Wireless distributed antenna MIMO

A radio-over-fibre MIMO communication system comprising

• one or more base transceiver stations comprising a plurality of antenna units, an optical transmitter for converting RF signals from the antenna units into optical signals, and at least one first multiplexing unit for multiplexing said optical signals into respective individual cores of a multicore fiber, or into respective individual modes of a multimode fiber, and
• a central unit accommodating
• at least one demultiplexing unit adapted for demultiplexing the individual cores of the multicore fiber, or for demultiplexing the individual modes of a multimode fiber,
• an optical receiver for receiving the optical signals output from said at least one demultiplexing unit,
• at least one processing unit for processing the signals from said optical receiver,
• wherein said optical transmitter and said optical receiver are configured to perform a MIMO communication, and
• wherein each of said one or more base transceiver stations are connected to the central unit by means of at least one backhaul multicore or multimode optical fiber,
• a plurality of said base transceiver stations, and
• at least one second multiplexing unit adapted for multiplexing the individual cores of the multicore optical fibers from each of said base transceiver stations into:
• (i) respective individual cores of said at least one backhaul multicore fiber, the at least one backhaul multicore fiber comprising a higher number of cores than each of the multicore optical fibers, or (ii) into respective individual modes of a backhaul multimode fiber, the backhaul multimode fiber comprising a higher number of modes than a number of cores of each of the multicore optical fibers,
• wherein one or more of:
• (i) the at least one first multiplexing unit, (ii) the at least one second multiplexing unit and (iii) the at least one demultiplexing unit, is a space division multiplexing unit or a space division demultiplexing unit.