On the reverse link interference structure for next generation cellular systems

We consider different transmission options for packet data which are classified based on the nature of in-cell interference (ICI) and out-of-cell interference (OCI) power statistics. The categories are: (a) no ICI, averaged OCI; (b) no ICI, bursty OCI; and (c) averaged ICI, averaged OCI. Depending on whether the reverse link transmission is time-multiplexed, one user at a time transmission or simultaneous transmission by multiple users, with or without in-cell orthogonality, the interference structure falls into one of the above three categories. We analyze the throughput performance of the system in each of these cases when incremental redundancy is employed to combat uncertainty in the interference power. We compare the different options, under an in-cell rise-over-thermal (IROT) constraint, and provide some insights for reverse link design for next-generation cellular systems. Our results show that time multiplexed transmissions, despite the bursty OCI power structure, has throughput comparable to an orthogonal multiple user transmission system for small cells.