High-order multiple-user multiple-input multiple-output operation for wireless communication systems

Abstract

Methods and apparatuses schedule resources and identify resource scheduling in a MU MIMO wireless communication system. A method for identifying resource scheduling for a UE includes receiving downlink control information; identifying, from the downlink control information, one or more DM-RS ports assigned to the UE and a PDSCH EPRE to DM-RS EPRE ratio; and identifying data intended for the UE in a resource block in a downlink subframe using the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio. A method for scheduling resources includes identifying one or more DM-RS ports to assign to a UE and a PDSCH EPRE to DM-RS EPRE ratio for identifying data intended for the UE in a resource block in a downlink subframe; and including an indication of the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio in downlink control information.

What is claimed is: 
     
       1. A method for identifying resource scheduling for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:
 receiving downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the UE, a number of layers, a scrambling identifier (SCID), and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio; 
 identifying, from the downlink control information, the one or more demodulation reference signal (DM-RS) ports assigned to the UE and a physical downlink shared channel ( the PDSCH) energy per resource element ( EPRE) to DM-RS EPRE ratio according to the number of layers; and 
 identifying distinguishing a signal including data intended for the UE in a resource block in a downlink subframe from another signal for an interfering UE in the resource block including data intended for another the interfering UE using the SCID for the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio, wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system, and 
 identifying, from the downlink control information, a DM-RS port SCID for a DM-RS port assigned to the interfering UE; 
 identifying an initialization value for a scrambling sequence for resources assigned to the interfering UE using the DM-RS port SCID; and 
 reducing interference from the interfering UE in identifying the data intended for the UE in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering UE. 
 
     
     
       2. The method of  claim 1 , wherein the UE is assigned ports from one DM-RS code division multiplexing (CDM) group, the method further comprising:
 identifying the PDSCH EPRE to DM-RS EPRE ratio and whether rate matching around another DM-RS CDM group is used from a jointly encoded signal bit field in the downlink control information. 
 
     
     
       3. The method of  claim 1 , wherein identifying the one or more DM-RS ports assigned to the UE and the PDSCH EPRE to DM-RS EPRE ratio comprises identifying the one or more DM-RS ports assigned to the UE, a number layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching is used from a jointly encoded message in the downlink control information is 0 decibels (dB) or −3 dB. 
     
     
       4. The method of  claim 1 , further comprising:
 identifying, from the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs; and 
 reducing interference from at least one of the one or more interfering UEs in identifying the data intended for the UE in the resource block using the information about one or more interfering UEs. 
 
     
     
       5. The method of  claim 1  further comprising:
 identifying, from the downlink control information, a DM-RS port scrambling identifier fora DM-RS port assigned to an interfering UE; 
 identify an initialization value for a scrambling sequence for resources assigned to the interfering UE using the DM-RS port scrambling identifier; and 
 reducing interference from the interfering UE in identifying the data intended for the UE in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering UE. 
 
     
     
       6. The method of  claim 1 , further comprising:
 identifying, from the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE; and 
 reducing interference from the interfering UE in the group of resource blocks that overlaps with resource blocks assigned to the UE in identifying the data intended for the UE. 
 
     
     
       7. A method for scheduling resources in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:
 identifying one or more demodulation reference signal (DM-RS) ports to assign to a UE and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio for identifying a signal including data intended for the UE in a resource block in a downlink subframe from another signal in the resource block including data intended for another UE; and   including an indication of the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio in downlink control information,   wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.   
     
     
       8. The method of  claim 7 , wherein including the indication of the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio in the downlink control information comprises jointly encoding an indication of the one or more DM-RS ports assigned to the UE, a number layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching is used from in the downlink control information. 
     
     
       9. The method of  claim 7  further comprising including, in the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs for reducing interference from at least one of the one or more interfering UEs. 
     
     
       10. The method of  claim 7  further comprising including, in the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the n for reducing interference from the interfering UE in the group of resource blocks that overlaps with resource blocks assigned to the UE. 
     
