5G MIMO Systems Research Articles

Understanding Wireless ChannelsThrough NeRF2

Despite Maxwell's formulation of the electromagnetic wave laws over a century and a half ago, accurately modeling the transmission of RF signals within electrically complex environments continues to be a formidable challenge. This complexity arises from intricate interactions of RF signals with various obstacles, such as reflections and diffractions. Inspired by the effective utilization of neural networks in computer vision for representing optical fields, this paper introduces NeRF2, a novel neural radio-frequency radiance field. NeRF2 conceptualizes a continuous, volumetric scene function to interpret RF signal propagation. Uniquely, NeRF2, once trained with limited signal measurements, can predict the characteristics and reception of a signal at an arbitrary point, given the transmitter's location. Functioning as a physical-layer neural network, NeRF2 amalgamates learned statistical models with physical ray tracing to create synthetic datasets, tailored for the training needs of application-layer artificial neural networks (ANNs). This integration, termed "turbo-learning," combines authentic and synthetic datasets, significantly augmenting ANNs' training efficacy. Experimental results illustrate that turbo-learning can substantially improve performance, with an estimated 50% enhancement. The efficacy of NeRF2 is further underscored in its applications in indoor localization and 5G MIMO systems.

An analysis of 5G-MIMO communication system based SS for centralized cooperative and non-cooperative users

The purpose of 5G-MIMO communication systems is to boost the intensity of the received signal, and facilitate the application of the users’ apparatus. However, in band-grabbing systems such as these, the accessibility of a spectrum is hindered by gridlocks. Also, to be considered is the spectrum’s waveform, which is the type that contends with 5G networks specifically. This undertaking involves the development of a 5G-MIMO communication system based SS, in which the spectrum is enhanced, by way of a spectrum sensing (SS) algorithm. By replicating the energy detection procedure, this recommended SS algorithm engages the cosine law to filter the traffic signal, and subsequently portions it using the Welch algorithm. The Hann algorithm is then utilized, to window the traffic signal, to damp the high power delivered to the MIMO. The key role, of the SS algorithm, is to sense a spectrum for 5G-MIMO communication system, with the capacity to damp the MIMO effect for a variety of waveforms. The SS algorithm expressions are applicable for both non-cooperative and centralized cooperative users. For each expression, an examination was performed for waveforms used by 5G-MIMO communication systems. This included filtered-orthogonal frequency division multiplexing (F-OFDM), universal filtered multi-carrier (UFMC), and filter bank multi-carrier (FBMC) waveforms. The operating parameters, including SNR, the signal span and power, the antenna count, as well as the types of modulation for both non-cooperative and centralized cooperative users, were scrutinized. The simulation results revealed a notable achievement for the parameters lower than zero dB of SNR, greater than 95% global detection probability, less than 1% global system error probability, and less than 1% global false alarm probability. An evaluation of the recommended system’s parameters discloses its superiority, in comparison to other previously developed systems.

A dual wideband high gain 2 × 2 multiple‐input‐multiple‐output monopole antenna with an end‐launch connector model for 5G millimeter‐wave mobile applications

This article presents the design, analysis, and realization of a new printed multiple-input-multiple-output (MIMO) antenna with a very high gain and wide bandwidth for the millimeter-wave (mm-wave) 28/38 GHz fifth generation (5G) new radio (NR) applications. The proposed MIMO antenna consists of four identical patch elements in a 2 × 2 configuration to achieve high gain with wide operating bandwidth. The proposed antenna holds an attractive compact size of 31.891 × 37.528 mm2. The proposed MIMO configuration is designed on a 0.508 mm thick Rogers-5870 substrate material with a loss tangent of 0.0009 and a relative dielectric constant of 2.33. An effective technique for folding the feed line and applying a new protruding ground is introduced to obtain good mutual coupling. The fabricated prototype of the proposed antenna is tested to verify the simulation results for the validation of the suggested design approach. The suggested MIMO antenna exhibits −10 dB impedance bandwidth of 2.6 GHz (27.4–30.0 GHz) and 3.3 GHz (36.7–40.0 GHz) to cover the intended frequency range for 5G applications with isolation less than −22 band peak gains of 18 and 14.5 dBi at 27.5 and 38.8 GHz, respectively. To validate the MIMO performance of the proposed antenna several MIMO diversity parameters such as mean effective gain (MEG), envelope correlation coefficient (ECC), and diversity gain (DG) are evaluated. Determined results indicate ECC < 0.001, DG > 9.995, and an average MEG of −3 dB at the operating bands. The proposed antenna exhibits good agreement between the simulated and measured results, which confirm its suitability for forthcoming mm-wave 5G MIMO systems and services.

