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Transcript of Doc.: IEEE 15-05-0344-01-004a TG4a June 30th, 2005 Gian Mario Maggio & Philippe Rouzet (STM)Slide 1...
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 1
doc.: IEEE 15-05-0344-01-004a
TG4a
Project: IEEE P802.15 Working Group for Wireless Personal Area Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Networks (WPANs)
Submission Title: TG4a Review of Proposed UWB-PHY Modulation Schemes and Selection Criteria
Date Submitted: June 30th, 2005Source: Gian Mario Maggio & Philippe Rouzet (STMicroelectronics)Contact: Gian Mario MaggioVoice: +41-22-929-6917, E-Mail: [email protected]: Review of modulations/waveforms for TG4a UWB-PHY standard and
proposed selection criteriaPurpose: To provide information for further investigation on and selection of the
modulation/waveforms for the UWB-PHYNotice: 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.
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 2
doc.: IEEE 15-05-0344-01-004a
TG4a
IEEE 802.15.4a:UWB-PHY Modulation
UWB-PHY Modulation SubgroupGian Mario Maggio & Philippe Rouzet
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 3
doc.: IEEE 15-05-0344-01-004a
TG4a
List of Contributors/Documents
• Gian Mario Maggio & Philippe Rouzet - STMicroelectronics (#15-05-0217-00-004a, #15-05-0243-00-004a, #15-05-0325-00-004a)• Laurent Ouvry et al. – CEA-LETI (#15-05-0354-01-004a)• Michael Mc Laughlin – Decawawe (#15-05-0359-00-004a)• Matt Welborn – Freescale (#15-05-0240-02-004a)• Francois Chin et al. – I2R (#15-05-0231-03-004a)• Huang-Ban Li et al. – NICT (#15-05-0300-00-004a)• Ismail Lakkis & Saeid Safavi – Wideband Access (#15-05-0250-03-004a, #15-05-0355-00-004a) • Phil Orlik, Andy Molisch et al. - MERL (#15-05-0291-00-004a)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 4
doc.: IEEE 15-05-0344-01-004a
TG4a
Topics for Discussion
1. Pulse shaping2. Modulation formats3. Waveform design4. Design parameters5. Adaptive modulation & coding6. Selection Criteria
7. Receiver Architecture8. Simulation Results
ACTION LIST UWB-PHY GROUP
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 5
doc.: IEEE 15-05-0344-01-004a
TG4a
UWB-PHY: Introduction
• Impulse-radio based (pulse-shape independent)
• Support for different RX architectures: – Coherent– Differentially-coherent– Non-coherent
• Support for multiple rates• Support for SOP
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 6
doc.: IEEE 15-05-0344-01-004a
TG4a
Parameter Definition
Chip The minimum time resolution of a UWB signal, whose rate is considered as the minimum sampling rate of the signal (complying with the Nyquist sampling theorem), i.e. closest allowable distance between successive pulses
Pulse A radiated short transient UWB signal whose time duration is associated with the reciprocal of its UWB -10 dB BW , i.e. the shortest waveform
Effective PulseWidth
An interval which is defined by the effective portion of the pulse energy with a time duration which is the reciprocal of the -10 dB BW of the UWB signal
Burst Group of Pulses
Symbol Group of Bursts
Channel Separation
The difference between the center frequencies of each channel (its relation to chip rate is not yet defined)
PRF The frequency of repetition of Pulses if there is one pulse per Burst. If there is more than one Pulse per Burst the PRF is defined as the frequency of repetition of Bursts (group of pulses)
PRI Reciprocal of PRF
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 7
doc.: IEEE 15-05-0344-01-004a
TG4a
Illustration of Pulse and Chip Definitions
One Pulse
One Chip
PULSE: shortest waveform
