Optimal Collaborative Access Point Association

In Wireless NetworksOuldooz Baghban

KarimiSchool of Computing ScienceSimon Fraser University

Jiangchuan LiuSchool of Computing ScienceSimon Fraser University

Jennifer RexfordDepartment of Computer Science

Princeton University

INFOCOM 2014

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Increase in Mobile Data Usage

Not Enough Wireless Resources

Increase in Mobile Traffic 52% Increase over a period of a year

More offloading from cellular

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INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Popularity of Wireless Local Area Networks

Dense availability of WiFi resources Data collected in Greater Vancouver urban residential area High availability of resources Low availability of owned resources

Wasting excess/unused resources

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INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

WiFi Popularity: Real-World Example

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Insights on Collected Data

Number of access points Co-channel access points Ineffective association based on highest

signal quality Interference and collision

Same Upstream Internet Service Provider Collaboration: sharing excess WiFi Capacity

Private Access Point + Hot Spot Optimal collaborative access point association

Centralized

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Centralized Access Optimization

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INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Association Problem

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System Components Users

Access Points Local access point

Provides access to its registered devices

Host access point Provides access to external nodes Services quality for local users

Shared upstream provider Opportunity

Centralized access optimization Clustering Reduced billing complexity

Limitations No central control over

Deployment Sharing limits

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Example

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(a) Link Capacities (b) Non-collaborative

(c) Optimal Collaborative Association (d) Optimal Collaborative with Concurrent Associations

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Proportional Fair Access Point Association

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Network Utility Maximization (NUM) Framework Proportional Fairness [Li et al., 2008]

Maximize throughput: Proportional fair Subject to

Time/medium sharing among co-channel access points Time/medium sharing among users on the same access point Limit for external users

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

PF with Sharing Results

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Placement of access points based on measurement data

Increased Overall throughput

Dropped rate experienced only at a few high-rate users

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

PF with Sharing Results

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Increased throughput with increase in the number of access points Maintain collision Concurrent connections

Maintain throughput with increased users per access point Unused extra access points

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

PF with Sharing Results

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Define cost of association

Higher external cost of association solves the dropped rate problem

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Conclusion

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Higher mobile data usage requires higher wireless resources

Dense, accessible, and inexpensive WLAN resources Measurements to confirm

Offload from cellular networks to dense WLAN networks

Challenges & Solutions in WLANS Collaborative access Centralized association optimization in upstream provider Used measurements for simulations Up to 140% throughput increase

INFOCOM 2014 Optimal Collaborative Access Point Association in Wireless Networks

Thank you!

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