Diversity and Subcarrier Index Modulation Based Multiple Access for the Tactile Internet

We consider multiple access of users with different Quality of Service (QoS) requirements. One user transmits high-priority (low-latency and high-reliability) but sporadic traffic, such as some types of Tactile Internet traffic. The other user transmits low-priority traffic with less stringent requirements on latency and reliability and the traffic arrival process is not sporadic. To meet the QoS requirements of the high-priority traffic while being efficient in utilizing resources, we use subcarrier index modulation (SIM) for the low-priority traffic and diversity for the high-priority traffic. To reduce the complexity, such multiple access is applied within small groups of resources separately. We develop low-complexity maximum likelihood detection algorithms. Analysis and simulation results show that the performance of the low-priority traffic is almost not affected by the presence of high-priority traffic while the desired performance of the latter is achieved.