Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Application No. 60/707,401 filed Aug. 11, 2005, which is hereby incorporated by reference in its entirety. 
     This application is a continuation of U.S. application Ser. No. 11/463,806, filed on Aug. 10, 2006, now allowed. 
    
    
     FIELD OF INVENTION 
     The present invention relates to the field of wireless communications, and more specifically to a method and system for maintenance of basestation equipment. 
     BACKGROUND OF THE INVENTION 
     Increased capacity demands are driving Multiple Input Multiple Output (MIMO) antenna technology into the basestation architecture. The cabling requirements for conventional ground based electronics and tower mounted antenna, however, become prohibitive with respect to such implementations. As a result, electronic circuitry and other components are being situated at the top or masthead, of a tower. While tower mounting of the basestation Radio Frequency (RF) hardware resolves the cabling issue, maintaining such equipment is expensive. That is because accessing such equipment typically requires specialized cranes or personnel. 
     Therefore there is a need for providing an improved way to maintain basestation equipment mounted on the tower. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a method and system that obviates or mitigates at least one of the disadvantages of existing systems. 
     In accordance with an aspect of the present invention, there is provided a connection module for use in a basestation system. The basestation system includes a basestation module and a translating system for translating at least portion of the basestation module between a first position of a tower and a second position of the tower. The connection module is detachably connected to the portion of the basestation module when the portion of the basestation module is at the second position. 
     In accordance with a further aspect of the present invention, there is provided a translating system for use in a basestation system having a basestation module. The translating system translates at least portion of the basestation module between a first position and a second position. The portion of the basestation module is detachably connected to a connection module when the portion of the basestation module is at the second position. 
     In accordance with a further aspect of the present invention, there is provided a method for maintenance of a basestation system having a translating system and a basestation module. The method comprises the steps of: translating at least portion of the basestation module between a first position and a second position, the first position being different from the second position; and detachably connecting a connection module to the at least portion of the basestation module at the second position. 
     This summary of the invention does not necessarily describe all features of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein: 
         FIG. 1  illustrates an example of a basestation system in accordance with an embodiment of the present invention; 
         FIG. 2  illustrates an example of the basestation system of  FIG. 1  where a basestation radio module is lowered; 
         FIG. 3  illustrates an example of the tower mounted equipment, the basestation module platform and the connection plate of  FIGS. 1-2 ; and 
         FIG. 4  illustrates an example of a plurality of basestation radio modules and mechanism for raising/lowering them and enabling them. 
     
    
    
     DETAILED DESCRIPTION  
     Embodiments of the present invention are described using a basestation having Radio Frequency (RF) equipment placed at the top of a tower when providing a network service. However, the tower mounted equipment may be any equipment other than the RF equipment. 
     In the description below, the terms “top”, “tower top” and “masthead” may be used interchangeably. In the description below, the terms “tower” and “mast” may be used interchangeably. In the description below, the terms “tower mounted equipment” and “masthead equipment” may be used interchangeably. In the description below, the terms “top” and “base” are being used in the general sense to depict two positions of the tower, one position being higher than another position. 
     In the description below, the terms “couple(ed)” and “connect(ed)” may be used interchangeably. These terms may be used to indicate that two or more elements are directly or indirectly in physical or electrical contact with each other. 
       FIG. 1  illustrates an example of a basestation system in accordance with an embodiment of the present invention. The basestation system  2  includes basestation equipment  10  mounted on the top of a tower  4 , hereinafter referred to as tower mounted equipment  10 . The tower mounted equipment  10  may form masthead equipment. The tower  4  may be, but not limited to, a cellular tower. Those of ordinary skill in the art will appreciate that the tower mounted equipment  10  may be located at varying altitudes on the tower. The basestation system  2  may be a basestation tower operating in accordance with, but not limited to, at least one of Wideband Code Division Multiple Access (CDMA), Global System for Mobile (GSM) and Universal Mobile Telecommunications System (UMTS) wireless standards or next generation OFDM based wireless standards. 
     The tower mounted equipment  10  includes one or more basestation modules including a basestation radio module  12  and an antenna system  18 . The antenna system  18  is secured to the top of the tower  4 . Those of skill in the art will understand that the representation of the antenna system  18  is schematic only, and the actual configuration of these elements may take on a variety of configurations. 
     The basestation system  2  includes mechanism for translating the basestation radio module  12  between the top and base of the tower  4  and enabling the tower mounted equipment  10  to operate when the basestation radio module  12  is located at the tower top. 
