FIELD ASSESSMENT OF POWER LINK BUDGET ACCURACY IN A RESIDENTIAL FTTH GPON DEPLOYMENT

Abstract

Fiber to the Home (FTTH) based on Gigabit Passive Optical Network (GPON) is widely used for residential broadband access because of its high bandwidth capacity, scalability, and efficient use of passive optical infrastructure. During FTTH network planning, Power Link Budget (PLB) analysis is commonly applied to estimate cumulative optical losses and received optical power. However, differences may occur between theoretical PLB calculations and actual field measurements due to practical deployment conditions. This study assesses the consistency of PLB predictions using field measurements from a residential FTTH GPON deployment. Measurements were conducted at two Fiber Access Terminal (FAT) points using an Optical Power Meter, with the evaluated network employing cascaded 1:4 and 1:8 passive optical splitters. Theoretical received optical power was calculated using fiber attenuation, connector loss, splice loss, splitter loss, and a safety margin, and was subsequently compared with field measurements. The theoretical received power was −17.498 dBm at FAT 1 and −17.509 dBm at FAT 2, while the measured values ranged from −17.19 dBm to −17.66 dBm. The absolute difference between theoretical and measured values ranged from 0.139 to 0.319 dB, with a Mean Absolute Error (MAE) of 0.1905 dB and a Root Mean Square Error (RMSE) of 0.2046 dB. The mean absolute percentage error was 1.09%, while the original percentage comparison between measured and theoretical values ranged from 98.2% to 99.2%. These results indicate close agreement between the theoretical PLB estimates and field measurements for the investigated residential GPON deployment. The findings provide field-based evidence that standardized PLB parameters can reasonably estimate received optical power under the evaluated network configuration, while the limited number of measurement points restricts broader generalization to larger deployments.