scholarly journals Distributed Base Station: A Concept System for Long-Range Broadband Wireless Access

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2396
Author(s):  
Muhammed Faruk Gencel ◽  
Maryam Eslami Rasekh ◽  
Upamanyu Madhow
Keyword(s):  
Low Cost ◽  
Fold Increase ◽  
Adaptation Strategy ◽  
Base Station ◽  
Range Extension ◽  
Transmit Beamforming ◽  
Broadband Wireless ◽  
Concept System ◽  
Received Power ◽  
Rural Broadband

We propose a concept system termed distributed base station (DBS) which enables distributed transmit beamforming at large carrier wavelengths to achieve significant range extension and/or increased downlink data rate, providing a low-cost infrastructure for applications such as rural broadband. We consider a frequency division duplexed (FDD) system using feedback from the receiver to achieve the required phase coherence. At a given range, N cooperating transmitters can achieve N2-fold increase in received power compared to that for a single transmitters, and feedback-based algorithms with near-ideal performance have been prototyped. In this paper, however, we identify and address key technical issues in translating such power gains into range extension via a DBS. First, to combat the drop in per-node SNR with extended range, we design a feedback-based adaptation strategy that is suitably robust to noise. Second, to utilize available system bandwidth, we extend narrowband adaptation algorithms to wideband channels through interpolation over OFDM subcarriers. Third, we observe that the feedback channel may become a bottleneck unless sophisticated distributed reception strategies are employed, but show that acceptable performance can still be obtained with standard uplink reception if channel time variations are slow enough. We quantify system performance compactly via outage capacity analyses.

scholarly journals Physical-Layer Security Improvement with Reconfigurable Intelligent Surfaces for 6G Wireless Communication Systems

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1439
Author(s):  
Janghyuk Youn ◽  
Woong Son ◽  
Bang Chul Jung
Keyword(s):  
Wireless Communication ◽  
Physical Layer Security ◽  
Communication Systems ◽  
Low Cost ◽  
Physical Layer ◽  
Base Station ◽  
Wireless Communication Systems ◽  
Secrecy Rate ◽  
Pilot Signal ◽  
Time Division

Recently, reconfigurable intelligent surfaces (RISs) have received much interest from both academia and industry due to their flexibility and cost-effectiveness in adjusting the phase and amplitude of wireless signals with low-cost passive reflecting elements. In particular, many RIS-aided techniques have been proposed to improve both data rate and energy efficiency for 6G wireless communication systems. In this paper, we propose a novel RIS-based channel randomization (RCR) technique for improving physical-layer security (PLS) for a time-division duplex (TDD) downlink cellular wire-tap network which consists of a single base station (BS) with multiple antennas, multiple legitimate pieces of user equipment (UE), multiple eavesdroppers (EVEs), and multiple RISs. We assume that only a line-of-sight (LOS) channel exists among the BS, the RISs, and the UE due to propagation characteristics of tera-hertz (THz) spectrum bands that may be used in 6G wireless communication systems. In the proposed technique, each RIS first pseudo-randomly generates multiple reflection matrices and utilizes them for both pilot signal duration (PSD) in uplink and data transmission duration (DTD) in downlink. Then, the BS estimates wireless channels of UE with reflection matrices of all RISs and selects the UE that has the best secrecy rate for each reflection matrix generated. It is shown herein that the proposed technique outperforms the conventional techniques in terms of achievable secrecy rates.

scholarly journals Enhancement of WiMAX networks using OPNET modeler platform

2021 ◽  
Vol 23 (3) ◽  
pp. 1510
Author(s):  
Noor Nateq Alfaisaly ◽  
Suhad Qasim Naeem ◽  
Azhar Hussein Neama
Keyword(s):  
High Speed ◽  
Network Performance ◽  
Performance Metrics ◽  
Channel Model ◽  
Low Cost ◽  
Base Station ◽  
Multipath Channel ◽  
Coverage Area ◽  
Wimax Networks ◽  
Better Than

