scholarly journals Beam division multiple access for millimeter wave massive MIMO: Hybrid zero-forcing beamforming with user selection

Author(s):  
Hong Son Vu ◽  
Kien Truong ◽  
Minh Thuy Le

<p>Massive multiple-input multiple-output (MIMO) systems are considered a promising solution to minimize multiuser interference (MUI) based on simple precoding techniques with a massive antenna array at a base station (BS). This paper presents a novel approach of beam division multiple access (BDMA) which BS transmit signals to multiusers at the same time via different beams based on hybrid beamforming and user-beam schedule. With the selection of users whose steering vectors are orthogonal to each other, interference between users is significantly improved. While, the efficiency spectrum of proposed scheme reaches to the performance of fully digital solutions, the multiuser interference is considerably reduced.</p>

Author(s):  
Naraiah R , Et. al.

Wireless communications has gotten one of the quickest developing zones in our advanced life and makes colossal effect on practically every component of our day by day life. 5G should support a large number of new applications with a wide assortment of prerequisites, including higher pinnacle and client information rates, diminished dormancy, improved indoor inclusion, expanded number of gadgets, etc. The normal traffic development in at least a long time from now can be fulfilled by the consolidated utilization of more range, higher spectral efficiency, and densification of cells. The increment in spectral effectiveness will improve the throughput of the system which straightforwardly serves the Enhanced Mobile Broad band use instance of the 5G assistance. In massive Multiple-Input Multiple-Output (M-MIMO) systems few hundred quantities of antennas are conveyed at each base station (BS) to serve a moderately modest number of single-reception apparatus terminals with multiuser, giving higher information rate and lower idleness. Massive Multiple-Input Multiple-Output is the arising innovation in cell system for higher information rate correspondence. It utilizes enormous number of communicating reception apparatus at the base station which is made conceivable by the radio wire cluster which can be electronically steerable and adequately utilized for shaft framing. Spectral proficiency is the vital boundary to be improved in expanding throughput. The system execution under different commonsense limitations and conditions, for example, restricted soundness block length, number of base station (BS) antennas, and number of dynamic clients are assessed through simulation.  


Author(s):  
Muhsin Muhsin ◽  
Afina Lina Nurlaili ◽  
Aulia Saharani ◽  
Indah Rahmawti Utami

<span>Massive internet of things (IoT) in 5G has many advantages as a future technology. It brings some challenges such as a lot of devices need massive connection. In this case, multiple-input multiple-output (MIMO) systems offer high performance and capacity of communications. There is a challenge of correlation between antennas in MIMO. This paper proposes three-sectors MIMO base station antenna for 5G-New Radio (5G-NR) band N77 with dual polarized configuration to reduce the correlation. The proposed antenna has a maximum coupling of -16.90 dB and correlation below 0.01. The obtained bit error rate (BER) performance is very close to non-correlated antennas with bandwidth of 1.87 GHz. It means that the proposed antenna has been well designed.</span>


Author(s):  
Ashu Taneja ◽  
Nitin Saluja

Background: The paper considers the wireless system with large number of users (more than 50 users) and each user is assigned large number of antennas (around 200) at the Base Station (BS). Objective: The challenges associated with the defined system are increased power consumption and high complexity of associated circuitry. The antenna selection is introduced to combat these problems while the usage of linear precoding reduces computational complexity. The literature suggests number of antenna selection techniques based on statistical properties of signal. However, each antenna selection technique suits well to specific number of users. Methods: In this paper, the random antenna selection is compared with norm-based antenna selection. It is analysed that the random antenna selection leads to inefficient spectral efficiency if the number of users are more than 50 in Multi-User Multiple-Input Multiple Output (MU-MIMO) system. Results: The paper proposes the optimization of Energy-Efficiency (EE) with random transmit antenna selection for large number of users in MU-MIMO systems. Conclusion: Also the computation leads to optimization of number of transmit antennas at the BS for energy efficiency. The proposed algorithm results in improvement of the energy efficiency by 27% for more than 50 users.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Soobum Cho ◽  
Sang Kyu Park

Orthogonal frequency division multiple access (OFDMA) is a key multiple access technique for the long term evolution (LTE) downlink. However, high peak-to-average power ratio (PAPR) can cause the degradation of power efficiency. The well-known PAPR reduction technique, dummy sequence insertion (DSI), can be a realistic solution because of its structural simplicity. However, the large usage of subcarriers for the dummy sequences may decrease the transmitted data rate in the DSI scheme. In this paper, a novel DSI scheme is applied to the LTE system. Firstly, we obtain the null subcarriers in single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems, respectively; then, optimized dummy sequences are inserted into the obtained null subcarrier. Simulation results show that Walsh-Hadamard transform (WHT) sequence is the best for the dummy sequence and the ratio of 16 to 20 for the WHT and randomly generated sequences has the maximum PAPR reduction performance. The number of near optimal iteration is derived to prevent exhausted iterations. It is also shown that there is no bit error rate (BER) degradation with the proposed technique in LTE downlink system.


