ﯾﮏ روﯾﮑﺮد ﻣﻘﺎوم و ﻫﻮﺷﻤﻨﺪ ﺷﺪه ﺑﺮاي ﭘﺨﺶ ﭘﯿﺎم در ﺷﺒﮑﻪﻫﺎي ﻣﻮردي ﺑﯿﻦ ﺧﻮدروﯾﯽ ﺑﺮاي ﻣﻮارد اﺿﻄﺮاري

A Robust and Smart Approach to Message Broadcasts in Vehicular Ad Hoc Networks for Emergency

ﺷﺒﮑﻪﻫﺎي ﻣﻮردي ﺑﯿﻦ ﺧﻮدروﯾﯽ ﺑﺎ ﻫﺪف اﯾﺠﺎد اﯾﻤﻨﯽ و راﺣﺘﯽ ﺑﺮاي راﻧﻨﺪﮔﺎن و ﻣﺴﺎﻓﺮان اﯾﺠﺎد ﺷﺪه اﺳﺖ. در اﯾﻦ ﺷﺒﮑﻪﻫﺎ، ﺗﻐﯿﯿﺮات زﯾﺎد ﺗﻮﭘﻮﻟﻮژي، ﭼﺎﻟﺶﻫﺎي زﯾﺎدي را ﺑﺮاي ﺗﺤﻮﯾﻞ ﮐﺎرآﻣﺪ دادهﻫﺎ اﯾﺠﺎد ﻣﯽﮐﻨﺪ. روش اﻧﺘﺸﺎر داده ﻣﯽﺗﻮاﻧﺪ ﻧﯿﺎزﻫﺎي ﭘﺨﺶ ﭘﯿﺎم اﺿﻄﺮاري را ﺑﺮآورده ﮐﻨﺪ. اﻧﺘﺸﺎر دادهﻫﺎ در اﯾﻦ ﺷﺒﮑﻪﻫﺎ ﮐﺎري ﭘﯿﭽﯿﺪه و ﻣﻬﻢ اﺳﺖ زﯾﺮا ﺗﻐﯿﯿﺮ زﯾﺎد ﺳﺮﻋﺖ ﻣﺎﺷﯿﻦﻫﺎ، اﺣﺘﻤﺎل وﺟﻮد ﺷﮑﺎفﻫﺎي ارﺗﺒﺎﻃﯽ را ﺑﺎﻻ ﻣﯽﺑﺮد. در اﯾﻦ ﺷﺒﮑﻪﻫﺎ ﺗﺤﻮﯾﻞ ﺳﺮﯾﻊ و ﺗﻀﻤﯿﻨﯽ ﺑﺎﻻي ﺑﺴﺘﻪﻫﺎ داراي اﻫﻤﯿﺖ ﺑﺴﯿﺎري اﺳﺖ. در اﯾﻦ ﻣﻘﺎﻟﻪ روﺷﯽ ﭘﯿﺸﻨﻬﺎد ﺷﺪه ﮐﻪ در آن ﮐﺎﻧﺎل ارﺗﺒﺎﻃﺎت ﺑﺮد ﮐﻮﺗﺎه اﺧﺘﺼﺎﺻﯽ )DSRC( ﺑﺎ ﺳﻪ ﻧﻮع اوﻟﻮﯾﺖ ﻣﺘﻔﺎوت ﺑﺮاي ﭘﯿﺎمﻫﺎي اﯾﻤﻨﯽ ﺗﻘﺴﯿﻢ ﻣﯽﮔﺮدد. ﺟﻬﺖ اﻧﺘﺸﺎر ﭘﯿﺎم ﺑﺮاي ﻫﺮ ﮐﻼس ﯾﮏ ﮔﯿﺮﻧﺪه ﭘﻮﯾﺎ ﺗﻌﺮﯾﻒ ﻣﯽﮔﺮدد، ﺑﺮاي ﺟﻠﻮﮔﯿﺮي از اﻧﺘﺸﺎرات اﻓﺰوﻧﻪ و اﺳﺘﻔﺎده ﺑﻬﯿﻨﻪ از ﭘﻬﻨﺎي ﺑﺎﻧﺪ، ﺷﺮط ﻣﺎﺑﯿﻦ ﺑﻮدن ﮔﺮه ﻣﺒﺪأ و ﮔﺮه اﻧﺘﺸﺎر دﻫﻨﺪه در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﺷﺪه اﺳﺖ. روش ﭘﯿﺸﻨﻬﺎدي ﺑﻪ ﻫﯿﭻﮔﻮﻧﻪ ﺳﺨﺖاﻓﺰار ﯾﺎ ﮐﻨﺘﺮلﮐﻨﻨﺪه ﻣﺮﮐﺰي ﻧﯿﺎز ﻧﺪارد. ﺑﻪﻣﻨﻈﻮر ﺗﺤﻠﯿﻞ ﻣﯿﺰان ﮐﺎراﯾﯽ، روش ﭘﯿﺸﻨﻬﺎدي را ﺑﺎ روشﻫﺎي ﺗﻘﺴﯿﻢﺑﻨﺪي و ﭘﺨﺶ ﺑﺮﻧﺎﻣﻪرﯾﺰيﺷﺪه ﺗﻄﺒﯿﻘﯽ )ASPBT( و ﭘﺮوﺗﮑﻞ اﻧﺘﺸﺎر دادهﻫﺎي اﻧﻄﺒﺎﻗﯽ )AddP( ﻣﻘﺎﯾﺴﻪ ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ارزﯾﺎﺑﯽ ﺗﺤﻠﯿﻠﯽ و ﺷﺒﯿﻪﺳﺎزي ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ در روش ﭘﯿﺸﻨﻬﺎدي ﺗﺎﺧﯿﺮ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ روشﻫﺎي ASPBT وAddP ﺑﻪﺗﺮﺗﯿﺐ 5 درﺻﺪ و 14 درﺻﺪ ﮐﺎﻫﺶ ﯾﺎﻓﺘﻪ اﺳﺖ. ﻧﺮخ ﺗﺤﻮﯾﻞ ﺑﺴﺘﻪ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ روشﻫﺎي AddP و ASPBT ﺑﻪﺗﺮﺗﯿﺐ 37 درﺻﺪ و 0/83 درﺻﺪ ﺑﻬﺒﻮد ﯾﺎﻓﺘﻪ اﺳﺖ. ﻫﻤﭽﻨﯿﻦ ﻧﺮخ ﺗﺼﺎدم روش ﭘﯿﺸﻨﻬﺎدي 4 درﺻﺪ و 11 درﺻﺪ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ روشﻫﺎي ASPBT و AddP ﺑﻬﺒﻮد ﯾﺎﻓﺘﻪ اﺳﺖ.

Vehicular ad hoc networks are designed to provide safety and comfort for drivers and passengers. In these networks, many topological changes create many challenges for efficient data delivery. The data dissemination method can meet the needs of emergency message broadcasting. Disseminating data on these networks is a complex and vital task because the highly variable speeds of vehicles increase communication gaps. In these networks, fast and guaranteed high delivery of packets is essential. In this paper, a method is proposed in which the dedicated short range communication (DSRC) channel is divided into three different types of priorities for beacon messages. A dynamic receiver is defined for each class to broadcast the message. The technique of considering the intermediate condition between the source node and the sender node is used to prevent the broadcast of redundancy and the optimal use of bandwidth. The proposed method does not require any hardware or central controller. In order to analyze the efficiency, the proposed method is compared with ASPBT and aadaptive data dissemination protocol (AddP) methods. The analytical evaluation and simulation results show that our proposed method is superior to other methods in terms of efficiency.