# Patent

## Title
Sectorization in distributed antenna systems, and related components and methods

## Abstract

Distributed antenna systems in which the distributed antenna systems can be sectorized. Radio bands distributed by the distributed antenna systems are allocated to one or more sectors. The antenna units in the distributed antenna systems are also allocated to one or more sectors. In this manner, only radio frequency (RF) communications signals in the radio band(s) allocated to given sector(s) are distributed the antenna unit allocated to the same sector(s). The bandwidth capacity of the antenna unit is split among the radio band(s) allocated to sector(s) allocated to the antenna unit. The sectorization of the radio band(s) and the antenna units can be configured and/or altered based on capacity needs for given radio bands in antenna coverage areas provide by the antenna units.

## Background
PRIORITY APPLICATION
This application is a continuation of U.S. patent application Ser. No. 12/914,585 filed on Oct. 28, 2010, the content of which is relied upon and incorporated herein by reference in its entirety, and the benefit of priority under U.S.C. §120 is hereby claimed.
RELATED APPLICATIONS
The present application is related to U.S. Provisional Patent Application No. 61/330,383, filed on May 2, 2010, to U.S. Provisional Patent Application No. 61/230,463, filed on Jul. 31, 2009, and to U.S. Provisional Patent Application No. 61/230,472, filed on Jul. 31, 2009, which are incorporated herein by reference in their entireties.


BACKGROUND
1. Field of the Disclosure
The technology of the disclosure relates to distributed antenna systems for distributing radio frequency (RF) signals to remote antenna units.
2. Technical Background
Wireless communication is rapidly growing, with ever-increasing demands for high-speed mobile data communication. As an example, so-called “wireless fidelity” or “WiFi” systems and wireless local area networks (WLANs) are being deployed in many different types of areas (e.g., coffee shops, airports, libraries, etc.). Distributed antenna systems communicate with wireless devices called “clients,” which must reside within the wireless range or “cell coverage area” in order to communicate with an access point device.
One approach to deploying a distributed antenna system involves the use of radio frequency (RF) antenna coverage areas, also referred to as “antenna coverage areas.” The antenna coverage areas are provided by remote antenna units in the distributed antenna system. Remote antenna units can provide antenna coverage areas having radii in the range from a few meters up to twenty (20) meters as an example. If the antenna coverage areas provided each cover a small area, there are typically only a few users (clients) per antenna coverage area. This allows for minimizing the amount of RF bandwidth shared among the wireless system users. It may be desirable to provide antenna coverage areas in a building or other facility to provide indoor distributed antenna system access to clients within the building or facility. It may also be desirable to employ optical fiber to distribute RF communications signals to provide an optical fiber-based distributed antenna system. Distribution of RF communications signals over optical fiber can include Radio-over-Fiber (RoF) distribution. Benefits of optical fiber include increased bandwidth.
Remote antenna units in a distributed antenna system can be configured to distribute RF communication signals in multiple radio bands (i.e., frequencies or ranges of frequencies), as opposed to a single radio band. Distributing RF communications signals in multiple radio bands in an antenna coverage area increases flexibility of the distributed antenna system. In this scenario, client devices configured to communicate in different radio bands can be supported in a given antenna coverage area provided by the remote antenna unit. However, providing remote antenna units that support multiple radio bands can also limit capacity in the distributed antenna system. The bandwidth of the remote antenna unit is split among the multiple radio bands thus reducing the capacity of each supported radio band in a given antenna coverage area.
To offset a reduction in capacity in remote antenna units supporting multiple radio bands, additional remote antenna units could be provided. The remote antenna units could be co-located and each configured to support only one of the radio bands. However, providing additional remote antenna units increases the cost of the distributed antenna system. Further, additional head-end equipment may be required to be deployed to support the additional remote antenna units. Providing additional remote antenna units to provide additional capacity may be delayed after initial installation and provided as needed, but higher installation costs may be associated with retrofitting an existing installation with additional remote antenna units.
SUMMARY OF THE DETAILED DESCRIPTION
Embodiments disclosed in the detailed description include providing sectorization in distributed antenna systems, and related components and methods. As one non-limiting example, the distributed antenna systems may be optical fiber-based distributed antenna systems. The antenna units in the distributed antenna systems can be sectorized. In this regard, one or more radio bands distributed by the distributed antenna systems can be allocated to one or more sectors. The antenna units in the distributed antenna systems are also allocated to one or more sectors. In this manner, only radio frequency (RF) communications signals in the radio band(s) allocated to given sector(s) are distributed to the antenna unit allocated to the same sector(s). The bandwidth capacity of the antenna unit is split among the radio band(s) allocated to sector(s) allocated to the antenna unit. The sectorization of the radio band(s) and the antenna units can be configured and/or altered based on capacity needs for given radio bands in antenna coverage areas provide by the antenna units.
In one embodiment, a head-end apparatus or equipment configured to distribute radio bands in one or more sectors among a plurality of sectors in a distributed antenna system is provided. The head end equipment includes a plurality of radio interfaces each configured to split a received downlink electrical RF communications signal into a plurality of downlink electrical RF communications signals. Each of the plurality of radio interfaces is also configured to control providing each of the split plurality of downlink electrical RF communications signals to one or more sectors among a plurality of sectors in a distributed antenna system configured for the radio interface. A plurality of optical interfaces is also provided and each configured to receive the split plurality of downlink electrical RF communications signals from the plurality of radio interfaces. Each of the plurality of optical interfaces is also configured to control for which sectors among the plurality of sectors configured for the optical interface the received split plurality of downlink electrical RF communications signals are provided to one or more remote antenna units (RAUs) communicatively coupled to the optical interface. Each of the plurality of optical interfaces is also configured to convert the received split plurality of downlink electrical RF communications signals into a plurality of downlink optical RF communications signals.
The head end equipment may also include components to sectorize uplink RF communications signals as well. In this regard, in another embodiment, each of the plurality of optical interfaces provided in the head end equipment is further configured to split a received uplink optical RF communications signal into a plurality of uplink optical RF communications signals. Each of the plurality of optical interfaces is also configured to control providing each of the split plurality of uplink optical RF communications signals to the one or more sectors among a plurality of sectors configured for the optical interface. Each of the plurality of optical interfaces is also configured to convert the received split plurality of uplink optical RF communications signals into a plurality of uplink electrical RF communications signals. Each of the plurality of radio interfaces provided in the head end equipment is further configured to receive the plurality of uplink electrical RF communications signals from the plurality of optical interfaces. Each of the plurality of radio interfaces is also configured to control for which sectors among the plurality of sectors configured for the radio interface the received plurality of uplink electrical RF communications signals are provided to one or more carriers communicatively coupled to the radio interface.
In another embodiment, a method of distributing radio bands in one or more sectors among a plurality of sectors in a distributed antenna system is provided. The method includes splitting a received downlink electrical RF communications signal into a plurality of downlink electrical RF communications signals. The method also includes providing each of the split plurality of downlink electrical RF communications signals to one or more sectors among a plurality of sectors in a distributed antenna system. The method also includes receiving the split plurality of downlink electrical RF communications signals. The method also includes controlling for which sectors among the plurality of sectors the received split plurality of downlink electrical RF communications signals are provided to one or more RAUs communicatively. The method also includes converting the received split plurality of downlink electrical RF communications signals into a plurality of downlink optical RF communications signals.
In another embodiment, a radio interface configured to distribute radio bands in unique sectors among a plurality of sectors in a distributed antenna system is provided. The radio interface includes a downlink interface configured to receive a downlink RF communications signal. The radio interface also includes a downlink splitter configured to split the downlink RF communications signal into a plurality of downlink RF communications signals. The radio interface also includes a plurality of downlink sector switches each assigned to a unique sector among a plurality of sectors in a distributed antenna system. Each of the plurality of downlink sector switches is configured to receive a downlink RF communications signal among the plurality of downlink RF communications signals from the downlink splitter, and control whether the received downlink RF communications signal is distributed to the unique sector assigned to the sector switch. The radio interface may also include components to sectorize uplink RF communications signals as well.
In another embodiment, an optical interface configured to distribute radio bands in unique sectors among a plurality of sectors in a distributed antenna system is provided. The optical interface includes a downlink interface configured to receive a plurality of downlink electrical RF communications signals each assigned to a unique sector among a plurality of sectors in a distributed antenna system. The optical interface also includes a plurality of downlink sector switches each assigned to a unique sector in the distributed antenna system. Each of the plurality of downlink sector switches is configured to receive a downlink electrical RF communications signal among the plurality of downlink electrical RF communications signals for the unique sector assigned to the sector switch. Each of the plurality of downlink sector switches is also configured to control whether the received downlink electrical RF communications signal is distributed to the unique sector assigned to the sector switch. A plurality of downlink electrical-to-optical (E/O) converters are provided in the optical interface and each configured to receive the downlink electrical RF communications signal from a sector switch among the plurality of sector switches, and convert the received downlink electrical RF communications signal into a downlink optical RF communications signal. The optical interface may also include components to sectorize uplink RF communications signals as well.
Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description that follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.



BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic diagram of an exemplary optical fiber-based distributed antenna system;
FIG. 2 is a more detailed schematic diagram of exemplary head end equipment and a remote antenna unit (RAU) that can be deployed in the optical fiber-based distributed antenna system of FIG. 1;
FIG. 3 is a partially schematic cut-away diagram of an exemplary building infrastructure in which the optical fiber-based distributed antenna system in FIG. 1 can be employed;
FIG. 4 is an schematic diagram illustrating exemplary sectorization in a distributed antenna system;
FIG. 5 is a schematic diagram of another exemplary optical fiber-based distributed antenna system;
FIG. 6 is a schematic diagram of exemplary head end equipment provided in a distributed antenna system supporting configurable sectorization in the distributed antenna system;
FIG. 7 is an exemplary sectorization table provided in head end equipment to store a default and/or user-configured sectorization for a distributed antenna system;
FIG. 8 is a schematic diagram of exemplary head end equipment provided in a distributed antenna system and configured with expansion ports to support additional remote antenna units, wherein one expansion port supports an optical interface unit (OIU) supporting a single sector;
FIG. 9 is a schematic diagram of exemplary head end equipment provided in a distributed antenna system and configured with expansion ports to support additional remote antenna units, wherein multiple expansion ports support an OIU supporting multiple sectors;
FIG. 10 is a schematic diagram of an exemplary radio distribution matrix provided for a head end equipment to allow multiple carriers to utilize common optical interface modules (OIMs) and RAUs to distribute communications signals in a distributed antenna system
FIG. 11 is a schematic diagram of providing an expanded number of sectors in a distributed antenna system; and
FIG. 12 is a schematic diagram of exemplary head end equipment provided in a distributed antenna system supporting sectorization and multiple-input, multiple-output (MIMO) processing in a distributed antenna system.



