(19) United States
`(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2010/0177760 A1
`(12) Patent Application Publication (10) Pub. No.: US 2010/0177760 A1
`(43) Pub. Date:
`Jul. 15, 2010
`Cannon et al.
`Cannon et al.
`(43) Pub. Date: Jul. 15, 2010
`
`
`US 20100177760A1
`US 20100177760A1
`
`(54)
`(54)
`
`(75)
`(75)
`
`(73)
`(73)
`
`(21)
`(21)
`(22)
`(22)
`
`(60)
`(60)
`
`SYSTEMS AND METHODS FOR IMPROVED
`SYSTEMIS AND METHODS FOR IMPROVED
`DIGITAL RF TRANSPORT IN DISTRIBUTED
`DIGITAL RF TRANSPORT IN DISTRIBUTED
`ANTENNA SYSTEMS
`ANTENNASYSTEMS
`
`Inventors:
`Inventors:
`
`Jeffrey J. Cannon, Victoria, MN
`Jeffrey J. Cannon, Victoria, MN
`(US); Dean Zavadsky, Shakopee,
`(US); Dean Zavadsky, Shakopee,
`MN (US); Philip M. Wala, Savage,
`MN (US); Philip M. Wala, Savage,
`MN (US)
`MN (US)
`Correspondence Address:
`Correspondence Address:
`FOGG & POWERS LLC
`FOGG & POWERS LLC
`5810 W 78TH STREET, SUITE 100
`5810 W 78TH STREET, SUITE 100
`MINNEAPOLIS, MN 55439 (US)
`MINNEAPOLIS, MN 55439 (US)
`Assignee:
`ADC
`Assignee:
`ADC
`TELECOMMUNICATIONS,
`TELECOMMUNICATIONS,
`INC. Eden Prairie, MN (US)
`INC., Eden Prairie, MN (US)
`12/686,488
`12/686,488
`
`Appl. No.:
`Appl. No.:
`
`Filed:
`Filed:
`
`Jan. 13, 2010
`Jan. 13, 2010
`
`Related U.S. Application Data
`Related US. Application Data
`Provisional application No. 61/144,349, filed on Jan.
`Provisional application No. 61/144,349, filed on Jan.
`13, 2009.
`13, 2009.
`
`Publication Classification
`Publication Classification
`
`(51) Int. Cl.
`(51)
`Int. Cl.
`(2006.01)
`HO4, 3/00
`(2006.01)
`H04] 3/00
`(2006.01)
`H04B I/38
`(2006.01)
`H04B 1/38
`(2006.01)
`H04L 27/00
`(2006.01)
`H04L 27/00
`(52) U.S. Cl. .......................... 370/345; 375/219; 375/316
`(52) use. .......................... 370/345; 375/219; 375/316
`
`ABSTRACT
`(57)
`ABSTRACT
`(57)
`Systems and methods for improved digital RF transport in a
`Systems and methods for improved digital RF transport in a
`DAS are provided. In one embodiment, a transceiver com
`DAS are provided. In one embodiment, a transceiver com-
`prises: a receive path circuit including an RF reception inter
`prises: a receive path circuit including an RF reception inter-
`face coupled to an ADC, the ADC receiving a down-con
`face coupled to an ADC, the ADC receiving a down-con-
`verted analog RF spectrum from the RF reception interface
`verted analog RF spectrum from the RF reception interface
`and producing a digitized RF spectrum at an input sampling
`and producing a digitized RF spectrum at an input sampling
`rate; a logic device receiving the digitized RF spectrum and
`rate; a logic device receiving the digitized RF spectrum and
`producing a first set of baseband data samples at a first sam
`producing a first set of baseband data samples at a first sam-
`pling rate, corresponding to a first spectral region of the
`pling rate, corresponding to a first spectral region of the
`analog RF spectrum and a second set of baseband data
`analog RF spectrum and a second set of baseband data
`samples at a second sampling rate, corresponding to a second
`samples at a second sampling rate, corresponding to a second
`spectral region of the analog RF spectrum. The logic device
`spectral region of the analog RF spectrum. The logic device
`maps the first set and second sets of baseband data samples to
`maps the first set and second sets of baseband data samples to
`a respective first set and second set of timeslots of a serial data
`a respective first set and second set oftimeslots of a serial data
`stream transport frame.
