Patent Application
20080291116
The invention relates to antennas and to communications methods. In particular, but not exclusively, the invention relates to cellular antennas and to communications methods used in such antennas. The communications methods may be used for communication of control data or control of peripheral devices.
Cellular antennas are generally controlled by base station controllers. Each antenna may have an interface for receiving control signals from the base station controller and an antenna controller for receiving the control signals and controlling antenna actuators and the like in accordance with the control signals.
The antenna controller must be capable of controlling each antenna actuator. Furthermore, where sensors are used for monitoring antenna characteristics, the antenna controller must also be capable of communicating with each sensor.
This is problematic because, as antennas become more complex, several peripheral devices such as actuators and sensors are included in the antenna. These devices use a variety of communication protocols, and include modern devices and legacy devices. The antenna controller must be capable of controlling and/or communicating with all of these devices. This not only requires a more sophisticated controller, but also makes retrofitting a new peripheral device into an antenna difficult and time-consuming.
It is an object of the invention to provide improved communications and control systems within antennas. It is another object of the invention to provide a standard communications interface for peripheral devices. It is a further object of the invention to provide a plug and play system for peripheral devices.
There is provided an antenna including a main controller and peripheral devices. The peripheral devices are associated with sub-controllers. A data bus carries commands or data between the main controller and the sub-controllers. There is also provided a system having a communications bus for carrying signals between a master controller and peripheral devices.
In a first exemplary embodiment there is provided an antenna including:
In a second exemplary embodiment there is provided a system including:
The accompanying drawings which are incorporated in and constitute part of the specification, illustrate embodiments of the invention and, together with the general description of the invention given above, and the detailed description of embodiments given below, serve to explain the principles of the invention.
Signals transmitted via the interface over the communications lines 4, 5 pass to a main or master controller 7. The main controller receives commands and other data from an external controller, transmits data to the external controller, transmits commands and other data to peripheral devices and receives data from peripheral devices, as described below.
The antenna may include one or more peripheral devices. These devices may include one or more antenna actuator motors or drivers 8 (including solenoid drivers), for adjustment of components such as phase shifters and mechanical components, for adjustment of antenna characteristics such as azimuth angle, downtilt angle and beam-forming characteristics (beam width, for example).
The peripheral devices may include one or more sensors. The sensors may include a GPS receiver 9, inclinometer 10, azimuth angle sensor 11, as well as position sensors, angle sensors, phase sensors, sun direction sensors (for determining antenna orientation) and any other sensors useful in antennas.
In general, the peripheral devices may include any bus-addressable devices or serial addressable devices.
The peripheral devices may be associated with sub-controllers 12. A sub-controller 12 may be part of a peripheral device or may be formed separately and connected to the peripheral device by any suitable connection. Each sub-controller 12 may include a processor and is adapted to communicate with the main controller. In particular, the sub-controllers are capable of interpreting control data and/or other data sent by the main controller.
Use of sub-controllers 12 allows a standard interface to be provided. Each sub-controller 12 is capable of communications with the main controller 7 over the communications bus described below. This means that peripheral devices (together with sub-controllers) can be added in a ‘plug and play’ manner, without any need for reconfiguring the main controller 7 to communicate with the new peripheral device.
The sub-controllers/peripheral devices may communicate with the main controller using a listen-first, talk-second protocol.
The sub-controllers 12 may communicate with the main controller over communications lines 13 having RJ45 connections. Four peripheral devices may be connected using a 1 by 4 RJ45 connector 14. Alternatively, a larger number of devices may be connected using a 2 by 8 RJ45 distribution hub 15, for example. The RJ45 components may be connected using Ethernet cable, such as CAT5E of CAT6 cable. Other connectors and hubs may be used to connect to a desired number of peripheral devices.
The peripheral devices may include devices which are serially addressable by means of address information in a data packet, as shown in
However, some devices may not be addressable in this way. A hybrid communications bus may be used to address both devices which may be addressed using address information in a data packet and devices which are bus-addressable using address line signals, as described below.
An RJ45 connector includes eight lines. In the hybrid communications bus (see
The four remaining lines (lines 5 to 8) may be used for addressing bus-addressable peripheral devices which cannot be addressed using address data in a data packet. Peripheral devices may be addressed using the address lines in any suitable manner. For example, the first bit (e.g. line 5) may select a bus-addressable mode and the three remaining lines (6 to 8) may select up to eight devices using the eight unique bit combinations 000 to 111.
When the address lines are not required for addressing (i.e. when the device can be addressed using address data in a data packet) they may be used for some auxiliary function.
One address line may be used as a ‘bus-addressable mode’. This address line then carries an on/off signal indicating whether or not the device addressed is a bus-addressable device. In this example when line 5 is low a packet-addressable mode may be selected. The remaining three lines may be used to address a particular bus-addressable device, or for some auxiliary function if a serial addressable device is to be addressed.
Where the address lines are to be used for an auxiliary function, auxiliary signals are communicated over those lines. The auxiliary functions/signals may include the ‘bus-addressable line’ described above; mode data, including peripheral function mode data, memory mode data, or peripheral type data; or peripheral device present signals or indicator signals.
The peripheral function mode data specifies a particular peripheral function, and the sub-controller switches the peripheral function based on the data. Functions may be integrated into a sub-controller ASIC, with the address lines being used to instruct the sub-controller and peripheral device to operate in a certain functional mode. For example, a peripheral device may consist of a multi-sensor module (e.g. having position, phase and inclination sensors). This module may be arranged to receive mode instructions over the address lines, with the mode instructions specifying a certain sensing function (position, phase or inclination). This allows a simplified software interface to be used.
The memory mode data specifies a particular memory range to be accessed by the sub-controller. For example, memory may be provided that is accessible to two or more sub-controllers. Each sub-controller is instructed to access the correct memory table in order to control a particular antenna function correctly. Alternatively, a single sub-controller could be instructed to access different memory tables depending on how a particular peripheral device is to controlled.
The peripheral type data specifies a particular peripheral device type. The peripheral device type could be ‘bus-addressable devices’. Alternatively, there could be a class of non-critical devices which could be switched off if power supply was interrupted or for power-saving. Then a ‘power-critical mode’ could be specified. Peripheral device type could also specify a group of devices using a particular messaging protocol.
The peripheral device present signals are sent from peripheral devices to the main controller to indicate their presence. Indicator signals may also be sent over the address lines. These instruct operation of indicators, such as visual indicators (e.g. LEDs) or audible indicators (e.g. buzzers, speakers etc). This allows feedback on antenna operation when the antenna is enclosed within its housing.
Control instructions and other data may be sent to the microcontroller 43 from an external system. The microcontroller 43 then controls the functioning of the antenna in accordance with these signals. For example, the microcontroller 43 may send control or other data to a peripheral device. This data is sent through a transceiver 45 to the RJ45 four port connector 14, over the communications bus to the peripheral device (not shown in
The power supply received by the RJF45 connector 41 as well as the ground connection are separated and sent to switch 46. The switch is controlled by the microcontroller 43 over control line 47 and supplies power and ground to the RJ45 four port connector 14. A storage device 48, such as a 3V battery, is also recharged by power received from outside the antenna and powers the microcontroller 43.
The systems and antennas described above are capable of controlling motorized actuation for electronic downtilt, azimuth panning and beam forming. They are also capable of operating sensors for detection of antenna position, orientation, phase values and the like. They provide ease of manufacturing, overall usage and installation of peripheral devices. They use cost-effective components such as RJ45 connectors and Ethernet cabling for interconnections and the data bus.
While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.
