Communications system with multiple PDCCH with associated multiple DMRS patterns

Abstract

A communication system is presented in which a base station is provided for communicating with a plurality of mobile communication devices in a cellular communication system. The base station operates one of more communication cells and communicates subframes, with each of the plurality of communication devices within the cell(s), each comprising the communication resources of a control region for communicating a control channel and the communication resources of a data region for communicating a respective data channel. The base station communicates a control channel having a first DMRS sequence in a control region of some subframes and a control channel having a second DMRS sequence in a control region of other subframes. The second control channel may be transmitted in a radio beam focussed spatially in a direction of a communication device. The first control channel may be transmitted omnidirectionally throughout the cell(s).

The invention claimed is: 
     
       1. Communication apparatus for communicating with a plurality of mobile communication devices in a cellular communication system said communication apparatus comprising:
 a controller configured to operate at least one communication cell; 
 a transceiver configured to communicate via a plurality of antenna ports with each of a plurality of communication devices within said at least one cell, wherein: 
 said transceiver uses a plurality of communication resources for a respective physical downlink control channel (PDCCH), and a plurality of communication resources for a physical downlink shared channel (PDSCH); and 
 said transceiver is configured to communicate:
 control information in a second PDCCH, wherein said control information in said second PDCCH is communicated using a first pair of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of antenna ports associated with a different DMRS pattern. 
 
 
     
     
       2. A communication device for communicating with communication apparatus of a cellular communication system said communication device comprising:
 a controller configured to register said communication device in at least one communication cell operated by said communication apparatus; 
 a receiver configured to receive communications from said communication apparatus via a plurality of antenna ports, wherein: 
 said communications use a plurality of communication resources defining for a physical downlink control channel (PDCCH), and a plurality of communication resources for a physical downlink shared channel (PDSCH); 
 said receiver is configured to receive control information communicated in a second PDCCH, wherein said control information in said second PDCCH is communicated using a first pair of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of antenna ports associated with a different DMRS pattern; and 
 wherein said controller is configured to interpret control information communicated using said first pair of antenna ports associated with said first DMRS pattern, and for interpreting control information communicated using said second pair of antenna ports associated with said different DMRS pattern. 
 
     
     
       3. Communication apparatus for communicating with a plurality of mobile communication devices in a cellular communication system said communication apparatus comprising:
 a controller configured to operate at least one communication cell; 
 a transceiver configured to communicate with each of a plurality of communication devices within said at least one cell, wherein: 
 said transceiver uses a plurality of communication resources defining a control region for communicating control signals in a respective control channel and a plurality of communication resources defining a data region for communicating data in a respective data channel; and 
 said transceiver is configured to communicate:
 control signals in a first control channel having a first reference signal pattern; and 
 control signals in a second control channel having a second reference signal pattern; wherein said second reference signal pattern is different from said first reference signal pattern. 
 
 
     
     
       4. A communication device for communicating with communication apparatus of a cellular communication system said communication device comprising:
 a controller configured to register said communication device in at least one communication cell operated by said communication apparatus; and 
 a receiver configured to receive communications from said communication apparatus, wherein: 
 said communications use a plurality of communication resources defining a control region for communicating control signals in a respective control channel and a plurality of communication resources defining a data region for communicating data in a respective data channel; and 
 said receiver is configure to: 
 to receive control signals communicated in a first control channel having a first reference signal pattern and 
 to receive control signals communicated in a second control channel having a second reference signal pattern; 
 wherein said second reference signal pattern is different from said first reference signal pattern; 
 wherein said controller is configured to interpret control information communicated in said first control channel having a first reference signal pattern, and for interpreting control information communicated in said second control channel having a second reference signal pattern. 
 
     
     
       5. A method, performed by communication apparatus, for communicating with a plurality of mobile communication devices in a cellular communication system, the method comprising:
 operating at least one communication cell; and 
 communicating, via a plurality of antenna ports, with each of a plurality of communication devices within said at least one cell, using a plurality of communication resources for a physical downlink control 
 channel (PDCCH) and a plurality of communication resources for a physical downlink shared channel (PDSCH); 
 wherein said communicating comprises communicating control information in a second PDCCH, wherein said control information in said second PDCCH is communicated 
 using a first pair of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of antenna ports associated with a different DMRS pattern. 
 
     
     
       6. A method, performed by a communication device for communicating with communication apparatus of a cellular communication system, the method comprising:
 registering said communication device in at least one communication cell operated by said communication apparatus; 
 receiving communications transmitted from said communication apparatus via a plurality of antenna ports, wherein said communications use a plurality of communication resources defining for a physical downlink control channel (PDCCH) and a plurality of communication resources for a physical downlink shared channel (PDSCH); 
 wherein said receiving comprises receiving control information communicated in a second PDCCH, wherein said control information in said second PDCCH is communicated using a first pair of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of antenna ports associated with a different DMRS pattern; 
 interpreting said control information communicated using said first pair of antenna ports associated with said first DMRS pattern; and interpreting control information communicated using said second pair of antenna ports associated with said different DMRS pattern. 
 