`stream transport frame.
`
`106
`106
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`DART
`
`
`DART E.
`-.
`
`107
`O7
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`107
`107
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`DART
`DART
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`Module
`Module
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`
`106
`106
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`1OO
`100
`
`132
`132
`
`108
`108
`
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`106
`106
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`106
`106
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`132
`132
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`DART
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`r
`‘
`
`132
`132
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`107
`107
`
`130
`130
`
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`Scriber
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`130 130
`130
`130
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`.
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` 107
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`107
`
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`DART
`Module
`I Module
`
`130
`130
`
`132
`1 32
`
`102
`102
`
`1 10
`110
`
`O
`O
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`132
`132
`
`DART
`DART
`Module
`Module
`
`Telephone
`Telephone
`System
`System
`Network
`Network
`
`BTS
`BTS
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`Gatewa
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`y
`y
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`P
`Network
`Network
`
`124
`124
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`JMA EX1004
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`

`

`Patent Application Publication
`Patent Application Publication
`
`Jul. 15, 2010 Sheet 1 of 10
`Jul. 15, 2010 Sheet 1 0f 10
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`US 2010/0177760 A1
`US 2010/0177760 A1
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`Jul. 15, 2010 Sheet 2 of 10
`Jul. 15, 2010 Sheet 2 0f 10
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`US 2010/0177760 A1
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`Patent Application Publication
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`Patent Application Publication
`Patent Application Publication
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`Jul. 15, 2010 Sheet 5 of 10
`Jul. 15, 2010 Sheet 5 0f 10
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`US 2010/0177760 A1
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`Patent Application Publication
`Patent Application Publication
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`Jul. 15, 2010 Sheet 6 of 10
`Jul. 15, 2010 Sheet 6 0f 10
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`Jul. 15, 2010 Sheet 8 of 10
`Jul. 15, 2010 Sheet 8 0f 10
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`Jul. 15, 2010 Sheet 9 of 10
`Jul. 15, 2010 Sheet 9 0f 10
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`Patent Application Publication
`Patent Application Publication
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`Jul. 15, 2010 Sheet 10 of 10
`Jul. 15, 2010 Sheet 10 0f 10
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`US 2010/0177760 A1
`US 2010/0177760 A1
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`

`US 2010/0177760 A1
`US 2010/0177760 A1
`
`Jul. 15, 2010
`Jul. 15,2010
`
`SYSTEMS AND METHODS FOR IMPROVED
`SYSTEMS AND METHODS FOR IMPROVED
`DIGITAL RF TRANSPORT IN DISTRIBUTED
`DIGITAL RF TRANSPORT IN DISTRIBUTED
`ANTENNA SYSTEMS
`ANTENNASYSTEMS
`
`CROSS-REFERENCE TO RELATED
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`APPLICATIONS
`0001. This application claims the benefit of U.S. Provi
`[0001] This application claims the benefit of US. Provi-
`sional Application No. 61/144,349, filed on Jan. 13, 2009,
`sional Application No. 61/144,349, filed on Jan. 13, 2009,
`which is incorporated herein by reference in its entirety.
`which is incorporated herein by reference in its entirety.
