Patent Application
20140274111
1. Field of the Invention
Aspects of the disclosure are directed to transfer of accurate location information between mobile devices.
2. Description of the Related Art
Modern user devices, such as cell phones, smart phones, tablet computers, personal digital assistants (PDAs), and the like, are typically able to accurately determine their location based on signals received from one or more radio transmitters using some form of multilateration or trilateration. The transmitters can be satellites in a global navigation satellite system (GNSS), such as the global positioning system (GPS), or terrestrial radio frequency (RF) transmitters, such as cellular base stations, local wireless network access points, and the like. Local wireless network access points can include wireless local area network (WLAN) access points, WiFi access points, femto cells, Bluetooth® transmitters, near field communication transmitters, and the like.
Maintaining an accurate location inside a building or other enclosed structure, such as a subway system, can be challenging in the absence of local wireless network access points that have previously been accurately positioned using, for example, crowd sourcing. In such an environment, it may be impossible to use a GNSS or assisted GNSS (A-GNSS) due to excessive attenuation of the satellite signals. Positioning using signals from outdoor macro cells may be just as difficult due to very limited building penetration. While inertial navigation (using internal sensors such as accelerometers, magnetometers, gyroscopes, etc.) can be used to accurately track location when the user device first enters the enclosed structure by updating the last accurate location estimate obtained outside of the structure, the gradual accumulation of small errors in sensor measurements eventually renders any location estimate too inaccurate for many uses.
Aspects of the disclosure are directed to determining a location of a user equipment (UE) in a poor positioning environment based on locations of one or more devices. A method for determining a location of a UE in a poor positioning environment based on locations of one or more devices includes receiving, from a first device, a first location and a first location uncertainty of the first device, determining whether or not the first location uncertainty is less than a location uncertainty of the UE, and if the first location uncertainty is less than the location uncertainty of the UE, determining the location of the UE based on the location of the first device and a distance to the first device.
An apparatus for determining a location of a UE in a poor positioning environment based on locations of one or more devices includes logic configured to receive, from a first device, a first location and a first location uncertainty of the first device, logic configured to determine whether or not the first location uncertainty is less than a location uncertainty of the UE, and logic configured to determine the location of the UE based on the location of the first device and a distance to the first device if the first location uncertainty is less than the location uncertainty of the UE.
An apparatus for determining a location of a UE in a poor positioning environment based on locations of one or more devices includes means for receiving, from a first device, a first location and a first location uncertainty of the first device, means for determining whether or not the first location uncertainty is less than a location uncertainty of the UE, and means for determining the location of the UE based on the location of the first device and a distance to the first device if the first location uncertainty is less than the location uncertainty of the UE.
A non-transitory computer-readable medium for determining a location of a UE in a poor positioning environment based on locations of one or more devices includes at least one instruction to receive, from a first device, a first location and a first location uncertainty of the first device, at least one instruction to determine whether or not the first location uncertainty is less than a location uncertainty of the UE, and at least one instruction to determine the location of the UE based on the location of the first device and a distance to the first device if the first location uncertainty is less than the location uncertainty of the UE.
A more complete appreciation of aspects of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings which are presented solely for illustration and not limitation of the disclosure, and in which:
Various aspects are disclosed in the following description and related drawings. Alternate aspects may be devised without departing from the scope of the disclosure. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.
The words “exemplary” and/or “example” are used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” and/or “example” is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term “aspects of the disclosure” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation.
Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. Additionally, these sequence of actions described herein can be considered to be embodied entirely within any form of computer readable storage medium having stored therein a corresponding set of computer instructions that upon execution would cause an associated processor to perform the functionality described herein. Thus, the various aspects of the disclosure may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspects may be described herein as, for example, “logic configured to” perform the described action.
