Post on 29-Dec-2015
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 1
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: STM_CEA-LETI_CWC_AETHERWIRE 15.4aCFP responseDate Submitted: January 4th, 2005Source: Ian Oppermann (1), Mark Jamtgaard (2), Laurent Ouvry (3), Philippe Rouzet (4)Companies:
(1) CWC-University of Oulu, Tutkijantie 2 E, 90570 Oulu, FINLAND (2) Æther Wire & Location, Inc., 520 E. Weddell Drive, Suite 5, Sunnyvale, CA 94089, USA (3) CEA-LETI, 17 rue des Martyrs 38054, Grenoble Cedex, FRANCE (4) STMicroelectronics, CH-1228, Geneva, Plan-les-Ouates, SWITZERLAND
Voice: (1) +358 407 076 344, (2) 408 400 0785 (3) +33 4 38 78 93 88, (4) +41 22 929 58 66 E-Mail: (1) ian@ee.oulu.fi, (2) mark@aetherwire.com(3) laurent.ouvry@cea.fr, (4) philippe.rouzet@st.com,
Abstract: UWB proposal for 802.15.4a alt-PHY
Purpose: Proposal based on UWB impulse radio for the IEEE 802.15.4a CFP
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 contributors acknowledge and accept that this contribution becomes the property of IEEE and may be made publicly available by P802.15
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 2
List of Authors
• CWC – Ian Oppermann, Alberto Rabbachin (1)
• AetherWire – Mark Jamtgaard, Patrick Houghton (2)
• CEA-LETI – Laurent Ouvry, Samuel Dubouloz, Sébastien de Rivaz, Benoit Denis, Michael Pelissier, Manuel Pezzin et al. (3)
• STMicroelectronics – Gian Mario Maggio, Chiara Cattaneo, Philippe Rouzet & al. (4)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 3
Outline• Introduction
• Transmitter
• Receiver architectures
• System performances
• Link budget
• Framing, throughput
• Power Saving
• Ranging
• Proof of concept
• Conclusions
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 4
Introduction (1/2)
• Proposal main features:1. Impulse-radio based (pulse-shape
independent)2. Support for different receiver architectures
(coherent/non-coherent)3. Flexible modulation format4. Support for multiple rates5. Enables accurate ranging/positioning6. Support for multiple SOP
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 5
Introduction (2/2)• Motivation for (2-4):
• Supports homogenous and heterogeneous network architectures
• Different classes of nodes, with different reliability requirements (and cost) must inter-work
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 6
Commonalities with Other Proposals
• Many commonalities exist between the CWC/Aetherwire/LETI/STM proposal and other proposals, including FT and Mitsubishi:
– UWB technology– Modulation features– Bandwidth usage– Ranging approach
• Discussions are under way for future collaborations and merging
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 7
UWB Technology
• Impulse-Radio (IR) based:– Very short pulses Reduced ISI– Robustness against fading– Episodic transmission (for LDR) allowing
long sleep-mode periods and energy saving
• Low-complexity implementation
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 8
Modulation Features
• Simple, scalable modulation format
• Flexibility for system designer
• Modulation compatible with multiple coherent/non-coherent receiver schemes
• Time hopping (TH) to achieve multiple access
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 9
Bandwidth Usage (1/2)
• Flexible use of (multi-)bands depending on application and regulatory environment
• Use of TH and/or polarity randomization for spectral smoothing
