1. Submission Title: [Example UWB Tx Data]
November 2006
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Example UWB Tx Data]
Date Submitted: [15−November−2006]
Source: [Michael Mc Laughlin] Company [Decawave Ltd.]
Address [25 Meadowfield, Sandyford, Dublin 18, Ireland]
Voice:[+353− ], FAX: [What’s a FAX?], E−Mail:
Re: [ a.]
Abstract: [Examines anomalies thrown up by trying to modulate some example data with the UWB radio]
Purpose: [To promote discussion in a.]
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
Mc Laughlin, Decawave

2. Example UWB transmit Annex
November 2006
Example UWB transmit Annex
Matlab Function to encode example UWB data according to Draft 5
Example case is a mandatory one:
850Mbps, mean PRF 15.6MHz , 500MHz wide Channel
code index 6 for channel 3
Followed the instructions unless there seemed to be an error
Came across places which need
Fixes for errors
Clarifications
Mc Laughlin, Decawave

3. Input and Output UWB welcomes IEEE Output pulses
November 2006
Input and Output
Output pulses
Burst Start Chip
Burst
−+++
−−−−−−−−−−++−−−−
256
−+−+++++
−−−−−−++++−−−−−−
−−−−+−−−+−−−−−−−
320
++−−++−− 80
+−+−+−+−−−−−−−++
112
−−−−−−++++++−+++
−−−−+−−−−−++−−−−
++−−++++−+−+++++
+−+−−−++++−−−−++ 48
−−++−+++−+++−+++
+−++−−++−−++−−++
336
+−+−+−+−+−+−+−−+
368
−−−−−−−−−−−−+−++
−−−−−−−−−−+++−−−
−−−−−−−−+−−+−−−−
−−−−−−++−++−−−−−
−−−−+−++−+−−−−−−
++−−−+−−−
272
etc…
PSDU input data from MAC
UWB welcomes IEEE
Note: No CRC
Intermediate data checkpoints
Phy Header
Number information bits, I = 136.
PSDU Bits
RS Encoded Bits
Convolutional Input Bits
G0 bits
G1 bits
Scrambler Out
Mc Laughlin, Decawave

4. November 2006
Convolutional Coding
In 6.8a.9.2, the convolutional encoder must be initialised to [0 0];
CID 422
In 6.8a.9.2, there will be a performance loss unless the first systematic and parity bits are transmitted
I can’t find any text which says that tail bits are added. I believe we need two.
Mc Laughlin, Decawave

5. RS Encoder 6.8a.9.1, Page 76, Line 14 should be k=0 to 54 and not
November 2006
RS Encoder
6.8a.9.1, Page 76, Line 14 should be
k=0 to 54
and not
k=1:54
CID 115
Confirmed with Ismail that Eqn 6.8a.9.1, Page 76, Line 46 should be:
U(x) = x8D(x) + P(x)
U(x) = D(x) + x8P(x)
CID 453
Mc Laughlin, Decawave

6. November 2006
Time Hopping
In section 6.8a.8.2 What happens to the h(k) if there are not enough bits in Ncpb to make a new burst position, i .e. Ncpb<m. Does it re-use the older ones? I think it implies yes. Should say this explicitly e.g. we say:
“Note that for Ncpb < m, the LFSR is clocked Ncpb times, not m times.”
CID 422
In section 6.8a.8.2 page 74, m= log2(#Hopping Bursts), but table 39a uses Nhop so this would be much clearer if it said m= log2(Nhop)
Already fixed
Mc Laughlin, Decawave

7. Consistent Terminology
November 2006
Consistent Terminology
Figures 27i and 27k use c0 and c1 for the convolutional coder output, everywhere else uses g0, g1. Should make this consistent.
CID 81
Tchip is used in Fig27c , Tc other places
Already fixed
Reference to dump bits in 6.8a.9.1 Reed-Solomon encoder. Should this be dummy bits?
CID 422
Mc Laughlin, Decawave

8. November 2006
Scrambler
In Table 39h it’s confusing that the scrambler initialiser and the scrambler output are in opposite order
Flip initial code order and Fig 27i
CID 222
In Table 39h there are 16 bits in the Initial state table but they are assigned to 15 things (s-1 to s-15)
Initial code uses first 15 elements of preamble code after 0s removed and -1s changed to 0
CID 219
Because the scrambler initialiser is nearly all ones, the first 4 hopping positions in a frame will always be zero. Don’t know if this is really bad, but don’t like it
Because the scrambler initialiser is nearly all ones, the first 6 symbols are heavily DC biased. Don’t like this one at all. TG4a packets can be very short. This can be a significant part of them
Mc Laughlin, Decawave

9. Conclusions Some errors found Some editorial changes required
November 2006
Conclusions
Some errors found
Some editorial changes required
We have sponsor comments to hang each of these on.
Mc Laughlin, Decawave