US20160142196A1 - Multiple data services over a distributed antenna system - Google Patents

Abstract

Supporting multiple time division duplexed (TDD) based wireless services or frequency division duplexed (FDD) wireless services on a Distributed Antenna System (DAS). TDD based services use a common clock signal to synchronize the components of the DAS for transmission and reception of TDD signals. The DAS can include a GPS receiver which can extract a timing signal from a GPS signal and distribute the timing signal to any and all components of the DAS to enable synchronization of the components for transmitting and receiving TDD signals. The GPS receiver can be part of the interface that connects a TDD based service to the DAS or separate component of the DAS. The DAS can distribute a reference clock signal to all of the components of the DAS in order to maintain zero frequency shift while manipulating with the carrier frequencies of the various wireless services carried by the DAS.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 13/440,173, now U.S. Pat. No. 9,246,557, filed Apr. 5, 2012, which is a continuation of U.S. patent application Ser. No. 12/465,288, filed on May 13, 2009, now U.S. Pat. No. 8,195,224, which claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Patent App. No. 61/052,851, filed on May 13, 2008, the contents of which are relied upon and incorporated herein by reference in their entireties.
• This application is related to the following: U.S. patent application Ser. No. 11/958,062, now U.S. Pat. No. 8,873,585, filed Dec. 17, 2007, Ser. No. 12/016,459, now U.S. Pat. No. 8,121,646, filed Jan. 18, 2008, Ser. No. 12/016,477, filed Jan. 18, 2008, Ser. No. 12/033,226, filed Feb. 19, 2008 and Ser. No. 12/033,252, filed Feb. 19, 2008, which are hereby incorporated by reference in their entireties.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
• Not Applicable
REFERENCE TO MICROFICHE APPENDIX
• Not Applicable
BACKGROUND
• 1. Technical Field of the Invention
• The present invention is directed to Distributed Antenna Systems (DASs) and more particularly, to methods and systems for supporting multiple wireless data services on a DAS.
• Distributed Antenna Systems are used to provide or enhance coverage for wireless services such as Public Safety, Cellular Telephony, Wireless LAN and Medical Telemetry inside buildings and over campuses. The general architecture of a DAS is depicted inFIG. 1.
• A single DAS can serve a single wireless service or a combination of many wireless services operating over multiple bands. With respect to each wireless service served by the DAS, the Aggregation Configuration of the wireless service can be characterized as non-aggregated or aggregated. In a non-aggregated configuration, there is a 1:1 relationship between DAS antennae and Base Transceiver Stations (BTS) or Transmitter/Receiver units for that wireless service. In an aggregated configuration, each BTS unit for a given wireless service is associated with multiple DAS antennae through a hierarchy of aggregation. For example, inFIG. 2, Services A, B, and C are aggregated and Services D1, D2, and D3 are non-aggregated. Services such as D1, D2, and D3 can be aggregated as well. The ability to aggregate services is typically a function of the remote wiring closet equip. Typically, wireless LAN services are arranged in a non-aggregated configuration when using a DAS while cellular services are typically arranged in an aggregated configuration.
• One desired characteristic of a multi-service DAS is that it can use a single antenna to radiate and receive the signals for all services and frequency bands supported by the DAS. Such an antenna would need to cover (i.e. have acceptable performance) in all frequency bands of interest and is commonly referred to as a Broadband Antenna. An example of a supported frequency range for a DAS antenna would be 400 MHz-6 GHz. To provide MIMO based services, a MIMO antenna which includes multiple antenna elements at a common location can be used.
• In referring to the signal flows in DAS systems, the term Downlink signal refers to the signal being transmitted by the source transmitter (e.g. cellular base station) through an antenna to the terminals and the term Uplink signal refers to the signals being transmitted by the terminals which are received by an antenna and flow to the source receiver. Many wireless services have both an uplink and a downlink, but some have only a downlink (e.g. a mobile video broadcast service) or only an uplink (e.g. certain types of medical telemetry).
• 2. Description of the Prior Art
• In addition to providing cellular and other wireless services, these DAS can be used to provide Time Division Duplexed (TDD) based services such as WiFi (IEEE 802.11 and similar standards), ZigBee, Blue Tooth, WiMAX, Advanced Wireless Services (AWS) as well as Frequency Division Duplex (FDD) based services such as WiMAX, Personal Communication Services (PCS) and AWS. When a DAS used to provide these services, either the Main wiring closet or remote wiring closet equipment needs an interface to connect the service network to the DAS. These source interfaces are commonly referred to as a Macro/Micro/Pico/Femto BTS or Access Point (AP) etc. For each additional wireless service that is connected to the DAS a separate, dedicated BTS is needed. Thus, it is difficult to support multiple service networks on a DAS because many expensive BTS devices are needed.
SUMMARY
• One of the benefits of a DAS is that it can allow many different wireless services to be provided over a common physical infrastructure (wiring, wiring closet units, antenna units and other physical components). Thus, once the physical infrastructure is installed, the same physical infrastructure can be used to support additional wireless services and avoids the expense of additional equipment and the installation of that equipment. In addition, operational benefits include lower energy costs and potentially lower maintenance costs.