     The basestation radio module  12  is detachably mounted on a basestation module platform  14 . The basestation radio module  12  may be unloaded from the basestation module platform  14  for maintenance purpose. The antenna system  18  is mounted on a connection plate  16 . The connection plate  16  is secured on the top of the tower  4 . 
     The basestation radio module  12  is detachably coupled to the connection plate  16  at the tower top. The tower mounted equipment  10  is operable when the basestation radio module  12  is connected to the antenna system  18 . The basestation radio module  12  is lowered for its maintenance purpose, while the basestation radio module  12  is raised and connected to the antenna system  18  at the tower top to provide a network service. 
     In  FIG. 1 , the connection plate  16  is formed separately from the antenna system  18 . However, in another example, the connection plate  16  or similar connection mechanism may be formed in the module of the antenna system  18 . In a further example, the connection plate  16  or similar connection mechanism may be formed in any intermediate modules to connect the basestation radio module  12  to the antenna system  18  or any other electronic modules. In a further example, the connection plate  16  or similar connection mechanism may form part of the tower itself In  FIG. 1 , the basestation radio module  12  is connected to the antenna system  18 . However, in another example, the basestation radio module  12  may be connected to any intermediate modules to connect the basestation radio module  12  to the antenna system  18  or any other electronic modules. In  FIG. 1 , the basestation radio module  12  is connected to the connection plate  16 . However, in another example, the basestation radio module  12  may be directly connected to the antenna system  18  or any other electronic modules without using the connection plate  16 . Using the connection plate  16  may however provide increased structural support for the components to which the basestation radio module  12  connects. 
     In  FIG. 1 , one tower mounted equipment  10  is shown. However, the basestation system  2  may include more than tower mounted equipment  10 . Each tower mounted equipment  10  may be located at a different position of the tower  4 . In  FIG. 1 , one antenna system  18  is shown. However, the basestation system  2  may include more than one antenna system  18 . The basestation system  2  may include more than one connection plate  16  for more than one antenna system  18 . In  FIG. 1 , one basestation radio module  12  is shown. However, the basestation system  2  may include more than one basestation radio module  12 . The basestation system  2  may include more than one basestation module platform  14  for more than one basestation radio module  12 . 
     In  FIG. 1 , the basestation radio module  12  is located close to the top of the tower  4 . As shown in  FIG. 2 , the basestation radio module  12  is locatable at a position lower than that of  FIG. 1 . The basestation radio module  12  may be located at the bottom of the tower  4 . However, as described above, it is not required that the basestation radio module  12  be raised or lowered from the absolute bottom or top of the tower respectively. 
     Referring to  FIGS. 1-2 , a location guide  20  is provided to ensure the proper alignment of the electrical connectors in the tower mounted equipment  10 . In  FIGS. 1-2 , the location guide  20  is provided to align the basestation radio module  12  with the connection plate  16 . However, in another example, the location guide  20  may be provided to align the basestation module platform  14  with the connection plate  16 . In a further example, the location guide  20  may be provided to align the basestation radio module  12  or the basestation module platform  14  with a certain position of the tower without using the connection plate  16 . In a further example, the location guide  20  may be provided to align the basestation radio module  12  or the basestation module platform  14  with any electronic modules. In a further example, the basestation system  2  may include more than one tower mounted equipment  10 , and may include more than one location guide  20  for more than one tower mounted equipment  10 . 
     A cabling and pulley system having a cable  40  and a pulley  42  is provided to the basestation system  2 . In  FIG. 1 , one set of the cable  40  and the pulley  42  is provided to each side of the tower mounted equipment  10 . The pulley  42  is connected to the connection plate  16 . However, in another example, the pulley  42  may be connected to the structure of the tower  4 . The cable  40  is connected to the basestation module platform  14 . The basestation radio module  12  is located by raising or lowering the basestation module platform  14 . However, in another example, the housing of the basestation radio module  12  may be directly raised or lowered by the cabling and pulley system. 
     A winch system  44  is provided to wind up the cable  40 . The winch system  44  with the cabling and pulley system enables the basestation radio module  12  to be raised or lowered from the masthead. The winch system  44  may be a manual winch system, an automatic winch system or a combination thereof. The winch system  44  may include a crank to enable manual raising and lowering of the basestation radio module  12 . The winch system  44  may include gear assemblies and may be powered by gas engine, electric motor, hydraulic cylinder, pneumatic, electric, combustion drives, or any other device for providing rotational shaft power. The winch system  44  may include a braking system or ratchet system. 
