| PhD Seminar

Name of the Speaker: Mr. Advait Sai Narayan (EE19D403)
Guide: Prof. Devendra Jalihal
Venue: ESB-244 (Seminar Hall)
Online meeting link: https://meet.google.com/prv-xsbn-cwm
Date/Time: 21st November 2023 (Tuesday), 2:00 PM
Title: Blind Estimation of PCMA signal parameters using the '2pth' order cyclic moment.


Paired Carrier Multiple Access (PCMA) has been introduced as a satellite communication technology that allocates two radio-frequency (RF) signals the same frequency band, achieving higher bandwidth efficiency. PCMA employs a cooperative full duplex scheme. Two ground stations communicate with each other using the same carrier frequency via a satellite transponder. The transponder then relays the superposed signal back to the two ground stations.The ground stations then estimate their contribution in the received signal and subtract it out to get the desired signal. The focus of the present work is on the blind estimation of the signal parameters of the two constituent signals, such as frequency offset, timing offset, phase offset and relative power difference. Existing methods available in literature use the signal's 'pth' order cyclic moment to perform the estimation. Here, 'p' denotes the modulation order of the signal (ex., p=4 for QPSK, p=8 for 8PSK). However, it has been observed that it becomes increasingly difficult to estimate the weaker signal's transmission parameters with increase in power difference between the signals. The strength of the features used to estimate the signal parameters decreases exponentially for the weaker signal with increase in power difference, making the estimation process difficult.

We present a new approach to the problem of estimating the signal parameters that involves using the '2pth' order cyclic moment of the signal. We demonstrate its working even in cases when the power difference between the signals is large. A mathematical basis is provided to show its working. A comparison is done to show the working of the proposed method in cases when the other method fails.