Uplink control channel design for 5G ultra-low latency communication

The fifth generation mobile communication system (5G) under development currently is envisioned to support ultra-low latency traffic, which requires an air interface latency of 1ms or less. In this paper, we focus on shortened Physical Uplink Control Channel (sPUCCH) design based on Transmission Time Interval (TTI) shortening. To fulfill the strict latency requirement, sequence-based sPUCCH (SS-PUCCH) containing only 2 Single Carrier-Frequency Division Multiple Access (SC-FDMA) symbols is proposed. Symbol-level frequency hopping is utilized to harness frequency diversity gain and improve reliability. Moreover, the theoretical performance of the proposed SS-PUCCH design is deduced. Extensive simulation is also conducted to explore the influence of short TTI and evaluate the performance of different sPUCCH designs. It is found that our proposed SS-PUCCH design outperforms DMRS based sPUCCH (DS-PUCCH) by approximately 3dB for 1 bit ACK/NACK transmission and 4.5dB for 2 bits ACK/NACK transmission.