DETAILED DESCRIPTION
Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all embodiments are shown. Indeed, the concepts may be embodied in many different forms and should not be construed as limiting herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.
Embodiments disclosed in the detailed description include providing sectorization in distributed antenna systems, and related components and methods. As one non-limiting example, the distributed antenna systems may be optical fiber-based distributed antenna systems. The antenna units in the distributed antenna systems can be sectorized. In this regard, one or more radio bands distributed by the distributed antenna systems can be allocated to one or more sectors. The antenna units in the distributed antenna systems are also allocated to one or more sectors. In this manner, only radio frequency (RF) communications signals in the radio band(s) allocated to given sector(s) are distributed to the antenna unit allocated to the same sector(s). The bandwidth capacity of the antenna unit is split among the radio band(s) allocated to sector(s) allocated to the antenna unit. The sectorization of the radio band(s) and the antenna units can be configured and/or altered based on capacity needs for given radio bands in antenna coverage areas provide by the antenna units.
Before discussing distributed antenna systems and related components and methods that support sectorization starting at FIG. 4, FIGS. 1-3 are provided and first discussed below. FIGS. 1-3 provide examples of distributed antenna systems that do not include sectorization support, but can be configured to provide sectorization support, including according to the embodiments described herein.
FIG. 1 is a schematic diagram of an embodiment of an optical fiber-based distributed antenna system. In this embodiment, the system is an optical fiber-based distributed antenna system 10 that is configured to create one or more antenna coverage areas for establishing communications with wireless client devices located in the RF range of the antenna coverage areas. The optical fiber-based distributed antenna system 10 provides RF communications services (e.g., cellular services). In this embodiment, the optical fiber-based distributed antenna system 10 includes head end equipment in the form of a head-end unit (HEU) 12, one or more remote antenna units (RAUs) 14, and an optical fiber 16 that optically couples the HEU 12 to the RAU 14 in this example. The HEU 12 is configured to receive communications over downlink electrical RF communications signals 18D from a source or sources, such as a network or carrier as examples, and provide such communications to the RAU 14. The HEU 12 is also configured to return communications received from the RAU 14, via uplink electrical RF communications signals 18U, back to the source or sources. In this regard in this embodiment, the optical fiber 16 includes at least one downlink optical fiber 16D to carry signals communicated from the HEU 12 to the RAU 14 and at least one uplink optical fiber 16U to carry signals communicated from the RAU 14 back to the HEU 12. One downlink optical fiber 16D and one uplink optical fiber 16U could be provided to support multiple channels each using wavelength-division multiplexing (WDM), as discussed in U.S. patent application Ser. No. 12/892,424 entitled “Providing Digital Data Services in Optical Fiber-Based Distributed Radio Frequency (RF) Communications Systems, And Related Components and Methods,” incorporated herein by reference in its entirety. Other options for WDM and frequency-division multiplexing (FDM) are also disclosed in U.S. patent application Ser. No. 12/892,424, any of which can be employed in any of the embodiments disclosed herein.
The optical fiber-based distributed antenna system 10 has an antenna coverage area 20 that can be substantially centered about the RAU 14. The antenna coverage area 20 of the RAU 14 forms an RF coverage area 21. The HEU 12 is adapted to perform or to facilitate any one of a number of wireless applications, including but not limited to Radio-over-Fiber (RoF), radio frequency identification (RFID), wireless local-area network (WLAN) communication, public safety, cellular, telemetry, and other mobile or fixed services. Shown within the antenna coverage area 20 is a client device 24 in the form of a mobile device as an example, which may be a cellular telephone as an example. The client device 24 can be any device that is capable of receiving RF communication signals. The client device 24 includes an antenna 26 (e.g., a wireless card) adapted to receive and/or send electromagnetic RF communications signals.
With continuing reference to FIG. 1, to communicate the electrical RF communications signals over the downlink optical fiber 16D to the RAU 14, to in turn be communicated to the client device 24 in the antenna coverage area 20 formed by the RAU 14, the HEU 12 includes an electrical-to-optical (E/O) converter 28. The E/O converter 28 converts the downlink electrical RF communications signals 18D to downlink optical RF communications signals 22D to be communicated over the downlink optical fiber 16D. The RAU 14 includes an optical-to-electrical (O/E) converter 30 to convert received downlink optical RF communications signals 22D back to electrical RF communications signals to be communicated wirelessly through an antenna 32 of the RAU 14 to client devices 24 located in the antenna coverage area 20.
Similarly, the antenna 32 is also configured to receive wireless RF communications from client devices 24 in the antenna coverage area 20. In this regard, the antenna 32 receives wireless RF communications from client devices 24 and communicates electrical RF communications signals representing the wireless RF communications to an E/O converter 34 in the RAU 14. The E/O converter 34 converts the electrical RF communications signals into uplink optical RF communications signals 22U to be communicated over the uplink optical fiber 16U. An O/E converter 36 provided in the HEU 12 converts the uplink optical RF communications signals 22U into uplink electrical RF communications signals, which can then be communicated as uplink electrical RF communications signals 18U back to a network or other source. The HEU 12 in this embodiment is not able to distinguish the location of the client devices 24 in this embodiment. The client device 24 could be in the range of any antenna coverage area 20 formed by an RAU 14.
FIG. 2 is a more detailed schematic diagram of the exemplary optical fiber-based distributed antenna system 10 of FIG. 1 that provides electrical RF service signals for a particular RF service or application. In an exemplary embodiment, the HEU 12 includes a service unit 37 that provides electrical RF service signals by passing (or conditioning and then passing) such signals from one or more outside networks 38 via a network link 39. In a particular example embodiment, this includes providing WLAN signal distribution as specified in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, i.e., in the frequency range from 2.4 to 2.5 GigaHertz (GHz) and from 5.0 to 6.0 GHz. Any other electrical RF communications signal frequencies are possible. In another exemplary embodiment, the service unit 37 provides electrical RF service signals by generating the signals directly. In another exemplary embodiment, the service unit 37 coordinates the delivery of the electrical RF service signals between client devices 24 within the antenna coverage area 20.
With continuing reference to FIG. 2, the service unit 37 is electrically coupled to the E/O converter 28 that receives the downlink electrical RF communications signals 18D from the service unit 37 and converts them to corresponding downlink optical RF communications signals 22D. In an exemplary embodiment, the E/O converter 28 includes a laser suitable for delivering sufficient dynamic range for the RoF applications described herein, and optionally includes a laser driver/amplifier electrically coupled to the laser. Examples of suitable lasers for the E/O converter 28 include, but are not limited to, laser diodes, distributed feedback (DFB) lasers, Fabry-Perot (FP) lasers, and vertical cavity surface emitting lasers (VCSELs).
With continuing reference to FIG. 2, the HEU 12 also includes the O/E converter 36, which is electrically coupled to the service unit 37. The O/E converter 36 receives the uplink optical RF communications signals 22U and converts them to corresponding uplink electrical RF communications signals 18U. In an example embodiment, the O/E converter 36 is a photodetector, or a photodetector electrically coupled to a linear amplifier. The E/O converter 28 and the O/E converter 36 constitute a “converter pair” 35, as illustrated in FIG. 2.
In accordance with an exemplary embodiment, the service unit 37 in the HEU 12 can include an RF communications signal conditioner unit 40 for conditioning the downlink electrical RF communications signals 18D and the uplink electrical RF communications signals 18U, respectively. The service unit 37 can include a digital signal processing unit (“digital signal processor”) 42 for providing to the RF communications signal conditioner unit 40 an electrical signal that is modulated onto an RF carrier to generate a desired downlink electrical RF communications signal 18D. The digital signal processor 42 is also configured to process a demodulation signal provided by the demodulation of the uplink electrical RF communications signal 18U by the RF communications signal conditioner unit 40. The service unit 37 in the HEU 12 can also include an optional central processing unit (CPU) 44 for processing data and otherwise performing logic and computing operations, and a memory unit 46 for storing data, such as data to be transmitted over a WLAN or other network for example.
