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: [TG4a Frequency Band Proposal] Date Submitted: [May 2004] Source: [Matt Welborn] Company [Freescale Semiconductor, Inc] Address [8133 Leesburg Pike, Vienna VA 22182] Voice:[703-269-3000], FAX: [], E-Mail:[matt.welborn @ freescale.com] Re: [Response to Call for Proposals] Abstract: [This document describes a frequency band proposal for the TG4a baseline draft standard.] Purpose: [Proposal Presentation for the IEEE802.15.4a standard.] 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. Welborn (Freescale)

2. Objectives • Propose a frequency band plan in accordance with the TG4a baseline draft standard merger document • Summary of requirements for band plan, omitting N/A bullets • Sub-banding: • Center of three bands is mandatory, Other two optional • Wider bandwidth (1.5 GHz+) concentric with center band is optional • CDMA within frequency bands • Harmonic chip rate – integer relationship between center frequency and chip rate • Mandatory • ~500 center band (AM of 3.1-4.9 is 3.975, GM of 3.1-4.9 is 3.877) • Center band frequency is TBD, but must be in [3.85 to 4.05] • Optional • 2 additional 500 MHz bands for FDM – center frequencies TBD • Wideband concentric with center specified above • Sub-GHz band • … • Add specific optional band > 6 GHz with guaranteed >1.5GHz BW • Support mode for higher data rates (few to 10 Mbps) • Other issues • … • Multiple (2-few) PRF in band Welborn (Freescale)

3. Advantages • Meets requirements of TG4a baseline draft • Uses non-uniform bandwidths for mandatory and two optional narrow bands • Allows same pass-band pulse shape to be used in each band (simplifies pulse generation) • Provides more uniform performance for each of three narrow bands • PRF would also scale with changing center frequency to allow fixed (integer) relationship between center frequency, BW and chip rate • All frequencies (chip rates, pulse burst rates, center frequencies) can be integer multiple of a 13 MHz reference Welborn (Freescale)

4. Signal Design Objectives • Technical Objectives: • Support for low-complexity, non-coherent receiver architectures (energy detect and energy collector) • Support for higher-complexity coherent architectures • Support for ranging for both architectures (TOA and TDOA) • Support for data rates as high as 7 to 14 Mbps Welborn (Freescale)

5. Frequency Plan Band No. 4 1 2 3 3 4 5 GHz 3.25 3.5 3.75 4.25 4.5 4.75 Welborn (Freescale)

6. Higher Band Frequency Plan Band No. 8 5 6 7 6 8 10 GHz 6.5 7 7.5 8.5 9 9.5 Welborn (Freescale)

7. Main Features of proposed system Proposal main features: • Impulse-radio based (pulse-shape independent) • Common synchronisation / ranging preamble signaling for different classes of nodes / type of receivers (coherent / noncoherent) • Band Plan based on multiple 500+ MHz bands (center band mandatory) and optional wider bandwidth (~1.5 GHz+) concentric with center band • Robustness against SOP interference • Robustness against other in-band interference • Scalability to trade-off complexity/performance Welborn (Freescale)

8. Details of proposed system • Proposed waveform is similar to others proposed by Samsung, Mitsubishi, Time Domain and I2R • Should make it easier to get group support • Data symbols are transmitted using short sequences of pulses with “silent” periods • Allows coherent reception and also “energy collector” or “energy detector” architecture as well • Should support implementing low-power, low-complexity devices and still provide good performance in multipath Welborn (Freescale)

9. Signals already proposed by Others (Mitsubishi, TDC, I2R, etc) One Bit Optionally Empty Always Empty Always Empty 32 32 32 Next potential active time 32 chip sequence The Other Bit Optionally Empty Always Empty Always Empty 32 32 32 Only 160 ns of channel multipath tolerance in this case. Next potential active time 32 chip times We transmit one or the other of these patterns to carry data. Welborn (Freescale)

10. One possible mapping of pulses to bits: Use 31-chip Codes • Can support both coherent and non-coherent pulse compression • Add 33 zero chips to get baseline mode for non-coherent receivers • However, these codes have poor spectral properties (see following slides) Welborn (Freescale)

11. Signal structure using a 31-chip Burst Sequence Hypothetical signal using 31-pulse sequence Can use coherent or non-coherent receiver Can use PPM/OOK by sending pulse burst in Either first or second bit location Ts = 140 ns Tm = ~290 ns Based on same 31-chip sequences proposed by Francois Chin of I2R at ~4.5 ns Tc spacing These codes need to be further analyzed to make sure spectral properties are acceptable Welborn (Freescale)

