Power management in a transmitter

<u>Field of the Invention</u>

The present invention relates generally to power management techniques and, more particularly, to power management techniques in network devices, such as gigabit Ethernet cards.

<u>Background of the Invention</u>

Portable electronic devices, such as portable computers, personal digital assistants (PDAs), and cellular telephones, typically include a battery to provide power to the portable device. In order to maximize battery life and avoid loss of data, most portable electronic devices include power management techniques. Battery life is typically addressed by reducing the power consumption of a device when the device is not used for a period of time, such as shutting down the device or entering a low power consumption state (e.g., a sleep mode). Further, portable electronic device that include a memory, such as a random access memory (RAM), must retain some minimum battery power level to preserve the stored data. Thus, to avoid loss of data, such electronic devices typically perform a controlled shut down before a certain minimum battery level is reached.

Power management techniques thus reduce power consumption at the expense of one or more of system specifications, such as speed, noise, battery life or processing speed. Most power management techniques only define active and power saving states for network devices based on network activity and device usage. For example, when there is no traffic on both the receive and transmit paths for a predefined minimum time period, the power management software will typically shut down the device or enter a low power consumption state.

A need therefore exists for a method and apparatus for providing improved power management techniques that reduce power consumption by selecting a transmission mode with reduced power consumption as the battery level gets lower.

European Patent Application No. <patcit id="pcit0001" dnum="EP1292040A"><text>EP-A-1292040</text></patcit> discloses a communication control nit (11) that determines a wireless communication stop period upon executing intermittent wireless communication, on the basis of the retaining amount detected by a battery remaining amount detection unit (7), and executes intermittent wireless communication with another apparatus in accordance with the determined wireless communication stop period.

Summary of the Invention

Generally, a method and apparatus are disclosed for power management of an electronic device.

In accordance with one aspect of the invention there is provided a method for power management in an electronic device that communicates over a network according to claim 1.

Further in accordance with the invention there is provided an electronic device according to claim 6.

Still further in accordance with the invention there is provided a computer program for an electronic device that communicates over a network according to claim 9.

The present invention reduces power consumption of an electronic device that communicates over a network by selecting a transmission mode with reduced power consumption as the battery level gets lower. A disclosed power management process monitors the battery level of an electronic device and selects a transmission mode (e.g., a transmission rate) with a lower power consumption when the battery power level reaches one or more predefined threshold levels.

A more complete understanding of the present invention, as well as further features and advantages of the present invention, will be obtained by reference to the following detailed description and drawings.

Brief Description of the Drawings

<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> illustrates an exemplary network environment in which the present invention can operate;</li><li><figref idref="f0002">FIG. 2</figref> is a schematic block diagram of an exemplary electronic device incorporating features of the present invention;</li><li><figref idref="f0003">FIG. 3</figref> is a sample table describing an exemplary implementation of a power management database of <figref idref="f0002">FIG. 2</figref>; and</li><li><figref idref="f0004">FIG. 4</figref> is a flow chart describing an exemplary implementation of a power management process that is implemented by an electronic device of <figref idref="f0002">FIG. 2</figref>.</li></ul>

Detailed Description

The present invention provides improved power management techniques that reduce power consumption by selecting a transmission mode with reduced power consumption as the battery level gets lower. A power management process 400, discussed below in conjunction with <figref idref="f0004">FIG. 4</figref>, monitors the battery level of an electronic device and selects a transmission mode (e.g., a transmission rate) with a lower power consumption when the battery power level reaches one or more predefined threshold levels. In this manner, the power management process 400 keeps the network link active for receiving and transmitting packets, while reducing the power consumption. The exemplary power management techniques are meant to supplement the conventional power management techniques that would be commonly found in commercial electronic devices 200.

<figref idref="f0001">FIG. 1</figref> illustrates an exemplary network environment in which the present invention can operate. As shown in <figref idref="f0001">FIG. 1</figref>, one or more electronic devices 200-1 through 200-N (hereinafter, collectively referred to as electronic devices 200, discussed below in conjunction with <figref idref="f0002">FIG. 2</figref>, communicate over a network 120. The network 120 may be embodied as any private or public wired or wireless network, including the Public Switched Telephone Network, a Private Branch Exchange switch, a wireless local area network (WLAN), for example, in accordance with one or more of the IEEE 802.11 a/g/b standards, Internet, or cellular network, or some combination of the foregoing. While the present invention is illustrated using a client side implementation, where the features of the present invention are resident on the electronic device 200, the features and functions of the present invention may be deployed on a number of distributed devices or servers, as would be apparent to a person of ordinary skill in the art.

<figref idref="f0002">FIG. 2</figref> is a schematic block diagram of an exemplary electronic device 200 incorporating features of the present invention. The electronic device 200 may be any battery operated device that communicates over a network 120, such as a portable computer, personal digital assistant (PDA) or cellular telephone. As shown in <figref idref="f0002">FIG. 2</figref>, the exemplary electronic device 200 includes a processor 210 and a memory 220, in addition to other conventional elements (not shown). The processor 210 operates in conjunction with the memory 220 to execute one or more software programs. Such programs may be stored in memory 220 or another storage device accessible to the electronic device 200 and executed by the processor 210 in a conventional manner.

