Towards energy efficient VoIP over wireless LANs

ABSTRACT

Wireless LAN (WLAN) radios conserve energy by staying in sleep mode. With real-time applications like VoIP, it is not clear how much energy can be saved by this approach since packets delayed above a threshold are lost. In this work we propose the GreenCall algorithm to derive sleep/wakeup schedules for the WLAN radio to save energy during VoIP calls. The schedules provided by GreenCall consider the energy versus loss-rate tradeoff to ensure application quality is preserved. We implement GreenCall on commodity hardware and study its performance and point out possible limitations. We further extensively evaluate the effect of diverse network paths and different application parameters on possible energy savings through trace-based simulations. We show that, in spite of the interactive, real-time nature of voice, a significant amount of energy can be conserved through GreenCall.

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INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.1 Network Architecture and Design

General Terms:
Algorithms, Measurement, Performance

Keywords:
VoIP, energy efficiency, wireless LANs