## Fairness and Load Balancing in Wireless LANs Using Association Control

Citations: | 85 - 3 self |

### BibTeX

@MISC{Bejerano_fairnessand,

author = {Yigal Bejerano and Seung-Jae Han and Li (Erran) Li},

title = { Fairness and Load Balancing in Wireless LANs Using Association Control},

year = {}

}

### Years of Citing Articles

### OpenURL

### Abstract

Recent studies on operational wireless LANs (WLANs) have shown that the traffic load is often unevenly distributed among the access points (APs). Such load imbalance results in unfair bandwidth allocation among users. We argue that the load imbalance and consequent unfair bandwidth allocation can be greatly alleviated by intelligently associating users to APs, termed association control, rather than having users associate with the APs of strongest signal strength. In this paper, we present an efficient algorithmic solution to determine the user-AP associations for max-min fair bandwidth allocation. We provide a rigorous formulation of the association control problem, considering bandwidth constraints of both the wireless and backhaul links. We show the strong correlation between fairness and load balancing, which enables us to use load balancing techniques for obtaining optimal max-min fair bandwidth allocation. As this problem is NP-hard, we devise algorithms that achieve constant-factor approximation. In particular, we present a 2-approximation algorithm for unweighted users and a 3-approximation algorithm for weighted users. In our algorithms, we first compute a fractional association solution, in which users can be associated with multiple APs simultaneously. This solution guarantees the fairest bandwidth allocation in terms of max-min fairness. Then, by utilizing a rounding method, we obtain the integral solution from the fractional solution. We also consider time fairness and present a polynomialtime algorithm for optimal integral solution. We further extend our schemes for the on-line case where users may join and leave dynamically. Our simulations demonstrate that the proposed algorithms achieve close to optimal load balancing (i.e., maxmin fairness) and they outperform commonly-used heuristic approaches.

### Citations

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Citation Context ... allocation is max-min fair. Theorem 1: The problem of finding a max-min fair integral association is NP-hard. Proof: This Theorem can be proved by using a simple reduction from the partition problem =-=[29]-=- to the max-min fair integral association problem. Due to space limitation details of the proof have been omitted. Example 3: Consider a wireless system with 3 APs, , and 5 users, , as depicted in 3 T... |

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Citation Context ...ng (i.e., max-min fairness) and they outperform commonly used heuristics. Index Terms—Approximation algorithms, IEEE 802.11 WLANs, load balancing, max-min fairness. I. INTRODUCTION RECENT studies [2]–=-=[4]-=- on operational Wireless LANS (WLANs) have shown that the traffic load is often distributed unevenly among the access points (APs). In WLANs, by default, each user scans all available channels to dete... |

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Citation Context ...e adjacent APs may carry only light load or be idle. Such load imbalance among APs is undesirable as it hampers the network from providing fair services to its users. As suggested in existing studies =-=[5]-=-–[7] the load imbalance problem can be alleviated by balancing the load among the APs via intelligently selecting the user-AP association, termed association control. Association control can be used t... |

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Citation Context ...jacent APs may carry only light load or be idle. Such load imbalance among APs is undesirable as it hampers the network from providing fair services to its users. As suggested in existing studies [5]–=-=[7]-=- the load imbalance problem can be alleviated by balancing the load among the APs via intelligently selecting the user-AP association, termed association control. Association control can be used to ac... |

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Citation Context ...ciation accordingly. In this paper, we do not address the issue of providing fair service within each AP. We assume that such a feature is available, for instance, by using the IEEE 802.11e extension =-=[24]-=- or some fair scheduling mechanism, such as [25]–[27]. C. Periodic Offline Optimization We motivate the need for optimization by showing the weakness of the existing heuristic load balancing mechanism... |

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Citation Context ...reatest number of available channels. In [14], the fairness issue is addressed by restricting the number of available channels for new calls that are made in overlapping areas. Tinnirello and Bianchi =-=[15]-=- take into account the channel conditions of the users. Recently, load balancing integrated with coordinated scheduling technique has been studied in [11] for CDMA networks. However, these techniques ... |

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