1. Submission Title: [Revised Frequency Plan and PRF Proposal for TG4a]
11/23/2018
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Revised Frequency Plan and PRF Proposal for TG4a]
Date Submitted: [27 April 2005]
Source: [Ismail Lakkis & Saeid Safavi, Wideband Access Inc.]
Contact: Saeid Safavi.
Voice:[ ,
Abstract: [Ban Plan, PRF, Preamble & Modulation]
Purpose: [Clarification of relationship between minimum PRF and maximum allowed voltage level in UWB IR]
Notice: This document has been prepared to assist the IEEE P 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 P
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

2. Agenda Proposed system features Frequency Plan / PRF Preamble
11/23/2018
Agenda
Proposed system features
Frequency Plan / PRF
Preamble
Modulation
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

3. Frequency Plan / PRF 11/23/2018 Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

4. Proposed System Features
11/23/2018
Proposed System Features
Meets requirements for TG4a baseline draft
Frequency plan with simple PLL structure and safe margins to 3.1GHz and 4.9 GHz
Support of a range of PRFs (low and high)
Impulse-radio system
Common preamble structure for different classes of nodes/receivers type ( coh./noncoh.) & ranging
Flexible adaptive data rate
Robustness against SOP interference through frequency and code division
Robustness against other in-band interference
Scalability to trade-off complexity/performance
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

5. Frequency Plan Requirements
11/23/2018
Frequency Plan Requirements
Requirements
Sub-banding (Three bands) with mandatory center band of ~500MHz and an optional wider co-centric band of ~1.5GHz
Mandatory: FCC spectral 3.1GHz  at least 10 dB attenuation constraint on filtering
Desirable: co-existence with 4.9GHz
Implications
A safe margin to 3.1GHz to meet FCC requirement
For IR system using a pulser (no mixer), the BPF is responsible for the 3.1GHz corner filtering
A safe margin to 4.9GHz to coexist with WLAN
Different frequencies should be easily generated from the system PLL with first divisions in powers of 2
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

6. PRF Requirements Requirements Implications
11/23/2018
PRF Requirements
Requirements
Support of multiple (at least 2) PRF in band
Limit on lowest possible PRF due to CMOS 90 nm technology
Limit on highest possible PRF due to inter-frame interference for a non-coherent receiver
Implications
Supported PRFs should be easily derived from the PLL through simple divisions
Low PRF as base PRF
High PRF as second PRF
PRF should be high enough to take advantage of FCC rules
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

7. Relationship between PRF & Peak Power
11/23/2018
Relationship between PRF & Peak Power
VPeak TC
PRI
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

8. Minimum PRF vs Peak Power (CMOS 90nm)
11/23/2018
Minimum PRF vs Peak Power (CMOS 90nm)
BW = 500 MHz
Technology
CMOS 90nm 2.5 Vpp, BPSK
CMOS 90nm 2.5 Vpp, Ternary
TChip (nsec) 2
BW (MHz)
500
VPeak (v)
1.25
PAve (dBm)
-14.31
PPeak (dBm)
11.94
PRF VPeak (No Margin)
1.19
2.37
PRF VPeak (8 dB Margin)*
7.48
14.97
BW = 1500 MHz
Technology
CMOS 90nm 2.5 Vpp, BPSK
CMOS 90nm 2.5 Vpp, Ternary
TChip (nsec)
0.66
BW (MHz)
1500
VPeak (v)
1.25
PAve (dBm)
-9.54
-9.45
PPeak (dBm)
11.94
PRF VPeak (No Margin)
10.67
21.35
PRF VPeak (4.5 dB Margin)
30.09
60.17
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

9. 11/23/2018
Low PRF vs High PRF
A low PRF system has a lower implementation cost when compared to high PRF system
RF radio overall gain is lower for a low PRF system. A 12 MHz PRF system , for example, would reduce the receiver dynamic range by 7 dB when compared to a 60 MHz PRF system
The ADC would run at 12 MHz instead of 60 MHz in the above example and the entire digital processor would run at a lower clock reducing the power by a factor of 5 in CMOS
Easier acquisition with lower PRF due to a smaller sync matched filter size
Since energy per pulse is higher (7 dB in the above example), a non-coherent receiver would perform better
Better acquisition and tracking performance since a 60 MHz PRF system needs to integrate perfectly 5 pulses to perform equivalently to a 12 MHz PRF system
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

