• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.2
• /
• pp.223-234
• /
• 2014

This paper describes the analysis results of channel characteristics in the operating area of satellite OTM(On-The-Move) terminal. The communication channel between the Koreasat-5 and OTM terminal on a test car is measured and recorded from Daejeon to Daecheon, using the downlink frequency of around 20 GHz. And the measurement data are divided into two classes ; highway environment and national road environment, and then are statistically analyzed. The statistical evaluation of satellite channel is conducted by using probability density function and Markov model and then presents average connection duration(ACD), average fade duration( AFD), and level crossing rate(LCR) of highway environment and national road environment. Finally the statistics data of the two environments are compared with each other.

• ETRI Journal
• /
• v.45 no.5
• /
• pp.768-780
• /
• 2023

The application of unmanned aerial vehicles (UAVs) has recently attracted considerable interest in various areas. A three-dimensional multiple-input multiple-output concentric two-hemisphere model is proposed to characterize the scattering environment around a vehicle in an urban UAV-to-vehicle communication scenario. Multipath components of the model consisted of lineof-sight and single-bounced components. This study focused on the key parameters that determine the scatterer distribution. A time-variant process was used to analyze the nonstationarity of the proposed model. Vital statistical properties, such as the space-time-frequency correlation function, Doppler power spectral density, level-crossing rate, average fade duration, and channel capacity, were derived and analyzed. The results indicated that with an increase in the maximum scatter radius, the time correlation and level-crossing rate decreased, the frequency correlation function had a faster downward trend, and average fade duration increased. In addition, with the increase of concentration parameter, the time correlation, space correlation, and level-crossing rate increased, average fade duration decreased, and Doppler power spectral density became flatter. The proposed model was compared with current geometry-based stochastic models (GBSMs) and showed good consistency. In addition, we verified the nonstationarity in the temporal and spatial domains of the proposed model. These conclusions can be used as references in the design of more reasonable communication systems.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.17 no.5
• /
• pp.620-628
• /
• 2014

This paper describes the analysis results of channel characteristics in the operating area of satellite OTM (On-The-Move) terminal. The communication channel between the Koreasat-5 and OTM terminal on a test car was measured and recorded in downtown of Daejeon, using the received beacon signal of around 20 GHz. And the measurement data were statistically analyzed and then compared with highway and national road environments. The statistical evaluation of satellite channel was conducted by using probability density function and Markov model and then presented average connection duration(ACD), average fade duration(AFD), and level crossing rate(LCR) of downtown environment.

• ETRI Journal
• /
• v.35 no.4
• /
• pp.722-725
• /
• 2013

In this letter, a wireless communication system with microdiversity and macrodiversity reception in gamma-shadowed Rician fading channels is considered. Exact and rapidly converging infinite-series expressions for the average level crossing rate and average fade duration at the output of the system are provided. Numerical results are presented graphically to illustrate the proposed mathematical analysis and to examine the effects of the system's parameters on the quantities considered.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.589-593
• /
• 2003

Narrowband and wideband characterizations of radio propagation channels in tunnel environments are investigated by using ray tracing techniques. For a rectangular straight tunnel and a rectangular curved tunnel, received power is simulated when the receiver moves away from the transmitter. The fast fading statistics of the narrowband propagation are analyzed in terms of cumulative distribution function, level crossing rate and average fade duration. The tunnel wideband radio propagation channel is characterized in terms of mean excess delay and rms delay spread.