Multi-cell scheduling with reduced control overhead

Abstract

Methods and apparatuses for multi-cell scheduling with reduced control overhead. A method for receiving physical downlink control channels (PDCCHs) includes receiving information for a first group of N1 cells and for a second group of N2 cells, determining a total number of PDCCH receptions in a slot on a scheduling cell based on N1 and on a ratio of N2 over M, and receiving a number of PDCCHs in the slot on the scheduling cell that is not larger than the total number. A PDCCH provides a downlink control information (DCI) format. The DCI format schedules one of: a physical downlink shared channel (PDSCH) reception, or a physical uplink shared channel (PUSCH) transmission, on one cell from the first group of N1 cells, or PDSCH receptions, or PUSCH transmissions, on a number of cells up to a maximum of M cells from the second group of N2 cells.

What is claimed is: 
     
         1 . A method for receiving physical downlink control channels (PDCCHs), the method comprising:
 receiving information for a first group of N1 cells and for a second group of N2 cells, wherein:
 a PDCCH provides a downlink control information (DCI) format, and 
 the DCI format schedules one of:
 a physical downlink shared channel (PDSCH) reception, or a physical uplink shared channel (PUSCH) transmission, on one cell from the first group of N1 cells, or 
 PDSCH receptions, or PUSCH transmissions, on a number of cells up to a maximum of M cells from the second group of N2 cells, wherein M is larger than one; 
 
   determining a total number of PDCCH receptions in a slot on a scheduling cell based on N1 and on a ratio of N2 over M; and   receiving a number of PDCCHs in the slot on the scheduling cell that is not larger than the total number.   
     
     
         2 . The method of  claim 1 , wherein:
 the DCI format schedules the PDSCH receptions, or the PUSCH transmissions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   the DCI format includes a field indicating the number of cells.   
     
     
         3 . The method of  claim 1 , wherein:
 the DCI format schedules the PDSCH receptions, or the PUSCH transmissions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   a size of the DCI format is same for any value of the number of cells.   
     
     
         4 . The method of  claim 1 , wherein:
 the DCI format includes a counter downlink assignment index (DAI) field with a first maximum number of bits, when the DCI format schedules the PDSCH reception, or the PUSCH transmission, on the one cell from the first group of N1 cells,   the DCI format includes the counter DAI field with a second maximum number of bits, when the DCI format schedules the PDSCH receptions, or the PUSCH transmissions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   the second maximum number of bits is larger than the first maximum number of bits.   
     
     
         5 . The method of  claim 1 , further comprising:
 receiving a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules transmissions of first and second PUSCHs on respective first and second cells from the second group of N2 cells, 
 the first and second cells are in a same frequency band, and 
 the second DCI format includes a transmission power control (TPC) command that provides one value; 
   determining first and second powers for transmission of the first and second PUSCHs, respectively, based on the one value; and   transmitting the first and second PUSCHs using the first and second powers, respectively.   
     
     
         6 . The method of  claim 1 , further comprising:
 receiving a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules transmissions of first and second PUSCHs on respective first and second cells from the second group of N2 cells, 
 the first cell has a smaller index that the second cell, and 
 the second DCI format includes a downlink assignment index (DAI) field; 
   determining hybrid automatic repeat request acknowledgement (HARQ-ACK) information based on a value of the DAI field; and   transmitting the first and second PUSCHs on the first and second cells, respectively, wherein the HARQ-ACK information is included only in the first PUSCH.   
     
     
         7 . The method of  claim 1 , further comprising:
 receiving a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules receptions of first and second PDSCHs on respective first and second cells from the second group of N2 cells, and 
 the second DCI format includes a frequency domain resource allocation (FDRA) field that indicates resource block groups (RBGs), wherein an RBG includes:
 a first number of resource blocks (RBs) on the first cell, and 
 a second number of RBs on the second cell; and 
 
   receiving the first and second PDSCHs over the indicated RBGs.   
     
     
         8 . A user equipment (UE), comprising:
 a transceiver configured to receive information for a first group of N1 cells and for a second group of N2 cells, wherein:
 a physical downlink control channel (PDCCH) provides a downlink control information (DCI) format, and 
 the DCI format schedules one of:
 a physical downlink shared channel (PDSCH) reception, or a physical uplink shared channel (PUSCH) transmission, on one cell from the first group of N1 cells, or 
 PDSCH receptions, or PUSCH transmissions, on a number of cells up to a maximum of M cells from the second group of N2 cells, wherein M is larger than one; and 
 
   a processor operably connected to the transceiver, the processor configured to determine a total number of PDCCH receptions in a slot on a scheduling cell based on N1 and on a ratio of N2 over M,   wherein the transceiver is further configured to receive a number of PDCCHs in the slot on the scheduling cell that is not larger than the total number.   
     
     
         9 . The UE of  claim 8 , wherein:
 the DCI format schedules the PDSCH receptions, or the PUSCH transmissions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   the DCI format includes a field indicating the number of cells.   
     
