Patent Application
20090016721
Some network devices, such as Optical Network Terminals (ONTs), are equipped with batteries and Battery Backup Units (BBUS) to support continued service in an event of a primary power interruption. The BBU is a device that manages the power feed to an ONT. Power can come from a commercial source, such as a home alternating current (AC) outlet or the battery. Batteries have limited service and shelf life, so when batteries expire, customers are urged to perform maintenance by returning, recycling or disposing them and installing a new battery. The manufacturer(s) of network devices, batteries or battery backup units are generally not burdened with maintenance after field deployment, but the maintenance impacts the customers, such as service providers and the end users (e.g., subscribers) of the service providers.
BBUs communicate in a unidirectional manner with an ONT to send information to the ONT for transmitting to a technician. Moreover, it is difficult to verify installation integrity of a BBU telemetry cable between the BBU and the ONT.
A method and corresponding apparatus for monitoring a battery backup unit with at least one battery in accordance with example embodiments of the invention, are provided. An example embodiment includes enabling a battery backup unit and communicating in a bidirectional manner between the battery backup unit and a device external from the battery backup unit to receive status request signals and provide information responsive thereto about the battery backup unit, including information about the at least one battery.
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating example embodiments of the invention.
A description of example embodiments of the invention follows.
Current Passive Optical Network (PON) (e.g., broadband PONs (BPON), gigabit PONs (GPON), and other derivatives) architecture may employ hardware (e.g., Battery Backup Unit (BBU) and Optical Network Terminal (ONT) Power Supply Unit (OPSU) to manage and regulate power to the fiber terminating equipment (e.g., ONT) at the customer premise. An OPSU may also be referred to as a Serial ONT Power Supply (SOPS) as is known in the art. For the sake of convenience and readability, the term OPSU is used throughout the specification, but one skilled in the art will readily recognize that principles of the invention are also applicable to the SOPS. Architecture implementations derive primary power from the residential utility power grid and can seamlessly transition to a battery when utility power is lost.
It would be useful for manufacturers of network devices and BBUs to consider scenarios that can improve the products such that manufacturers, service providers, and end users can easily manage them. A battery backup unit (BBU) may also be referred to as a serial battery backup power supply (SBBPS) as is known in the art. For the sake of convenience and readability, the term BBU is used throughout the specification, but one skilled in the art will readily recognize that principles of the invention are also applicable to the SBBPS. Example embodiments of the invention may include one or more of these useful improvements: bidirectional communications regarding the state of the power equipment (e.g., OPSU, BBU, and battery), installation integrity, real-time troubleshooting, and software upgrades. Currently, unidirectional communications between the BBU and the ONT cannot provide the state of the power equipment (e.g., OPSU, BBU, and battery), installation integrity, real-time troubleshooting, and software upgrades. For example, if a technician wants to learn more about the state of the power equipment (e.g., OPSU, BBU, and battery), he/she may have to go to the end user's house to take measurements of the power equipment.
An example embodiment of the invention provides for bidirectional communications with a BBU. The bidirectional communications may be used to monitor, for example, status of the BBU or remaining power that can be provided by the BBU. The BBU may include at least one battery, a bidirectional communications bus, and a control unit. The control unit may be coupled to the at least one battery and the bidirectional bus. The control unit may communicate in a bidirectional manner with a device external from the battery backup unit, such as an ONT, which is also coupled to the bidirectional communications bus to receive status request signals and provide information responsive thereto about the battery backup unit. The information about the battery backup unit includes information about the at least one battery, temperature, current, and voltage. The control unit may include at least one line coupled to the control unit to receive the status request signals and provide bidirectional communications responsive thereto with the device external from the battery backup unit in addition to bidirectional communications via the bidirectional communications bus.
The BBU may include a battery recharger to recharge the at least one battery when a primary power source (e.g., local AC power) is ON. The BBU may further include at least one interface port coupled to the communications bus to provide bidirectional communications with the device external from the battery backup unit. The at least one interface port may be a parallel, serial, or wireless interface configured to receive the status request signals and provide information responsive thereto with another device at the battery backup unit other than the device configured to receive backup power from the battery backup unit.
