## 3 Opportunistic Transmission Scheme for Integrated UAV-ICV Networks Enabled by Node Cooperation
### Information Flooding  
When the source node (UAV or ICV) generates information, it creates several message copies and forwards them to neighboring nodes that have not yet received this copy. Dur  
Figure 2: A flow chart of the proposed solution.  
ing the forwarding process, the proposed opportunistic transmission scheme determines whether to transmit the message copy based on the encounter probability analysis model derived in Section 2.2 and then updates the encounter probabilities of the communication nodes. As discussed in [7], this paper uses [PERSON]'s theorem to establish the node transfer update equation, which is given by  
\[P_{\text{Transfer}} = \sum P(\,X|M,\ k_{1},\ k_{2},\ H_{\text{max}})\] \[\times P(\,X|M,\ k_{1},\ k_{2},\ H_{\text{max}}),\]  
where \(P_{\text{Transfer}}\) is the updated encounter probability, \(\sum P(\,X|M,\ k_{1},\ k_{2},\ H_{\text{max}})\) is the likelihood function, and \(P(\,X|M,\ k_{1},\ k_{2},\ H_{\text{max}})\) is the prior probability. In addition, in (12), \(M\) represents the number of communication nodes involved in the communication, \(M\leq N+R\); \(k_{1}\) and \(k_{2}\) are the number of type II and type III nodes participating in relay transmission in integrated UAV-ICV networks, respectively. It should be noted that for ICVs, the number of type I nodes is \(N-k_{1}-k_{2}\), and all \(R\) UAVs are type I nodes. After the message copy reaches the relay communication node, \(P(\,X|M,\ k_{1},\ k_{2},\ H_{\text{max}})\) can be further calculated as (13) based on the node type of relay nodes and the encounter probability analysis model. We have  
\[P(\,X|M,\ k_{1},\ k_{2},\ H_{\text{max}}) \tag{13}\] \[= \left\{\begin{array}{ll}[(N+R-k_{1}-k_{2})-(M-k_{1}-k_{2})] \lambda_{ij}P_{\text{suc}}(i,\ j),&\text{if }X=(M+1,\ k_{1},\ k_{2},\ H_{\text{max}}+1),\\ (K_{1}+K_{2}-k_{1}-k_{2})\lambda_{ij}P_{\text{suc}}(i,\ j)\times\Big{[}1-P_{ \text{drop}}(j)\Big{]},&\text{elseif }X=(M+1,\ k_{1},\ k_{2},\ H_{\text{max}}),\\ (K_{1}+K_{2}-k_{1}-k_{2})\lambda_{ij}P_{\text{suc}}(i,\ j)P_{\text{drop}}(j),& \text{elseif }X=(M,\ k_{1},\ k_{2},\ H_{\text{max}}),\\ \lambda_{ij}P_{\text{suc}}(i,\ j),&\text{else}.\end{array}\right.\]  
where \(K_{1}\) and \(K_{2}\) are the number of type II and type III nodes in integrated UAV-ICV networks, respectively; \(X\) denotes the state of the transition model; \(D\) indicates that the relay node is the destination node, meaning the message copy will no longer be forwarded.  
In addition, the forwarding conditions of message copies are related to the cooperation threshold of the communication nodes in integrated UAV-ICV networks and the type of message copies. These conditions are mainly divided into the following two cases:  
* Case 1: When the next-hop node is a type II communication node, the transfer probability \(P_{\text{Transfer}}\) of the communication node is compared with the cooperation threshold \(P_{\text{Transfer}\text{II}}\) of the type II communication node. If \(P_{\text{Transfer}\text{II}}\leq P_{\text{Transfer}}\), the message copy is transmitted. If \(P_{\text{Transfer}\text{II}}>P_{\text{Transfer}}\), the message copy is not transmitted.
* Case 2: When the next-hop node is a type III communication node, the message copy type is first evaluated, with \(M_{\text{Mes.type}}\) defined as the message type. If \(M_{\text{Mes.type}}=1\), it indicates that the message copy is related to the relay node, and the message copy is transmitted. If \(M_{\text{Mes.type}}=0\), it indicates that the message is not related to the relay node, and the cooperation threshold \(P_{\text{Transfer}\text{III}}\) must be compared. If \(P_{\text{Transfer}\text{III}}\leq P_{\text{Transfer}}\), the message copy is transmitted. If \(P_{\text{Transfer}\text{III}}>P_{\text{Transfer}}\), the message copy is not transmitted.