—The new IEEE 802.15.4e standard does not specify how the schedule of medium accesses followed by wireless sensors is built. That is why, we propose a distributed interference-aware joint channel and time slot assignment, called DiSCA, for a traffic-aware convergecast in multichannel wireless sensor networks (WSNs). Unlike most previous studies, we consider two cases of transmissions: without acknowledgment and with immediate acknowledgment. We provide the minimum bound on the number of time slots needed for a convergecast with a sink equipped with multiple radio interfaces. Simulations results show that DiSCA is close to the optimal in terms of the number of slots and outperforms TMCP.