.

Measurement results indicated that the MIMO configuration provides able to capture more Doppler information compared to conventional single antenna systems, enabling a more precise discrimination between pedestrian and other slow-moving objects on the road.

The study demonstrated the effectiveness of using MIMO configuration in radar-based automotive sensor to enhance the accuracy of Doppler estimation, which is seldom highlighted in literature of MIMO radars. The result also indicated its usefulness in improving target discrimination capability of the radar, through actual measurement.

Multiple-input multiple-output (MIMO) combined with multi-user massive MIMO has been a well-known approach for high spectral efficiency in wideband systems, and it was targeted to detect the MIMO signals. The increasing data rates with multiple antennas and multiple users that share the communication channel simultaneously lead to higher capacity requirements and increased complexity. Thus, different detection algorithms were developed for the Massive MIMO.

This paper focuses on the various literature analyzes on various detection algorithms and techniques for MIMO detectors. Here, it reviews several research papers and exhibits the significance of each detection method.

This paper provides the details of the performance analysis of the MIMO detectors and reveals the best value in the case of each performance measure. Finally, it widens the research issues that can be useful for future researchers to be accomplished in MIMO massive detectors

This paper has presented a detailed review of the detection of massive MIMO on different algorithms and techniques. The survey mainly focuses on different types of channels used in MIMO detections, the number of antennas used in transmitting signals from the source to destination, and vice-versa. The performance measures and the best performance of each of the detectors are described.

This study aims to present dual band reconfigurable MIMO antenna for 5G (sub-6 GHz) and WLAN applications.

To achieve optimum bandwidth, radiation pattern and radiation efficiency, the defected ground structure (DGS) and a rectangular stub connected with the DGS are used. To further cover the sub-6 GHz spectrum (3.4–3.6 GHz) for future 5G communications, a two-element multi-input multi-output (MIMO) antenna configuration is designed by using the single element antenna. The proposed reconfigurable MIMO antenna using a PIN diode is designed on an FR4 substrate with a dielectric constant of 4.4 and a loss tangent of 0.02 and a 35 × 20 × 1.6 mm³ dimension.

The proposed antenna achieved dual operating bands of 3.4–4.1 GHz (5 G sub-6GHz applications) and 4.99–5.16 GHz (WLAN application) in the D = ON state. For D = OFF state, the proposed antenna achieved 3.55–3.65 GHz and 3.66–4.05 GHz frequency bands for 5G (sub-6GHz) applications. In terms of the envelop correlation coefficient, diversity gain, mean effective gain, total active reflection coefficient and isolation between the ports, the proposed antenna’s diversity performance characteristics are investigated and the obtained values are 0.05, 9.9 dB, ±3dB, −4dB, −15dB, respectively.

The fabricated prototype antenna on FR4 substrate has measurable parameters that are in good agreement with the simulated findings. Due to hardware design limitations, there is a minor difference between software and hardware results.

The proposed MIMO antenna is compact and reconfigurable for 5G (sub-6GHz) and WLAN applications, and from the graph, the measurements and simulations have been found to be in close agreement.

This study aims to propose a two-element multi-input-multi-output (MIMO) antenna for cognitive radio MIMO applications to avoid the complexities involved in reconfigurable antennas and improve the spectrum utilization efficiency.

The proposed MIMO antenna system comprises a wideband antenna that operates at 2 GHz–12 GHz for sensing the spectrum and four pairs of antennas for communication, which are single and dual-band antennas. Each pair of antennas meant for communication consists of two similar antennas. Moreover, the antennas meant for communication cover 93% of the bandwidth of the sensing antenna.

The first pair of antennas accessible at ports P2 and P6 and the second pair of antennas accessible at ports P4 and P8, which are dual-band antennas, operate at 3.05 GHz–3.85 GHz, 5.8 GHz–8 GHz and 2.05 GHz–2.55 GHz, 4.7 GHz–6.1 GHz, respectively. While the third pair of antennas accessible at ports P3 and P7 and the fourth pair of antennas accessible at ports P5 and P9 are single-band antennas and operate at 3.85 GHz–4.7 GHz and 8 GHz–11 GHz, respectively. Minimum isolations of 20 dB and 15 dB are attained between every two similar antennas for communication and between the sensing antenna and the antennas meant for communication, respectively. The correctness of the proposed antenna is verified with a fine match between the results obtained from simulations and measurements.

The proposed MIMO antenna possesses salient features, such as polarization diversity and performing a maximum of four communication tasks when all the white spaces are detected.

An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands of multi-input multi-output (MIMO) antenna. These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the impedance bandwidth (IBW) of the MIMO antenna, and its diligent adjustment of it leads to cover the frequency range of Bluetooth and Wireless Local Area Network systems.

A new MIMO antenna is introduced in this paper in conjunction with an enhanced Wilkinson power divider feeding platform.

