WiCop: Engineering WiFi temporal white-spaces for safe operations of Wireless Body Area Networks in medical applications

Yufei Wang, Qixin Wang, Zheng Zeng, Guanbo Zheng, Rong Zheng

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

39 Citations (Scopus)


ZigBee and other wireless technologies operating in the (2.4GHz) ISM band are being applied in Wireless Body Area Networks (WBAN) for many medical applications. However, these low duty cycle, low power, and low data rate medical WBANs suffer from WiFi co-channel interferences. WiFi interference can lead to longer latency and higher packet losses in WBANs, which can be particularly harmful to safety-critical applications with stringent temporal requirements. Existing solutions to WiFi- WBAN coexistence either require modifications to WiFi or WBAN devices, or have limited applicability. In this paper, by exploiting the Clear Channel Assessment (CCA) mechanisms in WiFi devices, we propose a novel policing framework, WiCop, that can effectively control the temporal white-spaces between WiFi transmissions. Specifically, the WiCop Fake-PHY-Header policing strategy uses a fake WiFi PHY preamble-header broadcast to mute other WiFi interferers for the duration of WBAN active interval; while the WiCop DSSS-Nulling policing strategy uses repeated WiFi PHY preamble (with its spectrum side lobe nulled by a band-pass filter) to mute other WiFi interferers throughout the duration of WBAN active interval. The resulted WiFi temporal white-spaces can be utilized for delivering low duty cycle WBAN traffic. We have implemented and validated WiCop on SORA, a software defined radio platform. Experiments show that with the assistance of the proposed WiCop policing schemes, the packet reception rate of a ZigBee-based WBAN can increase by up to 43.8% in presence of a busy WiFi interferer.
Original languageEnglish
Title of host publicationProceedings - 2011 32nd IEEE Real-Time Systems Symposium, RTSS 2011
Number of pages10
Publication statusPublished - 1 Dec 2011
Event2011 32nd IEEE Real-Time Systems Symposium, RTSS 2011 - Vienna, Austria
Duration: 29 Nov 20112 Dec 2011


Conference2011 32nd IEEE Real-Time Systems Symposium, RTSS 2011


  • Coexistence
  • Reliability
  • Safety
  • WBAN
  • WiFi

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture
  • Computer Networks and Communications

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