MPR-aware scheduler for carrier aggregation transmissions in LTE uplink

Abstract

Unlike previous Long Term Evolution (LTE) releases, LTE - Advanced (LTE-A) allows the use of non-contiguous resource allocation in the uplink (UL). This feature leads to increase the spectral efficiency thanks to link performance gains obtained from frequency diversity. At the same time, non-contiguous allocations bring higher peak to average power ratio (PAPR) and so potentially higher intermodulation distortion and adjacent channel leakage-power ratio (ACLR). Power derating has been proposed as a means to avoid this problem and thus user equipments (UEs) must reduce their maximum transmitted power. However, the additional link loss on power limited UEs partially counteracts the gain brought by multi-cluster allocation. In this sense, this paper proposes to include Maximum Power Reduction (MPR) information in opportunistic scheduling decisions. The new scheduling proposal is able to determine whether multi-clustering leads to a net gain in instantaneous throughput or if localized allocation is preferred. The proposed method is compared to other scheduling techniques and it is also analyzed in different inter-site distance scenarios. Results show that considering MPR in opportunistic decisions can lead to overall cell performance improvements.