Multiple Access Interference Suppression for TWSTFT Applications

Multiple access interference (MAI) is one of the unstable sources of the two-way satellite time and frequency transfer (TWSTFT), and causes an estimation error of the signal arrival time. To suppress MAI, the successive interference cancellation (SIC) procedure is implemented on the software-defined receiver. It generates MAIs and subtracts them from the received signal to become an interference-free signal. By performing TWSTFT with SIC, the short-term stability of the UTC(TL)- UTC(KRIS) was improved so that the time deviations were reduced from 0.67 τ
^-1/2
to 0.48 τ
^-1/2
ns, and the long-term measurement results were consistent with those obtained by the conventional receiver.