Integrated access and backhaul with reversed scheduling

1. A method for performing integrated access and backhaul, IAB, in a cellular telecommunications network that comprises a first IAB node and a second IAB node, the method being performed by the first IAB node, the method comprising:

scheduling, in a first phase, downstream backhaul data from the first IAB node to the second IAB node; and

receiving, in a third phase, from the second IAB node, upstream backhaul data as scheduled by the second IAB node;

wherein:

the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase, or

the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in a subsequent first phase, or

both the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase and the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in the subsequent first phase.

2. The method according to claim 1 , further comprising:

further scheduling, in the first phase, downlink user data from the first IAB node to a first user equipment in communication with the first IAB node.

3. The method according to claim 2 , further comprising:

receiving, in a second phase placed between the first phase and the third phase, uplink user data from the first user equipment, as scheduled by the first IAB node.

4. The method according to claim 2 , further comprising:

further scheduling, in the third phase, further downlink user data from the first IAB node to the first user equipment.

5. The method according to claim 1 , further comprising:

receiving, in a fourth phase placed after the third phase and before the subsequent first phase, further uplink user data from the first user equipment, as scheduled by the first IAB node.

6. The method according to claim 1 , wherein the first IAB node does not transmit uplink scheduling information to the second IAB node in the first phase.

7. The method according to claim 1 , wherein the downstream backhaul data is composed of symbols, and wherein the last one or more symbols of the downstream backhaul data of the first phase are blanked.

8. The method according to claim 1 , wherein the upstream backhaul data is composed of symbols, and wherein the last one or more symbols of the upstream backhaul data of the third phase are blanked.

9. A method for performing integrated access and backhaul, IAB, in a cellular telecommunications network that comprises a first IAB node and a second IAB node, the method being performed by the second IAB node, the method comprising:

receiving, in a first phase, from the first IAB node, downstream backhaul data as scheduled by the first IAB node; and

scheduling, in a third phase, upstream backhaul data from the second IAB node to the first IAB node;

wherein:

the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase, or

the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in a subsequent first phase, or

both the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase and the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in the subsequent first phase.

10. The method according to claim 9 , further comprising:

receiving, in a second phase placed between the first phase and the third phase, uplink user data from a second user equipment in communication with the second IAB node, as scheduled by the second IAB node.

11. The method according to claim 10 , further comprising:

further scheduling, in the third phase, downlink user data from the second IAB node to the second user equipment.

12. The method according to claim 10 , further comprising:

co-scheduling, in the third phase, together with the upstream backhaul data, downlink user data from the second IAB node to the second user equipment and/or to a third user equipment in communication with the second IAB node.

13. The method according to claim 9 , further comprising:

receiving, in a fourth phase placed after the third phase and before the subsequent first phase, further uplink user data from the second user equipment, as scheduled by the second IAB node.

14. The method according to claim 9 , wherein the second IAB node does not receive uplink scheduling information from the first IAB node in the first phase.

15. The method according to claim 9 , wherein the downstream backhaul data is composed of symbols, and wherein the last one or more symbols of the downstream backhaul data of the first phase are blanked.

16. The method according to claim 9 , wherein the upstream backhaul data is composed of symbols, and wherein the last one or more symbols of the upstream backhaul data of the third phase are blanked.

17. A first integrated access and backhaul, IAB, node for performing IAB in a cellular telecommunications network that comprises the first IAB node and a second IAB node, the first IAB node comprising processing circuitry, the processing circuitry causing the first IAB node to:

schedule, in a first phase, downstream backhaul data from the first IAB node to the second IAB node; and

receive, in a third phase, from the second IAB node, upstream backhaul data as scheduled by the second IAB node;

wherein:

the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase, or

the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in a subsequent first phase, or

both the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase and the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in the subsequent first phase.

18. A second integrated access and backhaul, IAB, node for performing IAB in a cellular telecommunications network that comprises a first IAB node and the second IAB node, the second IAB node comprising processing circuitry, the processing circuitry causing the second IAB node to:

receive, in a first phase, from the first IAB node, downstream backhaul data as scheduled by the first IAB node; and

schedule, in a third phase, upstream backhaul data from the second IAB node to the first IAB node wherein:

the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase, or

the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in a subsequent first phase, or

both the downstream backhaul data of the first phase is acknowledged or negatively acknowledged by the second IAB node in the third phase and the upstream backhaul data of the third phase is acknowledged or negatively acknowledged by the first IAB node in the subsequent first phase.