scholarly journals MIMO OTA Testing Based on Transmit Signal Processing

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jesús Gutiérrez ◽  
Jesús Ibáñez ◽  
Jesús Pérez
Keyword(s):  
Signal Processing ◽  
Closed Form ◽  
Linear Combination ◽  
Multiple Input Multiple Output ◽  
Mimo Channel ◽  
Multiple Input ◽  
Channel Conditions ◽  
Input Multiple Output

Usually, multiple-input-multiple-output (MIMO) testbeds are combined with channel emulators for testing devices and algorithms under controlled channel conditions. In this work, we propose a simple methodology that allows over-the-air (OTA) MIMO testing using a MIMO testbed solely, avoiding the use of channel emulators. The MIMO channel is emulated by linearly combining the signals at the testbed transmitter. The method is fully flexible, so it is able to emulate any equivalent baseband narrowband MIMO channel by adequately selecting the weights of the linear combination. We derive closed-form expressions for the computation of such weights. To prove its feasibility, the method has been implemented and tested over a commercial MIMO testbed.

scholarly journals Conceiving Inferential Prototypes of MIMO Channel Models via Buckingham’s Similitude Principle for 30+ GHz through THz Spectrum

2021 ◽  
Vol 9 (3) ◽  
pp. 1-35
Author(s):  
Perambur Neelakanta ◽  
Dolores De Groff
Keyword(s):  
Multiple Input Multiple Output ◽  
Path Loss ◽  
Spatial Multiplexing ◽  
Mimo Channel ◽  
Channel Models ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Channel Statistics ◽  
Wave Range ◽  
Test Spectrum

Facilitating newer bands of ‘unused’ segments (windows) of RF spectrum falling in the mm-wave range (above 30+ GHz) and seeking usable stretches across unallocated THz spectrum, could viably be considered for Multiple Input Multiple Output (MIMO) communications. This could accommodate the growing needs of multigigabit 3G/4G applications in outdoor-based backhauls in picocellular networks and in indoor-specific multimedia networking. However, in contrast with cellular and Wi-Fi, wireless systems supporting sub-mm wavelength transreceive communications in the outdoor electromagnetic (EM) ambient could face “drastically different propagation geometry”; also, in indoor contexts, envisaging pertinent spatial-multiplexing with directional, MIMO links could pose grossly diverse propagation geometry across a number of multipaths; as such, channel-models based on stochastic features of diverse MIMO-specific links in the desired test spectrum of mm-wave/THz band are sparsely known and almost non-existent. To alleviate this niche, a method is proposed here to infer sub-mm band MIMO channel-models (termed as “prototypes”) by judiciously sharing “similarity” of details available already pertinent to traditional “models” of lower-side EM spectrum, (namely, VLF through micro-/mm-wave). Relevant method proposed here relies on the “principle of similitude” due to Edgar Buckingham. Exemplar set of “model-to-(inferential)-prototype” transformations are derived and prescribed for an exhaustive set of fading channel models as well as, towards estimating path-loss of various channel statistics in the high-end test spectrum.

scholarly journals High-Performance Multiple-Input Multiple-Output Antenna System For 5G Mobile Terminals

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1090 ◽  
Author(s):  
Mujeeb Abdullah ◽  
Saad Hassan Kiani ◽  
Lway Faisal Abdulrazak ◽  
Amjad Iqbal ◽  
M. A. Bashir ◽  
...  
Keyword(s):  
Multiple Input Multiple Output ◽  
Antenna System ◽  
Mimo Channel ◽  
Slot Antenna ◽  
Total Efficiency ◽  
Multiple Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Metal Casing ◽  
Multiple Antenna System

In this paper, the systematic design of a multiple antenna system for 5G smartphone operating at 3.5 GHz for multiple-input multiple-output (MIMO) operation in smartphones is proposed. The smartphone is preferred to be lightweight, thin, and attractive, and as a result metal casings have become popular. Using conventional antennas, such as a patch antenna, Inverted-F antennas, or monopole, in proximity to metal casing leads to decreasing its total efficiency and bandwidth. Therefore, a slot antenna embedded in the metal casing can be helpful, with good performance regarding bandwidth and total efficiency. The proposed multiple antenna system adopted the unit open-end slot antenna fed by Inverted-L microstrip with tuning stub. The measured S-parameters results agree fairly with the numerical results. It attains 200 MHz bandwidth at 3.5 GHz with ports isolation of (≤−13 dB) for any two antennas of the system. The influence of the customer’s hand for the proposed multiple antenna system is also considered, and the MIMO channel capacity is computed. The maximum achievable MIMO channel capacity based on the measured result is 31.25 bps/Hz and is about 2.7 times of 2 × 2 MIMO operation.

