1. 7-May-2007
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [DecaWave Proposal for TG3c Alternative PHY]
Date Submitted: [2007-May-7th]
Source: [Brian Gaffney, Michael Mc Laughlin] Company [DecaWave]
Address [25 Meadowfield, Sandyford, Dublin 18, Ireland]
Voice:[ ], FAX: [none],
Re: [Response to Call for Proposals c-tg3c-call-proposals.doc]
Abstract: [Alternative PHY Proposal for TG3c]
Purpose: [To assist TG3c in selecting a mm Wave PHY]
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
Gaffney, Mc Laughlin, DecaWave

2. 7-May-2007
DecaWave 3c Proposal
Gaffney, Mc Laughlin, DecaWave

3. Proposal Outline Single Carrier system.
7-May-2007
Proposal Outline
Single Carrier system.
Adaptive Phased Antenna Array to boost SNR at receiver and provide spatial multiple access
Low complexity
Multi-national regulatory compliance.
Gaffney, Mc Laughlin, DecaWave

4. Proposed Band Plan U.S. Japan 1.6Ghz 57 59 64 66 f(Ghz) ~2.2Ghz
7-May-2007
Proposed Band Plan
U.S.
Japan
1.6Ghz 57 59 64 66
f(Ghz)
~2.2Ghz
Gaffney, Mc Laughlin, DecaWave

5. Modulation Scheme 8-QAM Allows for Non-Coherent reception
7-May-2007
Modulation Scheme
8-QAM
Used in the V.29 modem standard due to resilience to phase noise.
Higher bandwidth efficiency than QPSK.
More resilient to phase noise and power amplifier problems than higher order constellations (16-QAM).
Allows for Non-Coherent reception
Only two levels Q I R1 R0
Gaffney, Mc Laughlin, DecaWave

6. Error Correction Coding
7-May-2007
Error Correction Coding
Outer systematic Reed Solomon block code.
Inner systematic Convolutional code.
Constraint length K = 5 and rate 1/3.
One information bit in produces 3 bits out (the information bit and two parity bits) which are mapped to a symbol in the 8-QAM constellation.
Systematic to allow for Non-Coherent Reception for low complexity receivers
File Transfer and Kiosk usage scenarios
Gaffney, Mc Laughlin, DecaWave

7. 7-May-2007
Outer Reed Solomon
The systematic Reed Solomon code is over the Galois field GF(26) and is given as RS(63,55).
Input of 55 symbols creates 8 parity symbols for a rate 0.87 code.
Systematic gives the option of ignoring the parity symbols in low complexity receivers.
Used in the a standard.
Interleaved output before input to inner code improves performance by separating burst errors at the receiver.
Gaffney, Mc Laughlin, DecaWave

8. Convolutional Code Generator Polynomial: g1=208, g2 = 278, g3 =328. +
7-May-2007
Convolutional Code + +
Generator Polynomial: g1=208, g2 = 278, g3 =328.
Gaffney, Mc Laughlin, DecaWave

9. Convolutional Code With K=5, there are only 16 possible states.
7-May-2007
Convolutional Code
With K=5, there are only 16 possible states.
8 branch metrics need to be calculated per symbol
Other coding techniques, which achieve better performance, such as LDPC codes were investigated, but the convolutional code was chosen because it is easier to implement at the high data rates of interest.
Gaffney, Mc Laughlin, DecaWave

10. 7-May-2007
Convolutional Code
Systematic code gives the option of ignoring the parity bits
Important for Non-Coherent receiver. To be covered later.
However, systematic codes are known to perform worse than non-systematic.
We have developed the previous code in conjunction with a bit to symbol mapping which approaches the performance of a Gray coded constellation with maximum free distance non-systematic code.
Gaffney, Mc Laughlin, DecaWave

11. 8-QAM Constellation 001 100 101 000 010 111 110 011 7-May-2007
Gaffney, Mc Laughlin, DecaWave

12. Our 8-QAM versus Gray Coded
7-May-2007
Our 8-QAM versus Gray Coded
Gaffney, Mc Laughlin, DecaWave

13. Data Modes Four Data Modes: Base mode 1.4Gbps
7-May-2007
Data Modes
Four Data Modes:
Base mode 1.4Gbps
High data rate mode 2.8Gbps
Very High data rate mode 4.2Gbps
Low rate (67Mbps) back channel mode obtained by sending a direct sequence code
Gaffney, Mc Laughlin, DecaWave

14. Base Mode – 1.4Gbps Base mode Inner and Outer coding
7-May-2007
Base Mode – 1.4Gbps
Base mode
One bit per symbol.
Pulse Repetition Frequency (PRF) = Bandwidth (B)
Data rate = 0.87*B Gbs
Inner and Outer coding
Interleave RS output
Spatial multiple access
Gaffney, Mc Laughlin, DecaWave

