Modeling Channel Conflict Modeling Channel Conflict Probabilities between IEEE Probabilities between IEEE

802.11b and 802.11b and IEEE 802.15.1 NetworksIEEE 802.15.1 Networks

Ling-Jyh Chen and Ting-Kai HuangLing-Jyh Chen and Ting-Kai HuangInstitute of Information Science, Academia SinicaInstitute of Information Science, Academia Sinica

Introduction Overview of WLAN & WPAN

standards Coexistence issues Analysis Conclusion

OutlineOutline

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 WPAN/WLAN devices coexist.

IntroductionIntroduction

Channel allocation of IEEE Channel allocation of IEEE 802.11/15 standards802.11/15 standards

IEEE 802.11b

IEEE 802.15.1

Channel allocation of IEEE Channel allocation of IEEE 802.15 standards802.15 standards

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

Coexistence issuesCoexistence issues

3 cases One 802.15.1 + One 802.11b One 802.15.1 + Two 802.11b One 802.15.1 + Three 802.11b

AnalysisAnalysis

Hopping cycle (32 slots) is defined as: FH kernel selects a segment of 64 adjacent channels out of 79, and then 32 of them are used one at a time without repetition in a random order

Next, a different 32-hop sequence is chosen from another segment of 64 adjacent channels

32 of them are chosen

Frequency Hopping in Frequency Hopping in BluetoothBluetooth

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

Analysis 1: one 15.1 & one Analysis 1: one 15.1 & one 11.b11.b

Analysis 1: one 15.1 & one Analysis 1: one 15.1 & one 11.b11.b

Analysis 2: one 15.1 & two Analysis 2: one 15.1 & two 11.b11.b

Analysis 3: one 15.1 & 3 Analysis 3: one 15.1 & 3 11.b11.b

The channel conflict probability increases linearly as the number of IEEE 802.11b networks increases.

The proposed model is simple and applicable to calculating channel conflict probabilities of other wireless technologies.

Future work is to take the error models (e.g., SNR vs PER) into account, and extend our analysis to model the packet/frame error rates for multiple coexisting WPAN/WLAN networks.

ConclusionConclusion

Thanks!Thanks!

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