Link Estimation of Different Indian Cities Under Fog Weather Conditions

Abstract

The high data rate, unlicensed spectrum, and secure communication make FSO system attractive to be used in next-generation wireless networks. However, the atmospheric effects like rain, snow, haze and fog severely degrade the Free Space Optics (FSO) system performance. Out of all weather condition fog heavily attenuates the optical signal. Therefore, before establishing FSO link a complete metrological survey of the area should be done. In this paper, we present a link availability analysis of two Indian cities namely Amritsar and New Delhi under fog weather condition. In literature, various techniques are mentioned that are used to enhance the reliability of FSO system under harsh weather conditions. Orthogonal Frequency Division Multiplexing is widely used in FSO. To achieve high data rate and high link availability under fog, we have designed a coherent detection Orthogonal Frequency Division Multiplexing with spatial diversity FSO system and calculate the link availability for two Indian cities. In literature, only theoretical estimation of link availability is given but in this research, a practical estimation of link availability is presented. At first, the theoretical estimation of link availability is presented on the basis of visibility data. The visibility data is simulated by OPTISYSTEM software and link performance is calculated on the basis of Bit Error Rate and Signal to Noise Ratio. The practical estimation of link availability is calculated and it is concluded that link availability of Amritsar is higher than that of New Delhi. The designed system significantly improves the link availability even under harsh weather conditions like fog.