• Where a DAS has been installed in a facility, it can be desirable to add other wireless services including TDD based services such as WiFi, WiMAX, AWS, ZigBee, Blue Tooth and FDD based services such as WiMAX, PCS and AWS. For each service, an interface can be used to connect the service network to the DAS. In addition, a GPS receiver (or an envelope detector) can be connected to the DAS and used to provide a 1 pulse per second (1 pps) signal to synchronize any and all of the components of the DAS for transmitting and receiving the wireless signals. The 1 pps signal can be distributed over the DAS to any or all of the wiring closet units and to the antenna units to enable them to be synchronized for transmission and reception of the wireless signal.
• In accordance with one embodiment of the invention, the DAS includes a BTS coupled to one or more wiring closet or combining units, each wiring closet unit being coupled to one or more antenna units for providing a wireless service. The antenna units can include passive or active antenna elements or a combination of both. The DAS can be coupled to a first interface which is coupled to a first wireless network to enable the DAS to carry the first wireless network signals over the DAS and the DAS can also be coupled to a second interface which is coupled to a second wireless network to enable the DAS to carry the second wireless network signals over the DAS. All the active elements in the DAS can be monitored or configured by a point to multipoint centralized management system, the management system can transmit and receive point to multipoint signals to and from any of the addressed elements attached to the DAS. The DAS can also coupled to a global positioning system (GPS) receiver and adapted to receive the 1 pps clock signal from one or more GPS satellites and the DAS is adapted and configured to distribute the 1 pps signal to any or all the BTS, wiring closet or combining units and antenna units of the DAS.
• In some embodiments of the invention, the GPS receiver can be integrated with one or more of the interfaces. In alternative embodiments, the GPS receiver can be integrated with the BTS. In alternative embodiments, the GPS receiver can be a separate component connected to any one of the BTS, the first interface, the second interface, the wiring closet units, combining units or the antenna units. In an alternative embodiment, the first interface can include a BTS. In an alternative embodiment, the second interface can include a BTS.
• In accordance with another embodiment of the present invention, the DAS can include a BTS coupled to one or more wiring closet units, each wiring closet unit being coupled to one or more antenna units for providing a first TDD wireless service. The DAS can be coupled to a second interface which is coupled to a second TDD network to enable the DAS to carry the second TDD network signals over the DAS. The DAS can also be coupled to a global positioning system (GPS) receiver and adapted to receive the 1 pps clock signal from one or more GPS satellites and the DAS can be adapted and configured to distribute the 1 pps signal to any or all the BTS, wiring closet units and antenna units of the DAS.
• In some embodiments of the invention, the GPS receiver can be integrated in the BTS. In alternative embodiments, the GPS can be integrated into the second interface. In alternative embodiments, the GPS receiver can be a separate component connected to any one of the BTS, the second interface, the wiring closet units or the antenna units. In an alternative embodiment, the second interface can include a BTS.
• In some embodiments of the invention, the GPS RF signal (e.g., 1.5 Ghz) can be, for example, multiplexed with the other services, and distributed over the DAS without extracting the 1 PPS signal. The GPS RF signal can be de-multiplex and fed to the BTS that includes a GPS receiver or other external GPS receiver at the remote or antenna location.
• In accordance with one embodiment of the invention, instead of a GPS receiver, the DAS can include an envelope detector adapted to extract or recover a 1 pps signal from a TDD signal received by one of the interfaces (for example: Micro cells, Pico cells or Femto cells). The envelope detector can be adapted and configured to extract or recover the 1 pps signal and transfer it to the DAS for distribution to any or all of the components of the DAS including the BTSs, the other interfaces (including other Pico or Femto cells), the wiring closet or combining units, and the antenna units.
• In accordance with one embodiment of the invention, the DAS can be adapted to distribute the 1 pps signal to any and all components of the DAS. The GPS receiver can include or be coupled to a modem or modulator adapted for modulating the 1 pps signal onto a carrier signal and transmitting the carrier signal to any and all components of the DAS. The components of the DAS, including the BTS, the main closet unit, the wiring closet units and the antenna units can include or be coupled to a modem or demodulator adapted for demodulating and extracting the 1 pps signal from the carrier signal and transferring the 1 pps signal to any and all components of the DAS for use in transmitting and receiving TDD signals. The 1 pps signal can be carried on a carrier signal that is distributed over the physical infrastructure of the DAS. Each antenna unit can include a signal processor adapted and configured to regenerate, extract or recover the 1 pps signal from the carrier signal. The carrier signal can be generated at any frequency that the DAS is capable to deliver preferably on non occupied bands, for example, for wired links, using bands below 100 MHz. such as the 20-50 MHz bands and for optical links, using bands over 1 GHz, such as the 1.2-1.7, 2.7-3.0 GHz bands.
• In accordance with one embodiment of the invention, the GPS receiver can be coupled to one or more of the wiring closet units and adapted to transfer the 1 pps signal to one or more of the wiring closet units. The wiring closet units can transmit the 1 pps signal over the (wire and/or optical) cable infrastructure connecting the components of the DAS. The 1 pps signal can be used by the components of the DAS for transmitting and receiving TDD signals.