A client device, referred to herein as a user equipment (UE), may be mobile or stationary, and may communicate with a radio access network (RAN). As used herein, the term “UE” may be referred to interchangeably as an “access terminal” or “AT,” a “wireless device,” a “subscriber device,” a “subscriber terminal,” a “subscriber station,” a “user terminal” or UT, a “mobile terminal,” a “mobile station” and variations thereof. Generally, UEs can communicate with a core network via the RAN, and through the core network the UEs can be connected with external networks such as the Internet. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over wired access networks, WiFi networks (e.g., based on IEEE 802.11, etc.) and so on. UEs can be embodied by any of a number of types of devices including but not limited to PC cards, compact flash devices, external or internal modems, wireless or wireline phones, cellular phones, smart phones, tablet computers, laptops, and so on. A communication link through which UEs can send signals to the RAN is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the RAN can send signals to UEs is called a downlink or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein the term traffic channel (TCH) can refer to either an uplink/reverse or downlink/forward traffic channel.
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UEs 1 to 3 can measure radio signals received from one or more satellites 130, RAN 120, and/or access point 125 and one or more other similar access points to determine their positions. The radio signals being measured may be intended primarily to support communication among UEs or may be intended primarily to support positioning of UEs, or may serve both purposes. In the example of
The wireless communications system 100 is an example of a “good” positioning environment, or just a “good environment,” because a UE can accurately determine its position from satellite, cellular, and/or local wireless network positioning systems as described above. A good environment is typically an outdoors environment, where the UE can receive positioning signals with little or no attenuation.
Note that in this disclosure, the terms “position” and “location” are used interchangeably, and can refer to an absolute geographic position or a position relative to other points.
While internal components of UEs such as the UEs 200A and 200B can be embodied with different hardware configurations, a basic high-level UE configuration for internal hardware components is shown as platform 202 in
Accordingly, an aspect of the disclosure can include a UE (e.g., UE 200A, 200B, etc.) including the ability to perform the functions described herein. As will be appreciated by those skilled in the art, the various logic elements can be embodied in discrete elements, software modules executed on a processor or any combination of software and hardware to achieve the functionality disclosed herein. For example, ASIC 208, memory 212, API 210 and local database 214 may all be used cooperatively to load, store and execute the various functions disclosed herein and thus the logic to perform these functions may be distributed over various elements. Alternatively, the functionality could be incorporated into one discrete component. Therefore, the features of the UEs 200A and 200B in
The wireless communication between the UEs 200A and/or 200B and the RAN 120 can be based on different technologies, such as CDMA, WCDMA, time division multiple access (TDMA), frequency division multiple access (FDMA), Orthogonal Frequency Division Multiplexing (OFDM), GSM, or other protocols that may be used in a wireless communications network or a data communications network. As discussed in the foregoing and known in the art, voice transmission and/or data can be transmitted to the UEs from the RAN using a variety of networks and configurations. Accordingly, the illustrations provided herein are not intended to limit the aspects of the disclosure and are merely to aid in the description of various aspects of the disclosure.
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Generally, unless stated otherwise explicitly, the phrase “logic configured to” as used throughout this disclosure is intended to invoke an aspect that is at least partially implemented with hardware, and is not intended to map to software-only implementations that are independent of hardware. Also, it will be appreciated that the configured logic or “logic configured to” in the various blocks are not limited to specific logic gates or elements, but generally refer to the ability to perform the functionality described herein (either via hardware or a combination of hardware and software). Thus, the configured logics or “logic configured to” as illustrated in the various blocks are not necessarily implemented as logic gates or logic elements despite sharing the word “logic.” Other interactions or cooperation between the logic in the various blocks will become clear to one of ordinary skill in the art from a review of the aspects described below in more detail.
The various aspects may be implemented on any of a variety of commercially available server devices, such as server 400 illustrated in
A poor positioning environment, or “poor environment,” is one in which a user device cannot typically determine its location from satellite, cellular, and/or local wireless network positioning systems, such as GNSS, A-GNSS, AFLT, OTDOA, E-CID, WiFi or the like. A poor positioning environment will typically be an indoor or underground location, such as a building or subway system, due to excessive attenuation of positioning signals at these types of locations. In a poor environment, radio signals from some sources (e.g. WiFi access points, Femtocells) may sometimes be available, but there may be insufficient such sources to obtain location accurately (e.g. via trilateration). Alternatively, there may be some radio sources but the locations of the radio sources may not be known (e.g. due to lack of a site survey or lack of site measurements), or the locations of the radio sources may be known but may be unavailable to the user device or any location server in communication with the user device. Thus, not every indoor or underground location may constitute a poor positioning environment (e.g. in the case that radio signals can be detected at the location from multiple radio sources having locations that are both known and available). However, there may still be many indoor and/or underground locations for which location cannot be supported and that are thus poor positioning environments.