Author(s):  
Sirichai Hemrungrote ◽  
Toshikazu Hori ◽  
Mitoshi Fujimoto ◽  
Kentaro Nishimori

Multiple-Input Multiple-Output (MIMO) wireless communication technology is expected to improve the channel capacity over the limited bandwidth of existing networks. Since urban MIMO systems have complex propagation characteristics, the channel capacity cannot be estimated using a simple method. Hence, we introduce channel capacity characteristics to urban MIMO systems by using a combination of imaging and ray-launching methods as a ray-tracing scheme. A simulation based on these methods with variable parameters can reproducibly estimate various urban propagation characteristics and discriminate the effects of the urban model and antenna configurations. The characteristics of the Signal-to-Noise Ratio (SNR), the channel capacity, the spatial correlation, as well as the path visibility are then determined from the results of the simulation. The parameter called path visibility introduced in our previous study is considered again herein. We clarify that only this single parameter can be used to determine the channel capacity characteristics in urban MIMO scenarios. This parameter also provides guidance in determining the appropriate range for the base station (BS) height.


Frequenz ◽  
2020 ◽  
Vol 74 (9-10) ◽  
pp. 359-368
Author(s):  
Deming Chu ◽  
Anzhong Hu

AbstractIn this paper, we study the optimization of two tilt angles corresponding to two antenna arrays in each base station (BS) of a massive multiple-input multiple-output system. We consider two scenarios with perfect channel state information (CSI) and imperfect CSI. In the limit of the number of the BS antennas, the channel orthogonality is employed to derive the limit and the lower bound of the throughputs. By maximizing the lower bound or the limit throughput, the two antenna tilt angles are optimized. Simulation results show that the throughput performance can be improved with the designed tilt angles.


2018 ◽  
Vol 218 ◽  
pp. 03009
Author(s):  
Desy Agustin ◽  
Nachwan Mufti Adriansyah ◽  
Muhsin

In today’s modern telecommunications systems, makes the number of studies and development of multiple antennas and multiple-input multiple-output (MIMO) systems to achieve high reliability and low complexity. One attractive approach to improve that performance is using technique transmit diversity which is spacetime block coding and receiver diversity i.e. zero forcing EVCM (ZF EVCM). Although some earlier MIMO standards were develop some space-time codes like (O-STBC)and (Q-OSTBC) to provide high reliability but they are limited able to achieve orthogonality. In this research will be proposed a MIMO system scheme which is an improvement of QOSTBC that used a transmission diversity technique. This improvement from QOSTBC is Twice QOSTBC uses a provision in two codeword matrices to be sent are arranged diagonally so as to have higher levels of orthogonality. In this case Twice QOSTBC highly structured (4x1) can be replaced as an equivalent EVCM channel H. The proposed Twice-QOSTBC’s results outperform other QOSTBC techniques with a difference around 3 dB for single-input multi-input (MISO) input configuration at 10-6 BER and receiver ZF EVCM has a very similar structure as the code matrix S of the underlying Twice QSTBC which can eliminates the system complexity.


Author(s):  
Mai Thi Phuong Le ◽  
Hung Le Nguyen ◽  
Hieu Van Nguyen ◽  
Vien Duy Nhat Nguyen

In this paper, we investigate the spectral efficiency (SE) of a multi-user multiple-input multiple-output (MU-MIMO) antenna network in full-duplex (FD) regime, where uplink (UL) and downlink (DL) users simultaneously share the same time and frequency resources. Zero-forcing approach is applied efficiently to precode/detect signals in both UL and DL. To achieve the SE maximization, we formulate an optimized problem where the transmit power of Base station (BS) and users are jointly considered. Numerical results are used to show that the proposed algorithm may bring significant SE gain over the previous approaches under realistic channel conditions.


Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2884 ◽  
Author(s):  
Kai Zhai ◽  
Zheng Ma ◽  
Xianfu Lei

In this paper, we estimate the uplink performance of large-scale multi-user multiple-input multiple-output (MIMO) networks. By applying minimum-mean-square-error (MMSE) detection, a novel statistical distribution of the signal-to-interference-plus-noise ratio (SINR) for any user is derived, for path loss, shadowing and Rayleigh fading. Suppose that the channel state information is perfectly known at the base station. Then, we derive the analytical expressions for the pairwise error probability (PEP) of the massive multiuser MMSE–MIMO systems, based on which we further obtain the upper bound of the bit error rate (BER). The analytical results are validated successfully through simulations for all cases.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Abdelhak Boukharouba ◽  
Marwa Dehemchi ◽  
Asma Bouhafer

AbstractIn this study, we present efficient detection and precoding algorithms for massive multi-user multiple-input multiple-output wireless system. To reduce the computational complexity due to large matrix inversion, the proposed algorithms are an enhanced version of zero forcing scheme based on QR matrix decomposition for both uplink and downlink systems. Through extensive numerical experiments, we demonstrate that the proposed algorithms outperform the recently published ones in terms of performance and complexity.


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