# TAEO-A Thermal Aware & Energy Optimized Routing Protocol for Wireless Body Area Networks
## 2 Related Work  
The researchers have done immense work to bring the continual advancement of WBAN technology. This section explains the notable work of authors on WBAN. In [3], the authors proposed the Thermal Aware Routing Algorithm (TARA), which is a pioneer protocol in the thermal-aware WBAN. The work before TARA did not encompass the effects of temperature rise on the human body. RF communication and internal circuitry of the sensor are two major sources of heat generation. On the base of these sources, the hot-spots are identified. Data sensing, processing, and transmitting activate ultimately increase the temperature of a node. In TARA, a node monitors the transmission of packets by its neighbors. On this base of this data, it estimates the temperature rise of a node. When the estimated temperature reaches a threshold, the node is marked as a hot-spot. The traffic towards the hot-Spot node is withdrawn and then returned to the previous node in situations where all of the neighbors are hot-spot. The packet withdrawal strategy adds up the overhead of rerouting and leads to overall transmission delay. Power consumption is also increased due to additional rerouting. In [5], [PERSON] proposed the Least Temperature Rise (LTR) scheme to address the shortcomings of TARA. The idea of the coolest neighbor is introduced, i.e. lowest temperature node is opted as a data forwarder. The protocol implemented a counter for the number of hops to limit the stray packet and to avoid looping. When the limit is reached, the packet is eliminated or dropped from the network. A list of recently visited nodes is maintained to optimize the node selection process. If the coolest node is in that list, then the node with the second lowest temperature is selected. As LTR is based on a greedy approach, the packets undergo longer delays to reach destination, thus undermining the reliability of communication. In the same paper, the author proposed ALTR, which is an improved version of LTR. In this scheme, the Adaptive Threshold is used and, when the hop count limit is reached, the packet is not dropped or discarded, but it is forwarded to the destination using the shortest-path algorithm. The protocol successfully reduced the transmission delay. However, when a shortest-path algorithm is applied, the protocol allows the traffic through a hot-spot node. In the same paper [5], the Least Total Route Temperature (LTRT) protocol works by pre-identification of routes from source to destination, and thereby selecting the path with the least total route. In LTRT, the temperature of a sensor is treated as its weight and the total route from source to destination is calculated and the minimum cost total route is opted for communication. HPR [6] uses the Shortest-Hop algorithm for transmission of packets to the destination. It works by defining a temperature threshold and allowing transmission if the nodes temperature is below the specified limit. If a nodes temperature surpasses the threshold, then the packets are rerouted to a neighbor with the lowest temperature. The exchange of information related to the node's heat in between nodes for hot-spot detection is a major overhead. The Thermal-Aware Shortest Hop Routing (TSHR) scheme for in-vivo implementation of WBAN is presented in [7]. [PERSON] and [PERSON] presented a novel architecture with a two-phase implementation approach. The configuration of nodes and the exchange of necessary information are managed in the first phase. Whereas, the second phase implements the routing scheme and the packets are forwarded on the path with a minimum number of hops to the destination. In TSHR, two temperature thresholds are specified. The first limit is for maximum acceptable temperature by a node. The second limit is dynamic and established on the base of a neighbor's temperature. Afterward, the node inspects and, if neighbor's temperature exceeds the preset dynamic value, it is declared as a hot spot. In [8], Mobile-ATTEMPT (M-ATTEMPT) is proposed, which is an extension of ATTEMPT routing scheme.