Title: IEEE 802.15 <PHY Proposal>
1Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
Merged UWB proposal for IEEE 802.15.4a
Alt-PHY Date Submitted 13 Mar 2005 Source
Francois Chin, et.al. Company Institute for
Infocomm Research, Singapore Address 21 Heng
Mui Keng Terrace, Singapore 119613 Voice
65-68745687 FAX 65-67744990 E-Mail
chinfrancois_at_i2r.a-star.edu.sg Re Response
to the call for proposal of IEEE 802.15.4a, Doc
Number 15-04-0380-02-004a Abstract Merged
Proposal to IEEE 802.15.4a Task
Group Purpose For presentation and
consideration by the IEEE802.15.4a committee
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.
2This contribution is a technical merger between
- Institute for Infocomm Research 05/032
- General Atomics 05/016
- Thales Cellonics 05/008
- KERI SSU KWU 05/033
- Create-Net China UWB Forum 05/019
- Staccato Communications 04/0704
- Wisair 05/09
For a complete list of authors, please see page
3.
3Authors
- Institute for Infocomm Research
- Francois Chin, Xiaoming Peng, Sam Kwok,
Zhongding Lei, Kannan, Yong-Huat Chew, Chin-Choy
Chai, Rahim, Manjeet, T.T. Tjhung, Hongyi Fu,
Tung-Chong Wong - General Atomics
- Naiel Askar, Susan Lin
- Thales Cellonics
- Serge Hethuin, Isabelle Bucaille, Arnaud
Tonnerre, Fabrice Legrand, Joe Jurianto - KERI SSU KWU
- Kwan-Ho Kim, Sungsoo Choi, Youngjin Park,
Hui-Myoung Oh, Yoan Shin, Won cheol Lee, and
Ho-In Jeon - Create-Net China UWB Forum
- Zheng Zhou, Frank Zheng, Honggang Zhang, Xiaofei
Zhou, Iacopo Carreras, Sandro Pera, Imrich
Chlamtac - Staccato Communications
- Roberto Aiello, Torbjorn Larsson
- Wisair
- Gadi Shor, Sorin Goldenberg
4Multiband Ternary Orthogonal Keying (M-TOK) for
IEEE 802.15.4a UWB based Alt-PHY
5Goals
- Good use of UWB unlicensed spectrum
- Good system design
- Path to low complexity CMOS design
- Path to low power consumption
- Scalable to future standards
- Graceful co-existence with other services
- Graceful co-existence with other UWB systems
- Support different classes of nodes, with
different reliability requirements (and ), with
single common transmit signaling
6Main Features
- Proposal main features
- Impulse-radio based (pulse-shape independent)
- Common preamble signaling for different classes
of nodes / type of receivers (coherent /
differential / noncoherent) - Band Plan based on multiple 500 MHz bands
- Robustness against SOP interference
- Robustness against other in-band interference
- Scalability to trade-off complexity/performance
7Proposed System Parameters
Chip rate 24 Mcps
Pulse / Chip Period 1
Pulse Rep. Freq. 24 MHz
Chip / symbol (Code length) 32
Symbol Rate 24/32 MHz 0.75 MSps
info. bit / sym (Mandatory Mode) 4 bit / symbol
Mandatory bit rate 4 bit/sym x 0.75 MSps 3 Mbps
Code Sequences/ piconet 16 (4 bit/symbol) Code position modulation (CPM)
Lower bit rate scalability Symbol Repetition
Modulation 1,-1 bipolar and 1,-1, 0 ternary pulse train
Total simultaneous piconets supported 6 per FDM band
Multple access for piconets Fixed sequence FDM band for each piconet
8System Description
- Each piconet uses one set of code sequences for
