720 likes | 855 Views
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [TG3a-Wisair-CFP-Presentation] Date Submitted: [5 May, 2003] Source: [Gadi Shor] Company: [Wisair] Address: [24 Raoul Wallenberg st. Ramat Hachayal, Tel-Aviv, ISRAEL]
E N D
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [TG3a-Wisair-CFP-Presentation] Date Submitted: [5 May, 2003] Source: [Gadi Shor] Company: [Wisair] Address: [24 Raoul Wallenberg st. Ramat Hachayal, Tel-Aviv, ISRAEL] Voice: [+972-3-7676605] FAX: [+972-3-6477608], E-Mail: [gadi.shor@wisair.com] Re: [802.15.3a Call for proposal] Abstract: [Updated presentation for the P802.15.3a PHY standard] Purpose: [Response to WPAN-802.15.3a Call for Proposals] 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. Gadi Shor, Wisair
Proposal Update:UWB Multi-band Alternate Physical Layer for TG 802.15.3a Gadi Shor, Wisair
Proposal Contents • General Overview • Proposal Principles • Coding & Interleaving • Preamble & Acquisition • Band Management • Implementation Feasibility • Performance Results • Evaluation Matrix Gadi Shor, Wisair
General Overview Gadi Shor, Wisair
UWB Multi-Band Evolution • At the March IEEE meeting, many proposals contained common key elements: • High spectrum flexibility to meet changing regulatory and interference environments • Divide spectrum into a number of 'bins', on the order of 500-700 MHz • Serial transmission of bands for ease of implementation Gadi Shor, Wisair
Early collaboration between IEEE meetings for Best Technical Solution • Main ideas included were: • Time Frequency Interleaving Sequences (TFI) • Band plan • Straddled bands • Variable PRF • Preamble design • FEC • Operational modes Gadi Shor, Wisair
UWB Multi-Band Support • The following companies have indicated their support for this presentation : • General Atomics • Intel • Philips • Staccato Communications • Time Domain • Wisair • Further support, contributions and ideas are welcome Gadi Shor, Wisair
Future 802.15.3a Merge Work Wisair will be cooperating with: • General Atomics • Intel Corporation • Philips • Staccato Communications • Time Domain • Samsung • Appairent • Femto Devices • FOCUS Enhancements • Fujitsu • Infineon • Institute for Infocomm Research • Taiyo Yuden R&D of America • Objectives: • “Best” Technical Solution • ONE Solution • Excellent Business Terms • Fast Time To Market We encourage participation by any party who can help us reach our goals. Gadi Shor, Wisair
Proposal Overview • Available spectrum divided into sixteen, 538 MHz sub-bands • Typically, 7of the 8 lower sub-bands are used • Serial transmission of bands for ease of implementation • Multiple piconet isolation obtained through time-frequency codes, FEC, variable PRF, rake reception, and/or dynamic band selection • BPSK and QPSK modulation used in each sub-band • Convolutional coding with optional Reed-Solomon concatenated codes • Dynamic band management for interference mitigation and fading conditions Gadi Shor, Wisair
Proposal Principles Gadi Shor, Wisair
Unexpected Interferer Low Frequency Group Low Frequency Group Low Frequency Set Low Frequency Group High Frequency Group High Frequency Set High Frequency Group High Frequency Group 8 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7 9 9 9 9 10 10 10 10 11 11 11 11 12 12 12 12 13 13 13 13 14 14 14 14 15 15 15 15 Reserved Reserved Reserved ~ ~ ~ ~ ~ ~ 3.1 10.6 Drop band in Drop band in Sacrifice sub-band for coexistence and interference mitigation (based on regulation and geographical location) Drop band in Europe Drop band in Europe Japan Japan Flexible Spectrum Use • Center frequencies chosen for ease of implementation • 440 MHz band separation for improved flexibility • ~538 MHz wide bands to best utilize spectrum Gadi Shor, Wisair