The battery backup unit may further include a primary power monitoring unit coupled to a primary power source to monitor power or status information of the primary power source. The primary power source may be an Optical Network Terminal (ONT) Power Supply Unit (OPSU). The primary power monitoring unit may include an alternating current (AC) monitoring circuit to monitor AC input voltage or current and provide information to the device external from the battery backup unit about the AC input voltage or current. The primary power monitoring unit may further include a direct current (DC) monitoring circuit to monitor DC output voltage or current and provide information to the device external from the battery backup unit about the DC input voltage or current.
The example network 100 of
The ONTs 130 may be equipped with batteries or battery backup units (BBUs) 135, interchangeably referred to herein as a BBU 135. The BBU 135 may be an uninterruptible power supply unit. In an event an ONT 130 equipped with a BBU 135 experiences an interruption in primary power (e.g., local AC power/primary power source 132), the ONT 130 may enable the BBU 135 or otherwise accept receipt of power from the BBU 135 to maintain services until the primary power source 132 is restored or the BBU 135 is drained of stored energy. On legacy products, the ONT 130 may regulate power between the BBU 135 and an Optical Network Terminal (ONT) Power Supply Unit (OPSU) 134. On newer designs, the BBU 135 may provide other operations, such as regulating the power feed.
As described above in reference to
The following discussion of control unit 420 is made with reference to a particular example embodiment. However, one skilled in the art will understand that the invention is not limited to this particular example embodiment. The control unit 420 may be a central processing unit (e.g., STMicroelectronics® part number ST 72F324K2T6) that has a full 8-bit architecture and contains six internal registers allowing efficient 8-bit data manipulation. One way of providing access to the control unit 420 to provide bidirectional communications is to add a sixth trace or wire 445-6 to a five trace communications bus 440 that is currently used in installation. In current configurations, four of the six traces or wires 445-1 . . . 4 are used for unidirectional telemetry signals (i.e., on battery, low battery, failed battery, and missing battery). A fifth trace or wire 445-5 carries a ground reference. Each signal is carried by a separate trace or wire 445-1 . . . 5 from the BBU 410 to the ONT 450. These unidirectional telemetry signals are managed (e.g., raised and cleared) by the BBU 410. The provisioning of alarm signal thresholds and algorithmic models for managing these signals are predefined by factory setting(s). Currently, the sixth trace or wire 445-6 is non-existent. The sixth trace or wire 445-6 is unneeded in previous implementations of BBU's 410 because five traces or wires 445-1 . . . 5 are all that the control unit 420 uses or needs to transmit its unidirectional data.
An external cable 441 with wires 446-1 . . . 5 previously existed to carry unidirectional communications is connected between an interface 465 at the BBU 410 and an interface 466 at the ONT 450. A sixth wire 446-6 may be added to support an example embodiment of the invention to carry bidirectional communications. The sixth wire 446-6 may connect the interface 465 of the BBU 410 and the interface 466 of the ONT 450 to support bidirectional communications. In past implementations of BBUs, the control unit 420 is programmed to communicate unidirectionally since higher level functions that can be achieved through bidirectional communications have been considered unnecessary; changes with batteries are so slow paced that periodic status reports from the control unit 420 have been more than adequate for monitoring purposes. However, unexpected results have been found through use of bidirectional communications, such as realizing value of on-demand learning of a state of the power equipment (e.g., OPSU, BBU, and battery), immediate determination of installation integrity, real-time troubleshooting, and downloading and testing software upgrades. The sixth wire 446-6 therefore may be implemented for bidirectional communications. Another example of providing access to the control unit for bidirectional communications is to replace the sixth trace or wire 445-6 with two wires (not shown) connected to a bidirectional serial interface (not shown).
A Joint Test Action Group (JTAG) header (not shown) may be used to program the control unit 420 to support bidirectional communications. Further, instead of the sixth trace or wire 445-6 going from the interface 465 to the control unit 420, the sixth trace or wire 445-6 may be connected to a pin of the JTAG header after programming, and a pin of the control unit 420 may then be used to support the bidirectional communications via the JTAG header and the sixth trace or wire 445-6 with the ONT 450.
