NICT PHY Specification Proposal

1 July 2017 IEEE P802.15 -17-0433-00-0008

2 IEEE P802.15 3 Wireless Personal Area Networks

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

Title Resolutions for discovery, synchronization and merging of PAC networks

Date July 11th, 2017 Submitted

Source Marco Hernandez (ITAM, NICT), Huan-Bang Li (NICT), F. Kojima (NICT)

Response In response to Call for Contributions to TG8

Abstract

Purpose For discussion in TG8

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. 5

2Submission Page 1 Hernandez (ITAM, NICT) 1 July 2017 IEEE P802.15 -17-0433-00-0008

1Contents

21. PD discovery (192)...... 2

32. Filtering during scanning (208)...... 2

43. Initial synchronization procedure (237, 239)...... 2 5 3.1 Transmission of synchronization signals (242)...... 2

64. Maintaining and re-synchronization procedures (264)...... 2 7 4.1 Re-synchronization procedure (265)...... 2 8 4.2 Merging of PAC networks (272, 274, 275, 279, 281, 282, 283)...... 2

95. Discovery information (285)...... 4 10

11. PD discovery (192)

2A PD indicates its presence to other PDs by transmitting its discovery information during the discovery 3period. PD’s discovery information shall contain the PD MAC address and the high level IDs: Group 4ID and Application ID as indicated in Table 5. This allows other PDs to perform fast PD discovery 5without necessarily peering, and denominated as one-way discovery as specified in clause XXX.

6When PDs are already peered in a PAC group, A PD can request the discovery information of a 7specific PD (unicast) or PAC group (multicast), denominated as two-way targeted discovery, or for any 8PD in range (broadcast), denominated as two-way untargeted discovery using command frames during 9the CAP, as specified in clause XX.

102. Filtering during scanning (208)

11“to block all reception” because channel scanning is only looking for energy.

123. Initial synchronization procedure (237, 239)

13 The MAC layerA PD shall search for the synchronization signal for at least five consecutive 14superframes, to acquire initial reference timing.

15If the MAC layer does not detect the synchronization signal, it shall start to transmit its synchronization 16signal with a timing of arbitrary choice and while keep listening for synchronization signals.

17Once the MAC layer detects the synchronization signals it shall perform as follows: Then, the MAC 18layer shall follow the procedure described in clause 6.7.1.1 and clause 6.7.1.2 until the synchronization 19condition is met. The synchronization condition is met if synchronization signals are correctly received 20and transmitted in three consecutive superframes; the MAC layer shall continue to derive its own 21timing from the detected synchronization signals and shall make a transition to maintaining 22synchronization procedure as soon as the synchronization condition is met..

23If synchronization signals are found during the scanning period, and the synchronization condition has 24been met, the PD shall derive its own timing from the detected synchronization signal and shall make a 25transition to maintaining synchronization procedure.

26If synchronization signals are found during the scanning period, but the synchronization condition is 27not met, the PD shall follow the procedure described in clause 6.7.1.1 and clause 6.7.1.2 until the 28synchronized condition is met.

29If thea already synchronized MAC layerPD fails to detect any synchronization signal during the 30synchronization period, the PDMAC layer shall start to transmit its synchronization signal with a 31timing of arbitrary choice.

323.1 Transmission of synchronization signals (242)

33The synchronization signals (see clause 10.2.1) are transmitted in the synchronization period using 34random access to avoid collision. The structure of synchronization period is illustrated in Figure 21. 35The length of synchronization period shall be 34 backoff slots, where one backoff slot is equivalent to 36the length of two OFDM symbols (the length of the synchronization signal). The structure of the 37synchronization period is illustrated in Figure 21.

384. Maintaining and re-synchronization procedures (264)

39The MAC layerA PD maintains its own timing reference based on the measurement of the arrival time 40of synchronization signals and following the adjustment of reference timing specified in clause 6.7.1.2.

14.1 Re-synchronization procedure (265)

2The re-synchronization condition is met when the synchronization signal is not received within five 3consecutive superframes, activating the re-synchronization procedure.

4If the condition for re-synchronization is not met, the PD shall adjust its own timing based on the 5detected synchronization signals.

6The re-synchronization procedure is identical to initial synchronization procedure, except that a the 7MAC PD uses its own timing as initial timing.

84.2 Merging of PAC networks (272, 274, 275, 279, 281, 282, 283)

9As network synchronization is achieved by the transmission and reception of the unique 10synchronization preamble or signal, when two independently synchronized groups of PDs approach 11each other and at least one PD is in range of both groups, the synchronization procedure results in a 12convergence of both groups to the same start time of their superframe, if their synchronization period 13overlaps.

14PDs synchronized to a given superframe (PAC network) getting closer to other superframes (PAC 15networks) under other synchronization timing (different start time of the superframe), will begin to 16converge to the same start time of their superframes by virtue of the synchronization procedure as 17specified in clause 6.7. This convergence to the same start time of superframes happens only when 18their respective synchronization periods are overlapped.

19If this merging of PAC networks start to happen, the PAC networks may allow such merging as 20specified in clause 6.7.4.1 or may not allow such merging as specified in clause 6.7.4.2.

21This merging of PAC networks could be either getting synchronized to a common superframe or stop 22by changing to another channel number as different PAC networks could be operating the discovery 23period and CFP resources differently, resulting in a significant increment of the PER during those 24periods and an increment of the probability of collision during the CAP.