     The power supply to the winch system  44  need not be situated at the base of the tower  4 . For example, an electric motor may be attached to the top of the tower  4 , in which case a controller (not shown) could be used in conjunction therewith (e.g., a hand held controller, key pad, graphical user interface, etc.). 
     The winch system  44  may employ a detachable motor that can be temporarily connected to rotate the winch mechanism. Depending on the winch mechanism determined for use the detachable motor may take the form of a compressor in the case of a pneumatic or hydraulic system or a rotational motor as in the case in which a cabling system is used. The specifics of the detachable motor would be readily understood by those skilled in the art. 
     Those of skill in the art will understand that the representation of the cable  40 , the pulley  42  and the winch system  44  are schematic only, and the actual configuration of these elements may take on a variety of configurations. Those of skill in the art will understand that mechanism for raising or lowering the basestation radio module  12  may be implemented in various ways other than those shown in  FIGS. 1-2 . Wire hawsers, track, hydraulic cylinder, pneumatics, chain or gear driven arrangements (e.g., worm gear/rack) may be used. 
     In  FIGS. 1-2 , the translating system for translating one basestation module platform  14  is shown. However, in another example, the basestation system  2  may include more than one basestation module platform  14 , and the translating system in the basestation system  2  may translate each basestation module platform  14 . In a further example, the translating system in the basestation system  2  may translate each basestation radio module directly without using the basestation module platform  14 . That is to say, the mechanism for raising and lowering the basestation radio module  12  could be directly connected to the basestation radio module  12 . 
     The basestation system  2  includes a ground based base-band processing unit  30  for transmission and reception of low power digital communications data and power to and from the core network and to and from the tower mounted equipment  10 . The basestation system  2  includes a communication cable  32  from the ground based base-band processing unit  30  to the basestation radio module  12  to convey power and base-band data between the ground and the basestation radio module  12 . 
     In order to prevent damage to the communication cable  32  connecting the basestation radio module  12  to the network connection, the basestation system  2  uses a plug and socket arrangement such that the communication cable  32  is disconnected from the basestation radio module  12  when the basestation radio module  12  is lowered from the tower top, and is connected to the basestation radio module  12  when the basestation radio module  12  is raised and is positioned at the tower top. 
     In  FIGS. 1-2 , the communication cable  32  is attached at the top of the tower  4  to the connection plate  16  so that the basestation radio module  12  can be removed from the basestation module platform  14  and replaced or serviced, without having to bending the communication cable  32  when the basestation radio module  12  is lowered from the top of the tower  4 . 
     In some radio towers there may be a requirement to service multiple operators&#39; equipment. In such a scenario multiple antenna location plates may be present at various heights along the vertical axis of the mast. In such a scenario each operator&#39;s equipment may incorporate a separate winch system for location of the base station equipment. In addition, in the case where the multiple operators use the tower, multiple fixed communication cables may ascend the tower. Those skilled in the art can readily extend the embodiments for maintenance of single basestation to application to multiple platforms at multiple heights to service multiple operators. 
     In  FIGS. 1-2 , single communication cable  32  is shown. However, in an alternative embodiment, more than one communication cable may be used for providing power, data or a combination thereof to the basestation radio module  12 . 
       FIG. 3  illustrates an example of the tower mounted equipment, the basestation module platform and the connection plate of  FIGS. 1-2 . The tower mounted equipment  10  of  FIG. 3  includes a basestation RF transceiver unit  12 A including elements for transmission and reception of cellular RF signals in a multi-sector environment. The basestation RF transceiver unit  12 A is mounted on the basestation module platform  14 . 
     In  FIG. 3 , one RF transceiver unit  12 A is shown as an example of the basestation radio module  12  of  FIG. 1 . However, more than one basestation radio module may be attached to the basestation module platform  14  and be raised or lowered. 
     The tower mounted equipment  10  includes main and diversity antennas  52  that form the antenna system  18  of  FIG. 1  or a part of the antenna system  18 . Those of skill in the art will understand that the representation of the main and diversity antennas  52  is schematic only, and the actual configuration of the main and diversity antennas  52  may take on a variety of configurations. 
