January 2005 doc IEEE 802 15 05 0013

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Time-Domain-CFP-Response] Date Submitted: [4 January, 2005] Source: [Vern Brethour, Adrian Jennings] Company: [Time Domain Corp. ] Address: [7057 Old Madison Pike; Suite 250; Huntsville, Alabama 35806] Voice: [Vern: (256) 428 -6331; Adrian: (256) 428 -6326], E-Mail: [vern. brethour@timedomain. com; adrian. jennings@timedomain. com] Re: [802. 15. 4 a CFP] Abstract: [802. 15. 4 a CFP response from Time Domain. An impulse radio nominally occupying 3 – 5 GHz with 4 ns chip times using 40 chips/symbol and 300 ns quiet time between symbols. ] Purpose: [Response to WPAN-802. 15. 4 a CFP] Notice: This document has been prepared to assist the IEEE P 802. 15. It is offered as a basis for discussion and is not binding on the contributing individuals or organization. The material in this document is subject to change in form and content after further study. The contributors reserve the right to add, amend or withdraw material contained herein. Release: The contributors acknowledge and accept that this contribution becomes the property of IEEE and may be made publicly available by P 802. 15. Submission 1 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Time Domain Proposal: Single Band UWB Alternate Physical Layer for TG 802. 15. 4 a Submission 2 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Proposal Contents • • • General Overview Proposal Principles Regulatory Flexibility Performance Evaluation Matrix (in backup slides) Submission 3 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a General Overview • • Impulse radio Single band nominally from 3 to 5 Ghz. 4 ns chip times 40 chips per symbol 300 ns quiet time between symbols Max symbol integration = 64 (data) Max symbol integration = 256 (acquisition) Submission 4 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Proposal Principles • The most important part of a proposal is the signal as it appears on the air. For most signal definitions, there are many ways to build a radio, and as many corresponding performance results. However, as a standard, we can define a signal which will forever limit the systems ultimate performance. (For example, by not using all reasonably available bandwidth. ) Submission 5 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a The need for robust links • There is already a 15. 4 a radio at 2. 54 GHz. We must be substantially better than that radio. • This proposal provides the opportunity for maximum performance by occupying as much bandwidth as reasonable. Submission 6 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Regulatory Flexibility • There are fundamentally two approaches to UWB regulatory flexibility: – 1) using multiple bands. – 2) longer chip times. • Using long chip times allows for filters if needed and does little harm if not needed. Submission 7 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Regulatory Flexibility • This proposal occupies all of the spectrum between the ISM bands and the UNII bands • This proposal allows ample (4 ns) chip time to accommodate spectral shaping if necessary. • This proposal also allows a future (optional) band between 6 and 10 GHz. Submission 8 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Support for positioning • There already radios which do the low data rate communications job without positioning. • Excellent positioning performance will be the key differentiator for 15. 4 a. • Use of as much bandwidth as reasonable gives the best positioning performance. Submission 9 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a What about the “simple radio” approach? • Vocabulary is important here. Words like “simplicity” imply virtue. Words like “crude” and “unsophisticated” might be used by others to describe the same radio. • The critical issue is that there will be other users of the spectrum and the 4 a standard must use spectrum and air time efficiently and effectively. • A proposed standard which we think implies a “simple and virtuous” radio might be viewed by others as spectrally wasteful and unworthy of letter ballot approval. Submission 10 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a What does “simple radio” mean? • A “simple radio” to our customers doing system integration, is a radio with the lowest chip count, the least number of passives and the most forgiving antenna driver. • The integration customer does not (and should not) care how hard we have to work to implement the design inside of our chip. Submission 11 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Performance: the optimistic story. • A “marketing style” link budget looks very optimistic. Even for 250 KByte/sec links, at 100 meters the link budget shows over 6 d. B of margin. Submission Parameter Value Information Data Rate 1 Kbps 250 Kbps Average TX Power -12 d. Bm Total Path Loss 84. 5 d. B (@ 100 meters) Average RX Power -96. 5 d. Bm Noise Power Per Bit -144 d. Bm -120 d. Bm CMOS RX Noise Figure 8 d. B Total Noise Power -136 d. Bm -112 d. Bm Required Eb/N 0 2. 25 d. B Implementation Loss 6 d. B Link Margin 31. 25 d. B 7. 25 d. B RX Sensitivity Level -128 d. Bm -104. d. Bm Max. Range (AWGN) 3652 m 230 m 12 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Link Performance: A realistic story. • Performance predicted by the link budget is optimistic primarily due to the use of “ 2” for the path loss exponent. • Links inside buildings with interior walls, will suffer path loss exponents more like “ 3”. Submission 13 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Link Performance • A more realistic idea of performance is available by scaling the results of the simulations done for 802. 15. 