Experimental investigation of beam-steering applied to 2 × 2 MIMO system with single receiving RF chain and time-modulated antenna array

2020 ◽  
Vol 12 (6) ◽  
pp. 504-512
Author(s):  
Grzegorz Bogdan ◽  
Konrad Godziszewski ◽  
Yevhen Yashchyshyn

AbstractMultiple antennas and multiple radio frequency (RF) chains in both the transmitter and receiver are required in conventional radio systems employing the multiple-input multiple-output (MIMO) method. This paper presents an experimental investigation of a beam-steering time-modulated MIMO receiver with a single RF chain. Implementation of the receiver is based on a time-modulated antenna array (TMAA) and a software-defined radio. The sidebands generated inherently by the TMAA are utilized as virtual spatial channels with the beam-steering functionality. Performance of the system is investigated experimentally. The bit error rate and condition number of the channel matrix are examined for different radiation patterns in order to determine favorable configurations in a given multipath environment. Obtained results show a considerable impact of the beam-steering on the performance of MIMO transmission.

2011 ◽  
Vol 20 (03) ◽  
pp. 515-529 ◽  
Author(s):  
CONSTANTINOS I. VOTIS ◽  
PANOS KOSTARAKIS ◽  
LEONIDAS P. IVRISSIMTZIS

The design of a multiple-output transmitter for digital beamforming (DBF), Multiple-Input Multiple-Output (MIMO) and channel sounder applications, based on Direct Digital Synthesis (DDS) system is presented and investigated in terms of antenna array performance. DDS generates independently modulated signals on specific carrier frequencies and is employed as the first stage in the proposed implementation, furnishing output signal of configurable amplitude, phase and frequency. The resulting phase progression, amplitude and beamforming accuracy of a beam steering array are further investigated, showing that the proposed architecture can provide a steering beam with high accuracy. Experimental results of system performance indicate that this architecture can drive efficiently and accurately an antenna array with independent modulated RF signals, with programmable frequency, initial phase, and magnitude.


2019 ◽  
Vol 17 (1) ◽  
pp. 1
Author(s):  
Rissa Rahmania ◽  
Bambang Setia Nugroho ◽  
Fiky Yosef Suratman ◽  
Suryo Adhi Wibowo

<p><em>An electronically steerable passive array radiator (ESPAR) antenna can be used on a beamspace (BS)-multiple input multiple output (MIMO) system to reduce the device complexity. An ESPAR antenna has beamforming ability with single RF chain. However, antenna structure and channel conditions affect the number of orthogonal basis pattern which generated using Gram-Schmidt method. Based on this problem, reactance value at each parasitic element need to be optimized to form radiation pattern that required by the BS-MIMO. In this research, Genetic Algorithm (GA) is used to optimize reactance value which represented by the correlation between the desired and achieved radiation pattern, in different number of elements and different channel condition. GA is selected because this problem can be modeled as chromosome and several individual. Furthermore, the result shows in channel-ignorant and channel-aware, antenna with seven elements has a correlation in median value of 99.46% and 90.58%, respectively.</em></p><p><em> <em>Antena electronically steerable passive array radiator (ESPAR) dapat digunakan dalam sistem beamspace (BS)-multiple input multiple output (MIMO) dalam mengatasi kompleksitas perangkat. Antena ESPAR memiliki kemampuan untuk membentuk pola radiasi pada arah tertentu dengan menggunakan terminal tunggal, namun struktur antena dan kondisi kanal mempengaruhi pola dasar ortogonal yang dihasilkan melalui metode Gram Schmidt. Berdasarkan permasalahan tersebut, nilai reaktansi pada setiap elemen parasit perlu dioptimasi sehingga dapat menghasilkan pola radiasi yang dibutuhkan oleh sistem BS-MIMO. Pada penelitian ini, Algoritma Genetika digunakan untuk mengoptimasi nilai reaktansi yang direpresentasikan melalui korelasi antara pola radiasi yang dibutuhkan dengan pola radiasi yang dihasilkan, dalam jumlah elemen yang berbeda dan kondisi kanal yang berbeda. AG dipilih karena permasalahan ini dapat dimodelkan sebagai kromosom dan beberapa individual. Hasil analisis pada kondisi channel-ignorant dan channel-aware menunjukkan bahwa antena dengan tujuh elemen memiliki korelasi nilai median sebesar 99,46% dan 90,58%.</em></em></p>


