Submission Title: [Frequency Plan and PRF Proposal for TG4a] Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [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. TG4a
Impulse Radio-BPSK VPeak TC PRI TG4a
Minimum PRF Requirements BW = 520 MHz Technology CMOS 90nm 2.5 Vpp CMOS 90nm 1.0 Vpp TChip (nsec) 1.9 BW (MHz) 520 VPeak (v) 1.25 0.5 PAve (dBm) -14 -9.4 PPeak (dBm) 12 4 PRF (MHz) @ VPeak 1.3 8 BW = 1560 Technology CMOS 90nm 2.5 Vpp CMOS 90nm 1.0 Vpp TChip (nsec) 1.9 BW (MHz) 1560 VPeak (v) 1.25 0.5 PAve (dBm) -14 -9.4 PPeak (dBm) 12 4 PRF (MHz) @ VPeak 11.5 72 TG4a
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 receiver 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. TG4a
PLL Reference Diagram fX fComp output fX fcomp 26 2 13 19.2 24 0.8 12 Oscillator Reference Divider (R) output XTAL Phase Det. LPF VCO Divider, N fX (MHZ) R (MHz) fcomp 26 2 13 19.2 24 0.8 12 1 TG4a
Frequency Plan Band No. Bandwidth (MHz) Low Freq. Center Freq. High Freq. 1 520 3224 3484 3744 2 4004 4264 3 4524 4784 Band No. 4 1 2 3 3 3.25 3.5 3.75 4 4.25 4.5 4.75 5 GHz Note: This plan has equal margins to 3.1 GHz & 4.9 GHz frequencies TG4a
The PRF The basic recommended PRF is 13 MHz. A PRF of 26 MHz is also supported. These PRFs can be generated from the center frequencies of the supported bands. For example, a PRF of 13 MHz may be obtained by dividing the center frequencies by 268, 308, and 348 for bands 1, 2, and 3 respectively. It is worth mentioning that ranging precision stays unchanged when using PRFs of 13 MHz and 26 MHz (or even higher PRFs) as the effective pulse width is only affected by bandwidth not the PRF. TG4a