Worldwide interoperability microwave access (WiMAX) is an 802.16 wireless standard that delivers high speed, provides a data rate of 100 Mbps and a coverage area of 50 km. Voice over internet protocol (VoIP) is flexible and offers low-cost telephony for clients over IP. However, there are still many challenges that must be addressed to provide a stable and good quality voice connection over the internet. The performance of various parameters such as multipath channel model and bandwidth over the Star trajectoryWiMAX network were evaluated under a scenario consisting of four cells. Each cell contains one mobile and one base station. Network performance metrics such as throughput and MOS were used to evaluate the best performance of VoIP codecs. Performance was analyzed via OPNET program14.5. The result use of multipath channel model (disable) was better than using the model (ITU pedestrian A). The value of the throughput at 15 dB was approximately 1600 packet/sec, and at -1 dB was its value 1300 packet/se. According to data, the Multipath channel model of the disable type the value of the MOS was better than the ITU Pedestrian A type.

scholarly journals UAV-LiCAM SYSTEM DEVELOPMENT: CALIBRATION AND GEO-REFERENCING

2018 ◽  
Vol XLII-1 ◽  
pp. 107-114 ◽  
Author(s):  
C. Cortes ◽  
M. Shahbazi ◽  
P. Ménard
Keyword(s):  
Particle Filtering ◽  
System Development ◽  
Low Cost ◽  
Base Station ◽  
Dual Frequency ◽  
Body Frame ◽  
Integrated Sensor ◽  
Sensor Orientation ◽  
Wide Range ◽  
Gnss Measurements

<p><strong>Abstract.</strong> In the last decade, applications of unmanned aerial vehicles (UAVs), as remote-sensing platforms, have extensively been investigated for fine-scale mapping, modeling and monitoring of the environment. In few recent years, integration of 3D laser scanners and cameras onboard UAVs has also received considerable attention as these two sensors provide complementary spatial/spectral information of the environment. Since lidar performs range and bearing measurements in its body-frame, precise GNSS/INS data are required to directly geo-reference the lidar measurements in an object-fixed coordinate system. However, such data comes at the price of tactical-grade inertial navigation sensors enabled with dual-frequency RTK-GNSS receivers, which also necessitates having access to a base station and proper post-processing software. Therefore, such UAV systems equipped with lidar and camera (UAV-LiCam Systems) are too expensive to be accessible to a wide range of users. Hence, new solutions must be developed to eliminate the need for costly navigation sensors. In this paper, a two-fold solution is proposed based on an in-house developed, low-cost system: 1) a multi-sensor self-calibration approach for calibrating the Li-Cam system based on planar and cylindrical multi-directional features; 2) an integrated sensor orientation method for georeferencing based on unscented particle filtering which compensates for time-variant IMU errors and eliminates the need for GNSS measurements.</p>

Chipless RFID Sensor for High Voltage Condition Monitoring

2012 ◽  
pp. 304-333
Author(s):  
Emran Md Amin ◽  
Nemai Chandra Karmakar
Keyword(s):  
Condition Monitoring ◽  
High Voltage ◽  
Radio Frequency Identification ◽  
Low Cost ◽  
Base Station ◽  
Novel Approach ◽  
Frequency Identification ◽  
On Line ◽  
Passive Rfid ◽  
Passive Circuit

A novel approach for non-invasive radiometric Partial Discharge (PD) detection and localization of faulty power apparatuses in switchyards using Chipless Radio Frequency Identification (RFID) based sensor is presented. The sensor integrates temperature sensing together with PD detection to assist on-line automated condition monitoring of high voltage equipment. The sensor is a multi-resonator based passive circuit with two antennas for reception of PD signal from the source and transmission of the captured PD to the base station. The sensor captures PD signal, processes it with designated spectral signatures as identification data bits, incorporates temperature information, and retransmits the data with PD signals to the base station. Analyzing the PD signal in the base station, both the PD levels and temperature of a particular faulty source can be retrieved. The prototype sensor was designed, fabricated, and tested for performance analysis. Results verify that the sensor is capable of identifying different sources at the events of PD. The proposed low cost passive RFID based PD sensor has a major advantage over existing condition monitoring techniques due to its scalability to large substations for mass deployment.

