A two-phase loss differentiation algorithm for improving TFRC performance in IEEE 802.11 WLANs

Sangheon Pack, Xuemin Shen, Jon W. Mark, Lin Cai

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


In IEEE 802.11 WLANs, packet losses may be due to buffer overflow, transmission errors, or collisions. Therefore, the performance of TCP-Friendly Rate Control (TFRC) in IEEE 802.11 WLANs largely depends on its ability to differentiate packet losses resulting from network congestion (due to buffer overflow and collisions) and those from transmission errors. In this paper, an enhanced TFRC (E-TFRC) protocol is proposed to detect and identify the cause of packet loss events through a novel two-phase loss differentiation algorithm (TP-LDA). The packet losses due to buffer overflow and those due to failed transmissions in WLANs are first differentiated. For failed transmissions, the fraction of those due to collisions is obtained with the assistance of the lower layer. By employing TP-LDA, only the packet losses due to buffer overflow and collisions are notified to the sender for appropriate flow and congestion control. To quantify the performance of TFRC and E-TFRC over WLANs, a continuous-time Markov chain based on a new WLAN link model is developed by considering both collisions and transmission errors. Analytical and simulation results demonstrate that, with appropriate loss differentiation, E-TFRC can achieve higher throughput than TFRC in WLANs with different channel profiles.

Original languageEnglish
Pages (from-to)4164-4175
Number of pages12
JournalIEEE Transactions on Wireless Communications
Issue number11
Publication statusPublished - 2007 Nov

Bibliographical note

Funding Information:
Manuscript received May 23, 2006; revised November 1, 2006 and February 2, 2007; accepted February 24, 2007. The associate editor coordinating the review of this paper and approving it for publication was W. Liao. This work has been supported in part by a Strategic Grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada under Grant No. STPGP 257682 and in part by the Korea Research Foundation Grant No. M01-2005-000-10073-0.


  • Effective throughput
  • IEEE 802.11 WLANs
  • TCP-friendly rate control
  • Two-phase loss differentiation algorithm
  • WLAN link model

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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