Analysis and Design of an Efficient and Novel MIMO Antenna for 5G Smart Phones Using FDTD and FEM

A novel and compact antenna element is analyzed and designed to achieve an efficient 4x4 MIMO antenna for a mobile phone at 3.5 GHz band for 5G communication. FTDT and FEM techniques are used to analyze and compare modeling accuracy of the proposed MIMO antenna. It has achieved a minimum isolation of 19.7dB between two antennas with radiation efficiency of 86%. The improved isolation and efficiency for the proposed MIMO antenna has been achieved without any decoupling structure between antennas, instead larger separation between elements due to compact size of the proposed element facilitated to achieve good performance. Pattern diversity is also achieved by arranging adjacent asymmetric antennas in reverse direction with each other. The envelope correlation coefficient (ECC) is less than 0.002 and Channel Capacity loss (CCL) is also less than 0.4 bps/Hz in the whole frequency band (3.36-3.66 GHz), which is suitable for 5G MIMO systems.

A Simulational Performance of 5G MIMO Systems applying UFMC( Universal Filtered Multicarrier) Study

The advanced wireless communication system uses the new technology, preparing the limited radio spectrum and its low expensive resource. The Scenario of Wireless communication is needed for the flexible mechanism with available time and frequency resources. The OFDM system, which is a multicarrier process with a remote framework in Long Term Evolution (LTE), 4G, and 5G. Using of UFMC(Universal_Filtered_Multicarrier)system with OFDM system symmetrical recurrence division multiply with modulation system and the correlation between them. Using of UFMC system with QAM into the MIMO system the result of subchannel, the model channel correlation recreated in “ A Simulational Performance of 5G MIMO Systems applying UFMC (Universal_Filtered_Multicarrier ) Study” result shown in MATLAB.

A CMOS Dual-Polarized Phased-Array Beamformer Utilizing Cross-Polarization Leakage Cancellation for 5G MIMO Systems

This article introduces a power-efficient and low-cost CMOS 28-GHz phased-array beamformer supporting fifth-generation (5G) dual-polarized multiple-in-multiple-out (MIMO) (DP-MIMO) operation. To improve the cross-polarization (cross-pol.) isolation degraded by the antennas and propagation, a power-efficient analog-assisted cross-pol. leakage cancellation technique is implemented. After the high-accuracy cancellation, more than 41.3-dB cross-pol. isolation is maintained along with the transmitter array to the receiver array. The element-beamformer in this work adopts the compact neutralized bi-directional architecture featuring a minimized manufacturing cost. The proposed beamformer achieves 22% per path TX-mode efficiency and a 4.9-dB RX-mode noise figure. The required on-chip area for the beamformer is only 0.48 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . In over-the-air measurement, a 64-element dual-polarized phased-array module achieves 52.2-dBm saturated effective isotropic radiated power (EIRP). The 5G standard-compliant OFDMA-mode modulated signals of up to 256-QAM could be supported by the 64-element modules. With the help of the cross-pol. leakage cancellation technique, the proposed array module realizes improved DP-MIMO EVMs even under severe polarization coupling and rotation conditions. The measured DP-MIMO EVMs are 3.4% in both 64-QAM and 256-QAM. The consumed power per beamformer path is 186 mW in the TX mode and 88 mW in the RX mode.

