Abstract:
A single unit with a backhaul interface and radio card able to support both metro cell outdoor (MCO) and metro radio outdoor (MRO) operations. The single unit includes a switch used to switch between these operational modes. The single unit is versatile from the standpoint that MCO or MRO operations may be selected at the time of installation, and this selection may be changed at any time while operating. The single unit configuration provides a low power MRO mode requiring up to 80% less power than the MCO mode, as the switching function of the single unit can power down all unused internal components and allow radio signals received at a backhaul interface to be exchanged directly with a radio card.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Example embodiments relate generally to a single unit small, outdoor low-power cell able to support both metro cell outdoor (MCO) and metro radio outdoor (MRO) operations. 
         [0003]    2. Related Art 
         [0004]    In telecommunications, small, low-power cells are designed to supplement and/or replace larger macro base stations, especially in heavily populated urban areas where space is at a premium. To that end, conventionally there are two broad classes of small cells: metro cell outdoor (MCO), and metro radio outdoor (MRO). 
         [0005]    As shown in  FIG. 1 , a conventional MRO  10  includes a radio card  2  which may include a digital processing radio processor  6  (containing such algorithms as Peak Limiter and Digital Pre-Distortion for radio performance) and dual common public radio interfaces (CPRI)  4  (providing digital communication to the radio with standard messaging and data, where dual connections are provided for redundancy as well as daisy-chaining with other radios). The radio card  2  may also include a radio on card transmitter (TX RoC)  12  for transmitting modulation, and a radio on card receiver (RX RoC)  14  for receiving demodulation. MRO  10  may also include a backhaul module  18  with dual backhaul interfaces  16  connected to fiber lines  22 , where the backhaul interfaces  16  may be CPRI rates  3  through  7  for radio applications, those these interfaces  16  may optionally support gigabit ethernet (GigE) for cell applications (see for instance the configuration shown in  FIG. 2 ). CPRI interfaces  4  of the radio card  2  may be connected to the backhaul interfaces  16  of backhaul module  18  via CPRI lanes  24  carrying CPRI signals that may be included in connector  8  (note that these lanes  24  may optionally be serializer/deserializer (SERDES) GigE for cell applications, as shown in  FIG. 2 ). 
         [0006]    As shown in  FIG. 2 , a conventional MCO  30  for modem and radio processing may include a radio card  2  and backhaul module  18  with similar components as described in  FIG. 1  (and therefore those components are not again described here). However, in contrast to  FIG. 1 , MCO  30  may include a modem  48  connecting backhaul module  18  to radio card  2 . The modem card  48  may include an Ethernet switch  32  and base band controller  28  for long-term evolution (LTE) processing. The Ethernet switch  32  may be used to direct Ethernet packets (packets conforming to IP protocol) internally within modem  48 . Specifically, Ethernet switch  32  may include Ethernet port interfaces  42  (see ports P 0  and P 1 ) which terminate Serial Gigabit Media Independent Interface (SGMII) signals (i.e., IP protocol data) carried to/from Ethernet switch  32  and backhaul interfaces  16  via SGMII SERDES lanes  46 . Ethernet switch  32  may also include Ethernet port interfaces  40  (see ports P 2  and P 3 ) which terminate SGMII signals carried to/from SGMII interfaces  36  of base band controller  28  via SERDES SGMII lanes  38 . The SGMII interfaces  36  may be serial gigabit media independent interfaces used to transport control and data packets to the network. Base band controller  28  may also include internal CPRI core interfaces  34  that send/receive CPRI signals to CPRI interfaces  4  of radio card  2  via SERDES lanes  26 , where base band controller  28  may convert CPRI signals to SGMII signals and vice versa. 
         [0007]    Due to the structural differences between the hardware configuration of the conventional MRO  10  and MCO  30 , both types of equipment must be utilized in the field in order to provide metro radio services and metro cell services to user equipment (UE) of a wireless network. 
       SUMMARY OF INVENTION 
       [0008]    Some example embodiments provide a method and/or apparatus for a single unit small, outdoor low-power base station able to support both metro cell outdoor (MCO) and metro radio outdoor (MRO) operations. In one embodiment, a single unit base station may include a switch that is capable of switching received signals between MCO and MRO operations. The single unit base station is versatile from the standpoint that the base station may be easily switched between MCO and MRO operations at the time of installation, and the base station may be changed between MCO and MRO operations at any time during operation. The single unit base station configuration may also provide a low power MRO mode requiring up to 80% less power than the MCO mode, as the switching function of the single unit may power down all active components such that CPRI signals received at the backhaul interfaces may be sent directly to a radio card. 