CHIP: closest allowable distance between successive pulses
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 8
doc.: IEEE 15-05-0344-01-004a
TG4a
Symbol (1 or more bursts)
EffectivePulse
Duration
-3 dB
-10 dB
-20 dB
-30 dB
-40 dB
-50 dB
-60 dB
-70 dB
3 dB BW
10 dB BW
Pulse Repetition Interval (PRI, assuming one burst per symbol)
Inverse Relation PRF
Burst(1 or more pulses)
Pulse
Inverse Relation
ChipDuration
Symbol Duration
Burst DurationPulse Duration
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 9
doc.: IEEE 15-05-0344-01-004a
TG4a
Pulse Shaping Pulse shape:
a) Gaussianb) Raised cosinec) Chaotic d) Chirp….• Optional: Variable pulse shapes with SSA (Soft
Spectrum Adaptation)Pulse duration: Lower bound set by bandwidth
occupation (e.g. 500 MHz); Upper bound may be set according to design considerations
Pulse amplitude: Peak-to-peak voltage limited by CMOS technology
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 10
doc.: IEEE 15-05-0344-01-004a
TG4a
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- or as an amplitude detector
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 11
doc.: IEEE 15-05-0344-01-004a
TG4a
Pros/Cons of RX Architectures
Coherent+ : Sensitivity+ : Use of polarity to carry data+ : Optimal processing gain achievable- : Complexity of channel estimation and RAKE receiver
Differentially-Coherent (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
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 12
doc.: IEEE 15-05-0344-01-004a
TG4a
Modulation Format(s)
• Simple, scalable modulation format• One mandatory mode plus one or more
optional modulation modes• Modulation compatible with multiple
coherent/non-coherent receiver schemes Flexibility for system designer
• Time hopping (TH) for spectral smoothing and to permit multiple access
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 13
doc.: IEEE 15-05-0344-01-004a
TG4a
Time Hopping-IR: Basics
Ts
Tc
Tf
+1
-1
• Each symbol represented by sequence of very short pulses• Each user uses different PN sequences (for multiple access)• Spectrum mostly determined by pulse shape
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 14
doc.: IEEE 15-05-0344-01-004a
TG4a
Waveform Design
• Combination of (outer) TH and BPPM, combined with BPSK/DBPSK
• Guarantee coexistence of coherent and non-coherent RX architectures:– Non-coherent receivers just look for energy in the early or
late slots to decode the bit (BPPM); OOK receiver may be used to demodulate BPPM symbol as well
– Coherent and differentially-coherent receivers, in addition, understand the fine symbol structure (BPSK or DBPSK)
• Principle: Non-coherent and differentially-coherent modes should not penalize coherent-RX performance
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 15
doc.: IEEE 15-05-0344-01-004a
TG4a
RX Coexistence
Rake Receiver
Finger Np
Rake ReceiverFinger 2
Rake ReceiverFinger 1
Summer
Td
0
Coherent RX
Differentially-Coherent RX
TX
( )2
Non-Coherent RX
Pulse Gen.
TH SeqBPSK symbol mapper
BPSK symbol mapper
Delay
Central Timing Control
Multipl
exer
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 16
doc.: IEEE 15-05-0344-01-004a
TG4a
Mitigation of Peak-Voltage through Multi-Pulses
Tf=PPI
Tf=PPI
IS « EQUIVALENT » TO
ppV = peak-to-peak voltage
ppV/2M = 4
M = 1
Tf=PPI
ppV/sqrt(2)
M = 2
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 17
doc.: IEEE 15-05-0344-01-004a
TG4a
BPPM Symbol Structure
1. Doublet-based symbolRealization 1a: TH-IR + TR(the whole TR symbol is BPPM modulated)
Realization 2a: TR + Inner TH (apply TH code to each frame)
Realization 3a: Diff. encoding + Inner TH (doublets with memory from previous bit)
