The existing intersession network coding mechanisms almost unanimously adopt “τ-interval-notification”, which is used to determine the coding opportunities, and its overhead has not been analyzed. In the current study, its communication overhead and its impacts on coding opportunity and throughput were analyzed, and an adaptive reception report sending mechanism called AR²SM (Adaptive Reception Reports Sending Mechanism) was proposed. In AR²SM, the interval of broadcasting reception reports is determined adaptively according to the traffic of local network, and the reception reports carry the packets overheard in the last 2 intervals. As a result, the size of reception report and the frequency of sending reception report were both reduced on the condition of guaranteeing the coding opportunity. According to the simulator results in network simulator, the proposed mechanism reduces the overhead of transmitting the reception reports, and achieves higher throughput than the “τ-interval-notification” mechanism.