10. Proposed Frequency Plan
11/23/2018
Proposed Frequency Plan
Band No.
3 dB BW
(MHz)
Low Freq.
Center Freq.
High Freq. 1
494
3211
3458
3705 2
3952
4199 3
4446
4693 4
1482
Band No. 4
111
MHz
207
MHz 1 2 3 3
3.25
3.5
3.75 4
4.25
4.5
4.75 5
GHz
Note: This plan has almost double margin to 4.9 GHz as compared to 3.1 GHz
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

11. Frequency Plan Details
11/23/2018
Frequency Plan Details
New Band Plan
(in MHz)
XTAL 26 R 8
Fref
3.25 DF
494
F2C
3952
F2L
3705
F2H
4199
F1C
3458
F1L
3211
F1H
F3C
4446
F3L
F3H
4693
PRF1
61.75 N1 64 N2 56 N3 72
PRF2
30.875
128
112
144
PRF3
224
256
288
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

12. 11/23/2018
Proposed PRFs
A wide range of PRFs (total of 3) are supported which are compliant with the harmonic chip rate requirements
The base recommended PRF is MHz: it has an 8 dB peak power margin for a 500MHz BW
PRFs of MHz and 61.75MHz are also supported (margin > 4.5 dB)
The proposed PRFs can be easily generated from the center frequencies of the supported bands (next slide)
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

13. 11/23/2018
PRF Generation
All High frequency divisions are in powers of 2, while the low frequency divisions are only by 3 and 7
Center Freq.
(MHz)
PRF1
(MHz)
PRF2
(MHz)
PRF3
(MHz)
Harmonic Ratio
3952
61.75
30.875 64 2 2
3458
61.75
30.875
8x7 2 2
4446
61.75
30.875
8x3x3 2 2
Prime Factors: 7, 3
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

14. PLL Reference Diagram FX FComp F123,c ÷8 ÷ 7,8 or 9 FX (MHZ) R
11/23/2018
PLL Reference Diagram FX
FComp
Oscillator
Reference
Divider
(R)
XTAL
Phase Det.
F123,c
LPF
VCO
Divider, M ÷8
÷ 7,8 or 9
FX (MHZ) R
Fcomp (MHz)
(13,26)
(4,8)
0.8125
(9.6,19.2)
(24,48)
0.4
(12,24)
(6,12) 2
PRF
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

15. 11/23/2018
Band Plan / PRF Summary
Enough margin to 3.1GHz (111 MHz) and 4.9GHz (207 MHz) to meet FCC requirements and to coexist with WLAN ( avoids expensive sharp roll-off filtering)
Support of a wide range of XTALs (9.6,19.2,13,26,12,24)
Center frequencies and PRFs can be generated from a single PLL with first divisions in power of 2 and low frequency division by 3 or 7
Support of a wide range of PRFs. The proposed PRFs have a peak power margin of dB to accommodate implementation losses and take advantage of FCC rules
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

16. Acquisition Preamble Structure
11/23/2018
Acquisition Preamble Structure
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

17. BER of BPSK & ON-OFF Keying
11/23/2018
BER of BPSK & ON-OFF Keying
g (dB)
ON-OFF
BER
Opt.
Thres. 10
2.7e-2
2.72 11
1.3e-2
2.96 12
5.7e-3
3.24 13
1.94e-3
3.55 14
5.06e-4
3.91 15
9.47e-5
4.31 16
1.16e-5
4.77
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

18. 11/23/2018
BER Requirements
The requirement of PER < 1% for a 32 octets packet translates into a BER < 3.926e-5
EbN0 requirements for uncoded BPSK and ON-OFF keying systems:
g (BPSK) = 8.9dB
g (ON-OFF) = 15.45dB
EbN0 requirements for coded BPSK and ON-OFF keying systems (assuming a coding gain of 4dB and receiver implementation losses of 1.5 dB):
g (BPSK) = 6.4 dB
g (ON-OFF) = 13 dB
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

19. SNR Loss in Square Law Detectors
11/23/2018
SNR Loss in Square Law Detectors
PRF
32 MHz
EbN0
13 dB
Data Rate
2Mbps
100 kHz
EsNo
1 dB
-12 dB
SNRLoss
4dB
10 dB
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