With continuing reference to FIG. 2, the RAU 14 also includes a converter pair 48 comprising the O/E converter 30 and the E/O converter 34. The O/E converter 30 converts the received downlink optical RF communications signals 22D from the HEU 12 back into downlink electrical RF communications signals 50D. The E/O converter 34 converts uplink electrical RF communications signals 50U received from the client device 24 into the uplink optical RF communications signals 22U to be communicated to the HEU 12. The O/E converter 30 and the E/O converter 34 are electrically coupled to the antenna 32 via an RF signal-directing element 52, such as a circulator for example. The RF signal-directing element 52 serves to direct the downlink electrical RF communications signals 50D and the uplink electrical RF communications signals 50U, as discussed below. In accordance with an exemplary embodiment, the antenna 32 can include one or more patch antennas, such as disclosed in U.S. patent application Ser. No. 11/504,999, filed Aug. 16, 2006 entitled “Radio-over-Fiber Transponder With A Dual-Band Patch Antenna System,” and U.S. patent application Ser. No. 11/451,553, filed Jun. 12, 2006 entitled “Centralized Optical Fiber-based Wireless Picocellular Systems and Methods,” both of which are incorporated herein by reference in their entireties.
With continuing reference to FIG. 2, the optical fiber-based distributed antenna system 10 also includes a power supply 54 that generates an electrical power signal 56. The power supply 54 is electrically coupled to the HEU 12 for powering the power-consuming elements therein. In an exemplary embodiment, an electrical power line 58 runs through the HEU 12 and over to the RAU 14 to power the O/E converter 30 and the E/O converter 34 in the converter pair 48, the optional RF signal-directing element 52 (unless the RF signal-directing element 52 is a passive device such as a circulator for example), and any other power-consuming elements provided. In an exemplary embodiment, the electrical power line 58 includes two wires 60 and 62 that carry a single voltage and that are electrically coupled to a DC power converter 64 at the RAU 14. The DC power converter 64 is electrically coupled to the O/E converter 30 and the E/O converter 34 in the converter pair 48, and changes the voltage or levels of the electrical power signal 56 to the power level(s) required by the power-consuming components in the RAU 14. In an exemplary embodiment, the DC power converter 64 is either a DC/DC power converter or an AC/DC power converter, depending on the type of electrical power signal 56 carried by the electrical power line 58. In another example embodiment, the electrical power line 58 (dashed line) runs directly from the power supply 54 to the RAU 14 rather than from or through the HEU 12. In another example embodiment, the electrical power line 58 includes more than two wires and carries multiple voltages.
To provide further exemplary illustration of how an optical fiber-based distributed antenna system can be deployed indoors, FIG. 3 is provided. FIG. 3 is a partially schematic cut-away diagram of a building infrastructure 70 employing an optical fiber-based distributed antenna system. The system may be the optical fiber-based distributed antenna system 10 of FIGS. 1 and 2. The building infrastructure 70 generally represents any type of building in which the optical fiber-based distributed antenna system 10 can be deployed. As previously discussed with regard to FIGS. 1 and 2, the optical fiber-based distributed antenna system 10 incorporates the HEU 12 to provide various types of communication services to coverage areas within the building infrastructure 70, as an example. For example, as discussed in more detail below, the optical fiber-based distributed antenna system 10 in this embodiment is configured to receive wireless RF communications signals and convert the RF communications signals into RoF signals to be communicated over the optical fiber 16 to multiple RAUs 14. The optical fiber-based distributed antenna system 10 in this embodiment can be, for example, an indoor distributed antenna system (IDAS) to provide wireless service inside the building infrastructure 70. These wireless signals can include, but are not limited to, cellular service, wireless services such as RFID tracking, Wireless Fidelity (WiFi), local area network (LAN), WLAN, and combinations thereof, as examples.
With continuing reference to FIG. 3, the building infrastructure 70 in this embodiment includes a first (ground) floor 72, a second floor 74, and a third floor 76. The floors 72, 74, 76 are serviced by the HEU 12 through a main distribution frame 78 to provide antenna coverage areas 80 in the building infrastructure 70. Only the ceilings of the floors 72, 74, 76 are shown in FIG. 3 for simplicity of illustration. In the example embodiment, a main cable 82 has a number of different sections that facilitate the placement of a large number of RAUs 14 in the building infrastructure 70. Each RAU 14 in turn services its own coverage area in the antenna coverage areas 80. The main cable 82 can include, for example, a riser cable 84 that carries all of the downlink and uplink optical fibers 16D, 16U to and from the HEU 12. The riser cable 84 may be routed through an interconnect unit (ICU) 85. The ICU 85 may be provided as part of or separate from the power supply 54 in FIG. 2. The ICU 85 may also be configured to provide power to the RAUs 14 via the electrical power line 58, as illustrated in FIG. 2 and discussed above, provided inside an array cable 87, or tail cable or home-run tether cable as other examples, and distributed with the downlink and uplink optical fibers 16D, 16U to the RAUs 14. The main cable 82 can include one or more multi-cable (MC) connectors adapted to connect select downlink and uplink optical fibers 16D, 16U, along with an electrical power line, to a number of optical fiber cables 86.
The main cable 82 enables the multiple optical fiber cables 86 to be distributed throughout the building infrastructure 70 (e.g., fixed to the ceilings or other support surfaces of each floor 72, 74, 76) to provide the antenna coverage areas 80 for the first, second and third floors 72, 74 and 76. In an example embodiment, the HEU 12 is located within the building infrastructure 70 (e.g., in a closet or control room), while in another example embodiment, the HEU 12 may be located outside of the building infrastructure 70 at a remote location. A base transceiver station (BTS) 88, which may be provided by a second party such as a cellular service provider, is connected to the HEU 12, and can be co-located or located remotely from the HEU 12. A BTS is any station or source that provides an input signal to the HEU 12 and can receive a return signal from the HEU 12. In a typical cellular system, for example, a plurality of BTSs are deployed at a plurality of remote locations to provide wireless telephone coverage. Each BTS serves a corresponding cell and when a mobile station enters the cell, the BTS communicates with the mobile station. Each BTS can include at least one radio transceiver for enabling communication with one or more subscriber units operating within the associated cell. Alternatively, radio input could be provided by a repeater or picocell as other examples.
The optical fiber-based distributed antenna system 10 in FIGS. 1-3 and described above provides point-to-point communications between the HEU 12 and the RAU 14. Each RAU 14 communicates with the HEU 12 over a distinct downlink and uplink optical fiber pair to provide the point-to-point communications. Whenever an RAU 14 is installed in the optical fiber-based distributed antenna system 10, the RAU 14 is connected to a distinct downlink and uplink optical fiber pair connected to the HEU 12. The downlink and uplink optical fibers may be provided in the optical fiber 16. Multiple downlink and uplink optical fiber pairs can be provided in a fiber optic cable to service multiple RAUs 14 from a common fiber optic cable. For example, with reference to FIG. 3, RAUs 14 installed on a given floor 72, 74, or 76 may be serviced from the same optical fiber 16. In this regard, the optical fiber 16 may have multiple nodes where distinct downlink and uplink optical fiber pairs can be connected to a given RAU 14.
It may be desirable to provide an optical fiber-based distributed antenna system that can support a wide variety of radio sources. For example, it may be desired to provide an optical fiber-based distributed antenna system that can support various radio types and sources, including but not limited to Long Term Evolution (LTE), US Cellular (CELL), Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Advanced Wireless Services (AWS), iDEN (e.g., 800 MegaHertz (MHz), 900 MHz, and 1.5 GHz), etc. These radios sources can range from 400 MHz to 2700 MHz as an example. To support a radio source, the HEU must contain lasers that are capable of modulating the radio signal into optical RF communications signals at the frequency of the radio signal for transmission over optical fiber. Likewise, lasers must be provided to convert the optical RF communications signals back into electrical RF communications signals at the frequencies of the radio band supported. It is costly to provide different conversion lasers for all possible radio sources that may be desired to be supported by an optical fiber-based distributed antenna system.
In this regard, embodiments disclosed herein include providing sectorization in distributed antenna systems, and related components and methods. As one non-limiting example, the distributed antenna systems may be optical fiber-based distributed antenna systems. The antenna units in the distributed antenna systems can be sectorized. In this regard, one or more radio bands distributed by the distributed antenna systems can be allocated to one or more sectors. The antenna units in the distributed antenna systems are also allocated to one or more sectors. In this manner, only radio frequency (RF) communications signals in the radio band(s) allocated to given sector(s) are distributed the antenna unit allocated to the same sector(s). The bandwidth capacity of the antenna unit is split among the radio band(s) allocated to sector(s) allocated to the antenna unit. The sectorization of the radio band(s) and the antenna units can be configured and/or altered based on capacity needs for given radio bands in antenna coverage areas provide by the antenna units.
FIG. 4 is a schematic diagram to illustrate an example of providing sectorization in a distributed antenna system. In this regard as illustrated in FIG. 4, a distributed antenna system 90 is provided. The distributed antenna system 90 can be, without limitation, an optical fiber-based distributed antenna system. The distributed antenna system 90 can include the exemplary distributed antenna systems discussed above in FIGS. 1-3, or any of the other exemplary distributed antenna systems disclosed herein. The distributed antenna system includes an HEU 92 that is configured to receive and distribute RF communication signals in a plurality of radio bands or frequencies R1-RN. The HEU 92 is configured to distribute the radio bands R1-RN to a plurality of RAUs 94 communcatively coupled to the HEU 94. For example, the RAUs 94 may be distributed in multiple floors 96A-96D in a building 98 or other facility. The HEU 92 is configured to sectorize the RAUs 94 into different sectors. One or more of the radio bands R1-RN can be allocated to each sector.
