# Adaptive Thermal-Aware Routing Protocol for Wireless Body Area Network
## 3 Proposed Method of ATAR
### Adaptive Thermal-Aware Routing Protocol  
The primary concern for WBAN network life is the evasion of temperature rise. The maintenance of the network stability and efficiency are the main challenges that must be dealt to find the optimal  
Figure 8: Placement and communication of nodes on the human body. forwarder nodes from the source to destination with less temperature rise for data transmission. This issue is addressed individually by existing routing protocols. Nonetheless, using the same route (optimal route) with less temperature of the node for communication of data may lead to overheat of that route or death of nodes on that route. The above-mentioned problem is resolved in this research by presenting the protocol \"ATAR--Adaptive Thermal-Aware WBAN Routing Protocol\". The WBAN is derived from WSNs and Multipath ring routing is routing protocol in WSNs. We enhance the famous MRRP routing protocol in terms of temperature. The proposed protocol has a mechanism of optimal forwarders selection to avoid frequent partitioning due to temperature rise of implanted sensor nodes. The probability of selection is dependent on temperature rise metric and selection of each discovered forwarder node. The forwarder nodes selection is based on the probability value of temperature rise therefore, multi-path communication is used instead of single-path used continuously during the communication. The ATAR is a reactive source initiated protocol where setup packet is used to maintain the information of neighboring nodes. The proposed ATAR scheme consists of two phases  
* Initialization Phase
* Data Transmission Phase  
In the initialization phase, the distance of each node is calculated from destination in terms of hop-count. In this phase, the network is organized into different levels like R1, R2 and R3 etc. Considering the Figure 9a, R1 represents the first level containing two nodes (i.e., s1, s2) and their distance from the sink is 1 in terms of hop-count. Similarly, R2 contains four nodes and their hop-count distance from the sink node is 2 and R3 contains 3 nodes and their distance from the sink node is 3 as shown in Figure 9a. Each node in the sink's neighbor that receives this packet, will update its ring level field by incrementing 1 in the ring level value and rebroadcasts the setup packet. The process of rebroadcasting and updating ring level will continue until the entire network is organized into levels by assigning each node by its ring level, as shown in Figure 9b. At the end of this phase, every node within the network will aware of its ring level that depicts distance of the node from the sink in the form of hop-count. The format of the setup packet in initialization phase is shown below. The setup packet is broadcasted by the Source ID which is the ID of the node. The destination address of the packet is shown by Destination ID and the Temperature represents the temperature of a node. Figure 9: ATAR: Initialization Phase. The primary goal of the initialization phase is to generate ring level through a setup packet, as shown in Figure 9a. Each node broadcasts a setup packet to explore its neighbors, as shown in Figure 9b. When a node receives a setup packet, it considers itself in level n, if the hop-count is n. If the packet is received from the node with smaller ring level then the node updates its ring level with received ring level. When the setup packet is sent by the sink, the receiving node verifies that whether its level is \(-1\), if the level value is \(-1\), then it accepts the packet otherwise discards the packet, as shown in Figure 10. When packet is received, the current node will increment its level by 1 and update the packet header with its level and temperature value and rebroadcast the packet. The process of rebroadcasting and updating ring level will continue until the network is organized into levels by assigning each node by its ring Level.