15. 7-May-2007
Base Mode – 1.4Gbps
Gaffney, Mc Laughlin, DecaWave

16. High Data Rate Mode – 2.8Gbps
7-May-2007
High Data Rate Mode – 2.8Gbps
High Data Rate mode
Two bits per symbol
Punctured Base mode
PRF = B
Interleave RS output
Data rate = 2*0.87*B Gbs
Not transmitted
From convolutional coder s1 s2 s3 s4 s5 s6
Gaffney, Mc Laughlin, DecaWave

17. High Data Rate Mode – 2.8Gbps
7-May-2007
High Data Rate Mode – 2.8Gbps
Gaffney, Mc Laughlin, DecaWave

18. Very High Data Rate Mode – 4.2Gbps
7-May-2007
Very High Data Rate Mode – 4.2Gbps
Very High Data Rate mode
No convolutional code
Reed Solomon RS(63,55)
Interleave RS output
Data rate = 3*0.87*B Gbs
Gaffney, Mc Laughlin, DecaWave

19. Very High Data Rate Mode – 4.2Gbps

20. Low Data Rate Mode – 67Mbps
7-May-2007
Low Data Rate Mode – 67Mbps
Low data rate back channel mode.
Length 21 Ipatov ternary sequence.
+00−++−0+0+−+++++−−0−
Golay Merit Factor of 5.3
Gives the option of 67Mbs (base mode) or 133Mbs (high data mode) which is more resistant to errors
Gaffney, Mc Laughlin, DecaWave

21. Non Coherent Reception
7-May-2007
Non Coherent Reception
The Non Coherent receiver is ideal for File Transfer or the Kiosk modes
The systematic bit decides which “ring” the transmitted symbol is on. Therefore, by using a simple energy detector receiver we can decode the systematic bit from any base mode signal.
The Outer Reed Solomon code then gives some optional error correcting capabilities
Gaffney, Mc Laughlin, DecaWave

22. Non Coherent Reception
7-May-2007
Non Coherent Reception
to RS decoder
from antenna
LPF
exp(j2πfct)
Gaffney, Mc Laughlin, DecaWave

23. Non Coherent Reception
7-May-2007
Non Coherent Reception
Used with a directional antenna, we can achieve a data rate of 0.87*B Gbs at short range
Enables a very low cost implementation
Ideal for integration into media players, phones, cameras etc.
Gaffney, Mc Laughlin, DecaWave

24. Non Coherent Reception
7-May-2007
Non Coherent Reception
Gaffney, Mc Laughlin, DecaWave

25. 7-May-2007
Phased Antenna Array
We propose using a phased antenna array to boost the signal to noise ratio at the receiver input and provide spatial multiple access.
The phased antenna array can adapt to any direction of arrival (assuming omni directional elements)
The phased antenna array offers a low complexity solution
Gaffney, Mc Laughlin, DecaWave

26. 7-May-2007
Phased Antenna Array +
Gaffney, Mc Laughlin, DecaWave

27. 7-May-2007
Phased Antenna Array
For omni directional antenna elements, the phased antenna array can achieve a high gain in any given direction. For example, ten elements (uniform linear array) can give a gain of 10dBi
To achieve higher gains, directive elements need to be applied which require some physical alignment of Tx and Rx
The non-coherent mode could have a single highly directive element and assume the user will align the Tx and Rx
Gaffney, Mc Laughlin, DecaWave

28. 7-May-2007
Hidden Node Problems
Major problem with directive antenna systems is finding Nodes.
To combat this problem, we propose using a single element mode.
For omni-directional antenna elements, we can now “see” in every direction.
For directive antenna elements, we can only “see” in the direction we can adapt in.
Gaffney, Mc Laughlin, DecaWave

29. 7-May-2007
Hidden Node Problems
However, the path loss is so high at 60Ghz, a very weak signal is received when we are not using the antenna array gain
The Solution:
Compensate for the lack of antenna array gain at Tx and Rx by spreading the signal to obtain an equal or higher processing gain
Much lower data rate, but not so important at the start of communication
Gaffney, Mc Laughlin, DecaWave

30. Ternary Spreading Sequence
7-May-2007
Ternary Spreading Sequence
Ipatov Sequence
Perfect Periodic Autocorrelation properties.
Allows for accurate channel estimation for Channel Matched Filtering (CMF) and Antenna Array adaptation.
Used in a
For example, a length 183 sequence is equivalent to an antenna array gain of approximately 22.2 dBi
Many such sequences allows separate piconets to co-exist
Example length 183 Ipatov Sequence:
+−−−+0+−−−−−++−− −−++0+−+−+−+−−00−−+−+−++−−++−−+−0−−−++−−0−++−0−−+++−+++−−+−+−−+−+++++0−−++−−++−+−−− −0−−−−−+−++−−0++++−+−−−−+++−+−+−−++−++−+0−++++−+−++++−++− −+−−+
Gaffney, Mc Laughlin, DecaWave

31. Ternary Spreading Sequence
7-May-2007
Ternary Spreading Sequence
Periodic Auto Correlation of Length 183 Ipatov Sequence
Gaffney, Mc Laughlin, DecaWave