Author(s):  
Prabha Kumari

In this paper we have studied about Spatial Modulation (SM) in MIMO system. Spatial modulation is a unique and newly proposed technique. Spatial modulation is a multiple input multiple output technique which provides higher throughput and gain as compared to Quadrature Amplitude Modulation. Spatial modulation is a technique which enhances the performance of MIMO system. Spatial modulation and MIMO technique are used to attracted research for its high energy and spectral efficiency because it is working on single RF chain. This paper has considered the advantages of spatial modulation and MIMO systems, using different technique to improve the bandwidth efficiency. Some of such MIMO systems applications are discussed wherein become a requirement for an emerging wireless communication system.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Kumar Yadav ◽  
Pritam Keshari Sahoo ◽  
Yogendra Kumar Prajapati

Abstract Orthogonal frequency division multiplexing (OFDM) based massive multiuser (MU) multiple input multiple output (MIMO) system is popularly known as high peak-to-average power ratio (PAPR) issue. The OFDM-based massive MIMO system exhibits large number of antennas at Base Station (BS) due to the use of large number of high-power amplifiers (HPA). High PAPR causes HPAs to work in a nonlinear region, and hardware cost of nonlinear HPAs are very high and also power inefficient. Hence, to tackle this problem, this manuscript suggests a novel scheme based on the joint MU precoding and PAPR minimization (PP) expressed as a convex optimization problem solved by steepest gradient descent (GD) with μ-law companding approach. Therefore, we develop a new scheme mentioned to as MU-PP-GDs with μ-law companding to minimize PAPR by compressing and enlarging of massive MIMO OFDM signals simultaneously. At CCDF = 10−3, the proposed scheme (MU-PP-GDs with μ-law companding for Iterations = 100) minimizes the PAPR to 3.70 dB which is better than that of MU-PP-GDs, (iteration = 100) as shown in simulation results.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3540 ◽  
Author(s):  
Yurong Wang ◽  
Aijun Liu ◽  
Kui Xu ◽  
Xiaochen Xia

Energy supply and information backhaul are critical problems for wireless sensor networks deployed in remote places with poor infrastructure. To deal with these problems, this paper proposes an airborne massive multiple-input multiple-output (MIMO) system for wireless energy transfer (WET) and information transmission. An air platform (AP) equipped with a two-dimensional rectangular antenna array is employed to broadcast energy and provide wireless access for ground sensors. By exploiting the statistical property of air-terrestrial MIMO channels, the energy and information beamformers are jointly designed to maximize the average received signal-to-interference-plus-noise ratio (SINR), which gives rise to a statistical max-SINR beamforming scheme. The scheme does not rely on the instantaneous channel state information, but still requires large numbers of RF chains at AP. To deal with this problem, a heuristic strongest-path energy and information beamforming scheme is proposed, which can be implemented in the analog-domain with low computational and hardware complexity. The analysis of the relation between the two schemes reveals that, with proper sensor scheduling, the strongest-path beamforming is equivalent to the statistical max-SINR beamforming when the number of AP antennas tends to infinity. Using the asymptotic approximation of average received SINR at AP, the system parameters, including transmit power, number of active antennas of AP and duration of WET phase, are optimized jointly to maximize the system energy efficiency. The simulation results demonstrate that the proposed schemes achieve a good tradeoff between system performance and complexity.


Author(s):  
Elsadig Saeid ◽  
Varun Jeoti ◽  
Brahim Belhaouari Samir

Future Wireless Networks are expected to adopt multi-user multiple input multiple output (MU-MIMO) systems whose performance is maximized by making use of precoding at the transmitter. This chapter describes the recent advances in precoding design for MU-MIMO and introduces a new technique to improve the precoder performance. Without claiming to be comprehensive, the chapter gives deep introduction on basic MIMO techniques covering the basics of single user multiple input multiple output (SU-MIMO) links, its capacity, various transmission strategies, SU-MIMO link precoding, and MIMO receiver structures. After the introduction, MU-MIMO system model is defined and maximum achievable rate regions for both MU-MIMO broadcast and MU-MIMO multiple access channels are explained. It is followed by critical literature review on linear precoding design for MU-MIMO broadcast channel. This paves the way for introducing an improved technique of precoding design that is followed by its performance evaluation.


Sign in / Sign up

Export Citation Format

Share Document