Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Revised Frequency Plan and PRF Proposal for TG4a] Date Submitted: [27 April 2005] Source: [Ismail Lakkis & Saeid Safavi, Wideband Access Inc.] Contact: Saeid Safavi. Voice:[+1 858 642 9114, E-Mail: ssafavi@widebandaccess.com] Abstract: [Minimum required PRF for CMOS DS-UWB radios] Purpose: [Clarification of relationship between minimum PRF and maximum allowed voltage level in UWB IR] 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. PRI VPeak TC Impulse Radio-BPSK/Ternary

3. Minimum PRF Requirements

4. Benefits of Low PRF over High PRF • A Low PRF system has a lower implementation cost when compared to a high PRF system • Overall required RF/IF gain is lower for a Low PRF system. For example a 12 MHz PRF would reduce the receiver dynamic range by 7 dB when compared to a 60 MHz PRF • The ADC would run at 12 MHz instead of 60 MHz in the above example and the entire digital processor would run at a lower clock reducing the power by a factor of 5 in CMOS • Acquisition is easier to implement since with Lower PRF the sync matched filter is much smaller: • If a 12 MHz system requires a 64 pulses sync pattern, a 60 MHz system would require a sync of 320 pulses to achieve same SNR. • Since Energy per pulse is higher (7 dB in the above example), a non-coherent receiver would perform better.

5. PLL Reference Diagram fX fComp Oscillator Reference Divider (R) output XTAL Phase Det. LPF VCO Divider, N

6. Frequency Plan Band No. 4 111 MHz 207 MHz 1 2 3 3 4 5 GHz 3.25 3.5 3.75 4.25 4.5 4.75 Note: This plan has almost double margin to 4.9 GHz as compared to 3.1 GHz

7. The PRF • To satisfy other proposer’s preferences a wide range of PRFs (total of 3) are supported which are compliant with the Harmonic Chip rate requirements. • The basic recommended PRF is 15.4375MHz. • PRFs of 30.875 MHz and 61.75 MHz are also supported. • These PRFs can be generated from the center frequencies of the supported bands. For example, a PRF of 61.75 MHz may be obtained by dividing the center frequencies by 8x7, 8x8 , and 8x9 for bands 1, 2, and 3 respectively. This is further illustrated in the next slide.

8. PRF Flexibility • Example of the flexibility of the new PRF scheme compared to Wisair’s proposal for generation of the PRF of above 60 MHz Wisair’s Proposal Wideband Access’ Proposal Center Freq. (MHz) PRF (MHz) Center Freq. (MHz) PRF (MHz) Harmonic Ratio Harmonic Ratio 3952 61.75 3960 66 64 4x3x5 3458 61.75 3432 66 8x7 4x13 4446 61.75 4488 66 8x3x3 4x17 Prime Factors: 7, 3 Prime Factors: 17, 13, 5, 3

9. Frequency Plan Details

10. Margin to 3.1 and 4.9 • The 3.1 GHz corner filtering is mandatory (FCC requirement), whereas, the rejection at 4.9 is desirable. • For an impulse radio using a pulser (no mixer), the only required filtering in the chain is the RF BPF. Consequently, the BPF is responsible for the -10 dB (at least) rejection at 3.1 GHz. Hence a relatively safe margin at 3.1 GHz is required (as supported in this proposal). • In any case, there is a safe margin to 4.9 GHz in our new proposal.

11. Benefits of the Frequency Plan • Support of a wide range of PRFs . These PRFs allow peak power margins of 4.5-8 dB. • Support of a range of Xtals (12,13,9.6, etc.) • Enough margin to 3.1 & 4.9 GHz (to meet the FCC requirements and coexistence with WLAN). • The proposed PRFs can be easily generated using mainly power of 2 divisions in the first stages, while maintaining small division factors at last stages (3,7).