32. Ternary Spreading Sequence
7-May-2007
Ternary Spreading Sequence
With the perfect autocorrelation we can obtain an excellent estimate of the channel for the Channel Matched Filter (CMF)
Send 16 times before each packet
However, inter symbol interference (ISI) due to multipath in the channels without a dominant single path is not combated by the CMF
Instead of equalization, we want to use the antenna to point in a direction which gives a useable channel
Gaffney, Mc Laughlin, DecaWave

33. Interference & susceptibility
7-May-2007
Interference & susceptibility
All out of band interference filtered out.
Adjacent channel interference is filtered out.
However, power amplifier backoff will affect this and will be addressed fully at future meetings.
Co-channel interference is avoided by spatial multiple access.
Narrowband interference rejection with digital notch filter
Tones can be detected at the A/D output.
A simple notch filter either at the input or output of the matched filter can then remove this completely with no loss in performance (if notch is narrow enough).
Gaffney, Mc Laughlin, DecaWave

34. Link Budget (LOS) Parameter Low Base High Rate Very High Rate
7-May-2007
Parameter
Low
Base
High Rate
Very High Rate
Non Coherent
PHY-SAP Payload Bit Rate (Rb)
67Mb/s
1.4Gb/s
2.8Gb/s
4.2Gb/s
Average Transmit Power
10dBm
Transmit Antenna Gain
10dBi
Center frequency (fc)
60GHz
Path loss at 1 meter
68dB
Receive Antenna Gain
0dBi
Average noise power per bit
-69.3dBm
-82.5dBm
-79.5dBm
-77.7dBm
Noise Figure
8dB
-74.5dBm
-71.5dBm
-69.7dBm
Minimum Eb/N0 for AWGN channel
2.75dB
5.75dB
9.5dB
21dB
Shadowing link margin
1dB
Implementation Loss
2dB
Tolerable path loss
34.0dB
27.8dB
19.2dB
12.5dB
Maximum operating range (d = 10 PL/10n,n=2)
50m
24.4m
11.2m
9.1m
4.2m
Gaffney, Mc Laughlin, DecaWave

35. Link Budget (NLOS) Parameter Base High Rate 7-May-2007
PHY-SAP Payload Bit Rate (Rb)
1.4Gb/s
2.8Gb/s
Average Transmit Power
10dBm
Transmit Antenna Gain
13dBi
Center frequency (fc)
60GHz
Path loss at 1 meter
68dB
Receive Antenna Gain
Average noise power per bit
-82.5dBm
-79.5dBm
Noise Figure
8dB
-74.5dBm
-71.5dBm
Minimum Eb/N0 for AWGN channel
5.75dB
9.5dB
Shadowing link margin
5dB
Implementation Loss
2dB
Tolerable path loss
29.75dB
23.05dB
Maximum operating range (d = 10 PL/10n,n=2.5)
15.5m
8.4m
Gaffney, Mc Laughlin, DecaWave

36. Link Budget Summary Bit Rate Channel Model Range for 10-2 PER
7-May-2007
Link Budget Summary
Bit Rate
Channel Model
Range for 10-2 PER
67Mbps
LOS
50m
1.4Gbps
24.4m
2.8Gbps
11.2m
4.2Gbps
7.7m
NLOS
15.5m
8.4m
Gaffney, Mc Laughlin, DecaWave

37. 7-May-2007
Base Mode CM 1.3
Gaffney, Mc Laughlin, DecaWave

38. 7-May-2007
Base Mode CM 2.3 (NLOS)
Gaffney, Mc Laughlin, DecaWave

39. 7-May-2007
Base Mode CM 3.1
Gaffney, Mc Laughlin, DecaWave

40. 7-May-2007
High Data Rate CM 1.3
Gaffney, Mc Laughlin, DecaWave

41. Performance Summary Bit Rate Channel Model Range for 10-2 PER
7-May-2007
Performance Summary
Bit Rate
Channel Model
Range for 10-2 PER
1.4Gbps
CM 1.3
33m
CM 2.3
10.5m
CM 3.1
23.5m
2.8Gbps
14.8m
Gaffney, Mc Laughlin, DecaWave

42. Summary of our proposal
7-May-2007
Summary of our proposal
8-QAM modulation scheme
4 Data rates
Base mode of 1.4Gps obtained with outer RS (rate 0.87) and inner convolutional (rate 1/3) coding
High data rate mode of 2.8Gps obtained by puncturing base mode signal
Very high data rate mode of 4.2Gps obtained by using only RS code
Lower rate for back channel using Direct Sequence code
Systematic code developed specifically for the 8-QAM constellation which enables a Non-coherent receiver architecture
Node discovery and channel adaptation with omni directional antenna mode with spreading gain from long ternary sequence
Gaffney, Mc Laughlin, DecaWave

43. Advantages Low complexity solution
7-May-2007
Advantages
Low complexity solution
Constellation resilient to RF impairments
Simple Non-coherent mode
Ideal for low cost receiver e.g. for media player
Single carrier
potential common signalling mode operation
More resistant to multipath
Ternary sequences and omni-directional antenna mode allow easy node discovery
Multi-national regulatory compliance
Gaffney, Mc Laughlin, DecaWave