The disclosed technologies relate generally to wireless communications, and more particularly, to reducing power consumption in mobile wireless communications devices.
The availability of unlicensed millimeter wave (mm-wave) radio frequency (RF) bands is spurring the development of main stream applications that use mm-wave wireless technologies. For example, the Institute of Electrical and Electronics Engineers (IEEE) 802.11ad standard, sometimes referred to as “Wi-Gig”, specifies a data rate of up to approximately 7 Gigabits per second over the 60 GHz frequency band for consumer applications such as wireless transmission of high-definition video.
Wireless communications devices that use high frequency bands, such as the 60 GHz frequency band, often incorporate beam forming technology to achieve a desired level of range and performance. While beam forming can be very effective, implementing beam steering can require increased complexity, for example in the form of phase shifting circuitry, cost and module size. Power consumption is also increased when multiple RF paths are simultaneously active to provide beam forming.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
Embodiments are described with reference to figures in which like reference numerals refer to corresponding elements throughout the figures.
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments. It will be apparent, however, that embodiments may be practiced without these specific details. In other instances, well-known structures and devices are depicted in block diagram form in order to avoid unnecessarily obscuring the embodiments.
It should be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first antenna element could be termed a second antenna element, and similarly, a second antenna element could be termed a first antenna element.
The terminology used in the description herein is for the purpose of describing example embodiments only and is not intended to be limiting. As used in the description of the example embodiments and the appended claims, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will further be understood that the terms “comprises” and/or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
I. Overview
II. Architecture Overview
III. RFIC Antenna Package
IV. Antenna Selection
An approach is provided for managing power consumption in mobile devices configured with a plurality of directional antenna elements and a radio frequency integrated circuit (RFIC). The RFIC is configured to select for use, by the mobile device, a first set of one or more directional antenna elements from the plurality of directional antenna elements based upon selection criteria that include at least one or more power consumption criteria and one or more of one or more performance criteria or one or more interference avoidance criteria. The approach provides sufficient range and performance to allow the mobile device to operate in high frequency bands, such as the 60 GHz frequency band, with reduced power consumption, complexity and size.
Base station 102 and mobile devices 104, 106 are configured with computer hardware, computer software and/or circuitry elements to provide wireless communications. Base station 102 may be configured with various antenna elements to provide wireless communications with mobile devices 104, 106. For example, base station 102 may be configured with one or more antennas for transmitting data and one or more antennas for receiving data. The same or different antennas may be used for transmitting and receiving data, depending upon a particular implementation, and different types of antennas may be used. Example antenna types include, without limitation, patch antennas, dipole antennas, end-fire antennas, Yagi antennas, etc., or any combination thereof. As one non-limiting example, base station 102 may be configured with a first array of patch antennas for transmitting data and a second array of patch antennas for receiving data. The antennas may be located and/or oriented on base station 102 to provide wireless communications with devices located at certain locations/positions with respect to base station 102.
As depicted in
According to one embodiment, mobile devices 104, 106 are not configured with beam forming capability because of size, complexity and power considerations and instead are configured with two or more directional antenna elements of the same or varying type and the capability to select particular directional antenna elements, e.g., one particular directional antenna element, to be used for communications. This approach allows mobile devices 104, 106 to satisfy more stringent size, complexity and power consumption constraints compared to base station 102. The directional antenna elements may provide a radiation pattern in a particular plane and/or direction with respect to mobile devices 104, 106. For example, as depicted in
Mobile devices 104, 106 may include a Radio Frequency Integrated Circuit (RFIC) antenna package that includes a plurality of antenna elements and an RFIC for selecting antenna elements to be used. The antenna elements may be located on the RFIC antenna package to radiate in different directions relative to the RFIC antenna package. Alternatively, one or more antenna elements may be located external to the RFIC antenna package. Further, different types of antenna elements may be used to realize different radiation patterns. Mobile devices 104, 106 may include the same number, type and location of antenna elements, or the number, type and location of antenna elements may be different, depending upon a particular implementation. For example, in the situation where mobile devices 104, 106 are different types of devices, then mobile devices 104, 106 may have a different number, type and/or location of antenna elements. In this example, the physical structure of a mobile device may dictate the location and/or orientation of antenna elements.
While some embodiments are described herein in the context of the plurality of antenna elements being located within the antenna package for purposes of explanation, embodiments are not limited to this arrangement and some or all of the antenna elements may be located external to the RFIC antenna package 200. For example, antenna elements 202-206 may be located on a printed circuit board external to RFIC antenna package 200 that includes RFIC 208. In addition, the plurality of antenna elements 202-206 may be any type of directional antenna elements that may vary depending on a particular implementation.
