Retransmission techniques are disclosed. These techniques may be used in networks employing contention-based access schemes, such as CSMA. For instance, a device may receive a corrupted packet from a transmitting device, and determine a cause of the corruption. When the determined cause of the corruption is an in-network packet collision, the device allows the transmitting device to send a retransmission of the packet in accordance with a contention-based access scheme. However, when the determined cause of the corruption is other than an in-network packet collision, the device provides retransmission assistance to the transmitting device. This retransmission assistance may include a channel reservation for a retransmission, and/or one or more link adaptation suggestions for the transmitting device.