When a user device enters a poor positioning environment, it may still have an accurate estimate of its location that was obtained using, for example, standalone GNSS, A-GNSS, AFLT, OTDOA, E-CID, WiFi, or the like, while it was still outside of the poor environment. Alternatively, the user device may obtain its location via near-field communication (NFC) or Bluetooth (BT) interaction with some fixed device, such as a subway system billing machine, whose location is known and has been configured. Since NFC and BT communication often occur over very short distances (e.g. a few centimeters for NFC), the known location of the fixed device when transmitted to a user device may become a highly accurate location for the user device. After losing reception of reliable positioning signals, the user device may be able to maintain its location in the poor positioning environment for a temporary period of time (e.g. 10 minutes) using inertial navigation based on sensor measurements internal to the user device. However, the accuracy of the user device location will typically degrade as small measurement errors from internal sensors accumulate over time. Eventually, the user device location may become too inaccurate to support many applications, for example, the provision of navigation directions to the user or the provision to the user of the location of nearby places (e.g. restaurant, ticket kiosk, exit door, etc.).
To address this issue, the user device can broadcast its current location to other user devices using direct peer-to-peer radio communications, such as LTE-Direct (LTE-D), WiFi-Direct (WiFi-D), and/or the like. The other user devices that receive the location broadcasts can compute a round trip time (RTT) to the broadcasting user device. The RTT may be a significant parameter in deciding whether another user device is in proximity or not and can be measured via signal timing or from signal strength and signal quality. The receiving devices can then update their own locations using the location broadcasts and RTTs from two or more other user devices. Alternatively, the location broadcast and RTT for just one broadcasting device may be enough to update another user device's location when the transmission distance is known to be small due, for example, to receipt of a strong signal or measurement of a small RTT.
In this way, user devices whose own location estimates have degraded due to being inside a poor positioning environment for a long period of time can update their locations using location broadcasts from user devices that have recently entered the enclosed structure and that thus typically have more accurate location estimates. User devices can maintain an uncertainty factor (i.e. probable error) in their own location estimates and include this with the locations they broadcast. This can allow user devices to selectively use only the more accurate locations of other user devices, such as those that have most recently entered the poor environment. In a subway system, for example, user devices may travel long distances from one station to another during which time their own internal location may degrade significantly. However, these devices may be able to refresh their locations from user devices that have just entered the system, e.g. devices associated with users who have just boarded a train.
Maintenance of accurate locations in this way can also be used to help crowd source the locations of, for example, local wireless network access points and/or NFC and BT devices inside the poor positioning environment. For example, user devices may record the identity (e.g. an IEEE Media Access Control (MAC) address in the case of a WiFi access point) of each access point (or BT or NFC device) detected while in the poor location environment together with the current user device's estimate of its own location and location uncertainty at or during the time the access point was detected. The user device may also make and record signal measurements associated with the detected access point, such as measurements of radio signal strength from the access point and/or RTT. At some later time, the user device may upload the stored data for all access points detected while in the poor environment to a server, such as location server 170 in
To detect and correct location errors (e.g. location errors relating to user devices and/or fixed access points), user devices can compare location information they receive from multiple other devices and filter out locations that are inconsistent with those from most other devices. This can be done on an ongoing basis. In one example, a user device that broadcasts an erroneous location due, for example, to entering a poor positioning environment with an erroneous location, or acquiring an erroneous location from some other user devices while in the poor positioning environment, may be prevented from impairing the location estimates of another user device if the other user device receives other location estimates from many other user devices and ignores the location estimate from the user device with the erroneous location estimate due to its inconsistency with the location estimates from the many other devices. In another example, an error in the configured location of a given NFC or BT device may temporarily induce location errors in many other user devices (e.g. user devices that receive and make use of the configured erroneous location immediately prior to entering the poor positioning environment) and thereby infect such user devices with erroneous locations. However, such an erroneous location may be detected and removed later when any such infected user device comes into contact with user devices whose locations were correctly provided earlier from other NFC or BT devices or from other reliable position method sources such as A-GNSS, AFLT or OTDOA. Provided the number of infected user devices is much smaller than the total number of user devices in the poor positioning environment, the infected devices may discover the inconsistency between their own erroneous location estimates and the correct location estimates obtained via location broadcast from the much larger number of uninfected user devices. Further, by crowd sourcing locations, NFC or BT devices (or local wireless network access points, for example) that transfer erroneous locations to user devices may be identified and user devices may be instructed (e.g. by a server such as location server 170) to ignore locations from these transmitters.
