The vehicular nodes under NLOS situation should be figured effectively, so that the emergency vehicle can communicate to the NLOS node at accurate time period with decreased overhead were the time period depend upon the high degree of channel utilization. In this paper we are going to discuss many such methods proposed by researches by considering the advantages and drawbacks. | ISSN:2249-5789 Archanaa et al, International Journal of Computer Science & Communication Networks,Vol 9(1),01-09 METHODOLOGIES TO IDENTIFY NON LINE OF SIGHT: A SURVEY R. Kaviarasan[1] Assistant Professor Afraa Fathima[2] Archanaa[3] Chandralayka[4] julaikaz@ Archanaadhashi98@ chandraviji4@ Suganthi[5] Suganthisukku244@ kaviarasanr64@ Dept of CSE Alpha college of Engg&Tech Puducherry,India Abstract An quality network to create risk free landscape which facilitate least clutterted up any risk free interaction betwixt vehicular nodes is vehicle ad hoc network (VANET). The challenges in VANET is transmission of security message betwixt vehicles during high cluttered environment. One of the major challenges in VANET is Non Line Of Sight (NLOS), in which broadcasting the data to crisis vehicle is being arduous. The vehicular nodes under NLOS situation should be figured effectively, so that the emergency vehicle can communicate to the NLOS node at accurate time period with decreased overhead were the time period depend upon the high degree of channel utilization. In this paper we are going to discuss many such methods proposed by researches by considering the advantages and drawbacks. Keywords: VANET; NLOS; Broadcast; Road side unit; On board unit. 1. Introduction Vehicular Ad hoc network based on ambulant junction (transport embedded with sensors), fixed foundation (Road Side unit) as well as wireless link towards allow them into provide aid on each further. The most important service provided by these networks is driving safety[1]. Almost million people were passing on road calamity and extra 20-50 millions are get injured worldwide. Road calamity ranked as 9th leading cause of death[2]. Some survey shows that 60% of accidents can be avoided if the driver gets the warning even before half a second of the accident[3]. The World Health Organization published an International status report on road safety in .