In this example, the RAUs 94 are allocated to one of three (3) sectors. For example, RAUs 94(1) allocated to a first sector are shown as circle symbols in FIG. 4. RAUs 94(2) allocated to a second sector are shown as triangle symbols in FIG. 4. RAUs 94(3) allocated to a third sector are shown as square symbols in FIG. 4. The RAUs 94 are allocated to one or more sectors as a method of controlling how many radio bands R1-RN are supported by the RAUs 94 and in which the bandwidth of the RAUs 94 are split. As capacity and performance requirements or needs change for the distributed antenna system 90, the sector allocated to particular RAUs 94 can be changed and/or the radio bands R1-RN allocated to a given sector can be changed. The sector allocated to a given RAU 94 can also be changed or reconfigured flexibly and seamlessly to change how the bandwidth of the RAUs 94 is split among allocated radio bands R1-RN. Deployment of additional RAUs 94 to change the amount of bandwidth dedicated to particular radio bands R1-RN is not required.
FIG. 5 is a schematic diagram of another exemplary distributed antenna system 100 that can support sectorization. In this embodiment, the distributed antenna system 100 is an optical fiber-based distributed antenna system comprised of three main components. One or more radio interfaces provided in the form of radio interface modules (RIMs) 102(1)-102(M) in this embodiment are provided in head end equipment 104 to receive and process downlink electrical RF communications signals 106(1)-106(R) prior to optical conversion into downlink optical RF communications signals. The processing of the downlink electrical RF communications signals 106(1)-106(R) can include any of the procession previously described above in the HEU 12 in FIG. 2. The notations “1-R” and “1-M” indicate that any number of the referenced component, 1-R and 1-M, respectively, may be provided. As will be described in more detail below, the head end equipment 104 in this embodiment is configured to accept a plurality of RIMs 102(1)-102(M) as modular components that can be easily installed and removed or replaced in the HEU 104. In one embodiment, the head end equipment 104 is configured to support up to four (4) RIMs 102(1)-102(M) as an example.
Each RIM 102(1)-102(M) can be designed to support a particular type of radio source or range of radio sources (i.e., frequencies) to provide flexibility in configuring the head end equipment 104 and optical fiber-based distributed antenna system 100 to support the desired radio sources. For example, one RIM 102 may be configured to support the Personal Communication Services (PCS) radio band. Another RIM 102 may be configured to support the Long Term Evolution (LTE) 700 radio band. In this example, by inclusion of these RIMs 102, the head end equipment 104 would be configured to support and distribute RF communications signals on both PCS and LTE 700 radio bands. RIMs 102 may be provided in the head end equipment 104 that support any other radio bands desired, including but not limited to PCS, LTE, CELL, GSM, CDMA, CDMA2000, TDMA, AWS, iDEN (e.g., 800 MHz, 900 MHz, and 1.5 GHz), Enhanced Data GSM Environment, (EDGE), Evolution-Data Optimized (EV-DO), 1xRTT (i.e., CDMA2000 1X (IS-2000)), High Speed Packet Access (HSPA), 3GGP1, 3GGP2, and Cellular Digital Packet Data (CDPD). More specific examples include, but are not limited to, radio bands between 400-2700 MHz including but not limited to 700 MHz (LTE), 698-716 MHz, 728-757 MHz, 776-787 MHz, 806-824 MHz, 824-849 MHz (US Cellular), 851-869 MHz, 869-894 MHz (US Cellular), 880-915 MHz (EU R), 925-960 MHz (TTE), 1930-1990 MHz (US PCS), 2110-2155 MHz (US AWS), 925-960 MHz (GSM 900), 1710-1755 MHz, 1850-1915 MHz, 1805-1880 MHz (GSM 1800), 1920-1995 MHz, and 2110-2170 MHz (GSM 2100).
The downlink electrical RF communications signals 106(1)-106(R) are provided to a plurality of optical interfaces provided in the form of optical interface modules (OIMs) 108(1)-108(N) in this embodiment to convert the downlink electrical RF communications signals 106(1)-106(N) into downlink optical signals 110(1)-110(R). The notation “1-N” indicates that any number of the referenced component 1-N may be provided. One downlink optical fiber 113D and one uplink optical fiber 113U could be provided to support multiple channels each using WDM, as discussed in U.S. patent application Ser. No. 12/892,424 previously referenced above. Other options for WDM and FDM are also disclosed in U.S. patent application Ser. No. 12/892,424, any of which can be employed in any of the embodiments disclosed herein.
In this embodiment, the OIMs 108(1)-108(N) are provided in a common housing provided for the head end equipment 104 with the RIMs 102(1)-102(M). Alternatively, the OIMs 108(1)-108(N) could be located separately from the RIMs 102(1)-102(M). The OIMs 108 may be configured to provide one or more optical interface components (OICs) that contain O/E and E/O converters, as will be described in more detail below. The OIMs 108 support the radio bands that can be provided by the RIMs 102, including the examples previously described above. Thus, in this embodiment, the OIMs 108 may support a radio band range from 400 MHz to 2700 MHz, as an example, so providing different types or models of OIMs 108 for narrower radio bands to support possibilities for different radio band supported RIMs 102 provided in the head end equipment 104 is not required. Further, as an example, the OIMs 108s may be optimized for sub-bands within the 400 MHz to 2700 MHz frequency range, such as 400-700 MHz, 700 MHz-1 GHz, 1 GHz-1.6 GHz, and 1.6 GHz-2.7 GHz, as examples.
The OIMs 108(1)-108(N) each include E/O converters to convert the downlink electrical RF communications signals 106(1)-106(R) to downlink optical signals 110(1)-110(R). The downlink optical signals 110(1)-110(R) are communicated over downlink optical fiber(s) 113D to a plurality of RAUs 112(1)-112(P). The notation “1-P” indicates that any number of the referenced component 1-P may be provided. O-E converters provided in the RAUs 112(1)-112(P) convert the downlink optical signals 110(1)-110(R) back into downlink electrical RF communications signals 104(1)-104(R), which are provided over links 114(1)-114(P) coupled to antennas 116(1)-116(P) in the RAUs 112(1)-112(P) to client devices in the reception range of the antennas 116(1)-116(P).
E/O converters are also provided in the RAUs 112(1)-112(P) to convert uplink electrical RF communications signals received from client devices through the antennas 116(1)-116(P) into uplink optical signals 118(1)-118(R) to be communicated over uplink optical fibers 113U to the OIMs 108(1)-108(N). The OIMs 108(1)-108(N) include O/E converters that convert the uplink optical signals 118(1)-118(R) into uplink electrical RF communications signals 120(1)-120(R) that are processed by the RIMs 102(1)-102(M) and provided as uplink electrical RF communications signals 122(1)-122(R).
FIG. 6 is a schematic diagram illustrating more detail regarding the internal components of the head end equipment 104 in FIG. 5 supporting sectorization of RAUs 112 to particular radio bands. Each RIM 102(1)-102(M) includes one or more filters 124 that are configured to filter out the undesired radio bands for the RIM 102 from the received downlink electrical RF communications signals 106(1)-106(R) and uplink electrical RF communications signals 122(1)-122(R). Although multiple downlink electrical RF communications signals 106(1)-106(R) and uplink electrical RF communications signals 122(1)-122(R) are shown, it is understood that only a subset of these signals may be distributed by each RIM 102 according to the filters 124 and radio band of the received uplink electrical RF communications signals 120(1)-120(R) from the OIMs 108. A downlink attenuator 126 and uplink attenuator 128 are provided to control the power level of the downlink electrical RF communications signals 106(1)-106(R) and uplink electrical RF communications signals 122(1)-122(R), respectively. A power detector 130 may be provided to detect the power levels of the downlink electrical RF communications signals 106(1)-106(R) and uplink electrical RF communications signals 122(1)-122(R) for setting the power levels and/or calibrating the downlink and uplink attenuators 126, 128 to provide the desired power levels of these signals. Examples of setting power levels and/or calibrating downlinks and uplinks in head end equipment for a distributed antenna system are provided U.S. Provisional Patent Application Ser. Nos. 61/230,463 and 61/230,472, both of which are incorporated herein by reference in their entireties.
Each of the RIMs 102(1)-102(M) includes a 1:Q downlink splitter 132 to split the received downlink electrical RF communications signals 106(1)-106(R) into a plurality of the downlink electrical RF communications signals 106(1)-106(R) in distinct downlink paths 134(1)-134(Q) to allow sectorization. “Q” represents the number of possible sectors that can be provided by the head end equipment 104. Splitting the downlink electrical RF communications signals 106(1)-106(R) into a plurality of the downlink paths 134(1)-134(Q) allows the received downlink electrical RF communications signals 106(1)-106(R) to be allocated to different sectors. Each of the downlink paths 134(1)-134(Q) includes an isolation block 136(1)-136(Q) coupled to a downlink sector switch 138(1)-138(Q). Each downlink sector switch 138(1)-138(Q) represents a sector 1-Q in the head end equipment 104. The downlink sector switches 138(1)-138(Q) control whether a split downlink electrical RF communications signal 106(1)-106(R) is provided to a given sector 1-Q. Since each downlink sector switch 138(1)-138(Q) represents a given sector 1-Q, the radio band or bands supported by a given RIM 102 can be allocated to a given sector or sectors based on activation of the downlink sector switches 138(1)-138(Q).
