From this study, it has been found that
although there is packet loss rates in the
network up to 20%, the user perception of
G.711 and G.729 are not significantly
different. This is consistent with the previous
works based on Thai users [11, 18] and this
evidence confirms that G.729 can be used
instead of G.711 without significant
difference of voice quality perception,
whereas, G.729 only requires about one third
of the bandwidth used by G.711, including
the packet header.
However, packet loss rates are more
than 20% (e.g. 30%-40%). This will be the
focus of future work.