Propagation-path losses characterization for 900 MHz cellular communications in Dhaka city

Abstract

In cellular communication system, usually we use the propagation path-losses to characterize the quality of the cellular communication within the coverage area The factor can also be utilized in the cellular base station design e.g. the distance between the base stations, the optimum power of transmitter, the height and gain of antenna used in 11base station. There are many researchers, mainly in the USA and Japan, proposing models to characterize the propagation path-losses ranging from a simple to a complicated equation. These relationships are developed incorporating all the relevant factors such as the mo4ulating.Jn,quency, the !leigh! of transmitting and receiving antenna, the h~, the number. Of obstructions and building in the area, etc. This research work presents the propagation modeling of a 900 MHz cellular mobile system for determining design parameters of its coverage areas. The conventional model proposed by Lee and Hata has modified for appropriate use in Dhaka City area. Having measured the field strengths at 56 locations in Dhaka City, it is found that the average propagation-path loss at I mile, is 80.2 dBm, and the slope of the path loss, is 29.8 dB/dec. The measurements are based on a reference regarding the antenna heights of the base station and receiving station at 30 and 3 meters, and the antenna gains of the base station and receiving station at 6dBd and 0dBd respectively. Results obtained are compared with those of predicted by Grameen Phone. Also the results are compared with those of Tokyo, New York, & Bangkok. A cell planning scheme of Dhaka city is proposed for frequency spectrum of 5 MHz as allocated to Grameen Phone. Using the most efficient reuse schemes, the channels are distributed among 34 cells that covers the most densely populated portion of Dhaka city