On Qos performance of different voice codecs over ad hoc networks in underground mines

Ad hoc networks have been paid more attention recently in underground mines. Due to its flexibility and quick deployment, ad hoc networks are widely used in emergency occasions such as mine collapses when communication infrastructure is destroyed. However, underground mines are harsh environment where corrosive water, dust and toxic and explosive gases are commonly present. And the characteristic of confined space in underground mines will lead to diffraction, attenuation, multipath, scattering and fading phenomena that could interfere with radio signals. In this paper, we will focus on studying performance of underground mines´ ad hoc network in a VoIP context by means of simulating VoIP over ad hoc network. We compare the performance of three different codecs, G.711, G.723, and G.729. The results demonstrate that G.723 will obtain highest Mean Opinion Score and is suitable for encoding voice and transmitting through the ad hoc networks.