# Adaptive Thermal-Aware Routing Protocol for Wireless Body Area Network
## 2 Related Work
#### Taxonomy of Routing Protocols in WBAN
In status update phase, the sink notifies all its neighboring nodes upon receiving any data packet by sending the packet's ID to decrease the power consumption. Shortest Hop Routing (SHR) is used to transfer the packet to the destination. However, it only considers average temperature metrics and having less Network lifetime and high end-to-end delay. Thermal-aware shortest hop routing protocol diminishes the overheating without influencing the packet delivery proportion, delay and power utilization of bio-restorative sensor hubs. [PERSON] et al. in [PERSON] et al. (2018) claimed that TSHR is optimal for those applications that have high priority data to exchange the packets to the destination. The copy of transmission packet is additionally considered in TSHR. It incorporates two stages: setup stage and routing stage. In setup stage, routing tables are created while in routing stage every node transmits the packets to the destination on the basis of the shortest path. [PERSON] et al. in [PERSON] et al. (2018) proposed a technique in which each sensor node is placed in different ring level. The ring level depicts the distance of each sensor node from the destination in the form of hop-count. [PERSON] et al. in [PERSON] et al. (2018), proposed an energy efficient and thermal-aware routing protocol for WBAN to diminish the temperature of nodes. In addition to diminish the delay for the critical data by utilizing heterogeneous bio-therapeutic sensor nodes MATTEMPT involves four stages that are initialization stage, routing stage, scheduling stage and data transmission stage. In initialization stage, all nodes broadcast the hello packet, while in routing stage, courses with fewer hop counts are chosen within the available routes based on the temperature and energy metrics. The sink nodes make a Time Division Multiple Access (TDMA) plan for all root nodes in the scheduling stage, while the root nodes send their data to the sink hub amid the data transmission stage. TMQoS is a thermal-aware multi-constrained intrabody routing protocol. The basic objective of this protocol is to keep the temperature of node at an adequate level. [PERSON] et al. in [PERSON] et al. (2018) proposed TMQoS, which is a proactive routing protocol that builds ongoing routing table which includes multiple shortest path routes. Beacon packet is used to exchange the information between sensor nodes for the formation and maintenance of routing table. The beacon packet is received by neighboring nodes through mac receiver module. Routing table constructor module is used for formation and maintenance of routing table in term of hop-count, delay and temperature value. It also has hotspot avoidance mechanism that keeps the packet away from hotspot area. Reliability Enhanced-Adaptive Threshold-based Thermal-aware Energy-Efficient Multi-hop Protocol (RE-ATTEMPT) is a thermal and energy efficient routing protocol. [PERSON] et al. [PERSON] et al. (2018) presented that sink is placed between the nodes and nodes are sorted in descending order in term of data rate. The higher data rate node is placed where mobility is less and low data rate nodes are placed at mobility area of human body. This protocol uses direct communication for critical data and multi-hop communication for non-critical data. The protocol is divided into five phases: initialization phase, routing phase, scheduling phase and data transmission phase. The initialization phase is responsible for calculating the distance of nodes from sink node in the form of hop-count by broadcasting \"Hello Message\". In this phase, all nodes are aware of their neighboring nodes, available routes and distance from sink. The routing phase is responsible for selecting an efficient route with less hop-count. In routing phase, critical data is directly sent to sink using direct communication while normal data is sent using multi-hop communication. In scheduling phase, time slot is assigned to sink and root nodes for communication of data. The root and sink nodes communicate within their assigned time slot.