         [0009]    In one embodiment, a single unit may include a backhaul interface; a radio card configured to exchange data communication with the backhaul interface; a first controller configured to convert internet protocol (IP) data to radio signals, the first controller being a base band controller; and a first switch configured to route IP data communication between the backhaul interface and the radio card through the first controller, and route radio signal data communication directly between the backhaul interface and the radio card. 
         [0010]    In one embodiment, a method of configuring a single unit having a backhaul interface capable of exchanging data communication with a radio card may include configuring a first controller in the single unit to convert internet protocol (IP) data into radio signals, the first controller being a base band controller; and configuring a first switch in the single unit to route IP data communication between the backhaul interface and the radio card through the base band controller, and route radio signal data communication directly between the backhaul interface and the radio card. 
         [0011]    In one embodiment, a method of using a single unit having a backhaul interface capable of exchanging data communication with a radio card, may include selecting, by a first switch controlled by a first controller, one of a metro cell outdoor (MCO) mode and a metro radio outdoor (MRO) mode, the first switch routing internet protocol (IP) data communication between the backhaul interface and the radio card through a second controller in the MCO mode, the second controller being a base band controller configured to convert IP data into radio signals, the first switch routing radio signal data communication directly between the backhaul interface and the radio card in the MRO mode. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above and other features and advantages of example embodiments will become more apparent by describing in detail, example embodiments with reference to the attached drawings. The accompanying drawings are intended to depict example embodiments and should not be interpreted to limit the intended scope of the claims. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. 
           [0013]      FIG. 1  is a diagram of a conventional metro radio outdoor (MRO) cell; 
           [0014]      FIG. 2  is a diagram of a conventional metro cell outdoor (MCO) cell; 
           [0015]      FIG. 3A  is a diagram of a single unit cell (MxO) operating in a MRO mode, in accordance with an example embodiment; 
           [0016]      FIG. 3B  is a diagram of single unit cells (MxO) in MRO mode connected in parallel, in accordance with an example embodiment; 
           [0017]      FIG. 4  is a diagram of the single unit cell (MxO) of  FIG. 3A , operating in a MCO mode, in accordance with an example embodiment; 
           [0018]      FIG. 5  is a method of configuring a single unit cell with a switching capability between MRO and MCO modes, in accordance with an example embodiment; and 
           [0019]      FIG. 6  is a method of using a single unit cell with a switching capability between MRO and MCO modes, in accordance with an example embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    While example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but on the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the claims. Like numbers refer to like elements throughout the description of the figures. 
         [0021]    Before discussing example embodiments in more detail, it is noted that some example embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations as sequential processes, many of the operations may be performed in parallel, concurrently or simultaneously. In addition, the order of operations may be re-arranged. The processes may be terminated when their operations are completed, but may also have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, subprograms, etc. 
         [0022]    Methods discussed below, some of which are illustrated by the flow charts, may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine or computer readable medium such as a storage medium, such as a non-transitory storage medium. A processor(s) may perform the necessary tasks. 
         [0023]    Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. This invention may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein. 
         [0024]    It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0025]    It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). 
         [0026]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. 
         [0027]    It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. 
         [0028]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0029]    Portions of the example embodiments and corresponding detailed description are presented in terms of software, or algorithms and symbolic representations of operation on data bits within a computer memory. These descriptions and representations are the ones by which those of ordinary skill in the art effectively convey the substance of their work to others of ordinary skill in the art. An algorithm, as the term is used here, and as it is used generally, is conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of optical, electrical, or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. 
         [0030]    In the following description, illustrative embodiments will be described with reference to acts and symbolic representations of operations (e.g., in the form of flowcharts) that may be implemented as program modules or functional processes include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types and may be implemented using existing hardware at existing network elements. Such existing hardware may include one or more Central Processing Units (CPUs), digital signal processors (DSPs), application-specific-integrated-circuits, field programmable gate arrays (FPGAs) computers or the like. 
