Patent Publication Number: US-10790578-B2

Title: Modular small cell architecture

Description:
RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 15/997,721, filed on Jun. 5, 2018, which is a continuation of U.S. patent application Ser. No. 15/216,029, filed on Jul. 21, 2016 (now U.S. Pat. No. 9,997,825), which is a continuation of U.S. patent application Ser. No. 14/316,424 filed Jun. 26, 2014 (now U.S. Pat. No. 9,433,034), which claims the benefit of U.S. Provisional Application No. 61/866,764, filed on Aug. 16, 2013, the disclosures of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     As wireless data service demands have grown, a conventional response has been to increase the number and capacity of conventional cellular Base Stations (Macro-Cells). However, Macro Cell sites are becoming less available, and available spectrum limits how much additional capacity can be derived from a given Macro Cell. Accordingly, small cell radios and antenna combinations have been developed to “fill in” underserved or congested areas that would otherwise be within a macro site. Deployment of small cells, particularly in Urban environments is expected to continue to grow. 
     Currently known small cells integrate an access radio and antenna and a back-haul radio and antenna in a single assembly. Often, heat sink fins are exposed. Such small cell radios may face opposition to installation due to poor aesthetics. Also, they are typically too heavy for a single person to lift, and require lifting machinery (a crane or bucket truck) to install on a pole. Such radios also typically lack a path for sector or carrier growth, have RF “blind spots” caused by a mounting pole, and lack flexibility in back-haul links, or selective provision of additional services. Integrated base station antennas in access radios offer poor RF delivery which can result in reduced capacity handling and higher costs. 
    
    
     