     
         10 . The UE of  claim 8 , wherein:
 the DCI format schedules the PDSCH receptions, or the PUSCH transmissions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   a size of the DCI format is same for any value of the number of cells.   
     
     
         11 . The UE of  claim 8 , wherein:
 the DCI format includes a counter downlink assignment index (DAI) field with a first maximum number of bits, when the DCI format schedules the PDSCH reception, or the PUSCH transmission, on the one cell from the first group of N1 cells,   the DCI format includes the counter DAI field with a second maximum number of bits, when the DCI format schedules the PDSCH receptions, or the PUSCH transmissions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   the second maximum number of bits is larger than the first maximum number of bits.   
     
     
         12 . The UE of  claim 8 , wherein:
 the transceiver is further configured to receive a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules transmissions of first and second PUSCHs on respective first and second cells from the second group of N2 cells, 
 the first and second cells are in a same frequency band, and 
 the second DCI format includes a transmission power control (TPC) command that provides one value; 
   the processor is further configured to determine first and second powers for transmission of the first and second PUSCHs, respectively, based on the one value; and   the transceiver is further configured to transmit the first and second PUSCHs using the first and second powers, respectively.   
     
     
         13 . The UE of  claim 8 , wherein:
 the transceiver is further configured to receive a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules transmissions of first and second PUSCHs on respective first and second cells from the second group of N2 cells, 
 the first cell has a smaller index that the second cell, and 
 the second DCI format includes a downlink assignment index (DAI) field; 
   the processor is further configured to determine hybrid automatic repeat request acknowledgement (HARQ-ACK) information based on a value of the DAI field; and   the transceiver is further configured to transmit the first and second PUSCHs on the first and second cells, respectively, wherein the HARQ-ACK information is included only in the first PUSCH.   
     
     
         14 . The UE of  claim 8 , wherein the transceiver is further configured to receive:
 a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules receptions of first and second PDSCHs on respective first and second cells from the second group of N2 cells, and 
 the second DCI format includes a frequency domain resource allocation (FDRA) field that indicates resource block groups (RBGs), wherein an RBG includes:
 a first number of resource blocks (RBs) on the first cell, and 
 a second number of RBs on the second cell; and 
 
   the first and second PDSCHs over the indicated RBGs.   
     
     
         15 . A base station, comprising:
 a transceiver configured to transmit information for a first group of N1 cells and for a second group of N2 cells, wherein:
 a physical downlink control channel (PDCCH) provides a downlink control information (DCI) format, and 
 the DCI format schedules one of:
 a physical downlink shared channel (PDSCH) transmission, or a physical uplink shared channel (PUSCH) reception, on one cell from the first group of N1 cells, or 
 PDSCH transmissions, or PUSCH receptions, on a number of cells up to a maximum of M cells from the second group of N2 cells, wherein M is larger than one; and 
 
   a processor operably connected to the transceiver, the processor configured to determine a total number of PDCCH transmissions in a slot on a scheduling cell based on N1 and on a ratio of N2 over M,   wherein the transceiver is further configured to transmit a number of PDCCHs in the slot on the scheduling cell that is not larger than the total number.   
     
     
         16 . The base station of  claim 15 , wherein:
 the DCI format schedules the PDSCH transmissions, or the PUSCH receptions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   the DCI format includes a field indicating the number of cells.   
     
     
         17 . The base station of  claim 15 , wherein:
 the DCI format schedules the PDSCH transmissions, or the PUSCH receptions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   a size of the DCI format is same for any value of the number of cells.   
     
     
         18 . The base station of  claim 15 , wherein:
 the DCI format includes a counter downlink assignment index (DAI) field with a first maximum number of bits, when the DCI format schedules the PDSCH transmission, or the PUSCH reception, on the one cell from the first group of N1 cells,   the DCI format includes the counter DAI field with a second maximum number of bits, when the DCI format schedules the PDSCH transmissions, or the PUSCH receptions, on the number of cells up to the maximum of M cells from the second group of N2 cells, and   the second maximum number of bits is larger than the first maximum number of bits.   
     
     
         19 . The base station of  claim 15 , wherein the transceiver is further configured to:
 transmit a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules receptions of first and second PUSCHs on respective first and second cells from the second group of N2 cells, 
 the first cell has a smaller index that the second cell, and 
 the second DCI format includes a downlink assignment index (DAI) field indicating a hybrid automatic repeat request acknowledgement (HARQ-ACK) information report; and 
   receive the first and second PUSCHs on the first and second cells, respectively, wherein the HARQ-ACK information is included only in the first PUSCH.   
     
     
         20 . The base station of  claim 15 , wherein the transceiver is further configured to transmit:
 a second PDCCH that provides a second DCI format, wherein:
 the second DCI format schedules transmissions of first and second PDSCHs on respective first and second cells from the second group of N2 cells, and 
 the second DCI format includes a frequency domain resource allocation (FDRA) field that indicates resource block groups (RBGs), wherein an RBG includes:
 a first number of resource blocks (RBs) on the first cell, and 
 a second number of RBs on the second cell; and 
 
   the first and second PDSCHs over the indicated RBGs.