different classes of nodes / type of receivers
(coherent / differential / non-coherent
receivers) - 16 Orthogonal Sequences of code length 32 to
represent a 4-bit symbol - PRF (chip rate) 24 MHz
- Low enough to avoid significant interchip
interference (ICI) with all 802.15.4a multipath
models - High enough to ensure low pulse peak power
- FEC optional (or low complexity type)
9Band Plan
BAND_ID Lower frequency Center frequency Upper frequency
1 3168 MHz 3432 MHz 3696 MHz
2 3696 MHz 3960 MHz 4224 MHz
3 4224 MHz 4488 MHz 4752 MHz
4 4752 MHz 5016 MHz 5280 MHz
5 5280 MHz 5544 MHz 5808 MHz
6 5808 MHz 6072 MHz 6336 MHz
7 6336 MHz 6600 MHz 6864 MHz
8 6864 MHz 7128 MHz 7392 MHz
9 7392 MHz 7656 MHz 7920 MHz
10 7920 MHz 8184 MHz 8448 MHz
11 8448 MHz 8712 MHz 8976 MHz
12 8976 MHz 9240 MHz 9504 MHz
13 9504 MHz 9768 MHz 10032 MHz
14 10032 MHz 10296 MHz 10560 MHz
10Multiple access
- Multiple access within piconet TDMACSMA/CA
- same as 15.4
- Multiple access across piconets CDM FDM
- Different Piconet uses different Base Sequence
different 500 MHz band -
11Types of Receivers Supported
- Coherent Detection The phase of the received
carrier waveform is known, and utilized for
demodulation - Differential Chip Detection The carrier phase of
the previous signaling interval is used as phase
reference for demodulation - Non-coherent Detection The carrier phase
information (e.g.pulse polarity) is unknown at
the receiver
12Criteria of Code Sequence Design
- The sequence Set should have orthogonal (or near
orthogonal) cross correlation properties to
minimise symbol decision error for all the below
receivers - For coherent receiver
- For differential chip receiver
- For non-coherent symbol detection receiver
- Energy detection receiver
- Each sequence should have good auto-correlation
properties
13Criteria of Code Sequence Design
- To minimise impact of DC noise effect on energy
collector based non-coherent receiver - For OOK signaling, the transmitter transmits
1,-1,0 ternary sequences - Conventional receive unipolar code sequence
follows transmit sequence - After the energy capture in the receiver, the
noise has positive DC components in each chip
error occurs in thresholding, especially at lower
SNR - This will accumulate noise unevenly in symbol
decision - An ideal receive despreading chip sequence should
then have bipolar chip values, preferrably with
equal number of 1 and -1 chips - This, to certain extent, will nullify DC noise
energy in symbol decision - This, will also nullify energy components from
other interfering piconets
14Base Sequence Set
Seq 1 0 - - 0 0 0 - 0 0 0 - 0 0 0 0 0 0 - 0 - 0 0 - -
Seq 2 0 - 0 - - 0 0 0 0 0 - 0 0 0 0 0 - 0 0 0 0 - - -
Seq 3 0 - 0 - - - 0 0 0 0 - 0 0 - 0 0 0 0 0 0 - - 0 0
Seq 4 0 0 0 - - 0 - - 0 0 0 - - 0 0 0 - 0 0 0 0 0 0 -
Seq 5 0 - - 0 0 - 0 0 0 0 0 0 0 - - 0 - 0 0 0 0 - - 0
Seq 6 0 0 0 - - 0 0 0 0 0 0 - 0 0 - 0 0 0 0 - - - 0 -
- 31-chip Ternary Sequence set are chosen
- Only one sequence and one fixed band (no hopping)
will be used by all devices in a piconet - Logical channels for support of multiple piconets
- 6 sequences 6 logical channels (e.g.
