scholarly journals Hybrid Precoding Design Using MMSE Baseband Precoder for mm-Wave Multi-User MIMO Systems

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3486-3490
Keyword(s):  
Communication Networks ◽  
Antenna Arrays ◽  
Mimo Systems ◽  
Minimum Mean Square Error ◽  
Path Loss ◽  
Cellular Systems ◽  
Base Stations ◽  
System Capacity ◽  
Achievable Rate ◽  
Hybrid Precoding

For future 5G wireless communication networks, millimeter-wave (mmWave) cellular systems is considered to be the key enabling technology because of its high data rates, low latency, high system capacity, and huge available bandwidths. However, multiuser networks in mmWave frequency bands encounter high path loss and interference, thus degrading the performance. Applying large antenna arrays at the base stations (BS) in order to achieve high beamforming gains with the help of precoding techniques is an efficient way of improving the performance of the system. Although multi-user beamforming can improve spectral efficiencies, full digital beamforming strategies used in the conventional microwave systems increase the hardware cost and consumes high power for large number of antennas in mmW systems. In this paper, a low-complexity multi-user hybrid precoding structure is proposed for mmWave multiple input multiple output (MIMO) channels utilizing Minimum Mean Square Error (MMSE) precoders at the BS with perfect channel knowledge. Simulations show that the achievable rate obtained by the proposed hybrid precoding scheme is very close to the single-user rate and also performs better compared to other hybrid precoding approaches.

scholarly journals Realistic antenna modeling for MIMO systems in microcell scenarios

2005 ◽  
Vol 2 ◽  
pp. 141-146
Author(s):  
C. Waldschmidt ◽  
C. Kuhnert ◽  
T. Fügen ◽  
W. Wiesbeck
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Mimo Systems ◽  
Mimo System ◽  
Cellular Systems ◽  
Handheld Devices ◽  
Communication Link ◽  
Cellular Phones ◽  
Power Budget ◽  
Spaced Antennas

Abstract. This paper shows the potential of MIMO in cellular systems, where small handheld devices are used for the terminals. A complete model of a MIMO communication link is used to integrate accurate antenna modelling into MIMO system simulations. All different effects of mutual coupling between closely spaced antennas are considered. The efficiency or power budget respectively of the antenna arrays in the terminals, which are influenced by mutual coupling effects, is taken into account. Capacity simulation results based on a channel obtained from ray-tracing simulations are shown with cellular phones with up to three Inverted-F antennas.

scholarly journals Power density of rectangular microstrip patch antenna arrays for 5G indoor base station

2020 ◽  
Vol 19 (3) ◽  
pp. 1367
Author(s):  
Nor Adibah Ibrahim ◽  
Tharek Abd Rahman ◽  
Razali Ngah ◽  
Omar Abd Aziz ◽  
Olakunle Elijah
Keyword(s):  
Power Density ◽  
Antenna Arrays ◽  
Base Station ◽  
Small Cell ◽  
Base Stations ◽  
System Capacity ◽  
High Data ◽  
Communication Devices ◽  
Set Up ◽  
Cell Base

The fifth-generation (5G) network has been broadly investigated by many researchers. The capabilities of 5G include massive system capacity, incredibly high data rates everywhere, very low latency and the most important point is that it is exceptionally low device cost and low energy consumption. A key technology of 5G is the millimeter wave operating at 28 GHz and 38 GHz frequency bands which enable massive MIMO and small cell base station densification. However, there has been public concern associated with human exposure to electromagnetic fields (EMF) from 5G communication devices. Hence, this paper studies the power density of a 5G antenna array that can be used for the indoor base station. The power density is the amount of power or signal strength absorbed by a receiver such as the human body located a distance from the base station. To achieve this, the design of array antennas using CST software at 28 GHz, fabrication and measurement were carried out in an indoor and hallway environment. The measurement processes were set up at IC5G at UTM Kuala Lumpur in which the distance of the transmitter to receiver where 1 m, 4 m, 8 m, and 10 m. In this study, the measured power density is found to be below the set limit by ICNIRP and hence no health implication is feared. Regardless, sufficient act of cautionary has to be applied by those staying close to small cell base stations and more studies are still needed to ensure the safety of use of 5G base stations.

scholarly journals Effect of Membership Functions and Data Size on the Performance of ANFIS-Based Model for Predicting Path Losses in the VHF and UHF Bands

