The Research on the Police Adaptive Wireless Communications

2013 ◽  
Vol 850-851 ◽  
pp. 549-552
Author(s):  
Chuan Sheng Zhao
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
Channel Model ◽  
Model Simulation ◽  
Excellent Performance ◽  
Adaptive Equalizers ◽  
Time Invariant

Most Current researches about the police adaptive wireless communication are concentrated on the area of the time-invariant channel model, which is not fit to the requirement of police application. This paper designed an time-variant ISI channel model, according to the characteristics of police wireless communication. And analyzed the performance of the LMS and the RLS algorithms in DFE structure adaptive equalizers, under the time-variant ISI channel model. Simulation shows that the designed adaptive equalizers obtained excellent performance.

scholarly journals Empirical Path Loss Channel Characterization Based on Air-to-Air Ground Reflection Channel Modeling for UAV-Enabled Wireless Communications

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jatuporn Supramongkonset ◽  
Sarun Duangsuwan ◽  
Myo Myint Maw ◽  
Sathaporn Promwong
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
Channel Model ◽  
Measurement Data ◽  
Path Loss ◽  
Channel Modeling ◽  
Channel Characterization ◽  
Distance Model ◽  
Aerial Vehicle ◽  
The Impact

The purpose of this work was to investigate the air-to-air channel model (A2A-CM) for unmanned aerial vehicle- (UAV-) enabled wireless communications. Specifically, a low-altitude small UAV needs to characterize the propagation mechanisms from ground reflection. In this paper, the empirical path loss channel characterizations of A2A ground reflection CM based on different scenarios were presented by comparing the wireless communication modules for UAVs. Two types of wireless communication modules both WiFi 2.4 GHz and LoRa 868 MHz frequency were deployed to study the path loss channel characterization between Tx-UAV and Rx-UAV. To investigate the path loss, three types of experimental channel models, such as CM1 grass floor, CM2 soil floor, and CM3 rubber floor, were considered under the ground reflection condition. The analytical A2A Two-Ray (A2AT-R) model and the modified Log-Distance model were simulated to compare the correlation with the measurement data. The measurement results in the CM3 rubber floor scenario showed the impact from the ground reflection at 1 m to 3 m Rx-UAV altitudes both 2.4 GHz and 868 MHz which was converged to the A2AT-R model and related to the modified Log-Distance model above 3 m. It clear that there is no ground reflection effect from the CM1 grass floor and CM2 soil floor. This work showed that the analytical A2AT-R model and the modified Log-Distance model can deploy to model the path loss of A2A-CM by using WiFi and LoRa wireless modules.

scholarly journals Characterizing the Impact of Doppler Effects on Body-Centric LoRa Links with SDR

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4049
Author(s):  
Thomas Ameloot ◽  
Marc Moeneclaey ◽  
Patrick Van Van Torre ◽  
Hendrik Rogier
Keyword(s):  
Wireless Communication ◽  
Low Power ◽  
Multipath Fading ◽  
Doppler Spread ◽  
Excellent Performance ◽  
Wireless Applications ◽  
Doppler Shifts ◽  
Doppler Effects ◽  
The Impact ◽  
Measurement Campaigns

Long-range, low-power wireless technologies such as LoRa have been shown to exhibit excellent performance when applied in body-centric wireless applications. However, the robustness of LoRa technology to Doppler spread has recently been called into question by a number of researchers. This paper evaluates the impact of static and dynamic Doppler shifts on a simulated LoRa symbol detector and two types of simulated LoRa receivers. The results are interpreted specifically for body-centric applications and confirm that, in most application environments, pure Doppler effects are unlikely to severely disrupt wireless communication, confirming previous research, which stated that the link deteriorations observed in a number of practical LoRa measurement campaigns would mainly be caused by multipath fading effects. Yet, dynamic Doppler shifts, which occur as a result of the relative acceleration between communicating nodes, are also shown to contribute to link degradation. This is especially so for higher LoRa spreading factors and larger packet sizes.

scholarly journals Dual-Branch Pre-Distorted Enhanced ADO-OFDM for Full-Duplex Underwater Optical Wireless Communication System

