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Inquiry and Paging for Bluetooth Piconet and Scatternet Formation in NS

Inquiry and Paging for Bluetooth Piconet and Scatternet Formation in NS. Denis Perelyubskiy Vadim Olshansky Vitaliy Dykhne. Project Overview. Implementation of Bluetooth Inquiry and Paging procedures in ns-2 network simulator based on Bluetooth Standard version 1.0b/1.1. Project Goals.

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Inquiry and Paging for Bluetooth Piconet and Scatternet Formation in NS

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  1. Inquiry and Paging for Bluetooth Piconet and Scatternet Formation in NS Denis Perelyubskiy Vadim Olshansky Vitaliy Dykhne

  2. Project Overview • Implementation of Bluetooth Inquiry and Paging procedures in ns-2 network simulator based on Bluetooth Standard version 1.0b/1.1

  3. Project Goals • Implement Link Controller state machine • Implement Frequency Hopping • Simulate node discovery and connection setup to evaluate performance of Bluetooth technology in various scenarios

  4. Link Controller State Machine

  5. Accomplishments • Done • Frequency Hopping • Inquiry Procedure • Paging Procedure (pending resolution of several serious issues) • Limited Performance Analysis of Inquiry Procedure • 3000 lines of code

  6. Accomplishments (cont) • Not Done • Scatternet Formation • Paging Procedure Performance Analysis

  7. Problems Encountered • Our biggest problem is the standard: • General and vague • Insufficiently precise on critical issues such as frequency hopping • Changed recently

  8. Example of a specific problem • Master needs to operate in both transmit and receive modes while waiting for an ID packet from the bluetooth slave • In page mode “the RX hops are selected according to the page_response hopping sequence” (BT 1.1, 3rd paragraph, page 98) • X control input to the frequency hopping computation is Xprm =[CLKE*16-12+ Koffset* + (CLKE*4-2,0-CLKE*16-12) mod 16 + N]mod32 • here, CLKE* is the “frozen” clock, and k-offset is a “frozen” offset. “The values are frozen when the slave ID packet is received” (section 11.3.3.2 of the BT 1.1 standard)

  9. Example of a specific problem(contd) • Problem: if the ID packet has not been received from the slave yet, we will not have frozen clock/offset values — what do we do?

  10. Implications of the problem • While we can compute some kind of hopping sequences for both nodes involved, it takes them a very long time to randezvous, which hints at the wrong values of inputs to the frequency-hopping function • Using random sequences of some sort during connection establishment is difficult

  11. On a brighter side... • We did implement and test the frequency hop computation • validated using sample data at the end of the specification • this means that our function works utilizing “garbage-in-garbage-out” principle: given good inputs, it will produce proper output ; this means to fix 99% of our problems, we just need to clarify the inputs to the function at several controversial states.

  12. Some Simulation Results

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