Delay minimizing user association in cellular networks via hierarchically well-separated trees
- Resource Type
- Conference
- Authors
- Wildman, Jeffrey; Osmanlioglu, Yusuf; Weber, Steven; Shokoufandeh, Ali
- Source
- 2015 IEEE International Conference on Communications (ICC) Communications (ICC), 2015 IEEE International Conference on. :4005-4011 Jun, 2015
- Subject
- Communication, Networking and Broadcast Technologies
Photonics and Electrooptics
Signal Processing and Analysis
Delays
Downlink
Interference
Minimization
Distortion
Optimization
Cellular network
user association
delay minimization
quadratic program
linear approximation
hierarchically well-separated trees
- Language
- ISSN
- 1550-3607
1938-1883
We study downlink delay minimization within the context of cellular user association policies that map mobile users to base stations. We note the delay minimum user association problem fits within a broader class of network utility maximization and can be posed as a non-convex quadratic program. This non-convexity motivates a split quadratic objective function that captures the original problem's inherent tradeoff: association with a station that provides the highest signal-to-interference-plus-noise ratio (SINR) vs. a station that is least congested. We find the split-term formulation is amenable to linearization by embedding the base stations in a hierarchically well-separated tree (HST), which offers a linear approximation with constant distortion. We provide a numerical comparison of several problem formulations and find that with appropriate optimization parameter selection, the quadratic reformulation produces association policies with sum delays that are close to that of the original network utility maximization. We also comment on the more difficult problem when idle base stations (those without associated users) are deactivated.