• In accordance with an embodiment of the invention, the DAS can include a component for generating a reference clock signal, such as an OCXO clock or a pilot clock signal. Typically the reference clock signal will be a 10 Mhz-20 Mhz clock signal. The reference clock signal can be transferred to any and all of the components of over the DAS. The reference clock signal can carried on a 1.5 Ghz-2.0 Ghz carrier signal that is distributed over the physical infrastructure of the DAS. Each component of the DAS can include a Phase Lock Loop (PLL) based component that is adapted and configured to regenerate, extract or recover the reference clock signal from the carrier signal. In some embodiments of the invention, the clock can be delivered at a high frequency (1.5-3 GHz) in order to reduce the potential to introduce noise or interferences to other services and particularly where the communication medium includes an optical communication medium. In some embodiments of the invention, where the communication medium includes a coaxial cable the original clock frequency 10-20 MHz can be used to deliver the reference clock signal.
• One object of the invention is to provide a DAS which can support many wireless services at the same time.
• Another object of the invention is to provide a DAS which can support many wireless services at the same time at a low cost.
• Another object of the invention is to provide a DAS which can support many TDD and FDD based wireless services at the same time.
• Another object of the invention is to provide a DAS which can support many TDD and FDD based wireless services at the same time at a low cost.
• Another object of the invention is to provide a DAS which can support many TDD based wireless services at the same time using the same TDD amplifier where all of the TDD based wireless services can be synchronized to the same TDD timing signal.
• The present invention can be applied to single service and multi-service DAS, in both aggregated and non-aggregated configurations and to both downlink and uplink signal flows.
• These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims.
BRIEF DESCRIPTION OF THE FIGURES
• FIG. 1 is a block diagram of a DAS according to the invention.
• FIG. 2 is a block diagram of a DAS according to the invention.
• FIG. 3 is a block diagram of a DAS according to one aspect of the invention.
• FIG. 4 is a block diagram of a DAS according to one aspect of the invention.
• FIG. 5 is a block diagram of a DAS according to one aspect of the invention.
• FIG. 6 is a block diagram of a DAS according to one aspect of the invention.
• FIG. 7 is a block diagram of an interface according to one aspect of the invention.
• FIG. 8 is a block diagram of a DAS according to one aspect of the invention.
• FIG. 9 is a block diagram of a DAS according to one aspect of the invention.
• FIG. 10 is a block diagram of a DAS according to one aspect of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• The present invention is directed to a method and system for carrying wireless services over a distributed antenna systems (DASs). In accordance with one embodiment of the invention, the DAS includes an interface that connects each wireless service to the DAS and enables the wireless service signals to be transferred through the DAS. The system also includes a GPS receiver (or envelope detector) which is adapted and configured to receive a 1 pulse per second (1 pps) synchronization signal used to control the timing of the wireless signals, such as TDD based signal. The DAS can be adapted and configured to transfer the 1 pps signal to various components of the DAS to enable the DAS to support the transfer of the wireless signals through the DAS. The system can also include a reference clock generator for generating a reference clock signal. The DAS can be adapted and configured to distribute the reference clock signal to any and all components of the DAS. The reference clock signal can be used to synchronize the frequency conversion components of the DAS that change the frequency of the carrier signals (up-shifting or down-shifting the carrier frequency) of the signals carried through the DAS.
• The DAS can also utilize a control channel to send control and configuration information to and receive status information from each managed component of the DAS. The control channel can utilize one or more of the unutilized frequency bands or channels of the DAS to send and receive signals used to carry information between components of the DAS. The control channel can use different frequency bands or channels depending on the communication medium used to convey the signals. For example, the control channel can use a channel in the 80 MHz band over wired media and a channel in the 400 MHz band over optical media. The DAS can use frequency-shift keying (FSK) or amplitude-shift keying (ASK) as the modulation scheme to carry data over the DAS. A DAS management system connected to the main wiring closet or the remote wiring closet can communicate with each managed component of the DAS using a unique address assigned to the component.
• In accordance with the invention, the DAS can provide a single wireless service or multiple wireless services. With respect to systems providing multiple wireless services, the invention can provide a 1 pps timing signal and/or a 10-20 Mhz clock signal to any or all of the components of the DAS that are used to transfer the signals used by wireless services. In some embodiments of the invention, the 1 pps timing signal can be derived from a GPS signal using a GPS receiver. In alternate embodiments of the invention, the 1 pps timing signal can be detected or derived from one or more of the TDD signals using a hardware or software envelope detector system. The invention can use software in its implementation and the method according to the invention can be software controlled and completely automated.
