1. Splicing in a Mesh Network
Month Year
doc.: IEEE yy/xxxxr0
May 2005
Splicing in a Mesh Network
Date:
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Mathilde Benveniste, Avaya Labs
John Doe, Some Company

2. ‘Splicing’ in a mesh network
May 2005
‘Splicing’ in a mesh network
Mathilde Benveniste
Mathilde Benveniste, Avaya Labs

3. May 2005
Introduction
The CCC protocol that enables reservation of mesh traffic (MT) channels to be made on a single control channel monitored by all MPs is presented starting in Doc IEEE r0
We have discussed how interference from users of the same RF spectrum band in various BSSs associated with the mesh can be prevented
We are concerned here with interference caused by independent systems operating on the same RF spectrum
Two types of interferers are considered:
Those operating on channels used for mesh traffic
Those operating on the mesh control channel
Mesh traffic channels serving independent co-channel users are avoided by limiting channel selection within a set of permissible channels for each mesh point
We show how the control channel can be changed or “spliced” to operate on two different physical channels in order to avoid interference from mesh-independent stations
Mathilde Benveniste, Avaya Labs

4. Permissible Set of MT channels
May 2005
Permissible Set of MT channels
APs that are independent of a mesh may operate in the neighborhood of mesh points on the same channel. As a consequence the channel should be avoided as either a control channel or a mesh traffic channel
A "permissible“ set of channels is maintained by an MP; the MP select its MT channels from the permissible set
The permissible set contains channels that are not heavily loaded with non-mesh traffic or traffic from a non-mesh-associated BSS
Channels are monitored regularly in order to avoid such channels from being included in the permissible set, which is updated over time 
If an independent AP powers on and chooses to operate on one of the permissible channels, that channel is removed from the permissible set.  
Mathilde Benveniste, Avaya Labs

5. May 2005
MT Channel NAV
A NAV is maintained by a MP on all channels on the permissible set
The NAV of a channel is updated by
NAV setting requests for the channel reserved transmitted on the control channel, and
NAV setting requests transmitted on each traffic channel by any stations/APs that may be operating on that channel and are received by a MT radio while tuned to that channel 
If the MP has a fixed MT channel assigned to it, it will be synchronized always with all NAV setting requests on the MT channel  
If the MP switches MT channels,
Collisions are possible if the MRTS asks for such a channel before the latter is removed from the permissible set
The MP performs carrier sensing before transmitting and will back off to avoid such collisions 
NAV synchronization can be achieved with greater probability by tuning to the MT channel before the MP is ready to transmit
Tuning should occur no latter than the generation and queueing of a MRTS or MCTS
Mathilde Benveniste, Avaya Labs

6. Control Channel Change
May 2005
Control Channel Change
Independent APs operating in the mesh area, on the same channel as the mesh control channel, may force a nearby MP to request a change of the control channel
Such a change is accommodated either by forwarding the control channel change request to all MPs, or by “splicing” the channel
We show how these requests are performed
Mathilde Benveniste, Avaya Labs

7. Splicing: changing control channel
May 2005
Splicing: changing control channel
Splice
Authorizing MP
Control channel
1 independent AP, L,
operates in the mesh area
on the same channel as the
mesh control channel;
MP G requests control
channel change
Traffic channel B H A
Mesh point F F
Independent point
Authorizing MP L
Requesting MP G D
Authorizing MP E I
A MP may send requests to its mesh neighbors for permission to use a different control channel
If the request is authorized,
The requesting MP will tune its control radio to the requested channel
If an authorizing MP has no other mesh neighbors, it will tune its control radio to the requested channel
If an authorizing MP has other mesh neighbors it will tune a MT radio to the requested control channel
In that case, if the authorizing MP has no additional MT radios, it will use the control channels for mesh traffic to its mesh neighbors
Mathilde Benveniste, Avaya Labs

8. Forwarding a request May 2005
Forwarding MP
Control channel
Forwarding MP
Authorizing MP
Traffic channel B H
1 independent AP, L, operates
in the mesh area on the same channel as the mesh control channel; MP G requests control
channel change. Request is forwarded A
Authorizing MP
Mesh point F F
Independent point L
Requesting MP
Authorizing MP G D
Authorizing MP E I
If a MP receives a request for control channel change, it may do one of the following:
Accept the request
Forward the request to all other neighbors, or
Decline the request
Mathilde Benveniste, Avaya Labs

9. Procedure for Splicing
May 2005
A MP may request its mesh neighbors for permission to use a different control channel
If a MP receives a request for control channel change, it may do one of the following:
Accept the request
Forward the request, or
Decline the request
A MP that accepts or declines a request or receives notice that a request it forwarded is accepted will notify the mesh neighbor from which it received the request
A MP will consider its own or forwarded request accepted if all mesh neighbors to which it sent the request indicate that the request is accepted
A request is authorized if it is considered accepted by the requesting MP
If a request is authorized
A MP that forwarded or submitted an authorized request will tune its control radio to the requested channel
If a MP that accepted an authorized request has no mesh neighbors other the MP that sent the request, it will tune its control radio to the requested channel
If an authorizing MP has mesh neighbors other than the MP that sent it the request it will tune a MT radio to the requested control channel and use it for control traffic
In that case, if the authorizing MP has no additional MT radios, it will use the control channels for mesh traffic to its mesh neighbors
If the request is not authorized, the requesting MP may resubmit a request for a different control channel
Mathilde Benveniste, Avaya Labs