Hello Tengfei The text below:
whether there is any incoming frame on those cells could be understood like it is a unicast frame to this node. In fact the text should describe promiscuous listening of traffic between arbitrary nodes. I’m OK to use carrier sense since an interference is only interesting if it is TSCH. I would suggest As a consequence of randomly cell selection, there is a non-zero chance that nodes in the vicinity installed cells with same slotOffset and channelOffset. An implementer MAY implement a strategy to monitor the candidate cells before adding them in CellList to avoid collision. For example, a node MAY maintain a candidate cell pool for the CellList. The candidate cells in the pool are pre-configured as Rx cells to promiscuously listen to detect transmissions on those cells. If IEEE802.15.4 transmissions are observed on one cell over multiple iterations of the schedule, that cell is probably used by a TSCH neighbor. It is moved out from the pool and a new cell is selected as a candidate cell. The cells in CellList are picked from the candidate pool directly when required. All the best, Pascal From: 6tisch <[email protected]> On Behalf Of Tengfei Chang Sent: vendredi 23 août 2019 14:11 To: 6tisch <[email protected]> Subject: [6tisch] cell rules in MSF Hi all, As we discussed in IETF 105, we may need some way to monitor the candidate cells to schedule before adding them. Hence the following paragraph is added in version 06: As a consequence of randomly cell selection, there is a non-zero chance that nodes in the vicinity installed cells with same slotOffset and channelOffset. An implementer MAY implement a strategy to monitor the candidate cells before adding them in CellList to avoid collision. For example, a node MAY maintain a candidate cell pool for the CellList. The candidate cells in the pool are pre-configured as Rx cells to listen whether there is any incoming frame on those cells. If any IEEE802.15.4 frames are received within a pre-defined duration on one cell, that cell will be moved out from the pool and a new cell is selected as a candidate cell. The cells in CellList are picked from the candidate pool directly when required. Please let me know if you have any comments on this fix. Thanks! Tengfei -- Chang Tengfei, Postdoctoral Research Engineer, Inria
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