• As shown inFIG. 3, thesystem300 according to the invention can include in aremote wiring closet310, one ormore aggregation units312, one or more wiring closet or combiningunits314, one or more RF/IF interfaces316, and one or more wireless network service interfaces,Sources Dn320. Thesystem300 can also include one or more BTS systems (shown inFIG. 2) providing wireless services, a main closet unit (shown inFIG. 2) for distributing signals corresponding to the wireless services, one or more cable runs340 and one ormore antenna units350. Thesystem300 can also includes a 1 pps timing signal. As shown inFIG. 3, thesystem300 can include aGPS receiver330 which is adapted to receive a GPS signal and extract a 1 pps timing signal, for example, from the 1.5 GHz GPS timing signal (the GPS signal can be obtained from an external antenna directly or from the main closet, multiplexed with the other services). TheGPS receiver330 can be connected to the DAS and the DAS can be adapted to transfer the 1 pps timing signal to any and all components of the DAS. In some embodiments of the invention, the GPS timing signal (either 1 pps or 1.5 GHz) can be connected to that DAS at the main wiring closet and distributed to any and all remotewiring closet units314 for distribution to the antenna units. In other embodiments of the invention, a separate GPS timing signal source can be connected to each remotewiring closet unit314 for distribution to theantenna units350, although all remotewiring closet units314 need not be connected to a GPS timing signal source. Also shown inFIG. 3, thesystem300 can include areference clock source318 which can be used to generate a reference timing signal for up converting or down converting (i.e. changing the frequency of) the carrier signals used to transfer the various services through of the DAS.
• In accordance with one embodiment of the invention, theGPS receiver330 can be connected to one or more of theaggregation units312. Each aggregation unit can received one or more signals corresponding to two or more wireless services and can combine the signals from two or more wireless services for transfer over thecable run340 to one ormore antenna units350. Eachaggregation unit312 connected to the GPS receiver can include a modem or modulator for modulating the 1 pps signal onto a predefined carrier signal which can be transmitted to other components of the DAS. The carrier signal can be, for example, a 100 Mhz carrier signal that is transmitted over the physical infrastructure (i.e., the cables and components) of the DAS. For example, one or more of theantenna units350 can include a modem or demodulator for demodulating the 1 pps timing signal and recovering it from the predefined carrier signal. The 1 pps timing signal can be used by the TDD switching mechanisms, the duplexers and deduplexers of the antenna units to synchronize the operation of some or all of the components of the antenna unit with the TDD signal. Alternatively, the DAS can include additional cabling and physical components for transferring the 1 pps timing signal to other components of the DAS.
• TheGPS receiver330 can also be connected to the network service interfaces,Source Dn320 to provide the 1 pps signal for use in processing the network service signals. Alternatively, theGPS receiver330 can provide the 1.5 Ghz GPS signal directly to theSource Dn320 which can use an internal GPS receiver to extract or recover the 1 pps signal by de-multiplexing the GPS signal provided by the other services that run over the DAS from the main wiring closet. Alternatively, the GPS receiver can be replaced by an envelope detector system which processes or analyzes the TDD signal received bySource Dn320 and extracts or recovers the 1 pps signal. The 1 pps signal determined by the envelope detector system can be further distributed to all the components of the DAS as described herein. Alternatively, the 1.5 GHz or 1 pps GPS timing signal can be provided at the main wiring closet and distributed to each component over the DAS. The components can include a demultiplexer to demultiplex the GPS timing signal from the other services for use by the component.
• WhileFIG. 3 shows theGPS receiver330 as a separate component, theGPS receiver330 can be integrated with theSource Dn320 as shown inFIG. 7. In addition, the 1 pps timing signal can be used to provide a timing signal for many different TDD and other synchronized services. The 1 pps timing signal can be converted to a different frequency and used to synchronize other wireless services that require a synchronized clock signal, including non-TDD based wireless services.
• The reference clock regenerator source318 can include a phase locked loop (PLL) and generate a reference timing signal that can be distributed over the associated DAS components and BTS. The reference timing signal can be, for example, a 10-20 MHz timing signal. The clock can be distributed over the DAS at high frequency, 1-3 GHz, in order to avoid the introduction of noise or interference in other services provided by the DAS.
• FIG. 4 shows asystem400 according to an alternate embodiment of the invention. Similar toFIG. 3,system400 can include one ormore BTS systems402 providing wireless services, amain closet unit408 for distributing signals corresponding to the wireless services to wiring closet units, aremote wiring closet410 including one or more wiring closet units that can combine the signals from two or more wireless services,Source1interface422,Source2interface424, and Source4interface426 which provide interfaces to other wireless services provided by the DAS. Thesystem400 can also include areference clock source404 which produces a reference timing signal. As shown inFIG. 4, thesystem400 can include areference clock source404 which is adapted to produce a predefined reference timing signal which can be fed into the main wiring closet and distributed over DAS. Thesystem400 can also include a GPS receiver (not shown) that can be connected to one or more of the BTS systems or wireless networkservice sources Source1422,Source2424,Source3426 of the DAS and the DAS can be adapted to transfer the 1 pps timing signal to any and all components of the DAS as described herein. The GPS receiver can be a separate component or it can be integrated with one or more of the components of thesystem300. Each of the wirelessservice sources Source1422,Source2424,Source3426 can be connected by wire or by a wireless connection (repeater not shown) to a network that carries the network traffic for that wireless service.