`BACKGROUND
`BACKGROUND
`0002 A Distributed Antenna System (DAS) is a network
`[0002] A Distributed Antenna System (DAS) is a network
`of spatially separated antenna nodes connected to a common
`of spatially separated antenna nodes connected to a common
`node via a transport medium that provides wireless service
`node Via a transport medium that provides wireless service
`within a geographic area or structure. Common wireless com
`within a geographic area or structure. Common wireless com-
`munication system configurations employ a host unit as the
`munication system configurations employ a host unit as the
`common node, which is located at a centralized location (for
`common node, which is located at a centralized location (for
`example, at a facility that is controlled by a wireless service
`example, at a facility that is controlled by a wireless service
`provider). The antenna nodes and related broadcasting and
`provider). The antenna nodes and related broadcasting and
`receiving equipment, located at a location that is remote from
`receiving equipment, located at a location that is remote from
`the host unit (for example, at a facility or site that is not
`the host unit (for example, at a facility or site that is not
`controlled by the wireless service provider), are also referred
`controlled by the wireless service provider), are also referred
`to as “remote units. Radio frequency (RF) signals are com
`to as “remote units.” Radio frequency (RF) signals are com-
`municated between the host unit and one or more remote
`municated between the host unit and one or more remote
`units. In Such a DAS, the host unit is typically communica
`units. In such a DAS, the host unit is typically communica-
`tively coupled to one or more base stations (for example, via
`tively coupled to one or more base stations (for example, via
`wired connection or via wireless connection) which allow
`wired connection or via wireless connection) which allow
`bidirectional communications between wireless subscriber
`bidirectional communications between wireless subscriber
`units within the DAS service area and communication net-
`units within the DAS service area and communication net
`works such as, but not limited to, cellular phone networks, the
`works such as, but not limited to, cellular phone networks, the
`public switch telephone network (PSTN) and the Internet. A
`public switch telephone network (PSTN) and the Internet. A
`DAS can provide, by its nature, an infrastructure within a
`DAS can provide, by its nature, an infrastructure within a
`community that can scatter remote units across a geographic
`community that can scatter remote units across a geographic
`area for providing wireless services across that area.
`area for providing wireless services across that area.
`0003. A digital DAS is a system wherein the host unit and
`[0003] A digital DAS is a system wherein the host unit and
`remote units transport radio signal information to one another
`remote units transport radio signal information to one another
`by digital means (for example, by digitally sampling a wire
`by digital means (for example, by digitally sampling a wire-
`less radio frequency (RF) spectrum at a remote unit and
`less radio frequency (RF) spectrum at a remote unit and
`transmitting the digital sample data to the host unit by fiber
`transmitting the digital sample data to the host unit by fiber
`optics). One problem with the digital DAS occurs when radio
`optics). One problem with the digital DAS occurs when radio
`signals of interest within the RF spectrum are separated by
`signals of interest within the RF spectrum are separated by
`bandwidths containing no signals interest. In that case, fiber
`bandwidths containing no signals interest. In that case, fiber
`bandwidth within the digital DAS is wasted because all of the
`bandwidth within the digital DAS is wasted because all of the
`digital samples need to be transported at a rate Sufficient to
`digital samples need to be transported at a rate sufficient to
`cover the full range of frequencies, not just the portions con
`cover the full range of frequencies, not just the portions con-
`taining signals of interest.
`taining signals of interest.
`0004 For the reasons stated above and for other reasons
`[0004]
`For the reasons stated above and for other reasons
`stated below which will become apparent to those skilled in
`stated below which will become apparent to those skilled in
`the art upon reading and understanding the specification,
`the art upon reading and understanding the specification,
`there is a need in the art for improved systems and methods for
`there is a need in the art for improved systems and methods for
`digital RF transport.
`digital RF transport.
`
`SUMMARY
`SUMMARY
`0005 Systems and methods for improved digital RF trans
`[0005]
`Systems and methods for improved digital RF trans-
`port in a DAS are provided. In one embodiment, a transceiver
`port in a DAS are provided. In one embodiment, a transceiver
`comprises: a receive path circuit including an RF reception
`comprises: a receive path circuit including an RF reception
`interface coupled to an ADC, the ADC receiving a down
`interface coupled to an ADC, the ADC receiving a down-
`converted analog RF spectrum from the RF reception inter
`converted analog RF spectrum from the RF reception inter-
`face and producing a digitized RF spectrum at an input Sam
`face and producing a digitized RF spectrum at an input sam-
`pling rate; a logic device receiving the digitized RF spectrum
`pling rate; a logic device receiving the digitized RF spectrum
`and producing a first set of baseband data samples at a first
`and producing a first set of baseband data samples at a first
`sampling rate, corresponding to a first spectral region of the
`sampling rate, corresponding to a first spectral region of the
`analog RF spectrum and a second set of baseband data
`analog RF spectrum and a second set of baseband data
`
`samples at a second sampling rate, corresponding to a second
`samples at a second sampling rate, corresponding to a second
`spectral region of the analog RF spectrum. The logic device
`spectral region of the analog RF spectrum. The logic device
`maps the first set and second sets of baseband data samples to
`maps the first set and second sets of baseband data samples to
`a respective first set and second set of timeslots of a serial data
`a respective first set and second set oftimeslots of a serial data
`stream transport frame.