Narrowband Interferer 8 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 9 9 10 10 11 11 12 12 13 13 14 14 15 15 Reserved Drop band in Drop band in Europe Bands 5 and 6 are both affected Japan ~ ~ Main Multi-band Set • Narrowband interferer between sub-bands affects both bands • - Can be avoided by using the straddled bands Gadi Shor, Wisair
Narrowband Interferer 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 9 9 10 10 11 11 12 12 13 13 14 14 15 15 0 0’ 1 1’ 2 2’ 3 3’ 4’ 4 5’ 5 6 6’ 7’ 7 9 9’ 10 10’ 11 11’ 12’ 12 13’ 13 14’ 14 8’ Reserved Reserved Reserved Drop band in Drop band in Drop band in Europe Only band 5’ is affected Drop band in Europe Japan Japan ~ ~ Straddled Multi-band • Enables flexibility for coexistence • Enhances worldwide regulation compliance • Used to best avoid particular narrowband interferers • Only one group is active at any time • Straddle group selection is “static” (i.e. upon radio start-up, or configured in factory based on global region of deployment/operation) Gadi Shor, Wisair
Band Plan • Two frequency groups: A & B • 220 MHz frequency shift between groups • 440 MHz separation between sub-bands • 538 MHz sub-band bandwidth Gadi Shor, Wisair
3.79 ns chip time Signal Design Rectified cosine envelope x Gadi Shor, Wisair
~ ~ ~ ~ Code duration 26.53 ns 3.79 ns chip time Length 7 Time-Frequency Code • Time-Frequency Multiple Access (TFMA) radio • Serial transmission of bands • Enables simplicity in receiver architecture • Provides low power solution Gadi Shor, Wisair
Time Frequency sequences Each piconet can use a different sequence The sequences has one collision property S 1 0 1 2 3 4 5 6 S 2 0 2 4 6 1 3 5 S 3 0 3 6 2 5 1 4 S 4 0 4 1 5 2 6 3 S 5 0 5 3 1 6 4 2 S 6 0 6 5 4 3 2 1 Gadi Shor, Wisair
Variable-Rate Multi-Band • Three pulse repetition intervals supported (26.5, 53, 79.5 nSec) to allow: • Reduced ADC sampling rate • Improved power consumption • Improved multiple access • Improved ISI immunity • Improved energy collection • Using off period • Can be done adaptively if conditions requires Gadi Shor, Wisair
Variable-rates Multi-Band • Pulse repetition interval per band: • 26.5 nSec: 7 pulses ~3.79 nSec with 264 Mpps • 53 nSec: 7 pulses ~3.79 nSec with 132 Mpps • 79.5 nSec: 7 pulses ~3.79 nSec with 88 Mpps • Reduce sampling rate for reduced bit rate Gadi Shor, Wisair
264 Mpps 1 3 5 7 2 4 6 1 3 5 7 2 4 6 1 3 5 7 2 4 6 1 3 5 7 2 4 6 1 3 5 7 2 4 6 1 3 5 7 2 4 6 132 Mpps 1 5 2 6 3 7 4 1 5 2 6 3 7 4 1 5 2 6 3 7 4 88 . Mpps 1 7 6 5 4 3 2 1 7 6 5 4 3 2 Variable-rate TFI sequences properties • Preserve time-frequency sequences collision properties for all modes • Reduce multi-path effect on collision between piconets • Improve multi-path mitigation • Enable energy collection 7 sub-bands using same frequency sequence in different PRF’s Gadi Shor, Wisair
Multiple Access Interference – High PRF Piconet isolation achieved through Time-Frequency sequences, coding and modulation properties Gadi Shor, Wisair
Multiple Access Interference – Lower PRF In severe cases, Piconet isolation is improved by reduced PRF Gadi Shor, Wisair
ISI immunity under severe multipath conditions In normal conditions multi-band does not suffer from ISI In severe multipath conditions ISI is solved by reducing the PRF Gadi Shor, Wisair