As an example of location error detection, each user device may maintain a record of the identity of any NFC, BT, or other device from which it obtained a location estimate and may also record whether this location estimate (or a location estimate derived from such a location estimate using inertial sensors) was subsequently found to be inconsistent with either the location estimates of many other user devices or a location estimate obtained by the user device when it next enters a good positioning environment. The user device, or any server to which the location record is later uploaded by the user device, may then determine the NFC, BT, or other device that is in error. Erroneous transmitters may thus be identified by maintaining a history of location updating, detecting when a location is significantly in error (e.g. when a discrepancy occurs with other devices) and backtracking the error to its original source.
In some aspects, user devices may not have to determine which NFC or BT device (or local wireless network access point, for example) is in error, but may simply provide the information (location discrepancy and location updating history) to a server, such as location server 170, which may isolate the error by statistical means using data received from many user devices. For example, infected user devices may transfer an erroneous location to other user devices before discovering their locations were erroneous and the other user devices may transfer their obtained erroneous locations to still further user devices. In some cases, inconsistency with a correct location may not be discovered until a user device reenters a good positioning environment. But a user device may maintain a record of its location history including (i) the determination of a new location using location estimates broadcast from fixed NFC, BT, and/or WiFi devices, for example, and from other mobile user devices, (ii) the detection of a discrepancy in a current location estimate with that obtained from either the received locations of many other user devices or a reliable source of location, such as standalone GNSS, A-GNSS, or OTDOA, and optionally, (iii) the times at which location or a location discrepancy is determined. The user device may also record the value of any newly determined location and its uncertainty together with the value of the previous location and uncertainty for the user device that are being replaced. A user device may then provide such a detailed location history to a central server (e.g. location server 170). The central server may then trace back the location history of each infected user device that has detected a location discrepancy to the source of location prior to entry to the poor positioning environment. Sources of location that are fixed NFC, BT, or WiFi devices, for example, may be considered as candidates for an initial erroneous location. The server may also trace back the location histories of uninfected user devices for which no location discrepancy was detected. Location sources that lead to many infected user devices and few or no uninfected user devices would be prime candidates for erroneous location. Such sources may then be investigated (e.g. via manually locating them or locating them automatically using crowd sourcing) and, if needed, reconfigured with a correct location.
In some aspects, a central server may only trace back the location history of a user device when a location discrepancy is detected the first time the user device updates its location after entering the poor environment using locations received from other devices or using existing position methods if the device has reentered a good environment. This may avoid wrongly attributing an erroneous location to a source of location in a good environment when a user device starts out with a good location estimate in a poor environment and is subsequently infected with an erroneous location from other infected user devices that is not initially detected by the user device due to excessive degradation of the user device's initial location in the poor environment.