Wireless Sensor Network for Performance Monitoring of Electrical Machine

2015 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Priyanka Ranaware ◽  
N.D. Dhoot
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Low Cost ◽  
Monitoring Network ◽  
Base Station ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Electrical Machine ◽  
Prototype System ◽  
Monitoring And Control

<p class="Default">This paper proposes a novel industrial wireless sensor network for industrial machine condition monitoring. To avoid unexpected equipment failures and obtain higher accuracy in diagnostic and prognostic for the health condition of a motor, efficient and comprehensive data collecting, monitoring, and control play an important role to improve the system more reliable and effective. A novel wireless data collection for health monitoring system of electric machine based on wireless sensor network is proposed and developed in this paper. The unique characteristics of ZigBee networks such as low power, low cost, and high flexibility make them ideal for this application. The proposed system consists of wireless sensor nodes which are organized into a monitoring network by ZigBee protocols. A base station and wireless nodes have been developed to form a prototype system. Various sensors have the capability to monitor physiological as well as environmental conditions. Therefore proposed system provides a flexible solution that makes our living spaces more intelligent.</p>

Design and Development of Low Cost Navigation and Security System for Indian Fisherman Using Adrino Nano Platform

2015 ◽  
Vol 4 (1) ◽  
pp. 28
Author(s):  
Sanket Dessai ◽  
Mahir M.M. ◽  
Mayur R. ◽  
Nilkantha Singha ◽  
Vinutha Avaradhi
Keyword(s):  
Fuel Injection ◽  
Low Cost ◽  
Base Station ◽  
Coast Guard ◽  
Security System ◽  
Injection System ◽  
Control Panel ◽  
Material Loss ◽  
Maritime Boundary ◽  
Time Stamps

<p>The fishing industry plays a major role in development of Indian economy. The recent attacks on fishermen taking place in Indo-Srilanka and Indo-Pakistan maritime boundaries have been major concerns. These attacks are primarily caused by the lack of navigation and security features during the voyage. Hence the current situation demands the implementation of precise facilities for reducing man and material loss. This project involves the design and implementation of a Low cost Navigation and Security System for Indian fishermen on Arduino Nano platform. The system developed solves the above said issues by continously tracking the location of fishing vessel and providing minimal security features. The system ensures that navigation is in safe zone within the nation’s maritime boundary and also prevents crossover. This is acheived using GPS receiver which directly links to GPS satellites for current location of the vessel. The required data fields like the latitude and longitude data along with the time stamps are extracted from the GPS samples and used for comparision for determining the exact location of the vessel. This procedure will help in detection of corner cases when the vessel is nearing or about to crossover the maritime boundary, which cannot be marked physically. It is useful for triggering conditions like enabling or disabling fuel injection system, the warning beeps and display notifications to the fishermen. Manual override facility for restarting the engine in case of crossover for limited duration is provided. The security features like authentication for the genuine operator to get access to the engine panel, the support for distress message and the storage of the exact time stamps and GPS locations after encryption in case of initiation of transmitting distress message is provided as a blackbox feature. The passcode based mechanism allows for maximum of three attempts to unlock access to control panel. The GSM modem allows for transmission of distress message to the registered base station/coast guard. The encrypted GPS samples and time stamps are stored in on-chip EEPROM memory for future reference.    <strong></strong></p>

scholarly journals A Survey on Massive MIMO Systems in Presence of Channel and Hardware Impairments

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 164 ◽  
Author(s):  
Zahra Mokhtari ◽  
Maryam Sabbaghian ◽  
Rui Dinis
Keyword(s):  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo Systems ◽  
Low Cost ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Aging Effects ◽  
Hardware Impairments ◽  
Single Carrier ◽  
Input Multiple Output

Massive multiple input multiple output (MIMO) technology is one of the promising technologies for fifth generation (5G) cellular communications. In this technology, each cell has a base station (BS) with a large number of antennas, allowing the simultaneous use of the same resources (e.g., frequency and/or time slots) by multiple users of a cell. Therefore, massive MIMO systems can bring very high spectral and power efficiencies. However, this technology faces some important issues that need to be addressed. One of these issues is the performance degradation due to hardware impairments, since low-cost RF chains need to be employed. Another issue is the channel estimation and channel aging effects, especially in fast mobility environments. In this paper we will perform a comprehensive study on these two issues considering two of the most promising candidate waveforms for massive MIMO systems: Orthogonal frequency division multiplexing (OFDM) and single-carrier frequency domain processing (SC-FDP). The studies and the results show that hardware impairments and inaccurate channel knowledge can degrade the performance of massive MIMO systems extensively. However, using suitable low complex estimation and compensation techniques and also selecting a suitable waveform can reduce these effects.

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