• FIG. 5 shows aDAS500 according to an alternate embodiment of the invention. Similar toFIGS. 3 and 4,DAS500 can include one ormore BTS systems502 providing wireless services, amain closet unit508 for distributing signals corresponding to the wireless services to wiring closet units, aremote wiring closet510 including one or more wiring closet units that can combine the signals from two or more wireless services,Source1522,Source2524, andSource3526 which provide interfaces to other wireless services provided over the DAS. Thesystem500 can also include areference clock source504 which produces a reference timing signal. Thesystem500 can also include a 1 pps timing signal. As shown inFIG. 5, thesystem500 can include aGPS receiver530 which is adapted to receive a GPS signal an extract a 1 pps timing signal. TheGPS receiver530 can be connected to one or more of theSource1,2 or3units522,524,526 of the DAS and the DAS can be adapted to transfer the 1 pps timing signal to any and all components of the DAS as described herein. WhileFIG. 5 shows theGPS receiver530 as a separate component, aGPS receiver530 can be integrated with one or more of theSource1,2,3units522,524, and526 as shown inFIG. 7 below.
• FIG. 6 shows aDAS600 according to an alternate embodiment of the invention. Similar toFIGS. 3, 4 and 5,DAS600 can include one ormore BTS systems602 providing wireless services, amain closet unit608 for distributing signals corresponding to the wireless services to wiring closet units, aremote wiring closet610 including one or more wiring closet units that can combine the signals from two or more wireless services,Source1622,Source2624, andSource3626 which can provide interfaces to other wireless services provided over the DAS. Thesystem600 can also include areference clock source604 which produces a reference timing signal. Thesystem600 also includes a 1 pps timing signal. As shown inFIG. 6, thesystem600 can include aGPS receiver630 which is adapted to receive a GPS signal an extract a 1 pps timing signal. TheGPS receiver630 can be connected to one or more of theantenna units650 of the DAS and theDAS600 can be adapted to transfer the 1 pps timing signal to any and all components of theDAS600 as described herein. WhileFIG. 6 shows theGPS receiver630 as a separate component, aGPS receiver630 can be integrated with one or more of the antenna units.
• FIG. 7 shows a block diagram of a Source orinterface unit700 in accordance with an embodiment of the present invention. Theinterface unit700 can include a radio frequency front end (RF FE)702, areference clock source704, a broad band signal processor (BB Processor706, an Internet Protocol Interface (IP Interface)708 and aCPU712.Interface unit700 can optionally include aGPS receiver730 for receiving GPS signals and producing a 1 pps timing signal. TheRF FE702 can be connected either directly or indirectly to one or more antennae and adapted for transmitting and receiving one or more RF signals. Theinterface unit700 can include one or more different types ofRF FEs702, including a MIMO RF FE, a CDMA RF FE, a TDD RF FE and a GSM RF FE. TheRF FE702 can be connected toBB Processor706. TheBB processor706 can be used to process the signals transmitted and received by theRF FE702. The BB Processor can be connected to theIP Interface708. TheIP interface708 can be used to connect theinterface Unit700 to an IP network which carries the wireless service signals to be transferred over the DAS. TheCPU712 can be connected to theRF FE702, theBB Processor706, theIP Interface708 to monitor and/or control the operation of each of the components of theinterface unit700.
• As shown inFIG. 7, theinterface unit700 can optionally include aGPS receiver730 and be adapted to receive the GPS signals and extract or recover the 1 pps timing signal. TheGPS receiver730 can be connected to a separate antenna and be adapted to provide the 1 pps timing signal to an external other components of theinterface unit700 as well as components of the DAS.
• As shown inFIG. 7, theinterface unit700 can include areference clock source704. Thereference clock source704 can be used to provide a reference timing signal for converting baseband and intermediate frequency signals to or from radio frequency signals as they are transmitted or received by the components of the DAS.Reference clock source704 can be a precision clock circuit that includes a phase lock loop. Alternatively, thereference clock source704 can be a component that is connected to the DAS and receives the reference clock signal distributed over the DAS and extracts the reference timing signal for use by theinterface unit700.
• FIG. 8 shows aDAS800 according to an alternate embodiment of the invention. Similar toFIGS. 3, 4, 5 and 6,DAS800 can include one or more BTS systems providing wireless sources, a main closet unit for distributing signals to wiring closet units, aremote wiring closet810 including one or more wiring closet or combiningunits814, andSource Dn820, which can provide interfaces to other wireless services provided over the DAS. Thesystem800 can also include areference clock source818 which produces a reference timing signal. TheDAS800 also includes a 1 pps timing signal. As shown inFIG. 8, thesystem800 can include adetector832 which is adapted to receive a TDD signal and extract a 1 pps timing signal. Thedetector832 can be connected to one or more of the Source Dn units,820 of theDAS800, one or more of the wiring closet or combiningunits814 of theDAS800 or one or more of theantenna units850 of theDAS800. TheDAS800 can be adapted to transfer the 1 pps timing signal to any and all components of theDAS800 as described herein. WhileFIG. 8 shows thedetector832 as a separate component, adetector832 can be integrated with one or more of theSource Dn units820 of theDAS800, one or more of thewiring closet units814 of theDAS800 or one or more of theantenna units850. The input to theenvelope detector832 can be any one of theSource Dn units820 and that input will serve as the primary source of the timing signal from which all of the other components and TDD sources will be synchronized.
