Power Prediction prior to Scheduling Combined with Equal Power Allocation for the OFDMA UL

Inhalt:
The orthogonal assignment of radio resources in Orthogonal Frequency Division Multiple Access (OFDMA) systems allows to exploit multiuser diversity in frequency and time domains. The instantaneous data rate estimated on each resource for each User Equipment (UE) by the scheduling policy needs to reflect accurately the data rate effectively achieved after power allocation. However, when the total amount of resources are allocated opportunistically by the scheduling policy without any constraint with respect to the number of frequency resources assigned to each UE, the transmit power on each resource may be unknown to the scheduling policy. Indeed, scheduling and power allocation are coupled by the transmit power. In this paper, a realistic prediction of the average transmit power for the frequency resources of each UE is obtained prior to Proportional Fair (PF) scheduling and is computed based on an exponential moving average in the Uplink (UL) assuming Equal Power Allocation (EPA) among frequency resources. Simulation results have shown that the proposed method is able to efficiently estimate the instantaneous data rate even in a challenging scenario with high co-channel interference such as when Device-to-Device (D2D) communications underlay the cellular network.