         [0031]    It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” of “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical, electronic quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
         [0032]    Note also that the software implemented aspects of the example embodiments are typically encoded on some form of program storage medium or implemented over some type of transmission medium. The program storage medium may be any non-transitory storage medium such as magnetic (e.g., a floppy disk or a hard drive) or optical (e.g., a compact disk read only memory, or “CD ROM”), and may be read only or random access. Similarly, the transmission medium may be twisted wire pairs, coaxial cable, optical fiber, or some other suitable transmission medium known to the art. The example embodiments not limited by these aspects of any given implementation. 
         [0033]      FIG. 3A  is a diagram of a single unit cell (MxO)  50  operating in a MRO mode, in accordance with an example embodiment. MxO  50  may support either MCO or MRO operations, though operation in MRO-only is shown in this figure (also see MxO  50  in MCO mode in  FIG. 4 ). Because MxO  50  shares some common elements with MCO  30  (see the description of  FIG. 2 , above), these common elements are not described again, here. 
         [0034]    MxO  50  may include a master controller  54  that controls the internal components of MxO  50 , the function of which is described herein. A physical switch  52  such as a cross-point switch, or any other type of switch offering a switching function capable of redirecting either CPRI or SERDES SGMII signals within modem  48  may also be included in MxO  50 , in order to switch MxO  50  from MRO mode to MCO mode. In MRO mode, controller  54  causes switch  52  to receive CPRI signals  58  (entering from backhaul interface  16 ) and allow the signals  58  to pass directly through switch  52  and to CPRI interface  4  of radio card  2 , allowing signals  58  to be freely exchanged between backhaul  16  and CPRI interface  4 . The MRO-only mode allows for a significant reduction in power usage, as compared to the configuration of  FIG. 4 , as controller  54  may send control signals to Ethernet switch  32  and base band controller  28  in order to cause Ethernet switch  32  and base band controller  28  to power down during this more. This power savings also allows MxO  50  to operate in MRO mode at up to 80% less power than a conventional MCO  30  (as shown in  FIG. 2 ). 
         [0035]    It should also be understood that, as depicted in  FIG. 3A , CPRI signals  58  are only shown between a single backhaul interface  16  (BH 1 ) and a single CPRI interface  4  (CPRI- 1 ) of the radio card  2 . However, it should be understood that the other backhaul interface  16  (BH 2 ) may carry CPRI signals to and from the other CPRI interface  4  (CPRI- 2 ) at the same time. It should further be understood that while no active data communication is shown between switch  52 , Ethernet  32  and base band controller  28 , because there would be no active communication between these components in MRO mode, lanes still do exist that connect these components to each other (see lanes  66 ,  64  and  56  of  FIG. 4 , showing active communication occurring using these lanes in MCO mode). 
         [0036]      FIG. 3B  is a diagram of single unit cells (MxO)  50  in MRO mode connected in parallel, in accordance with an example embodiment. In the MRO mode, MxO  50  may be capable of supporting a ‘daisy chain’ configuration with another MxO  50 , or a plurality of MxO  50  in series. In this configuration, CPRI radio signal  58  for use by multiple radios may be received from a base band unit  86  on backhaul BH 1 . The digital processing portion  6  of the radio  2  may process radio signal  58 , and select a portion of the digital signal to transmit over the air via transmitter  12 . The digitized radio signal  58   a  may then be transmitted from interface CPRI- 2  of radio card  2  through backhaul interface BH 2  over fiber line  22   a  to be received by a backhaul interface BH 1   a  of an MxO  50   a  that is identical to MxO  50  (note that all of the internal components of MxO  50   a  are not shown to simplify the drawing). This signal  58   a  contains only digitized radio signals for the second MxO  50   a  (and, subsequent MxO units, if desired as explained herein). MxO  50   a  may process signal  58   a  in order to broadcast a select portion of signal  58   a  over radio card  2   a.  It should be understood that additional MxO units may also be included in this ‘daisy chain’ in a similar fashion, with Backhaul BH 2   a  being used to transmit a radio signal to these additional units if desired. This type of configuration eliminates a need ofr separate fiber lines  22  to each individual MxO 
         [0037]    In general, use of crosspoint switch  52  within MxO  52 , along with control logic  54  to allow switching between MRO mode and MCO mode (see  FIG. 4 ), allows a variety of potential MxO configurations supporting different deployment scenarios such as MCO, MRO, MRO Daisy Chain, though this list is not exhaustive, but merely illustrative of the variety of deployment scenarios that can be addressed by the single MxO  50  unit. 