3 a to longer ranges and lower data rates. • The 802. 15. 3 a DS proposal uses signaling similar to this proposal, so I will scale from simulations reported in 802. 15. 0483 r 5 (Mc. Laughlin, November 2004). Submission 14 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Scaling the DS results: • The 3 a DS radio is simulating an 11. 8 meter link in CM 4 at 110 Mbit/sec with a 90% packet success rate. • Going from a link distance of 11. 8 meters to 100 meters would seem to require less than 20 d. B of additional processing gain. BUT that’s with a path loss exponent of 2. • A path loss exponent of 3 requires 28 d. B of processing gain. Submission 15 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a How much integration is needed for 28 d. B of processing gain? • Each time we double the integration, we get another 3 d. B of processing gain. • For 28 d. B, we need to do 10 doublings, or an integration rate of 1024. • Integration rate 1024 will take the 110 Mbit/sec rate down to 107 Kbit/sec. Submission 16 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Noticeable difference: Data rate Predicted range Link Budget with Path Loss exponent 2 250 Kbit/sec 245 meters Scaled Simulation with Path Loss exponent 3 107 Kbit/sec 118 meters Submission 17 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Even the Scaled Simulation is a very optimistic result: • The DS radio that this prediction rests on is a very fancy radio: – 16 Rake taps – 31 tap decision feedback equalizer – Constraint length 6 convolutional code with Viturbi decoder – RF front end with 6. 6 d. B noise figure Submission 18 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Link budgets do not address acquisition. • Acquisition will usually be the performance limiter at long range. • The Acquisition decision needs an additional 6 d. B of processing gain over data demodulation. Submission 19 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a We must acquire without benefit of a trained equalizer. • Equalizers are fine, but only after they have been trained. • If the spacing between symbols is too short, the resulting inter symbol interference makes trouble for acquisition. • This proposal uses a relatively long (300 ns) distance between symbols to handle large channel delay spreads without an equalizer. Submission 20 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Applications need robust links. • The applications can stand low data rates, so this proposal uses data symbol integration of 64 and acquisition symbol integration 256. • The long acquisition integration puts a burden on crystal tolerance (2 ppm) that not all vendors will want to deal with, so shorter integration modes will also be supported. Submission 21 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Clear Channel Assessment • This is a hard problem for all UWB approaches. • We should not ignore it. • Detection of energy at the chipping rate (as in the 15. 3 a DS proposal) is doable, but not reliable. • We may need relief from the MAC. Submission 22 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Simultaneously Operating Piconets • The long symbol (40 chips) enables good orthagonality between piocnets. • Different piconets use slightly different chipping rates like the 15. 3 a DS proposal. • Bits are modulated onto symbols using only BPSK so all of the symbol orthogonality is used for piconet isolation. Submission 23 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Power control is the key to compatibility with 15. 3 a • This proposal is set up for 100 meter links. • Many applications will have shorter links. • For shorter links, we turn down the Tx power. • Power control gives superior compatibility with all services. Submission 24 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Proposal Summary • • Impulse radio Single band nominally from 3 to 5 Ghz. 4 ns chip times 40 chips per symbol 300 ns quiet time between symbols Max symbol integration = 64 (data) Max symbol integration = 256 (acquisition) Submission 25 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Backup Slides Submission 26 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Evaluation Matrix Submission 27 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Self Evaluation – General Solution Criteria CRITERIA Evaluation Unit Manufacturing Cost (UMC) +(no need for an equalizer) Signal Robustness Interference +(due to power control) Signal Robustness Susceptibility +(due to using max bandwidth) Coexistence +(due to power control) Manufacturability +(due to low peak Tx amplitudes) Time To Market + Regulatory Impact + (due to long chip times) Technical Feasibility Scalability + Location Awareness +(due to using max bandwidth) Submission 28 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Self Evaluation – PHY Protocol Criteria Submission CRITERIA Evaluation Size and Form Factor + Payload Bit Rate + Packet Overhead + PHY-SAP Throughput + Simultaneously Operation Piconets +(due to the long 40 chip symbol) Signal Acquisition +(due to long symbol integration) System Performance + Link Budget +(due to using max bandwidth) Sensitivity + Power Management Modes + Power Consumption + Antenna Practicality + 29 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Example of a chip waveform Submission 30 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Multiple chips make a symbol: 1 2 3 4 5 6 7 8 38 39 40 …………… Non-inverted pulses are blue, Nulled pulses are orange, Inverted pulses are green. ……………. . . 160 ns Submission Quiet time 31 Vern Brethour, Adrian Jennings (Time Domain)

January 2005 doc. : IEEE 802. 15 -05 -0013 -01 -004 a Allow plenty quiet time between symbols ………………………. 160 ns Submission 300 ns 32 Vern Brethour, Adrian Jennings (Time Domain)