UC Irvine

We introduce the concept of space-time supermodulation according to which additional low-rate and highly reliable information can be transmitted on top of traditionally modulated and space-time encoded information, without increasing the transmitted block length or degrading their errorrate 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 supermodulation can be efficiently used in the context of machinetype 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.