scholarly journals Linear Precoding Designs for MIMO VLC Using Multi-Color LEDs under Multiple Lighting Constraints

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 408 ◽  
Author(s):  
Ye Xiao ◽  
Yi-Jun Zhu ◽  
Zheng-Guo Sun
Keyword(s):  
High Speed ◽  
Mean Squared Error ◽  
Transmission Rate ◽  
Multiple Input Multiple Output ◽  
Visible Light Communication ◽  
Mimo Channel ◽  
Practical Applications ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Technology

Multiple-input multiple-output (MIMO) technology as an efficient approach to improve the transmission rate in visible light communication (VLC) has been well studied in recent years. In this paper, we focus on the MIMO VLC system using multi-color LEDs in the typical indoor scenario. Besides the correlation of the MIMO channel, the multi-color crosstalk interference and quadrangle chromaticity region are also considered to increase the practicality of this system. With the constraints of power, amplitude and chromaticity, an iterative algorithm to minimize mean-squared-error (MSE) is proposed to jointly design the precoder and equalizer. Our proposed algorithm provides an effective method to get the optimal precoder by updating optimization variables iteratively. As the equalizer matrix is fixed at each iteration, the main non-convex precoding design problem is transformed into a convex optimization problem and then solved. With the utilization of multi-color LEDs, our proposed precoding method would be promising to promote the practical applications of high-speed indoor optical wireless communication. Simulation results show that our proposed method owns better performance than conventional chromaticity-fixed schemes and zero-forcing precoding designs.

Optimization of Light Sampling Coupler in All-Optical Multiple-Input Multiple-Output Signal Processing

2017 ◽  
Vol 37 (4) ◽  
pp. 0406004
Author(s):  
范鑫磊 Fan Xinlei ◽  
付松年 Fu Songnian ◽  
唐明 Tang Ming ◽  
刘德明 Liu Deming
Keyword(s):  
Signal Processing ◽  
Output Signal ◽  
Multiple Input Multiple Output ◽  
Multiple Input ◽  
All Optical ◽  
Input Multiple Output

scholarly journals Secure downlink transmission with finite resolution analog beamforming in massive multiple-input multiple-output system

2018 ◽  
Vol 14 (9) ◽  
pp. 155014771880225 ◽  
Author(s):  
Xianyu Zhang ◽  
Daoxing Guo ◽  
Kongzhe Yang ◽  
Silin Xie
Keyword(s):  
Closed Form ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Artificial Noise ◽  
Secrecy Rate ◽  
Finite Resolution ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Output System ◽  
Ergodic Secrecy Rate

To reduce the number of radio-frequency chains of base station, the use of finite resolution analog beamforming is desirbale in massive multiple-input multiple-output system. This article investigates the secure downlink massive multiple-input multiple-output data transmission with artificial noise at base station in the presence of a multi-antenna passive eavesdropper. The achievable user’s ergodic information rate and ergodic capacity of the eavesdropper are analyzed in detail, respectively. With maximum ratio transmission or maximum ratio combining, we derive closed-form expressions for a tight lower bound on ergodic secrecy rate and tight upper bound for secrecy outage probability. Based on these analytical expressions, the effects of various system parameters on secrecy performance, such as power allocation factor, number of eavesdropper’s antennas, number of the user terminals, total transmission power, and finite resolution analog beamforming parameters, are investigated in detail. Also, the optimal power allocation scheme between data and artificial noise signals is achieved in closed form to maximize the ergodic secrecy rate. In addition, we derive the conditions that the secure massive multiple-input multiple-output system need to meet to obtain a positive secrecy rate. Finally, numerical simulation results validate the system’s secrecy performance and verify all the theoretical analytical results.

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