1. Modeling Channel Conflict Probabilities between IEEE 802.15 based WPANs Ling-Jyh Chen 1, Tony Sun 2, and Mario Gerla 2 1 Institute of Information Science, Academia Sinica 2 Dept. of Computer Science, University of California at Los Angeles

2. Outline Introduction Overview of WPAN standards Coexistence issues Analysis Conclusion

3. Introduction With the increasingly deployed WPAN devices, channel conflict has become very frequent and severe. Previous studies focus on modeling packet/frame error rates and/or measuring data throughput when channel conflicts are present. In this paper, we study the prob of channel conflicts when multiple WPAN devices coexist.

4. Channel allocation of IEEE 802.15 standards IEEE 802.15.1 (Bluetooth) IEEE 802.15.4

5. Channel allocation of IEEE 802.15 standards IEEE 802.15.3

6. Channel allocation of IEEE 802.11/15 standards

7. Frequency Hopping in Bluetooth Each time, the FH kernel selects a segment of 64 adjacent channels, and then hops to 32 of them without repetition in a random order Next, a different 32-hop sequence is chosen from another segment of 64 adjacent channels

8. Coexistence issues coexistence: The ability of one system to perform a task in a given shared environment where other systems have an ability to perform their tasks and may or may not be using the same set of rules. IEEE 802.15.2: Coexistence of Wireless Personal Area Networks with Other Wireless Devices Operating in Unlicensed Frequency Bands

9. Analysis 4 cases One 802.15.1 + multiple 802.15.3 One 802.15.1 + multiple 802.15.4 One 802.15.3 + multiple 802.15.4 One 802.15.4 + multiple 802.15.3

10. Analysis 1: one 15.1 & multiple 15.3 P[R=r]: the prob that there are r conflicting channels in the selected segment of 64 adjacent channels P[K=k|R=r]: the prob that, given r conflicted channels in the 64 adjacent channels, k out of the selected 32 hop sequence are conflicted S=1 : the selected channel (out of the 32 hop sequence) is conflicted

11. Analysis 1: one 15.1 & multiple 15.3 Case 1: n=1

12. Analysis 1: one 15.1 & multiple 15.3 Case 2: n=2

13. Analysis 1: one 15.1 & multiple 15.3 Case 3: n=3

14. Analysis 2: one 15.1 & multiple 15.4 Case 1: n=1 Case 2: n>1 Use Monte Carlo simulation method

15. Analysis 2: one 15.1 & multiple 15.4

16. Analysis 3: one 15.3 & multiple 15.4 Pigeonhole Principle: one 15.3 can coexist with at most 12 15.4 networks (i.e., 0<=n<=12)

17. Analysis 3: one 15.3 & multiple 15.4

18. Analysis 4: one 15.4 & multiple 15.3 Case 1: 15.4 operates on one of the four non-overlapped channels (i.e., P_good = 1) Case 2: 15.4 operates on one of the overlapped channels (i.e., P_good = (3-n)/3)

19. Analysis 4: one 15.4 & multiple 15.3

20. Conclusion IEEE 802.15.1 coexists well with 15.3 and 15.4 networks (i.e., due to FHSS) IEEE 802.15.3 and 802.15.4 have coexistence problem. The analytical results need to consider SNR and other issues in order to obtain packet/frame/bit error rate.