To layer or not to layer: Balancing transport and physical layers in wireless multihop networks

Mung Chiang

Research output: Contribution to journalConference articlepeer-review

131 Scopus citations


In a wireless ad hoc network with multihop transmissions and interference-limited link rates, can we balance power control in the physical layer and congestion control in the transport layer to enhance the overall network performance, while maintaining the stability, robustness, and architectural modularity of the network? We present a distributive power control algorithm that couples with the original TCP protocols to increase the end-to-end throughput and energy efficiency of the network. Under the rigorous framework of nonlinearly constrained optimization, we prove the convergence of this coupled system to the global optimum of joint power control and congestion control, for both synchronized and asynchronous implementations. The rate of convergence is geometric and a desirable modularity between the transport and physical layers is maintained. In particular, when the congestion control mechanism is TCP Vegas, that a simple utilization in the physical layer of the router buffer occupancy information suffices to achieve the joint optimum of this cross layer design. Both analytic results and simulations illustrate other desirable properties of the proposed algorithm, including robustness to channel outage and to path loss estimation errors, and flexibility in trading-off performance optimality for implementation simplicity.

Original languageEnglish (US)
Pages (from-to)2525-2536
Number of pages12
JournalProceedings - IEEE INFOCOM
StatePublished - 2004
EventIEEE INFOCOM 2004 - Conference on Computer Communications - Twenty-Third Annual Joint Conference of the IEEE Computer and Communications Societies - Hongkong, China
Duration: Mar 7 2004Mar 11 2004

All Science Journal Classification (ASJC) codes

  • General Computer Science
  • Electrical and Electronic Engineering


  • Congestion control
  • Convex optimization
  • Cross-layer design
  • Energy-aware protocols
  • Lagrange duality
  • Network utility
  • Power control
  • Transport Control Protocol
  • Wireless ad hoc networks


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