1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2005
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [TG4a Frequency Band Proposal]
Date Submitted: [May 2004]
Source: [Matt Welborn]
Company [Freescale Semiconductor, Inc]
Address [8133 Leesburg Pike, Vienna VA 22182]
Voice:[ ], FAX: [], freescale.com]
Re: [Response to Call for Proposals]
Abstract: [This document describes a frequency band proposal for the TG4a baseline draft standard.]
Purpose: [Proposal Presentation for the IEEE a standard.]
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
Welborn (Freescale)
<author>, <company>

2. May 2005
Objectives
Propose a frequency band plan in accordance with the TG4a baseline draft standard merger document
Summary of requirements for band plan, omitting N/A bullets
Sub-banding:
Center of three bands is mandatory, Other two optional
Wider bandwidth (1.5 GHz+) concentric with center band is optional
CDMA within frequency bands
Harmonic chip rate – integer relationship between center frequency and chip rate
Mandatory
~500 center band (AM of is 3.975, GM of is 3.877)
Center band frequency is TBD, but must be in [3.85 to 4.05]
Optional
2 additional 500 MHz bands for FDM – center frequencies TBD
Wideband concentric with center specified above
Sub-GHz band …
Add specific optional band > 6 GHz with guaranteed >1.5GHz BW
Support mode for higher data rates (few to 10 Mbps)
Other issues
Multiple (2-few) PRF in band
Welborn (Freescale)

3. Advantages Meets requirements of TG4a baseline draft
May 2005
Advantages
Meets requirements of TG4a baseline draft
Uses non-uniform bandwidths for mandatory and two optional narrow bands
Allows same pass-band pulse shape to be used in each band (simplifies pulse generation)
Provides more uniform performance for each of three narrow bands
PRF would also scale with changing center frequency to allow fixed (integer) relationship between center frequency, BW and chip rate
All frequencies (chip rates, pulse burst rates, center frequencies) can be integer multiple of a 13 MHz reference
Welborn (Freescale)

4. Signal Design Objectives
May 2005
Signal Design Objectives
Technical Objectives:
Support for low-complexity, non-coherent receiver architectures (energy detect and energy collector)
Support for higher-complexity coherent architectures
Support for ranging for both architectures (TOA and TDOA)
Support for data rates as high as 7 to 14 Mbps
Welborn (Freescale)

5. Frequency Plan Band No. Bandwidth (MHz) Low Freq. Center Freq.
May 2005
Frequency Plan
Band No.
Bandwidth
(MHz)
Low Freq.
Center Freq.
High Freq.
1(optional)
500+
3164
3432
3700
2 (Mandatory)
3702
3978
4254
3 (optional)
4241
4524
4807
4 (optional)
1500+
3149
4806
Band No. 4 1 2 3 3
3.25
3.5
3.75 4
4.25
4.5
4.75 5
GHz
Welborn (Freescale)

6. Higher Band Frequency Plan
May 2005
Higher Band Frequency Plan
Band No.
Bandwidth
(MHz)
Low Freq.
Center Freq.
High Freq.
5(optional)
1000+
6387
6864
7341
6 (optional)
7404
7956
8509
7 (optional)
8420
9048
9676
8 (optional)
~3000
6298
9615
Band No. 8 5 6 7 6
6.5 7
7.5 8
8.5 9
9.5 10
GHz
Welborn (Freescale)

7. Main Features of proposed system
May 2005
Main Features of proposed system
Proposal main features:
Impulse-radio based (pulse-shape independent)
Common synchronisation / ranging preamble signaling for different classes of nodes / type of receivers (coherent / noncoherent)
Band Plan based on multiple 500+ MHz bands (center band mandatory) and optional wider bandwidth (~1.5 GHz+) concentric with center band
Robustness against SOP interference
Robustness against other in-band interference
Scalability to trade-off complexity/performance
Welborn (Freescale)

