scholarly journals Analysis of MIMO Diversity Improvement Using Circular Polarized Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jianquan Wang ◽  
Zhaobiao Lv ◽  
Xinzhong Li
Keyword(s):  
Circular Polarization ◽  
Multiple Input Multiple Output ◽  
System Capacity ◽  
Diversity Gain ◽  
Theory Analysis ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Important Means ◽  
Multipath Scattering ◽  
Dual Polarized Antenna

MIMO (Multiple Input Multiple Output) technique is one of the important means to enhance the system capacity. Diversity gain could be acquired by using traditional ±45° dual-polarized antenna, but in the scenario where multipath scattering is not strong, power-unbalance in two polarizations caused by polarization mismatching between transmitting and receiving antennas will reduce diversity gain. This problem can be effectively solved by using circular polarized antennas. In this paper, through theory analysis and test, the improvement of MIMO diversity gain using circular polarization antenna is analyzed.

scholarly journals Partial Nulling Regularized Block Diagonalization Using Unfair Channel Selection for Post-Coding with Low-Complexity

2020 ◽  
Vol 10 (19) ◽  
pp. 6809
Author(s):  
Hyun-Sun Hwang ◽  
Jae-Hyun Ro ◽  
Young-Hwan You ◽  
Duckdong Hwang ◽  
Hyoung-Kyu Song
Keyword(s):  
Performance Enhancement ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Low Complexity ◽  
Diversity Gain ◽  
Block Diagonalization ◽  
Time Diversity ◽  
Multiple Input ◽  
Input Multiple Output ◽  
User Interference

A number of requirements for 5G mobile communication are satisfied by adopting multi-user multiple input multiple output (MU-MIMO) systems. The inter user interference (IUI) which is an inevitable problem in MU-MIMO systems becomes controllable when the precoding scheme is used. The proposed scheme, which is one of the precoding schemes, is built on regularized block diagonalization (RBD) precoding and utilizes the partial nulling concept, which is to leave part of the IUI at the same time. Diversity gain is obtained by leaving IUI, which is made by choosing the row vectors of the channel matrix that are not nullified. Since the criterion for choosing the row vectors of the channel is the power of the channel, the number of selected row vectors of the channel for each device can be unfair. The proposed scheme achieves performance enhancement by obtaining diversity gain. Therefore, the bit error rate (BER) performance is better and the computational complexity is lower than RBD when the same data rate is achieved. When the number of reduced data streams is not enough for most devices to achieve diversity gain, the proposed scheme has better performance compared to generalized block diagonalization (GBD). The low complexity at the receiver is achieved compared to GBD by using the simple way to remove IUI.

PERFORMANCE EVALUATION OF TRANSMISSION FOR MULTIUSER MIMO BROADCAST CHANNEL

2016 ◽  
Vol 78 (5-7) ◽  
Author(s):  
Mohd Syarhan Idris ◽  
Nur Idora Abdul Razak ◽  
Azlina Idris ◽  
Ruhani Ab Rahman
Keyword(s):  
Mimo System ◽  
Multiple Input Multiple Output ◽  
System Capacity ◽  
Broadcast Channel ◽  
High Data ◽  
Dirty Paper Coding ◽  
Percentage Improvement ◽  
Data Rates ◽  
Multiple Input ◽  
Input Multiple Output

Multiple Input Multiple Output (MIMO) system has been brought a great improvement in spectral efficiency and the system capacity by serving multiple users simultaneously. The mathematical model of downlink Multi-user MIMO system and its capacity has been presented as well as different precoded transmission schemes. It is to implementing the downlink MU-MIMO system, such as channel inversion (CI), block diagonalization (BD), dirty paper coding (DPC) and tomlinsonharashimaprecoding (THP). It is because, in wireless and mobile communication system has been requires a reliable transmission of high data rates under various channel type different scenarios and reduce MU interference in the system.   These compares the method of transmission for broadcast channel (BC) and propose the best one method that outperforms existing technique with percentage improvement from the worst performance.

scholarly journals A Fast Adaptive Receive Antenna Selection Method in MIMO System

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Chaowei Wang ◽  
Weidong Wang ◽  
Cheng Wang ◽  
Shuai Wang ◽  
Yang Yu
Keyword(s):  
Mimo Systems ◽  
Antenna Selection ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
System Capacity ◽  
Adaptive Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Hardware Costs ◽  
Receive Antenna

Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO) systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.

Effect of Antenna Layout on the Capacity of Massive MIMO

2014 ◽  
Vol 716-717 ◽  
pp. 1194-1198
Author(s):  
Xiao Yu Li ◽  
Xiao Fei Zhang ◽  
Da Zhuan Xu ◽  
Qui Ming Zhu
Keyword(s):  
Channel Model ◽  
Narrow Band ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
System Capacity ◽  
Antenna Aperture ◽  
Multiple Input ◽  
Flat Fading ◽  
Input Multiple Output ◽  
Capacity Performance

This paper addresses the problem of the effect of different antenna layouts on the capacity of massive multiple-input multiple-output (MIMO) system capacity. Based on the narrow-band, flat fading channel model, the effect of scattering environment and antenna layout are considered by incorporating the power azimuth spectrum (PAS) and the array manifold vector. Under the same antenna aperture, six antenna layouts are investigated among which the UCA yields the best capacity while ULA yields the lowest capacity. The more symmetric the antenna geometry is, the better capacity performance it has.

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