A Balun Bandpass Filter to Facilitate the Design of Dual-Polarized Dipole Antenna

A dipole antenna based on a balun bandpass filter (BPF) is developed in this paper. The balun BPF employs two U-shaped resonators settled on the left side of the open-circuited transmission line and two L-shaped stubs to produce signals with equal amplitude and inverse phase. In this way, the volume of the balun BPF is reduced by half, and the distance between two output ports is dramatically decreased. Then, the balun BPF is integrated with a dipole. Instead of the traditional Γ-shaped line with a wide balun ground, two thin microstrip lines with width of 1 mm are adopted to connect the dipole and the balun BPF. The antenna bandwidth is further extended due to the fusion of the resonance of the dipole and balun BPF. As a result, the proposed antenna can operate from 4350 to 5025 MHz (covering the n79 band of 5G NR, 4400 MHz–5000 MHz), yielding a good filtering performance in the stopband. The measured half-power beamwidth is ranging from 61° to 63° and the measured gain is ranging from 7.95 to 8.5 dBi in the passband. This new balun BPF and the dual-polarized dipole based on it have great potential to be applied in 5G MIMO systems.

Poynting Localized Energy: Method and Applications to Gain Enhancement in Coupled Antenna Systems

We present a general and comprehensive approach to evaluate spatio-temporal localized energy around radiating structures of arbitrary shapes and excitation signals. The method utilizes the finite-difference time-domain (FDTD) algorithm to calculate the Poynting localized energy for any antenna by working directly with computed fields, rather than source currents. It is established that this localized energy is fundamentally different from the classical antenna reactive energy associated with frequency-domain Q-factors of electrically small antennas. The proposed localized energy theory leads to the formulation of new performance evaluation measures, effectively going beyond traditional S-parameters and far-field patterns, which are then applied in several design examples involving strongly coupled arrays and weakly coupled antenna systems. It was found that gain enhancement caused by strong mutual coupling in the near zone (directors in Yagi-Uda systems or split-ring resonator arrays) is closely correlated with localized energy enhancement (but such correlation does not hold in weak mutual coupling scenarios). The new performance metrics are also used to generate spatial distributions for energy localization in MIMO printed dipoles. We propose that this proposed localized energy concept and the apparatus developed to investigate its relevant new data can assist in implementation of ultrahigh gain closely spaced antenna elements needed for the upcoming sub-6 GHz/mmWave 5G MIMO systems.

A Full-FoV Autonomous Hybrid Beamformer Array With Unknown Blockers Rejection and Signals Tracking for Low-Latency 5G mm-Wave Links

This paper demonstrates an eight-element multiple-input-multiple-output (MIMO) hybrid beamforming receiver array with autonomous millimeter-wave (mm-Wave)/RF front-end beamforming and digital baseband beamforming. It enables autonomous dynamic suppression of unknown blockers and beamforming on unknown desired signals, without knowing their carrier frequency, angle-of-arrival (AoA), and modulation scheme as a priori. After autonomous cancellation of an in-band/cochannel wideband-modulated blocker, a wideband-modulated desired signal is measured with high SNR, achieving −25.7-dB EVM for 6-Gb/s 64 QAM and −31.8-dB EVM for 1.6-Gb/s 256 QAM. Without baseband DSP beam-searching, the closed-loop mm-Wave/RF front-end beamformer (BF) realizes $\mu \text{s}$ rapid response per stage, 100-to- $1000\times $ faster than existing mm-Wave analog/digital BFs with DSP beam-searching. The eight-element MIMO receiver array covers a wide frequency range (23–30 GHz) and the full field-of-view (FoV) to address future low-latency applications of practical 5G MIMO systems. To the best of our knowledge, this is the first MIMO receiver array enabling autonomous wideband-modulated 64-/256-QAM blocker rejection and desired signal beamforming with $\mu \text{s}$ response time.