More and more smart phones are equipped with the 3.5G and the Wi-Fi interfaces concurrently. Smart phones are able to share their 3.5G bandwidth for the other devices via the Wi-Fi connection. However, current technologies only allow one device to utilize the bandwidth provided from one Smart phone. In this paper, we propose Cooperative Stream Control Transmission Protocol (C-SCTP). C-SCTP enables one device to obtain the aggregated 3.5G bandwidth from multiple smart phones. C-SCTP adds the concept of transceiver to redirect packets. The simulation result shows that C-SCTP with four transceivers can have almost three times throughput than C-SCTP with one transceiver.