The outputs of the downlink sector switches 138(1)-138(Q) are directed to a RIM distribution matrix 140. The RIM distribution matrix 140 is comprised of RIM interfaces 140(1)-140(Q) that interface each of the downlink paths 134(1)-134(Q) (i.e. sectors) in each of the RIMs 102(1)-102(M) to each of the OIMs 108(1)-108(N). In this manner, the downlink sector switches 138(1)-138(Q) activated in the RIMs 102(1)-102(M) define the radio bands provided for each sector 1-Q. For example, if downlink sector switches 138(1) and 138(2) are activated for RIM 102(1), the radio band(s) filtered by the filters 124 for the RIM 102(1) will be provided on sectors 1 and 2. Thus, any RAUs 112 allocated to sectors 1 and 2 will receive RF communications signals for the radio band(s) filtered by the filters 124 for the RIM 102(1) and will be provided on sectors 1 and 2. If the downlink sector switches 138(1) and 138(2) are activated, for example, in any other of the RIMs 102(2)-102(M), the radio band(s) filtered by those RIMs 102(2)-102(M) will also be provided to RAUs 112 allocated to sectors 1 and 2. In this manner, the radio bands provided in the available sectors 1-Q can be controlled by controlling the downlink sector switches 138(1)-138(Q) in the RIMs 102(1)-102(M).
The RIM distribution matrix 140 and the RIM interfaces 140(1)-140(Q) provided therein for each sector 1-Q are coupled to a complementary OIM distribution matrix 142 in an optical interface unit (OIU) 143. The OIM distribution matrix 142 is comprised of a plurality of OIM interface cards 142(1)-142(Q) for each sector. The OIM interface cards 142(1)-142(Q) interface each of the sectors 1-Q to each of the OIMs 108(1)-108(N). Thus, the downlink electrical RF communications signals 106(1)-106(R) allocated to the sectors 1-Q in the RIMs 102(1)-102(M) are provided to the OIMs 108(1)-108(N) to be distributed to the RAUs 112 coupled to the OIMs 108(1)-108(N). Downlink sector switches 144(1)-144(Q) are provided in each OIM 108(1)-108(N) to control which sectors among sectors 1-Q a particular OIM 108(1)-108(N) will support. Activation of the downlink sector switches 144(1)-144(Q) controls whether the OIM 108 supports a given sector 1-Q. A sector(s) selected as being supported by a particular OIM 108 in this embodiment means, in turn, that the RAUs 112 supported by the OIM 108 are allocated to the selected sector(s). For example, if three (3) RAUs 112 are supported by a particular OIM 108, each of these three (3) RAUs 112 will be allocated to the same sectors according to the settings of the downlink sector switches 144(1)-144(Q) in the OIM 108.
The outputs of the downlink sector switches 144(1)-144(Q) in each OIM 108(1)-108(N) are coupled to isolations blocks 146(1)-146(Q), which are coupled to a Q:1 combiner 148. The combiner 148 combines all of the downlink electrical RF communications signals 106(1)-106(R) for the sectors 1-Q selected for an OIM 108 to provide optically converted downlink electrical RF communications signals 106(1)-106(R) for the selected sectors 1-Q as downlink optical RF communications signals 110(1)-110(R) to the RAUs 112 coupled to the OIM 108. A downlink attenuator 150 is provided in each OIM 108(1)-108(N) to allow the power level of the downlink optical RF communications signals 110(1)-110(R) to be controlled and for calibration purposes. A power detector 152 is included in each OIM 108(1)-108(N) to detect the power levels of the downlink optical RF communications signals 110(1)-110(R) to control the setting of the downlink attenuator 150.
Sectorization can also be provided in the uplink paths of the head end equipment 104 to direct uplink optical RF communication signals 118 from the RAUs 112 to the appropriate RIMs 102(1)-102(M) based on the sectors allocated to the RAUs 112 discussed above. In this regard, with continuing reference to FIG. 6, each OIM 108(1)-108(N) includes an uplink attenuator 154 to control the power level of the uplink optical RF communication signals 118(1)-118(R) received from the RAUs 112 supported by the OIM 108(1)-108(N). A 1:Q optical splitter 156 is provided to split the uplink optical RF communication signals 118(1)-118(R) into separate uplink paths 158(1)-158(Q) for each sector 1-Q. In this manner, the uplink paths 158(1)-158(Q), after being isolated by isolation blocks 160(1)-160(Q), can be controlled by uplink sector switches 162(1)-162(Q) provided for each sector 1-Q. Uplink sector switches 162(1)-162(Q) control providing each of the split plurality of uplink optical RF communications signals 118(1)-118(R) to the same sectors 1-Q selected for the OIM 108 according to the activation of the downlink sector switches 144(1)-144(Q). In this manner, the uplink electrical RF communications signals 120(1)-120(R) will be provided to the appropriate RIMs 102(1)-102(M) through the distribution matrices 140, 142.
The RIMs 102(1)-102(M) each include uplink sector switches 164(1)-164(Q) for each sector 1-Q to allow the uplink electrical RF communications signals 120(1)-120(R) from the RAUs 112 allocated to sectors to be passed through the RIMs 102(1)-102(M) allocated to the corresponding sectors. The settings of the uplink sector switches 164(1)-164(Q) for a particular RIM 102 will be the same as the downlink sector switches 138(1)-138(Q) for the RIM 102. The uplink electrical RF communications signals 120(1)-120(R) that are allowed to pass via selection of the uplink sector switches 164(1)-164(Q) are isolated via isolation blocks 166(1)-166(Q) and are passed to a Q:1 combiner 168. The Q:1 combiner 168 combines the uplink electrical RF communications signals 120(1)-120(R) from the RAUs 112 allocated to the same sectors as selected for the RIM 102 according to the uplink sector switches 164(1)-164(Q) to be provided as uplink electrical RF communications signals 122(1)-122(R) from the RIMs 102(1)-102(M).
Sectors can be configured for the RIMs 102(1)-102(M) and OIMs 108(1)-108(N) in any number of manners. For instance, the sector switches 138(1)-138(Q), 144(1)-144(Q), 162(1)-162(Q), 164(1)-164(Q) can be provided by manually actuated switches provided in the head end equipment 104. Alternatively, the sector switches 138(1)-138(Q), 144(1)-144(Q), 162(1)-162(Q), 164(1)-164(Q) can be programmed or changed via control other than manual control. For example, the RIMs 102(1)-102(M) may each include a controller 170, such as a microcontroller or microprocessor for example as illustrated in FIG. 6, that is configured to control the RIM sector switches 138(1)-138(Q), 164(1)-164(Q). Similarly, the OIMs 108(1)-108(N) may each include a controller 172, such as a microcontroller or microprocessor 170 for example, that is configured to control the OIM sector switches 144(1)-144(Q), 162(1)-162(Q). The controllers 170, 172 may be communicatively coupled to an interface, such as a user interface (UI), including a graphical user interface (GUI), that allows a user to configure the settings of the sector switches 138(1)-138(Q), 144(1)-144(Q), 162(1)-162(Q), 164(1)-164(Q) to provide the desired sectorization of the RAUs 112. Examples of providing access to the head end equipment 104 to control settings of components in the head end equipment 104 are provided in U.S. Provisional Patent Application Ser. No. 61/230,472 incorporated herein by reference in its entirety.
With continuing reference to FIG. 6, the sectorization settings may be stored in memory 174, 176 associated with each of the RIMs 102(1)-102(M) and OIMs 108(1)-108(N), respectively. The controllers 170, 172 may be configured to alter and/or update the sectorizations for the RIMs 102(1)-102(M) and OIMs 108(1)-108(N) by setting sectorization settings in the memory 174, 176. The controllers 170, 172 can then consul the memory 174, 176 to apply configured or programmed settings to the sector switches 138(1)-138(Q), 144(1)-144(Q), 162(1)-162(Q), 164(1)-164(Q) to provide the desired sectorization in the distributed antenna system 100. In this regard, FIG. 7 illustrates an exemplary RIM sectorization table 180 that can be provided in the memory 174 in the RIMs 102(1)-102(M) to store default and/or configured sectorization settings for the sector switches 138(1)-138(Q), 164(1)-164(Q) in the RIMs 102(1)-102(M). A similar sectorization table could be provided in the memory 176 of the OIMs 108(1)-108(N) to store default and/or configured sectorization settings for the sector switches 144(1)-144(Q), 162(1)-162(Q) in the RIMs 102(1)-102(M).
With continuing reference to FIG. 7, the RIM sectorization table 180 in this example is a two-dimensional table to allow for sectorization settings to be provided for each RIM 102(1)-102(M) configured in the head end equipment 104. The radio band filtered and allowed to pass through each RIM 102(1)-102(M) is provided in a radio band column 182 in the RIM sectorization table 180. The pass through radio band for the RIMs 102 may be a static setting, or if the filters 124 in the RIMs 102(1)-102(M) are configurable, the pass through radio band stored in the radio band column 182 may be configurable.
For each RIM 102(1)-102(M) and radio band 182 configuration, sectorization settings 184 are provided in the RIM sectorization table 180. In this example, if the pass through radio band configured for a given RIM 102(1)-102(M) is configured to be provided for a given sector or sectors, a “Pband” setting is provided in the sectors row 186 for the RIM 102 under the sectors to be activated, as illustrated in FIG. 7. A gain setting may also be provided, as illustrated in the RIM sectorization table 180. For example, RIM 102(M) is assigned to Sector 1 186(1) with a gain adjustment of −FdB, wherein F=10 Log [n] dB, where n is the active number of services provided on the same radio band. For example if three (3) services are deployed in the same radio band per sector, the gain adjustment could be Pband −5 dB per service.
The appropriate sector switches 138(1)-138(Q), 164(1)-164(Q) are activated according to the sector settings for the RIMs 102(1)-102(M) in the sectors row 186. For example, for the RIM 102(3) in the RIM sectorization table 180, sector switches 138(1), 164(1) will be activated with the other sector switches 138(2)-138(Q), 164(2)-164(Q) deactivated for the RIM 102(3) to pass through radio band “Band 1” to be included Sector 1 and provided to RAUs 112 allocated to Sector 1 in the OIMs 108(1)-108(N). Further, an attenuation level may be provided for a sector setting that is applied to the downlink attenuator 126 in the RIMs 102(1)-102(M).
