Connectivity based technique for localization of nodes in wireless   sensor networks
  We propose a localization algorithm for wireless sensor networks, which is simple in design, does not involve significant overhead and yet provides acceptable position estimates of sensor nodes. The algorithm uses settled nodes as beacon nodes so as to increase the number of beacon nodes. The algorithm is range free and does not need any additional piece of hardware for ranging. It also does not involve any significant communication overhead for localization. The simulation and results show that good localization accuracy is achieved for outdoor environments. 
Muhammad Farooq-i-Azam, Muhammad Naeem Ayyaz, Saleem Akhtar
cs.NI cs.DC