5th International ICST Conference on Wireless Internet

Research Article

Voice Adaptive Gateway Pacer for wireless multihop networks

Download112 downloads
  • @INPROCEEDINGS{10.4108/ICST.WICON2010.8537,
        author={Dragoș Niculescu and Kyungtae Kim and Sampath Rangarajan and Sangjin Hong},
        title={Voice Adaptive Gateway Pacer for wireless multihop networks},
        proceedings={5th International ICST Conference on Wireless Internet},
        keywords={Adaptive control Bandwidth Communication system control Communication system traffic control Interference Programmable control Protection Spread spectrum communication Telecommunication traffic Traffic control},
  • Dragoș Niculescu
    Kyungtae Kim
    Sampath Rangarajan
    Sangjin Hong
    Year: 2010
    Voice Adaptive Gateway Pacer for wireless multihop networks
    DOI: 10.4108/ICST.WICON2010.8537
Dragoș Niculescu1,a,b, Kyungtae Kim2, Sampath Rangarajan2, Sangjin Hong3
  • 1: ETTI, University Politehnica of Bucharest
  • 2: NEC Laboratories America
  • 3: ECE, Stony Brook University
  • a: partly based on results obtained while first author was employed by NEC
  • b: Laboratories America.


When supporting both voice and TCP in a wireless multihop network, there are two conflicting goals: to protect the VoIP traffic, and to completely utilize the remaining capacity for TCP. We investigate the interaction between these two popular categories of traffic and find that conventional solution approaches, such as enhanced TCP variants, priority queues, bandwidth limitation, and traffic shaping do not always achieve the goals. TCP and VoIP traffic does not easily coexist because of TCP aggressiveness and data burstiness, and the self-interference nature of multihop traffic. We found that enhanced TCP variants (Reno, Vegas, C-TCP, CUBIC, Westwood) fail to coexist with VoIP in the wireless multihop scenarios. Surprisingly, even priority schemes, including those built into the MAC such as RTS/CTS or 802.11e, generally cannot protect voice, as they do not account for the interference outside communication range. We present VAGP (Voice Adaptive Gateway Pacer) - an adaptive bandwidth control algorithm at the access gateway, that dynamically paces wired-to-wireless TCP data flows based on VoIP traffic status. VAGP continuously monitors the quality of VoIP flows at the gateway and controls the bandwidth used by TCP flows before entering the wireless multihop. To also maintain utilization and TCP performance, VAGP employs TCP specific mechanisms that suppress certain retransmissions across the wireless multihop. Compared to previous proposals for improving TCP over wireless multihop, we show that VAGP retains the end-to-end semantics of TCP, does not require modifications of endpoints, and works in a variety of conditions: different TCP variants, multiple flows, internet delays, different patterns of interference, different multihop topologies, different traffic patterns.