Other configurations of allocating sectors to OIMs may be provided. For example, it may be desired to allocate additional RAUs 112 to a sector(s) that can be supported in the head end equipment 104 in FIGS. 5 and 6 as an example. For example, if the optical interface component (OIU) 143 supporting the OIMs 108(1)-108(N) in FIG. 6 is configured to support thirty-six (36) RAUs 112(1)-112(P), and it is desired to allocate additional RAUs to a sector or sectors in the head end equipment 104, such would not be possible with the example head end equipment 104 in FIG. 6. In this regard, FIG. 8 is a schematic diagram of the exemplary head end equipment 104 in FIGS. 5 and 6, but configured with one or more expansion ports 190 to allow additional OIUs 143(2)-143(T) to be allocated to a sector or sectors provided by the head end equipment 104. The notation “T” indicates that any number of additional OIUs may be provided.
As illustrated in FIG. 8, expansion ports 190(1)-190(Q) are provided in the head end equipment 104 to receive RF communications signals assigned to a sector(s) in the RIMs 102(1)-102(M) provided in the head end equipment 104. Additional OIUs 143(2)-143(T) each supporting the OIMs 108(1)-108(N) that each support the RAUs 112(1)-112(P) can be coupled to the expansion ports 190(1)-190(Q). In this manner, the additional RAUs 112(1)-112(P) supported by the OIMs 108(1)-108(M) in the OIUs 143(2)-143(T) can be allocated to sectors provided by the head end equipment 104. For example, as illustrated in FIG. 8, an OIM distribution matrix 142(2) provided in the OIU 143(2) is coupled to the expansion port 190(1) for Sector 1 so that OIMs 108(1)-108(N) in the OIC 143(2) can be configured to receive RF communications signals from the RIMs 102(1)-102(M) in the head end equipment 104 configured for Sector 1. The sector switches (not shown) in the OIMs 108(1)-108(N) in the OIU 143(2) can be set to allocate RAUs 112(1)-112(P) supported by the OIU 143(2) to Sector 1, if desired. Note that FIG. 8 only illustrates the expansion ports 190 being provided in the downlink of the head end equipment 104, but expansion ports can also be provided in the uplink of the head end equipment 104 as well.
The RAUs 112(1)-112(P) supported by the OIU 143(2) in FIG. 8 can only be allocated to one sector provided in the head end equipment 104, which is Sector 1 in this example, because the OIU 143(2) is not coupled to the other expansion ports 190(2)-190(Q) in the head end equipment 104. However, in FIG. 9, the OIU 143(2) is configured to be coupled to each of the sectors provided by the head end equipment 104. In this manner, the RAUs 112(1)-112(P) supported by the OIMs 108(1)-108(N) in the OIU 143(2) can be allocated to any of the sectors provided by the head end equipment 104. Thus, the OIU 143(2) is configured to provide multiple sectors to the RAUs 112(1)-112(P) supported by the OIMs 108(1)-108(N) in the OIU 143(2). Note that FIG. 9 only illustrates the expansion ports 190 being provided in the downlink of the head end equipment 104, but expansion ports can also be provided in the uplink of the head end equipment 104 as well.
The head end equipment 104 can also be configured to share components with multiple carriers. For example, a distributed antenna system may include multiple carriers. Further, an installation of a distributed antenna system with a first carrier may be later configured to support other carriers. In this regard, FIG. 10 illustrates the head end equipment 104 where two (2) carriers (CARRIER 1 and CARRIER 2) provide their own respective downlink electrical RF communications signals 106(1)-106(R) to radio interfaces 200(1), 200(2), respectively, having their own dedicated RIMs 102(1)-102(M). An external radio distribution matrix 204 is provided that allows each of the RIMs 102(1)-102(M) provided in the radio interfaces 200(1), 200(2) to share the same OIUs 143(1)-143(T) and supported RAUs 112(1)-112(P). In this manner, additional OIUs 143 and associated cabling are not required for each carrier to route RF communications signals to the shared RAUs 112(1)-112(P). RAUs 112(1)-112(P) can be allocated to sectors that include RF communications signals from both carriers.
The head end equipment 104 can also be configured to provide additional sectors as illustrated in FIG. 11. For example, if the head end equipment 104 in the previous figures supports three (3) sectors, additional radio interfaces 200(1)-200(S) can be provided, as illustrated in FIG. 11, to provide additional sectors in a modular fashion. The notation “S” indicates that any number of radio interfaces may be provided. The external radio distribution matrix 204 routes the expanded sectors to the OIUs 143(1)-143(T) such that the RAUs 112(1)-112(P) supported by any of the OIUs 143(1)-143(T) can be allocated to any of the expanded number of sectors provided by the radio interfaces 200(1)-200(S).
FIG. 12 is a schematic diagram of an exemplary head end equipment 104 provided in the distributed antenna system 100 supporting sectorization and multiple-input, multiple-output (MIMO) processing in a distributed antenna system. MIMO can provide increased bit rates or beam forming for signal-to-noise ratios (SNRs) through improved spectrum efficiency and/or wireless distance improvement. In this embodiment, MIMO is achieved by utilizing multiple spatial layers (e.g., up to four (4) layers by 3GPP standards) to a given client device.
FIG. 12 illustrates the head end equipment 104 illustrated in FIG. 5 and previously discussed configured to support 2×2 MIMO with two (2) sectors. Common elements are illustrated in FIG. 12 with common element numbers and will not be redescribed. A 2×2 MIMO scheme can be provided for the distributed antenna system 100 when two (2) RAUs 112(1), 112(2) are co-located to create two (2) spatial streams using the same frequency radio band as illustrated in FIG. 12, but any other MIMO configuration desired is also possible.
With continuing reference to FIG. 12, the first and second sectors in this example are associated with first and second radio streams 210(1), 210(2), respectively. The first and second radio streams 210(1), 210(2) each contain four (4) radio bands in this example. The RAUs 112(1), 112(2) are assigned to sectors such that all four (4) of the radio bands in the radio streams 210(1), 210(2) are delivered to two (2) RAUs 112(1), 112(2) deployed at the same location in this example. In this example, RAU 112(1) is assigned to a first sector that includes the four (4) radio bands in the first radio stream 210(1). RAU 112(2) is also assigned to the same sector as assigned to the RAU 112(1). Thus, radio communications to the RAUs can support MIMO communications across the four (4) radio bands provided in the radio streams 210(1), 210(2). The radio bands supported in MIMO communications by the RAUs 112(1), 112(2) can be changed by reassigning the RAUs 112(1), 112(2) to different sectors or reconfiguring existing sectors to which the RAUs 112(1), 112(2) are assigned.
Those of skill in the art would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithms described in connection with the embodiments disclosed herein may be implemented as electronic hardware, instructions stored in memory or in another computer-readable medium and executed by a processor or other processing device, or combinations of both. The components of the distributed antenna systems described herein may be employed in any circuit, hardware component, integrated circuit (IC), or IC chip, as examples. Memory disclosed herein may be any type and size of memory and may be configured to store any type of information desired. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. How such functionality is implemented depends upon the particular application, design choices, and/or design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A controller may be a processor. A processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The embodiments disclosed herein may be embodied in hardware and in instructions that are stored in hardware, and may reside, for example, in Random Access Memory (RAM), flash memory, Read Only Memory (ROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of computer readable medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a remote station. In the alternative, the processor and the storage medium may reside as discrete components in a remote station, base station, or server.
It is also noted that the operational steps described in any of the exemplary embodiments herein are described to provide examples and discussion. The operations described may be performed in numerous different sequences other than the illustrated sequences. Furthermore, operations described in a single operational step may actually be performed in a number of different steps. Additionally, one or more operational steps discussed in the exemplary embodiments may be combined. It is to be understood that the operational steps illustrated in the flow chart diagrams may be subject to numerous different modifications as will be readily apparent to one of skill in the art. Those of skill in the art would also understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Further, as used herein, it is intended that terms “fiber optic cables” and/or “optical fibers” include all types of single mode and multi-mode light waveguides, including one or more optical fibers that may be upcoated, colored, buffered, ribbonized and/or have other organizing or protective structure in a cable such as one or more tubes, strength members, jackets or the like. The optical fibers disclosed herein can be single mode or multi-mode optical fibers. Likewise, other types of suitable optical fibers include bend-insensitive optical fibers, or any other expedient of a medium for transmitting light signals. An example of a bend-insensitive, or bend resistant, optical fiber is ClearCurve® Multimode fiber commercially available from Corning Incorporated. Suitable fibers of this type are disclosed, for example, in U.S. Patent Application Publication Nos. 2008/0166094 and 2009/0169163, the disclosures of which are incorporated herein by reference in their entireties.
Many modifications and other embodiments of the embodiments set forth herein will come to mind to one skilled in the art to which the embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the description and claims are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. It is intended that the embodiments cover the modifications and variations of the embodiments provided they come within the scope of the appended claims and their equivalents. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

