A Simple Scheduling Restriction Scheme for Interference Coordinated Networks

Scheduling restriction is attracting much attention in LTE-Advanced as a technique to reduce power consumption and network overhead in interference coordinated heterogeneous networks (HetNets). Such a network with inter-cell interference coordination (ICIC) provides two radio resources with different channel quality statistics. One of the resources is protected (unprotected) from inter-cell interference (hence, called protected (non-protected) resource) and has higher (lower) average channel quality. Without scheduling restriction, the channel quality feedbacks would be doubled to reflect such quality difference of the two resources. We present a simple scheduling restriction scheme that addresses the problem without significant performance degradation. Users with relatively larger (smaller) average channel quality difference between the two resources are scheduled in the protected (non-protected) resource only, and a boundary user, determined by a proportional fair resource allocation (PFRA) under simplified static channels, is scheduled on either of the two resources or both depending on PFRA. Having most users scheduled in only one of the resources, power consumption and network overheads that would otherwise be required for the channel quality feedbacks on the other resource can be avoided. System level simulation of LTE-Advanced downlink shows that the performance degradation due to our scheduling restriction scheme is less than 2%, with the average feedback reduction of 40%.