| PhD Seminar

Name of the Speaker: Mr. Ramasamy PL (EE15D204)
Guide: Prof. Sankaran Aniruddhan
Online meeting link: https://meet.google.com/nkv-bgoc-jpz
Date/Time: 10th June 2024 (Monday), 7:30 PM
Title: Analysis and Design of RF Canceller for Self-Interference Cancellation (SIC) in Full-duplex Radios.

Abstract :

In-band full-duplex (IBFD) is a wireless communication scheme where data transmission and reception occur simultaneously over the same frequency. One of the main challenges in implementing IBFD is dealing with the Self-Interference (SI) caused by the powerful transmit signal onto the receive signal.

In this talk, we will provide a detailed theoretical analysis of phase-based RF cancellation. We will discuss the lower bound on the residual signal after multi-stage cancellation and derive the upper bound on the self-interference cancellation (SIC) across an RF channel, considering factors such as group delay and amplitude imbalance between the cancelling signals. Our model demonstrates improved accuracy of SIC compared to existing literature and highlights the enhanced convergence time of the canceller loop compared to the classical multi-tap RF canceller.

In the second part of the talk, we will introduce the concept of a “Spectral shaper” circuit that mimics the SI signal and significantly improves the SIC. We will describe the RF front-end architecture of the proposed canceller and its implementation on a two-layer PCB at 2.45 GHz using COTS components. The performance of the canceller was analyzed under various practical conditions, and the results will be discussed. The proto-model of the canceller was able to suppress a +27 dBm transmit signal by 70.8 dB over a 20 MHz channel exclusively in the RF domain. Towards the end, we will discuss the over-the-air (OTA) measurements conducted using the proposed RF transceiver and conclude the talk by drawing a direct comparison with the state-of-the-art.