     
       11. An apparatus configured to identify resource scheduling for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:
 a receiver configured to receive downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the UE, a number of layers, and a scrambling identifier (SCID), and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio; and 
 a controller configured to:
 identify, from the downlink control information, the one or more demodulation reference signal (DM-RS) ports assigned to the UE, the number of layers, the SCID, and a physical downlink shared channel ( the PDSCH) energy per resource element ( EPRE) to DM-RS EPRE ratio according to the number of layers, and 
 identifydistinguish a signal including data intended for the UE in a resource block in a downlink subframe from another signal in the resource block including data intended for another UE using the SCID for the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio, 
 
 wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system, 
 wherein the controller is configured to identify, from the downlink control information, an SCID for a DM-RS port assigned to an interfering UE, and identify an initialization value for a scrambling sequence for resources assigned to the interfering UE using the DM-RS port SCID, the apparatus further comprising: 
 control receiver processing circuitry configured to reduce interference from the interfering UE in identifying the data intended for the UE in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering UE. 
 
     
     
       12. The apparatus of  claim 11 , wherein the UE is assigned ports from one DM-RS code division multiplexing (CDM) group, and wherein the controller is configured to identify the PDSCH EPRE to DM-RS EPRE ratio and whether rate matching around another DM-RS CDM group is used from a jointly encoded signal bit field in the downlink control information. 
     
     
       13. The apparatus of  claim 11 , wherein in identifying the one or more DM-RS ports assigned to the UE and the PDSCH EPRE to DM-RS EPRE ratio, the controller is configured to identify the one or more DM-RS ports assigned to the UE, a number layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching is used from a jointly encoded message in the downlink control information is 0 decibels (dB) or −3 dB. 
     
     
       14. The apparatus of  claim 11 , wherein the controller is configured to: identify, from the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs; and, the apparatus further comprising:
 control receiver processing circuitry configured to reduce interference from at least one of the one or more interfering UEs in identifying the data intended for the UE in the resource block using the information about one or more interfering UEs. 
 
     
     
       15. The apparatus of  claim 11 , wherein the controller is configured to:
 identify, from the downlink control information, a DM-RS port scrambling identifier for a DM-RS port assigned to an interfering UE;   identify an initialization value for a scrambling sequence for resources assigned to the interfering UE using the DM-RS port scrambling identifier; and   control receiver processing circuitry to reduce interference from the interfering UE in identifying the data intended for the UE in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering UE.   
     
     
       16. The apparatus of  claim 11 , wherein the controller is configured to: identify, from the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE; and, the apparatus further comprising:
 control receiver processing circuitry configured to reduce interference from the interfering UE in the group of resource blocks that overlaps with resource blocks assigned to the UE in identifying the data intended for the UE. 
 
     
     
       17. An apparatus configured to schedule resources in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:
 a transmitter; and   a controller configured to:
 identify one or more demodulation reference signal (DM-RS) ports to assign to a UE and a physical down- link shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio for identifying a signal including data intended for the UE in a resource block in a downlink subframe from another signal in the resource block including data intended for another UE, and 
 control the transmitter to include an indication of the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio in downlink control information, 
   wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.   
     
     
       18. The apparatus of  claim 17 , wherein in controlling the transmitter to include the indication of the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio in the downlink control information, the controller is configured to control the transmitter to jointly encode an indication of the one or more DM-RS ports assigned to the UE, a number layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching is used from in the downlink control information. 
     
     
       19. The apparatus of  claim 17 , wherein the controller is configured to control the transmitter to include, in the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs for reducing interference from at least one of the one or more interfering UEs. 
     
     
       20. The apparatus of  claim 17 , wherein the controller is configured to control the transmitter to include, in the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE for reducing interference from the interfering UE in the group of resource blocks that overlaps with resource blocks assigned to the UE. 
     
