PeerCast: Improving link layer multicast through cooperative relaying

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


Wireless multicast applications, such as MobiTV, web telecast, and multimedia classrooms, are gaining rapid popularity. The broadcast nature of the wireless channel is amenable to such multicasts because a single packet transmission can be received by all clients. Unfortunately, the rate of this transmission is bottlenecked by data rate of the weakest client, degrading system performance. Attempts to increase the data rate results in lower reliability and higher unfairness. This paper presents PeerCast, a wireless multicast protocol that engages clients in cooperative relaying. The main idea is simple. Instead of multicasting at the bottleneck rate, the access point transmits at a high rate and suitably chooses a few stronger clients to relay the packet to the weaker ones. Multiple transmissions of the same packet, each at higher rate, can achieve better throughput than one transmission at the low, bottleneck rate. We propose a new simultaneous reply-back scheme for clients and detect the power level to estimate the AP's transmission strategy. PeerCast translates these ideas into a functional system using off-the-shelf hardware. Performance evaluation on a 9 node testbed demonstrates consistent throughput and reliability improvements over 802.11. Simulations in QualNet indicate similar trends in large-scale networks.

Original languageEnglish (US)
Title of host publication2011 Proceedings IEEE INFOCOM
Number of pages9
StatePublished - 2011
Externally publishedYes
EventIEEE INFOCOM 2011 - Shanghai, China
Duration: Apr 10 2011Apr 15 2011

Publication series

NameProceedings - IEEE INFOCOM
ISSN (Print)0743-166X



ASJC Scopus subject areas

  • General Computer Science
  • Electrical and Electronic Engineering


Dive into the research topics of 'PeerCast: Improving link layer multicast through cooperative relaying'. Together they form a unique fingerprint.

Cite this