scholarly journals Analisa Karakteristik Kanal HF Lintasan Jamak

2020 ◽  
Vol 11 (3) ◽  
pp. 124
Author(s):  
Rizki Nugraha Hidayat ◽  
Umaisaroh Umaisaroh ◽  
Said Attamimi
Keyword(s):  
High Frequency ◽  
Delay Spread ◽  
Power Delay Profile

Indonesia merupakan negara kepulauan terbesar di dunia. Oleh karena itu, diperlukan konsep dan perencanaan sistem komunikasi jarak jauh yang murah dan handal agar bisa terhubungnya komunikasi di wilayah kepulauan yang relatif sulit dijangkau oleh sistem kabel yang sudah terhubung saat ini. Sistem komunikasi high frequency (HF) yang beroperasi pada frekuensi 3-30 MHz. Sistem ini memanfaatkan lapisan ionosfer sebagai media transmisi gelombang radionya. Lapisan ionosfer sangat dipengaruhi oleh aktivitas matahari dan perubahan waktu sepanjang hari. Hal ini berakibat timbulnya gangguan-gangguan ionosfer yang menyebabkan kinerja sistem komunikasi HF terganggu juga kondisi dimana terdapat interferensi ketika sinyal lebih dari satu jalur pada saat ditransmisikan hal ini dinamakan multipath atau lintasan jamak. Karakteristik kanal HF menjadi hal yang sangat penting. Dengan mengetahui karakteristik kanal HF yang tepat kita dapat mencapai kinerja sistem komunikasi yang lebih baik. Perubahan kondisi lapisan ionosfer berpotensi mempengaruhi kinerja sistem komunikasi HF yang disebabkan oleh nilai delay spread. Pada penelitian ini dilakukan analisa parameter karakteristik kanal HF mengenai power delay profile dan delay spread yang dilakukan dengan uji simulasi. Berdasarkan hasil percobaan dalam kurun waktu 2 bulan. Dilakukan sebanyak 8 kali percobaan dalam 4 waktu yang berbeda. Menghasilkan nilai delay spread maksimal terjadi pada pagi hari yaitu bernilai 124,1 ms berbeda dengan sore hari yang memiliki nilai 41 ms.

scholarly journals Analysis of Non-Stationarity for 5.9 GHz Channel in Multiple Vehicle-to-Vehicle Scenarios

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3626
Author(s):  
Fang Li ◽  
Wei Chen ◽  
Yishui Shui
Keyword(s):  
Transmission Rate ◽  
Radio Channel ◽  
Vertical Direction ◽  
Statistical Characteristics ◽  
Small Scale ◽  
Delay Spread ◽  
Important Indicator ◽  
Power Delay Profile ◽  
Channel Characteristics ◽  
Vehicle To Vehicle

The vehicle-to-vehicle (V2V) radio channel is non-stationary due to the rapid movement of vehicles. However, the stationarity of the V2V channels is an important indicator of the V2V channel characteristics. Therefore, we analyzed the non-stationarity of V2V radio channels using the local region of stationarity (LRS). We selected seven scenarios, including three directions of travel, i.e., in the same, vertical, and opposite directions, and different speeds and environments in a similar driving direction. The power delay profile (PDP) and LRS were estimated from the measured channel impulse responses. The results show that the most important influences on the stationary times are the direction and the speed of the vehicles. The average stationary times for driving in the same direction range from 0.3207 to 1.9419 s, the average stationary times for driving in the vertical direction are 0.0359–0.1348 s, and those for driving in the opposite direction are 0.0041–0.0103 s. These results are meaningful for the analysis of the statistical characteristics of the V2V channel, such as the delay spread and Doppler spread. Small-scale fading based on the stationary times affects the quality of signals transmitted in the V2V channel, including the information transmission rate and the information error code rate.

scholarly journals PHY, MAC, and RLC Layer Based Estimation of Optimal Cyclic Prefix Length

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4796
Author(s):  
Adriana Lipovac ◽  
Vlatko Lipovac ◽  
Borivoj Modlic
Keyword(s):  
Error Recovery ◽  
Cyclic Prefix ◽  
Closed Form Expression ◽  
Delay Spread ◽  
Radio Link ◽  
Medium Access ◽  
Power Delay Profile ◽  
Rms Delay Spread ◽  
Industry Standard ◽  
New Radio

This work is motivated by growing evidence that the standard Cyclic Prefix (CP) length, adopted in the Long Term Evolution (LTE) physical layer (PHY) specifications, is oversized in propagation environments ranging from indoor to typical urban. Although this ostensibly seems to be addressed by 5G New Radio (NR) numerology, its scalable CP length reduction is proportionally tracked by the OFDM symbol length, which preserves the relative CP overhead of LTE. Furthermore, some simple means to optimize fixed or introduce adaptive CP length arose from either simulations or models taking into account only the bit-oriented PHY transmission performance. On the contrary, in the novel crosslayer analytical model proposed here, the closed-form expression for the optimal CP length is derived such as to minimize the effective average codeblock length, by also considering the error recovery retransmissions through the layers above PHY—the Medium Access Control (MAC) and the Radio Link Control (RLC), in particular. It turns out that, for given protective coding, the optimal CP length is determined by the appropriate rms delay spread of the channel power delay profile part remaining outside the CP span. The optimal CP length values are found to be significantly lower than the corresponding industry-standard ones, which unveils the potential for improving the net throughput.

