  A bounce universe model with a scale-invariant and stable spectrum of
primordial density perturbations was constructed using a consistent truncation
of the D-brane dynamics from Type IIB string theory. A coupling was introduced
between the tachyon field and the adjoint Higgs field on the D3-branes to lock
the tachyon at the top of its potential hill and to model the bounce process,
which is known as the Coupled Scalar and Tachyon Bounce (CSTB) Universe. The
CSTB model has been shown to be ghost free, and it fulfils the null energy
condition; in addition, it can also solve the Big Bang cosmic singularity
problem. In this paper we conduct an extensive follow-up study of the parameter
space of the CSTB model. In particular we are interested in the parameter
values that can produce a single bounce to arrive at a radiation-dominated
universe. We further establish that the CSTB universe is a viable alternative
to inflation, as it can naturally produce a sufficient number of e-foldings in
the locked inflation epoch and in the post-bounce expansion to overcome the
four fundamental limitations of the Big Bang cosmology, which are flatness,
horizon, homogeneity and singularity, resulting in a universe of the current
size.
