Mobility Management and Mobility Models

The capacity of mobile ad hoc networks becomes a constraint due to the mutual interference of concurrent transmissions between nodes. The mobility of nodes adds another dimension of complexity in the communication process. Several works in ad hoc network studied the impact of mobility on the network capacity and suggested virtual backbone network to solve the issues in mobility management. The mobility model represents the The mobility models for mobile ad hoc networks include:
  • Random walk

  • Random waypoint

  • Random direction mobility

  • Reference point group mobility model

  • Gauss-Markov

  • Manhattan grid model

  • Disaster area model

  • Random street model

There are several other mobility models are also available. The popular and commonly used mobility models for mobile ad hoc network are random walk, random waypoint, random direction mobility, and reference point group mobility model. The random walk is a simple mobility model based on random direction and speed while the random waypoint includes pause time specifications to nodes in addition to direction and speed. The random direction mobility makes the mobile hosts to move to the edge of the simulation area prior changing direction and speed. In reference point group mobility model, the nodes in the network are grouped into several groups. Each group has a logical center or leader that determines the group’s mobility behavior. The mobility models play a vital role in evaluating the ad hoc protocol performance.

Problem

Various mobility models should be applied to the network to create the dynamic network that creates a more realistic scenario. The performance of the routing protocol should be evaluated in dynamic networks.

Solution in NS2

  • In NS2, mobility models such as Random way point, Random direction, Random walk and group mobility model can be modeled.

  • The performance of the different routing protocols such as AODV, DSR and DSDVunder different mobility models can be evaluated using NS2.

  • Highly dynamic mobile adhoc network can be created using the above mentioned mobility models in order to evaluate the performance of the routing protocols under the dynamic nature of topology.

  • Random way point mobility model can be generated using the ns~\indep-utils\cmu-scen-gen\setdest.cc file is available in ns2 for the input parameters total nodes, simulation time, pause time, network area and speed.