     
       21. A method for identifyinq resource scheduling for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:
 receiving downlink control information;   receiving data in a resource block in a downlink subframe according to a bit field in the downlink control information, wherein the downlink control information indicates one or more demodulation reference signal (DM-RS) ports assigned to the UE, a number of layers, a scrambling identifier, a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio, and whether rate matching around at least one port unassigned to the UE and in a DM-RS code division multiplexing (CDM) group is used, wherein:
 for a first value of the bit field, (i) one or more first DM-RS ports included in a first DM-RS CDM group are assigned to the UE, (ii) a PDSCH EPRE to DMRS EPRE ratio has a value of 0 dB, and (iii) the data siqnal is mapped to the resource for a second DM-RS CDM qroup unassiqned to the UE, 
 for a second value of the bit field, (i) one or more second DM-RS ports included in the first DM-RS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has a value of −3 dB, and (iii) the data siqnal is not mapped to the resource for the second DM-RS CDM group unassigned to the UE, 
 for a third value of the bit field, (i) one or more third DM-RS ports included in the second DM-RS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB, and (iii) the data siqnal is not mapped to the resource for the first DM-RS CDM group unassigned to the UE, and 
 for a fourth value of the bit field, (i) both one or more fourth DM-RS ports included in the first DM-RS CDM group and one or more fifth DM-RS ports included in the second DM-RS CDM group are assigned to the UE, and (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB; and 
   identifying data intended for the UE in the resource block in the downlink subframe using the one or more DM-RS ports assigned to the UE and the PDSCH EPRE to DM-RS EPRE ratio,   wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.   
     
     
       22. The method of claim 21, wherein the PDSCH EPRE to DMRS EPRE ratio is 0 decibels (dB) to −3 dB. 
     
     
       23. The method of claim 21, further comprising:
 identifying, from the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs.   
     
     
       24. The method of claim 21, further comprising:
 identifying, from the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE.   
     
     
       25. A method for identifying resource scheduling for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:
 receiving downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the UE, a number of layers, a scrambling identifier (SCID), and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio;   identifying, from the downlink control information, the one or more DM-RS ports assigned to one or more UE(s) and the PDSCH EPRE to DM-RS EPRE ratio according to the number of layers;   receiving a signal including one or more layers in at least one resource block, wherein the signal comprises a UE-specific signal identifiable from signals for one or more other UEs based on SCID(s) for the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio, wherein a layer is associated with a DM-RS port;   identifying, from the downlink control information, a DM-RS port SCID for a DM-RS port assigned to one of one or more other UEs;   identify an initialization value for a scrambling sequence for resources assigned to the one of the one or more other UEs using the DM-RS port SCID; and   reducing interference from the one of the one or more other UEs in identifying data intended for the UE in the resource block using the initialization value for the scrambling sequence for resources assigned to the one of the one or more other UEs.   
     
     
       26. The method of claim 25, further comprising:
 identify an initialization value for a scrambling identifier for resources assigned to one of the one more interfering UEs using the scrambling identifier.   
     
     
       27. A method for scheduling resources for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:
 identifying one or more demodulation reference signal (DM-RS) ports to assign to the UE and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio for identifying data intended for the UE in a resource block in a downlink subframe;   including an information indicating the one or more DM-RS ports assigned to the UE, a number of layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching around one or more ports from a DM-RS code division multiplexing (CDM) group unassigned to the UE is used in downlink control information;   transmitting the downlink control information; and   transmitting the data intended for the UE in the resource block in the downlink subframe according to a bit field in the downlink control information, wherein:
 for a first value of the bit field, (i) one or more first DMRS ports included in a first DMRS CDM group are assigned to the UE, (ii) a PDSCH EPRE to DMRS EPRE ratio has a value of 0 dB, and (iii) the data signal is mapped to the resource for a second DMRS CDM group unassigned to the UE, 
 for a second value of the bit field, (i) one or more second DMRS ports included in the first DMRS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has a value of −3 dB, and (iii) the data signal is not mapped to the resource for the second DMRS CDM group unassigned to the UE, 
 for a third value of the bit field, (i) one or more third DMRS ports included in the second DMRS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB, and (iii) the data signal is not mapped to the resource for the first DMRS CDM group unassigned to the UE, and 
 for a fourth value of the bit field, (i) both one or more fourth DMRS ports included in the first DMRS CDM group and one or more fifth DMRS ports included in the second DMRS CDM group are assigned to the UE, and (ii) the PDSCH EPRE to DMRS EPRE ratio has the value of −3 dB, 
   wherein the resource block in the downlink subframe includes the data for multiple users in the wireless communication system.   
     
