Channel Impulse Response Measurement for Characterizing The Ionosphere
Communication Channel Over Java Island Indonesia
Abstract
For designing a digital High Frequency (HF) radio communication system
in the skywave propagation mode, Delay spread and Doppler spread are the
fundamental parameters of ionosphere channel characteristics that need
to be known. Although the International Telecommunication Union (ITU)
already provides general classification values for three different
regions and conditions as a recommendation, the empirical Delay spread
and Doppler spread values are still needed for an optimum design. As the
role of HF communication in Indonesia is still important and its
development technology is continued, the empirical data of ionosphere
channel characteristics are also needed. However, the comprehensive
empirical data of ionosphere channel characteristics over Indonesia is
difficult to find. In this research, we developed an Ionosphere Channel
Impulse Response (CIR) measurement system based on Software Defined
Radio (SDR) with purpose to obtain the empirical values of Delay spread
and Doppler spread. The measurement system is placed in Java Island
Indonesia, which is in the Low latitude - Equatorial Ionosphere Anomaly
(EIA) region. The specification of the system was determined based on
the increased values of ITU parameters for low-latitude regions in order
to be able to capture the possibility of higher values. The early
measurement result shows slightly different values from ITU
recommendation which is probably due to the EIA regions effect. This
system is ready to collect further data to characterize the ionospheric
communication channel comprehensively and investigate the space weather
impact on HF communication systems.