## Claims

1. A method of providing RF communications signals from radio bands distributed among a plurality of sectors in a distributed antenna system, the method comprising:
receiving in a plurality of radio interfaces, a plurality of downlink radio frequency (RF) communications signals;
in each radio interface among the plurality of radio interfaces:
providing a downlink RF communications signal among the plurality of downlink RF communications signals;
splitting the received downlink RF communications signal into a plurality of split downlink RF communications signals;
selectively switching the split plurality of downlink RF communications signals to one or more sectors among a plurality of sectors;

in each optical interface (OI) among a plurality of OIs, wherein each OI supports a subset of remote antenna units (RAUs) among a plurality of remote antenna units (RAUs):
receiving the plurality of split downlink RF communications signals from the plurality of sectors;
converting the plurality of split downlink RF communications signals into a plurality of downlink optical RF communications signals; and
selectively switching the plurality of sectors in the OI to allocate a selected one or more sectors among the plurality of sectors to the subset of RAUs supported by the OI, to provide the downlink optical RF communications signal among the plurality of split downlink optical RF communications signals selectively switched to the one or more sectors, to the subset of RAUs.

2. The method of claim 1, wherein at least one of the OIs supports at least three RAUs, and wherein the at least three RAUs supported by the OIs are allocated to the same sector or sectors.

3. The method of claim 2, further comprising combining the downlink RF communications signal received at an OI.

4. The method of claim 2, further comprising each of the at least three RAUs transmitting RF signals into a respective coverage area.

5. The method of claim 4, further comprising each of the at least three RAUs receiving RF signals from wireless devices in respective coverage areas.

6. The method of claim 4, wherein the distributed antenna system is deployed in at least three floors of a building infrastructure.

7. The method of claim 1, further comprising distributing the split plurality of downlink RF communications signals for the plurality of sectors in a distribution matrix.

8. The method of claim 1, wherein every OI in the distributed antenna system supports at least three RAUs.

9. The method of claim 1, further comprising
in each OI among the plurality of OIs, combining the downlink RF communications signal among the plurality of downlink optical RF communications signals selectively switched to the one or more sectors.

10. The method of claim 1, further comprising:
splitting a received uplink RF communications signal into a split plurality of uplink RF communication signals;
providing each of the split plurality of uplink RF communications signals to one or more sectors; and
controlling for which sectors the received plurality of split uplink RF communications signals are provided to one or more carriers.

11. The method of claim 10, wherein the split plurality of uplink RF communications signals is comprised of a split plurality of uplink optical RF communications signals; and
further comprising converting the split plurality of uplink optical RF communications signals into a plurality of uplink electrical RF communications signals.

12. The method of claim 1, wherein every OI in the distributed antenna system supports a plurality of RAUs.

13. The method of claim 1, wherein:
receiving the plurality of downlink RF communications signals further comprises receiving the plurality of downlink RF communications signals each having different frequency bands; and
splitting the received downlink RF communications signal comprises splitting the received downlink RF communications signal in the frequency band into the plurality of downlink RF communications signals each in the frequency band.

14. The method of claim 1, wherein:
the plurality of OIs are comprised of a plurality of optical interface modules (OIMs);
receiving in the plurality of radio interfaces, the plurality of downlink RF communications signals comprises receiving a plurality of downlink RF communications signals;
splitting the received downlink RF communications signal into the plurality of downlink RF communications signals comprises splitting the received downlink electrical RF communications signal into the plurality of downlink electrical RF communications signals; and
converting the plurality of split downlink RF communications signals comprises converting the plurality of split downlink electrical RF communications signals into the plurality of downlink optical RF communications;
selectively switching the plurality of downlink optical RF communications signals to one or more sectors among a plurality of sectors comprises selectively switching the plurality of downlink optical RF communications signals to the one or more sectors.

15. The method of claim 1, further comprising, in each radio interface among the plurality of radio interfaces, selectively switching a plurality of radio interface downlink switches, each receiving a split downlink RF communications signal among the plurality of split downlink RF communications signals, to selectively switch the split downlink RF communications signal to the one or more sectors.

16. The method of claim 1, further comprising, in each OI among the plurality of OIs, selectively switching a plurality of OI downlink switches, each coupled to a sector among the plurality of sectors, to provide the downlink optical RF communications signal among the plurality of downlink optical RF communications signals selectively switched to the one or more sectors, to the subset of RAUs.

17. The method of claim 1, further comprising assigning at least two RAUs among the plurality of RAUs in a MIMO communication configuration.

18. The method of claim 1, further comprising assigning at least two of the subset of RAUs among the plurality of RAUs assigned to the allocated to the one or more sectors in the MIMO communication configuration.