     
       28. The method of claim 27, further comprising including, in the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs. 
     
     
       29. A method for scheduling resources for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:
 identifying one or more demodulation reference signal (DM-RS) ports to assign to the UE and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio for identifying data intended for the UE in a resource block in a downlink subframe;   including an information related to the one or more DM-RS ports assigned to the UE, a number of layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching around one or more ports from a DM-RS code division multiplexing (CDM) group unassigned to the UE is used in downlink control information;   including, in the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE;   transmitting the downlink control information; and   transmitting the data intended for the UE in the resource block in the downlink subframe based on a case determined among four cases according to a bit field in the downlink control information, wherein the four cases include:
 a first case that (i) one or more first DMRS ports included in a first DMRS CDM group are assigned to the UE, (ii) a PDSCH EPRE to DMRS EPRE ratio has a value of 0 dB, (iii) the data signal is mapped to the resource for a second DMRS CDM group unassigned to the UE, 
 a second case that (i) one or more second DMRS ports included in the first DMRS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has a value of −3 dB, and (iii) the data signal is not mapped to the resource for the second DMRS CDM group unassigned to the UE, 
 a third case that (i) one or more third DMRS ports included in the second DMRS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB, and (iii) the data signal is not mapped to the resource for the first DMRS CDM group unassigned to the UE, and 
 a fourth case that (i) both one or more fourth DMRS ports included in the first DMRS CDM group and one or more fifth DMRS ports included in the second DMRS CDM group are assigned to the UE, and (ii) the PDSCH EPRE to DMRS EPRE ratio has the value of −3 dB, 
   wherein the resource block in the downlink subframe includes the data for multiple users in the wireless communication system.    
     
     
       30. An apparatus configured to identify resource scheduling for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:
 a receiver configured to
 receive downlink control information including a bit field related to an antenna port; and 
 receive data in a resource block in a downlink subframe according to a bit field in the downlink control information, wherein the downlink control information indicates one or more demodulation reference signal (DM-RS) ports assigned to the UE, a number of layers, a scrambling identifier, a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio, and whether rate matching around at least one port unassigned to the UE and in a DM-RS code division multiplexing (CDM) group is used, wherein:
 for a first value of the bit field, (i) one or more first DM-RS ports included in a first DM-RS CDM group are assigned to the UE, (ii) a PDSCH EPRE to DMRS EPRE ratio has a value of 0 dB, and (iii) the data signal is mapped to the resource for a second DM-RS CDM group unassigned to the UE, 
 for a second value of the bit field, (i) one or more second DM-RS ports included in the first DM-RS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has a value of −3 dB, and (iii) the data signal is not mapped to the resource for the second DM-RS CDM group unassigned to the UE, 
 for a third value of the bit field, (i) one or more third DM-RS ports included in the second DM-RS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB, and (iii) the data signal is not mapped to the resource for the first DM-RS CDM group unassigned to the UE, and 
 for a fourth value of the bit field, (i) both one or more fourth DM-RS ports included in the first DM-RS CDM group and one or more fifth DM-RS ports included in the second DM-RS CDM group are assigned to the UE, and (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB; and 
 
   a controller configured to identify data intended for the UE in a resource block in a downlink subframe using the one or more DM-RS ports assigned to the UE and the PDSCH EPRE to DM-RS EPRE ratio,   wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.   
     
