## 4 Local Transmission Control: Redundancy-Based Transmission
### Local Route Establishment
#### 4.1.2 Local Route Reply
### Local Route Reconfiguration Process

If a node detects a link failure but is unable to send data to a neighbor node on the primary path or redundant path, the node uses a failure-notification (FN) packet to send route failure information to the upstream node. The FN packet includes information about the failure-detection node, whether the failure-detection node is located on the primary path, and the intermediate nodes through which the failure-notification packet is propagated. Every node that receives an FN packet performs Algorithm 7. ```
1:Case 1: If the receiving node is on the primary path and the FN packet originates from a node on the primary path, the receiving node uses an alternate redundant path. If there is no valid redundant path, an FN packet is sent to the upstream node. 2:Case 2: If the receiving node is on the primary path and the FN packet originates from a node on the redundant path, the receiving node deletes all information about the failed redundant path. If there is valid alternate redundant path, the receiving node uses that. Otherwise, an FN packet is sent to the upstream node. 3:Case 3: If the receiving node is on the redundant path, an FN packet is sent to the upstream node. ```

**Algorithm 7** Local route reconfiguration process. ## 5 Performance Evaluation

In this work, we implemented the proposed control algorithm and compared schemes using MATLAB-based discrete-time event simulation toolboxes: WLAN toolbox, Communication toolbox, DSP System toolbox, and Signal Processing toolbox [16]. We assumed a low-power mobile terminal based WLAN adhoc networks. The nodes used the IEEE 802.11 radio and MAC model. Each source sent data packets at a constant rate of 4 packets/s. Each packet size was 512 bytes. This simulation modeled a network of uniformly deployed mobile hosts within a given area. We executed each simulation using 15 sessions with randomly selected sources and destinations for 1000 s. The simulation parameters are summarized in Table 1.

In this simulation, the parameters related to the wireless channel and mobility were used according to the standard specification documents of the wireless communication and networking system. However, the parameters related to the proposed control algorithm did not have a standard model: hub mobility threshold (\(\delta\)), relative mobility speed threshold (\(\gamma\)), relative mobility angle threshold \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Assumption** \\ \hline Node deployment & Uniform \\ Node density & \(1/2500\) (m\({}^{2}\)) \\ Minimum node distance & \(50\) (m) \\ Node transmit power & \(20\) (dBmW) \\ Path-loss & \(140.7+36.7\log_{10}(d(\text{km}))\) (dB) \\ Fading & Slow Rayleigh fading \\ Node mobility & Random Waypoint \\ Traffic model & Full Buffer \\ Hub mobility threshold (\(\delta\)) & \(0.2*\)average-mobility-speed \\ Relative mobility speed threshold (\(\gamma\)) & inf \\ Relative mobility angle threshold (\(\theta\)) & \(\pi\), \(\pi/2\) \\ DCT & \(300\)(ms) \\ Probability condition (\(\bar{\gamma}\)) & \(0.9\) \\ Maximum redundancy (\(UB\)) & \(4\) \\ Maximal path length (\(m\)) & inf \\ Delay proportional coefficient (\(w\)) & \(1\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: System-level simulation parameters. (\(\theta\)), DCT, probability condition (\(\xi\)), maximum redundancy (\(UB\)), maximal path length (\(m\)), and delay proportional coefficient (\(w\)). In fact, these may be set differently according to a service to be actually applied. In this work, we did not assume any specific application services. Instead, we set the parameters heuristically to fully reflect the characteristics of the proposed algorithm. In this section, we compare the following schemes. * Proposed (\(\alpha\)) denotes the proposed control when \(\theta\) is \(\alpha\) in Equation (17). * SOUR denotes a source oriented on-demand transmission control such as a dynamic source-routing control [17].