  Satellite-based quantum communications including quantum key distribution
(QKD) represent one of the most promising approaches toward global-scale
quantum communications. To determine the viability of transmitting quantum
signals through the atmosphere, it is essential to conduct atmospheric
simulations for both uplink and downlink quantum communications. In the case of
the uplink scenario, the initial phase of the beam's propagation involves
interaction with the atmosphere, making simulation particularly critical. To
analyze the atmosphere over the Indian subcontinent, we begin by validating our
approach by utilizing atmospheric data obtained from the experiments carried
out in the Canary Islands within the framework of Quantum Communication (QC).
We also verify our simulation methodology by reproducing simulation outcomes
from diverse Canadian locations, taking into account both uplink and downlink
scenarios in Low Earth Orbit (LEO). In this manuscript, we explore the
practicality of utilizing three different ground station locations in India for
uplink-based QC, while also considering beacon signals for both uplink and
downlink scenarios. The atmospheric conditions of various geographical regions
in India are simulated, and a dedicated link budget analysis is performed for
each location, specifically focusing on three renowned observatories: IAO
Hanle, Aries Nainital, and Mount Abu. The analysis involves computing the
overall losses of the signal and beacon beams. The findings indicate that the
IAO Hanle site is a more suitable choice for uplink-based QC when compared to
the other two sites.