These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the IBW of the MIMO antenna, and its diligent adjustment leads to covering the frequency range of Bluetooth and WLAN systems.

The proposed MIMO antenna benefits from good isolation between ports for both frequency bands. The proposed MIMO antenna is constructed on FR4 substrate with a volume of 90 × 134 × 1.6 mm3.

This paper aims to design a most demanding low profile and compact ultra-wide band (UWB) antenna system for various wireless applications. The performance (in terms of data rate) of UWB system is improved by using multiple-input-multiple-output (MIMO) technology with it. Owing to the overlap of other existing licensed bands with that of UWB, electromagnetic signals can interfere. So, notched band UWB MIMO antenna system reported here which is highly compact, bandwidth efficient, superior data rate and high inter-element isolation comparatively to other reported designs.

A 49 × 49 × 1.6 mm³ quad-port UWB MIMO antenna with specific bandwidth elimination property is designed. The proposed planar MIMO configuration comprises unique four identical “Cordate-shaped” monopole radiators fed by 2.3-mm thick microstrip-lines. The radiators are located right-angled to each other to enhance inter-element isolation. Further, a different approach of slitted-substrate is applied to minimize the overall size and mutual coupling of the MIMO antenna, as a substitute of decoupling and matching structures. The defected ground structure is used to obtain −10 dB impedance bandwidth in entire UWB band, without compromising with the lower cut-off frequency response. Further, to eliminate the undesired resonant band (WLAN at 5.5 GHz) from UWB, a rounded split ring resonator is introduced in monopole patch.

In the entire operating band of 2.8 to 11 GHz, isolation among elements is more than 24 dB, envelope correlation coefficient less than 0.002, diversity gain greater than 9.99 dB and TARC less than −7 dB are obtained at all 4-ports.

The measured parameters of the fabricated prototype antenna on FR4 substrate are found in good agreement with the simulated results. The small variation in software results and hardware results are observed due to hardware design limitations.

The proposed design may be used for any wireless application following in the range of UWB.

It can be shown from graphs of measured parameters of the fabricated prototype antenna. They found to be in good agreement with the simulated results.

The suggested work examines the latest developments such as the techniques employed for allocation of power, browser techniques, modern analysis and bandwidth efficiency of nonorthogonal multiple accesses (NOMA) in the network of 5G. Furthermore, the proposed work also illustrates the performance of NOMA when it is combined with various techniques of wireless communication namely network coding, multiple-input multiple-output (MIMO), space-time coding, collective communications, as well as many more. In the case of the MIMO system, the proposed research work specifically deals with a less complex recursive linear minimum mean square error (LMMSE) multiuser detector along with NOMA (MIMO-NOMA); here the multiple-antenna base station (BS) and multiple single-antenna users interact with each other instantaneously. Although LMMSE is a linear detector with a low intricacy, it performs poorly in multiuser identification because of the incompatibility between LMMSE identification and multiuser decoding. Thus, to obtain a desirable iterative identification rate, the proposed research work presents matching constraints among the decoders and identifiers of MIMO-NOMA.

To improve the performance in 5G technologies as well as in cellular communication, the NOMA technique is employed and contemplated as one of the best methodologies for accessing radio. The above-stated technique offers several advantages such as enhanced spectrum performance in contrast to the high-capacity orthogonal multiple access (OMA) approach that is also known as orthogonal frequency division multiple access (OFDMA). Code and power domain are some of the categories of the NOMA technique. The suggested research work mainly concentrates on the technique of NOMA, which is based on the power domain. This approach correspondingly makes use of superposition coding (SC) as well as successive interference cancellation (SIC) at source and recipient. For the fifth-generation applications, the network-level, as well as user-experienced data rate prerequisites, are successfully illustrated by various researchers.

The suggested combined methodology such as MIMO-NOMA demonstrates a synchronized iterative LMMSE system that can accomplish the optimized efficiency of symmetric MIMO NOMA with several users. To transmit the information from sender to the receiver, hybrid methodologies are confined to 2 × 2 as well as 4 × 4 antenna arrays, and thereby parameters such as PAPR, BER, SNR are analyzed and efficiency for various modulation strategies such as BPSK and QAM_j (j should vary from 8,16,32,64) are computed.

The proposed hybrid MIMO-NOMA methodologies are synchronized in terms of iterative process for optimization of LMMSE that can accomplish the optimized efficiency of symmetric for several users under different noisy conditions. From the obtained simulated results, it is found, there are 18%, 23% 16%, and 8% improvement in terms of Bit Error Rate (BER), Least Minimum Mean Squared Error (LMMSE), Peak to Average Power Ratio (PAPR), and capacity of channel respectively for Binary Phase Shift Key (BPSK) and Quadrature Amplitude Modulation (QAM) modulation techniques.

