Abstract
We introduce the concept of Space-Time Super-Modulation according to which additional lowrate and highly reliable information can be transmitted on top of traditionally modulated and spacetime encoded information, without increasing the transmitted block length or degrading their error-rate performance. This is achieved by exploiting the temporal redundancy introduced by the space-time block codes and, specifically, by efficiently mapping transmission patterns to specific information content. We show that Space-Time Super-Modulation can be efficiently used in the context of machine-type communications to enable “one-shot”, “grant-free" joint medium access and rateless data transmission while reducing or even eliminating the need for transmitting preamble sequences. As a result, compared with traditional approaches that use correlatable preamble sequences or encoded preambles to transmit the signature information of transmitted packets, Space-Time Super-Modulation can achieve significant throughput gains. For example, we show up to 35% throughput gains from the second best examined preamble-based scheme when transmitting blocks of 200 bits.