• In operation of one embodiment of the invention, one or more of the Source interface units822,824,826 receives one or more TDD signals and thedetector832 processes one or more of the TDD signals to determine the timeslot boundaries and determine a timing signal. In one embodiment of the invention, the timing signal is a 1 pps timing signal. In one embodiment of the invention, thedetector832 can include an envelope detector for detecting the timing envelope of one or more of the TDD signals.
• FIG. 9 shows aDAS900 according to an alternative embodiment of the invention. Similar toFIGS. 3-8,DAS900 can include aremote wiring closet910 including one or more wiring closet or combining units (not shown) and other components of the DAS.DAS900 can include a low cost Micro, Pico orFemto Cell920 and anantenna unit950 that includes an analogremote radio head960. Similar to interface700, the Micro, Pico orFemto Cell920 can include a baseband to intermediate frequency signal (BB-IF)converter902, a referenceclock input PLL904, abaseband processor906, anIP interface908, aCPU912 and a GPS receiver (or 1 pps source)930. The BB-IF signal converter902 converts baseband signal received over theIP interface908 to intermediate frequency signals for transmission over the DAS to theantenna units950 and converts the IF signals received from theantenna units950 to baseband signals for transmission over the DAS and through theIP interface908 to the supporting service network. standard BB toRF chipset964. The BB-IF signal converter902 can use the same reference clock signal to synchronize the conversion from BB to IF and from IF to BB. The BB-IF signal converter902 can be connected toBB Processor906. TheBB processor906 can be used to process the baseband signals sent to and received from the BB-IF signal converter902. The BB Processor can be connected to theIP Interface908. TheIP interface908 can be used to connect thecell920 to an IP network which carries the wireless service signals to be transferred over the DAS. TheCPU912 can be connected to the BB-IF signal converter902, theBB Processor906, theIP Interface908 to monitor and/or control the operation of each of the components of thecell920. The cell can support multiple sections to allow for more users or network connections as well as to provide for multiple MIMO streams.
• As shown inFIG. 9, theDAS900 can includes include one ormore antenna units950 that include one or more analog remote radio heads (ARRH)960. EachARRH960 can include one or more multiplexed/de multiplexed IF-BB signal converters962, one or more BB-RF signal converters964 and a input reference clock PLL regenerator952 Theremote closet910 can provide the same reference clock to both referenceclock PLL regenerators952,904. In some embodiments of the invention, the reference clock signal can be used without further processing, such as by a reference clock PLL regenerator. The IF-BB signal converters962 can be used to convert the IF signals used to carry the individual wireless services over theDAS900 to theantenna unit950 to BB signals and the BB-RF signal converters964 can be used to convert the BB signals to RF signals for transmission by the antenna to the wireless terminal devices. In addition, the BB-RF signal converters964 can be used to convert the RF signals received from the wireless terminal devices to BB signals and the IF-BB signal converters962 can be used to convert the BB signals to IF signals used to carry the wireless signals through theDAS900 to Source BTS (not shown). The BB-IF signal converters902, the IF-BB signal converters962 and the BB-RF signal converters964 can include standard chipsets that are commercially available from for example MAXIM Integrated Products, Sunnyvale, Calif. and Analog Devices, Inc., Norwood, Mass. In addition, the bidirectional BB-IF902 and the IF-BB962 convertors can have the capability to provide automatic gain compensation to compensate for varying cable losses within the DAS. In addition, the BB receiver of the BB-IF and IF-BB signal converters can provide additional capabilities including DC offset compensation between the I,Q components of the signals and a tunable Low Pass Filter (LPF) to improve the channel separation from other services and provide, per channel, noise level filtering. TheARRH960 can use the reference timing signal provided by the reference clock source952 to synchronize the conversion of the signals. The reference clock source952 can be a clock signal re-generator component that re-generates the reference clock signal that is distributed through theDAS900. The reference clock signal can be generated by a primary referenceclock signal generator918 connected to the main wiring closet or theremote wiring closet910 and distributed over theDAS900 using one or more of the unused frequency bands or channels carried by theDAS900. Alternatively, the reference clock signal can be generated by a component of the Pico orFemto Cell920 and transferred to theremote wiring closet910 and distributed to the other components of theDAS900, including theantenna units950, other Pico or Femto Cells and the main wiring closet.
