Coordinated Scheduling for Aircraft In-Cabin LTE Deployment under Practical Constraints

This paper proposes a coordinated multi-point transmission (CoMP) scheduling technique in combination with inter-cell interference coordination (ICIC) techniques, almost blank subframes (ABS) and reduced-power ABS (RP-ABS). It investigates the scheduler performance in the context of an aircraft in- cabin Long Term Evolution (LTE) system deployment. The scheduling problem is solved for an ideal case and a real-world case where LTE system constraints such as common modulation and coding scheme (MCS) assignment per user, channel quality indicator (CQI) reporting and LTE resource allocation (RA) types are considered in the scheduling problem in order to provide a meaningful comparison between real-world and ideal performance. The tradeoff between fairness, which is defined as the lowest variation in user data rates across a large user population, and system throughput is considered as the performance evaluation metric of the system. It is shown that when the LTE constraints are employed, the ideal user data rate and system throughput performance is drastically degraded regardless of the used ICIC technique. In the ideal case, where the LTE constraints are not considered, RP-ABS becomes the optimum tradeoff between fairness and system throughput which achieves a variation of 4.4 Mbps between the lowest and highest user rate, an average user rate of 3 Mbps and an average system throughput of 500 Mbps. However, when the LTE system constraints are taken into account, ABS becomes the optimum technique for the considered onboard system which achieves a variation of 1.7 Mbps, an average user rate of 1.5 Mbps and an average system throughput of 265 Mbps.