Better Energy Collection using single RF chain Receiver can collect energy (if conditions requires) in the "off" period using single RF chain Gadi Shor, Wisair
Coding & Interleaving Gadi Shor, Wisair
Coding & Interleaving Block Diagram Gadi Shor, Wisair
Error Correction Coding • Rate ½ Convolutional code, Constraint length =7, optionally punctured to rate ¾ • Optional Outer code: Reed Solomon RS(255,233) • Coded bits are spread across the sub-bands • Receiver can use optimal Metric per sub-band • Multi-band approach with per-band modulation enables optional use of different coding rates across different sub-bands Gadi Shor, Wisair
Convolutional Code Parameters Coding Parameters , Reed-Solomon Coding Parameters Gadi Shor, Wisair
Interleaving Scheme • Inner Interleaver: Ensures that the two coded bits generated from one data bit are assigned to two different sub-bands • One data bit is spread across multiple frequencies and time • Interleaver depth: 2* No. of used frequencies 7 band system - Interleaving Sequence R=1/2 , Cx , Cx+1 are generated from same data bit, x is even Gadi Shor, Wisair
Scrambler • Use same scrambler as 802.15.3 standard • PHY preamble and header are not scrambled Gadi Shor, Wisair
Operational Modes • Operational modes use 7 bands • Some bands may be omitted for fading or to reduce interference from other channels • Mode used for sending beacon and PHY headers, has same data on all frequencies • Beacon can be demodulated by devices with any number of sub-bands (e.g. 1,4,7,14) Gadi Shor, Wisair
Data Rate ( Mbps ) Chip Rate Convolutional Convolutional RS Concatenated ( MHz ) Modualtion No Coding R = 1 / 2 R = 3 / 4 ( 233 / 255 ) ( RS + CC 1 / 2 ) 264 7 Band BPSK 264 132 198 241 . 2 120 . 6 264 7 Band QPSK 528 264 396 482 . 4 241 . 2 132 7 Band BPSK 132 66 99 120 . 6 60 . 3 132 7 Band QPSK 264 132 198 241 . 2 120 . 6 88 7 Band BPSK 88 44 66 80 . 4 40 . 2 88 7 Band QPSK 176 88 132 160 . 8 80 . 4 264 14 Band QPSK 1056 528 792 964 . 9 482 . 4 Optional Data Rates Many possible modesto select from Gadi Shor, Wisair
Preamble & Acquisition Gadi Shor, Wisair
Rotated Barker4 Example Time-frequency sequence 0 5 3 1 6 4 2 0 5 3 1 6 4 2 0 5 3 1 6 4 2 0 5 3 1 6 4 2 + + + - + + + + + - + + + - + - + + + - + - + + + - + + Chips One acquisition symbol – each frequency cycles through Barker4 sequence Preamble structure • Both preambles implement rotated Barker sequences on top of TFMA coding to increase piconet isolation during acquisition • Initial Preamble uses the Barker4 sequence at half rate PRF • Continuous Preamble uses Barker4 at with smaller number of repetitions • Rotated Barker sequences applied on a per-band basis • Provides enhanced piconet isolation during acquisition • Provides enhanced resistance to multipath during acquisition Gadi Shor, Wisair
Gain Init. Signal Detection Coarse Optimize Fine Optimize Phase Determination Delimiter Detect 1.1 ms 5.5 ms 3.8 ms 1.7 ms 0.4 ms 0.2 ms Preamble Definition • Initial Preamble (Barker4 sequence always @ half rate PRF): • 59 repetitions of the Barker4 pattern at half rate PRF: 12.5 ms • A single inverted Barker4: 0.2 ms • 12.7 -ms total duration Example Timeline (Actual allocation is implementer's choice) • Continuous Preamble (Barker4 sequence example @ full PRF): • 39 repetitions of the Barker4 pattern: 4.1 ms • A single inverted Barker4: 0.1 ms • 4.2-ms total duration Example Timeline (Actual allocation is implementer's choice) Signal Detection Coarse Optimize Fine Optimize Phase Determination Delimiter Detect 1.5 ms 1.6 ms 0.8 ms 0.2 ms 0.1 ms Gadi Shor, Wisair
