Contention window size update for CAT.4 LBT for CBG based retransmission in NR systems operating on unlicensed spectrum
Systems, apparatuses, methods, and computer-readable media are provided for wireless communication using an unlicensed spectrum. An access point (AP) operating in the unlicensed spectrum includes a processor circuitry, a transmitter, and a receiver. The processor circuitry is configured to perform a listen before talk (LBT) procedure using an LBT parameter and a maximum channel occupancy time (MCOT) that is compatible with another wireless protocol using the unlicensed spectrum. The processor circuitry is configured to divide a transport block (TB) into a plurality of code block groups (CBGs) for transmission over the unlicensed spectrum. The transmitter is configured to transmit the plurality of CBGs to a destination, and a receiver is configured to receive hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmitted plurality of CBGs. The processor circuitry is further configured to determine a HARQ-ACK assessment for the TB based on the HARQ-ACK information corresponding to the transmitted plurality of CBGs, and adjust a contention window size based on the HARQ-ACK assessment for the TB.
1. An access point (AP), comprising:
processor circuitry configured to:
perform a listen before talk (LBT) procedure using an LBT parameter and a maximum channel occupancy time (MCOT) that is compatible with another wireless protocol using an unlicensed spectrum; and
divide a plurality of transport blocks (TBs) into respective first sets of code block groups (CBGs) for transmission over the unlicensed spectrum;
a transmitter configured to:
transmit the respective first sets of CBGs to a first destination;
transmit a second set of CBGs to a second destination;
a receiver configured to:
receive first hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmitted respective first sets of CBGs from the first destination; and
receive second HARQ-ACK information corresponding to the transmitted second set of CBGs from the second destination; and
the processor circuitry further configured to:
determine TB-based HARQ-ACK assessments for the plurality of TBs based on the first HARQ-ACK information corresponding to the transmitted respective first sets of CBGs;
determine CBG-based HARQ-ACK assessments for the transmitted second set of CBGs based on the second HARQ-ACK information corresponding to the transmitted second set of CBGs;
determine a first weighted average of a number of the TB-based HARQ-ACK assessments for the plurality of TBs being negative acknowledgements adjusted by a first weight and a number of the CBG-based HARQ-ACK assessments for the transmitted second set of CBGs being negative acknowledgements adjusted by a second weight, wherein a sum of the first weight and the second weight is 1, wherein the TB-based HARQ assessments being the negative acknowledgements is determined based on a percentage of negatively acknowledged CBGs out of the transmitted respective first sets of CBGs and the transmitted second set of CBGs exceeding a preconfigured percentage threshold, wherein the preconfigured percentage threshold requires more than one CBG being negatively acknowledged for the preconfigured percentage threshold to be satisfied;
determine a second weighted average of a number of TBs in the plurality of TBs adjusted by the first weight and a number of CBGs in the transmitted second set of CBGs adjusted by the second weight;
determine a ratio between the first weighted average and the second weighted average; and
adjust a contention window size based on the ratio.
2. The AP of claim 1 , wherein the other wireless protocol is Wi-Fi.
3. The AP of claim 1 , wherein the preconfigured percentage threshold is at least 80 percent.
4. The AP of claim 1 , wherein the processor circuitry is further configured to:
discard a TB-based HARQ-ACK assessment for adjusting the contention window size in response to not scheduling a negatively acknowledged CBG of a first set of CBGs.
5. The AP of claim 1 , wherein the processor circuitry is further configured to:
ignore a TB-based HARQ-ACK assessment for adjusting the contention window size based on a TB of the plurality of TBs being a punctured TB or based on at least one of a first set of CBGs being a punctured CBG.
