Equivalent Capacity-Based Joint Multilevel Coding and Space–Time Transmit Diversity Design

A novel space-time block-coding-assisted and sphere-packed multilevel-coded (STBC-SP-MLC) modulation arrangement is proposed, which combines an MLC-based scheme with a twin-antenna-aided STBC for the sake of providing a transmit diversity gain. The SP modulation invokes a 4D D ₄ constellation space. A new bit-to-SP symbol mapper is designed for the sake of improving the system´s performance. This involves mapping the MLC bits to the SP symbols of Layer-1 and Layer-2 in D ₄ space. The binary switching algorithm is used to determine the optimum cost function used for designing different mapping strategies. The so-called equivalent capacity-based design invoking the 4-D signal space is used to determine the optimum coding rate of the STBC-SP-MLC scheme´s component codes. Finally, we investigate a hybrid bit-to-SP symbol-mapping strategy for the STBC-SP-MLC scheme, which is capable of providing unequal error protection.