Photonics ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 368
Author(s):  
Zixian Wei ◽  
Yibin Li ◽  
Zhaoming Wang ◽  
Junbin Fang ◽  
Hongyan Fu
Keyword(s):  
Wireless Communication ◽  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Channel Model ◽  
Full Duplex ◽  
Optical Channel ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Hardware Complexity ◽  
Double Gamma Function

In this paper, dual-branch pre-distorted enhanced asymmetrically clipped direct current (DC) biased optical orthogonal frequency division multiplexing (PEADO-OFDM) for underwater optical wireless communication (UOWC) is firstly proposed and simulated. The performances of PEADO-OFDM on the underwater optical channel model (UOCM) are analyzed and further compared with the typical ADO-OFDM. Using the Monte Carlo method for the modeling of UOCM, we adopt a double-gamma function to represent three different water qualities including clear, coastal and harbor waters. The full-duplex architecture enables the removal of Hermitian symmetry (HS) from conventional optical OFDM and can increase the spectral efficiency at the cost of hardware complexity. A new PEADO-OFDM transmitter is also proposed to reduce the complexity of the transmitter. The simulation results exhibit that our proposed dual-branch PEADO-OFDM scheme outperforms the typical ADO-OFDM scheme in spectral efficiency, bit error rate (BER) and stability over the underwater channels of three different water qualities.

scholarly journals Three-Dimensional MIMO Channel Model with High-Mobility Wireless Communication Systems Using Leaky Coaxial Cable in Rectangular Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Kai Zhang ◽  
Fangqi Zhang ◽  
Guoxin Zheng ◽  
Lei Cang
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Channel Model ◽  
Mimo System ◽  
Three Dimensional ◽  
High Mobility ◽  
Coaxial Cable ◽  
Mimo Channel ◽  
Wireless Communication Systems ◽  
Rectangular Tunnel

With the rapid development of high-mobility wireless communication systems, e.g., high-speed train (HST) and metro wireless communication systems, more and more attention has been paid to the wireless communication technology in tunnel-like scenarios. In this paper, we propose a three-dimensional (3D) nonstationary multiple-input multiple-output (MIMO) channel model with high-mobility wireless communication systems using leaky coaxial cable (LCX) inside a rectangular tunnel over the 1.8 GHz band. Taking into account single-bounce scattering under line-of-sight (LoS) and non-line-of-sight (NLoS) propagations condition, the analytical expressions of the channel impulse response (CIR) and temporal correlation function (T-CF) are derived. In the proposed channel model, it is assumed that a large number of scatterers are randomly distributed on the sidewall of the tunnel and the roof of the tunnel. We analyze the impact of various model parameters, including LCX spacing, time separation, movement velocity of Rx, and K-factor, on the T-CF of the MIMO channel model. For HST, the results of some further studies on the maximum speed of 360 km/h are given. By comparing the T-CF between the dipole MIMO system and the LCX-MIMO system, we can see that the performance of the LCX-MIMO system is better than that of the dipole MIMO system.

scholarly journals Omnidirectional Microstrip Patch Antenna for 2.4 GHz Wireless Communications

2021 ◽  
Vol 2114 (1) ◽  
pp. 012051
Author(s):  
Alaa M. Abdulhussein ◽  
Ali H. Khidhi ◽  
Ahmed A. Naser
Keyword(s):  
Computer Simulation ◽  
Wireless Communications ◽  
Wireless Communication ◽  
Patch Antenna ◽  
Communication Systems ◽  
Return Loss ◽  
Microstrip Patch Antenna ◽  
Wireless Communication Systems ◽  
Microstrip Patch ◽  
Operating Bandwidth

Abstract Antenna studies on various wireless communication systems have been carried out by many academics. In this research, the omnidirectional microstrip patch antenna (MPA) is proposed, manufactured, and tested. The operating bandwidth of the antenna is quite suitable for the different applications. The proposed antenna fabricated on the flame retardant (FR-4) substrate with a volume of 75.85 × 57.23 × 1.59 mm3. Computer simulation technology (CST) studio used to design and simulate. Experimental results show that the return loss (RL), bandwidth (BW), voltage standing wave ratio (VSWR) and input impedance (Zin ) are -25.26 dB, 61 MHz, 1.12 and 54.46 Ω, respectively. The antenna operates at 2.42 GHz (from 2.39 to 2.45 GHz), which has good performance in the Wi-Fi, Bluetooth, and ZigBee communications.