6. A method for wireless communication using an unlicensed spectrum, comprising:
performing, at an access point (AP), a listen before talk (LBT) procedure using an LBT parameter and a maximum channel occupancy time (MCOT) that is compatible with another wireless protocol using the unlicensed spectrum;
dividing, at the AP, a plurality of transport blocks (TBs) into respective first sets of code block groups (CBGs) for transmission over the unlicensed spectrum;
transmitting, from the AP, the respective first sets of CBGs to a first destination;
transmitting, from the AP, a second set of CBGs to a second destination;
receiving, at the AP, first hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmitted respective first sets of CBGs from the first destination;
receiving, at the AP, second HARQ-ACK information corresponding to the transmitted second set of CBGs from the second destination;
determining, by the AP, TB-based HARQ-ACK assessments for the plurality of TBs based on the first HARQ-ACK information corresponding to the transmitted respective first sets of CBGs;
determining, by the AP, CBG-based HARQ-ACK assessments for the transmitted second set of CBGs based on the second HARQ-ACK information corresponding to the transmitted second set of CBGs;
determining a first weighted average of a number of the TB-based HARQ-ACK assessments for the plurality of TBs being negative acknowledgements adjusted by a first weight and a number of the CBG-based HARQ-ACK assessments for the transmitted second set of CBGs being negative acknowledgements adjusted by a second weight, wherein a sum of the first weight and the second weight is 1, wherein the TB-based HARQ assessments being the negative acknowledgement is determined based on a percentage of negatively acknowledged CBGs out of the transmitted respective first sets of CBGs and the transmitted second set of CBGs exceeding a preconfigured percentage threshold, wherein the preconfigured percentage threshold requires more than one CBG being negatively acknowledged for the preconfigured percentage threshold to be satisfied;
determining a second weighted average of a number of TBs in the plurality of TBs adjusted by the first weight and a number of CBGs in the transmitted second set of CBGs adjusted by the second weight;
determining a ratio between the first weighted average and the second weighted average; and
adjusting a contention window size based on the ratio.
7. The method of claim 6 , wherein the other wireless protocol is Wi-Fi.
8. The method of claim 6 , wherein the preconfigured percentage threshold is at least 80 percent.
9. The method of claim 6 , further comprising:
discarding, by the AP, a TB-based HARQ-ACK assessment for adjusting the contention window size in response to not scheduling a negatively acknowledged CBG of a first set of CBGs.
10. The method of claim 6 , further comprising:
ignoring, by the AP, a TB-based HARQ-ACK assessment for adjusting the contention window size based on a TB of the plurality of TBs being a punctured TB or based on at least one of a first set of CBGs being a punctured CBG.
11. A non-transitory computer-readable media (CRM) comprising computer instructions, where upon execution of the computer instructions by one or more processors of an access point (AP), causes the one or more processors to:
perform a listen before talk (LBT) procedure using an LBT parameter and a maximum channel occupancy time (MCOT) that is compatible with another wireless protocol using an unlicensed spectrum;
divide a plurality of transport blocks (TBs) into respective first sets of code block groups (CBGs) for transmission over the unlicensed spectrum;
transmit the respective first sets of CBGs to a first destination;
transmit a second set of CBGs to a second destination;
receive first hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmitted respective first sets of CBGs from the first destination;
receive second HARQ-ACK information corresponding to the transmitted second set of CBGs from the second destination;
determine TB-based HARQ-ACK assessments for the plurality of TBs based on the first HARQ-ACK information corresponding to the transmitted respective first sets of CBGs;
determine CBG-based HARQ-ACK assessments for the transmitted second set of CBGs based on the second HARQ-ACK information corresponding to the transmitted second set of CBGs;
determine a first weighted average of a number of the TB-based HARQ-ACK assessments for the plurality of TBs being negative acknowledgements adjusted by a first weight and a number of the CBG-based HARQ-ACK assessments for the transmitted second set of CBGs being negative acknowledgements adjusted by a second weight, wherein a sum of the first weight and the second weight is 1, wherein the TB-based HARQ assessments being the negative acknowledgements is determined based on a percentage of negatively acknowledged CBGs out of the transmitted respective first sets of CBGs and the transmitted second set of CBGs exceeding a preconfigured percentage threshold, wherein the preconfigured percentage threshold requires more than one CBG being negatively acknowledged for the preconfigured percentage threshold to be satisfied;
determine a second weighted average of a number of TBs in the plurality of TBs adjusted by the first weight and a number of CBGs in the transmitted second set of CBGs adjusted by the second weight;
determine a ratio between the first weighted average and the second weighted average; and
adjust a contention window size based on the ratio,
wherein the other wireless protocol is Wi-Fi.
12. The non-transitory CRM of claim 11 , wherein the preconfigured percentage threshold is at least 80 percent.
13. The non-transitory CRM of claim 11 , wherein, upon execution, the computer instructions further cause the one or more processors to discard a TB-based HARQ-ACK assessment for adjusting the contention window size in response to not scheduling a negatively acknowledged CBG of a first set of CBGs.
14. The non-transitory CRM of claim 11 , wherein, upon execution, the computer instructions further cause the one or more processors to ignore a TB-based HARQ-ACK assessment for adjusting the contention window size based on a TB of the plurality of TBs being a punctured TB or based on at least one of a first set of CBGs being a punctured CBG.