1. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Mutlipath Energy Collection in Multi-Band UWB Receivers] Date Submitted: [ 8 May, 2003] Source: [Charles Razzell, Dagnachew Birru, Bill Redman-White] Company [Philips] Address [1109 McKay Drive, San Jose, 95131, California, USA] Voice:[+1 408-474-7243], FAX: [+1 408-474-5343], E-Mail:[charles.razzell@philips.com] Re: [] Abstract:[This document discusses and evaluates multipath energy collection in the context of multi-band receivers. Various options are considered related to PRF, modulation order and number of parallel receive paths.] Purpose:[Consider this when comparing the relative merits of a multi-band PHY against other options.] Notice:This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release:The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

2. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 2 Energy Collection in Multi-band UWB Receivers A technical contribution to the multi-band discussion

3. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 3 Scope of the problem UWB channel models are highly dispersive relative to the pulse widths typically considered. A channel matched filter would require an average of 132 taps at 6GHz to collect 85% of the energy in CM4. Good performance requires that we don’t discard a significant proportion of the available energy. A balance between hardware complexity and energy collection/performance is sought.

4. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 4 How Many Taps are Needed? CM1CM2CM3CM4 NP 85% (BW=6GHz) 28.244.573.2132.4 NP 85% (BW=264MHz) 1.241.963.225.8 NP 85%  Number of Paths needed for 85% energy

5. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 5 Cumulative Distribution Function of # significant RAKE fingers (CM2) 11.21.41.61.822.22.42.6 0 10 20 30 40 50 60 70 80 90 100 number of significant chips (3.79ns/chip) Cumulative number of channels CM2: number of chips to capture 85% energy 90% of channels require less than 2.3 RAKE fingers

6. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 6 Cumulative Distribution Function of # significant RAKE fingers (CM3) 1.522.533.544.555.5 0 10 20 30 40 50 60 70 80 90 100 Cumulative number of channels number of significant chips (3.79ns/chip) CM3: number of chips to capture 85% energy 90% of channels require less than 4 RAKE fingers

7. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 7 Cumulative Distribution Function of # significant RAKE fingers (CM4) 3.544.555.566.577.58 0 10 20 30 40 50 60 70 80 90 100 number of significant chips (3.79ns/chip) Cumulative number of channels CM4: number of chips to capture 85% energy 90% of channels require less than 7 RAKE fingers

8. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 8 Local Oscillator Requirements (1) Oscillator must switch frequency in time slot << 3.8ns Multi-frequency generator is a feasible approach

9. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 9 Local Oscillator Requirements (2)

10. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 10 Implementation choice, for higher performance, employs 2 receiver paths 2 oscillator frequencies needed at same time Parallel Receiver Architecture Estimated RF Area ~ 2.5mm 2 in 0.25  m SiGe BiCMOS Estimated Digital Area ~ 7mm 2 in 0.12  m CMOS

11. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 11 Number of feasible RAKE fingers Fully Serial Rx Parallel (2) Rx (see previous slide) Parallel (3) Rx (extension of previous slide) Half PRF (110Mbps) 246 Full PRF (200Mbps) 123

12. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 12 Simulation Results Evaluate the need for energy collection –Serial and parallel receivers and multiple RAKE fingers Parameters: –132 MHz PRF for QPSK (“half PRF”) –264 MHz PRF for BPSK (“full PRF”) –Rate ½ convolutional code –7 Bands spaced at 440 MHz –Interleaver after convolutional encoder to further spread the information bits across multiple bands

13. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 13 BER for CM4, one finger, one path The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

14. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 14 BER for CM4, two fingers, one path The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

15. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 15 BER for CM4, two fingers per path, parallel receiver paths The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

16. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 16 BER for CM4, four fingers per path, parallel receiver paths The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

17. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 17 BPSK BER for CM4, one finger, one path The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

18. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 18 BPSK BER for CM4, one finger per path, parallel receiver paths The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

19. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 19 BPSK BER for CM4, two fingers per path, parallel receiver paths The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

20. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 20 BPSK BER for CM4, four fingers per path, parallel receiver paths The multipath curves are the average of the best 45 from 50 channel realizations. Eb is energy per uncoded bit

21. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 21 Modulation Schemes and PRF Options to use BPSK and QPSK Which modulation is the best? BPSK QPSK

22. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 22 Modulation Schemes and PRF (cnt’d) QPSK lowers PRF –Improved multipath performance via Energy collection Reducing ISI –Improved piconet performance –But requires more accurate phase reference BPSK increases PRF –Lower multipath performance ISI performance could be improved via equalization Efficient energy collection is impossible at 110MB/s without using parallel receivers (or reducing data rate) –But can tolerate less accurate phase reference For identical data rates

23. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 23 Modulation Schemes and PRF (cnt’d) Can achieve this with serial Rx at 110Mbps

24. doc.: IEEE 802.15-03/210r0 Submission May, 2003 C. Razzell, PhilipsSlide 24 Discussion Simulations have shown that at least 2 RAKE fingers are needed to obtain a reasonable link budget in CM4. This is compatible with a fully serial receiver implementation at 110Mbps (half PRF, QPSK). The number of receiver branches can be an implementation choice, depending on the robustness and data rates targeted. Further results need to be collected to find the optimum balance of complexity vs. performance.