2. Burst-based symbolRealization 2a: Generalized TR(one reference pulse, multiple information pulses)
Realization 2b: “CDMA-like” burst(burst of pulses, modulated by a spreading code)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 18
doc.: IEEE 15-05-0344-01-004a
TG4a
(1) Transmitted-Reference: Basics
• First pulse serves as template for estimating channel distortions• Second pulse carries information• Drawback: Waste of 3dB energy on reference pulses
Tddata
Ts
TcTf
+1
-1
reference
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 19
doc.: IEEE 15-05-0344-01-004a
TG4a
(1a) Example - Signal Waveforms
Ts
« 11 »
« 01 »2-PPM + TR baseM = 2(with two bits/symbol) « 10 »
« 00 »
(coherent decoding possible) 2-PPM + 16 chips 2-ary TH code
• Time hopping code is (2,2) code of length 8/16, can be exploited by non-coherent RX• Effectively, 28 or 216 codes to select for channelization for non-coherent scheme
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 20
doc.: IEEE 15-05-0344-01-004a
TG4a
(1a) Detailed Symbol Structure
Ts
« 0 »
Td
negative
positive
Same polarity : bit = 0
ThInner time hop of Tdelta = 2 Th
Outer time hop of Tc = Tf/2 = n*Th
Same polarity : bit = 0
Tc
Tf
Tdelay
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 21
doc.: IEEE 15-05-0344-01-004a
TG4a
(1b) Example - Signal Waveforms
Ts
« 11 »
« 01 »2-PPM + TR baseM = 2
One bit/symbol « 10 »
« 00 »
(coherent decoding possible) 2-PPM + 16 chips 2-ary TH codeor 2-PPM + 8 chips 4-ary TH code
• Time hopping code is (2,2) code of length 8/16, can be exploited by non-coherent RX• Effectively, 28 or 216 codes to select for channelization for non-coherent scheme
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 22
doc.: IEEE 15-05-0344-01-004a
TG4a
(1b) Detailed Symbol StructureTs
« 0 »
Tx
Td negative
positive
Same polarity : bit = 0
ThInner time hop of Tdelta = 2 Th+ inner polarity hop
Outer time hop of Tc = Tf/2 = n*Th
Same polarity : bit = 0
Tc
Tf
Tx Tdelay
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 23
doc.: IEEE 15-05-0344-01-004a
TG4a
(1c) Differential Encoding: Basics
Ts
+1 -1 +1 -1 +1 -1
-1 -1 +1 +1 -1 -1
0 0 1 1 0 0 1
b0 b4b3b2b1 b5b-1
Tx Bits
Reference Polarity
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 24
doc.: IEEE 15-05-0344-01-004a
TG4a
(1c) Example - Signal Waveformsbi-1 = 1, bi = 1
bi-1 = 0, bi = 1
bi-1 = 0, bi = 0
bi-1 = 1, bi = 0
• Use of doublets with memory from previous bit (encoding of reference pulse with previous bit)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 25
doc.: IEEE 15-05-0344-01-004a
TG4a
(2a) Generalized TR
TH PatternTH Code 1,1 1,1 0,1 0,0 1,0 0,1Data 1,1 1,1 1,1 1,1 1,1 0,0
Pulse Shift, polarity invert
τΔ + τdelay
Enhanced Mode
D« 1 1 »
« 1 0 »
D D τdelay +τΔ
τΔ τdelay τΔ + τdelayτdelayτΔτΔ + τdelay τΔ + τdelay
Basic Mode (as seen by non-coherent)
« 1 »τdelay +τΔD D D
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 26
doc.: IEEE 15-05-0344-01-004a
TG4a
(2b) “CDMA-Like” BurstSimilar 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
One BPPM symbol
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 27
doc.: IEEE 15-05-0344-01-004a
TG4a
(2b) Example 1: 31-Chip Code
Symbol Cyclic shift to right by n chips, n=
31-Chip value
00 0 + - - 0 0 0 + - 0 + + + 0 + 0 - 0 0 0 0 + 0 0 - 0 - + 0 0 - -
01 8 - 0 - + 0 0 - - + - - 0 0 0 + - 0 + + + 0 + 0 - 0 0 0 0 + 0 0
11 16 - 0 0 0 0 + 0 0 - 0 - + 0 0 - - + - - 0 0 0 + - 0 + + + 0 + 0
10 24 - 0 + + + 0 + 0 - 0 0 0 0 + 0 0 - 0 - + 0 0 - - + - - 0 0 0 +
• Can support both coherent and non-coherent pulse compression
• Add 33 zero chips to get baseline mode for non-coherent receivers
