A Frame Structure with Precoding for Bidirectional Low Latency Applications

Abstract

The advent of 5G will introduce new classes of services which demand different requirements compared to traditional radio systems. Of particular interest is the Ultra-Reliable Low Latency Communication (URLLC), which restricts the PHY layer to short deadlines for delivering the radio message. For OFDM based systems, the radio frame structure should be able to support large variations in data rates of any two given communicating nodes. Legacy radio frame structures did not take such restrictions into account. In this paper, we present a flexible radio frame structure where, under low latency constraints, large variations in the bi-directional data rates can be easily supported using time and frequency duplexing. As such, a fair subdivision of the radio resources which fit into the exact requested data rates becomes possible. To maintain high spectral efficiency, the bi-directional traffics are packed close to each other in frequency domain, which leads to considerable amount of cross talk. To suppress this interference, we introduce a novel precoder which mitigates the cross talk interference in baseband.