1st Annual Conference on Broadband Networks

Research Article

A scheduling framework for UWB & cellular networks

  • @INPROCEEDINGS{10.1109/BROADNETS.2004.12,
        author={Arjunan Rajeswaran and Gyouhwan Kim and Rohit Negi},
        title={A scheduling framework for UWB \& cellular networks},
        proceedings={1st Annual Conference on Broadband Networks},
        keywords={MAC  Ultra Wide Band  Wireless communications  ad-hoc network  cross layer design  scheduling},
  • Arjunan Rajeswaran
    Gyouhwan Kim
    Rohit Negi
    Year: 2004
    A scheduling framework for UWB & cellular networks
    DOI: 10.1109/BROADNETS.2004.12
Arjunan Rajeswaran1,*, Gyouhwan Kim1,*, Rohit Negi1,*
  • 1: Department of Electrical and Computer Engineering, Carnegie Mellon University
*Contact email: arjunan@cmu.edu, gyouhwak@ece.cmu.edu, negi@ece.cmu.edu


The max-min fair scheduling problem in wireless ad-hoc networks is a non-convex optimization problem. A general framework is presented for this optimization problem and analyzed to obtain a dual problem, which involves solving a series of optimization sub-problems. In the limit of infinite bandwidth (W → ∞), the scheduling solution reduces to simultaneous transmission (spread spectrum) on all links (R. Negi and A. Rajeswaran, March 2004). This motivates the analysis of the scheduling problem in the ultra wide band (UWB) regime (W ≫ 1, but finite), a model for certain practical radios. A quadratic (in 1/W) lower bound to the single link capacity function is developed, which simplifies the dual sub-problem to a quadratic optimization (R. Negi and A. Rajeswaran, December 2004). The solution to this sub-problem is then obtained under both total power and power spectral density constraints. This solution is utilized to iteratively construct the schedule (subband sizes) and power allocation, thus optimally solving the UWB max-min fair scheduling problem, to within any desired precision. Simulations on medium sized networks demonstrate the excellent performance of this scheme. A cellular architecture (not necessarily UWB) may also be considered in this framework. It is proved that frequency division multiple access is the optimal scheduling for a multi-band cellular architecture.