Review Article

Joint Channel Assignment and Routing in Multiradio Multichannel Wireless Mesh Networks: Design Considerations and Approaches

Table 3

State-aware channel assignment/routing proposals summary.

Work⁢State awareApproachNotes/limitations
Channel reassignmentFlow rerouting

[35]Cost is based on channel-link reassignmentNot applicable since a fully connected topology and fixed predefined paths are considered(i) Reorder channel in the new CA to reduce the cost during migration from existing cluster to the new cluster(i) Out-of-order problem
(ii) Assigning channels to all logical links affects the channel diversity
(iii) Performance degradation if the traffic load sequences are highly uncorrelated

[85]Cost is based on channel-link reassignmentNot applicable since a fully connected topology is considered(i) Previous channels are reassigned to links if they are among the set of channels which best reduce the interference and do not violate radio constrains(i) Internet traffic information is collected at the gateway
(ii) Performance degrades with small number of radios due to ripple effect on channel reassignment
(iii) Assigning channels to all logical links affects channel diversity

[29]Cost is based on channel-link reassignmentNot applicable since a fully connected topology and predefined paths are considered(i) Effective data for each channel is computed and channel with the highest effective capacity is selected. If the channel is not previously assigned to that link reconfiguration cost is subtracted from the effective data value(i) Out-of-order problem due to multipath
(ii) Assigning channels to all logical links affects channel diversity
(iii) The channel assigned to a link will be considered as final assignment; thus, earlier assignments are not aware of later assignments; this may lead to an improper final channel assignment
(iv) Due to radio constraint some links will be forced to assign more congested channels and this will result in inefficient channel assignment

[84]Cost is based on channel-node reassignmentNot addressed(i) Starts from the existing CA and finds new CA by making some adjustment on the previous one
(ii) Number of radio-channel reassignments is constrained to a predefined number
(i) Performance degrades with small number of radios due to ripple effect on channel reassignment
(ii) Transmission rate is jointly solved with CA links to optimize the network performance

[37]Cost is based on channel-link reassignmentNot addressed(i) Starting from existing channel assignment, a new channel is assigned to a link if it does not violate the radio constraints and reduces the interference
(ii) Number of link-channel reassignments is constrained to a predefined number
(i) Performance degrades with small number of radio interfaces and due to that reassignment is restricted to channels that do not violet the radio constraints
(ii) Assigning channels to all logical links affects channel diversity
(iii) Flow-level routing introduces overhead to the routing procedure and requires a routing entry of each flow in routing tables. This is impractical for high number of flows

[58]Not addressedConsidered, where rerouting cost is based on the number of flows having different routing path(i) Heuristic routing based on Dijkstra algorithm
(ii) The number of flows which allowed having new routes is constrained to a predefined value
(i) Flow rerouting cost is not accurately defined. For instance, two new flow path assignments may result in different disruption while both are considered equally in rerouting cost