Distributed antenna system for supporting MIMO service

A distributed antenna system (DAS) supporting multiple input multiple output (MIMO) communication, comprising:

• a first node configured to
• receive MIMO downlink signals of a plurality of MIMO services, the MIMO downlink signals of each MIMO service including a first channel downlink signal and a second channel downlink signal, and
• perform, for each MIMO service, a frequency conversion of the second channel downlink signal, to a different frequency band from an original frequency band, to generate MIMO downlink signals without mutually overlapping frequency bands;
• and
• a second node configured to
• receive the MIMO downlink signals without mutually overlapping frequency bands from the first node via a single transmission line, and
• perform, for each MIMO service, a frequency conversion of the second downlink signal that have been frequency-converted by the first node (10, 20), in a complementary manner, to reconstruct the MIMO downlink signals of the original frequency band, and
• wherein the second node is configured to
• receive, from antennas, MIMO uplink signals of the plurality of MIMO services, the MIMO uplink signals of each MIMO service including a first channel uplink signal and a second channel uplink signal,
• perform, for each MIMO service, a frequency conversion of the second channel uplink signal, to a different frequency band from an original frequency band, to generate MIMO uplink signals without mutually overlapping frequency bands, and
• transmit the MIMO uplink signals without mutually overlapping frequency bands to the first node via the single transmission line;
• and
• wherein the first node is configured to frequency convert the second channel uplink signal for each MIMO service, in a complementary manner, to reconstruct the MIMO uplink signals of the original frequency band,
• characterized in that the first node or the second node is further configured to combine the second channel downlink signals of the plurality of MIMO services into a combined second channel downlink signal, and frequency-shifts the combined second channel downlink signal using a first mixer, and
• the first node or the second node is further configured to combine the second channel uplink signals of the plurality of MIMO services into a combined second channel uplink signal, and frequency-shifts the combined second channel uplink signal using a mixing signal using a second mixer.