scholarly journals NLOS Path Loss Model for Low-Height Antenna Links in High-Rise Urban Street Grid Environments

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Juyul Lee ◽  
Myung-Don Kim ◽  
Hyun Kyu Chung ◽  
Jinup Kim
Keyword(s):  
Path Loss ◽  
Field Measurements ◽  
Propagation Path ◽  
Delay Spread ◽  
Communication Link ◽  
Channel Measurements ◽  
Loss Model ◽  
Path Loss Model ◽  
Power Delay Profile ◽  
High Rise

This paper presents a NLOS (non-line-of-sight) path loss model for low-height antenna links in rectangular street grids to account for typical D2D (device-to-device) communication link situations in high-rise urban outdoor environments. From wideband propagation channel measurements collected in Seoul City at 3.7 GHz, we observed distinctive power delay profile behaviors between 1-Turn and 2-Turn NLOS links: the 2-Turn NLOS has a wider delay spread. This can be explained by employing the idea that the 2-Turn NLOS has multiple propagation paths along the various street roads from TX to RX, whereas the 1-Turn NLOS has a single dominant propagation path from TX to RX. Considering this, we develop a path loss model encompassing 1-Turn and 2-Turn NLOS links with separate scattering and diffraction parameters for the first and the second corners, based on the Uniform Geometrical Theory of Diffraction. In addition, we consider the effect of building heights on path loss by incorporating an adjustable “waveguide effect” parameter; that is, higher building alleys provide better propagation environments. When compared with field measurements, the predictions are in agreement.

scholarly journals Statistical Analysis of 5G Channel Propagation using MIMO and Massive MIMO Technologies

2021 ◽  
Vol 11 (4) ◽  
pp. 7417-7423
Author(s):  
Z. A. Shamsan
Keyword(s):  
Antenna Arrays ◽  
Massive Mimo ◽  
Multiple Input Multiple Output ◽  
Small Scale ◽  
Delay Spread ◽  
Band Frequency ◽  
Power Delay Profile ◽  
Mimo Antenna ◽  
Rms Delay Spread ◽  
Path Lengths

Multiple Input Multiple Output (MIMO) and massive MIMO technologies play a significant role in mitigating five generation (5G) channel propagation impairments. These impairments increase as frequency increases, and they become worse at millimeter-waves (mmWaves). They include difficulties of material penetration, Line-of-Sight (LoS) inflexibility, small cell coverage, weather circumstances, etc. This paper simulates the 5G channel at the E-band frequency using the Monte Carlo approach-based NYUSIM tool. The urban microcell (UMi) is the communication environment of this simulation. Both MIMO and massive MIMO use uniformly spaced rectangular antenna arrays (URA). This study investigates the effects of MIMO and massive MIMO on LOS and Non-LOS (NLOS) environments. The simulations considered directional and omnidirectional antennas, the Power Delay Profile (PDP), Root Mean Square (RMS) delay spread, and small-scale PDP for both LOS and NLOS environments. As expected, the wide variety of the results showed that the massive MIMO antenna outperforms the MIMO antenna, especially in terms of the signal power received at the end-user and for longer path lengths.

scholarly journals Statistical Characteristics of Measured 3-Dimensional MIMO Channel for Outdoor-to-Indoor Scenario in China and New Zealand

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yawei Yu ◽  
Jianhua Zhang ◽  
Mansoor Shafi ◽  
Min Zhang ◽  
Jawad Mirza
Keyword(s):  
New Zealand ◽  
Channel Model ◽  
Elevation Angle ◽  
Statistical Characteristics ◽  
Mimo Channel ◽  
Delay Spread ◽  
Angle Of Arrival ◽  
Power Delay Profile ◽  
3 Dimensional ◽  
Rms Delay Spread

The 3-dimensional (3D) channel model gives a better understanding of statistical characteristics for practical channels than the 2-dimensional (2D) channel model, by taking the elevation domain into consideration. As different organizations and researchers have agreed to a standard 3D channel model, we attempt to measure the 3D channel and determine the parameters of the standard model. In this paper, we present the statistical propagation results of the 3D multiple-input and multiple-output (MIMO) channel measurement campaign performed in China and New Zealand (NZ). The measurements are done for an outdoor-to-indoor (O2I) urban scenario. The dense indoor terminals at different floors in a building form a typical 3D propagation environment. The key parameters of the channel are estimated from the measured channel impulse response (CIR) using the spatial-alternating generalized expectation-maximization (SAGE) algorithm. Till now there is abundant research performed on the azimuth domain; this paper mainly considers the statistical characteristics of the elevation domain. A statistical analysis of 3D MIMO channel results for both China and NZ measurements is presented for the following parameters: power delay profile (PDP), root mean square (rms), delay spread (DS), elevation angle-of-arrival (EAoA) distribution, elevation angle-of-departure (EAoD) distribution, elevation angular spread (AS), and cross-polarization discrimination (XPD).

