A Flexible Frame Structure for 5G Wide Area

In this paper we present a 5G frame structure designed for efficient support of users with highly diverse service requirements, including mobile broadband (MBB) data, mission critical communication (MCC), and massive machine communication (MMC). The proposed solution encompasses flexible multiplexing of users on a shared channel with dynamic adjustment of the transmission time interval (TTI) in coherence with the service requirements per link. This allows optimization of the fundamental trade-offs between spectral efficiency, latency, and reliability for each link. The frame structure is based on in-resource physical layer control signaling that follows the corresponding data transmission for each individual user. The principle of in-resource control signaling has numerous advantages; it presents a highly flexible and scalable solution, it allows joint beamforming for control and data transmission, as well as efficient time-frequency inter-cell interference coordination. Numerical results are presented, including simple comparison against LTE.