Collision mitigation procedures for grant-less uplink multiple access

Abstract

A wireless transmit/receive unit (WTRU) may receive a grant-less (GL) transmission configuration that may include a first indication of a first set of resource blocks (RBs) for a first resource pool and a second indication of a second set of RBs for a second resource pool. The WTRU may select a subset of RBs in the first set, determine a subset of RBs in the second set based on the selected subset of RBs in the first set, and transmit UL data to the base station via the determined subset of RBs in the second set. The WTRU may receive a negative acknowledgement (NAK) with a third indication for at least one of a first transmission failure reason and a second transmission reason. The WTRU may adjust a backoff and determine a retransmission scheme based on the received third indication, and retransmit the UL data.

1 . A wireless transmit/receive unit (WTRU) for grant-less (GL) uplink (UL) transmissions, the WTRU comprising:
 a transceiver configured to receive one or more GL transmission configurations, including a first indication of a first set of resource blocks (RBs) for a first resource pool, and a second indication of a second set of RBs for a second resource pool;   a processor operatively coupled to the transceiver, the processor configured to select a subset of RBs in the first set;   the processor configured to determine a subset of RBs in the second set based on the selected subset of RBs in the first set;   the processor and the transceiver configured to transmit UL data, via the determined subset of RBs in the second set, to a base station;   the transceiver configured to receive a negative acknowledgement (NAK) with a third indication for at least one of a first transmission failure reason and a second transmission failure reason, wherein the first transmission failure reason is due to UL collision and the second transmission failure reason is due to UL low Signal-to-Noise Ratio (SNR);   the processor configured to adjust a backoff and determine a retransmission scheme based on the received third indication, wherein on a condition that the third indication is for the first transmission failure reason, the adjustment is increasing the backoff and the retransmission of the UL data is self-decodable; and   the processor and the transceiver configured to retransmit the UL data to the base station using the adjusted backoff and determined retransmission scheme.   
     
     
         2 . The WTRU of  claim 1 , wherein a total number of RBs in the first set is greater than a total number of RBs in the second set. 
     
     
         3 . The WTRU of  claim 1 , wherein the first resource pool is for at least one of WTRU identity (ID) information and control information for the WTRU, and the second resource pool is for data information. 
     
     
         4 . The WTRU of  claim 1 , wherein the subset of RBs in the first set are selected randomly. 
     
     
         5 . The WTRU of  claim 1 , wherein the subset of RBs in the first set are selected using a random access procedure and a backoff procedure. 
     
     
         6 . The WTRU of  claim 5 , wherein the random access procedure and the backoff procedure are based on one or more of a WTRU priority, a traffic type of UL data, and the received one or more GL transmission configurations. 
     
     
         7 - 8 . (canceled) 
     
     
         9 . The WTRU of  claim 1 , wherein on a condition that the third indication is for the second transmission failure reason, the adjustment is decreasing the backoff and the retransmission of the UL data uses incremental redundancy (IR)/Chase combining (CC) hybrid automatic repeat request (HARQ) combining. 
     
     
         10 . The WTRU of  claim 1 , wherein a time period between the reception of the GL transmission configuration and a transmission of the UL data is based on a backoff, and a time period between a transmission of the UL data and a retransmission of the UL data is based on a backoff. 
     
     
         11 . The WTRU of  claim 1 , wherein adjusting the backoff includes adjusting a backoff impact factor. 
     
     
         12 . The WTRU of  claim 1 , wherein the NAK is an RB based NAK. 
     
     
         13 . The WTRU of  claim 1 , further comprising:
 the processor and the transceiver configured to transmit at least one of WTRU ID information for the WTRU and UL control information for the WTRU, via the selected subset of RBs in the first set, to a base station.   
     
     
         14 . The WTRU of  claim 1 , wherein an RB group (RBG) includes one or more RBs. 
     
     
         15 . A method for use in a base station for grant-less (GL) uplink (UL) reception, the method comprising:
 transmitting one or more GL transmission configurations, including a first indication of a first set of resource blocks (RBs) for a first resource pool and a second indication of a second set of RBs for a second resource pool;   determining whether UL data has been received successfully, via a subset of RBs within the second set, from a first WTRU;   on a condition that the UL data has not been received successfully, determining, based on a first resource pool to second resource pool mapping, whether the first WTRU and at least a second WTRU have selected the subset of RBs of the second set;   on a condition that the first WTRU and at least the second WTRU have selected the subset of RBs of the second set, transmitting to the WTRU a negative acknowledgement (NAK) with a third indication for a first transmission failure reason and receiving from the WTRU a UL self-decodable data retransmission, wherein the first transmission failure reason is due to UL collision; and   on a condition that the first WTRU and at least the second WTRU have not selected the subset of RBs of the second set, transmitting to the WTRU a NAK with a third indication for a second transmission failure reason, wherein the second transmission failure reason is due to UL low Signal-to-Noise Ratio (SNR).   
     
     
         16 . The method of  claim 15 , wherein a total number of RBs in the first set is greater than a total number of RBs in the second set. 
     
     
         17 . The method of  claim 15 , wherein the first resource pool is for at least one of WTRU identity (ID) information and control information, and the second resource pool is for data information. 
     
     
         18 . (canceled) 
     
     
         19 . The method of  claim 15 , further comprising:
 receiving, via a first subset of RBs in the first set and a second subset of RBs in the first set, UL control information.   
     
     
         20 . The method of  claim 15 , further comprising:
 receiving, via a first subset of RBs in the first set, WTRU ID information for the first WTRU, and, via a second subset of RBs in the first set, WTRU ID information for the second WTRU.   
     
     
         21 . A method for use in a wireless transmit/receive unit (WTRU) for grant-less (GL) uplink (UL) transmissions, the method comprising:
 receiving one or more GL transmission configurations, including a first indication of a first set of resource blocks (RBs) for a first resource pool, and a second indication of a second set of RBs for a second resource pool;   selecting a subset of RBs in the first set;   determining a subset of RBs in the second set based on the selected subset of RBs in the first set;   transmitting UL data, via the determined subset of RBs in the second set, to a base station;   receiving a negative acknowledgement (NAK) with a third indication for at least one of a first transmission failure reason and a second transmission failure reason, wherein the first transmission failure reason is due to UL collision and the second transmission failure reason is due to UL low Signal-to-Noise Ratio (SNR);   adjusting a backoff and determining a retransmission scheme based on the received third indication, wherein on a condition that the third indication is for the first transmission failure reason, the adjustment is increasing the backoff and the retransmission of the UL data is self-decodable; and   retransmitting the UL data to the base station using the adjusted backoff and determined retransmission scheme.   
     
     
         22 . The method of  claim 21 , wherein a total number of RBs in the first set is greater than a total number of RBs in the second set. 
     
     
         23 . The method of  claim 21 , wherein the first resource pool is for at least one of WTRU identity (ID) information and control information for the WTRU, and the second resource pool is for data information.