Walsh–Hadamard Transform Based Non-Orthogonal Multiple Access (NOMA) and Interference Rejection Combining in Next-Generation HetNets

In heterogeneous networks (HetNets), non-orthogonal multiple access (NOMA) has recently been proposed for hybrid-access small-cells, promising a manifold network capacity compared to OMA. One of the major issues with the installation of a hybrid-access mechanism in small-cells is the cross-tier interference (intercell interference (ICI)) caused by the macrocell users (MUs) that are unable to establish a connection to the small-cell base station (SBS). In this paper, a joint strategy is proposed for hybrid-access small-cells using the Walsh–Hadamard transform (WHT) with NOMA and interference rejection combining (IRC) to achieve high performance gains and mitigate intercell interference (ICI), respectively. WHT is applied mathematically as an orthogonal variable spreading factor (OVSF) to achieve diversity in communication systems. When applied jointly with NOMA, it ensures better performance gains than the conventional NOMA. It reduces the bit error rate (BER) and enhances subsequent throughput performance of the system. IRC is used at the receiver side for managing the cross-tier interference caused by MUs that are unable to connect to the small-cell base station (SBS) for hybrid-access. The work considers both ideal and nonideal successive interference cancellation (SIC) conditions for NOMA. Mathematical modeling is provided for the proposed joint strategy for HetNets and the results validate it in terms of BER and subsequent user throughput performance, compared to the conventional NOMA approach.

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MEASUREMENT OF EMF EXPOSURE AROUND SMALL CELL BASE STATION SITES

Radiation Protection Dosimetry ◽

10.1093/rpd/ncy201 ◽

2018 ◽

Vol 184 (2) ◽

pp. 211-215

Author(s):

Marthinus Jacobus van Wyk ◽

Jacobus Christiaan Visser ◽

Christiaan Wynand le Roux

Keyword(s):

Geographical Area ◽

Mobile Network ◽

Base Station ◽

Small Cell ◽

Base Stations ◽

Small Cells ◽

Service Areas ◽

Exposure Levels ◽

Network Technologies ◽

Cell Base

Abstract As mobile network technologies and usage change, mobile network cells have become smaller to meet the increased demand for data throughput. Small cell base stations are frequently used as a mobile network deployment method and are predominantly installed to service areas with a high density of people and to cover a small geographical area. Various measurement programs of the electromagnetic field (EMF) exposure have been conducted around base stations in general and these results have been published. There is, however, little data available on the EMF exposure levels around small cells. A measurement program was conducted to perform EMF exposure measurements around small cell base station sites. Results are compared to the relevant safety guidelines and to available data for EMF exposure around base stations in general.

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Study of Power Control in CDMA System on the basis of optimization Technique

International Journal of Advanced Research in Computer Science and Software Engineering ◽

10.23956/ijarcsse.v7i8.38 ◽

2017 ◽

Vol 7 (8) ◽

pp. 126

Author(s):

. Geetanjli

Keyword(s):

Power Control ◽

Multiple Access ◽

Optimization Technique ◽

System Optimization ◽

Base Station ◽

Particle Swarm Algorithm ◽

Cdma System ◽

Frequency Division ◽

Cdma Systems ◽

Time Division

The power control in CDMA systems, grant numerous users to share resources of the system uniformly between each other, leading to expand capacity. With convenient power control, capacity of CDMA system is immense in contrast of frequency division multiple access (FDMA) and time division multiple access (TDMA). If power control is not achieved numerous problems such as the near-far effect will start to monopolize and consequently will reduce the capacity of the CDMA system. However, when the power control in CDMA systems is implemented, it allows numerous users to share resources of the system uniformly between themselves, leading to increased capacity For power control in CDMA system optimization algorithms i.e. genetic algorithm & particle swarm algorithm can be used which regulate a convenient power vector. These power vector or power levels are dogged at the base station and announce to mobile units to alter their transmitting power in accordance to these levels. The performances of the algorithms are inspected through both analysis and computer simulations, and compared with well-known algorithms from the literature.

