## 2 Literature Review
### MWSN Architecture
#### 2.4.1 Distributed MWSN Architecture  
In the actual situation of oilfield development, we can use network communication and mobile agent data fusion technology to create a dynamic multimedia WSN system. It carries monitoring data and controls the transmission of multimedia information. Communication energy consumption accounts for a large part of the energy consumption of the entire sensor network due to the large amount of multimedia information. The MWSN has multi-level, multi sink, distributed sensor nodes of a variety of network systems [26]. Moreover, it is necessary to classify monitoring data from different nodes, all of which need many data transfers. To reduce the frequency of communication, limiting the scope of data communication to local clusters is a better solution. Due to their proximity, nodes in the same cluster often receive identical information. Temperature sensors in adjacent regions often record the same temperature. Avoiding duplication, cluster nodes extract relevant useful information locally, use this information, and communicate it to each other through a broadcasting system [27]. Data replication technology can improve data transmission rates, which can help data recovery [28] quickly. MWSN often have poor connectivity between the mobile sensors. If nodes lose connection and data must send to the next hop node, they store the data temporarily until the connection is re-established or the node finds a better path. Therefore, the sensor nodes need to have a certain storage ability. Sensor networks have two types of calculation models for collaborative information processing. Key distinctions are the type of payload (code with processing code or data) and the location of integration (locally or in the processing center). In the traditional client/server computing (C/S) model [16], all sensor nodes send data directly to the processing center as shown in Figure 7a. In applications with substantial amounts of data, sensor nodes usually only compress the data collected and transfer it directly to the processing center for processing. On larger scale, hierarchical data processing solves transfer problems step by step as shown in Figure 7b. These methods are not efficient enough in the case of wireless network with limited bandwidth, where the amount of data is increasing, and the energy of each sensor node is very limited. Although client/server based distributed computing is popular, it is not suitable for development of sensor networks. Sensor networks have unique independent features in combination with mobility. They have very limited resources and large numbers of sensor nodes. Sensor nodes and communication  
Figure 6: Block diagram of the main node of the scheduling and control center. links are prone to failure, and have abnormal dynamic characteristics. When their energy is exhausted, existing sensor nodes will stop working, and the network must use other mobile sensor nodes. In the mobile agent computing model, the transfer unit is the mobile agent itself and the final data fused at each sensor node. This model has the following obvious advantages: scalability, reliability, multi-task adaptability, energy-awareness, and accuracy of fusion. With mobile agents, increasing numbers of sensor nodes do not affect performance. Mobile agents set up connections and return results. Designers can give them a variety of software tasks to expand the network functions. Information gain and energy restrictions dynamically determine the path of mobile agents. The accuracy of the fusion results increases with the number of agents. Agents can either visit all nodes on the migration path, or they can avoid unnecessary migration. The former increases accuracy, the latter is more efficient when the amount of data is much larger than the software code. [PERSON] and [PERSON] [29] propose a data centric energy efficient routing protocol by using wireless local area network technology, while [PERSON] et al. propose a multi hop sensor network based on clustering of self-organizing routing mechanisms [30].