C2TCP: A Flexible Cellular TCP to Meet Stringent Delay Requirements

Soheil Abbasloo, Yang Xu, H. Jonathan Chao

Research output: Contribution to journalArticlepeer-review


Since, current widely available network protocols/ systems are mainly throughput-oriented designs, meeting stringent delay requirements of new applications such as virtual reality and vehicle-to-vehicle communications on cellular network requires new network protocol/system designs. C2TCP is an effort toward that new design direction. C2TCP is inspired by in-network active queue management designs such as RED and CoDel and motivated by lack of a flexible end-to-end approach which can adapt itself to different applications' QoS requirements without modifying any network devices. It copes with unique challenges in cellular networks for achieving ultra-low latency (including highly variable channels, deep per-user buffers, self-inflicted queuing delays, and radio uplink/downlink scheduling delays) and intends to satisfy stringent delay requirements of different applications while maximizing the throughput. C2TCP works on top of classic throughput-oriented TCP and accommodates various target delays without requiring any channel prediction, network state profiling, or complicated rate adjustment mechanisms. We have evaluated C2TCP in both real-world environment and extensive trace-based emulations and compared its performance with different TCP variants and state-of-the-art schemes including PCC-Vivace, Google's BBR, Verus, Sprout, TCP Westwood, and Cubic. Results show that C2TCP outperforms all these schemes and achieves lower average delay, jitter, and 95th percentile delay for packets.

Original languageEnglish (US)
Article number8638955
Pages (from-to)918-932
Number of pages15
JournalIEEE Journal on Selected Areas in Communications
Issue number4
StatePublished - Apr 2019


  • TCP
  • Ultra low latency
  • cellular networks
  • congestion control
  • controlled delay
  • quality of service

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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