Dynamic Resource Allocation for Time-varying Channels in Next Generation Cellular Networks Part I: A Mathematical Framework

Next generation cellular networks will present challenging interference scenarios due to the difficulty of centralized planning and continued support of mobility. In this context, modeling and analytical study is still required for time-varying inter-cell interference and imperfect resolution of the channel state at the transmission end. In this paper, we first present a mathematical framework using information-theoretic quantities that can be applied to the analysis of heterogeneous networks and provide insight into the design of resource scheduling policies. Specifically, we consider the problem of variable resource allocation for IR-HARQ schemes across time-varying channels, arising from either fading with unknown or partial channel state information, time-varying interference, or a combination of both. With our framework, we avoid the need for extensive simulations and can flexibly address the development of resource allocation policies with and without constraints on the outage probability, which to a first degree represents the latency of the protocol. The policies are distributed, applicable for uplink and downlink, and based on the dynamic adaptation of the physical dimensions across HARQ rounds. Our results show a significant gain from adapting the resources across rounds, and we identify specific cases where it provides the highest gain when compared to fixed-allocation schemes. Index Terms Heterogeneous networks, resource allocation, rate adaptation, LTE, HARQ, incremental redundancy