Note: In general, careful code design is needed for spectral shaping
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 28
doc.: IEEE 15-05-0344-01-004a
TG4a
(2b) Example 2: Spreading via Scrambling
• Scrambling = time varying spreading• Use a single (set) scrambler of length (ex: 32768) and assign a
different offset (of 16 or 32) to different nodes• For ternary modulation invert sequence when transmitting a 0• Number of users supported is 1024• Perfect co-channel interference rejection• Support virtually any data rate from 16MHz to 32 Kbps for a PRF of
16MHz• Spectrum is virtually flat (no back-off)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 29
doc.: IEEE 15-05-0344-01-004a
TG4a
(2b) Example 2: Ternary Modulator
Scramblerspreader
PRF rate (ex: 16MHz)
Data @ Data-Rate (ex: 2Mbps) On-off pulses @
PRF rate (2Mbps) On-off to Ternary1 : +/-0: 0
Ternary pulses @ PRF rate (2Mbps)
0 1 1 0 1 0 0 1 1 0 0 0 1 1 0 1
1 0
0 1 1 0 1 0 0 1 0 1 1 1 0 0 1 0
Data bits
Scrambler output
On-off pulses
0 + - 0 - 0 0 + 0 + + - 0 0 - 0Ternary pulses
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 30
doc.: IEEE 15-05-0344-01-004a
TG4a
(2b) Example 2: Ternary Receiver
BPF LNA ( )2 1 bitADC
On-off toBPSK
Scramblerdespreader
BPSKcorrelator
On-off toBPSK
+ - - - + + - +
8 -8
0 1 1 0 1 0 0 1 0 1 1 1 0 0 1 0
Correlator output
BPSK Scrambler output
Received on-off pulses
- + + - + - - + - + + + - - + -On-off to BPSK
- + + - + - - +
1b ADC : requires threshold training during preamble3b ADC : does not requires thresholding (soft correlator)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 31
doc.: IEEE 15-05-0344-01-004a
TG4a
(2b) Example 2: BPSK Modulator/Receiver
• ADC from 1 bit to multiple bits• BPSK correlator• Time varying spreading improves interference rejection
tremendeously
BPF LNALow Rate
Limiter
Scramblerdespreader
BPSKcorrelator
On-off toBPSK
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 32
doc.: IEEE 15-05-0344-01-004a
TG4a
Design Parameters (1/3) • Pulse Repetition Period (PRP)
– Realization #1:1a) PRP = 100 ns1b) PRP = 40 ns1c) PRP = 40 ns
• Burst Repetition Period (BRP)– Realization #2:
2a) BRP ≥ 200 ns2b) BRP = 436 ns
• Inter-pulse interval:– Minimum: ~5 ns (technology constraint)– Realization #1: ~20 ns– Realization #2(b): ~4.5 ns
Note (TR): Max realizable analog delay ~10 ns
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 33
doc.: IEEE 15-05-0344-01-004a
TG4a
Design Parameters (2/3)
• Time-hopping:– TH code (outer): 2-ary (or M-ary in general, for
better SOP support) of length 4-16; granularity level ~Tf/2 (or Tf/M)
– Inner TH code (Realization #1b,c): Apply inner TH code (frame-by-frame) down to 2 ns (or multiples) granularity level
• Polarity hopping: May be applied on top, for spectral smoothing
purposes and/or signals separation
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 34
doc.: IEEE 15-05-0344-01-004a
TG4a
Design Parameters (3/3)
• Channelization– Coherent schemes: Use of TH codes and polarity
codes– Non-coherent schemes: Use of TH codes (polarity
codes for spectrum smoothing only)Realization 2b): CDMA
• Multi-access capabilities:– Max # of coexisting users within piconet
• SOP support:– Up to 6 SOP/band
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 35
doc.: IEEE 15-05-0344-01-004a
TG4a
Adaptive Modulation & Coding
1. Adaptive modulation: Enhanced modes (available for coherent receiver)
2. Adaptive PRP: Two PRP values supported
3. Adaptive processing gain: Variable TH code length (variable number of pulses/bit)
4. Adaptive coding rate (e.g. by acting on the puncturing associated with a convolutional code)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 36
