Submission Title: Potential 802.15.4g issues Date Submitted: May 2014 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. Frederik Beer, Joerg Robert

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

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

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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 18.1.2.1 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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> May 2014 3. Channelpage (2): At 920-928 MHz band and MR-FSK OM #1 the last channel would be exactly at the frequency band boundary: Frederik Beer, Jörg Robert <author>, <company>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>