overlapping piconets) for each FDM Band - The same base sequence will be used to construct
the symbol-to-chip mapping table
15Symbol-to-Chip Mapping Gray coded 16-ary Ternary
Orthogonal Keying
Symbol Cyclic shift to right by n chips, n 32-Chip value
0000 0 0 - - 0 0 0 - 0 0 0 - 0 0 0 0 0 0 - 0 - 0 0 - -
0001 2 0 - - - - 0 0 0 - 0 0 0 - 0 0 0 0 0 0 - 0 - 0 0
0011 4 0 0 0 - - - - 0 0 0 - 0 0 0 - 0 0 0 0 0 0 - 0 -
0010 6 0 - 0 0 - - - - 0 0 0 - 0 0 0 - 0 0 0 0 0 0 - 0
0110 8 0 0 - 0 0 - - - - 0 0 0 - 0 0 0 - 0 0 0 0 0 0
0111 10 0 0 0 0 - 0 0 - - - - 0 0 0 - 0 0 0 - 0 0 0 0
0101 12 0 0 0 0 0 - 0 0 - - - - 0 0 0 - 0 0 0 - 0 0 0
0100 14 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0 - 0 0 0 0
1100 15 0 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0 - 0 0 0
1101 17 0 0 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0 - 0 0
1111 19 0 0 0 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0 - 0
1110 21 0 0 0 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0 - 0
1010 23 0 0 0 0 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0 -
1011 25 0 - 0 0 0 0 0 0 0 0 0 0 - 0 0 - - - - 0 0 0
1001 27 0 0 0 - 0 0 0 0 0 0 0 0 0 0 - 0 0 - - - - 0
1000 29 0 - 0 0 0 - 0 0 0 0 0 0 0 0 0 0 - 0 0 - - -
To obtain 32-chip per symbol, cyclic shift the
Base Sequence first, then append a 0-chip in
front
Base Sequence 1
16Good Properties of the Mapping Sequence
- Cyclic nature, leads to simple implementation
- Zero DC for each sequence
- No need for carrier phase tracking (i.e. coherent
receiver)
17Synchronisation Preamble
Correlator output for synchronisation
- Code sequences has good autocorrelation
properties - Preamble is constructed by repeating 0000
symbols - Long preamble is constructed by further symbol
repetition
18Frame Format
2
1
0/4/8
2
n
Octets
Data Payload
Frame Cont.
MAC Sublayer
Seq.
Address
CRC
MHR
MSDU
MFR
Data 32 (n23)
4?
1
1
For ACK 5 (n0)
Octets
PHY Layer
Frame Length
Preamble
SFD
MPDU
SHR
PHR
PSDU
PPDU
19Transmission Mode
Mode Data Rate (Mbps) Bit / symbol Sym. Rep. TX Sign-aling Receiver type
1a 3 4 1 Ternary - Short Preamble for all receivers - High Data Rate Mode (for Energy Collection receivers)
1b 0.75 4 4 Ternary - Long Preamble for all receivers - Low Data Rate Mode (for Energy Collection receivers)
2a 3 4 1 Binary - High Data Rate Mode (for Coherent / Differential Chip Receiver)
2b 0.75 4 4 Binary - Low Data Rate Mode (for Coherent / Differential Chip Receiver)
20Modulation Coding (Mode 1)
Binary data From PPDU
Symbol- to-Chip
Bit-to- Symbol
Symbol Repetition
Pulse Generator
0,1,-1 Ternary Sequence
- Bit to symbol mapping
- group every 4 bits into a symbol
- Symbol-to-chip mapping
- Each 4-bit symbol is mapped to one of 16 32-chip
sequence, according to 16-ary Ternary Orthogonal
Keying - Symbol Repetition
- for data rate and range scalability
- Pulse Genarator
- Transmit Ternary pulses at PRF 24MHz
21Modulation Coding (Mode 2)
Binary data From PPDU
Symbol- to-Chip
Pulse Generator
Bit-to- Symbol
Symbol Repetition
Ternary- Binary
1,-1 Binary Sequence
0,1,-1 Ternary Sequence
- Bit to symbol mapping
- group every 4 bits into a symbol
- Symbol-to-chip mapping
- Each 4-bit symbol is mapped to one of 16 32-chip
sequence, according to 16-ary Ternary Orthogonal
Keying - Symbol Repetition
- for data rate and range scalability
- Ternary to Binary conversion
- (-1/1 ? 1,0 ? -1)
- Pulse Genarator
- Transmit bipolar pulses at PRF 24MHz
22Code Sequence Properties Performance
- AWGN Performance
- Multipath Performance
- For Coherent Symbol Detector
- For Non-coherent Symbol Detector
- For Differential Chip Detector
- For Energy Detector
23AWGN Performance
24AWGN Performance
- AWGN performance _at_ 1 PER
_at_ 3 Mbps Coherent symbol detection Non-coherent symbol detection Differential chip detection Energy detection
Mode 1 6.5 dB 8.5 dB 13 dB 13.5 dB
Mode 2 6.5 dB 7.5 dB 11.5 dB -
25Auto Correlation Properties for
Coherent/Non-Coherent Symbol Detector
26Cross Correlation Properties for
