Unequal error protection for layered source coding using MIMO technology

The use of multiple-input, multiple-output (MIMO) technology is proposed to provide unequal error protection (UEP) for layered source coding. Two priority layers are considered: a base (high priority (HP)) layer and an enhancement (low priority (LP)) layer. The MIMO is composed of two transmit antennas and two receive antennas. The HP bit stream is modulated by using four quadrature amplitude modulation (4-QAM) and the LP bit stream is modulated by using 16-QAM. The HP and the LP symbols are then coded by using a spatial-time block coding and multiplexed before transmission. The performance of the proposed system is compared with an equal error protection (EEP) system of 64-QAM and two transmit and two receive antennas. The EEP system uses spatial diversity in its MIMO to improve the decision reliability at the receiver. Both systems provide a similar capacity. The simulation results show a considerable improvement in performance for the UEP system over the EEP one.