Bidirectional communications are useful in many ways. The following examples of the usefulness of bidirectional communications are intended as illustrations and are not intended to be exclusive or limiting in anyway. A first way bidirectional communications can be used is to verify installation integrity. Current installation verification mechanisms rely on a technician to inspect visually the installation of hardware and telemetry harnesses between the BBU 410 and the ONT 450. Visual inspection can be challenging and time consuming for the technician since the BBUs 410 and ONTs 450 are typically located in different parts of a customer's home. For example, there are scenarios in which the BBUs 410 are installed in a garage and the ONTs 450 are installed outside of a house. In addition, the bidirectional communications bus/wiring harnesses 441 may be built at the site. A technician for example, may reverse the wiring harnesses 441 or accidentally crimp the harnesses 441. Therefore, wire orientations and improper connector termination are known to be installation issues. The bidirectional communications may allow the technician (either at the customer's site or remotely via a management system) to initiate a telemetry self test. The self test instructs the BBU 410 via the control unit 420 to generate momentarily and clear each telemetry alarm in a pre-defined sequence. The test may be designed to pass if each signal is raised and cleared in the order expected. Failure of the test may indicate a possible telemetry wiring issue.
A second way that bidirectional communications may be useful is in support of real-time troubleshooting. Current troubleshooting methods and procedures are limited to evaluating current and historical alarms as discussed above. Through use of the bidirectional communications, however, a technician may initiate diagnostic tests, such as “battery test,” on demand. The bidirectional communications may also be used to allow the technician to recover current and historical BBU 410 logs on demand from a storage unit 430 coupled to the control unit 420 of the BBU 410 or integrated in the control unit 420. These logs may include information on recent battery tests and/or input and output voltage or current measurements. The information may be used to quantify the battery 425 capacity, instead of a simple pass/fail test. The information may also include quantifying the battery 425 temperature.
Moreover, a telecommunications company (e.g., service provider responsible for the ONT 450) may use the information about the battery 425 to alert the end user to replace the battery 425. The logs may be archived for evidence available for potential litigation if the end user does not replace the battery 425 and a catastrophic event occurs, allegedly caused by an old or defective battery. The logs may also be used to predict when the battery 425 may fail rather than having to wait for the actual failure. This is useful at an onset of inclement weather (e.g., winter) when replacing the battery 425 may be difficult. The ONT 450 may be programmed to pull and archive the logs periodically from the BBU 410 for future analysis.
A third way that bidirectional communications may be useful is for software upgrades. Typically, provisioning settings in the BBU 410 is done at a manufacturer's facility. Any modification of these settings once the equipment is deployed to the field is generally time consuming and expensive. For example, a technician may be dispatched to the customer site to remove and return the BBU 410 to the manufacturer for modification. Another example may require the end user to remove and mail the BBU 410 back to the manufacturer. Bidirectional communications may allow a technician to download software upgrades to the BBU 410 remotely without the need to remove the BBU 410 and mail it back to the factory.
A fourth way that bidirectional communications may be useful is to aid in forcing the BBU 410 to reset. Instead of a service provider calling the end user to ask him/her to remove the battery power, the BBU 410 may allow a technician to remotely initiate a reset of the BBU 410.
Continuing to
The battery 425 may be a nickel metal hydride, nickel-cadmium, lithium-ion, or lithium polymer cell, as well as any other conventional, newly developed, or later developed rechargeable battery. The BBU 410 may also include a DC-DC converter 435 to convert the +48V to +12V for the ONT 450. Although
As shown in
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
It should be understood that any of the above-described flow diagrams of
It should be further understood that the flow diagrams of
It should be further understood that the PON can be other network types, and the ONT can be any form of network node in a network employing a power backup unit, which may be a battery backup unit or other power storage device (e.g., capacitor) backup unit or self-generating power device, such as a solar panel or fuel cell.