20. BPSK: Detection & False Alarm Probabilities
11/23/2018
BPSK: Detection & False Alarm Probabilities
PRF = 16 MHz
AWGN Channel
2 dB margin to account for timing/frequency errors & other factors
PD = 95% & PF = 5%
Data Rate 2
Mbps 1
500
Kbps
250
125
62.5
32.25
EpN0(dB)
-2.5
-5.5
-8.5
-11.6
-14.6
-17.6
-20.6 Nc 32 L 4 12 36
112
448
256
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

21. BPSK: Detection & False Alarm Probabilities
11/23/2018
BPSK: Detection & False Alarm Probabilities
PRF = 16 MHz
Multipath Channel assuming we capture 25% of the energy
2 dB margin to account for timing/frequency errors & other factors
PD = 95% & PF = 5%
Data Rate 2
Mbps 1
500
Kbps
250
125
62.5
32.25
EpN0(dB)
-2.5
-5.5
-8.5
-11.6
-14.6
-17.6
-20.6 Nc 32 L 4 12 36
112
448
256
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

22. BPSK: Detection & False Alarm Probabilities
11/23/2018
BPSK: Detection & False Alarm Probabilities
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

23. BPSK: Detection & False Alarm Probabilities
11/23/2018
BPSK: Detection & False Alarm Probabilities
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

24. ON-OFF Detection & False Alarm Probabilities
11/23/2018
ON-OFF Detection & False Alarm Probabilities
PRF = 16 MHz
AWGN Channel
2 dB margin to account for timing/frequency errors & other factors
PD = 95% & PF = 5%
Data Rate 2
Mbps 1
500
Kbps
250
125
62.5
32.25
EpN0(dB) 4 -2 -5 -8
-11
-14 L 32 64 96
352
1280
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

25. Spreading Codes: Objectives
11/23/2018
Spreading Codes: Objectives
Design a set of sequences with good autocorrelation (ACF) and cross correlation (CCF) properties that support
Coherent receivers
Differentially coherent receivers
Noncoherent receivers
The sequence set should be as large as possible to support multiple piconets per frequency band and to mitigate co-channel interference (in-band interference)
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

26. Spreading Codes Desirable Characteristics
11/23/2018
Spreading Codes Desirable Characteristics
The autocorrelation function of a sequence can be characterized by the following parameters:
PAR of the PSD (back-off factor): a b PAR is desirable otherwise reduction in Tx power is required
Zero correlation zone (ZCZ) : for improved ranging, synchronization, channel estimation, and Pd vs Pf
Merit Factor (MF) of a binary sequence of length N: The MF measures the interference due to the sidelobe energies in the zone under interest (say 1μs)
Sequence length: this determines the coherent processing gain during acquisition ( a short spreading sequence  system is acquisition limited rather than PER limited)
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

27. Barker code 11 & m-sequence 31
11/23/2018
Barker code 11 & m-sequence 31
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

28. Freescale & ZCZ sequences
11/23/2018
Freescale & ZCZ sequences
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

29. Single Spreading Code System ?
11/23/2018
Single Spreading Code System ?
A single spreading code common to the preamble and frame body is not recommended as all good sequences have bad PSD which results in a large Tx power reduction (Back-off)
length
ZCZ width
SLL
Back-Off
Barker 11 1
1.2 dB
m-sequence 31 NA
4.5 dB
Freescale 24
2.1 dB
ZCZ 32 8
2.4 dB
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

30. Hierarchical Preamble code structure
11/23/2018
Hierarchical Preamble code structure
Let Z be the ZCZ sequence of length 3
Create hierarchical code using zero-correlation Walsh sequences 1,2,3 and 5
For ternary –Z corresponds to an inverted sequence
There are at least 32 ZCZ, this gives 128 SOPs
Seq1 Z
Seq2 -Z
Seq3
Seq4
Seq5
Seq6
Seq7
Seq8
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

31. modulation 11/23/2018 Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.

32. Modulation Spreading via random scrambling
11/23/2018
Modulation
Spreading via random scrambling
Use a single 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)
Ismail Lakkis & Saeid Safavi
Wideband Access, Inc.