A case for WiFi relay: Improving VoIP quality for WiFi users

Amit Mondal*, Cheng Huang, Jin Li, Manish Jain, Aleksandar Kuzmanovic

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations


Voice over Internet (VoIP) has been experiencing enormous growth in recent years. While posed to replace traditional PSTN for both enterprise and residential customers, VoIP has yet to achieve the same level of quality and reliability as PSTN. One key challenge is that a growing segment of customers is increasingly relying on WiFi connections. VoIP over WiFi (VoWiFi) experiences significant degradation in quality because of packet losses, mostly due to WiFi's low capacity, varying signal strength, interference, etc. To understand this problem, we have developed and deployed a comprehensive measurement platform in a global enterprise network. From large-scale real-world traces, we quantitatively analyze the impact of WiFi connections and study measures to mitigate such impact. Our results confirm that WiFi connections incur significantly more packet losses than wirelines, but these losses can be effectively concealed by sending each packet up to five times (heavy replication). Due to WiFi's inherent overhead, heavy replication only marginally increases WiFi airtime. To avoid the overhead on wirelines, we further propose a relay-based solution, where heavy replication only occurs between endpoints and nearby relays, and is removed before packets are transmitted on inter-branch long haul links or the public Internet. The solution has been implemented and deployed in the global enterprise network, and measurement results confirm that it can indeed greatly improve the performance of VoIP for WiFi users. In particular, it reduces the percentage of poor calls from 35% to 10%; and increases the percentage of acceptable ones from 45% to 70%.

Original languageEnglish (US)
Title of host publication2010 IEEE International Conference on Communications, ICC 2010
StatePublished - 2010
Event2010 IEEE International Conference on Communications, ICC 2010 - Cape Town, South Africa
Duration: May 23 2010May 27 2010

Publication series

NameIEEE International Conference on Communications
ISSN (Print)0536-1486


Other2010 IEEE International Conference on Communications, ICC 2010
Country/TerritorySouth Africa
CityCape Town

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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