     In  FIG. 3 , a connection plate  16 A with blind mate connectors  54  is shown as an example of the connection plate  16  of  FIG. 1 . The connection plate  16 A is secured to the tower top. The main and diversity antennas  52  are mounted on the connection plate  16 A. The connection plate  16 A enables connection of the basestation RF transceiver unit  12 A to the main and diversity antenna  52 . The communication cable  32  is attached to the connection plate  16 A. The connection plate  16 A also enables connection of the basestation RF transceiver unit  12 A to the communication cable  32 . The communication cable  32  is not subject to bending associated with it having to follow the basestation RF transceiver unit  12 A down the tower. 
     In  FIG. 3 , the connection plate  16 A is provided for one basestation RF transceiver unit  12 A. However, the connection plate  16 A may be modified to accommodate multiple RF basestation transceiver units in the case that multiple service providers are connected to the tower. 
     The enclosure of the basestation RF transceiver unit  12 A incorporates blind mate connectors  56  into its top surface. The blind mate connectors  56  in the enclosure of the basestation RF transceiver unit  12 A are coupled with the blind mate connectors  54  in the connection plate  16 A. The blind mate connectors  56  may be encompassed by a rubber ‘O’ ring seal to prevent water ingress. 
     In  FIG. 3 , the blind mate connectors  54  are formed in the connection plate  16 A. However, in another example, the blind mate connectors  54  or any other connection mechanism for connecting the RF transceiver unit  12 A to the antenna  52  may form part of the structure of the tower or may be formed in the housing of any electronic modules. In a further example, the antenna module associated with the antenna  52  may have a connection mechanism and be connected to the RF transceiver unit  12 A without using the connection plate  16 A. 
     In  FIG. 3 , location guide rods  60  and location alignment holes  62  are shown as an example of the location guide mechanism  20  of  FIG. 1 . The location guide rods  60  slide into the location alignment holes  62 . The location alignment holes  62  receive the location guide rods  60  to facilitate blind mate electrical connection of the blind mate connectors  54  and  56 . 
     In  FIG. 3 , four location guide rods and four location alignment holes are shown. However, the number of the location guide rods and the location alignment holes is not limited to four and it may be varied depending on the design and requirements of the basestation. 
     In  FIG. 3 , the location guide rods  60  are attached to the connection plate  16 A and the location alignment holes  62  are arranged in the housing of the basestation RF transceiver unit  12 A. However, in another example, the location guide rods  60  may be attached to the housing of the basestation RF transceiver unit  12 A, and the location alignment holes  62  may be arranged in the connection plate  16 A. 
     In another example, the location guide rods  60  may be attached to the housing of the antenna system (e.g.,  18  of  FIGS. 1-2 ,  52  of  FIG. 3 ) or any other electronic modules. In a further example, the location alignment holes  62  may be formed in the housing of the antenna system (e.g.,  18  of  FIGS. 1-2 ,  52  of  FIG. 3 ) or any other electronic modules. In a further example, the location guide rods  60  or the location alignment holes  62  may be formed in the structure of the tower. 
     In a further example, the location guide rods  60  or the location alignment holes  62  may be arranged in the housing of any basestation module(s) on the basestation module platform  14  other than the basestation RF transceiver unit  12 A. 
     In a further example, the location guide rods  60  and the location alignment holes  62  are arranged such that the location alignment holes  62  are formed in the basestation module platform  14 . This arrangement enables the location alignment holes  52  to be removed from the basestation RF transceiver unit  12 A, and thus it may reduce the size of the basestation RF transceiver unit  12 A. 
     In a further embodiment, the communication cable  32  of  FIGS. 1-3  may be sufficiently flexible to sustain the mechanical bend radii associated with lowering the basestation module from the tower top. 
     In a further embodiment, the tower mounted equipment  10  of  FIGS. 1-2  may use a waveguide rather than the communication cable  32 . 
     Referring to  FIG. 4 , there is illustrated a plurality of basestation radio modules to be raised or lowered. Basestation radio modules  70   1 - 70   N  (N: integer) are mounted on basestation module platforms  72   1 - 72   N , respectively. Each of the basestation radio modules  70   1 - 70   N  may be same or similar to the basestation radio module  12  of  FIGS. 1-2  or the basestation radio module  12 A of  FIG. 3 . Each of the basestation module platforms  72   1 - 72   N  may be same or similar to the basestation module platform  14  of  FIGS. 1-2 . Connection modules  74   1 - 74   N  are provided to the basestation radio modules  70   1 - 70   N , respectively. Each of the connection modules  74   1 - 74   N  may be same or similar to the connection plate  16  of  FIGS. 1-2  or the connection plate  16 A of  FIG. 3 . The connection modules  74   1 - 74   N  may be formed in any electronic modules (e.g., antenna system or any intermediate electronic systems) or form part of the tower. One or more than one communication cable (e.g.,  32  of  FIGS. 1-3 ) may be located at each connection module. 