Coherent/Non-Coherent Symbol Detector
TxSeqSet RxSeqSet' (Mode 2)
TxSeqSet RxSeqSet' (Mode 1)
27Multipath Performance for Coherent Symbol Detector
28Multipath Performance for Non-Coherent Symbol
Detector
29Auto Correlation Properties for Differential
Chip Detector
30Cross Correlation Properties for Differential
Chip Detector
DifferentialChip(TxSeqSet) DifferentialChip(RxS
eqSet) (Mode 2)
DifferentialChip(TxSeqSet) DifferentialChip(RxS
eqSet) (Mode 1)
31Multipath Combining for Differential Chip Detector
32Multipath Performance for Differential Chip
Detector
33Non-Coherent Receiver Architectures (Mode 1)
LPF / integrator
Soft Despread
BPF
( )2
ADC
Sample Rate 1/Tc
- Energy detection technique rather than coherent
receiver, for low cost, low complexity - Soft chip values gives best results
- Oversampling sequence correlation is used to
recovery chip timing recovery - Synchronization fully re-acquired for each new
packet received (gt no very accurate timebase
needed)
34Auto Correlation Properties for Energy Detection
Receiver
35Cross Correlation Properties for Energy
Detection Receiver
TxSeqSet RxSeqSet '
36Multipath Performance for Energy Detector
37Basic Data Rate Throughput (Low Rate Modes)
- Useful data rate calculation for 32 byte PSDU (Xo
0.75 Mbps) - Symbol Period 1.33us
- Data frame time 38 x 8 / 0.75 405.3 µsec
- ACK frame time 11 x 8 / 0.75 117.3 µsec
- tACK (considering 15.4 spec) 192 µsec
- LIFS (considering 15.4 spec) 640 µsec
- Tframe 1355 µsec
- Useful Basic Data Rate 189.0 kbps
38Basic Data Rate Throughput (High Rate Modes)
- Useful data rate calculation for 32 byte PSDU (Xo
3 Mbps) - Symbol Period 1.33us
- Data frame time 38 x 8 / 3 101.3 µsec
- ACK frame time 11 x 8 / 3 29.3 µsec
- tACK (considering 15.4 spec) 192 µsec
- LIFS (considering 15.4 spec) 640 µsec
- Tframe 963 µsec
- Useful Basic Data Rate 265.9 kbps
39Basic Data Rate Throughput (High Rate Modes)
- Useful data rate calculation for 127 byte PSDU
(Xo 3 Mbps) - Symbol Period 1.33us
- Data frame time 127 x 8 / 3 354.7 µsec
- ACK frame time 11 x 8 / 3 29.3 µsec
- tACK (considering 15.4 spec) 192 µsec
- LIFS (considering 15.4 spec) 640 µsec
- Tframe 1216 µsec
- Useful Basic Data Rate 853.5 kbps
40Link Budget
41Ranging and Positioning
42Asynchronous Ranging Scheme
- Synchronous ranging
- One way ranging
- Simple TOA/TDOA measurement
- Universal external clock
- Asynchronous ranging
- Two way ranging
- TOA/TDOA measurement by RTTs
- Half-duplex type of signal exchange
TOF Time Of Flight RTT Round Trip Time SHR
Synchronization Header
But, High Complexity
Asynchronous Ranging
Synchronous Ranging
43Features- Sequential two-way ranging is executed
via relay transmissions- PAN coordinator manages
the overall schedule for positioning- Inactive
mode processing is required along the
positioning- PAN coordinator may transfer all
sorts of information such as observed - TDOAs to
a processing unit (PU) for position
calculationBenefits- It does not need
pre-synchronization among the devices-
Positioning in mobile environment is partly
accomplished
Proposed Positioning Scheme
P_FFD3
P_FFD2
TOA
24
TOA
34
RFD
PAN
coordinator
TOA
14
PU
P_FFD Positioning Full Function Device
RFD Reduced Function Device
P_FFD1
44Process of Proposed Positioning Scheme
TOA measurement
45More Details for obtaining TDOAs
- Distances among the positioning FFDs are
calculated from RTT measurements and known time
interval T - Using observed RTT measurements and calculated
distances, TOAs/TDOAs are updated
T12 (RTT12 T)/2
T23 (RTT23 T)/2
T13 (RTT13 T12 T23 2T)
RTT34 T34 T T34
TOA34 (RTT34 - T)/2
RTT24 T23 T T34 T T24
TOA24 (RTT24 - T23 - TOA34 - 2T)
RTT14 T12 T T23 T T34 T T14
TOA14 (RTT14 - T12 - T23 - TOA34 - 3T)
TDOA12 TOA14 TOA24
TDOA23 TOA24 TOA34
46Position Calculation using TDOAs
- The range difference measurement defines a
hyperboloid of constant range difference - When multiple range difference measurements are
obtained, producing multiple hyperboloids, the
position location of the device is at the
