Propagation measurements and estimation of channel propagation models in urban environment

Wireless communication is a telecommunication technology, which enables wireless transmission between the portable devices to provide wireless access in all types of environments. In this research, the measurements and various empirical models are analysed and compared in order to find out a suitable propagation model to provide guidelines for cell planning of wireless communication systems. The measured data was taken in urban region with low vegetation and some trees at 900 MHz frequency band. Path loss models are useful planning tools, which permit the designers of cellular communication to obtain optimal levels for the base station deployment and meeting the expected service level requirements. Outcomes show that these empirical models tend to overestimate the propagation loss. As one of the key outputs, it was observed that the calculations of Weissberger model fit with the measured data in urban environment

Determination of correlation coefficients for RazakSAT received signals

RazakSAT is the second Malaysian Earth observation satellite operating with downlink frequency of 2.232 GHz (S-band). RazakSAT’s received signals had been recorded in percentage unit and the values are required be quantified in the common signal strength unit, dBm. This paper details how such has been achieved. Measurements were carried out in order to establish the correlation between the percentage values and dBm values. The campaign involved the setting-up of a terrestrial microwave link transmission comprised of a transmitter, a receiver, and relevant antennas at about 500 m displacement. The transmitted power was controlled with the use of a signal generator and the received power level was measured using a spectrum analyzer. Appropriate coefficients for the correlation had been determined. The slope coefficient, m has been derived to have the value of 0.7765 and its slope intercept coefficient, c has the value of 85.301. Using these coefficients, the received satellite signals can then be converted into dBm