     
       31. The apparatus of claim 30, wherein the PDSCH EPRE to DMRS EPRE ratio is 0 decibels (dB) to −3 dB. 
     
     
       32. The apparatus of claim 30, wherein the controller is configured to identify, from the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE. 
     
     
       33. The apparatus of claim 30, wherein the controller is configured to identify, from the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs. 
     
     
       34. An apparatus configured to identify resource scheduling for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:
 a receiver configured to receive downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the UE, a number of layers, a scrambling identifier (SCID), and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio; and   a controller configured to:
 identify, from the downlink control information, the one or more DM-RS ports assigned to one or more UE(s) and the PDSCH EPRE to DM-RS EPRE ratio according to the number of layers, and 
 receive, via the receiver, a signal including one or more layers in at least one resource block, wherein the signal comprises a UE-specific signal identifiable based on SCID(s) for the one or more DM-RS ports and the PDSCH EPRE to DM-RS EPRE ratio, wherein a layer is associated with a DM-RS port, 
 identify, from the downlink control information, a DM-RS port scrambling identifier for a DM-RS port assigned to one of one or more other UEs, 
 identify an initialization value for a scrambling sequence for resources assigned to the one of the one or more other UEs using the DM-RS port scrambling identifier, and 
 control the receiver to reduce interference from the one of the one or more other UEs in identifying data intended for the UE in the resource block using the initialization value for the scrambling sequence for resources assigned to the one of the one or more other UEs. 
   
     
     
       35. The apparatus of claim 34, wherein the controller is configured to identify an initialization value for a scrambling identifier for resources assigned to one of the one more interfering UEs using the scrambling identifier. 
     
     
       36. An apparatus configured to schedule resources for a user equipment (UE) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:
 a controller configured to:
 identify one or more demodulation reference signal (DM-RS) ports to assign to a UE and a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio for identifying data intended for the UE in a resource block in a downlink subframe, and 
 include an information related to the one or more DM-RS ports assigned to the UE, a number of layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching around one or more ports from a DM-RS code division multiplexing (CDM) group unassigned to the UE is used in downlink control information; and a transmitter coupled with the controller, wherein the transmitter is configured to transmit the downlink control information, and 
   a transmitter coupled with the controller, wherein the transmitter is condigured to
 transmit the downlink control information, and 
 transmit the data intended for the UE in the resource block in the downlink subframe based on a case determined among four cases according to a bit field in the downlink control information, wherein the four cases include:
 a first case that (i) one or more first DMRS ports included in a first DMRS CDM group are assigned to the UE, (ii) a PDSCH EPRE to DMRS EPRE ratio has a value of 0 dB, (iii) the data signal is mapped to the resource for a second DMRS CDM group unassigned to the UE, 
 a second case that (i) one or more second DMRS ports included in the first DMRS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has a value of −3 dB and (iii) the data signal is not mapped to the resource for the second DMRS CDM group unassigned to the UE, 
 a third case that (i) one or more third DMRS ports included in the second DMRS CDM group are assigned to the UE, (ii) the PDSCH EPRE to DM-RS EPRE ratio has the value of −3 dB and (iii) the data signal is not mapped to the resource for the first DMRS CDM group unassigned to the UE, and 
 a fourth case that (i) both one or more fourth DMRS ports included in the first DMRS CDM group and one or more fifth DMRS ports included in the second DMRS CDM group are assigned to the UE, and (ii) the PDSCH EPRE to DMRS EPRE ratio has the value of −3 dB, 
 
   wherein the resource block in the downlink subframe includes the data for multiple users in the wireless communication system.   
     
     
       37. The apparatus of claim 36, wherein the controller is configured to include, in the downlink control information, information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more ports assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs. 
     
     
       38. The apparatus of claim 37, wherein the controller is configured to include, in the downlink control information, whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE.