Contention window adjustment mechanisms for FELAA systems
An apparatus of a Fifth Generation NodeB (gNB) to operate in a License Assisted Access (LAA) system configures a transmission initiation time interval contention window size (CWS) of N number of subframes between Category 4 Listen Before Talk (LBT) uplink (UL) transmissions by a user equipment (UE) operating in the LAA system, and a memory to store a value of N which can have a value 6 or greater or 10 or greater. An apparatus of a UE to operate in an LAA system decodes a configuration from the gNB of a transmission initiation time interval contention CWS of N number of subframes between Category 4 LBT UL transmissions in the LAA system. The CWS is increased to a next higher value when an UL grant or an autonomous UL (AUL) downlink feedback indicator (DFI) is not received before the expiration of a timer.
1. An apparatus of a user equipment (UE) to operate in a License Assisted Access (LAA) network, comprising:
radio frequency (RF) circuitry configured to communicate with the LAA network; and
one or more baseband processors communicatively coupled to the RF circuitry and configured to perform operations, comprising:
performing a Category 4 (Cat-4) Listen Before Talk (LBT) uplink (UL) transmission in the LAA network;
transmitting autonomous UL (AUL) uplink control information (UCI) to the LAA network, the AUL UCI comprising a joint indication indicating both a remaining number of subframes to be used by the CAT-4 LBT UL transmission and a length of a remaining maximum channel occupancy time (MCOT);
when neither an UL grant nor an AUL downlink feedback indicator (DFI) is received after N subframes have elapsed since a first subframe of the Cat-4 LBT uplink transmission, increasing a value of a contention window size (CWS) of all priority classes at the UE to a next higher value; and
when the UL grant is received and a new data indicator (NDI) bit for an active hybrid automatic repeat request (HARQ) processes of a hybrid automatic repeat request identity (HARQ_ID) reference (HARQ_ID_ref) is not toggled, updating the CWS and redrawing a counter value.
2. The apparatus of claim 1 , the operations further comprising:
receiving the UL grant or the AUL DFI after increasing the value of the CWS size for all priority classes to a next higher value, wherein the CWS is maintained at a current value.
3. The apparatus of claim 1 , the operations further comprising:
initiating LBT before expiration of a timer; and
updating the CWS and redrawing a counter value when: no UL grant or AUL DFI are received upon expiration of the timer or an AUL DFI is received and indicates negative acknowledgment (NACK) for the active HARQ processes of the HARQ_ID_ref wherein a transport block (TB) is not disabled.
4. The apparatus of claim 1 , the operations further comprising:
increasing the CWS to a next higher value for a subsequent AUL transmission when no UL grant or AUL DFI is received after a previous LBT UL transmission.
5. The apparatus of claim 1 , the operations further comprising:
redrawing a random counter value when the CWS is reset during an LBT UL transmission; and
when an UL grant or an autonomous UL (AUL) downlink feedback indicator (DFI) is received, maintaining the CWS at a same value.
6. One or more non-transitory machine readable media having instructions thereon that, when executed by an apparatus of a user equipment (UE) to operate in a License Assisted Access (LAA) network, result in:
performing Category 4 (Cat-4) Listen Before Talk (LBT) uplink (UL) transmission in the LAA system;
transmitting autonomous UL (AUL) uplink control information (UCI) to the LAA network, the AUL UCI comprising a joint indication indicating both a remaining number of subframes to be used by the CAT-4 LBT UL transmission and a length of a remaining maximum channel occupancy time (MCOT);
when neither an UL grant nor an autonomous UL (AUL) downlink feedback indicator (DFI) is received after N subframes have elapsed since a first subframe of the Cat-4 LBT uplink transmission, increasing a value of a contention window size (CWS) of all priority classes at the UE to a next higher value; and
when the UL grant is received and a new data indicator (NDI) bit for an active hybrid automatic repeat request (HARQ) processes of a hybrid automatic repeat request identity (HARQ_ID) reference (HARQ_ID_ref) is not toggled, updating the CWS and redrawing a counter value.
7. The one or more non-transitory machine readable media of claim 6 , wherein the instructions, when executed, further result in receiving the UL grant or the AUL DFI, after increasing the value of the CWS size for all priority classes to a next higher value, wherein the CWS is maintained at a current value.
8. The one or more non-transitory machine readable media of claim 6 , wherein the instructions, when executed, further result in starting an LBT UL transmission before expiration of a timer and to update the CWS and redrawing a counter value when: no UL grant or AUL DFI are received upon expiration of the timer or an AUL DFI is received and indicates negative acknowledgment (NACK) for the active HARQ processes of the HARQ_ID_ref wherein a transport block (TB) is not disabled.
9. The one or more non-transitory machine readable media of claim 6 , wherein the instructions, when executed, further result in increasing the CWS to a next higher value for a subsequent AUL transmission when no UL grant or AUL DFI is received after a previous LBT UL transmission.
10. The one or more non-transitory machine readable media of claim 6 , wherein the instructions, when executed, further result in redrawing a random counter value when the CWS is reset during an LBT UL transmission, and when an UL grant or an autonomous UL (AUL) downlink feedback indicator (DFI) is received, maintain the CWS at a same value.
11. A baseband processor configured to perform operations, comprising:
performing a Category 4 (Cat-4) Listen Before Talk (LBT) uplink (UL) transmission in the LAA system;
transmitting autonomous UL (AUL) uplink control information (UCI) to the LAA network, the AUL UCI comprising a joint indication indicating both a remaining number of subframes to be used by the CAT-4 LBT UL transmission and a length of a remaining maximum channel occupancy time (MCOT);
when neither an UL grant nor an autonomous UL (AUL) downlink feedback indicator (DFI) is received after N subframes have elapsed since a first subframe of the Cat-4 LBT uplink transmission, increasing a value of a contention window size (CWS) of all priority classes to a next higher value; and
when the UL grant is received and a new data indicator (NDI) bit for an active hybrid automatic repeat request (HARQ) processes of a hybrid automatic repeat request identity (HARQ_ID) reference (HARQ_ID_ref) is not toggled, updating the CWS.
12. The baseband processor of claim 11 , wherein the operations further comprise:
receiving the UL grant or the AUL DFI, after increasing the value of the CWS size for all priority classes to a next higher value, wherein the CWS is maintained at a current value.
13. The baseband processor of claim 11 , wherein the operations further comprise:
starting an LBT before expiration of a timer and to update the CWS and redraw a counter value when: no UL grant or AUL DFI are received upon expiration of the timer or an AUL DFI is received and indicates negative acknowledgment (NACK) for the active HARQ processes of the HARQ_ID_ref wherein a transport block (TB) is not disabled.
14. The baseband processor of claim 11 , wherein the operations further comprise:
increasing the CWS to a next higher value for a subsequent AUL transmission when no UL grant or AUL DFI is received after a previous LBT UL transmission.