2021 ◽  
Author(s):  
Surajudeen-Bakinde N. T. ◽  
◽  
Nasir Faruk ◽  
Abubakar Abdulkarim ◽  
Abdulkarim A. Oloyede ◽  
...  
Keyword(s):  
Path Loss ◽  
Cellular Systems ◽  
Training Data ◽  
Base Stations ◽  
Membership Functions ◽  
Anfis Model ◽  
System Parameters ◽  
Loss Prediction ◽  
Path Loss Prediction ◽  
And Training

This paper investigates the effect of number and shape of membership function (MF), and training data size on the performance of ANFIS model for predicting path losses in the VHF and UHF bands in built-up environments. Path loss propagation measurements were conducted in four cities of Nigeria over the cellular and broadcasting frequencies. A total of 17 broadcast transmission and cellular base stations were utilized for this study. From the results obtained, it can be concluded for the broadcasting bands that the generalized bell MF shows better performance with an average RMSE of 3.00 dB across all the routes, followed by gaussian, Pi, trapezoid and triangular MFs in that other with average RMSE values of 3.09 dB, 3.11 dB, 3.16 dB and 3.23 dB respectively. For the cellular systems, Triangular MF outperformed other MFs with the lowest average RMSE. The generalized bell MF was found to be suited for WCDMA band while triangular MF is most suited for GSM band. Furthermore, it can also be concluded that the higher the number of membership functions, the lower the RMSE, whereas, a decrease in the data size leads to a reduction in the RMSE values. The findings of this study would help researchers and network planners to make a more informed decision on choosing appropriate system parameters when modeling ANFIS models for path loss prediction.

scholarly journals Implementation of Hybrid Precoding for MIMO System Using Kalman Approach

2021 ◽  
Vol 9 (VII) ◽  
pp. 3380-3385
Author(s):  
Shamlet Divya
Keyword(s):  
Antenna Arrays ◽  
Mimo System ◽  
Multipath Propagation ◽  
Path Loss ◽  
Practical Method ◽  
Antenna System ◽  
Main Role ◽  
60 Ghz ◽  
Hardware Complexity ◽  
Hybrid Precoding

Multiple antenna system in communication is a main role to serve a multiple users at a time simultaneously in future wireless communication system. The MIMO specifically refers to practical method for sending and receiving the data more than one signal at a time over the same radio frequency channel by exploring the multipath propagation. MIMO is fundamentally a special form smart antenna system modified to enhance the performance of a data signal, such as Beamforming / Precoding and diversity. In millimeter wave 60 GHz band requires a large no of antenna arrays at two sides of transmitter and receiver terminals to beam forming gains, in a way to counteract the high path loss. There are many Precoding methods existing, like Zero Forcing (ZF) method, Branch and Bound (B&B) method and Hybrid method. In the form of fully digital method it’s not possible to do with more no of antenna arrays due to hardware complexity at such ranges, while coming to purely analog also suffers the bad performance circumstances. Hence we propose a Hybrid Precoding method in Digital/Analog in the multi user scenario based on the Kalman approach. To mainly reduce the errors between transmitted data to estimated data. Simulation results validates that immense improvement and better performance is achieved compared to existing precoding methods in terms of BER and spectral efficiency.

scholarly journals Efficient Pilot Decontamination Schemes in 5G Massive MIMO Systems

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 55 ◽  
Author(s):  
Omar A. Saraereh ◽  
Imran Khan ◽  
Byung Moo Lee ◽  
Ashraf Tahat
Keyword(s):  
Massive Mimo ◽  
Communication Systems ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Path Loss ◽  
Achievable Rate ◽  
Pilot Contamination ◽  
User Grouping ◽  
Channel Conditions ◽  
Input Multiple Output

