Achievable Net-Rates in Multi-User OFDMA with Partial CSI and Finite Channel Coherence

This paper derives an analytical framework to evaluate achievable rates in a multi-user OFDMA system. Opportunistic schedulers and OFDMA allow for exploiting multi-user diversity using a flexible and simplified resource assignment. However, the granularity of resource assignments determines the gains in spectral efficiency and requires to consider signaling overhead and finite channel coherence. Additionally to the signaling and pilot overhead, practical systems suffer from partial CSI, i.e., neither scheduler nor receiver have exact knowledge of the channel state. This paper investigates the trade-off between achievable net- rates and channel characteristics as well as system parameterization. An analytical framework for the expected net-rates in a multi-user system with partial CSI at scheduler and receiver is derived.