Fast Recovery from Hidden Node Collision for IEEE 802.15.4 LR-WPANs

The IEEE 802.15.4 specification does not include RTS/CTS mechanism to avoid the hidden/exposed node problem, for the consideration of constructing the low energy consumption networks. However, based on the modified CSMA/CA algorithm in LR-WPANs, the hidden node collisions will repeat up to aMaxframeRetries (default value is 3) times until the collided packets are discarded with a high probability. Therefore, a fast recovery mechanism is proposed in this paper to achieve the fast self-healing with negligible control overheads when the networks suffer the hidden node collisions. When the coordinator recognizes the hidden node collision occurs, it will issue a group polling ACK (PACK) to indicate the priority of the collided packets retransmission. Simulation results demonstrate that the proposed PACK mechanism is able to improve the network throughput and avoid the continuous hidden node collisions efficiently.