• Noise-like interference towards existing radio services
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 10
Bandwidth Usage (2/2)
0.96 3.1 5.1 6.0 8.0 8.1 10.1 GHz
ISM Band
Upper Band 1
Upper Band 2
Upper Band 3Lower band
ISM Band
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 11
Ranging Approach
• Signal bandwidth ≥ 1GHz for very good location accuracy
• Two-way ranging protocol to avoid synchronization between nodes
• Location based on ranging from several nodes on a higher layer
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 12
Preliminaries (1/2)
• Definitions:– Coherent RX: The phase of the received carrier
waveform is known, and utilized for demodulation– Differentially-coherent RX: The carrier phase of
the previous signaling interval is used as phase reference for demodulation
– Non-coherent RX: The phase information (e.g. pulse polarity) is unknown at the receiver -operates as an energy collector
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 13
Preliminaries (2/2)
• Pros (+) and cons (-) of RX architectures:– Coherent
• + : Sensitivity• + : Use of polarity to carry data• + : Optimal processing gain achievable• - : Complexity of channel estimation and RAKE receiver• - : Longer acquisition time
– Differential (or using Transmitted Reference)• + : Gives a reference for faster channel estimation (coherent approach)• + : No channel estimation (non-coherent approach)• - : Asymptotic loss of 3dB for transmitted reference (not for DPSK)
– Non-coherent• + : Low complexity• + : Acquisition speed• - : Sensitivity, robustness to SOP and interferers
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 14
½ PRP ½ PRP
« 1 »
« 0 » TR-BPSK
D
« 1 »
« 0 » DBPSK (one pulse per PRP )
« 1 »
« 0 » BPPM
TX: Modulation Formats« 1 »
« 0 »OOK
PRP
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 15
½ PRP ½ PRP
« 1 »
« 0 » TR-BPSK
D
« 1 »
« 0 » DBPSK
« 1 »
« 0 » BPPM
TX: Multi-pulse Modulation Formats« 1 »
« 0 »OOK
Scope for Adding more information with multi-pulse
PRP
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 16
Transmitted Reference (TR)
• TR schemes simplify the channel estimation process• Reference waveform available for synchronisation• Potentially more robust (than non-coherent) under SOP
operation• Supports both coherent/differentially-coherent demodulation• Reference waveform averaging (non-coherent integration);
– see also GLRT [Franz, Mitra; Globecom’03, pp. 744-748, Dec 2003]
• Implementation challenges:– Analogue: Implementing delay value, – delay mismatch, jitter
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 17
TR Schemes (1/3)• GTR (Generalized Transmitted Reference) BPSK
• Concept: Multi-level version of the TR scheme, where the energy associated with the reference pulse is “shared” to improve efficiency
« A »
« B »
« C »
« D »
D D
PRP
Extension to N-ary TR
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 18
TR Schemes (2/3)
• TR-BPPM (with/without BPAM)
• Concept: Transmitted-reference version of BPPM, with BPAM [Zasowski, Althaus and Wittneben, Proc. IWUWBS/UWBST’04, Kyoto, Japan]• TR-BPPM (non-coherent): Binary symbols restricted to “A” and “B”
D1
D2
« A »
« B »
« C »
« D »
PRP
Extension to N-ary TR
CoherentDetection
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 19
TR Schemes (3/3)
• TR-PCTH (pseudo-chaotic time hopping) [Maggio, Reggiani, Rulkov; IEEE Trans. CAS-I, v. 48, no. 12, p. 1424, Dec 2001]
