Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Frederik Beer, Joerg Robert Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title:Potential 802.15.4g issues Date Submitted: May 2014 • Source: • Frederik Beer, Joerg Robert, Friedrich-Alexander University (FAU) / Fraunhofer IIS, Am Wolfsmantel 33, 91058 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 P802.15. 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 P802.15.

2. Frederik Beer, Joerg Robert May, 2014 Frederik Beer, Joerg Robert Potential 802.15.4g issues

3. Outline: Handling of data whitening with enabled FEC Modulator structurefordatawhiteningwithenabled FEC Channel numberingtable Frederik Beer, Jörg Robert

4. Frederik Beer, Jörg Robert 1. DW with FEC (1): • 4g has a new PHR structurewhereonebitisusedforsignallingtheusageof DW • Additionally 4g allowsforusageof a NRNS convolutional FEC • Bothfeatures, DW and FEC, canbeusedsimultaniously

5. Frederik Beer, Jörg Robert 1. DW with FEC (2): • The referencemodulatordiagramm (Fig. 117) statesthatthe FEC block comesbeforethe DW block • Thus on receiver side, de-scrambling has be to done before FEC decoding • Howeverthe DW bit in the PHR isburiedwithinthe FEC protecteddatastream • Due tothetracebacklengthof a Viterbidecoderbitsofthe PSDU havetobeused in ordertodecoderthe DW bit, BUT noknowledgeaboutthe PSDU bits (DW enabledor not?) isavailable at thatpoint

6. Frederik Beer, Jörg Robert 1. DW with FEC (3): PHR bit PSDU bit Traceback length of the Viterbi decoder (5x constraint length) Bit # 0 1 2 3 4 15 16 17 18 19 20 21 22 23 24 25 26 DW bit

7. Frederik Beer, Jörg Robert 1. DW with FEC (4): • Possiblesolutions: • DW ismandatory • DW over the whole PHR+PSDU • Run two decoders in parallel • Reverse theorderof FEC and DW block in themodulator • Useonlysystematiccodes • Leaveitasitis, forcingeveryonetoreducetracebacklengthofdecoder (reducedperformance) • … • Note: This issue affects ALL features which are signalled in the PHR and affects the bits in the PSDU!

8. Frederik Beer, Jörg Robert 2. DW of PHR and PSDU (1): • 4g specifiesthatonlythebitsbelongingtothe PSDU shallbeprocessedbythe DW block • PSDU and PHR arefedintothe FEC block as a singlecontinousstream (subclause 18.1.2.1 and Fig. 120) • After the FEC block a clearseperationinto PSDU relatedbitsand PHR relatedbitsisimpossiblewithcurrentstructure

9. Frederik Beer, Jörg Robert 2. DW of PHR and PSDU (2): • Possiblesolutions: • Reverse theorderof FEC and DW block in themodulator • Useterminationsequencesbetween PHR and PSDU (asdefined in Fig. 148 (4g) and Fig. 167 (4k)

10. Frederik Beer, Jörg Robert 3. Channelpage (1): • 4g defines a widerangeoffrequencybands, channelsandmodulationtypes • ChanCenterFreq0does not showanyparticularpattern:

11. Frederik Beer, Jörg Robert 3. Channelpage (2): • At 920-928 MHz band and MR-FSK OM #1 the last channelwouldbeexactly at thefrequency band boundary:

12. Frederik Beer, Jörg Robert General Suggestion: • Encouragetaskgroupstoinstall a verification & validation (V&V) process • Widelyused in otherstandardizationbodies • Currently V&V procedureassuggestion in the 4q group • Wouldbe additional tothechecksandproofreadingduringballoting