In the example RFIC antenna package 200, antenna elements 202A, 202B are patch antenna elements pointing downward relative to RFIC antenna package 200 and configured to radiate in a substantially downward vertical direction relative to RFIC antenna package 200. Antenna elements 204A, 204B are Vivaldi end fire antenna elements pointing forward relative to RFIC antenna package 200 and configured to radiate in a substantially horizontal direction relative to RFIC antenna package 200. Antenna elements 206A, 206B are other patch antenna elements pointing upward relative to RFIC antenna package 200 and configured to radiate in a substantially upward vertical direction relative to RFIC antenna package 200. For purposes of explanation, the term “horizontal” refers to a plane parallel to RFIC antenna package 200 regardless of the orientation of RFIC antenna package 200. The term “vertical” refers to a plane perpendicular to the horizontal as just defined. Terms, such as “upward”, “downward”, “above”, “below”, “bottom”, “top”, “forward”, “backward”, “left”, and “right” are defined with respect to the horizontal plane.
In the example RFIC antenna package 200, each antenna element 202-206 comprises separate transmit and receive antennas designated as “A” and “B” respectively. However, each of the plurality of antenna elements can include just a receive antenna, just a transmit antenna, separate transmit and receive antennas, or a combined transmit and receive antenna, depending upon a particular implementation.
The plurality of antenna elements 202-206, when driven by RFIC 208, maximally radiate in certain directions. The direction of maximum radiation for an antenna element is a direction in which the antenna element has its highest gain, for example, as measured as decibels over isotropic (dBi). A higher gain antenna generally provides better link budget than a lower gain antenna but suffers from increased directionally relative to the lower gain antenna. At mm-wave frequencies, each of the high-gain directional antenna elements 202-206 may have a gain of approximately 6 dBi and an antenna beam width of approximately seventy (70) degrees, for example. In contrast, each of the low-gain antenna elements used in a beamforming array at mm-wave frequencies may have a gain of approximately 2 dBi and an antenna beam width of approximately 120 degrees, for example.
RFIC antenna package 200 retains the benefits of better link budgets provided by high-gain directional antenna elements 202-206 without suffering the drawbacks of associated increased directionally by switching between the various antenna elements 202-206 to provide the best communication quality under the current communications conditions (e.g., the current physical orientation of RFIC antenna package 200 relative to another mm-wave transceiver).
While in the example RFIC antenna package 200, antenna elements 202A, 202B, 206A, 206B are patch antenna elements and antenna elements 204A, 204B are Vivaldi end fire antenna elements, the antenna elements 202-206 may be other types of antenna elements depending on a particular implementation. For example, each of antenna elements 202-206 may be the same or different one of a monopole antenna, a dipole antenna, a Yagi antenna, a log periodic dipole antenna, a slot antenna, an annular slot antenna, another type of Vivaldi antenna, or an antenna array thereof. Further, the antenna elements that are used are not limited to a particular polarization and each of the antenna elements 202-206 can be linearly, elliptically, or circularly polarized according to a particular implementation. Further still, while six antenna elements are used in the example RFIC antenna package 200, more or fewer antenna elements, and/or different types of antenna elements, may be used in other embodiments to realize antenna radiation coverage in more or fewer directions.
Although not depicted in
Similarly, to reduce obstruction of the radiation of certain antenna elements pointed toward a ground plane, cutouts or windows may be made in the ground plane. For example, ground plane cutouts or windows may be made for downward pointing antenna element 202. Alternatively, RFIC antenna package 200 (or antenna element 202) may be placed on a printed circuit board of a wireless communications device at a location where the radiation of the antenna element 202 is not obstructed or is only minimally obstructed by a ground plane such as, for example, near or overhanging an edge of the printed circuit board.
According to one embodiment, directional antenna elements on mobile devices are selected for use and/or de-selected for use to achieve a desired radiation pattern, shape, and/or direction. As used herein, the term “selected for use” refers to selecting an antenna element to be used for transmission and/or reception of electromagnetic radiation and the term “de-selected for use” refers to selecting an antenna element to not be used for transmission and/or reception of electromagnetic radiation. For example, selecting an antenna element for use may include activating a power amplifier that drives the selected antenna element and de-selecting for use may include de-activating a power amplifier that drives the de-selected antenna element.