• Concept: Random TH Smoothes spectral lines in the PSD • Modulation: Pulses in the first ½ PRP correspond to “0” and vice versa for “1”• Demodulation: Similar to PPM, but more flexible (threshold or Viterbi detector)
½ PRP ½ PRP
« 0 »
« 1 »
Random inter-pulse interval Extension to N-ary TR
D
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 20
Transmission
• Combine BPPM with more sophisticated TR scheme– Non-coherent receiver sees BPPM with pulse stream per bit– More sophisticated receiver sees BPPM (1 bit) plus bits
carried in more sophisticated modulation scheme (e.g. extended TR)
• Advantages: – Differential and non-coherent receiver may coexist– reference can be used for synch and threshold estimation
• Concept can be generalized to N-ary TR-BPSK
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 21
Design Parameters (1/6) • Motivation:
– Flexible waveform – Still simple– Compatible with multiple coherent/non-coherent receiver schemes
• Limitations (compliant with FCC)– Increased Bandwidth (pros/cons)
• (+) High transmit power• (+) High time resolution• (-) Increased design complexity• (-) Less stringent requirements on out of band interference filtering Signal BW of 500 MHz - 2 GHz in Upper bands
Signal BW of 700 MHz in 0 to 960 MHz Lower band (low band)
– Increased Pulse Repetition Period (pros/cons)• (+) more energy per pulse (easier to detect single pulse)• (+) Lower inter-channel interference due to channel delay spread• (-) Transmitter peak voltage compatible with technology• (-) Acquisition time PRP (chip period) Between 250ns and 500ns
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 22
• Simple modulation schemes:• BPPM combined with Transmitted Reference min 1 bit/symbol for non-coherent, 2 bits/symbol for TR (more for GTR)
• Channelization :• Coherent schemes: Use of TH codes and polarity codes• Non-coherent schemes: Use of TH codes (polarity codes for spectrum smoothing
only)
• Increased TH code length (pros/cons):• (+) higher processing gain, robustness to SOP operation• (-) Lower bit-rate• (-) Faster acquisition, shorter frame size (synch. phase) TH code length 8 or 16
TX: Design Parameters (2/6)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 23
•Basic Mode - Upper-bands (XH0=250 Kbps):– PRP = 250 ns, binary modulation, TH code length of 16chips
– N pulses per symbol (1 < N < 124)
– PHY-SAP payload bit rate (Xo) is 250 kbps
•Enhanced Mode 1 - Upper-bands (XH1=500 Kbps):– PRP = 250 ns, 4-level modulation, TH code length of 16chips
– N pulses per symbol (1 < N < 124)
– PHY-SAP payload bit rate (Xo) is 500 kbps
•Enhanced Mode 2 - Upper-bands (XH2=1000 Kbps):– PRP = 250 ns, 8-level modulation, TH code length of 16chips
– N pulses per symbol (1 < N < 40)
– PHY-SAP payload bit rate (Xo) is 1000 kbps
TX: Design Parameters (3/6)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 24
TX: Design Parameters (4/6)« 1 »
« 0 »Basic Mode
D
« 1 1 »
« 1 0 »
Enhanced Mode 1«0 1 »
«0 0 »
« 1 0 1 0 »
½ PRP ½ PRP
« 1 1 1 1»
Enhanced Mode 2
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 25
« 1 0 » Enhanced Mode 1
TX: Design Parameters (5/6)
TH Pattern
« 1 1 »
Basic Mode(as seen by receiver)
« 1 »
Need not fill entire slot
TH Code 1,1 1,1 0,1 0,0 1,0 0,1Data 1,1 1,1 1,1 1,1 1,1 1,1
Position Swap, polarity invert
« 1 1 »Enhanced Mode 1 (randomising code)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 26
•Basic Mode - Lower-band (XL0=250 Kbps):– PRP = 500 ns, binary modulation, TH code length of 8 chips
