Location Aided Routing (LAR) and Power Aware Routing Metrics (PAR)

T S Pradeep Kumar!http://www.nsnam.com

LAR

❖ Utilises the location information for improving the efficiency of routing by reducing control overhead!

❖ It uses GPS for obtaining the Geographical information

Zones in LAR❖ Two zones in LAR namely ExpectedZone and RequestZone!

❖ ExpectedZone is the zone where the destination is expected to be present based on the past location and its mobility. if such an information is not available, then the entire network is said to be the ExpectedZone!

❖ RequestZone - It is the zone in which the path finding control packets are permitted to be propagated. !

❖ If the sender nodes or the intermediate relay nodes are not present in this zone, then additional area will be selected for propagation.!

❖ But usually, the nodes outside the RequestZone discards the control packets.

LAR1❖ A RequestZone is framed that includes the Source node

and the ExpectedZone (rectangle region). When the source node is inside the ExpectedZone, the size reduces to be the ExpectedZone.!

❖ RREQ packet is forwarded every neighbor node and the packet will be discarded if the node is outside the RequestZone!

❖ RREP can be with current location, current time and in some cases speed of the node also.

LAR2

❖ This is based on the distance from the source to Destination node in the RREQ packet. !

❖ When an intermediate node receives this packet, it computes the distance to Destination and if it less, then it forwards the packet, else the packet is dropped.

Pros and Cons of LAR

❖ Pros!

❖ Reduces the control overhead!

❖ Bandwidth utilisation!

❖ Cons !

❖ Since this is based on GPS, may not be suitable if no such facility available

Power Aware Routing Metrics❖ Minimal Energy Consumption per packet!

❖ Energy consumed by a packet is the sum of energies required at every intermediate hops!

❖ Maximum Network Connectivity!

❖ Minimum variance in node power levels!

❖ distribution of load among all nodes to that all the nodes' power consumption distribute uniformly!

❖ Minimum Cost per packet!

❖ Function of state of node's battery!

❖ Cost of a node is calculated based on the battery discharge

Ref: Siva Ram Murthy, B S Manoj, Adhoc Wireless Networks, Architectures and Protocols