• TheDAS900 can also include a 1 pps signal. In one embodiment of the invention, the 1 pps signal can be generated by GPS receiver (or an envelope detector)930 as part of the Micro, Pico orFemto Cell920 and distributed over theDAS900 toantenna unit950 where it is received by acomponent932 of theantenna unit950 that regenerates, extracts or recovers the 1 pps signal from a signal received from theDAS900. The 1 pps signal can distributed over theDAS900 using one or more unused frequency bands or channels carried by theDAS900. The 1pps source930 and932 can be a component that derives the 1 ppm signal from the 1.5 GHz GPS signal received from an antenna or over the DAS, or alternatively, the 1pps source930 and932 can be a component that includes a synthesizer and/or a phase lock loop that regenerates, extracts or recovers the 1 pps signal from a received signal distributed over theDAS900. In an alternative embodiment, the GPS receiver (or envelope detector)932 can be located with theantenna unit950 and the 1 pps signal or a signal carrying the 1 pps signal can be sent over theDAS900 to the other components of the DAS including Pico orFemto Cell920.
• FIG. 10 shows aDAS1000 according to an alternative embodiment of the invention. Similar toFIG. 9,DAS1000 can include aremote wiring closet1010 including one or more wiring closet or combining units (not shown) and other components of the DAS.DAS1000 can include a low cost Pico orFemto Cell1020 and anantenna unit1050 that includes an analogremote radio head1060. Similar to interface920 and700, the low cost Micro, Pico orFemto Cell1020 can include a baseband to radiofrequency signal converter1002, a reference clock source1004, abaseband processor1006, anIP interface1008, aCPU1012 and a GPS receiver (or 1 pps source)1030. The BB-RF signal converter1002 converts the baseband signal received over theIP interface1008 to RF signals for transmission over the DAS to theantenna units1050 and converts the RF signals received from theantenna units1050 to baseband signals for transmission through the IP interface to the supporting service network. The BB-RF signal converter1002 can use the reference clock signal to synchronize the conversion from BB to RF and RF to BB. The BB-RF signal converter1002 can be connected toBB Processor1006. TheBB processor1006 can be used to process the baseband signals sent to and received from the BB-RF signal converter1002. TheBB Processor1006 can be connected to theIP Interface1008. TheIP interface1008 can be used to connect thecell1020 to an IP network which carries the wireless service signals to be transferred over the DAS. TheCPU1012 can be connected to the BB-RF signal converter1002, theBB Processor1006, theIP Interface1008 to monitor and/or control the operation of each of the components of thecell1020. The cell can support multiple sections to allow for more users or network connections as well as to provide for multiple MIMO streams.
• In the embodiment shown inFIG. 10, theremote closet1010 can include one or more bidirectional multiplexed/de-multiplexed RF toIF signal converter1016 that can be used to convert the RF signals received from theCell1020 to IF signals for transmission to the ARRH1060 (update the drawing) ofantenna unit1050 and to convert IF signals received from theARRH1060 of theantenna unit1050 to RF signals for transmission to theCell1020. In addition the bidirectional RF to IF1016 and the IF toRF1062 convertors can have the capability to provide automatic gain compensation to compensate for varying cable losses in theDAS1000. This embodiment of the invention would allow the use of conventional Micro, Pico andFemto Cells1020 to be connected to theDAS1000.
• Similar toFIG. 9, the 1 pps signal provided by either a GPS receiver (or an envelope detector)1030 or a reference clock source connected to the main closet or theremote closet1010 can be distributed over theDAS1000 to thePLL1052 in theantenna unit1050
• It is noted that in various drawing figures, more than one cable appears to connect the components of the DAS, for example inFIGS. 9 and 10, multiple connections are shown between theremote closet910,1010 and theCell920,1020 orantenna unit950,1050. In accordance with the invention, only one physical cable is needed to convey the described signals, although in alternative embodiments of the invention more than one cable can be used. In addition, the cables disclose herein can any medium that can be used to transfer a signal from one location to another and that combinations of cable types can be used. The cables can be electrical or optical or radio frequency conducting media.
• The 1 pps signal can be converted or encoded onto another signal that is transferred through the DAS on the same cable or medium that is used to transfer the wireless services. In accordance with one embodiment of the invention, the 1 pps signal can be converted or encoded onto any unused frequency that can be transferred by the DAS. In one embodiment, the 1 pps signal is converted to a 20-50 MHz signal for transmission through the metallic cable media of the DAS and converted to 1.5-1.6 GHz for transmission through the optical cable media of the DAS. In general, the 1 pps signal can be carried on any band below 100 MHz over metallic cable media and can be carried on any band above 1.0 GHz over optical cable media.
• The reference clock signal can be converted or encoded onto another signal that is transferred through the DAS on the same cable or medium that is used to transfer the wireless services. In accordance with one embodiment of the invention, the reference clock signal can be, for example, an Oven Controlled Crystal Oscillator (OCXO) at 10-20 Mhz signal that is converted or encoded onto any unused frequency that can be transferred by the DAS. In one embodiment, the reference clock signal is converted to a 1.5-2.0 Ghz signal for transmission through the DAS.
• Other embodiments are within the scope and spirit of the invention. For example, due to the nature of software, functions described above can be implemented using software, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
• Further, while the description above refers to the invention, the description may include more than one invention.