8. Details of proposed system
May 2005
Details of proposed system
Proposed waveform is similar to others proposed by Samsung, Mitsubishi, Time Domain and I2R
Should make it easier to get group support
Data symbols are transmitted using short sequences of pulses with “silent” periods
Allows coherent reception and also “energy collector” or “energy detector” architecture as well
Should support implementing low-power, low-complexity devices and still provide good performance in multipath
Welborn (Freescale)

9. Signals already proposed by Others (Mitsubishi, TDC, I2R, etc)
May 2005
Signals already proposed by Others (Mitsubishi, TDC, I2R, etc)
One Bit
Optionally
Empty
Always Empty
Always Empty 32 32 32
Next potential active time
32 chip sequence
The Other Bit
Optionally
Empty
Always Empty
Always Empty 32 32 32
Only 160 ns of channel multipath tolerance in this case.
Next potential active time
32 chip times
We transmit one or the other of these patterns to carry data.
Welborn (Freescale)

10. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2005
One possible mapping of pulses to bits:
Use 31-chip Codes
Symbol
Cyclic shift to right by n chips, n=
31-Chip value 00 01 8 11 16 10 24
Can support both coherent and non-coherent pulse compression
Add 33 zero chips to get baseline mode for non-coherent receivers
However, these codes have poor spectral properties (see following slides)
Welborn (Freescale)
<author>, <company>

11. Signal structure using a 31-chip Burst Sequence
May 2005
Signal structure using a 31-chip Burst Sequence
Hypothetical 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
Ts = 140 ns
Tm = ~290 ns
Based on same 31-chip sequences proposed by Francois Chin of I2R at ~4.5 ns Tc spacing
These codes need to be further analyzed to make sure spectral properties are acceptable
Welborn (Freescale)

12. May 2005
PSD plots for Proposed 31-chip codes – These codes cost 5 dB or more in Tx power 2 3 4 5 6
x 10 9
-70
-60
-50
-40
Code number 1 Back-off = dB
Code number 2 Back-off = dB
Code number 3 Back-off = dB
Code number 4 Back-off = dB
Code number 5 Back-off = dB
Code number 6 Back-off = dB
Welborn (Freescale)

13. The Impact of a Poor Spectrum
May 2005
The Impact of a Poor Spectrum
As we see, the PSD using the 31-chip codes results in about 5 dB Tx power reduction
Result is reduced range and/or robustness
An alternative is to consider similar length codes that have better spectral properties
One example would be length-24 ternary codes with two “zeros” per code
Codes exist that could provide only a 2 dB penalty on Tx power (see next page)
Other codes exist, including “hierarchical codes”, analysis is ongoing
Code Set Number
L=24 Codes 1
-1, 0, 1, -1, -1, -1, 1, 1, 0, 1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1 2
-1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 0, -1, 0, 1, 1 3
-1, 1, -1, -1, 1, -1, -1, 1, -1 , 0 -1, 0, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, -1, -1 4
0, -1, -1, -1, -1, -1, -1, 1, 1, 0, -1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1 5
-1, 1, -1, 1, 1, -1, 1, 0, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, 1, -1, -1, -1, 0, -1 6
0, -1, -1, 0, 1, -1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1
Welborn (Freescale)

14. May 2005
PSD plots for Proposed 24-chip codes Multiple codes are available with only ~2 dB backoff 2 3 4 5 6
x 10 9
-70
-60
-50
-40
24-bit Code number 1 Back-off = dB
24-bit Code number 2 Back-off = dB
24-bit Code number 3 Back-off = dB
24-bit Code number 4 Back-off = dB
24-bit Code number 5 Back-off = dB
24-bit Code number 6 Back-off = dB
Welborn (Freescale)

15. PSD plots for Barker 11 & 13 codes (for reference)
May 2005
PSD plots for Barker 11 & 13 codes (for reference)
Barker Back-off = dB
Barker Back-off = dB
-35
-35
-40
-40
-45
-45
-50
-50
-55
-55
-60
-60
-65
-65
-70 2 3 4 5 6
-70 2 3 4 5 6
x 10 9
x 10 9
Welborn (Freescale)