The poor environment 540 may be an indoor or underground environment, such as a subway system, in which UEs, such as UEs 542, 544, and 546, cannot reliably receive signals from a satellite, cellular, or local wireless network positioning system, and thus cannot use such a system to determine their locations. The UEs 542, 544, and 546 can, however, communicate with each other via direct peer-to-peer radio communications, such as LTE-D, WiFi-D, and/or the like, as indicated by the bidirectional arrows in
In the example of
Upon entering the poor environment 540, the UE 550 begins tracking its location using inertial navigation. The UE 550 also begins broadcasting its location to other UEs using direct peer-to-peer radio communications. The UE 550 can also broadcast a level of uncertainty, or probable error, in its location. The longer the UE 550 determines its location based on inertial navigation, the higher the uncertainty level of its location. The further the UE 550 travels in the poor environment 540, the higher the uncertainty level of its location may become due to the accumulation of location change errors from inertial sensor measurements. UEs that receive location information (location and uncertainty level) from several other UEs can use this information to update their own position, as discussed with reference to
In the example of
In some aspects, a UE may broadcast its location and possibly its location uncertainty and other information (e.g. identification of services in which the UE wishes to engage) in order to discover other UEs that are nearby and that have a common interest in supporting services that are related to the UEs being near to one another. For example, when it is possible to maintain accurate location (e.g. the UE is not in a poor positioning environment), a UE A receiving such a broadcast from another UE B may determine if the other UE B is nearby by comparing the location broadcast by the other UE B with the known location of UE A. If UEs A and B are near each other, then one or more applications in one or both UEs that support services related to the UEs being nearby may be informed. The services that are being supported by these applications may be referred to as “proximity services” and may include services that notify a user when friends, relatives or co-workers are nearby or notify a user when the user is near to some place of interest (e.g. a particular shop, an information kiosk, a theatre, a gas station, etc.). In these aspects, the primary reason for a UE to broadcast its location and location uncertainty may be to support such proximity services (e.g. if the broadcast of location has been standardized by such organizations as 3GPP and 3GPP2 to support this). The ability to also support accurate location in a poor positioning environment may then become an additional benefit that requires only limited implementation support in a user device additional to that which is required anyway to broadcast location to and receive location from other UEs to support proximity services.
At 620, the UE receives locations and corresponding uncertainty levels from one or more other UEs (or devices) via direct peer-to-peer radio communications. At 625, the UE determines whether or not its uncertainty level is greater than the uncertainty levels of any of the one or more other devices. If the UE's uncertainty level is less than or equal to the uncertainty levels of each of the other devices, then the flow returns to 605. If, however, the UE's uncertainty level is greater than the uncertainty level of at least one other UE by some threshold (which in some aspects may be zero), then at 630, the UE determines the distance(s) to the UE(s) with lower uncertainty levels. The UE can determine the distance to another UE by calculating the RTT to the other UE. The RTT can be measured via signal timing or from signal strength and signal quality. For example, the RTT may be measured by sending a signal or message from a device A to another device B and receiving back a response that includes the internal delay in the device B in sending back the response. The RTT would then be given by the difference between the transmission and reception times at the device A less the internal response delay at device B. The RTT multiplied by the speed of radio signals (typically the speed of light) and divided by two provides the distance between the device A and device B.
At 635, the UE determines its location and location uncertainty based on the received locations, received location uncertainties, and determined distances using, as an example, some form of trilateration or multilateration. In an aspect, the UE may ignore the determined distances if they are small (e.g. less than some threshold) and/or cannot be determined. In this aspect, the UE may determine its location based on just the received locations from the other devices by, for example, averaging the locations or location coordinates of the other devices or by using a weighted average of the other locations or location coordinates (e.g. where the weighting factors for the locations or location coordinates are proportional to the received signal strength for the associated devices). In this aspect, when the UE receives just one location from one other device and the RTT or distance is determined to be small (e.g. is determined to be less than some threshold) or is assumed to be small (e.g. based on a signal strength from the other device exceeding some threshold), the UE may set its new location to be the same as the location received from the other device and may set its new location uncertainty to be greater than the location uncertainty received from the other device to take account of the error in neglecting the RTT.
At 640, the UE determines whether or not the new location is more accurate than the previous location. If it is not, then the flow returns to 605. If it is, however, then at 645, the UE stores the new location in its internal memory, such as memory 212 or database 214. The flow then returns to 605.
At 605, if the UE is not in a poor positioning environment, then at 650, the UE sends any history of received locations and determined locations that the UE may have stored while previously in a poor positioning environment, to a location server, such as location server 170. The server can use this information to track the location of the UE and to identify and correct errors in the locations of any fixed devices, such as NFC or BT transmitters. The action at 605 may be skipped if the UE has no location history from a poor positioning environment that was not yet sent to a location server. At 655, since the UE is not in a poor environment, it can now determine and maintain its location in the good environment using a satellite, cellular, or local wireless network positioning system. The flow returns to 605 to determine whether or not the UE has entered another poor environment.
Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
While the foregoing disclosure shows illustrative aspects of the disclosure, it should be noted that various changes and modifications could be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.
