Medium Access Control (MAC) and Physical Layer (PHY) - CISE

4-June-07 P1901_PRO_016_r0
The rule shall be “the lowest MID, the best”, analyzing the MID as a number.
Then, one of the nodes of the worse BPL cell will register in the neighbor network using the Access Protocol, and it
will act as master of its BPL cell, distributing the token.
If one node does not perform this protocol it does not copy the MID inherited from its master, instead it fixes the
local MID to one of these values:
0x1FFFFF. Nodes that have not completed the Access Protocol.
0x130001. Nodes that have finished the Access Protocol.
Border node designation
The border node is the modem that will act as a bridge between the networks passing the token.
Once the interference is detected, the network with higher MID must decide which node within the BPL cell, will
perform registration.
Designation Rules
The master will select the Border Node with the following criteria:
Less hops, higher priority. This is, if the interference is detected by several nodes, the HE has preference over the
rest of the nodes; next TDRs placed one hop away; next repeaters with two hops, etc.
CPEs do not perform this protocol, only HEs and TDRs do. A node that detects only a CPE of a neighbor BPL cell
does not apply for becoming border node.
Notification protocol
To centralize the decision, the HE of the BPL cell decides which node will perform negotiation, interchanging CCP
packets. Since the interference will not be detected by all the nodes simultaneously, a guard time may be kept before
designating the border node in order to know all the information.
If any node detects the interference (sniffing a better MID), it transmits an Interference Detection Packet (IDP),
containing the own MAC, the neighbor MAC sniffed, the MID sniffed, the local number of hops and the identity of
the node detected (HE or TDR). When the packet is received by a node, it has to check if is coming from one of its
slaves, then the information is copied and retransmitted to its master, then the packet will arrive finally to the HE of
the BPL cell. To avoid flooding the network, the IDPs have to be sent with a minimum period of 10 seconds
Submission page 271 UPA-OPERA