       CONCISE DESCRIPTION OF THE SEVERAL FIGURES 
         FIGS. 1( a ) and 1( b )  show an overview of the Sector Radio Modules of the subject invention. 
         FIGS. 2( a ), 2( b ), 2( c ) and 2( d )  show one embodiment of the module of the subject invention, 
         FIG. 3  shows a radome cover of the subject invention. 
         FIGS. 4-6  shows different aspects of the radio cooling system of the subject invention. 
         FIGS. 7( a ) and 7( b )  shows details of the radome cover assemblies. 
         FIGS. 8( a ), 8( b ), and 8( c )  show details of the radome cover assemblies. 
         FIGS. 9( a ) and 9( b )  show details of the radome cover assemblies. 
         FIGS. 10( a ) and 10( b )  show the Sector Radio Modular of the subject invention with a mounting bracket. 
         FIG. 11  show knockout ports in the brackets. 
         FIG. 12  shows the possible disassembly of a module of the subject invention. 
         FIG. 13  shows a mobile application of the subject invention. 
         FIG. 14  shows the system of the subject invention having more than one carrier. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A modular sectorized small-cell architecture is disclosed herein. The modular architecture includes one or more common modules coupled to one or more sector radio modules. The disclosed architecture results in lightweight modular components that a single service technician can lift and install without lifting machinery. Due to the sectorized designs, there is no RF blind spot. Capacity may be added on an as-needed basis, keeping costs in line with service demands and revenues. Also, back-haul options and additional services may be configured and added in a modular fashion. Finally, the modules have a pleasing aesthetic appearance. 
     In one example, referring to  FIGS. 1 and 2 , three Sector Radio Modules  20  and three common  21  modules may be mounted on a pole  22 . Each common module typically includes a power supply that converts utility line power to a voltage and current suitable for access radio operation. A common module may also include one or more of an optical data fiber demarcation, a WiFi access point, GPS receiver, and surveillance modules. In the illustrated examples, each common module is shaped as a 120° sector  23  of a cylinder. Additional sectorization schemes are possible, such as 90° sectors or 180° sectors. The common module includes perforations to admit and release cooling air, and may include internal baffles to direct cooling air over active components and/or heat sinks. 
     Each common module  21  is typically coupled to a Sector Radio Module  20 . At a minimum, the common module  21  provides power to the Sector Radio Module  20 . The common module  21  may also provide a back-haul link to the Sector Radio Module  20  via the optical fiber demarcation. 
     The Sector Radio Modules  20  each include an access radio and antenna. In the illustrated examples, the Sector Radio Modules  20  are shaped as a 120° sector of a cylinder. The access radio  24  and antenna are configured, for example, to communicate with mobile handsets and other wireless data devices. In the illustrated example, the access radio antenna is configured to have a half power beam width of approximately 65°. This allows each of the three illustrated Sector Radio Modules to serve a 120° sector, providing a three-sector small cell site. None of the three sectors are occluded by the mounting pole. A set of Base Station modules separate to the radio modules may be located at a higher point on the pole to offer improved RF coverage if required. These may be contained in a separate set of modules OR be attached to a stand-off bracket which will include an internal coax jumper cable, fixing point for the antenna and fixing point to the pole. 
     The Sector Radio Modules  20  also may include a low capacity back-haul radio and antenna  25 , and/or a high capacity back-haul and antenna. In one example, a Sector Radio Module  20  may be equipped with a low capacity back-haul antenna  27  and radio to establish a back-haul link with another small cell site, such as another Sector Radio Module. In another example, Sector Radio Module  20  may be equipped with a low capacity back-haul antenna and radio to receive back-haul data from another small cell site, and a high capacity back-haul antenna  26  and radio to establish a back-haul link with a macro cell site or other back-haul link. In other examples, a Sector Radio Module having only a high capacity back-haul antenna and radio, and a Sector Radio Module having no back-haul radio or antenna may be installed. In the last example, back-haul may be established through the optical fiber demarcation in the common module or another Sector Radio Module mounted on the pole. 
     There are several features incorporated into the radome cover assemblies for the Sector Radio Modules. Some or all of these features may also be incorporated in the radomes/covers for the common modules. 
     For example, referring to  FIG. 3 , the radome cover assembly may comprise a lightweight molded plastic cover. The radome cover assembly  30  may further include a molded-in handle  31  for lifting and installation, tuned dielectric properties, and a radio cooling system  32 . 
     Additional details of the radio cooling system are illustrated in  FIGS. 4-6 .  FIG. 4  illustrates perforations  35  allowing the intake of cooling air and exhaust of hot air.  FIG. 5  illustrates the placement of active electronics, such as the access radio  24  and back-haul radios  36 ,  37 , such that cooling air is directed over heatsink fins. The Sector Radio Module may include ducts and baffling to direct cooling air over the heat sinks.  FIGS. 5 and 6  also illustrate that the assembly may be configured to provide mounting locations for access and back-haul radios  36 ,  37 , including radios from different manufacturers. 
       FIGS. 7( a ) and 7( b ) ,  8   a - 8   c  and  9   a - 9   b  illustrate additional details of the tuned dielectric properties of the radome cover assemblies.  FIGS. 7( a ) and 7( b )  illustrate the radome  30  separated from a Sector Radio Module  20 , revealing the access antenna assembly  27 , the high capacity back-haul antenna  26 , and the low capacity back-haul antenna  25 .  FIG. 8 a    illustrates a radome cover assembly  30 .  FIG. 8 b    illustrates a radome cover assembly  30  with an environmental shield  34  removed, allowing tuned dielectric inserts  33  to be viewed. A first dielectric insert may be tuned to the frequency band of an access antenna, a second dielectric insert is tuned to a frequency band of a low capacity back-haul antenna, and a third dielectric insert may be tuned to a frequency band of the high capacity bank-haul antenna.  FIG. 8 c    illustrates how the dielectric inserts are located with respect to the radome cover assembly  30 . Access radios may have frequency bands in the 800 MHz to 2.5 GHz range. Back-haul radios may generate at up to 80 GHz. Additional views are provided in  FIGS. 9 a  and 9 b   . The foregoing allows the dielectric properties of the radome to be matched to any given antenna which may be installed within the Sector Radio Module  20 . 
       FIGS. 10 a  and 10 b    illustrate another aspect of the modulating of the present system, instead of a 120° sector of a cylinder (preferred for three-sector applications), the Sector Radio Module may be configured with a wall mount bracket  40 ,  41 . 
       FIG. 11 a    illustrate that knockout ports  42  may be included in the brackets to facilitate expansion and/or adding extended antennas.  FIG. 12 , illustrates the capability to add or remove a single Sector Radio Module without disrupting operation of other Sector Radio Modules.  FIG. 13  illustrates a mobile application where a three-sector system may be installed on a pneumatic mast. 
     Another benefit of the modularity of the disclosed system is illustrated in  FIG. 14 . In this embodiment, there are three common modules, three Sector Radio Modules  45 ,  46 ,  47  associated with a first carrier, and three Sector Radio Modules  48 ,  49 ,  50  associated with a second carrier. The common modules supply power to the Sector Radio Modules of both carriers. Due to the modularity of the design, back-haul may be established by different links for the different carriers. For example, the back-haul for the first carrier may be established via a back-haul radio link, and back-haul for the second carrier may be established via the optical fiber demarcation of the common modules. Alternatively, instead of stacking Sector Radio Modules from different carriers, a single carrier may stack Sector Radio Modules servicing different frequency bands. For example, three 800 MHz Sector Radio Modules may be stacked on top of three 2.5 GHz Sector Radio Modules.