  Recognizing the growing significance of contamination from weak gravitational
lensing B-modes induced by Large Scale Structure, we investigate a thorough
examination of delensing methods aiming at enhancing the sensitivity of r in
primordial B-mode detection experiments. In this study, we focus on two
specific delensing approaches. One approach involves computing the
gradient-order lensing B-mode template by cross-correlating the E-mode with the
lensing potential, and subsequently subtracting it from the observed B-mode
signal. Another method entails remapping the observations using the estimated
deflection angle. Then demonstrate the delensing efficiency using the simulated
maps from future CMB polarization experiments, including two ground-based
observations: sub-1 m small aperture telescope and 6 m large aperture
telescope, and one future space mission with medium aperture telescope. The
results reveal that delensing efficiency will be 40% with ground-based
small-aperture only, and increases to 65% when combined with a large-aperture
telescope. Furthermore, the future satellite experiment achieves an impressive
delensing efficiency of approximately 80%.