doc.: IEEE 15-05-0344-01-004a
TG4a
Optional: Encoding of “Extra”-Bits
• Example: Rate-½ convolutional encoder– Produce multiple coded bits from each data bit
• Special case of convolutional code is a “systematic” code– First coded bit is same as input data bit– Second coded bit is computed by encoder
• Mapping coded bits to waveform– Map first coded bit (systematic bit) into position for BPPM– Map second coded bit into TR symbol
• Can be extended to more general (non-systematic) codes very easily
x2
x1=bkbk
ConvolutionalEncoder
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 37
doc.: IEEE 15-05-0344-01-004a
TG4a
(3) CS-UWB
Time
Am
plitu
de
Am
plitu
de
Frequency
Time
Fre
quen
cy
Pulse signal
• Chirp Signaling-UWB can be generated by passing a pulse signal through a distributed delay line (DDL) such as a SAW DDL:
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 38
doc.: IEEE 15-05-0344-01-004a
TG4a
(3) Correlated Processing• Correlated processing produces not only high
precision ranging but also robustness against noise and multipath
Cor
rela
tor
outp
ut
Correlated processing
Time shift[s]
The wide the bandwidth, the sharp the peak.
B: 3-dB bandwidth of chirpT: time interval of chirp
T
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 39
doc.: IEEE 15-05-0344-01-004a
TG4a
(3) Advantages of Chirp Signaling
• High capacity for SOP – Plenty of source with chirp– Combination with FDM and/or CDM
• Additional link margins – Low peak-to-average ratio
• Robustness against interference and multipath– Excellent correlation characteristics
• Potential high precision ranging. – Excellent correlation characteristics
• An selectivity for FFD and RFD – Chirp vs. non-chirp
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 40
doc.: IEEE 15-05-0344-01-004a
TG4a
Proposed Selection Criteria (in decreasing priority order)
1. PER (packet error rate) performance @1Mb/s with 15.4a channel models, CMOS-compatible peak-to-peak voltage, rate ½ convolutional code (constraint length up to 5; more needs justification):
1.a) Coherent receiver 1.b) Diff. coherent receiver 1.c) Non-coherent receiver
2. SOP isolation (at least 2 SOP/band; up to 6 SOP)3. Spectrum: SPAR (spectral peak-to-average ratio)
4. Receiver flexibility: Support for coherent, diff. coherent and non-coherent RX
5. Scalability: Trade-off performance vs. complexity
6. Resilience to NBI (narrow-band interference)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 41
doc.: IEEE 15-05-0344-01-004a
TG4a
ANNEX(Extra-Slides: Support for Discussion)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 42
doc.: IEEE 15-05-0344-01-004a
TG4a
Coherent Receiver: RAKE Receiver
Rake ReceiverFinger Np
Demultiplexer Rake ReceiverFinger 2
Rake ReceiverFinger 1
Summer
Channel Estimation
Convolutional Decoder Data
Sink
Sequence Detector
• Addition of Sequence Detector – Proposed modulation may be viewed as having memory of length 2• Main component of Rake finger: pulse generator• A/D converter: 3-bit, operating at symbol rate• No adjustable delay elements required
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 43
doc.: IEEE 15-05-0344-01-004a
TG4a
Differentially-Coherent Receiver(for Transmitted Reference)
Td
0
MatchedFilter
Convolutional Decoder
• Note: Addition of Matched Filter prior to Delay & Correlation operations improves output SNR and reduces noise-noise cross terms
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 44
doc.: IEEE 15-05-0344-01-004a
TG4a
Non-Coherent Receiver (Energy Collector)
Band MatchedBand Matched
LNALNALNALNA BPFBPF