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Interference Cancellation Based Spectrum Sharing for Massive MIMO Communication Systems

Sensors ◽

10.3390/s21113584 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3584

Author(s):

Milembolo Miantezila Junior ◽

Bin Guo ◽

Chenjie Zhang ◽

Xuemei Bai

Keyword(s):

Interference Cancellation ◽

Communication Systems ◽

Spectrum Sharing ◽

Null Space ◽

Base Station ◽

Base Stations ◽

Small Cells ◽

Data Traffic ◽

New Approach ◽

Lte Advanced

Cellular network operators are predicting an increase in space of more than 200 percent to carry the move and tremendous increase of total users in data traffic. The growing of investments in infrastructure such as a large number of small cells, particularly the technologies such as LTE-Advanced and 6G Technology, can assist in mitigating this challenge moderately. In this paper, we suggest a projection study in spectrum sharing of radar multi-input and multi-output, and mobile LTE multi-input multi-output communication systems near m base stations (BS). The radar multi-input multi-output and mobile LTE communication systems split different interference channels. The new approach based on radar projection signal detection has been proposed for free interference disturbance channel with radar multi-input multi-output and mobile LTE multi-input multi-output by using a new proposed interference cancellation algorithm. We chose the channel of interference with the best free channel, and the detected signal of radar was projected to null space. The goal is to remove all interferences from the radar multi-input multi-output and to cancel any disturbance sources from a chosen mobile Communication Base Station. The experimental results showed that the new approach performs very well and can optimize Spectrum Access.

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Unified Regime Controller for Optical Communication Transceiver of a Pico-Cell Base Station

2020 27th International Conference on Telecommunications (ICT) ◽

10.1109/ict49546.2020.9239458 ◽

2020 ◽

Author(s):

Aleksei Alyoshin ◽

Dmitriy Fofanov ◽

Boris Kartyshev ◽

Mikhail E. Belkin ◽

Alexander Sigov

Keyword(s):

Optical Communication ◽

Base Station ◽

Cell Base

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Study of 5G-NR-MIMO Links in the Presence of an Interferer

Electronics ◽

10.3390/electronics10060732 ◽

2021 ◽

Vol 10 (6) ◽

pp. 732

Author(s):

Avner Elgam ◽

Yael Balal ◽

Yosef Pinhasi

Keyword(s):

Mobile Networks ◽

Communication Systems ◽

Multiple Input Multiple Output ◽

Local Area ◽

Maximum Energy ◽

Base Station ◽

Small Cells ◽

Diversity Coding ◽

Shift Keying ◽

Input Multiple Output

Many communication systems are based on the Multiple Input, Multiple Output (MIMO) scheme, and Orthogonal Space–time Block Transmit diversity Coding (OSTBC), combined with Maximal Ratio Receive Combining (MRRC), to create an optimal diversity system. A system with optimal diversity fixes and optimizes the channel’s effects under multi-path and Rayleigh fading with maximum energy efficiency; however, the challenge does not end with dealing with the channel destruction of the multi-path impacts. Susceptibility to interference is a significant vulnerability in future wireless mobile networks. The 5th Generation New Radio (5G-NR) technologies bring hundreds of small cells and pieces of User Equipment (UE) per indoor or outdoor local area scenario under a specific Long Term Evolution (LTE)-based station (e-NodeB), or under 5G-NR base-station (g-NodeB). It is necessary to study issues that deal with many interference signals, and smart jammers from advanced communication equipment cause deterioration in the links between the UE, the small cells, and the NodeB. In this paper, we study and present the significant impact and performances of 2×2 Alamouti Phase-Shift Keying (PSK) modulation techniques in the presence of an interferer and a smart jammer. The destructive effects affecting the MIMO array and the advanced diversity technique without closed-loop MIMO are analyzed. The performance is evaluated in terms of Bit Error Rate (BER) vs. Signal to Interference Ratio (SIR). In addition, we proved the impairment of the orthogonal spectrum assumption mathematically.

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