1 / 26

Enabling Co-channel Coexistence of 802.22 and 802.11af Systems in TV White Spaces

Enabling Co-channel Coexistence of 802.22 and 802.11af Systems in TV White Spaces. Xiaojun Feng , Qian Zhang, and Bo Li Hong Kong University of Science and Technology IEEE ICC 2013. Outline. Background Coexistence Problem Busy-tone based Coexistence Framework Simulation Results

zorina
Download Presentation

Enabling Co-channel Coexistence of 802.22 and 802.11af Systems in TV White Spaces

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Enabling Co-channel Coexistence of 802.22 and 802.11af Systems in TV White Spaces XiaojunFeng, Qian Zhang, and Bo Li Hong Kong University of Science and Technology IEEE ICC 2013

  2. Outline • Background • Coexistence Problem • Busy-tone based Coexistence Framework • Simulation Results • Conclusions

  3. TV White Spaces • TV White Spaces • Free TV channels after Analog to Digital Transition • FCC rules • Sep. 2010

  4. Standards • IEEE 802.22 • Target: Wireless Regional Area Networks (WRAN) • MAC: TDMA-like • Power: 4W (36dBm) • Sensitivity: -97 dBm. • Range: up to 100 km

  5. Standards • IEEE 802.11af • Target: Wireless Local Area Networks (WLAN) • MAC: CSMA • Power: 100mW (20dBm) • Sensitivity: -64 dBm. • Range: about 1km Source: MSR

  6. Heterogeneities • 802.22 and 802.11af are different at almost all levels in the protocol stack. • Comparison of some key specifications

  7. Outline • Background • Coexistence Problem • Busy-tone based Coexistence Framework • Simulation Results • Conclusions

  8. Coexistence Problem • Challenge 1: Hidden Terminal to 802.22 • Low sensitivity of 802.11af • 802.11af cannot detect 802.22 and becomes a hidden terminal • Challenge 2: Exposed Terminal to 802.11af • High transmission power of 802.22 and TDMA MAC • 802.11af can be badly blocked

  9. Illustrated Example • A: 802.22 Base Station (BS) • B: 802.22 CPE • C: 802.11af access point (AP) • D: 802.11af client device

  10. Illustrated Example • Challenge 1: Hidden Terminal to 802.22 • Distance between A and B/C: • Distance between B and C/D: • Interference from C to B: • Signal from A to B:

  11. Illustrated Example • Challenge 2: Exposed Terminal to 802.11af • Distance between B and C/D is • Distance from C to D is • Interference from B to D: • Signal from C to D:

  12. Existing Solutions • 802.19 protocol • Centralized control • Assume devices have common interface • [7] X. Zhang and K. Shin, “Enabling Coexistence of Heterogeneous Wireless Systems: Case for Zigbee and Wi-Fi”, in ACM MobiHoc 2011. • [8] H. Rahul, N. Kushman, D. Katabi, C. Sodini, and F. Edalat, “Learning to Share: Narrowband-Friendly Wideband Networks”, in ACM MobiCom 2008.

  13. Our New Observations • 802.22 node has two antennas in both BS and CPE • TX/RX antenna: • BS: omni-directional antenna • CPE: directional antenna • Sensing antenna: • Omni-directional • We can leverage the sensing antenna for busy tone

  14. Outline • Background • Coexistence Problem • Busy-tone based Coexistence Framework • Simulation Results • Conclusions

  15. Basic Idea of Busy-tone • Let the sensing antenna at the 802.22 CPE send out busy-tone signal with known pattern with 100 mW power. • Self-interference cancellation at the 802.22 CPE

  16. Busy-tone Design • Busy-tone Feasibility • 70 dB self-interference cancellation can be achieved in the literature • Busy-tone Duration

  17. Busy-tone Design • Exposed CPE detection • Leverage the busy-tone pattern at the CPE. • First weak patterned busy-tone signal • Then strong non-patterned 802.22 signal

  18. Outline • Background • Coexistence Problem • Busy-tone based Coexistence Framework • Simulation Results • Conclusions

  19. Simulation Setup • The distance between the 802.22 BS and CPE: 5km~15km • We randomly generate one 802.11af AP and one 802.11af client within the carrier sense range of the busy-tone • Results are averaged with 10000 randomly generated topologies.

  20. Simulation Scenarios • 802.11 only • Only the 802.11af network occupying the entire channel • 802.22 only • Only the 802.22 network occupying the entire channel • Coexistence without busy-tone • Coexistence with busy-tone

  21. Impact of the Busy-tone Scheme on 802.22 Throughput

  22. Impact of the Busy-tone Scheme on 802.11af Throughput

  23. Impact of the Busy-tone Scheme on the Total Throughput

  24. Outline • Background • Coexistence Problem • Busy-tone based Coexistence Framework • Simulation Results • Conclusions

  25. Conclusions • We investigate the coexistence scenario and identify the coexistence challenges between the 802.22 and the 802.11af networks. • We proposed a busy-tone based scheme to enable the co-channel coexistence of the two systems. • Through extensive simulation, we show that the spectrum utilization can be increased with the proposed scheme.

  26. Thanks! Enabling Co-channel Coexistence of 802.22 and 802.11af Systems in TV White Spaces XiaojunFeng xfeng@cse.ust.hk

More Related