Modem based on sphere packing techniques in high-dimensional Euclidian sub-space for efficient data over voice communication through mobile voice channels

The increased penetration of cellular networks has made voice channels widely available ubiquitously. On the other hand, mobile voice channels possess properties that make them an ideal choice for high priority, low-rate real-time communications. Mobile voice channel with the mentioned properties, could be utilised in emergency applications in vehicular communications area such as the standardised emergency call system planned to be launched in 2015. This study aims to investigate the challenges of data transmission through these channels and proposes an efficient data transfer structure. To this end, a proper statistical model for the channel distortion is proposed and an optimum detector is derived considering the proposed channel model. Optimum symbols are also designed according to the derived rule and analytical bounds on error probability are obtained for the orthogonal signaling and sphere packing techniques. Moreover, analytical evaluation is performed and appropriate simulation results are presented. Finally, it is observed that the proposed structure based on the sphere packing technique achieves superior performance compared with prior works in this field. Although the ideas offered in this study are utilised to cope with voice channel non-idealities, the steps taken in this study could also be applied to channels with similar conditions.