## 2 Related Works
The variations of _increase_, _decrease_ or _oscillation_ of the metrics are with respect to the values of these present in the steady state. It is observed that constant and deceptive jammers in general cause a greater decrease in the PDR and a greater increase in the negative value of the RSSI. As there are fewer packets received and less signal strength, the search for routes with better quality becomes greater, consuming more time and energy in processing the information for forwarding. The relation between the above metrics are used in many ways to detect and mitigate jamming attacks. If, for example, the routing table of a node increases considerably, its processor must work more and consume more energy, having less time to react to any contingency. Resilience is the ability to recover in a short time from a communication failure, reducing the transmission delays by minimizing the number of hops. A resilient WSN maintains good RSSI levels [41]. RSSI values are in dBm. A level close to 0 dBm represents a good signal level, while a signal level close to \(-110\) dBm indicates that the signal is very poor, which may be due to environmental conditions, the presence of jamming, low-density network nodes, etc. [12]. On the other hand, a good PDR measurement (close to 100%) allows us to take better advantage of the processor memory, which will heat less by not having to process more information unnecessarily [14]. The released heat comes from the electrical energy and impacts less battery life. In the detection of the existence of jamming, a normal value of one can be taken for the SNR metric, since this parameter is the relationship between the signal to be communicated with the noise signal. A less than one value would mean that the noise is greater than the transmitted signal and would make it opaque [20]. Closely linked to the SNR is the BER metric [30], which gets a high value only when the SNR is low [42]. When the noise is greater than the transmitted signal, the SNR metric is less than one, and this has an exponential impact on Bit Error Rate (BER) metric. The reduction of retransmissions, as well as hops, is important in a network to ensure that a greater number of packets reach \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Detection Technique** & **Metrics** & **Description** \\ \hline Cross-layer system [37] & Frequency-hopping pattern & Detection is done when the transmitter uses additional test patterns during its transmission. \\ \hline Control channel attack prevention [38] & Hamming distance & Is a cross layer system that implements part of the system network module and part in the driver. \\ \hline Game theoretic modeling [39; 40] & Request to send (RTS), network allocator value & Cluster retransmission of data using CSMA/CD (collision detection) and a network allocator value. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Type of jamming** & **PDR** & **RSSI** & **Energy** & **BPR** & **SNR** & **BER** \\ \hline Constant & \(--\) & \(++\) & \(++\) & \(-\) & \(\leq\)1 & \(-\) \\ \hline Deceptive & \(--\) & \(++\) & \(++\) & \(+\) & \(\leq\)1 & \(-\) \\ \hline Random & \(-\) & \(+\) & \(+\) & \(+\) & \(\leq\)1 & \(+-\) \\ \hline Reactive & \(-\) & \(+\) & \(+\) & \(+\) & \(\leq\)1 & \(+-\) \\ \hline \hline \end{tabular}  
* Increases = “\(+\)”, increases a lot = “\(++\)”, decreases = “\(-\)”, decreases a lot = “\(--\)”, oscillates = “\(+\)\(--\)”.  
\end{table} 
Table 3: Jamming _symptons._their destination. Due to the above, the BPR metric can complement the SNR and the BER in the detection of jamming [20]. A strong signal is less likely to have errors than a weak one. If an error increases with SNR, it is due to noise, but this noise could be due to unintended interference from, for example, motors and actuator on a machine in a factory.