Two-Dimensional Resource Pattern Optimization for Interference Avoidance in Heterogeneous Networks

Interference management for heterogeneous networks (HetNets) has been a research highlight in recent years; one effective method is interference avoidance by resource allocation. Typical resource-allocation methods are arranging orthogonal resources between a macrocell and femtocells, such as in the frequency domain in intercell interference coordination (ICIC) or in the time domain in enhanced ICIC (eICIC). However, wireless channels experience time–frequency fading appealing for a 2-D resource-allocation scheme. By optimizing the resource pattern based on variable channel conditions and by introducing a group lasso term, our scheme exploits channel variations in both the time and frequency domains and, in addition, avoids the interference. By grouping the resources in our optimization model, our scheme is flexible and robust against heavy bursty traffic. It is also lightweight in terms of coordination overhead and is completely distributed, making it suitable for a standard Long-Term Evolution (LTE) procedure. Extensive simulations investigate the effect of the coordination period and the group number on different performance metrics and the effectiveness of our proposed method compared with sole frequency-domain and time-domain resource-allocation approaches.