16. Expanded View of 24-chip Burst Sequence
May 2005
Expanded View of 24-chip Burst Sequence
Similar signal using 24-pulse sequence
Can use coherent or non-coherent receiver
Can use PPM/OOK by sending pulse burst in
Either first or second bit location
Ts = 109 ns
Tm = ~218 ns
One BPPM symbol
24-chip codes sent at 221 MHz
rate (~4.5 ns per pulse)
The “burst” rate is an average
2.3 MHz for the 2-PPM mode
Welborn (Freescale)

17. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2005
Proposed System Parameters (Mandatory Center Band)
Bandwidth*
552 MHz [= dB * 1.25 for excess BW]
Pulse Burst Frequency (symbol rate)
2.3 MHz [= 1/(2*Tm)]
# Chip / symbol (Code length)
24-chip sequence + 24-chip “zero” padding (silence)
“Chip rate” inside burst
221 MHz (= Fcenter / 6)
Channel coding
Convolutional code K = 4, r=3/4 (low complexity)
Symbol Rate
Same as Pulse burst frequency above
Mandatory bit rate
3/4 x 2.3 MSymbols/s = 1.73 Mbps
Optional bit rates (others possible)
(For “coherent-only” higher rate modes, no zero padding is used so the symbol rate is 1/Tm)
3/4 x 1.15 MSps = 0.86 Mbps (non-coherent)
3/4 x 4.6 MSps = 3.45 Mbps (non-coherent )
3/4 x 9.2 MSps = 6.9 Mbps (coherent)
3/4 x 18.4 MSps = 13.8 Mbps (coherent)
Lower bit rate scalability
Symbol Repetition
Modulation
{+1,-1} bipolar and PPM/OOK of ternary pulse train
Total # simultaneous piconets supported
6 per FDM band
Multiple access for piconets
CDM (fixed code) + FDM (fixed band)
Bandwidth: Optional bands #1 & 3 are slightly different BW and frequency as noted on previous slides
Wide band #4 uses narrower pulses to achieve higher bandwidth
Welborn (Freescale)
<author>, <company>

18. May 2005
RFD and FFD
Proposal is to allow RFD to have only non-coherent receiver
Will have reduced range, but much lower complexity
RFD can do TOA ranging and will need FFD to do TDOA ranging
FFD can form and coordinate piconet for low cost/low complexity RFD radios
Coherent Receiver = FFD
RFD can use simple non-coherent receiver for OOK or PPM
FFD
Welborn (Freescale)

19. May 2005
Ranging
Can support ranging for both coherent and non-coherent receivers
Coherent receivers act as “Full function devices” (FFD) and non-coherent receivers act as “Reduced function devices” (RFD)
RFDs can do TOA ranging at short distance in less severe channels (same room?)
RFDs can participate in a piconet with FFDs that can serve as “reference” nodes to do TDOA ranging
Welborn (Freescale)

20. TOA Ranging for both FFD and RFD
May 2005
TOA Ranging for both FFD and RFD
Mobile (xm,ym)
Anchor 2 (xA2,yA2)
Anchor 3 (xA3,yA3)
Anchor 1 (xA1,yA1)
Positioning from TOA
3 anchors with known positions (at least) are required to retrieve a 2D-position from 3 TOAs
Measurements
Estimated Position
Specific Positioning Algorithms
Welborn (Freescale)

21. TDOA Ranging Requires FFDs to Act as “Reference Nodes”
May 2005
TDOA Ranging Requires FFDs to Act as “Reference Nodes”
reference node = FFD
SOI = RFD – only needs to transmit signal when TDOA ranging
FFD
FFD
Key:
Sync Pulse
Location Pulse
TDOA backhaul
Controller:
Can be wired or wireless connection to FFDs
Needs protocol to allow synchronizing clocks
Mode 2 - Active
Welborn (Freescale)

22. May 2005
Proposed Signal uses 24-chip pulse sequence, similar to original “Chaotic” noise signals and can support Non-coherent Receivers
Original signal proposed by
Samsung for non-coherent receiver
Ts = 100 ns
Tm = 400 ns
Similar 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
Ts = 109 ns
Tm = ~218 ns
Welborn (Freescale)