     Translating systems  76   1 - 76   N  are provided to the basestation radio modules  70   1 - 70   N , respectably. Each of the translating systems  76   1 - 76   N  may include the cabling and pulley system and the winch system  44  of  FIGS. 1-2  or any suitable alternative mechanism for raising or lowering the basestation radio module. The translating systems  76   1 - 76   N  raise or lower the basestation module platforms  72   1 - 72   N , respectively. The translating systems  76   1 - 76   N  may directly raise or lower the basestation radio modules  70   1 - 70   N , respectively, without using the basestation module platforms  72   1 - 72   N . 
     The connection modules  74   1 - 74   N  are detachably connected to the basestation radio module  70   1 - 70   N , respectively and enable them to operate, respectively. The connection modules  74   1 - 74   N  may be located at different positions of the tower, and thus the basestation radio modules  70   1 - 70   N  may be enabled at different positions of the tower. The basestation radio modules  70   1 - 70   N  may be lowered for maintenance at different positions of the tower for maintenance. A location guide (e.g.,  20  of  FIGS. 1-2 ,  60  and  62  of  FIG. 2 ) may be provided for each basestation radio module  70   1 - 70   N  for proper alignment. 
     In  FIG. 4 , “N” is an integer greater than one. However, “N” may be one. In  FIG. 4 , a plurality of translating systems  76   1 - 76   N  are shown separately. However, the plurality of translating systems  76   1 - 76   N  may share some elements, such as power source. 
     There are number of technical advantages to placing RF electronics of a basestation at the tower top. One reason is that a single cable run (e.g.,  32  of  FIGS. 1-3 ) from the base of the tower to the top can be used to convey both power and data. Additionally, such electronics can be used to minimize the number of cables required for MIMO functionality, for example. This eliminates the up front cost and maintenance of multiple high quality RF cable runs normally required. In addition when receiver equipment is located at the tower base, cable loss directly impacts the receiver noise figure. RF power is also dissipated in the cable runs making the power amplifiers less efficient than those placed at the tower top. 
     One issue with tower mounted equipment in conventional systems is the cost to maintain the equipment, as specialized cranes and technicians are typically required to access and service the equipment. Additionally, to avoid such maintenance costs, tower mount electronics component costs are typically increased to realize a higher mean time to breakdown failure rate than ground based equipment. Furthermore, circuit complexity is often increased to provision for redundant circuitry capable of making the tower mounted equipment resilient to circuit component failures. 
     By contrast, according to the embodiments of the present invention, on detection of a fault in the tower mounted equipment a single operator (e.g., person or a control signal to the winch system  44 ) may lower the basestation module from the tower top using the translating mechanism. Once lowered the defective component may be replaced or, alternatively, the entire module may be returned to the vendor for repair. The module may be returned to a factory for testing. New or repaired module then will be raised by the single operator to the tower top for service. 
     The maintenance arrangement/scheme of the embodiments of the present invention removes the requirement for a crane or specialized service personnel to service tower mounted equipment. The arrangement of the embodiments of the present invention removes the insurance costs associated with sending service personnel up the tower. The arrangement of the embodiments of the present invention reduces costs associated with over-provisioning masthead electronics. For example, Mean Time Between Failure (MTBF) of a ground based equipment may be used for the maintenance of the tower mounted equipment because of low cost service mechanism hence reducing initial design costs and specifications. 
     The maintenance arrangement/scheme of the embodiments of the present invention removes the performance degradation in the receiver sensitivity and PA efficiency associated with the cable runs required for ground based radio transceiver modules. 
     The maintenance arrangement/scheme of the embodiments of the present invention enables high capacity data services based on, for example, MIMO OFDM, leading to lower cost per bit for the service. 
     The single communication cable arrangement (e.g.,  32  of  FIGS. 1-3 ) is applicable to cable intensive basestation architecture, such as MIMO that normally requires up to 18 cables, and thus increases the viability of the MIMO technology and the design flexibility of radio modules. 
     The present invention has been described with regard to one or more embodiments. However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims.

Technology Category: h