# A Novel Anti-Jamming Decision-Making Algorithm Based on Knowledge Graph Technology
## 4 Decision-Making Algorithm Based on Anti-Jamming Knowledge Graph  
### Decision-Making Algorithm  
#### 4.1.1 Algorithm Description  
The anti-jamming knowledge graph can be regarded as a combination of several triples. Each node in the graph represents an entity of communication anti-jamming knowledge, and the edge represents the relationship between two nodes. If a triple is regarded as a one-way relationship, the initial node is called the head node. The head node points to the tail node in the triple through the relation edge. The search process of anti-jamming knowledge graph is to utilize two entities in a triplet relation to search the other entities. In this paper, the communication anti-jamming decision-making algorithm based on knowledge graph is divided into two steps: strategy extraction and strategy fusion. Strategy extraction is the process of obtaining the anti-jamming strategies corresponding to the jamming pattern by searching the anti-jamming knowledge graph. Specifically, we take the jamming patterns as the head node and take the anti-jamming relation (i.e., head node and relational edge) to search the anti-jamming strategies (i.e., tail nodes) when the jamming patterns are known. However, if the jamming patterns are unknown, we first obtain the time-frequency domain features of the unknown jamming patterns by the time-frequency domain feature extraction method. Then, we take the time-frequency domain features as the head node and the anti-jamming relation as the relational edge, search the tail node, and obtain the anti-jamming strategies corresponding to the time-frequency domain features. Finally, we obtain the corresponding parameters of each anti-jamming strategy by the communication parameter decision method described in Section 3.2. Each strategy-parameter set can be expressed as \((a_{i},\mathbf{p}_{i})\), where \(a_{i}\) represents an anti-jamming strategy, and \(\mathbf{p}_{i}=\{p_{i1},p_{i2},\ldots,p_{in}\}\) represents the corresponding decision-making parameters of the anti-jamming strategy. Multiple anti-jamming strategies may be obtained in the search process, and strategy fusion is to integrate the possible anti-jamming strategies after strategy extraction to obtain the optimal strategy. Firstly, taking the intersection of the anti-jamming strategies in the same domain and the union set of anti-jamming strategies in different domains, we obtain the anti-jamming strategy set \((\mathbf{A},\mathbf{P})\) of preliminary fusion, where \(\mathbf{A}=\{a_{1},a_{2},\ldots a_{i}\}\) represents the strategy set and \(\mathbf{P}=\{\mathbf{p}_{1},\mathbf{p}_{2},\ldots\mathbf{p}_{n}\}\) represents the set of each strategy parameter set. Then, we further optimize the strategy set after strategy fusion according to the communication requirements and select the strategy with the lowest communication cost which can ensure the communication transmission to improve the communication transmission efficiency. Finally, the anti-jamming decision-making is formed. Assuming that the extracted anti-jamming strategy includes the frequency domain and the power domain, when the purpose of the anti-jamming can be achieved by adopting only the frequency domain strategy, the communication cost is lower at the same time. In this regard, the power domain strategy can be discarded, and the frequency domain strategy can be the final optimal strategy. The specific process of the decision-making algorithm is shown in Algorithm 1. It is assumed that we can extract the characteristics of the jamming signal at the current moment and search for the strategy in each communication time slot. After initialization, first obtain the information of the jamming signal (line 2). According to the information, determine whether the jamming pattern is known (line 3). Directly search for strategies in the anti-jamming knowledge graph for known jamming patterns (line 4). To unknown jamming patterns, the jamming period should be divided into multiple time slots.