`stream transport frame.
`DRAWINGS
`DRAWINGS
`0006 Understanding that the drawings depict only exem
`[0006] Understanding that the drawings depict only exem-
`plary embodiments of the present invention and are not there
`plary embodiments ofthe present invention and are not there-
`fore to be considered limiting in scope, the exemplary
`fore to be considered limiting in scope,
`the exemplary
`embodiments will be described with additional specificity
`embodiments will be described with additional specificity
`and detail through the use of the accompanying drawings, in
`and detail through the use of the accompanying drawings, in
`which:
`which:
`0007 FIG. 1 is a block diagram of a distributed antenna
`[0007]
`FIG. 1 is a block diagram of a distributed antenna
`system of one embodiment of the present invention;
`system of one embodiment of the present invention;
`0008 FIG. 2 is a block diagram of a remote unit of one
`[0008]
`FIG. 2 is a block diagram of a remote unit of one
`embodiment of the present invention;
`embodiment of the present invention;
`0009 FIG. 3 is a block diagram of a host unit of one
`[0009]
`FIG. 3 is a block diagram of a host unit of one
`embodiment of the present invention;
`embodiment of the present invention;
`0010 FIGS. 4A-4C illustrate mapping of RF spectral
`[0010]
`FIGS. 4A-4C illustrate mapping of RF spectral
`regions to transport frame timeslots, of one embodiment of
`regions to transport frame timeslots, of one embodiment of
`the present invention;
`the present invention;
`0011
`FIG. 5 is a block diagram illustrating a DART Mod
`[0011]
`FIG. 5 is a block diagram illustrating a DART Mod-
`ule of one embodiment of the present invention;
`ule of one embodiment of the present invention;
`0012 FIG. 6 is a block diagram illustrating an FPGA
`[0012]
`FIG. 6 is a block diagram illustrating an FPGA
`configuration for a DART Module of one embodiment of the
`configuration for a DART Module of one embodiment of the
`present invention;
`present invention;
`0013 FIG. 7 is a flow chart illustrating a method of one
`[0013]
`FIG. 7 is a flow chart illustrating a method of one
`embodiment of the present invention;
`embodiment of the present invention;
`0014 FIG. 8 is a flow chart illustrating a method of one
`[0014]
`FIG. 8 is a flow chart illustrating a method of one
`embodiment of the present invention; and
`embodiment of the present invention; and
`(0015 FIG. 9 is a flow chart illustrating a method of one
`[0015]
`FIG. 9 is a flow chart illustrating a method of one
`embodiment of the present invention.
`embodiment of the present invention.
`0016. In accordance with common practice, the various
`[0016]
`In accordance with common practice, the various
`described features are not drawn to scale but are drawn to
`described features are not drawn to scale but are drawn to
`emphasize features relevant to the present invention. Refer
`emphasize features relevant to the present invention. Refer-
`ence characters denote like elements throughout figures and
`ence characters denote like elements throughout figures and
`text.
`text.
