Interference-aware Proportional Fairness for Multi-rate Wireless Networks

In this paper, we consider how proportional fairness in wireless networks is impacted by spatial reuse and the interference it produces. We observe that, in scenarios where spatial reuse is possible (e.g., in high-density WLAN environments), the classic notion of time-based proportional fairness can be severely impacted: some users might experience very large interference penalties while other users might get larger bandwidth proportions than what they would have received with time-based proportional fairness and no spatial reuse. To account for this, we introduce the concept of inter\-ference-aware STDMA time-based proportional fairness ($i$-STPF), and compare it to ordinary STDMA time-based proportional fairness (STPF). We present the $\epsilon i$-STPF scheduling algorithm, and prove that it approximates the time-based fair bandwidth allocation (up to a small positive constant $\epsilon$), while providing an aggregate throughput that is within a constant factor from optimal. We also present a heuristic $i$-STPF scheduling algorithm and compare it through simulation to a similar heuristic STPF scheduler, and to an interference-aware, rate-based scheduler. The results show that the i-STPF scheduler achieves excellent aggregate throughput while maintaining a close approximation to time-based fairness without interference.