Low Overhead Localized Routing in Mobile Ad Hoc Networks

Table 1

Summary of related works.

	Operations
ERS [14]	Flooding scope of RREQ is limited to minimum for the first route discovery. If fails, it will be conditionally increased for next attempt.
BERS [15]	After a route is established successfully, RREQ packets which were flooded to discover the route will no longer be forwarded.
EEERS [16]	Prevent a forwarding node which has no successor node from rebroadcasting RREQ packet unnecessarily.
Spray & wait [18, 19]	Forward data packet with a limited number of replications during spray phase and stop all forwarding activities in the wait phase.
Spray & focus [20]	Improve the wait phase of spray and wait by allowing data packet to be forwarded if an encountering node recently met the destination.
LAR [25], PAR [26–28]	Limit the flooding into a specific area for geographic-based routing by using location information. GPS is required.
IBR-AODV [29]	Each node listens to the transmission of a data packet and will advertise itself as the new bridge node if it overhears retransmission of the data packet for several times (which indicates that the route is breaking). Promiscuous mode must be enabled in all nodes.
SRR [30]	Find a new backward path to a source if a RREP packet is undeliverable.
BRD [31]	Route discovery is performed by both source and destination where flooding scope is divided into two smaller areas.
DOA [32]	Use Dynamic Source Routing (DSR) for global flooding scope and use AODV for local flooding scope.
WAL [34]	Drop a new incoming RREQ packet if the node’s workload (calculated from queue size) exceeds the maximum threshold.
Detour [35]	Drop a new incoming RREQ packet if a node is congested and inform its predecessor node to find a new detour path.
EXPANSION [36]	Use signal strength to determine whether a current path is stable or not. A bridge node will be inserted to the current unstable path.
MH [21]	Broadcast a limited scope of a RREQ packet to find a new bridge node which can connect to the downstream node of the broken link to repair route breakage.
[22]	Both the destination of a RREQ packet and the unreachable next hop node of the previously broken path can respond to the RREQ in order to increase the success of route discovery.
[23]	Limit broadcast scope of RREQ packet originated from the local repair mechanism.
[24]	Apply multipoint relay (MPR) algorithm to prune some nodes from rebroadcasting RREQ packet. List of 1-hop neighbors is distributed along with periodic hello packets in order to classify MPR nodes.
NC [37]	Allow only nodes which have been recently forwarded data packets in a specified period to rebroadcast new incoming RREQ packet.
EBR [38]	Use a history of contact information to determine an appropriate amount of message copies for each encountering node.
Extended AODV [39]	Forward a RREQ packet by unicast through a recently broken path.
DRCA [40]	Perform path shortening to reduce overhead of data packet forwarding.
QL [17]	The propagation of RREQ packet is limited to not farther than preconfigured number of hops from relay nodes of a recently broken path. Some relay nodes of the old path will be a member of a new path.
[41]	Improve the local repair mechanism of QL to avoid initial global flooding stage.
QL-O [42]	A RREQ packet is rebroadcasted freely by 1-hop neighbors of a previously broken path only.