Acquisition Algorithm • Adjust gain to bring the signal into the linear range of A/D • Search time-frequency code space at ½-chip intervals • Optimize lock spot • Make initial phase determination for each band Gadi Shor, Wisair
Band Management Gadi Shor, Wisair
Enabling the spectral flexibility of Multi-Band over 802.15.3 MAC What do we accomplish? • Regulatory compliance with one global design • Environmental assessment at piconet inception • Interference avoidance by individual devices • Adapting to channel-induced fading • FDMA fallback to combat severe near/far situations in multiple access. Gadi Shor, Wisair
Regulatory compliance • Designation of allowed bands for regulatory compliance • Band selection for this purpose is a static function • Occurs during power-on initialization or at factory (depending on regulatory requirements of region for compliance testing) • Enables single silicon design for global deployment Gadi Shor, Wisair
Piconet Inception • DME layer polls MAC layer to determine useable bands out of set that is allowable • Useable bands determined by performing environment monitoring to assess activity in bands • This activity defines usable bands for piconet • Individual Devices are still permitted to do spectral adjustments dynamically, to drop bands from useable set • Allows Devices to tailor bands used based on near-proximity behavior of a device pair Gadi Shor, Wisair
Dynamic Adjustment within Active Piconet • Infrequent monitoring of environment • Two conditions to assess: • Narrowband interference • Severe channel-induced fading • Allows individual Devices or the piconet coordinator to eliminate a band from use • Devices coordinate to define bands that will be used for Device-Device communication Gadi Shor, Wisair
FDMA Fallback Mode • Enables excellent isolation to combat severe Simultaneously Operating Piconets (SOP) conditions: • severe near/far problems • adjacent piconets in extremely high multipath environments Gadi Shor, Wisair
Implementation Feasibility Gadi Shor, Wisair
Block Diagram – Analog Section Note: Power Consumption for 132 / 264 Mbps Gadi Shor, Wisair
MultiBand Generator • Many possible architectures • Can be implemented using either SiGe or CMOS process • Example with only one Oscillator • Low power consumption / Small die size Gadi Shor, Wisair
MultiBand Generator 132 Mpps 2mW 18mW DC 440 MHz Chip Rate Clk 1056 MHz 880 MHz MUX Sub-Band 5 : 1 5280 MHz 1320 MHz Generator 10mW 1760 MHz 12, 19.2, 20 MHz and others 9mW 5280 MHz MultiBand Generator Out SSB U/L • Power Consumption of 132 Mpps MultiBand Generator: 39 mW Gadi Shor, Wisair
Sub-Band Generator 1056 MHz :5 4 x Pulse Rate 1760 MHz 880 MHz 5280 MHz DC :3 :2 440 MHz 1.8GHz LPF :2 1.0GHz LPF 1320 MHz 12, 19.2, 20 MHz and more :2 :2 SSB MultiBand 5280 MHz Generator Out - Sub-Band Generator - Simple, low power consumption design - Based on mature radio technology Gadi Shor, Wisair
Single Sub-Band Spectrum Adjacent sub-band is ~23 dB down relative to main sub-band Gadi Shor, Wisair
MultiBand Generator 264 Mpps(Back to Back Pulses) 3mW 18mW DC 440 MHz Chip Rate Clk 1056 MHz 880 MHz Sub-Band MUX Generator 5 : 2 5280 MHz 1320 MHz 10mW 1760 MHz 9mW 12, 19.2, 20 MHz and more 5280 MHz SSB U/L MultiBand Generator Out 9mW SSB U/L • Power Consumption of 264 Mpps MultiBand Generator: 49 mW Gadi Shor, Wisair
264 Mpps MultiBand Signal Switching is done when pulses amplitude is close to zero Realistic switching time has negligibleeffect on pulse shape Gadi Shor, Wisair