1. Submission Title: Potential 802.15.4g issues Date Submitted: May 2014
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Potential g issues
Date Submitted: May 2014
Source:
Frederik Beer, Joerg Robert, Friedrich-Alexander University (FAU) / Fraunhofer IIS, Am Wolfsmantel 33, Erlangen, Germany
Abstract: Three ambiguities in the 4g amendment
Purpose: Fueling discussion in SC-M
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.
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Frederik Beer, Joerg Robert

2. Frederik Beer, Joerg Robert May, 2014
Potential g issues
Frederik Beer, Joerg Robert
May, 2014
Frederik Beer, Joerg Robert

3. Outline: Handling of data whitening with enabled FEC
May 2014
Outline:
Handling of data whitening with enabled FEC
Modulator structure for data whitening with enabled FEC
Channel numbering table
Frederik Beer, Jörg Robert

4. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
January 2014
1. DW with FEC (1):
4g has a new PHR structure where one bit is used for signalling the usage of DW
Additionally 4g allows for usage of a NRNS convolutional FEC
Both features, DW and FEC, can be used simultaniously
Frederik Beer, Jörg Robert
<author>, <company>

5. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
1. DW with FEC (2):
The reference modulator diagramm (Fig. 117) states that the FEC block comes before the DW block
Thus on receiver side, de-scrambling has be to done before FEC decoding
However the DW bit in the PHR is buried within the FEC protected datastream
Due to the traceback length of a Viterbi decoder bits of the PSDU have to be used in order to decoder the DW bit, BUT no knowledge about the PSDU bits (DW enabled or not?) is available at that point
Frederik Beer, Jörg Robert
<author>, <company>

6. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
1. DW with FEC (3):
PHR bit
PSDU bit
Traceback length of the Viterbi decoder
(5x constraint length)
Bit # 1 2 3 4 15 16 17 18 19 20 21 22 23 24 25 26
DW bit
Frederik Beer, Jörg Robert
<author>, <company>

7. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
1. DW with FEC (4):
Possible solutions:
DW is mandatory
DW over the whole PHR+PSDU
Run two decoders in parallel
Reverse the order of FEC and DW block in the modulator
Use only systematic codes
Leave it as it is, forcing everyone to reduce traceback length of decoder (reduced performance) …
Note: This issue affects ALL features which are signalled in the PHR and affects the bits in the PSDU!
Frederik Beer, Jörg Robert
<author>, <company>

8. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
2. DW of PHR and PSDU (1):
4g specifies that only the bits belonging to the PSDU shall be processed by the DW block
PSDU and PHR are fed into the FEC block as a single continous stream (subclause and Fig. 120)
After the FEC block a clear seperation into PSDU related bits and PHR related bits is impossible with current structure
Frederik Beer, Jörg Robert
<author>, <company>

9. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
2. DW of PHR and PSDU (2):
Possible solutions:
Reverse the order of FEC and DW block in the modulator
Use termination sequences between PHR and PSDU (as defined in Fig. 148 (4g) and Fig. 167 (4k)
Frederik Beer, Jörg Robert
<author>, <company>

10. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
3. Channelpage (1):
4g defines a wide range of frequency bands, channels and modulation types
ChanCenterFreq0 does not show any particular pattern:
Frederik Beer, Jörg Robert
<author>, <company>

11. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
3. Channelpage (2):
At MHz band and MR-FSK OM #1 the last channel would be exactly at the frequency band boundary:
Frederik Beer, Jörg Robert
<author>, <company>

12. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
May 2014
General Suggestion:
Encourage task groups to install a verification & validation (V&V) process
Widely used in other standardization bodies
Currently V&V procedure as suggestion in the 4q group
Would be additional to the checks and proofreading during balloting
Frederik Beer, Jörg Robert
<author>, <company>