CORP: Cooperative rateless code protocol for vehicular content dissemination

Data dissemination in vehicular networks has been a challenge due to unpredictable network dynamics and channel unreliability. In fact, conventional approaches that rely on TCP or UDP do not perform well and cannot consistently guarantee reliable communications. A potential solution to these problems involves using erasure-correcting codes to make UDP transmissions reliable. However, it is also important to note that, due to vehicular mobility and road obstacles, connections among nodes can be as short as a few seconds. Therefore, in a communication between two nodes, the delay between node discovery and data exchange must be minimized. In this paper we present CORP, a Cooperative Rateless Protocol that exploits the reliability of the rateless coding approach while performing fast and efficient dissemination through cooperating nodes within the network. The use of rateless codes and unicast connections places minimal constraints on the delay between node discovery and data transmission, thus simplifying and rendering feasible the content reliable download even in a highly dynamic scenario. Results from simulations reveal that performance improves as more and more nodes cooperate. In sum, CORP yields important improvements in terms of speed of dissemination when compared to traditional approaches such as TCP.