scholarly journals Microstrip patch antenna with metamaterial using superstrate technique for wireless communication

2021 ◽  
Vol 10 (4) ◽  
pp. 2055-2061
Author(s):  
Rasha Mahdi Salih ◽  
Ali Khalid Jassim
Keyword(s):  
Wireless Communications ◽  
Reflection Coefficient ◽  
Wireless Communication ◽  
Patch Antenna ◽  
Relative Permittivity ◽  
Microstrip Antenna ◽  
Microstrip Patch Antenna ◽  
Antenna Gain ◽  
Microstrip Patch ◽  
Antenna Performance

This work builds a metamaterial (MTM) superstrate loaded on a patch of microstrip antenna for wireless communications. The MTM superstrate is made up of four G-shaped resonators on FR-4 substrate with a relative permittivity of 4.4 and has a total area of (8×16) mm2, and is higher than the patch. The MTM superstrate increases antenna gain while also raising the input reflection coefficient. When it is 9 mm above the patch, the gain increased from 3.28 dB to 6.02 dB, and when it is 7 mm above the patch, the input reflection coefficient was enhanced from -31.217 dB to -45.8 dB. When the MTM superstrate loaded antenna was compared to the traditional unloaded antenna, it was discovered that metamaterials have a lot of potential for improving antenna performance.

Global Competition and Cooperation in Standardization of Wireless Communications

2001 ◽  
pp. 108-128
Author(s):  
Zixiang (Alex) Tan
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
21St Century ◽  
Communication System ◽  
Global Competition ◽  
Wireless Communication System ◽  
Competition And Cooperation ◽  
Cooperation And Competition ◽  
The World ◽  
The Status

One of the challenges as well as opportunities for the success of wireless communication in the 21st century is the standardization that, in a simplified term, defines how specific technologies are used in a particular wireless communication system. Standardization goes beyond a technical decision made by engineers. This chapter first examines the history and the status of standardization in wireless communications in the world. Global cooperation and competition among different standards are then examined. Finally, the chapter analyzes ITU’s efforts on the 3G standardization that aim to bring harmony among the world’s wireless communication developers and providers.

Cognitive Wireless Communications – A paradigm shift in dealing with radio resources as a prerequisite for the wireless network of the future – An overview on the topic of cognitive wireless technologies

Frequenz ◽  
2016 ◽  
Vol 70 (7-8) ◽  
Author(s):  
Thomas Haustein ◽  
Slawomir Stanczak ◽  
Adam Wolisz ◽  
Friedrich Jondral ◽  
Hans Schotten ◽  
...  
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
Mobile Network ◽  
Radio Spectrum ◽  
Wireless Channel ◽  
Radio Communications ◽  
Communications Systems ◽  
Starting Point ◽  
The Status ◽  
Wireless Communications Systems

AbstractWireless radio communications systems form the basis for mobile network connections in the digital society. A limited amount of radio spectrum and a spatially densified use of wireless communications systems require a resource-efficient use of the spectrum. Mechanisms of cognitive radio may hold the key to a more efficient use of the available spectrum under consideration of quality of service requirements. These mechanisms take advantage of location-specific knowledge of the wireless channel occupation in the dimensions of frequency, time, location and direction in space and therefore enable co-existent and reliable wireless communication. The authors give an introduction to the status of cognitive wireless communication technology, which represents the starting point of a series of research projects promoted by BMBF during 2012–2014.

scholarly journals A Non-Stationary IMT-Advanced MIMO Channel Model for High-Mobility Wireless Communication Systems

2017 ◽  
Vol 16 (4) ◽  
pp. 2057-2068 ◽  
Author(s):  
Ammar Ghazal ◽  
Yi Yuan ◽  
Cheng-Xiang Wang ◽  
Yan Zhang ◽  
Qi Yao ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Channel Model ◽  
High Mobility ◽  
Mimo Channel ◽  
Wireless Communication Systems
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