1. Physical Layer Model of the Impact of Bluetooth on IEEE 802.11b
July 2000
doc.: IEEE /220r0
July 2000
IEEE P Working Group for Wireless Personal Area NetworksTM
Physical Layer Model of the Impact of Bluetooth on IEEE b
Peter J. Voltz, Polytechnic University
Peter J. Voltz, Polytechnic University

2. Bluetooth interferer modeled as tone jammer
July 2000
doc.: IEEE /220r0
July 2000
Physical Layer Simulation Model For Impact of Bluetooth Interferer on 11Mbps Receiver
Bluetooth interferer modeled as tone jammer
Performance of Receiver depends on the following:
Signal to Interference Ratio (SIR)
Signal to Background Noise Ratio
Frequency of Bluetooth Interferer
Multipath Structure
Receiver Processing
Peter J. Voltz, Polytechnic University
Peter J. Voltz, Polytechnic University

3. Processing Options Basic Processing (BP) BP + MF
July 2000
Processing Options
Basic Processing (BP)
BP + MF
Matched Filter (MF) for collecting multipath energy
BP + MF + EQ
Equalizer (EQ) to correct for Intersymbol Interference (ISI)
Peter J. Voltz, Polytechnic University

4. Tapped Delay Line Channel Model
July 2000
Tapped Delay Line Channel Model
Channel Impulse Response
Peter J. Voltz, Polytechnic University

5. Pick Largest Pick Largest D-QPSK D-QPSK Channel Channel Matched Filter
July 2000
Channel
Matched Filter
Channel
Pick
Largest
Pick
Largest
D-QPSK
D-QPSK
Peter J. Voltz, Polytechnic University

6. Communication System Analysis
July 2000
Communication System Analysis
Peter J. Voltz, Polytechnic University

7. July 2000
Peter J. Voltz, Polytechnic University

8. Output of Receiver due to 802.11 input
July 2000
Output of Receiver due to input
Where
Peter J. Voltz, Polytechnic University

9. and the channel is clear, then and
July 2000
Note that if
is time limited to
Seconds,
and the channel is clear, then
and
Which is the cross correlation between the receivers reference
codeword and the particular codeword being received, times the
phase factor which carries 2 bits.
When a multipath channel is present, the non-zero values of
for
cause intersymbol interference.
Peter J. Voltz, Polytechnic University

10. Response to Interference
July 2000
Response to Interference
Frequency offset,
, has two effects
Peter J. Voltz, Polytechnic University

11. 1. Effective amplitude of interferer is multiplied by
July 2000
1. Effective amplitude of interferer is multiplied by .
2. The discrete sine wave,
, is correlated with
the 64 CCK codewords and contributes to outputs.
Peter J. Voltz, Polytechnic University

12. July 2000
Simulation Results for three sample channels. Bluetooth Interferer at Band Center. Eb/No = 20 dB for white noise.
Peter J. Voltz, Polytechnic University

13. Effect of frequency offset due to digital sine wave correlation effect
July 2000
Effect of frequency offset due to digital sine wave correlation effect
Peter J. Voltz, Polytechnic University

14. Effect of frequency offset due to digital sine wave correlation effect
July 2000
Effect of frequency offset due to digital sine wave correlation effect
Peter J. Voltz, Polytechnic University

15. Effect of frequency offset due to digital sine wave correlation effect
July 2000
Effect of frequency offset due to digital sine wave correlation effect
Peter J. Voltz, Polytechnic University

16. July 2000
Conclusions
We have modeled the b Receiver except for the Equalizer.
Without the equalizer the effect of interference is heavily dependent on the actual channel model.
At 10-4 the SIR varies from about 6 dB to about 18 dB
Peter J. Voltz, Polytechnic University

17. Next Steps Add the Equalizer into the model
July 2000
Next Steps
Add the Equalizer into the model
See if the variation due to the channel is reduced
Develop a formula for the Symbol Error Rate (SER) as a function of SIR.
Feed that (SER) formula into the MAC model.
Peter J. Voltz, Polytechnic University