Distributed digital antenna system
First Claim
Patent Images
1. A distributed digital antenna system comprising:
- a host unit that converts a first signal to a transmitted digital optical signal and that converts a received digital optical signal to a second signal;
an optical medium coupled to the host unit to carry the transmitted and received digital optical signals; and
a plurality of remote units daisy-chained along the optical medium such that each remote unit transmits an analog representation of the transmitted digital optical signal and receives radio frequency signals that are converted by the remote unit to a digitized received spectrum, each of the remote units including a summer that sums the digitized received spectrum with a corresponding digitized received spectrum from any preceding remote unit of the daisy-chained remote units to generate the received digital optical signal for transmission to the host unit.
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Abstract
An optical medium, such as fiber, is tapped to provide an antenna port wherever radio service coverage is desired. Each antenna port is a bi-directional remote unit that receives a digital optical signal from a host unit and transforms the signal to a radio frequency signal for transmission by the remote unit. The remote unit receives radio frequency signals that are converted to digital signals and summed with signals from other remote units and converted to an optical signal for transmission to the host unit.
258 Citations
24 Claims
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1. A distributed digital antenna system comprising:
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a host unit that converts a first signal to a transmitted digital optical signal and that converts a received digital optical signal to a second signal; an optical medium coupled to the host unit to carry the transmitted and received digital optical signals; and a plurality of remote units daisy-chained along the optical medium such that each remote unit transmits an analog representation of the transmitted digital optical signal and receives radio frequency signals that are converted by the remote unit to a digitized received spectrum, each of the remote units including a summer that sums the digitized received spectrum with a corresponding digitized received spectrum from any preceding remote unit of the daisy-chained remote units to generate the received digital optical signal for transmission to the host unit. - View Dependent Claims (2, 3, 4, 5, 6, 23)
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7. A distributed digital antenna system that communicates signals with a base station that is coupled to a data network, the system comprising:
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a host unit that converts radio frequency signals from the base station to digital optical signals and that converts digital optical signals from the digital antenna system to radio frequency signals for use by the base station; an optical medium coupled to the host unit that carries the digital optical signals; and a plurality of remote units daisy-chained along the optical medium such that each remote unit transmits radio frequency signals over an air interface as an analog representation of the digital optical signals from the base station and receives radio frequency signals over the air interface that are converted by a receiving remote unit to a digitized received spectrum, each of the remote units and the receiving remote unit including a summer that sums the digitized received spectrum with a corresponding digitized received spectrum from any preceding remote unit of the daisy-chained remote units to generate the received digital optical signals for use by the host unit. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A remote unit in a distributed digital antenna system that communicates signals with a base station, the remote unit comprising:
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an antenna that communicates radio frequency signals using an air interface standard; a plurality of optical-to-electrical converters that convert input digital optical signals, from a host unit coupled to the base station and a daisy-chain of previous remote units, to forward link digital electrical signals; a digital to analog converter that converts the forward link digital electrical signals to analog signals for transmission by the antenna as radio frequency signals; an analog-to-digital converter that converts radio frequency signals from the antenna to a digitized spectrum of reverse link electrical signals; and a summer that sums the reverse link electrical signals in the digitized spectrum from the analog-to-digital converter to corresponding reverse link electrical signals from the daisy-chain of previous remote units to generate an output digital optical signal. - View Dependent Claims (14, 15)
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16. A remote unit in a distributed digital antenna system that communicates signals with a base station, the remote unit comprising:
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an antenna that communicates radio frequency signals using an air interface standard; a plurality of optical-to-electrical converters that convert digital optical signals, from a host unit coupled to the base station and a daisy-chain of previous remote units, to forward link digital electrical signals, the plurality of optical-to-electrical converters further convert reverse link digital electrical signals to digital optical signals, each digital optical signal comprising a wavelength; a digital to analog converter that converts the forward link digital electrical signals to analog signals for transmission by the antenna as radio frequency signals; an analog-to-digital converter that converts radio frequency signals from the antenna to a digitized spectrum of reverse link electrical signals; a summer that sums the reverse link electrical signals in the digitized spectrum from the analog-to-digital converter to an output digital optical signal from the daisy-chain of previous remote units; and a wavelength division multiplexer that demultiplexes an input digital optical signal, comprising a plurality of wavelengths, to the digital optical signals each having a wavelength in the plurality of wavelengths, the wavelength division multiplexer further multiplexes digital optical signals to the output digital optical signal comprising the plurality of wavelengths.
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17. A method for communicating over a distributed digital antenna system, the method comprising:
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converting a first radio frequency signal from a base station to a digital optical signal; transmitting the digital optical signal over an optical medium to a plurality of remote units in a daisy-chain configuration along the optical medium; converting the digital optical signal to a forward link digital electrical signal at each remote unit; converting the forward link digital electrical signal to an analog signal for transmission by at least one of the remote units as a second radio frequency signal; receiving a third radio frequency signal over an air interface of at least one of the remote units; converting the third radio frequency signal to a received electrical signal within a digitized spectrum; and summing the digitized spectrum of the received electrical signal with a corresponding digitized spectrum of received electrical signals from previous remote units in the daisy-chain configuration. - View Dependent Claims (18, 19, 20, 21)
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22. A method for a remote terminal to communicate with a wireless terminal in a geographic area, the method comprising:
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converting an optical signal to a forward link electrical signal; converting the forward link electrical signal to a forward link analog signal; transmitting the forward link analog signal to the wireless terminal; receiving a reverse link analog signal from the wireless terminal; converting the reverse link analog signal to a reverse link electrical signal; summing a digitized spectrum of the reverse link electrical signal with a corresponding digitized spectrum of other reverse link electrical signals from other remote terminals that are daisy-chained together over an optical link; and converting the summed digitized spectrum of reverse link electrical signals to a reverse link summed optical signal for transmission to a host unit. - View Dependent Claims (24)
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Specification