Distributed antenna system for MIMO technologies
First Claim
1. A distributed antenna system comprising:
- a radio interface unit adapted to receive a plurality of downlink MIMO spatial streams fromat least one base station for providing a multi-input, multi-output (MIMO) system, the radio interface unit including at least one mixer adapted for converting at least one of the plurality of downlink MIMO spatial streams from a native frequency band to a different, non-overlapping frequency band and a downlink duplexer adapted for combining each of the plurality of downlink MIMO spatial streams to form a combined downlink signal on to a common transmission medium;
a base unit adapted to receive the combined downlink signal over the common transmission medium, and for transmitting the combined downlink signal to a plurality of remote units over a separate communication medium connecting the base unit to each remote unit;
each remote unit among the plurality of remote units including a multiplexer adapted for connecting the remote unit with a plurality of antenna units and for transmitting the combined downlink signal to each of the antenna units over an a separate antenna unit communication medium connecting the remote unit to each antenna unit;
each antenna unit including a de-duplexer adapted for separating the combined downlink signal into each of the plurality of downlink MIMO spatial streams and at least one downlink mixer adapted for converting each of the plurality of downlink MIMO spatial streams to the native frequency band; and
a plurality of MIMO antennae coupled to each antenna unit, one for transmitting each of the plurality of downlink MIMO spatial streams.
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Accused Products
Abstract
The invention is directed to a method and system for supporting MIMO technologies which can require the transport of multiple spatial streams on a traditional Distributed Antenna System (DAS). According to the invention, at one end of the DAS, each spatial stream is shifted in frequency to a pre-assigned band (such as a band at a frequency lower than the native frequency) that does not overlap the band assigned to other spatial streams (or the band of any other services being carried by the DAS). Each of the spatial streams can be combined and transmitted as a combined signal over a common coaxial cable. At the other “end” of the DAS, the different streams are shifted back to their original (overlapping) frequencies but retain their individual “identities” by being radiated through physically separate antenna elements.
825 Citations
21 Claims
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1. A distributed antenna system comprising:
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a radio interface unit adapted to receive a plurality of downlink MIMO spatial streams from at least one base station for providing a multi-input, multi-output (MIMO) system, the radio interface unit including at least one mixer adapted for converting at least one of the plurality of downlink MIMO spatial streams from a native frequency band to a different, non-overlapping frequency band and a downlink duplexer adapted for combining each of the plurality of downlink MIMO spatial streams to form a combined downlink signal on to a common transmission medium; a base unit adapted to receive the combined downlink signal over the common transmission medium, and for transmitting the combined downlink signal to a plurality of remote units over a separate communication medium connecting the base unit to each remote unit; each remote unit among the plurality of remote units including a multiplexer adapted for connecting the remote unit with a plurality of antenna units and for transmitting the combined downlink signal to each of the antenna units over an a separate antenna unit communication medium connecting the remote unit to each antenna unit; each antenna unit including a de-duplexer adapted for separating the combined downlink signal into each of the plurality of downlink MIMO spatial streams and at least one downlink mixer adapted for converting each of the plurality of downlink MIMO spatial streams to the native frequency band; and a plurality of MIMO antennae coupled to each antenna unit, one for transmitting each of the plurality of downlink MIMO spatial streams. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for conveying a plurality of MIMO spatial streams over a distributed antenna system comprising:
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receiving from a base station, each downlink MIMO spatial stream having a native frequency;
converting each of the downlink MIMO spatial streams from the native frequency to a different, non-overlapping frequency band;
combining each of the downlink MIMO spatial streams to form a combined downlink signal;transmitting the combined downlink signal to a base unit;
transmitting the combined downlink signal to a plurality of remote units over a separate communication medium connecting the base unit to each remote unit;
providing a multiplexer adapted for connecting the remote unit with a plurality of antenna units and transmitting the combined downlink signal to each of the antenna units over an antenna unit communication medium;
separating, at respective ones of the antenna units, the combined downlink signal into each of the downlink MIMO spatial streams converting each of the downlink MIMO spatial streams to the native frequency band; and
transmitting each of the downlink MIMO spatial streams through an associated antenna, at respective ones of the antenna units, the combined downlink signal into each of the downlink MIMO spatial streams converting each of the downlink MIMO spatial streams to the native frequency band; and
transmitting each of the downlink MIMO spatial streams through an associated antenna. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A distributed antenna system comprising:
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a radio interface unit adapted to receive a plurality of downlink MIMO spatial streams from at least one base station, the radio interface unit including at least one mixer adapted for converting each of the downlink MIMO spatial streams from a native frequency bank to a different, non-overlapping frequency bank and a downlink duplexer adapted for combining each of the downlink MIMO spatial streams to form a combined downlink signal on to a common transmission medium; a base unit adapted to receive the combined downlink signal over the common transmission medium, and for transmitting the combined downlink signal to a plurality of remote units over a separate communication medium connecting the base unit to each remote unit; each remote unit including a multiplexer adapted for connecting the remote unit with a plurality of antenna units and for transmitting the combined downlink signal to each of the antenna units over an antenna unit communication medium; a plurality of MIMO antennae; a de-duplexer adapted for separating the combined downlink signal into each of the downlink MIMO spatial streams; and at least one downlink mixer adapted for converting each of the downlink MIMO spatial streams to the native frequency band.
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Specification