Hassan Dao

Preliminary analysis of Ku-band rain fade data for earth-to-satellite path measured in Malaysia

The dynamic characteristics of rain fade slope are one of the important factors in the determination of the earth-to-space communication system availability. It is also useful in the design of the fade countermeasures. This paper investigates the rain fade slope which is one of the main features of fade dynamics with 0.1s, 0.5s, 1s, 2s, 5s and 10s sampling time intervals. The rain fade slope model proposed by the ITU-R was compared with the corresponding statistics obtained from rain attenuation data measured using MEASAT3 downlink at Ku-band in Malaysia during May 2010 - June 2011. Significant discrepancies have been observed between the measured fade slope data and that predicted by the ITU-R prediction model with different sampling time interval.

Rain attenuation analysis using synthetic storm technique in Malaysia

Generated rain attenuation time series plays an important role for investigating the rain fade characteristics in the lack of real fade measurements. A suitable conversion technique can be applied to measured rain rate time series to produce rain attenuation data and be utilized to understand the rain fade characteristics. This paper focuses on applicability of synthetic storm technique (SST) to convert measured rain rate data to rain attenuation time series. Its performance is assessed for time series generation over a tropical location Kuala Lumpur, in Malaysia. From preliminary analysis, it is found that SST gives satisfactory results to estimate the rain attenuation time series from the rain rate measurements over this region.

Analysis of rain fade duration over satellite-earth path at Ku-Band in tropics

Statistical analysis is fundamental information for system engineer to design and plan satellite communication link. Fade duration is one aspect of fade dynamics that contributes designing of fade mitigation techniques (FMT). This paper presents statistical analysis on fade duration on high elevation angle (77.4°) in Ku-band carried out in Kuala Lumpur, Malaysia with 12 months duration statistics.

Rain fade slope analysis for terrestrial microwave link in Malaysia

This paper analyzes fade slope during raining events based on measured data on terrestrial microwave link in Kuala Lumpur operating at 15GHz and 23 GHz. Fade slope is examined on a statistical basis for the two sites. The annual statistics of fade slope are presented and compared to Van de Kamp model which is recommended by ITU-R.

Fade dynamics review of microwave signals on earth-space paths at Ku-band

An investigation is carried out on the dynamic factors that can cause fading in Earth-space link signals. A comparison is made between the ITU-R recommended model and the measurements, carried out in a number of countries. A fade countering measure algorithm is presented. The measure may be essential for the efficient design of a microwave Earth-space links, especially for the dynamic behaviour of fading. The proposed model aims at considering tropical climatic regions, since most of the previous studies are concerned with temperate regions, such as Europe, American etc.

Analysis of Synthetic Storm Technique Based on Ku-Band Satellite Beacon Measurements in Malaysia

Most of the existing rain attenuation prediction models were proposed based on measurements taken in temperate climates. These models are found not accurate in tropical regions and were thus modified in order for such models to be applied in tropical regions. Synthetic Storm Technique (SST) is one of the most reliable methods to estimate rain attenuation time series in Europe. However, due to the lack of measured data in the tropical regions of the world, the above-mentioned method is yet to be validated for those regions. This paper aims to investigate SST validity in Malaysia by focusing on both rain events and the overall statistical behavior. Its performance is assessed based on concurrent measurement of Ku-band satellite beacon and rain rate over University of Science Malaysia (USM) campus at Tronoh. Preliminary analysis shows that SST is capable of providing details of time-series of many rain events to reflect the dynamics of rain fade. However, it is unable to predict the entire range of rain intensity.

Scintillation measurement on Ku-band satellite path in tropical climate

Scintillation data was collected in Kuala Lumpur, Malaysia for one year measurement. The data were obtained from MEASAT3 satellite operating at Ku-band with elevation angle of 77.4 . In this paper, scintillation statistics are analysed in dry (non-rain) condition. The scintillation distributions are represented scintillation intensity and amplitude by monthly, seasonal, worst-month and annual distributions. Probability density function (PDF) of scintillation intensity correspondingly agrees to Generalize Extreme Value (GEV) fit. In addition, model validation to the measured data is also provided.

Analysis of long term tropospheric scintillation from Ku-band satellite link in tropical climate

Scintillation is the rapid signal fluctuations of amplitude and phase of a radiowave which can cause signal loss in the transmission path with time. Other propagation factors that contribute to the signal fluctuations must be omitted before using the raw data for scintillation studies. Scintillation occurs continuously whether it is under clear sky condition or raining. Therefore, during raining event, the scintillation data will be accompanied by the signal level attenuation caused by the rain. Hence, attention must be given when analyzing scintillation data during raining event. This paper presents the data analysis of the tropospheric scintillation for earth to satellite link at Ku-band. Eight months (May 2011 till December 2011) data were collected and were analyzed to see the effect of tropospheric scintillation during morning, midday, evening and midnight. In this paper, the scintillation data were analyzed during clear sky condition. Any spurious signals caused by other propagation factors were eliminated accordingly. The experimental data were collected using 2.4 m dish antenna through MEASAT 3 at 10.982 GHz. The elevation angle of the dish antenna is stationed at 77.5°. The findings show that scintillation amplitude during midday is highest if compared to morning, evening and midnight. During midnight, the scintillation amplitudes drop significantly.

Effect of frequency on fade slope based on rain attenuation data measured in malaysia

Wave propagation at higher frequencies is highly influenced by rain. The measured rain attenuation data was collected from January 1999 to April 2000 at 15, 23 26, and 38 GHz frequencies for terrestrial microwave links in Malaysia. This research investigated the effects of frequency on the fade slope. The fade slope was analyzed using the measured data and it is found that the distribution for the fade slope is similar for all four frequencies and independent of frequencies.

Fade dynamics analysis for terrestrial microwave links

Terrestrial microwave system is the backbone line for mobile communication industry. In tropical region particularly in Malaysia, rain attenuation is the major constraint for implementing microwave system above 10 GHz. This paper presents statistical analysis of the dynamics of rain attenuation such as fade duration and fade slope. To prepare these statistics, rain attenuation data were obtained in Malaysia at frequencies 15 and 23 GHz for the period between January 1999 to April 2000. Fade duration statistics will be compiled for attenuation exceeding different attenuation levels (fade thresholds). The fade slope statistics will be analyzed by calculating the conditional probability density function (PDF) of fade slope for the measured data. The comparison of ITU-R models and the measured data will be investigated and analysed.