– N pulses per symbol (1 < N < 120)
– PHY-SAP payload bit rate (Xo) is 250 kbps
•Enhanced Mode 1 - Lower-band (XL1=500 Kbps):– PRP = 500 ns, 4-level modulation, TH code length of 8 chips
– N pulses per symbol (1 < N < 120)
– PHY-SAP payload bit rate (Xo) is 500 kbps
•Enhanced Mode 2 - Lower-band (XL2=1000 Kbps):– PRP = 500 ns, 8-level modulation, TH code length of 8 chips
– N pulses per symbol (1 < N < 40)
– PHY-SAP payload bit rate (Xo) is 1000 kbps
TX: Design Parameters (6/6)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 27
Coherent Receiver Architecture
LNALNALNALNA BPFBPF ADCADC BufferBuffer
Band MatchedBand Matched
Estimated CIR
Estimated CIR
Integration / Decision
Integration / Decision
SynchronizationSynchronizationClock TrackingClock Tracking
Thresholds settingThresholds settingChannel EstimationChannel Estimation
SynchronizationSynchronizationClock TrackingClock Tracking
Thresholds settingThresholds settingChannel EstimationChannel Estimation
Coefficients
Trig
Threshold
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 28
Band MatchedBand Matched
LNALNALNALNA BPFBPF
SynchroSynchroTrackingTracking
ThresholdThresholds settings setting
SynchroSynchroTrackingTracking
ThresholdThresholds settings setting
DumpDumpLatchLatchDumpDumpLatchLatch
RA
ZR
AZ
DUMPDUMP
ControlledControlledIntegratorIntegrator
ADCADC
BPPM Demodulation BPPM Demodulation branchbranch
RAZRAZ
TriggerTrigger
Time baseTime baseTime baseTime base
THRESHOLDTHRESHOLD
ADCADC
ComparatorComparatorComparatorComparator
IntegratorIntegrator
Ranging Ranging branchbranch
Differentially-Coherent/Non-Coherent Receiver Architecture Basic Mode and Enhanced Mode 1
x2 x2r(t)
Recyle this branch for Enhanced Mode 2
DelayDelayDelayDelay
TR Demodulation TR Demodulation
branchbranch
DumpDumpLatchLatchDumpDumpLatchLatchADCADC
ControlledControlledIntegratorIntegrator BPPM BPPM
Synch Synch TriggerTrigger
TRTR
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 29
Band MatchedBand Matched
LNALNALNALNA BPFBPF
De-spreading TH Codes
r(t) TH Sequence Matched
Filter
Bit Demodulation Bit Demodulation
Band MatchedBand Matched
LNALNALNALNA BPFBPFr(t) TH
Sequence Matched Filter
Bit Demodulation Bit Demodulation
Case I - Coherent TH despreading
ADCADC
ADCADCb(t)
soft info
Case II – Non-coherent / differential TH despreading
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 30
PER in 15.4a Channel Model Non-Coherent (Energy Collection) BPPM
Framing format:
PreamblePreamble(32 bits)(32 bits)
SFDSFD(8 bits)(8 bits)
LENLEN(8 bits)(8 bits)
MHR+MSDUMHR+MSDU(240 bits)(240 bits)
CRCCRC(16 bits)(16 bits)
• Simulations over 1000 channel responses • BW = 2GHz – Integration Time = 80ns• Implementation loss + Noise figure margin : 11 dB• Max range is determined from:
Required Eb/N0, Implementation margin Path loss characteristics
X1 (CM8) X2 (CM1) X3 (CM5) X4 (CM9)
Required Eb/N0 19.5 dB 20 dB 21 dB 21.5 dB
Max Range (I) 10.78 m 84.61 m 86.72 m 58.67 m
Max Range (II) 7.33 m 53.25 m 54.15 m 34.72 m
16 17 18 19 20 21 22
10-2
10-1
100
2PPM - PER vs. Eb / N
0 - 15.4a Channel Models
Eb / N
0 [dB]
Pac
ket
Err
or R
ate
X1-CM8: industrial NLOSX2-CM1: Residential LOSX3-CM5: Outdoor LOSX4-CM9: Agricultural Areas
Case I: 250 kbps – PRP 250 ns with 16 pre-integrations = 4 µs
Case II: 250 kbps – PRP 500 ns with 8 post-integrations
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 31
PER/BER in 15.4a Channel Model DBPSK (RAKE)
10 11 12 13 14 15 16 17 18 19 2010
-3
10-2
10-1
