## 2 Related Work  
In this section, we briefly summarize the existing node-disjoint [7; 8]/radio-disjoint [10; 11] multipath routing protocols. NDRECT [7] is a node-disjoint multipath scheme to support real-time traffic, which consists of two stages of the discovery phase and the path establishment phase. In the discovery phase, the source node floods the route request (RREQ) message throughout the network to discover the sink node. In this process, intermediate nodes categorize neighboring nodes through RREQ messages received from different neighbors as predecessors, same level, and successors, and are tagged with different values depending on the number of RREQ messages received from the different predecessors. The RREQ message contains information for route selection, and to mitigate flooding overhead, the intermediate node aggregates the RREQ message received from the neighboring node and forwards only one RREQ message. Through the above process, the sink node which received the RREQ message can select the most appropriate peers and return a route reply (RREP) message to the source node. The RREP message includes necessary information to select the next node to reach the source node. This RREP message, which arrives at the source node, containsinformation on the nodes that it has been through. Finally, the source node could transmit a packet through a node-disjoint multipath to the sink by exploiting this information. FD-AOMDV [8] is a multipath routing protocol which exploits a node-disjoint approach to find alternate paths between the source and sink nodes. To construct a multipath, the source node broadcasts aREQ message to all nodes within the communication range. Each intermediate node which receives the RREQ message appends the source node to the routing table and retransmits it to its neighboring nodes. When the RREQ message reaches the destination node or an intermediate node which has a route to the sink node, the node responds with the RREP message to the source node. Once the source node receives the RREP message, it can transmit data packets to the sink node exploiting the information in the routing table. In the transmission process, the source node transmits the data packet through the main path. However, if the main path becomes unavailable due to failure or other reasons, it transmits the data packet through the alternate path. IMCMRP [10] was proposed to minimize path interference exploiting four phases: neighbor node identification, cluster head selection, route establishment, and data transmission. In the neighbor identification phase, nearby nodes within the communication range are identified and the transmission cost to neighboring nodes is estimated to establish a path to the sink node. Next, cluster heads are selected based on residual energy and interference degree. When an event occurs, the RREQ message is exploited to request construction of a path to the sink node, and the sink node responds with the RREP message. The source node then completes the multipath construction by sending a confirmation acknowledgment (CACK) message in response to the RREP. The data are divided and sent to the sink node exploiting medium-quality paths for low data rates and high-quality paths for high data rates. After successful data transmission, the sink node notifies the source node, and the source node releases the participating members and the cluster head using the release acknowledgment (RACK) message. RMR [11] is a radio-disjoint multipath scheme which aims to improve the end-to-end transmission success ratio exploiting multipath. It could increase the lifetime of the network by exploiting the gap called the guard band between the paths reserved for path disjoint. The source node calculates the number of paths based on the required end-to-end transmission success ratio and single-hop transmission success ratio according to the user or applications.