A mobile communication device configured to communicate with a communication apparatus, the mobile communication device comprising: means for receiving a physical downlink control channel, PDCCH; means for receiving demodulation reference signals, DMRS, transmitted, from the communication apparatus, on antenna ports, wherein first DMRS for a first two antenna ports are transmitted using a first pattern of resource elements on first subcarrier frequencies within resource blocks of a subframe within which the first DMRS are transmitted, and second DMRS for a second two antenna ports are transmitted using a second pattern of resource elements on second subcarrier frequencies within the resource blocks of the subframe within which the first DMRS are transmitted, wherein the second subcarrier frequencies are different from the first subcarrier frequencies; wherein the first DMRS are associated with a first enhanced PDCCH transmitted using at least one of the first two antenna ports; wherein the second DMRS are associated with a second enhanced PDCCH transmitted using at least one of the second two antenna ports; means for receiving the first enhanced PDCCH associated with the first DMRS when the first enhanced PDCCH is transmitted using at least one of the first two antenna ports, and for receiving the second enhanced PDCCH associated with the second DMRS when the second enhanced PDCCH is transmitted using at least one of the second two antenna ports; and means for demodulating, when the first enhanced PDCCH is transmitted using at least one of the first two antenna ports, the first enhanced PDCCH based on the first associated DMRS, and for demodulating, when the second enhanced PDCCH is transmitted using at least one of the second two antenna ports, the second enhanced PDCCH based on the second associated DMRS. means for receiving a physical downlink control channel, PDCCH; means for receiving demodulation reference signals, DMRS, transmitted, from the communication apparatus, on antenna ports, wherein first DMRS for a first two antenna ports are transmitted using a first pattern of resource elements on first subcarrier frequencies within resource blocks of a subframe within which the first DMRS are transmitted, and second DMRS for a second two antenna ports are transmitted using a second pattern of resource elements on second subcarrier frequencies within the resource blocks of the subframe within which the first DMRS are transmitted, wherein the second subcarrier frequencies are different from the first subcarrier frequencies; wherein the first DMRS are associated with a first enhanced PDCCH transmitted using at least one of the first two antenna ports; wherein the second DMRS are associated with a second enhanced PDCCH transmitted using at least one of the second two antenna ports; means for receiving the first enhanced PDCCH associated with the first DMRS when the first enhanced PDCCH is transmitted using at least one of the first two antenna ports, and for receiving the second enhanced PDCCH associated with the second DMRS when the second enhanced PDCCH is transmitted using at least one of the second two antenna ports; and means for demodulating, when the first enhanced PDCCH is transmitted using at least one of the first two antenna ports, the first enhanced PDCCH based on the first associated DMRS, and for demodulating, when the second enhanced PDCCH is transmitted using at least one of the second two antenna ports, the second enhanced PDCCH based on the second associated DMRS. <EOS>