`
`DETAILED DESCRIPTION
`DETAILED DESCRIPTION
`0017 Embodiments of the present invention address the
`[0017] Embodiments of the present invention address the
`problem of efficiently transporting multiple non-adjacent
`problem of efiiciently transporting multiple non-adjacent
`communications bands within the digital transport of a dis
`communications bands within the digital transport of a dis-
`tributed antenna system. This is accomplished by segregating
`tributed antenna system. This is accomplished by segregating
`from a digitized RF spectrum a plurality of smaller spectral
`from a digitized RF spectrum a plurality of smaller spectral
`regions that include relevant signals of interest, and discard
`regions that include relevant signals of interest, and discard-
`ing information not within those spectral regions. This seg
`ing information not within those spectral regions. This seg-
`regation further allows the spectral regions to be processed
`regation further allows the spectral regions to be processed
`independently, and each independently re-sampled (at a sam
`independently, and each independently re-sampled (at a sam-
`pling rate based on their respective bandwidths) so that they
`pling rate based on their respective bandwidths) so that they
`can be transmitted over a common serial transport link. Each
`can be transmitted over a common serial transport link. Each
`spectral region is transmitted using a number of timeslots in
`spectral region is transmitted using a number of timeslots in
`the serial bit stream that is a function of their respective
`the serial bit stream that is a function of their respective
`bandwidths rather than the bandwidth of the entire digitized
`bandwidths rather than the bandwidth of the entire digitized
`RF spectrum.
`RF spectrum.
`0018 FIG. 1 is a block diagram of a distributed antenna
`[0018]
`FIG. 1 is a block diagram of a distributed antenna
`system (DAS) 100 of one embodiment of the present inven
`system (DAS) 100 of one embodiment of the present inven-
`tion for receiving and distributing radio frequency signals
`tion for receiving and distributing radio frequency signals
`within a coverage area. DAS100 includes a host unit 102 and
`within a coverage area. DAS 100 includes a host unit 102 and
`a plurality of remote units 106. At the physical layer, host
`a plurality of remote units 106. At the physical layer, host
`units 102 and remote units 106 are communicatively coupled
`units 102 and remote units 106 are communicatively coupled
`via a communication link 130 to form a bidirectional com-
`via a communication link 130 to form a bidirectional com
`munication network comprising a plurality of point-to-point
`munication network comprising a plurality of point-to-point
`
`

`

`US 2010/0177760 A1
`US 2010/0177760 A1
`
`Jul. 15, 2010
`Jul. 15,2010
`
`communication links 130. In one embodiment, one or more of
`communication links 13 0. In one embodiment, one or more of
`communication links 130 are fiber optic cable as indicated in
`communication links 130 are fiber optic cable as indicated in
`FIG. 1. Optionally, host units 102 and remote units 106 may
`FIG. 1. Optionally, host units 102 and remote units 106 may
`be interconnected via coaxial cable, or a combination of both
`be interconnected Via coaxial cable, or a combination of both
`coaxial cable and fiber optic cable. Additionally, in other
`coaxial cable and fiber optic cable. Additionally, in other
`embodiments, one or more of communication links 130 are
`embodiments, one or more of communication links 130 are
`wireless millimeter wave links (e.g. E. Band/70 GHz radio).
`wireless millimeter wave links (e.g. E Band/70 GHZ radio).
`Here a millimeter signal transceiver is coupled to host unit
`Here a millimeter signal transceiver is coupled to host unit
`102 and each remote unit 106 on each end of communication
`102 and each remote unit 106 on each end of communication
`link 130. In yet another embodiment, one or more of commu
`link 130. In yet another embodiment, one or more of commu-
`nication links 130 a microwave radio links where microwave
`nication links 130 a microwave radio links where microwave
`radio transceivers are coupled to host unit 102 and remote
`radio transceivers are coupled to host unit 102 and remote
`units 106.
`units 106.
`0.019
`Remote units 106 each house electronic devices and
`[0019] Remote units 106 each house electronic devices and
`systems used for wirelessly transmitting and receiving modu
`systems used for wirelessly transmitting and receiving modu-
`lated radio frequency (RF) communications via antenna 107
`lated radio frequency (RF) communications via antenna 107
`with one or more mobile subscriber units 108. Host unit 102
`with one or more mobile subscriber units 108. Host unit 102
`is coupled to at least one base transceiver station (BTS) 110
`is coupled to at least one base transceiver station (BTS) 110
`often referred to as a base station. BTS 110 communicates
`often referred to as a base station. BTS 110 communicates
`Voice and other data signals between the respective host unit
`voice and other data signals between the respective host unit
`102 and a larger communication network via a gateway 124
`102 and a larger communication network via a gateway 124
`coupled to a telephone system network 122 (for example, the
`coupled to a telephone system network 122 (for example, the
`public switched telephone network and/or wireless service
`public switched telephone network and/or wireless service
`provider networks) and an internet protocol (IP) network 120,
`provider networks) and an internet protocol (IP) network 120,
`such as the Internet. In one embodiment, DAS100 comprises
`such as the Internet. In one embodiment, DAS 100 comprises
`part of a cellular telephone network and subscriber units 108
`part of a cellular telephone network and subscriber units 108
`are cellular telephones. In alternate embodiments, BTS 110
`are cellular telephones. In alternate embodiments, BTS 110
`and host unit 102 may be interconnected via coaxial cable,
`and host unit 102 may be interconnected via coaxial cable,
`fiber optic cable, wireless communication links, or any com
`fiber optic cable, wireless communication links, or any com-
`bination thereof.