For example, the memory 220 may store a power management database 300 and a power management process 400. Generally, the power management database 300 identifies an appropriate transmission mode (e.g., a transmission rate) for one or more predefined battery power threshold levels. The power management process 400 monitors the battery level of an electronic device 200 and selects a transmission mode with a lower power consumption when the battery power level reaches one or more predefined threshold levels. For example, the power management process 400 can monitor the system battery power level and reduce the network link rate, for example, from 1Gbps to 10 Mbps, as the battery power level gets lower.

<figref idref="f0003">FIG. 3</figref> is a sample table describing an exemplary implementation of a power management database 300 incorporating features of the present invention. As previously indicated, the power management database 300 identifies an appropriate transmission mode (e.g., a transmission rate) for one or more predefined battery power threshold levels. As shown in <figref idref="f0003">FIG. 3</figref>, the power management database 300 includes a number of records 301-305, each associated with a different battery level threshold range. For each threshold range identified in field 330, the power management database 300 identifies a corresponding bit rate and transmission mode in fields 340, 350, respectively.

It is noted that the table-based implementation described herein is for illustration. The power management techniques described herein can be implemented in various ways, consistent with the scope of the present invention. For example, in a dynamic implementation, the power management process 400, discussed below, can periodically collect data evaluating the power consumption of the electronic device 200 in various transmission modes, and use the collected information to establish one or more dynamic thresholds, without the creation of an explicit power management database 300. In a further variation, the collected data can be used to populate the power management database 300.

The exemplary data recorded in the power management database 300 may be associated, for example, with a portable computer, such as a laptop, having a 10/100/1000BaseT gigabit Ethernet card. The exemplary device can have a maximum power mode that is employed when the battery level is above a predefined threshold, and having a maximum throughput, such as 1000BaseT, 1 Gbps, full duplex transmission. When the battery level falls below the predefined threshold, the device 200 can switch to a lower power mode, having a reduced throughput, such as 10BaseT, 10Mbps, half duplex transmission.

<figref idref="f0004">FIG. 4</figref> is a flow chart describing an exemplary implementation of a power management process 400 incorporating features of the present invention. Generally, the power management process 400 monitors the battery level of an electronic device 200 and selects a transmission mode with a lower power consumption when the battery power level reaches one or more predefined threshold levels. For example, the power management process 400 can monitor the system battery power level and reduce the network link rate, for example, from 1 Gbps to 10 Mbps, as the battery power level falls below a threshold.

The exemplary power management process 400 can be implemented, for example, in a device driver and can be selectively enabled by the user, for example, using a control panel interface of an operating system, such as Microsoft Windows™. When enabled, the power management process 400 may provide a power savings of up to a factor of five, relative to no power management. More importantly, the power management process 400 reduces the system activities caused by network traffic and helps to extend battery life.

As shown in <figref idref="f0004">FIG. 4</figref>, the power management process 400 initially performs a test during step 410 to determine if the power management process has been enabled. If it is determined during step 410 that the power management process has not been enabled, then program control returns to step 410 until the power management process is enabled.

Once it is determined during step 410 that the power management process has been enabled, then the battery level of the electronic device 200 is evaluated during step 420. A test is performed during step 430 to determine if the measured battery level falls below a predefined threshold level, such as a level identified in the power management database 300. If it is determined during step 430 that the measured battery level has not fallen below a predefined threshold level, then program control returns to step 410 and continues in the manner described above.

If, however, it is determined during step 330 that the measured battery level has fallen below a predefined threshold level, then a new transmission mode with reduced power consumption is selected during step 440, for example, based on information contained in the power management database 300.

System and Article of Manufacture Details

As is known in the art, the methods and apparatus discussed herein may be distributed as an article of manufacture that itself comprises a computer readable medium having computer readable code means embodied thereon. The computer readable program code means is operable, in conjunction with a computer system, to carry out all or some of the steps to perform the methods or create the apparatuses discussed herein. The computer readable medium may be a recordable medium (e.g., floppy disks, hard drives, compact disks, or memory cards) or may be a transmission medium (e.g., a network comprising fiber-optics, the world-wide web, cables, or a wireless channel using time-division multiple access, code-division multiple access, or other radio-frequency channel). Any medium known or developed that can store information suitable for use with a computer system may be used. The computer-readable code means is any mechanism for allowing a computer to read instructions and data, such as magnetic variations on a magnetic media or height variations on the surface of a compact disk.

The computer systems and servers described herein each contain a memory that will configure associated processors to implement the methods, steps, and functions disclosed herein. The memories could be distributed or local and the processors could be distributed or singular. The memories could be implemented as an electrical, magnetic or optical memory, or any combination of these or other types of storage devices. Moreover, the term "memory" should be construed broadly enough to encompass any information able to be read from or written to an address in the addressable space accessed by an associated processor. With this definition, information on a network is still within a memory because the associated processor can retrieve the information from the network.

It is to be understood that the embodiments and variations shown and described herein are merely illustrative of the principles of this invention and that various modifications may be implemented by those skilled in the art without departing from the scope of the invention.