## 4 Proposed SARP Routing Protocol for BASNs
### Working Principle of Sensors in SARP
#### 4.4.1 Updating Neighbors with Recent Information  
A self-optimized, bio-inspired routing protocol for quality-aware data gathering is required for the next generation of wireless body area sensor networks. The proposed scheme, by employing the various types of biosensors, senses the human body and sends this information in a collaborative manner to the remote physician for monitoring a patient's health condition in real time. In this respect, the key objective is to establish a set of energy-efficient and highly stable routing paths over a set of highly stable clustering architectures to provide quality-aware data transmission to the static coordinator. The entire routing architecture of the proposed scheme is divided into two main phases, namely, cluster formation and routing path selection, over a set of group leaders between the source and destination in BASNs. The patient or the remote doctor initiates the data collection process on demand by sending multiple data collection messages (\(\mathit{c\ell}\mathit{eect\_data}\)) to the coordinator located on the human body. The coordinator, after successfully receiving the first \(\mathit{c\ell}\mathit{eect\_data}\) message, looks in its routing table for any available path to the destination node. The coordinator immediately performs route discovery and broadcasts multiple route discovery messages (\(\mathit{dis\_route}\)) to the neighboring biosensor nodes in its communication range only if a path to the destination is not present or is invalid. The \(\mathit{dis\_route}\) message contains information of the coordinator identity, distance, and location on the body. After successfully receiving the \(\mathit{dis\_route}\), each biosensor node creates a new routing table only if it does not exist before for storing the coordinator information in its routing table, and it replies to the coordinator node via a reply message (\(\mathit{rep\_msg}\)) only if it is a single hop away to the sink. The reply message (\(\mathit{rep\_msg}\)) contains the identity, residual energy, distance information, and its location on the body. The coordinator, after receiving the \(\mathit{rep\_msg}\) message successfully from the sender, stores its identity and other information, and marks it a single hop neighbor in its neighboring routing table. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value (s)** \\ \hline Channel & Body channel \\ Network topology & Deterministic \\ Biosensor deployment area & \(2\times 3\) m\({}^{2}\) \\ Sink location area & \(30\times 50\) cm\({}^{2}\) \\ Initial node energy & \(0.5\) J \\ Initial sink energy & \(10\) kJ \\ Number of biosensor nodes & \(25\) \\ Number of sink nodes & \(1\) \\ Number of female ions & \(10\) \\ Number of male ions & \(14\) \\ Cost of high transmission & \(30\) nJ/bit \\ Cost of low transmission & \(23\) nJ/bit \\ Cost of reception & \(7\) nJ/bit \\ Idle power & \(0.90\) nJ \\ Data aggregation power & \(5\) nJ/bit/signal \\ Signal amplifying power & \(10\) pJ/bit/m\({}^{2}\) \\ High communication range of sensors & \(0.5\) m \\ Low communication range of sensors & \(0.3\) m \\ Transmission range of sink & \(1\) m \\ Line-of-sight (LOS) & \(3.38\) \\ Non-line-of-sight (NLOS) & \(5.90\) \\ Bandwidth & \(20\) MHz \\ Maximum data rate & \(151.8\) kbps \\ Packet size & \(3\) kb \\ Control packet size & \(50\) bits \\ Packet generation rate & \(0.01\)\(\sim 0.1\) packets/s \\ Memory size & \(0.3\) MB \\ Modulation scheme & DPSK \\ Physical layer & IEEE 802.15.6 \\ Antenna & Omnidirectional \\ Simulation time per epoch & \(80\) s \\ Number of runs & \(53\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Values of parameters used in SARP. Then, each biosensor, by considering the time intervals, broadcasts the received \(dis\_route\) messages in its communication range and waits for the neighbor reply messages.