## 3 Basic System Operation
### SBD Routing
\begin{table}
\begin{tabular}{l l} \hline \hline
**Parameter** & **Setting** \\ \hline Field Size & 60 \(\times\)60 m\({}^{2}\), 90 \(\times\)90 m\({}^{2}\), 120 \(\times\)120 m\({}^{2}\), 150 \(\times\)150 m\({}^{2}\) \\ Number of Nodes (\(n\)) & 80 (3600 m\({}^{2}\)), 180 (8100 m\({}^{2}\)), 320 (14,400 m\({}^{2}\)), 500 (22,500 m\({}^{2}\)) \\ Member Node Density (\(f_{\text{w}}\)) & 1 node/56.25 m\({}^{2}\) \\ Sector Head Node (SH) Density (\(f_{\text{sn}}\)) & 1 node/225 m\({}^{2}\) \\ Radio Range (member node) & \textasci{}8 m \\ Radio Range (SH) & \textasci{}20 m \\ Transmission Power & 0 dBm (\(SH\)), \textasci{}5 dBm (member node) \\ Power Consumption in Sending and Receiving Messages & 57.42 mW (\(SH\)), 46.2 mW (\(member\ node\)) \\ Power Consumption Per Sensing & 0.02 mJoule \\ Data Rate, Modulation Type, Bits Per Symbol, Bandwidth, & 250 Kbps, PSK, 4, 20 MHz, 194 MHz, -100 dBm, -95 dBm \\ Noise Bandwidth, Noise Floor, Sensitivity & 250 Kbps, PSK, 4, 20 MHz, 194 MHz, -100 dBm, -95 dBm \\ pathLossExponent & 2.4 \\ Initial Average Path Loss (\(PL(d_{0})\)) & 55 \\ Reference Distance (\(d_{0}\)) & 1.0 m \\ Gaussian Zero-Mean Random Variable (\(X\),) & 4.0 \\ MAC Protocol, Maximum Transmission Retries & SMAC [16], 2 \\ SMAC Acknowledgment, Synchronization, RTS, CTS Packet Size & 11, 11, 13, 13 bytes \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Simulation parameters. ### SBD Performance

The performance of SBD is evaluated in comparison with DD, GPSR, LEACH and Car Pooling routing. The candidate routing protocols for evaluation were chosen from the literature based upon their being an acceptable representation of existing comparative techniques. DD, GPSR, and Car Pooling were used in different DCS schemes over the last decade. On the other hand, SBD, LEACH and Car Pooling are cluster routing algorithms. DD, a data-centric routing technique, floods the query to a region of interest that contains the data sought for. One of the widely used point-to-point routing algorithms is GPSR, which is used in earlier DCS schemes. GPSR implements two distinct routing algorithms--greedy forwarding algorithm and perimeter forwarding algorithm. Greedy forwarding algorithm moves packets progressively closer to the destination at each hop. At a void situation, where there is no greedy path, it switches to perimeter forwarding mode, in which a packet traverses consecutively closer along a planer sub-graph of the full radio network connectivity graph. This continues until it reaches to a node closer to the destination where greedy forwarding resumes. In LEACH and Car Pooling, sensor nodes are grouped into clusters with a Cluster Head (CH) for each group. A CH is responsible for data aggregation and communicating with other CH on behalf of the cluster nodes. However, unlike LEACH, in Car Pooling routing, the next hop is determined from the neighbor head node, which is closest to the destination head node. Nevertheless, packets with a common next hop are aged and sent together in order to reduce overhead though they might have different destinations. The consequent sub-sections present the performance evaluation of SBD in terms of Energy Consumption, Reliability and Latency against Car Pooling, LEACH, GPSR and DD. #### 5.1.1 Energy Consumption

This experiment was conducted in a network of 180 nodes in a 90 m \(\times\) 90 m (8100 m\({}^{2}\)) field with a simulation time of 60 s. The data production and consumption rate per sector was varied between 0.1-15 packets per second. Figure 10a,b show the average energy consumption (joules) per node and total number of hop counts, respectively, as a function of packet rate per sector per sec. As shown in Figure 10a, SBD exhibits the lower energy consumption in all cases (low to high traffic rate). On the contrary, the energy consumption and total number of hop counts of DD are significantly higher than other methods and grows sharply due to its broadcasting. Figure 10b shows an interesting contrast.