25The initiator PD’s higher layer of a PAC group will indicate either going ahead with getting 26synchronized to a common superframe as describe in clause 6.7.4.1 or changing to another channel 27number as described in clause 6.7.4.2.

284.2.1 Merging of two PAC networks

29Two or more PAC networks meet when one or more PDs in one PAC network are in communication 30range of other PAC networks, and are operating in the same channel frequency, and their 31synchronization periods overlap. In this case, such PAC networks become synchronized and all PDs in 32such PAC networks have the same reference timing to a common superframe.

33can communicate with one or more PDs in another PAC network. Two PAC networks can meet each 34other when the PAC networks move or any obstacle separating the two PAC networks is removed. 35When two PAC networks meet, the PAC networks are merged or synchronized by making the PDs in 36the two PAC networks have the same reference timing. A PD may be merging to another superframe or 37PAC network if such PD withstand a high increment of the PER during the discovery period and CFP, 38or an increment of the probability of collision during the CAP.

39Discovery primitives must carry the source address

Superframe 1

SP DP PP CP

Superframe 2

SP DP PP CP

2 Figure 1—Two PAC networks out of synchronization 3

4Figure 1 illustrates two PAC networks superframes, where the reference timing of network 1 is ahead 5of the reference timing of network 2. The procedure that merges the two PAC networks in Figure 1 is 6as follows:

7A PD gets synchronized to the detected superframe by stopping transmission of synchronization 8signals in the synchronization period of the current superframe and starts transmitting the 9synchronization signals in the synchronization period of the detected superframe

10When a PD starts such synchronization process the PD maintains normal operation in the 11synchronization period, but operates in reception mode in the discovery period, peering period, and 12communication period, until it decides the merging process has been completed.

134.2.2 Avoiding the merging of PAC networks (281, 282, 283, 284)

14If the MAC layera PD of a given PAC network operating in the CFP experiences a high increment of 15the PER during the discovery period and CFP, or an significant increment of the probability of 16collisions during the CAP, it shall notify its next higher layer with the MLMEL- 17SYNCHRONIZATION-LOSS.indication primitive with the Status parameter set to 18SUPERFRAME_CONFLICT.

19The next higher layer PD mayshall issue the MLME-NOTIFICATION.request primitive . Upon 20reception of the MLME-NOTIFICATION.request primitive, the MLME shall send the the 21Reassignment command frame to the initiator PD.

22report it to the initiator PD with the Reassignment command frame. Upon reception of the 23Reassignment command frame, the MLME of the initiator PD shall issue the MLME- 24NOTIFICATION.indication primitive to inform the next higher layer with the parameter 25SUPERFRAME_CONFLICT:

26 a) If the next higher layer decides to allow the potential merging with another PAC network, it 27 sends out the MLME-NOTIFICATION.response primitive with the parameter 28 DO_NOTHING. Upon reception the MLME-NOTIFICATION.response primitive, the 29 MLME shall send the Reassignment command frame to the requestor PD with parameter 30 DO_NOTHING. Upon reception of the Reassignment command frame, the MLME shall issue 31 the MLME-NOTIFICATION.confirm primitive to inform the next higher layer. 32 Consequently, such PD’s MAC layer follows the process described in clause 6.7.4.1.

33 b) If the next higher layer decides to not allow the potential merging with another PAC network, 34 it sends out the MLME-SCAN.request with parameters Channel Page and Scan Channels set 35 to the current channel page and desired channel numbers to be scanned. Upon reception of the 36 MLME-SCAN.confirm primitive to inform the next higher layer of scanned channels, the next 37 higher layer decides to which channel number to switch the whole PAC network. The next 38 higher layer sends out the MLME-NOTIFICATION.request primitive with parameter

1 NewChannel with the value of the new channel number. Upon reception of the MLME- 2 NOTIFICATION.request primitive, the MLME shall broadcast the Reassignment Request 3 command frame with parameter NewChannel. Upon reception of the Reassignment Request 4 command frame with the new channel number in the parameter NewChannel, the MLME 5 shall issue the MLME-NOTIFICATION.indication primitive to inform the next higher layer 6 of every PD in the PAC network. The next higher layer sends out the PLDE-CONFIG.request 7 primitive with new channel number in the PHYCONFIG_VECTOR parameter as specified in 8 clause 9.7.1.11, and sends out the MLME-NOTIFICATION.response primitive with the 9 parameter NewChannel. Upon reception of the MLME-NOTIFICATION.response primitive, 10 the MLME shall send the Reassignment Response command frame to the Initiator PD. Upon 11 reception of the Reassignment Response command with parameter NewChannel, the MLME 12 shall issue the MLME-NOTIFICATION.confirm primitive to confirm that a PD will change to 13 operate in a new channel indicated in the NewChannel parameter in the next superframe.

15the initiator PD’s next higher layer shall issue the MLME-SCAN.request with parameters Channel 16Page and Scan Channels set to the current channel page and desired channel numbers. Upon reception 17of the MLME-SCAN.confirm primitive, the initiator PD shall indicate to which channel number the 18PDs in the PAC group will change with a Reassignment command frame. Upon reception of the 19reassignment command frame, PDs shall issue the PLDE-CONFIG.request primitive with new channel 20number in the PHYCONFIG_VECTOR parameter as specified in clause 9.7.1.11.

215. Discovery information (285)

22The discovery information consists of is contained in 21 octets specified and shall be defined as in 23Table 5. The group ID and application ID areand set by the PD’s next higher layer.

2Submission Page 5 Hernandez (ITAM, NICT)