Massive Multiple-input Multiple-output (MIMO) is an emerging technology for the 5G wireless communication systems which has the potential to provide high spectral efficient and improved link reliability and accommodate large number of users. Aiming at the problem of pilot contamination in massive MIMO systems, this paper proposes two algorithms to mitigate it. The first algorithm is depending on the idea of Path Loss to perform User Grouping (PLUG) which divide the users into the center and edge user groups depending on different levels of pilot contamination. It assigns the same pilot sequences to the center users which slightly suffer from pilot contamination and assign orthogonal pilot sequences to the edge users which severely suffer from pilot contamination. It is assumed that the number of users at the edge of each cell is the same. Therefore, to overcome such limitations of PLUG algorithm, we propose an improved PLUG (IPLUG) algorithm which provides the decision parameters for user grouping and selects the number of central and edge users in each cell in a dynamic manner. Thus, the algorithm prevents the wrong division of users in good channel conditions being considered as an edge user which causes large pilot overhead, and also identifies the users with worst channel conditions and prevents the wrong division of such users from the center user group. The second algorithm for pilot decontamination utilizes the idea of pseudo-random codes in which orthogonal pilot are assigned to different cells. Such codes are deployed to get a transmission pilot by scrambling the user pilot in the cell. Since the pilot contamination is generated because different cells multiplex the same set of orthogonal pilots and the pseudo-random sequences have good cross-correlation characteristics, this paper uses this feature to improve the orthogonality of pilots between different cells. Simulation results show that the proposed algorithms can effectively improve channel estimation performance and achievable rate as compared with other schemes.

scholarly journals Machine Learning Enabled Performance Prediction Model for Massive-MIMO HetNet System

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 800
Author(s):  
Shuvabrata Bandopadhaya ◽  
Soumya Ranjan Samal ◽  
Vladimir Poulkov
Keyword(s):  
Machine Learning ◽  
Spectral Efficiency ◽  
Massive Mimo ◽  
Network Performance ◽  
Performance Metrics ◽  
Service Providers ◽  
Mimo Systems ◽  
Capital Expenditure ◽  
Base Stations ◽  
Achievable Rate

To support upcoming novel applications, fifth generation (5G) and beyond 5G (B5G) wireless networks are being propelled to deploy an ultra-dense network with an ultra-high spectral efficiency using the combination of heterogeneous network (HetNet) solutions and massive Multiple Input Multiple Output (MIMO). As the deployment of massive MIMO HetNet systems involves a high capital expenditure, network service providers need a precise performance analysis before investment. The performance of such networks is limited because of presence of inter-cell and inter-tier interferences. The conventional analytic approach to model the performance of such networks is not trivial, as the performance is a stochastic function of many network parameters. This paper proposes a machine learning (ML) approach to predict the network performance of a massive MIMO HetNet system considering a multi-cell scenario. This paper considers a two-tier network in which the base stations of each tier are equipped with massive MIMO systems working in a sub 6GHz band. The coverage probability (CP) and area spectral efficiency (ASE) are considered to be the network performance metrics that quantify the reliability and achievable rate in the network, respectively. Here, an ML model is inferred to predict the numerical values of the performance metrics for an arbitrary network configuration. In the process of practical deployments of future networks, the use of this model could be very valuable.

scholarly journals Hybrid Precoding/Combining for single-user and Multi-Usersin mm-Wave MIMO systems

2019 ◽  
Vol 9 (2S3) ◽  
pp. 134-139
Keyword(s):  
Antenna Arrays ◽  
Mimo Systems ◽  
Matching Pursuit ◽  
Bench Mark ◽  
Angle Of Arrival ◽  
Multiuser Mimo ◽  
Parallel Transmission ◽  
Performance Loss ◽  
Hybrid Precoding ◽  
Single User

mm-Wave is one of the potential 5G technology predominant at high frequency. The antenna arrays allows parallel transmission to the multiple users. Due to the constraints in hardware in mm-Wave systems,it is difficult to implement conventional multiuser MIMO precoding techniques at mm-Wave. In this paper initially Hybrid mm-Wave MIMO capacity is compared with conventional MIMOperformance, the simulation results demonstrates that the performance loss is due to assumption of the quantized angle of arrival and departures in dictionary which is very small using OMP algorithm and the capacity approaches the conventional MIMO performance. Then the Hybrid Precoding(HP)at mm-Wave is formulated as a sparse optimization problem in which the hybrid MIMO precoders and combiners are used as the measurement matrices.Here transmit precoding and combining at the receiver is considered with a limited feedback as knowledge of channel may not be practically available.Orthogonal matching Pursuit(OMP) algorithm is used for single-user case and alsoin Multi-user case using simultaneous Orthogonal matching pursuit(SOMP) algorithm. In single user case numerical results are presented which shows that the proposed algorithm approach is closer to their unconstraint performance even after considering hardware constraints. Multi-user precoding results illustrates that the proposed HP method offers higher Spectral efficiency (SE) compared to analog –only beamforming (AB) and is close tothe performance bench mark of optimal digital beamformer

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