12. Code number 1 Back-off = -5.1601 dB Code number 2 Back-off = -4.7141 dB -40 -40 -50 -50 -60 -60 -70 -70 2 3 4 5 6 2 3 4 5 6 Code number 3 Back-off = -4.4672 dB Code number 4 Back-off = -5.9843 dB 9 9 x 10 x 10 -40 -40 -50 -50 -60 -60 -70 -70 2 3 4 5 6 2 3 4 5 6 Code number 5 Back-off = -5.2357 dB Code number 6 Back-off = -4.4672 dB 9 9 x 10 x 10 -40 -40 -50 -50 -60 -60 -70 -70 2 3 4 5 6 2 3 4 5 6 9 9 x 10 x 10 PSD plots for Proposed 31-chip codes – These codes cost 5 dB or more in Tx power Welborn (Freescale)

13. The Impact of a Poor Spectrum • As we see, the PSD using the 31-chip codes results in about 5 dB Tx power reduction • Result is reduced range and/or robustness • An alternative is to consider similar length codes that have better spectral properties • One example would be length-24 ternary codes with two “zeros” per code • Codes exist that could provide only a 2 dB penalty on Tx power (see next page) • Other codes exist, including “hierarchical codes”, analysis is ongoing Welborn (Freescale)

14. 24-bit Code number 1 Back-off = -1.9077 dB 24-bit Code number 2 Back-off = -1.9445 dB -40 -40 -50 -50 -60 -60 -70 -70 2 3 4 5 6 2 3 4 5 6 24-bit Code number 3 Back-off = -2.0199 dB 24-bit Code number 4 Back-off = -2.0419 dB 9 9 x 10 x 10 -40 -40 -50 -50 -60 -60 -70 -70 2 3 4 5 6 2 3 4 5 6 24-bit Code number 5 Back-off = -1.9027 dB 24-bit Code number 6 Back-off = -2.1993 dB 9 9 x 10 x 10 -40 -40 -50 -50 -60 -60 -70 -70 2 3 4 5 6 2 3 4 5 6 9 9 x 10 x 10 PSD plots for Proposed 24-chip codesMultiple codes are available with only ~2 dB backoff Welborn (Freescale)

15. PSD plots for Barker 11 & 13 codes (for reference) Barker-11 Back-off = -1.1789 dB Barker-13 Back-off = -2.8395 dB -35 -35 -40 -40 -45 -45 -50 -50 -55 -55 -60 -60 -65 -65 -70 -70 2 3 4 5 6 2 3 4 5 6 9 9 x 10 x 10 Welborn (Freescale)

16. Expanded View of 24-chip Burst Sequence Similar signal using 24-pulse sequence Can use coherent or non-coherent receiver Can use PPM/OOK by sending pulse burst in Either first or second bit location Ts = 109 ns Tm = ~218 ns One BPPM symbol 24-chip codes sent at 221 MHz rate (~4.5 ns per pulse) The “burst” rate is an average 2.3 MHz for the 2-PPM mode Welborn (Freescale)

17. Proposed System Parameters (Mandatory Center Band) • Bandwidth: Optional bands #1 & 3 are slightly different BW and frequency as noted on previous slides • Wide band #4 uses narrower pulses to achieve higher bandwidth Welborn (Freescale)

18. Proposal is to allow RFD to have only non-coherent receiver Will have reduced range, but much lower complexity RFD can do TOA ranging and will need FFD to do TDOA ranging FFD can form and coordinate piconet for low cost/low complexity RFD radios RFD and FFD Coherent Receiver= FFD RFD can use simple non-coherent receiver for OOK or PPM FFD Welborn (Freescale)

19. Ranging • Can support ranging for both coherent and non-coherent receivers • Coherent receivers act as “Full function devices” (FFD) and non-coherent receivers act as “Reduced function devices” (RFD) • RFDs can do TOA ranging at short distance in less severe channels (same room?) • RFDs can participate in a piconet with FFDs that can serve as “reference” nodes to do TDOA ranging Welborn (Freescale)

20. Positioning from TOA 3 anchors with known positions (at least) are required to retrieve a 2D-position from 3 TOAs Anchor 2 (xA2,yA2) Anchor 1 (xA1,yA1) Mobile (xm,ym) Anchor 3 (xA3,yA3) Estimated Position Measurements Specific Positioning Algorithms TOA Ranging for both FFD and RFD Welborn (Freescale)

21. TDOA Ranging Requires FFDs to Act as “Reference Nodes” reference node= FFD SOI = RFD – only needs to transmit signal when TDOA ranging FFD FFD Key: Sync Pulse Location Pulse TDOA backhaul • Controller: • Can be wired or wireless connection to FFDs • Needs protocol to allow synchronizing clocks Mode 2 - Active Welborn (Freescale)

22. Proposed Signal uses 24-chip pulse sequence, similar to original “Chaotic” noise signals and can support Non-coherent Receivers Original signal proposed by Samsung for non-coherent receiver Ts = 100 ns Tm = 400 ns Similar signal using 31-pulse sequence Can use coherent or non-coherent receiver Can use PPM/OOK by sending pulse burst in Either first or second bit location Ts = 109 ns Tm = ~218 ns Welborn (Freescale)