scholarly journals Indoor Corridor Wideband Radio Propagation Measurements and Channel Models for 5G Millimeter Wave Wireless Communications at 19 GHz, 28 GHz, and 38 GHz Bands

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Ahmed M. Al-samman ◽  
Tharek Abd Rahman ◽  
Marwan Hadri Azmi
Keyword(s):  
Millimeter Wave ◽  
Free Space ◽  
Path Loss ◽  
Delay Spread ◽  
Angle Of Arrival ◽  
Microwave Band ◽  
Power Delay Profile ◽  
Rms Delay Spread ◽  
Path Loss Exponent ◽  
Line Slope

This paper presents millimeter wave (mmWave) measurements in an indoor environment. The high demands for the future applications in the 5G system require more capacity. In the microwave band below 6 GHz, most of the available bands are occupied; hence, the microwave band above 6 GHz and mmWave band can be used for the 5G system to cover the bandwidth required for all 5G applications. In this paper, the propagation characteristics at three different bands above 6 GHz (19, 28, and 38 GHz) are investigated in an indoor corridor environment for line of sight (LOS) and non-LOS (NLOS) scenarios. Five different path loss models are studied for this environment, namely, close-in (CI) free space path loss, floating-intercept (FI), frequency attenuation (FA) path loss, alpha-beta-gamma (ABG), and close-in free space reference distance with frequency weighting (CIF) models. Important statistical properties, such as power delay profile (PDP), root mean square (RMS) delay spread, and azimuth angle spread, are obtained and compared for different bands. The results for the path loss model found that the path loss exponent (PLE) and line slope values for all models are less than the free space path loss exponent of 2. The RMS delay spread for all bands is low for the LOS scenario, and only the directed path is contributed in some spatial locations. For the NLOS scenario, the angle of arrival (AOA) is extensively investigated, and the results indicated that the channel propagation for 5G using high directional antenna should be used in the beamforming technique to receive the signal and collect all multipath components from different angles in a particular mobile location.

scholarly journals Measurement and Statistical Analysis of Distinguishable Multipaths in Underground Tunnels

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Junchang Sun ◽  
Shuai Ma ◽  
Hui Zhou ◽  
Chun Du ◽  
Shiyin Li
Keyword(s):  
Signal To Noise Ratio ◽  
Correlation Method ◽  
Signal Propagation ◽  
Line Of Sight ◽  
Support Vector ◽  
Delay Spread ◽  
Svm Classifier ◽  
Average Delay ◽  
Power Delay Profile ◽  
The Impact

Compared with the line-of-sight (LOS) condition, the multipath effect is more serious in the non-line-of-sight (NLOS) condition. Therefore, the LOS and NLOS identification is necessary for the multipath analysis of signal propagation. The commonly used method is the support vector machine (SVM) method with high computational complexity. To tackle this problem, this paper adopts the SVM classifier based on fewer selected features of the normalized power delay profile (PDP). Therein, the PDP can be obtained using the sliding correlation method. The results show that the SVM-based classifier can achieve high accuracy on LOS and NLOS identification. We then analyze the impact of the signal-to-noise ratio (SNR) and transmitting-receiving (Tx-to-Rx) distance on distinguishable multipaths under LOS and NLOS conditions. According to statistical measurement results, a function of distinguishable multipath numbers is established. Finally, we investigate the multipath power and delay parameters of average delay spread and root mean square (RMS) delay spread based on multipath results. The outcomes of this paper provide a useful support for analyzing signal propagation characteristics.

scholarly journals Experimental Characterization of LTE Wireless Links in High-Speed Trains

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
Tomás Domínguez-Bolaño ◽  
José Rodríguez-Piñeiro ◽  
José A. García-Naya ◽  
Luis Castedo
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Path Loss ◽  
Delay Spread ◽  
Power Delay Profile ◽  
Power Spectral ◽  
Railway Infrastructure ◽  
High Speed Trains ◽  
Doppler Power ◽  
The One

Multimedia and data-based services experienced a nonstopping growth over the last few years. People are continuously on the move using devices to access multimedia contents or other data-based services. Due to this, railway companies are showing a great interest in deploying broadband mobile wireless networks in high-speed-trains with the aim of supporting both passenger services provisioning as well as automatic train control and signaling. Nowadays, the most widely used technology for communications between trains and the railway infrastructure is GSM for Railways (GSM-R); however, it has limited capabilities to support such advanced services. Due to its success in the mass market, Long Term Evolution (LTE) seems to be the best candidate to substitute GSM-R. In this paper, we experimentally characterize the downlink between an LTE Evolved NodeB (eNodeB) and a high-speed train in a commercial high-speed line. We consider two links: the one between the eNodeB and the antennas placed outdoors on the train roof, and the direct link between the eNodeB and a receiver inside the train. Such a characterization consists in assessing the path loss, the Signal to Noise Ratio, the K-Factor, the Power Delay Profile, the delay spread, and the Doppler Power Spectral Density.

Sign in / Sign up

Export Citation Format

Share Document