100
PE
R
X1X2X3X4
Eb/N0 (dB)
DBPSK – PER vs. Eb/N0 – 15.4a Channel Models
X1 (CM8) X2 (CM1) X3 (CM5) X4 (CM9)
Required Eb/N0 18 dB 17.5 dB 18.5 dB 18.5 dB
Max Range (I) 12.66 m 116.70 m 120.27 m 90.84 m
Max Range (II) 9.18 m 79.34 m 81.23 m 58.67 m
Implementation loss and Noise figure margin : 11 dB
Theoretical BER Curves – Integration Time = 50 ns
0 5 10 1510
-5
10-4
10-3
10-2
10-1
Eb/N0 (dB)
BE
R
BER vs Eb/N0 for binary modulations - 100 equivalent uncorrelated samples
ideal MRC BPAM solutionDifferentially coherent BPAM
Case I: 250 kbps – PRP 250 ns with 16 pre-integration = 4 µs
Case II: 250 kbps – PRP 500 ns with 8 post-integrations
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 32
Link Budget: Non-Coherent (Energy Collection) BPPM
ParameterMandatory Value
(PRP = 4 µs) Optional Value
(PRP = 500ns - 8 integrations)
Peak Payload bit rate (Rb) 250 kb/s 250 kb/s
Average Tx Power Gain (PT) -10.64 dBm -10.64 dBm
Tx antenna gain (GT) 0 dBi 0 dBi
f’c: (geometric frequency) 3.873 GHz 3.873 GHz
Path Loss @ 1m: L1 = 20log10(4..f’c / c) 44.20 dB 44.20 dB
Path Loss @ d m: L2 = 20log10(d) 29.54 dB @ d = 30 m 29.54 dB @ d = 30 m
Rx Antenna Gain (GR) 0 dBi 0 dBi
Rx Power (PR = PT + GT + GR – L1 – L2) -84.38 dBm -84.38 dBm
Average noise power per bit: N = -174 + 10log10(Rb) -120.02 dBm -120.02 dBm
Rx noise figure (NF) 7 dB 7 dB
Average noise power per bit (PN = N + NF) -113.02 dBm -113.02 dBm
Minimum Eb/N0 (S) 14 dB 17.6 dB
Implementation Loss (I) 5 dB 5 dB
Link Margin (M = PR - PN – S – I) 9.64 dB 6.04 dB
Proposed Min. Rx Sensitivity Level -94.02 dBm -90.42 dBm
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 33
Link Budget: DBPSK (RAKE)
ParameterMandatory Value
(PRP = 4 µs)Optional Value
(PRP = 500ns - 8 integrations)
Peak Payload bit rate (Rb) 250 kb/s 250 kb/s
Average Tx Power Gain (PT) -10.64 dBm -10.64 dBm
Tx antenna gain (GT) 0 dBi 0 dBi
f’c: (geometric frequency) 3.873 GHz 3.873 GHz
Path Loss @ 1m: L1 = 20log10(4..f’c / c) 44.20 dB 44.20 dB
Path Loss @ d m: L2 = 20log10(d) 29.54 dB @ d = 30 m 29.54 dB @ d = 30 m
Rx Antenna Gain (GR) 0 dBi 0 dBi
Rx Power (PR = PT + GT + GR – L1 – L2) -84.38 dBm -84.38 dBm
Average noise power per bit: N = -174 + 10log10(Rb) -120.02 dBm -120.02 dBm
Rx noise figure (NF) 7 dB 7 dB
Average noise power per bit (PN = N + NF) -113.02 dBm -113.02 dBm
Minimum Eb/N0 (S) 13 dB 16 dB
Implementation Loss (I) 5 dB 5 dB
Link Margin (M = PR - PN – S – I) 10.64 dB 7.64 dB
Proposed Min. Rx Sensitivity Level -95.02 dBm -92.02 dBm
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 34
Framing – 802.15.4 Compatible
CAP CFP IPBP
Beacon Interval
BP : Beacon Period
CAP : Contention Access Period
CFP : Contention Free Period
IP : Inactive Period (optional)
Superframe Duration
Beacon slot CAP slot CFP slot
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Preamble SFD PSDU = MPDUPHY layer
PPDU (PHY Protocol Data Unit)
PSDU (PHY Service Data Unit)SHR
Octets 324 1
Frame length
PHR
1
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CWC/AETHERWIRE/CEA-LETI/STM
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Slide 35
Throughput
Preamble SFD PSDU = MPDUPHY layer
PPDU (PHY Protocol Data Unit)
PSDU (PHY Service Data Unit)SHR
Bytes 324 1
Frame length
PHR
1
Preamble SFD PSDUPHY layer
PPDU (PHY Protocol Data Unit)
PSDUSHR
Bytes 54 1
Frame length
PHR
1
Data Frame (32 octet PSDU) ACK Frame (5 octet PSDU)
Tdata TackT_ACK
• Numerical example (high-band)
• Preamble + SFD + PHR = 6 octets
