## 1 Introduction  
The Internet of Things (IoT) [1] is not only an important part of the new generation of information technology but also an important stage of development in the \"information\" era. Sensor technology is a key technology in the IoT. A great deal of real-time data generated by sensors need to be scheduled [2] and securely transmitted [3] to the sink nodes through wireless or wired networks. Distributed sensors are deployed in different areas, and the data are harvested in distributed sink nodes. These data need to be transmitted to one or more certain destinations through heterogeneous networks. The data transmissions among the wireless and wired networks face the high latency, high packet loss rate and other problems. In IoT, it is important to improve transmission efficiency and reduce packet loss for these distributed data. The quality of information transmission between sensors is critical, and high-quality data transmission among sensors or sink nodes are necessary in wireless sensor networks (WSN) [4] and IoT. CyberGIS [5] deals with location based data on the IoT, which could solve the location based services. The sensors' data harvested from different areas are stored in different locations. The Fog computing [6] can solve the sensing data on edge networks to enhance the data transmission efficiencies. Software defined network (SDN) based sensor network [7] can also balance the data transfer congestions in the IoT environments by the centralized scheduling. In these scenarios, the techniques of methods all require high speed and high performance wired or wireless data transmissions. IoTs and the fifth generation (5G) [8] visions aim at providing massive connectivity, high access speed, low latency, and quality of service (QoS). Various types of networks and incompatible networks also bring challenges to the transmission of heterogeneous networks [9]. In order to improve the transmission speed of wireless networks, parallel transmission technologies on different layers are proposed. For instance, Multiple-input multiple-output (MIMO) and channel assignment algorithms [10] on the media access control address (MAC) layer; multi-path routing algorithms [11] on the network layer; SCTP and multipath TCP (MTCP) [12] on the transport layer; data separation methods on the application or the higher layer; and cross layer [13; 14] designs for multipath transmission. In addition, network coding methods [15; 16] are used to leverage and balance the data transmission traffic. [PERSON] et al. [17] propose a new mechanism called the TCP/NC that incorporates network coding into TCP with only minor changes to the protocol stack, thereby allowing incremental deployment. At the same time, the connection establishment process of SCTP is more complicated. In [18], we proposed a dynamic multipath switching method for SCTP to improve the efficiency of information transmission in heterogeneous networks and reduce packet loss rate. The packet loss rate of each transmission link is used to predict the transmission quality of each link and dynamically adjust the main link in advance to improve the efficiency of information transmission. In this paper, we propose a new scheme that could improve the transmission quality by the switch of TCP and SCTP. Compared to our previous work, we compared the average throughput, real-time throughput, and stability between TCP and SCTP in detail. This work proposes the combined TCP-SCTP and also proposes the path selection methods based on the sender's buffer. MTCP [19] is used in multimedia and collaborative computing [20]. SCTP has the multi-host and multi-flow features. The multi-host feature can fully use the network link resources and improve the transmission efficiency. Multi-flow features can process multiple request information parallel to control information, and therefore data can also be separated and allocated to different streams. To some extent, it improves the response efficiency and the transmission efficiency and improves the utilization rate of network resources.