`bination thereof.
`0020 Downlink RF signals are received from the BTS 110
`[0020] Downlink RF signals are received from the BTS 110
`at the host unit 102, which the host unit 102 uses to generate
`at the host unit 102, which the host unit 102 uses to generate
`one or more downlink transport signals for transmitting to one
`one or more downlink transport signals for transmitting to one
`or more of the remote units 106. Each such remote unit 106
`or more of the remote units 106. Each such remote unit 106
`receives at least one downlink transport and reconstructs the
`receives at least one downlink transport and reconstructs the
`downlink RF signals from the downlink transport signal and
`downlink RF signals from the downlink transport signal and
`causes the reconstructed downlink RF signals to be radiated
`causes the reconstructed downlink RF signals to be radiated
`from a remote antenna 107 coupled to or included in that
`from a remote antenna 107 coupled to or included in that
`remote unit 106. A similar process is performed in the uplink
`remote unit 106. A similar process is performed in the uplink
`direction. Uplink RF signals received at one or more remote
`direction. Uplink RF signals received at one or more remote
`units 106 from subscriber 108 are used to generate respective
`units 106 from subscriber 108 are used to generate respective
`uplink transport signals that are transmitted from the respec
`uplink transport signals that are transmitted from the respec-
`tive remote units 106 to the host unit 102. The host unit 102
`tive remote units 106 to the host unit 102. The host unit 102
`receives and combines the uplink transport signals transmit
`receives and combines the uplink transport signals transmit-
`ted from the multiple remote units 106. The host unit 102
`ted from the multiple remote units 106. The host unit 102
`communicates the combined uplink RF signals to the BTS
`communicates the combined uplink RF signals to the BTS
`110 over a broadband transport medium, Such as a coaxial
`110 over a broadband transport medium, such as a coaxial
`cable.
`cable.
`0021 DAS 100 comprises a digital DAS transport mean
`[0021] DAS 100 comprises a digital DAS transport mean-
`ing that the downlink and uplink transport signals transmitted
`ing that the downlink and uplink transport signals transmitted
`between host unit 102 and remote units 106 over communi-
`between host unit 102 and remote units 106 over communi
`cation links 130 are generated by digitizing the downlink and
`cation links 130 are generated by digitizing the downlink and
`uplink RF signals, respectively. In other words, the downlink
`uplink RF signals, respectively. In other words, the downlink
`and uplink transport signals are not analog RF signals but
`and uplink transport signals are not analog RF signals but
`instead are digital data signals representing digital RF
`instead are digital data signals representing digital RF
`samples of a modulated RF signal. These digital data signals,
`samples of a modulated RF signal. These digital data signals,
`which may be alternately referred to herein as “digital RF'.
`which may be alternately referred to herein as “digital RF”,
`“digitally sampled RF and “digital baseband', may com
`“digitally sampled RF” and “digital baseband”, may com-
`prise digital representations of an RF, IF or baseband version
`prise digital representations of an RF, IF or baseband version
`of the original RF signal. Further, these samples may be
`of the original RF signal. Further, these samples may be
`defined as real samples, or as pairs of complex (IQ or quadra
`defined as real samples, or as pairs of complex (IQ or quadra-
`ture) samples. For example, if a particular communication
`ture) samples. For example, if a particular communication
`signal destined for transmission to subscriber unit 108 is a
`signal destined for transmission to subscriber unit 108 is a
`modulated RF signal in the 900 MHz band, then host unit 102
`modulated RF signal in the 900 MHZ band, then host unit 102
`
`will generate baseband digital samples of the modulated 900
`will generate baseband digital samples of the modulated 900
`MHz. RF signal from BTS 110, which are then distributed by
`MHZ RF signal from BTS 110, which are then distributed by
`host unit 102 to the remote units 106. Alternatively, an all
`host unit 102 to the remote units 106. Alternatively, an all-
`digital BTS may generate baseband digital samples directly.