Antenna element selection may be accomplished using a wide variety of techniques that may vary depending upon a particular architecture and implementation. For example, RFIC 208 may be configured to use low noise amplifier (LNA) bank outputs to select and de-select corresponding receiving antenna elements. RFIC 208 may be configured with hardware and/or software interfaces, e.g., application program interfaces (APIs), to allow other components and software processes, either within or external to the antenna apparatus, to issue commands to RFIC 208 to select and de-select antenna elements for use. For example, participant devices in communication with the antenna apparatus may issue commands to RFIC 208 to select and de-select antenna elements for use.
In some implementations, if an antenna is a transmit antenna, then the antenna may be connected to a power amplifier of RFIC 208, and/or if the antenna is a receive antenna, then the antenna may be connected to a low noise amplifier of RFIC 208. In these implementations, RFIC 208 can select and de-select an antenna for use in several different ways. For example, RFIC 208 can turn the biasing (power supply) on for a given low noise amplifier to select a corresponding antenna for use, and RFIC 208 can turn the biasing off for the low noise amplifier to de-select the antenna for use. Similarly, RFIC 208 can turn the biasing on for a given power amplifier to select a corresponding antenna for use, and RFIC 208 can turn the biasing off for the power amplifier to de-select the antenna for use. As another example, a switch circuit may be placed on RFIC 208 between the low noise amplifier and the power amplifier corresponding to an antenna. In this implementation, the switch circuit may be used to select and de-select the antenna for use without manipulating the biasing of the low noise amplifier or the power amplifier.
In step 504, at a second time that is after the first time, a second set of one or more directional antenna elements is selected for use. For example, RFIC 208 may select for use antenna element 204A and de-select for use antenna element 202A. Since antenna elements 202B, 204B, 206A, 206B was previously de-selected for use, a command does not necessarily need to be issued to de-select for use antenna elements 202B, 204B, 206A, 206B. Whether optional commands are issued may depend upon a particular implementation. For example, in some implementations, a command may be issued to select for use or de-select for use a particular antenna element, regardless of whether the particular antenna element is already selected for use or de-selected for use. The radiation pattern of the second set of one or more directional antenna elements predominately radiates in a particular direction and with a particular beam width. For example, the second antenna element may radiate in a predominately forward horizontal direction with an approximately seventy (70) degree beam width, as depicted in
In step 506, at a third time that is after the second time, a third set of one or more directional antenna elements is selected for use. For example, RFIC 208 of RFIC antenna package 200 may select for use antenna element 206A and optionally de-select for use antenna element 204A. The radiation pattern of the third set of one or more directional antenna elements predominately radiates in a particular direction and with a particular beam width. For example, the third set of one or more directional antenna elements may radiate in a predominately upward vertical direction with an approximately seventy (70) degree beam width, as depicted in
Not all of these steps 502, 504, and 506 are required and additional steps may be performed, depending upon a particular implementation. As one example, steps 504 and 506 may be optional in that only one of the antenna elements may be used for an entire communications session. Further, antenna elements may be re-selected for use after previously being selected for use. For example, in step 506, instead of selecting a third set of one or more directional antenna elements for use, the first set of one or more directional antenna elements selected in step 502 may be re-selected for use. This approach allows a mobile device to conduct Wi-Gig wireless communications with other devices without the use of beam forming, which allows for a smaller and less complex implementation that consumes less power compared to wireless devices that implement beam forming.
Antenna element switching as described herein may be employed at any time during communications, for example, during initialization of a communications system, or during active communications sessions. In addition, after an initial set of one or more antenna elements has been selected, a different set of one or more antenna elements may be selected at any time for use in place of the initial set of one or more antenna elements, for example, to accommodate a change in position of communication participants. For example, at a first time, a first antenna element may be selected for communications between a first participant and a second participant, and at a second time that is different than the first time, a second antenna element that is different than the first antenna element may be selected for communications between the first participant and the second participant.
Antenna elements may be selected based upon the particular participants participating in communications. For example, a first antenna element may be selected for communications between a first participant and a second participant and a second antenna element may be selected for communications between the first participant and a third participant, where the second and third participants are different participants. An antenna element may be selected based upon whether a device is transmitting or receiving signals. For example, a first antenna element may be selected for transmission and a different antenna element may be selected for reception.
Embodiments are described herein in the context of three and four antenna elements for purposes of explanation only and embodiments are applicable to antenna arrangements using any number of antenna elements. Antenna arrangements with a greater number of antenna elements may be used to increase the directionality of the apparatus or optimize for certain directions. For example, RFIC antenna package 200 includes three antenna elements 202-206 for optimizing RF communications with another wireless communications device in the upward, downward, and forward directions while RFIC antenna package 250 includes four antenna elements 254A/B, 264A/B, 274A/B, 284A/B for optimizing RF communications in the forward, backward, left, and right directions.