• Tdata = 1.216 ms
• T_ACK = 50 s (turn around time requested by IEEE 802.15.4 is 192s)
• Tack = 0.352 ms
• IFS = 100μs
Throughput = 32 octets/1.718 ms = 149 kb/s Average data-rate at receiver PHY-SAP 250 kb/s (Basic Mode)
IFS
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CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 36
Saving Power• Power Saving techniques achieved by combining advantages offered at 3 levels:
– Technology (best if CMOS)
– Architecture (flexible schemes provided by the TH+pulse modulation)
– System level (framing, protocol usage)
• Selected techniques used in one existing realization (see proof of concept slides) – Low-duty cycle Episodic transmission/reception
• Scheduled wake-up
• 80s RTOS tick
– Ad-hoc networking using multi-hop• Special rapid acquisition codes / algorithm
• Matchmaking further reduces acquisition time
– Multi-stage time-of-day clock• Synchronous counter / current mode logic for highest speed stages
• Ripple counter / static CMOS for lowest speed stages
– Compute-intensive correlation done in hardware
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 37
Ranging
• Motivation :– Benefit from high time resolution (thanks to signal bandwidth):
• Theoretically: 2GHz provides less than 20cm resolution
• Practically: Impairments, low cost/complexity devices should support ~50cm accuracy with simple detection strategies (better with high resolution techniques)
• Approach :– Use Two Way Ranging between 2 devices with no network
constraint (preferred); no need for time synchronization among nodes
– Use One Way Ranging and TDOA under some network constraints (if supported)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 38
Two Way Ranging (TWR)
Terminal B
Request
Prescribed Protocol
Delay and/or Processing
Time
To
TReply
T1
Terminal A TX/RX
Terminal B RX/TX
TOF TOF
cTd
TTTT
AOFAB
AOF
.~~2
1~Reply01
TOF EstimationTerminal A
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 39
Two Way Ranging (TWR)
B
BAAAOFAOF f
fTfTT
12
1~ Reply
Main Limitations / Impact of Clock Drift on Perceived Time
Range estimation is affected by :
• Relative clock drift between A and B
• Prescribed response delay
• Clock accuracy in A and B
• Channel response (weak direct path)
Is the frequency offset relative to the nominal ideal frequency 0f0. f
Relaxing constraints on clock accuracy is possible by
• Performing fine drift estimation/compensation
• Benefiting from cooperative transactions (estimated clock ratios …)
• Adjusting protocol durations (time stamp…)
f/f \ Treply (max error)
192 s 10 s
4 ppm 0.23 m 0.01 m
40 ppm 2.30 m 0.12 m
Example using Imm-ACK SIFS of 15.4 and 15.3
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 40
20dB SNR, 3ns Integration Non-Coherent Energy Detection
TOA estimation with serial search. Parameters: uncertainty region of 13 ns, search region 20 ns, integration window 3 ns, SNR of 20 dB, CM1 (802.15.3a)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 41
TOA Error CDF (CM1 802.15.3a)
TOA error CDF for serial search. Integration window of 3 and 4 ns.
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 42
Antenna Feasibility Capacitive Dipole and Various Bowtie Antennas
Bowtie antenna
55 mm
40 mm
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 43
“Proof-of-Concept” (1) Non-coherent Transceiver
5 Mbps BPPM 350 ps pulse train
with long scrambling code
UWBANTENNA
DLLCM
Oscilator Generator
x16528 MHz
Flagrst8....
