  We present GMRT observations of the Galactic microquasar GRS 1915+105 at 1.28
GHz for 8 days from 2001 June 18 to July 1. We have seen several isolated radio
flares of varying magnitudes (20 - 50 mJy) and durations (6 - 35 min) and we
model them as due to adiabatically expanding synchrotron emitting clouds
(synchrotron bubbles) ejected from the accretion disk. By applying this model,
we provide a new method to estimate the electron power-law index p, hence the
spectral index, from single frequency radio observations. This method does not
require correction for the optical depth time delay effects which may be
important in the case of optically thick radio emission. Using our estimated
value of p and simultaneous multiwavelength data from literature, we have
calculated the time of ejection of the synchrotron plasma and the time delays
at different observed frequencies. Our estimates are in good agreement with the
observed time delays.