     
     
       7. A method, performed by communication apparatus, of communicating with a plurality of mobile communication devices in a cellular communication system said method comprising:
 operating at least one communication cell; 
 communicating with each of a plurality of communication devices within said at least one cell using a plurality of communication resources defining a control region for communicating control signals in a control channel and a plurality of communication resources defining a data region for communicating data in a data channel; 
 wherein said communicating comprises communicating control information using a first control channel having a first reference signal pattern; and 
 communicating control information using a second control channel having a second reference signal pattern, wherein said second reference signal pattern is different from said first reference signal pattern. 
 
     
     
       8. A method, performed by a communication device, of communicating with communication apparatus of a cellular communication system said method:
 registering said communication device in at least one communication cell operated by said communication apparatus; 
 receiving communications from said communication apparatus, wherein said communications use a plurality of communication resources defining a control region for communicating control signals in a control channel and a plurality of communication resources defining a data region for communicating data in a data channel; 
 receiving control signals in a first control channel having a first reference signal pattern; 
 interpreting control information communicated in said first control channel having the first reference signal pattern; 
 receiving a second control channel having a second reference signal pattern, wherein said second reference signal pattern is different from said first reference signal pattern; and 
 interpreting control information communicated in said second control channel having a second reference signal pattern. 
 
     
     
       9. Communication apparatus for communicating with at least one mobile communication device, the communication apparatus comprising:
 a plurality of antenna ports; and 
 a transmitter configured to transmit at least one control signal of a first physical downlink control channel (PDCCH) to the at least one mobile communication device via at least one of the plurality of antenna ports; 
 wherein the transmitter is further configured to transmit at least one control signal of a second PDCCH; and 
 wherein the second PDCCH is transmitted to the at least one mobile communication device via a first pair of the plurality of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of the plurality of antenna ports associated with a second DMRS pattern; 
 wherein a pattern of the first DMRS pattern is different from a pattern of the second DMRS pattern. 
 
     
     
       10. Communication apparatus according to  claim 9 , wherein the least one of the first DMRS pattern and the pattern of the second DMRS pattern comprises at least one resource element. 
     
     
       11. Communication apparatus according to  claim 10 , wherein the at least one resource element comprises time and frequency. 
     
     
       12. A mobile communication device for communicating with a communication apparatus, the mobile communication device comprising:
 a receiver configured to receive at least one control signal of a first physical downlink control channel (PDCCH) transmitted via at least one of a plurality of antenna ports of the communication apparatus, wherein the receiver is further configured to receive at least one control signal of a second PDCCH, wherein the second PDCCH is transmitted via a first pair of the plurality of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of the plurality of antenna ports associated with a second DMRS pattern; and 
 a controller configured to demodulate the second PDCCH based on at least one of the first DMRS pattern and the second DMRS pattern 
 wherein a pattern of the first DMRS pattern is different from a pattern of the second DMRS pattern. 
 
     
     
       13. Communication apparatus according to  claim 12 , wherein the at least one of the pattern of the first DMRS pattern and the pattern of the second DMRS pattern comprises at least one resource element. 
     
     
       14. Communication apparatus according to  claim 13 , wherein the at least one resource element comprises time and frequency. 
     
     
       15. A method, performed by a communication apparatus, of communicating with at least one mobile communication device, the method comprising:
 transmitting at least one control signal of a first physical downlink control channel (PDCCH) to the at least one mobile communication device via at least one of a plurality of antenna ports; 
 transmitting at least one control signal of a second PDCCH to the at least one mobile communication device via a first pair of the plurality of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of the plurality of antenna ports associated with a second DMRS pattern 
 wherein a pattern of the first DMRS pattern is different from a pattern of the second DMRS pattern. 
 
     
     
       16. A method, performed by a mobile communication device, of communicating with a communication apparatus, the method comprising:
 receiving at least one control signal of a first physical downlink control channel (PDCCH) transmitted via at least one of a plurality of antenna ports of the communication apparatus; and 
 receiving at least one control signal of a second PDCCH transmitted via a first pair of the plurality of antenna ports associated with a first demodulation reference signal (DMRS) pattern and a second pair of the plurality of antenna ports associated with a second DMRS pattern; and 
 demodulating the second PDCCH based on at least one of the first DMRS pattern and the second DMRS pattern 
 wherein a pattern of the first DMRS pattern is different from a pattern of the second DMRS pattern. 
 
     
     
       17. A non-transitory computer readable medium comprising instructions operable to program a programmable processor to implement communication apparatus according to  claim 9 . 
     
     
       18. A non-transitory computer readable medium comprising instructions operable to program a programmable processor to implement mobile communication device according to  claim 12 .