TrackingTrackingThresholThreshol
ds ds settingsetting
TrackingTrackingThresholThreshol
ds ds settingsetting
DumpDumpLatchLatchDumpDumpLatchLatch
RA
ZR
AZ
DUMPDUMP
ControlledControlledIntegratorIntegrator
ADCADC
BPPM Demodulation BPPM Demodulation branchbranch
RAZRAZ
x2 x2r(t)
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 45
doc.: IEEE 15-05-0344-01-004a
TG4a
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 de-spreading
ADCADC
ADCADCb(t)
soft info
Case II – Non-coherent / differential TH despreading
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 46
doc.: IEEE 15-05-0344-01-004a
TG4a
• Idea: Transmitted-reference BPSK symbol can be decoded by a non-coherent detector (like OOK symbol)
• Advantages: Differential and non-coherent receiver may coexist• Concept can be generalized to N-ary TR-BPSK
TR-BPSK Non-Coherent Detection
Pulse MatchedPulse Matchedf(t) s(t)
r(t)“0”
“1”“1”
“0”
LNALNALNALNA
DelayDelayDD
DelayDelayDD
BPFBPF
D
Non-Coherent DetectorNon-Coherent Detector(Energy Collection)(Energy Collection)
-SynchroSynchroTrackingTracking
ThresholdThresholds settings setting
SynchroSynchroTrackingTracking
ThresholdThresholds settings setting
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 47
doc.: IEEE 15-05-0344-01-004a
TG4a
TR-BPPM Schemes Comparison (1/2)
Notes:• Results are theoretical calculations• Assumes ideal ”impulse” UWB pulses in
AWGN channel• Different TR-BBPM options are considered
with different number of pulses per pulse train• Multipath fading simulations can be performed
to back up theory
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 48
doc.: IEEE 15-05-0344-01-004a
TG4a
TR-BPPM Schemes Comparison (2/2)
• Parameters:– PPI slot - slot inside each TH chip containing a
burst of pulses including reference pulses
– Np represents the number of pulses in each PPI slot
– The energy E per PPI slot is kept constant
– The pulse energy Ep = E/Np
– TW represent the time-bandwidth product
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 49
doc.: IEEE 15-05-0344-01-004a
TG4a
Pulse Repetition Structures- Scheme 1TR-BPPM with doublets
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 50
doc.: IEEE 15-05-0344-01-004a
TG4a
Pulse Repetition Structures - Scheme 2TR-BPPM single reference
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 51
doc.: IEEE 15-05-0344-01-004a
TG4a
Pulse Repetition Structures - Scheme 3Auto Correlation BPPM with doublets
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 52
doc.: IEEE 15-05-0344-01-004a
TG4a
Pulse Repetition Structures - Scheme 4Auto Correlation BPPM single reference
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 53
doc.: IEEE 15-05-0344-01-004a
TG4a
Pulse Repetition Structures - Scheme 5Auto Correlation BPPM alternate
• Scheme 5: “AC Alternate” performs better then all the other pulse repetition structures• AC generally performs better than TR• “AC alternate” and “AC with doublets” require a single delay
June 30th, 2005
Gian Mario Maggio & Philippe Rouzet (STM)Slide 54
doc.: IEEE 15-05-0344-01-004a
TG4a
Overall Block Diagram With Optional CS
Coding &modulation Coding &
modulation SpreadingSpreading
Pre-SelectFilter
LNALNA
Transmitter
Receiver
CHIRPCHIRP
De-CHIRP
De-CHIRP
PulseshapingPulse
shaping GAGA
Local oscillator
Local oscillator
BW = 500MHz or 2GHz
Additional circuits to DS-UWB as an option
Ranging data
Comm.data
LPFLPF
LPFLPF
GAGA
GAGA
1 or 2-bit ADC
1 or 2-bit ADC
1 or 2-bitADC
1 or 2-bitADC
Sync.Sync.Local
oscillatorLocal
oscillator
Decision/FEC
decoder
Decision/FEC
decoder
I
QTime base
Peak detection
Ranging data
Calculation
Comm.data
Ranging processing