         [0038]      FIG. 4  is a diagram of the single unit cell (MxO)  50  of  FIG. 3A , operating in a MCO mode, in accordance with an example embodiment. The switching of MxO  50  from MRO mode ( FIG. 3A ) to MCO mode ( FIG. 4 ) may be accomplished manually (either prior to field installation, or in the field prior to power up and operation of MxO  50 ) through controller  54  sending a control signal to switch  52  in order to redirect incoming SGMII signals  59  (rather than having the signals pass through switch  52  directly to radio card  2 ). While this manual action of causing controller  54  to activate the switching of switch  52  may be accomplished at MxO  50  (requiring a technician to be physically at the site of MxO  50  to accomplish the switching procedure), it should be understood that this manually switching may also be accomplished remotely by sending a control signal  82  from a remote location  80  (where the remote location may be in the general vicinity of MxO  50 , or a considerable distance from MxO  50  such as at central office). 
         [0039]    In MCO mode, controller  54  may cause incoming SGMII signals  59  received at switch  52  to be redirected toward Ethernet switch  32  via CPRI lane  66 . The SGMII signals are then transmitted via SGMII lanes  64  to the SGMII interface  36  of base band controller  28 . Then, base band controller  28  may convert SGMII signals (IP protocol) into CPRI signals (radio signals), and send these radio signals to switch  52  via CPRI lanes  56 . CPRI signals  58  are then transmitted from switch  52  to CPRI interface  4  of radio card  2  via CPRI lanes  62 . 
         [0040]    It should be understood that a path between backhaul interface BH 2  through switch  52 , Ethernet  32 , base band controller  28 , back through switch  52  to interface CPRI- 2  may also be used to conduct communications if desired. 
         [0041]      FIG. 5  is a method of configuring a single unit MxO  50  with a switching capability between MRO and MCO modes (as shown in  FIGS. 3 and 4 ), in accordance with an example embodiment. The method may include a step S 100  of inserting a switch  52  and controller  54  into a MCO  30  to produce a single unit MxO  50 . Step S 110  may include configuring the controller  54  to selectively redirect signals through switch  52  to provide MxO  50  with either MRO or MCO operations (as shown in  FIGS. 3 and 4 ). Step S 120  may include configuring controller  54  to send control signals to power down Ethernet switch  32  and base band controller  28  in an energy saving mode during MRO mode (as shown in  FIG. 3A ). 
         [0042]      FIG. 6  is a method of using a single unit cell MxO  50  with a switching capability between MRO and MCO modes, in accordance with an example embodiment. Step S 200  may include MxO  50  in a power ‘off’ mode. In step S 210 , controller  54  of MxO  50  may be manually activated to cause switch  52  to be switched a MRO mode (see  FIG. 3A ). Controller  54  may also alternatively cause switch  52  to be switched to a MCO mode (see  FIG. 4 ), as shown in step S 240 , and this alternative mode is described in more detail herein. However, assuming MxO  50  is initially switched to MRO, then in step S 220  controller  54  may cause components of MxO  50  to power on, with the exception of Ethernet switch  32  and base band controller  28  which are not utilized during MRO mode. In step S 230 , MxO  50  may then send and receive signals. In step S 270 , it may be decided to continue MRO operations indefinitely (in which case MxO  50  may continue to send and receive signals in step S 230 ), or a decision to switch to MCO mode may be made. 
         [0043]    In the event it is desired to switch from MRO mode to MCO mode, then in step S 275  data communications for MxO  50  cease prior to controller  54  being manually activated to cause switch  52  to be switched to MCO mode (see  FIG. 4 ) in step S 240 . In step S 250 , all MxO  50  components are powered up, including Ethernet switch  32  and base band controller  28 . In step S 260  MxO  50  may send and receive signals. In step S 280 , it may be decided to continue MCO operations indefinitely (in which case MxO  50  may continue to send and receive signals in step S 260 ), or a decision to switch to MRO mode may be made (in which case data communications cease in step S 285 ). Following step S 285 , controller  54  may switch MxO  50  back to MRO mode, as shown in step S 210 . 
         [0044]    Example embodiments having thus been described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the intended spirit and scope of example embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.