Claims (13)

What is claimed is:

1. A wireless system, comprising:

at least one wireless source coupled to at least one wiring unit, the at least one wireless source providing signals corresponding to a first wireless service over the wireless system;

a plurality of cable runs each including electrical radio frequency conducting media and connecting the at least one wiring unit to a plurality of antenna units, each antenna unit having at least one duplexer and at least one deduplexer, the cable runs connecting the at least one wiring unit to at least one of the antenna units and transferring signals corresponding to at least one wireless service between the at least one wiring unit and at least one of the antenna units;

an interface adapted to connect a second wireless source providing a second wireless service to the wireless system and transfer signals corresponding to the second wireless service over the wireless system; and

an envelope detector connected to the wireless system and adapted to receive a signal corresponding to the wireless service and to produce a timing signal, the timing signal being transferred over the wireless system.

2. The wireless system ofclaim 1, further comprising the second wireless source connected to the interface.

3. The wireless system ofclaim 2, wherein the envelope detector is connected to the second wireless source and adapted to transfer the timing signal to the interface.

4. The wireless system ofclaim 3, wherein the timing signal is transferred over the wireless system to at least one of the antenna units and used by the antenna unit to synchronize an operation of the antenna unit.

5. The wireless system ofclaim 2, wherein the timing signal is modulated onto a carrier signal and transferred over the wireless system using the carrier signal.

6. A wireless system, comprising:

a first combining unit;

a plurality of cable runs each including electrical radio frequency conducting media and connecting the first combining unit to a plurality of antenna units, each antenna unit having at least one duplexer and at least one deduplexer;

the first combining unit including a base station connection capable of connecting a base station to the first combining unit, the first combining unit being capable of transferring signals corresponding to a first wireless service between the base station and at least one of the cable runs;

at least one wireless service access point connected to the first combining unit, the first combining unit being capable of transferring signals corresponding to a second wireless service between the at least one wireless access point and at least one of the cable runs;

a first interface module connected to the wireless service access point and capable of converting a control signal sent from the wireless service access point to an intermediate frequency (IF) control signal and transferring the IF control signal between the wireless service access point and the first combining unit; and

a second combining unit connected to at least one of the cable runs and capable of receiving the IF control signal and converting the IF control signal back to the control signal and transferring the control signal to at least one of the antenna units of the wireless system.

7. The wireless system ofclaim 6, further comprising a reference clock signal generator connected to the first combining unit and capable of generating a reference clock signal, the first combining unit being capable of receiving the reference clock signal and transmitting the reference clock signal over at least one of the cable runs to at least one of the antenna units.

8. The wireless system ofclaim 7, wherein the first combining unit is capable of transferring the IF control signal between the first interface module and at least one of the cable runs, and uses the reference clock signal to convert a signal received from the access point corresponding to the second wireless service to an intermediate frequency signal and transfers the intermediate frequency signal over at least one of the cable runs to at least one of the antenna units.

9. A wireless system comprising:

at least one wiring unit;

a first wireless source connected to the at least one wiring unit, the first wireless source providing signals corresponding to a first wireless service over the wireless system;

a plurality of antenna units, each antenna unit having at least one duplexer and at least one deduplexer;

a plurality of cable runs each including electrical radio frequency conducting media connecting the at least one wiring unit to the plurality of antenna units and transferring signals corresponding to at least one wireless service between the at least one wiring unit and the antenna units;

a second wireless source;

an interface adapted to connect the second wireless source to provide a second wireless service to the wireless system and transfer signals corresponding to the second wireless service over the wireless system; and

an envelope detector system adapted to produce a timing signal, the timing signal being transferred over the wireless system, wherein the envelope detector system is connected to the second wireless source and adapted to transfer the timing signal to the interface.

10. A wireless system comprising:

at least one wireless source connected to a main wiring closet unit, said at least one wireless source producing signals corresponding to a first wireless service over the wireless system;

a remote wiring closet unit connected to the main wiring closet unit, the remote wiring closet unit including at least one combining unit, the at least one combining unit being adapted to transfer signals corresponding to two or more wireless services between the at least one wireless source and at least one cable run to an antenna unit;

at least one cable run connecting the at least one combining unit to at least one antenna unit to transfer the signals corresponding to the first wireless service over the wireless system;

an interface adapted to connect a second wireless service to the wireless system and transfer signals corresponding to the second wireless service over the wireless system; and

an envelope detector system connected to the wireless system and adapted to produce and send a timing signal over the wireless system.

11. A wireless system according toclaim 10, wherein the interface is connected to the remote wiring closet unit and adapted to transfer signals corresponding to the second wireless service over the DAS.

12. A wireless system according toclaim 11, wherein the interface is connected to the at least one antenna unit and adapted to transfer signals corresponding to the second wireless service over the at least one antenna unit.

13. A wireless system comprising:

at least one wireless source coupled to at least one wiring closet unit, said at least one wireless source providing signals corresponding to a first wireless service over the wireless system;

at least one antenna unit comprising at least one duplexer and at least one deduplexer;

at least one cable run connecting the at least one wiring closet unit to at the least one antenna unit and transferring signals corresponding to at least one wireless service between the at least one wiring closet unit and at least one antenna unit;

an interface adapted to connect a second wireless source providing a second wireless service to the wireless system and transfer signals corresponding to the second wireless service over the wireless system; and

an envelope detector connected to the wireless system and adapted to receive a signal corresponding to a wireless service and produce a timing signal, said timing signal being transferred over the wireless system, wherein

the timing signal is modulated onto a carrier signal and transferred over the wireless system to the at least one antenna unit using the carrier signal, and used by the antenna unit to synchronize an operation of the antenna unit.

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