intersection among the hyperboloids
47Positioning Scenario Overview
- Using static reference nodes in relatively large
scaled cluster - Power control is required
- Power consumption increases
- All devices in cluster must be in inactive data
transmission mode - Using static and dynamic nodes in overlapped
small scaled sub-clusters - Sequential positioning is executed in each
sub-cluster - Low power consumption
- Associated sub-cluster in positioning mode should
be in inactive data transmission mode
Cluster 1
Cluster 1
48Positioning Scenario for Star topology
- Star topology
- PAN coordinator activated mode
- Positioning all devices
- Re-alignment of positioning FFDs list is not
required - Target device activated mode
- Positioning is requested from some device
- Re-alignment of positioning FFDs list is
required -
49Positioning Scenario for Cluster-tree Topology
50Ranging Accuracy Improvement
- Technical requirement for positioning
- It can be related to precise (tens of
centimeters) localization in some cases, but is
generally limited to about one meter - Parameters for technical requirement
- Minimum required pulse duration
- Minimum required clock speed for the correlator
in the conventional coherent systems
High Cost !
- Fast ADC clock speed in the conventional coherent
receiver is required for the digital signal
processing
51Analog Energy Window Bank (1)
- Digital signal processing with fast clock can be
replaced by using analog energy window bank with
low clock speed - Why analog energy window bank?
- Conventional single energy window may support the
energy detection for data demodulation in the
operation mode - However, this cannot guarantee the correct
searching of the signal position in the timing
mode (that also means the ambiguity of ranging
accuracy) - Analog energy window bank can sufficiently
support timing and calibration as well as
operation mode - Widow Bank Size 4 nsec (smallest pulse
duration) - The number of energy windows in a bank 11
- Operation clock speed of each energy window 24
MHz - Number of the required energy windows depends on
the power delay profile of the multipath channel
(effective multipath components)
52Analog Energy Window Bank (2)
53Modifying MAC
54Modifications of MAC Command Frame (1)
- Features
- Frame control field
- frame type positioning (new addition using a
reserved bit) - Command frame identifier field
- Positioning request/response (new addition)
- Positioning parameter information field
- Absolute coordinates of positioning FFDs
- POS range
- List of positioning FFDs and target devices
- Power control
- Pre-determined processing time (T)
Octets 2 1 0/4/8 1 variable variable 2
Frame control Sequence number Addressing fields command frame identifier Positioning parameter Command payload FCS
MHR MHR MHR MAC payload MAC payload MAC payload MFR
55Modifications of MAC Command Frame (2)
bits 02 3 4 5 6 79 1011 1213 1415
Frame type Security enabled Frame pending Ack. request Intra- PAN Reserved Dest. addressing mode Reserved Source addressing mode
Frame type value Description
000 Beacon
001 Data
010 Acknowledgment
011 MAC command
100 Positioning
101111 Reserved
Command frame identifier Command frame
0x01 Association request
0x02 Association response
0x03 Disassociation notification
0x04 Data request
0x05 PAN ID conflict notification
0x06 Orphan notification
0x07 Beacon request
0x08 Coordinator realignment
0x09 GTS request
0x0a Positioning request
0x0b Positioning response
0x0c0xff Reserved
Fixed coordinate POS range positioning FFDs Address Target devices lists Pre-determined processing time(T) Power Control
56Summary
- The proposed system
- Impulse-radio based system coupled with a Common
ternary signaling allows operation among
different classes of nodes / type of receivers,
with varying cost / power / performance trade-off - Has Band Plan based on multiple 500MHz bands
- Is robust against SOP interference
- Is robust against other in-band interference