Flagrst1
RX
Controlline
Energycollection
DIGITALCONTROL
LOGIC
DLLPG
-DIGITALLOGIC UWB
PG
TX
Fref33 MHz
BASEBANDDSP
(decision logic)
DETECTIONBIT
DECISION
(digital)
2
( )
LNAVGA
GAIN SELECTION
A/DConverter
SWITCH
/2
Non-coherent, Energy Collection Receiver
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 44
“Proof-of-Concept” (2) Non-coherent Transceiver
UWB Transmitter400 μm x 400 μm
0.35 μm CMOS
UWB TransceiverTest architecture <10 mm2
0.35 μm SiGe Bi-CMOS
UWB-IR BPPM Non-Coherent Transceiver Implementation
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 45
“Proof-of-Concept” (3): Transmitter - Lower Band
UWB Transmitter chip for generating impulse doublets
Del
ayD
elay
Buf
fers
Buf
fers
N-CN-Channel DriversN-Channel Drivers
P-Channel DriversP-Channel Drivers
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 46
“Proof-of-Concept” (4): Receiver - Lower Band
Coherent UWB Receiver withmultiple time integrating correlators
32
Tim
e-I
nte
gra
ting
32
Tim
e-I
nte
gra
ting
Co
rre
lato
rsC
orr
ela
tors
PL
L L
oo
p F
ilte
rP
LL
Lo
op
Filt
er
VG
C A
mp
VG
C A
mp
CodeCodeSequenceSequenceGeneratorsGenerators
LF RTCLF RTC
DA
Cs
DA
Cs
““ Ra
ils”
for
test
ing
R
ails
” fo
r te
stin
g
an
alo
g c
ircu
itsa
na
log
cir
cuitsDA
Cs
DA
Cs
Hig
h-F
requ
ency
Hig
h-F
requ
ency
Rea
l Tim
e C
lock
Rea
l Tim
e C
lock
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 47
“Proof-of-Concept” (5) High Speed Coherent Circuit Elements
3-5 GHz LNAChip and layout
20 GHz digitizer for UWB
20 GHz DLL for UWB
RF front end chips in CMOS 0.13m, 1.2V
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 48
Conclusions• Proposal based upon UWB impulse radio
– High time resolution suitable for precise ranging using TOA– Modulation:
• Pulse-shape independent• Robust under SOP operation• Facilitates synchronization/tracking• Supports multiple coherent/non-coherent RX architectures
• System tradeoffs– Modulation optimized for several aspects (requirements, performances, flexibility,
technology)– Trade-off complexity/performance RX
• Flexible implementation of the receiver– Coherent, differential, non-coherent (energy collection)– Analogue, digital
• Fits with multiple technologies– Easy implementation in CMOS– Very low power solution (technology, architecture, system level)
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 49
Backup Slides
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 50
BER Performance in AWGN Channel
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
10-5
10-4
10-3
10-2
10-1
Eb/N0
BE
R
MRC Solution (coherent)Differential SolutionEnergy Collection solution in OOK
Transmitted Reference (one pulse)
-3 dB : the “reference” is not in the same PRP !
PER = 1% with 32 bytes PSDU acceptable BER 4x10-5 with no channel coding
Nerrorbiterrorpacketp 11
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 51
BER Performance in AWGN Channel
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 52
Antenna Practicality• Bandwidth: 3 GHz-10 GHz
• Form factor
• Omni-directionaly
x
z
7 mm
ground plane Ø 80 mm
antenna hat Ø 24 mm
-26
-24
-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2 3 4 5 6 7 8 9 10 11 12
|S11| (d
B)
frequency (GHz)
M.S.measured
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 53
Time Difference Of Arrival (TDOA) & One Way Ranging (OWR)
To
Mobile TX
Anchor 1 RX
TOF,1
T1
Anchor 2 RX
TOF,2
T2
Anchor 3 RX
TOF,3
T3
Anchor 1
Anchor 2
Anchor 3
Mobile
Isochronous
Info T2
Info T3
Info T2
Info T3
TOA EstimationTDOA Estimation
cTdTTT
cTdTTT
.~~~
.~~~
23232323
21212121
TDOA Estimation
Passive Location
321 ,, TTT
TOA Estimation
Isochronous
Jan. 2005
CWC/AETHERWIRE/CEA-LETI/STM
doc.: IEEE 802. 15-05-0011-01-004a
Slide 54
Mobile (xm,ym)
Anchor 1 (xA1,yA1)
Anchor 2 (xA2,yA2)
Anchor 3 (xA3,yA3)
Positioning from TDOA
3 anchors with known positions (at least) are
required to find a 2D-position from a couple of TDOAs
2222
31
222232
1133
2233
MAMAMAMA
MAMAMAMA
yyxxyyxxd
yyxxyyxxd
3132
~,
~dd
Measurements Estimated Position
MM yx ~,~Specific Positioning Algorithms