The purpose of this paper is to present an up-to-date survey on the non-orthogonal multiple access (NOMA) technique with co-operative strategy, a fast-evolving fifth-generation (5 G) technology. NOMA is used for serving many mobile users, both in power and code domains. This paper considers the power-domain NOMA, which is now discussed as NOMA.

The first part of the paper discusses NOMA-based cooperative relay systems using different relay strategies over different channel models. In various research works, the analytical expressions of many performance metrics were derived, measured and simulated for better performance of the NOMA systems. In the second part, a brief introduction to diversity techniques is discussed. The multiple input and multiple output system merged with cooperative NOMA technology, and its future challenges were also presented in this part. In the third part, the paper surveys some new conceptions such as cognitive radio, index modulation multiple access, space-shift keying and reconfigurable intelligent surface that can be combined with NOMA systems for better performance.

The paper presents a brief survey of diverse research projects being carried out in the field of NOMA. The paper also surveyed two different relaying strategies that were implemented in cooperative NOMA over different channels and compared several performance parameters that were evaluated and derived in these implementations.

The paper provides a scope for recognizable future work and presents a brief idea of the new techniques that can be united with NOMA for better performance in wireless systems.

The purpose of this study is to design a radio altimeter antenna whose production process is facilitated and can work with multiple-input multiple-output (MIMO) properties to provide space gain on the aircraft.

To create an easy-to-produce MIMO, a two-storied structure consisting of a reflector and a top antenna was designed. The dimensions of the reflector were prevented to get smaller to supply easy production. The unit cell nearly with the same dimensions of a lower frequency was protected through the original cell design. The co-planar structure with the use of a via connection was modified and a structure was achieved with no need to via for easy production, too. Finally, the antennas were placed side by side and the distance between them was optimized to achieve a MIMO operation.

As a result, an easy-to-produce, compact and successful radio altimeter antenna was obtained with high antenna parameters such as 10.14 dBi gain and 10.55 dBi directivity, and the conical pattern along with proper MIMO features, through original reflector surface and top antenna system.

Since radio altimeter antennas require high radiation properties, the microstrip antenna structure is generally used in literature. This paper contributes by presenting the radio altimeter application with antenna-reflective structure participation. The technical solutions were developed during the design, focusing on an easy manufacturing process for both the reflective surface and the upper antenna. Also, the combination of International Telecommunication Union’s recommended features that require high antenna properties was achieved, which is challenging to reach. In addition, by operating the antenna as a successful MIMO, two goals of easy production and space gain on aircraft have been attained at the same time.

In order to optimize BER and to substantiate performance measures, initially, the filter bank multicarrier (FBMC) quadrature amplitude modulation (QAM) performance metrics are evaluated with the cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) system. The efficiency of CP-OFDM, as well as FBMC/QAM that is transmitting over specific fading channels, is evaluated in terms of quality trade-off metrics over bit error rate (BER) as well as modulation order. When compared with the traditional FBMC systems, the proposed FBMC QAM system shows better performance. The performance metrics of FBMC/QAM with the inclusion of multiuser multiple-input-multiple-output (MUMIMO) is validated with worst case channel environment. The performance penalty gap that exists in CP- OFDM is compared with improved FBMC QAM in terms of both BER and OOB radiation measures. The BER trade off comparison between ML and MMSE optimally determine the prominent signal detection model for high performance FBMC QAM system.

The main objective of this research work is to provide perceptions about performance, co-channel interference avoidance as well as about the techniques that are used for minimizing the complexity of the system that is related to FBMC QAM structure for reducing intrinsic interference with higher spectral features as well as maximal likelihood (ML) detector systems.

This research work also looks at the efficiency of multiuser multiple-input-multiple-output (MU-MIMO) FBMC/QAM over nonlinear channels. Furthermore, when compared with OFDM, it also significantly reduces the penalty gap efficiency, thereby enabling the accessibility of the proposed FBMC QAM system from BER as well as implementation point of view. Finally, the signal detection is facilitated by the sub-detector and is achieved on the downlink side by making use of threshold-driven statistical measures that accurately minimize the complexity trade-off measures of the ML detector over modulation order. The computation of the proposed FBMC method’s BER performance measures was carried out through MATLAB simulation environments, as well as efficiency of the suggested work was demonstrated through detailed analyses.

This research work intend to combine the efficient MU-MIMO based transmission scheme with optimal FBMC/QAM for improved QoS over highly nonlinear channels which includes both delay spread and Doppler effects. And optimal signal detection model is facilitated at the downlink side by making use of threshold-driven statistical measures that accurately minimize the complexity trade-off measures of the ML detector over modulation order. The computation of the proposed FBMC method’s BER performance measures was carried out through MATLAB simulation environments, as well as efficiency of the suggested work was demonstrated through detailed analyses.