Method and device for relay transmission

A second node for wireless communications, comprising:

• a second receiver, receiving a first physical-layer signaling via an air interface, detecting a first MAC PDU via an air interface, the first MAC PDU comprising a first MAC header and a first MAC SDU;
• and
• a second transmitter, transmitting a first HARQ-ACK on a first channel in a first channel set, or, dropping transmitting a first HARQ-ACK;
• characterized in that the first channel set comprises Q channel(s), Q being a non-negative integer;
• whether the first HARQ-ACK is transmitted is related to Q, the first channel set is reserved for the first HARQ-ACK, and the first HARQ-ACK indicates whether the first MAC PDU is correctly decoded;
• the first physical-layer signaling comprises scheduling information of the first MAC PDU;
• whether a number of continuous HARQ DTXs reaches a first threshold is used to determine Q;
• the first MAC SDU is transmitted through a first radio bearer, and the first radio bearer is unrelated to whether the number of the continuous HARQ DTXs reaches the first threshold.

A third node for wireless communications, comprising:

• a third receiver, receiving a first physical-layer signaling via an air interface, detecting a first MAC PDU via an air interface, the first MAC PDU comprising a first MAC header and a first MAC SDU;
• monitoring a first HARQ-ACK on a first channel in a first channel set;
• or, dropping monitoring a first HARQ-ACK;
• and
• a third transmitter, transmitting a first HARQ-ACK on a channel in a first channel set;
• characterized in that the first channel set comprises Q channel(s), Q being a non-negative integer;
• whether the first HARQ-ACK is monitored is related to Q, the first channel set is reserved for the first HARQ-ACK, and the first HARQ-ACK indicates whether the first MAC PDU is correctly decoded;
• the first physical-layer signaling comprises scheduling information of the first MAC PDU;
• whether a number of continuous HARQ DTXs reaches a first threshold is used to determine Q;
• the first MAC SDU is transmitted through a first radio bearer, and the first radio bearer is unrelated to whether the number of the continuous HARQ DTXs reaches the first threshold.

A method in a first node for wireless communications, comprising:

• transmitting a first physical-layer signaling and a first MAC PDU via an air interface, the first MAC PDU comprising a first MAC header and a first MAC SDU;
• and
• monitoring a first HARQ-ACK on each channel in a first channel set, the first HARQ-ACK indicating whether the first MAC PDU is correctly decoded;
• characterized in that the first physical-layer signaling comprises scheduling information of the first MAC PDU;
• the first channel set comprises Q channel(s), Q being a non-negative integer;
• whether a number of continuous HARQ DTXs reaches a first threshold is used to determine Q;
• the first MAC SDU is transmitted through a first radio bearer, and the first radio bearer is unrelated to whether the number of the continuous HARQ DTXs reaches the first threshold.