`digital BTS may generate baseband digital samples directly.
`At the remote units, the digital samples of the modulated RF
`At the remote units, the digital samples of the modulated RF
`signal are converted from digital into an analog RF signal to
`signal are converted from digital into an analog RF signal to
`be wirelessly radiated from the antennas 107. In the uplink
`be wirelessly radiated from the antennas 107. In the uplink
`analog RF signals received at remote unit 106 are digitally
`analog RF signals received at remote unit 106 are digitally
`sampled to generate digital RF data samples for the uplink
`sampled to generate digital RF data samples for the uplink
`transport signals. BTS 110, host unit 102 and remote units
`transport signals. BTS 110, host unit 102 and remote units
`106 each accommodate processing communication signals
`106 each accommodate processing communication signals
`for multiple bands and multiple modulation schemes simul
`for multiple bands and multiple modulation schemes simul-
`taneously. In the embodiment shown in FIG. 1, each remote
`taneously. In the embodiment shown in FIG. 1, each remote
`unit 106 and host unit 102 comprises a digital to analog radio
`unit 106 and host unit 102 comprises a digital to analog radio
`frequency transceiver (DART) module 132 configured to con
`frequency transceiver (DART) module 132 configured to con-
`serve the available bandwidth of the communication links
`serve the available bandwidth of the communication links
`130 by separating and individually processing spectral
`130 by separating and individually processing spectral
`regions of interest from a larger RF spectrum. More detail
`regions of interest from a larger RF spectrum. More detail
`regarding the digital to analog radio frequency transceiver
`regarding the digital to analog radio frequency transceiver
`(DART) module 132 is provided below.
`(DART) module 132 is provided below.
`0022 FIG. 2 is a block diagram of one embodiment of a
`[0022]
`FIG. 2 is a block diagram of one embodiment of a
`remote unit 106. Remote unit 106 includes a serial radio
`remote unit 106. Remote unit 106 includes a serial radio
`frequency (SeRF) module 220, a digital to analog radio fre
`frequency (SeRF) module 220, a digital to analog radio fre-
`quency transceiver (DART) module 208, a remote DART
`quency transceiver (DART) module 208, a remote DART
`interface board (RDI) 224, and wireless RF components 250
`interface board (RDI) 224, and wireless RF components 250
`that include electronics such as power amplifier, a duplexer, a
`that include electronics such as power amplifier, a duplexer, a
`low noise amplifier and other RF electronics coupled to an
`low noise amplifier and other RF electronics coupled to an
`antenna 212. In alternate embodiments, SeRF modules and
`antenna 212. In alternate embodiments, SeRF modules and
`DART modules described herein are realized using FPGAs,
`DART modules described herein are realized using FPGAs,
`ASICs, digital signal processing (DSP) boards, or similar
`ASICs, digital signal processing (DSP) boards, or similar
`devices.
`devices.
`(0023 DART module 208 provides bi-directional conver
`[0023] DART module 208 provides bi-directional conver-
`sion between analog RF signals and digital sampled RF for
`sion between analog RF signals and digital sampled RF for
`the downlink and uplink transport signals transmitted
`the downlink and uplink transport
`signals transmitted
`between host unit 102 and remote units 106. In the uplink,
`between host unit 102 and remote units 106. In the uplink,
`antenna 212 receives a wireless RF signal from subscriber
`antenna 212 receives a wireless RF signal from subscriber
`208 and passes the RF signal to DART module 208 via RF
`208 and passes the RF signal to DART module 208 via RF
`components 250. DART module 2