A wide variety of selection criteria may be used to select for use a particular antenna, or a set of two or more particular antennas. Example selection criteria include, without limitation, power consumption, performance criteria and interference avoidance criteria. Selection criteria may be weighted to change the influence that particular selection criteria have on a selection of one or more antennas for use. For example, a first selection criterion may be assigned a higher weight than a second selection criterion to increase the influence on an antenna selection attributable to the first selection criterion relative to the second selection criterion. Thresholds may also be used to ensure that a selection of one or more antennas satisfies the selection criteria used. For example, power consumption and performance selection criteria may be used to select for use one or more antennas that consume the least amount of power while still satisfying a minimum performance threshold. Different selection criteria may be used for different mobile devices depending, for example, on the type of mobile device and/or the importance of power conservation. Selection criteria may be changed over time. For example, a particular mobile device may be configured with initial selection criteria specified by a manufacturer or an administrator and the initial selection criteria may then be changed at a later time. Location may also be used as a selection criterion. For example, the known position of a base station, e.g., via global positional satellite (GPS) coordinates, relative to a mobile device, may be used to select one or more antennas to be used for communications.
According to one embodiment, a mobile device is configured to select for use a single directional antenna for communication with another device to reduce power consumption. The selection may be specific to the other device. For example, referring to
The selection of directional antenna elements may be made at any time that may vary depending upon a particular implementation. When mobile device 104 is first powered on, or when communications with other devices are to be initiated, mobile device 104 may use a default configuration that specifies one or more particular directional antenna elements to be used for communications. The default configuration may be general, or may be specific to a particular device. For example, a default configuration may specify that a set of one or more directional antenna elements are to be used in all situations, regardless of the other devices that might in communications. As another example, when it is known that communications will be conducted with a particular device, such as base station 102, then the default configuration may specify that a particular directional antenna, or antennas, are to be used. One or more antennas selected for use in accordance with a default configuration may be changed at any time. For example, a first directional antenna may be selected for use in accordance with a default configuration and then a second directional antenna may be immediately, or later, selected for use instead of the first directional antenna. This may be done to provide lower power consumption and better performance and/or interference avoidance. Further directional antenna selections may be made at any time.
According to one embodiment, scanning is used to evaluate the performance of each of a plurality of directional antenna elements and the directional antenna providing the lowest power consumption and the best performance and/or interference avoidance is selected for use. Scanning may include using each of the available directional antenna elements one at a time, or scanning may include using more than one of the available directional antenna elements at a time. Antenna performance may be measured according to a wide variety of criteria that may vary depending upon a particular implementation. For example, error rates, e.g., packet error rates, and/or signal-to-noise ratios may be used to evaluate antenna performance. Scanning may be useful, for example, to identify one or more antennas that are currently blocked and therefore should not be used for communications at the current time. Once the performance of the available directional antenna elements has been determined, then one or more directional antenna elements may be selected for use. According to one embodiment, the one or more directional antenna elements selected for use consume the least amount of power among the available directional antenna elements, while still satisfying any applicable performance and/or interference avoidance criteria.
According to one embodiment, mobile devices may be configured to select directional antenna elements for use according to an operating mode. One example mode is a low power mode in which a single directional antenna is selected as previously described herein. The low power mode may be used, for example, to transfer video or audio data between communications devices. Another example mode is a coverage mode in which multiple directional antenna elements are used. The coverage mode may be used, for example, to transfer data files between communications devices. Similarly, in an accuracy mode, multiple directional antenna elements are used with intelligent beam forming to provide better coverage.
The approaches described herein may be selectively implemented on particular devices. For example, the approaches may be implemented on mobile devices, such as mobile devices 104, 106, where lower power consumption is desirable, but not implemented on devices, such as base station 102, where power consumption attributable to multiple active antenna elements is not a concern. As another example, the approaches may be implemented on mobile device 104, but not mobile device 106. The use of the approaches described herein may be determined, for example, based upon a configuration of a mobile device, or the use may be selectable by a user, for example, via an application on the mobile device.
In the foregoing specification, embodiments are described with reference to numerous specific details that may vary from implementation to implementation. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indicator of the scope of the invention, and what is intended by the applicants to be the scope of the invention, is the literal and equivalent scope of the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction.