BACKGROUND

[0001] Embodiments of the present disclosure relate to apparatus and method for wireless communication.

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. In wireless local area network (WLAN) communication (e.g., such as Wi-Fi) and in cellular communication (e.g., such as the 4th-generation (4G) Long Term Evolution (LTE) and the 5th-generation (5G) New Radio (NR)), the Institute of Electrical and Electronics Engineers (IEEE) and the 3rd Generation Partnership Project (3 GPP) define various operations for global navigation satellite system (GNSS) navigation.

SUMMARY

[0003] According to one aspect of the present disclosure, a method of wireless communication of a first user equipment (UE) is provided. The method may include identifying, by at least one processor, whether the first UE is located in an attenuated GNSS signal environment at a first time. The method may include, in response to determining that the first UE is located in the attenuated GNSS signal environment at the first time, implementing, by the at least one processor, a short GNSS signal acquisition-search mode for an extended duration until a position is identified after the first UE exits the attenuated GNSS signal environment. The method may include, in response to determining that the first UE is not located in the attenuated GNSS signal environment at the first time, implementing, by the at least one processor, the short GNSS signal acquisition-search mode for a non-extended duration followed by a long GNSS signal acquisitionsearch mode.

[0004] According to another aspect of the present disclosure, an apparatus for wireless communication of a first UE is provided. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform identifying whether the first UE is located in an attenuated GNSS signal environment at a first time. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform, in response to determining that the first UE is located in the attenuated GNSS signal environment at the first time, implementing a short GNSS signal acquisition- search mode for an extended duration until a position is identified after the first UE exits the attenuated GNSS signal environment. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform, in response to determining that the first UE is not located in the attenuated GNSS signal environment at the first time, implementing the short GNSS signal acquisition-search mode for a non-extended duration followed by a long GNSS signal acquisition- search mode.

[0005] According to yet another aspect of the present disclosure, a non-transitory computer-readable medium storing instructions for a first UE is provided. The non-transitory computer-readable medium may store instructions, which when executed by at least one processor, cause the at least one processor to perform identifying whether the first UE is located in an attenuated GNSS signal environment at a first time. The non-transitory computer-readable medium may store instructions, which when executed by at least one processor, cause the at least one processor to perform, in response to determining that the first UE is located in the attenuated GNSS signal environment at the first time, implementing a short GNSS signal acquisition- search mode for an extended duration until a position is identified after the first UE exits the attenuated GNSS signal environment. The non-transitory computer-readable medium may store instructions, which when executed by at least one processor, cause the at least one processor to perform, in response to determining that the first UE is not located in the attenuated GNSS signal environment at the first time, implementing the short GNSS signal acquisition- search mode for a non-extended duration followed by a long GNSS signal acquisition-search mode.

[0006] These illustrative embodiments are mentioned not to limit or define the present disclosure, but to provide examples to aid understanding thereof. Additional embodiments are discussed in the Detailed Description, and further description is provided there.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable a person skilled in the pertinent art to make and use the present disclosure. [0008] FIG. 1 illustrates an example GNSS signal -acquisition search technique.

[0009] FIG. 2 illustrates an exemplary wireless network, according to some embodiments of the present disclosure.

[0010] FIG. 3 illustrates a block diagram of an exemplary node, according to some embodiments of the present disclosure.

[0011] FIG. 4 illustrates a block diagram of an apparatus including a GNSS receiver, a wireless network interface, and a host chip, according to some embodiments of the present disclosure.

[0012] FIG. 5 illustrates a diagram of an exemplary technique for setting an attenuated GNSS-signal environment indicator, according to some embodiments of the present disclosure.

[0013] FIG. 6 illustrates a diagram of an exemplary GNSS signal-acquisition technique, according to some embodiments of the present disclosure.

[0014] FIG. 7 illustrates a flowchart of a method for wireless communication, according to some embodiments of the present disclosure.

[0015] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

DETAILED DESCRIPTION

[0016] Although specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the pertinent art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present disclosure. It will be apparent to a person skilled in the pertinent art that the present disclosure can also be employed in a variety of other applications.

[0017] It is noted that references in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” “some embodiments,” “certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of a person skilled in the pertinent art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. [0018] In general, terminology may be understood at least in part from usage in context. For example, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a,” “an,” or “the,” again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

[0019] Various aspects of wireless communication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether such elements are implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0020] The techniques described herein may be used for various wireless communication networks, such as code division multiple access (CDMA) system, time division multiple access (TDMA) system, frequency division multiple access (FDMA) system, orthogonal frequency division multiple access (OFDMA) system, single-carrier frequency division multiple access (SC- FDMA) system, wireless local area network (WLAN) system, a global navigation satellites system (GNSS), and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio access technology (RAT), such as Universal Terrestrial Radio Access (UTRA), evolved UTRA (E-UTRA), CDMA 2000, etc. A TDMA network may implement a RAT, such as the Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT, such as LTE or NR. A WLAN system may implement a RAT, such as Wi-Fi. The techniques described herein may be used for the wireless networks and RATs mentioned above, as well as other wireless networks and RATs.

[0021] GNSS is frequently used for positioning services in various applications, an example of which is vehicular navigation. To accurately determine its position, a UE is generally equipped with a GNSS receiver. The GNSS receiver uses the time difference between the time a signal is received versus when the signal was broadcast by a satellite vehicle (SV) to determine the GNSS receiver’s distance from the SV. A GNSS receiver that receives signals from four SVs can determine its position in three dimensions (3D). Three of the SVs are used to determine latitude, longitude, and height, while a fourth SV is set to synchronize the GNSS receiver’s internal clock. [0022] A GNSS receiver uses a signal search engine to acquire GNSS signals from the SVs and make position fixes. After activation, the GNSS receiver attempts to acquire multiple signals. For strong signals, the acquisition search mode can be short (e.g., such as tens of milliseconds) so that the time-to-first-fix (TTFF) is small. On the other hand, for weak signals, the acquisition search mode is longer (e.g., a couple of seconds) to provide good sensitivity. However, before the GNSS receiver succeeds or fails in acquiring a GNSS signal, it does not know whether the GNSS signal is strong or weak. Therefore, upon activation, the GNSS receiver may initially implement a short GNSS signal acquisition-search mode in an attempt to acquire strong GNSS signals. When GNSS signals are unable to be acquired using the short mode, the GNSS receiver may then implement a long GNSS signal acquisition-search mode in an attempt to acquire weak GNSS signals. However, this example search technique that switches from short mode to long mode suffers from certain challenges when the UE is initially located in an attenuated GNSS-signal environment (e.g., a very weak signal condition) and moves to strong signal condition. A good example is the situation in which a car starts from a parking garage where the GNSS signals are completely attenuated.

[0023] The timing diagram 100 depicted in FIG. 1 illustrates such a scenario. For instance, referring to FIG. 1, when the GNSS receiver is activated in the car’s navigation application or from a smartphone with a navigation application at time tO, the initial short GNSS signal acquisitionsearch mode will fail since the GNSS signals are initially blocked within the garage. The GNSS receiver then implements a long GNSS signal -acquisition mode to search for weak signals. In the scenario depicted in FIG. 1, because the car is still inside the parking garage (e.g., an attenuated GNSS-signal environment), the GNSS receiver is still unable to acquire any GNSS signal. Due to its initial location within the attenuated GNSS-signal environment (e.g., the garage), the GNSS receiver thinks the GNSS signals are weak and repeats the long mode again and again. At time tl, the car exits the parking garage and runs in open sky. At time tl, the driver immediately expects instruction on directions (e.g., left or right turn) for its destination. However, because the GNSS receiver is still in the very slow long mode, a common problem is that the GNSS receiver often takes a few seconds before the first driving instruction is provided. This degrades the user experience. The reason for this undesirable delay is that even though the GNSS signals are strong outside of the garage, the GNSS receiver is still performing the long search, and, hence, takes a longer time to acquire signals, calculate the first position fix, and provide directions, as compared to if it implemented the short mode upon exiting the garage.

[0024] Thus, there exists an unmet need for an adaptive GNSS search mode that avoids using the long GNSS signal-acquisition mode when exiting an attenuated GNSS-signal environment.

[0025] To overcome these and other challenges, the present disclosure provides an exemplary GNSS signal-acquisition technique, which enables the GNSS receiver to identify when it is temporarily located in an attenuated GNSS-signal environment upon activation. For instance, the GNSS receiver disclosed herein may implement the short GNSS signal-acquisition mode for an extended duration until it is no longer in the attenuated GNSS-signal environment and GNSS signals are acquired. One such example is when a user starts her/his car in a parking garage and activates a navigation application. Here, the GNSS receiver associated with the navigation application will implement the short GNSS signal -acquisition mode until the car exits the garage and is able to acquire strong GNSS signals.

[0026] In some embodiments, the GNSS receiver may identify an attenuated GNSS-signal environment when the GNSS signal strength drops abrupted for a predetermined amount of time. When this happens, the GNSS receiver may cause the display of an icon on a display device to ask the user whether it is located in a garage before the navigation application is powered off. If the user indicates that the GNSS receiver is located in a garage, the GNSS receiver may store a first indication in a non-volatile memory. A second indication may be stored in the non-volatile memory if the user indicates that the GNSS receiver is not located in a garage. Once powered on at a later time, the GNSS receiver may retrieve the indication from the non-volatile memory to determine whether it is initially and temporarily located in an attenuated GNSS-signal environment. In response to determining that it is located in the attenuated GNSS-signal environment, the exemplary GNSS receiver may implement the short GNSS signal-acquisition mode for an extended duration until the car exists the garage and GNSS signals are quickly acquired. In some embodiments, the exemplary GNSS receiver may identify that it is located in an attenuated GNSS-signal environment when certain GNSS signal conditions are met. When this happens, the exemplary GNSS receiver may store its own indication (e.g., a flag set to ‘garage’) in non-volatile memory. This indication may also be used to determine whether it is located in the attenuated GNSS-signal environment when it is activated once again at a later time when the user returns to her/his vehicle. In this way, the exemplary GNSS receiver of the present disclosure may provide the user with directions as they exit the garage in a timelier manner, as compared to other GNSS signal-acquisition techniques. Additional details of the exemplary GNSS receiver and its GNSS signal-acquisition procedure are provided below in connection with FIGs. 2-7.

[0027] FIG. 2 shows a simplified architecture of a wireless communication system 200 in accordance with certain embodiments presented herein. System 200 may include non-access point (AP) stations (STAs) such as UEs 220-1 through 220-w (collectively referred to as UEs 220), and AP STAs such as APs 240-1 through 240-4 (collectively referred to as APs 240), which may communicate over a wireless communication network 230. Examples of UEs 220 may include, e.g., smartphones, vehicles, wearable devices, laptops, or any other device that can provide a navigation function to a user. In some embodiments, wireless communication network 230 may take the form of and/or may include one or more wireless local area networks (WLANs) or the internet. In some embodiments, UEs 220 and/or APs 240 may communicate with server 250 via wireless communication network 230. While system 200 illustrates some UEs 220 and APs 240, the number of UEs 220 and APs 240 in a wireless communication network (e.g., a WLAN) may be varied in accordance with various system parameters. In general, system 200 may include a smaller or larger number of UEs 220 and/or APs 240.

[0028] In some embodiments, as outlined above, UE 220 may include a GNSS receiver configured to receive, measure and decode signals from one or more satellite vehicles (SVs) 280- 1 through 280-4 and thereby obtain a position fix, an accurate absolute time reference (such as global positioning system (GPS) time, Coordinated Universal Time (UTC) or a time for another GNSS which may be accurate to 50 nanoseconds (ns) or better in some embodiments) and a timing reference uncertainty. The position information may be used for navigation, for example.

[0029] Still referring to FIG. 2, in some embodiments, any suitable node of wireless communication system 200, such as UE 220 (e.g., a vehicle, a smartphone, navigation device, etc.), may include a GNSS receiver. UE 220 may include an exemplary GNSS receiver, such as GNSS receiver 402 in FIG. 4, may be configured to perform the exemplary GNSS signal-acquisition technique to receive GNSS signals from one or more SVs 280-1, 280-2, 280-3, 280-4, etc. using an extended short GNSS signal -acquisition mode when UE 220 is initially and temporarily located in an attenuated GNSS-signal environment upon activation of GNSS receiver 402. Additional details of the exemplary GNSS receiver and its exemplary GNSS signal-acquisition technique are provided below in connection with FIGs. 4-7.

[0030] Each element in FIG. 2 may be considered a node of wireless communication system 200. More detail regarding the possible implementation of a node is provided by way of example in the description of a node 300 in FIG. 3. Node 300 may be configured as UE 220, AP 240, or server 250 in FIG. 2. As shown in FIG. 3, node 300 may include a processor 302, a memory 304, and a transceiver 306. These components are shown as connected to one another by a bus, but other connection types are also permitted. When node 300 is UE 220, additional components may also be included, such as a user interface (UI), sensors, and the like. Similarly, node 300 may be implemented as a blade in a server system when node 300 is configured as server 250. Other implementations are also possible.

[0031] Transceiver 306 may include any suitable device for sending and/or receiving data. Node 300 may include one or more transceivers, although only one transceiver 306 is shown for simplicity of illustration. An antenna 308 is shown as a possible communication mechanism for node 300. Multiple antennas and/or arrays of antennas may be utilized for receiving multiple spatially multiplex data streams. Additionally, examples of node 300 may communicate using wired techniques rather than (or in addition to) wireless techniques. For example, AP 240 may communicate wirelessly to UE 220 and may communicate by a wired connection (for example, by optical or coaxial cable) to server 250. Other communication hardware, such as a network interface card (NIC), may be included as well.

[0032] As shown in FIG. 3, node 300 may include processor 302. Although only one processor is shown, it is understood that multiple processors can be included. Processor 302 may include microprocessors, microcontroller units (MCUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout the present disclosure. Processor 302 may be a hardware device having one or more processing cores. Processor 302 may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software can include computer instructions written in an interpreted language, a compiled language, or machine code. Other techniques for instructing hardware are also permitted under the broad category of software. [0033] As shown in FIG. 3, node 300 may also include memory 304. Although only one memory is shown, it is understood that multiple memories can be included. Memory 304 can broadly include both memory and storage. For example, memory 304 may include random-access memory (RAM), read-only memory (ROM), static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FRAM), electrically erasable programmable ROM (EEPROM), compact disc read only memory (CD-ROM) or other optical disk storage, hard disk drive (HDD), such as magnetic disk storage or other magnetic storage devices, Flash drive, solid-state drive (SSD), or any other medium that can be used to carry or store desired program code in the form of instructions that can be accessed and executed by processor 302. Broadly, memory 304 may be embodied by any computer-readable medium, such as a non-transitory computer-readable medium.

[0034] Processor 302, memory 304, and transceiver 306 may be implemented in various forms in node 300 for performing wireless communication functions. In some embodiments, processor 302, memory 304, and transceiver 306 of node 300 are implemented (e.g., integrated) on at least one system-on-chip (SoC) or system-in-package (SiP). In one example, processor 302 and memory 304 may be integrated on an application processor (AP) SoC (sometimes known as a “host,” referred to herein as a “host chip”) that handles application processing in an operating system (OS) environment, including generating raw data to be transmitted. In another example, processor 302 and memory 304 may be integrated on a baseband processor (BP) SoC (sometimes known as a “modem,” referred to herein as a “radio”) that converts the raw data, e.g., from the host chip, to signals that can be used to modulate the carrier frequency for transmission, and vice versa, which can run a real-time operating system (RTOS). In still another example, processor 302 and transceiver 306 (and memory 304 in some cases) may be integrated on an RF SoC (sometimes known as a “transceiver,” referred to herein as a “wireless network interface”) that transmits and receives RF signals with antenna 308. It is understood that in some examples, some or all of the host chip, radio, and wireless network interface may be integrated as a single SoC. For example, a radio and a wireless network interface may be integrated into a single SoC that manages all the radio functions for GNSS communication, WLAN communication, wireless personal area network (WPAN) communication, and/or cellular communication.

[0035] FIG. 4 illustrates a block diagram of an apparatus 400 including a GNSS receiver 402, a wireless network interface 404, and a host chip 406, according to some embodiments of the present disclosure. FIG. 5 illustrates a diagram of an exemplary technique 500 for setting an attenuated GNSS-signal environment indicator, according to some embodiments of the present disclosure. FIG. 6 illustrates a diagram of an exemplary GNSS signal-acquisition technique 600, according to some embodiments of the present disclosure. FIGs. 4-6 will be described together.

[0036] Referring to FIG. 4, apparatus 400 may be implemented as UE 220 of wireless communication system 200 in FIG. 2. In some embodiments, GNSS receiver 402 is implemented by processor 302 and memory 304, and wireless network interface 404 is implemented by processor 302, memory 304, and transceiver 306, as described above with respect to FIG. 3. When used for positioning determination within a GNSS communication system, GNSS receiver 402 may be implemented as a GNSS receiver radio.

[0037] Besides the on-chip memory 418 (also known as “internal memory,” e.g., registers, buffers, or caches) on GNSS receiver 402, wireless network interface 404, or host chip 406, apparatus 400 may further include an external memory 408 (e.g., the system memory or main memory) that can be shared by GNSS receiver 402, wireless network interface 404, or host chip 406 through the system/main bus. On-chip memory 418 and/or external memory 408 may include a non-volatile memory. Although GNSS receiver 402 is illustrated as a standalone SoC in FIG. 4, it is understood that in one example, GNSS receiver 402 and wireless network interface 404 may be integrated as one SoC or SiP; in another example, GNSS receiver 402 and host chip 406 may be integrated as one SoC or SiP; in still another example, GNSS receiver 402, wireless network interface 404, and host chip 406 may be integrated as one SoC or SiP, as described above.

[0038] In the uplink, host chip 406 may generate raw data and send it to GNSS receiver 402 for encoding, modulation, and mapping. Interface 414 of GNSS receiver 402 may receive the data from host chip 406. GNSS receiver 402 may also access the raw data generated by host chip 406 and stored in external memory 408, for example, using the direct memory access (DMA). GNSS receiver 402 may first encode (e.g., by source coding and/or channel coding) the raw data and modulate the coded data using any suitable modulation techniques, such as multi-phase shift keying (MPSK) modulation or quadrature amplitude modulation (QAM). GNSS receiver 402 may perform any other function, such as symbol or layer mapping, to convert the raw data into a signal that can be used to modulate the carrier frequency for transmission. In the uplink, GNSS receiver 402 may send the modulated signal to wireless network interface 404 via interface 414. Wireless network interface 404, through a transmitter (TX) 450, may convert the modulated signal in the digital form into analog signals, i.e., RF signals, and perform any suitable front-end RF functions, such as filtering, digital pre-distortion, up-conversion, or sample-rate conversion. Antenna array 410 may transmit the RF signals provided by TX 450 of wireless network interface 404. In some embodiments, GNSS receiver 402 may be configured to perform receive functions only. Here, the transmission function may be implemented via a wireless network interface, e.g., such as a Wi-Fi, Bluetooth, or cellular communication component, that is attached to GNSS receiver 402.

[0039] In the downlink, antenna array 410 may receive GNSS signals from one or more SVs, for example. The GNSS signals may include one or more line-of-sight (LOS) signals and/or non-LOS (NLOS) signals. The GNSS signals may be passed to a receiver (RX) 440 of wireless network interface 404. Wireless network interface 404 may perform any suitable front-end RF functions, such as filtering, IQ imbalance compensation, down-paging conversion, or sample-rate conversion, and convert the RF signals (e.g., transmission) into low-frequency digital signals (baseband signals) that can be processed by GNSS receiver 402.

[0040] As seen in FIG. 4, GNSS receiver 402 may include a signal acquisition component 420, garage identification component 422, and navigation component 424. Each of signal acquisition component 420, garage identification component 422, and navigation component 424 may include shared or dedicated hardware, firmware, software, or any combination thereof to implement the operations described below.

[0041] To solve the above-described “out of garage” problem from which other GNSS signal -acquisition techniques suffer, GNSS receiver 402 includes garage identification component 422. In some embodiments, when apparatus 400 is being turned off, garage identification component 422 may cause a user interface (UI) to display an icon (e.g., such as check box) so that the user can indicate apparatus 400 is inside a garage or another attenuated GNSS-signal environment. The user indication may be stored in non-volatile memory, e.g., such as on-chip memory 418 and/or external memory 408, so that when the apparatus is powered on again, garage identification component 422 may retrieve the indicate to determine whether or not to implement the exemplary short GNSS signal -acquisition mode for an extended duration.

[0042] In some other embodiments, garage identification component 422 may identify whether apparatus 400 has entered a garage based on a drop in GNSS signal strength directly proceeding to deactivation.

[0043] When apparatus 400 is a car with a built-in GNSS receiver 402, garage identification component 422 may record the measured GNSS signals strength every T seconds (for example, T=2). The garage indicator will be set ‘True’ and stored into non-volatile memory, such as on-chip memory 418 and/or external memory 408 when the car is being turned off if: (a) the strength of all or most of GNSS signals drops significantly; and (b) the car is turned off when strength of the GNSS signal remains below a threshold level. When the car and its GNSS receiver 402 are next turned on, garage identification component 422 may read/retrieve the garage indicator from the non-volatile memory. If the indicator is set to ‘True,’ signal acquisition component 420 will implement the short GNSS signal-acquisition mode with an extended duration without switching to long GNSS signal-acquisition mode. This may reduce the TTFF when the car leaves the garage significantly, thereby improving the user experience. For example, as depicted in FIG. 6, the TTFF may be reduced from 3.8s to 0.3s using the exemplary short GNSS signal -acquisition mode with the extended duration.

[0044] By way of example, referring to FIG. 5, garage identification component 422 may measure the signal -to-noise ratio (SNR.) and/or the signal -to-interference-plus-noise ratio (SINR) the GNSS signals received by signal acquisition component 420 to identify when there is a significant drop in signal strength that never recovers before the navigation application is turned off. When the drop in signal strength meets certain attenuated-signal criteria, garage identification component 422 may identify that apparatus 400 has entered an attenuated GNSS-signal environment, e.g., such as a garage.

[0045] To identify whether the strength of all or most of the GNSS signals meets the attenuated-signal criteria, garage identification component 422 may (a) calculate the average C/No of the K strongest GNSS signals at predetermined intervals (e.g., each second), where the average may be denoted mean_CNo(t) at time t. When the mean_CNo(t) drops by more than a threshold (X dB), garage identification component 422 may identify that apparatus 400 has entered a garage, tunnel, or another type of attenuated GNSS-signal environment. For example, when garage identification component 422 determines mean_CNo(t-l) - mean_CNo(t) > X dB, this may indicate apparatus 400 has entered an attenuated GNSS-signal environment. By way of example and not limitation, K=5 and X = 8dB.

[0046] To ensure the garage case is not flagged when apparatus 400 is in a tunnel, garage identification component 422 may (b) determine whether the average C/No of the K strongest GNSS signals remains below a threshold value at or near the time at which apparatus 400 is turned off. For instance, when mean_CNo(t) < Y dBHz, garage identification component 422 may determine apparatus 400 is in a garage and not a tunnel. By way of example and not limitation, Y=20dBHz.

[0047] Referring again to FIG. 4, when apparatus 400 is a smartphone with a built-in GNSS receiver 402, the above-described technique for setting the garage indicator based on GNSS-signal strength may also be performed. In some embodiments, once the garage indicator is set, the smartphone may pass the garage indicator setting via Bluetooth (or another type of communication link) to the car, where it is stored in the car’s non-volatile memory. When the user returns to the car and starts it, the car will transmit the garage indicator to the smartphone via the communication link. After the smartphone knows the garage indicator, signal acquisition component 420 will use the corresponding search mode accordingly, for example, keep using short mode if garage indicator is set to ‘True.’ In some other embodiments, the smartphone may store the garage indicator along with a car identification ID (e.g., Bluetooth ID). Then, the next time the smartphone enters a car, when the car is turned on, the smartphone can check the stored car ID with that of the vehicle in which it is located. If the garage indicator is set to ‘True’ and the car ID of the car in which the smartphone is now located matches the stored ID, the smartphone may determine that GNSS receiver 402 is located in a garage and for signal acquisition component 420 to perform the exemplary short GNSS signal -acquisition mode with the extended duration.

[0048] Using any of the above embodiments, when the car exits the garage, navigation component 424 may identify the location and provide navigation directions in less time than if a short GNSS signal-acquisition mode followed by the long GNSS signal-acquisition mode (described above in connection with FIG. 1) were used. On the other hand, when the garage indicator is set to ‘Not True,’ when the car or the navigation application on the smartphone is next activated, signal acquisition component 420 may implement the short GNSS signal-acquisition mode followed by the long GNSS signal -acquisition mode, as described above in connection with FIG. 1.

[0049] In some other embodiments in which apparatus 400 is a smartphone, if the garage indicator is set to ‘True,’ this may imply that the smartphone may be located inside a building for a certain duration. In this case, signal acquisition component 420 may perform the long GNSS signal -acquisition mode without first performing the short GNSS signal -acquisition mode since the strength of the GNSS signals within the building is mostly weak.

[0050] FIG. 7 illustrates a flowchart of an exemplary method 700 of wireless communication, according to embodiments of the disclosure. Exemplary method 700 may be performed by an apparatus, e.g., such as UE 220, node 300, apparatus 400, GNSS receiver 402, external memory 408, on-chip memory 418, signal acquisition component 420, garage identification component 422, and/or navigation component 424. Method 700 may include steps 702-706 as described below. It is to be appreciated that some of the steps may be optional, and some of the steps may be performed simultaneously, or in a different order than shown in FIG. 7. [0051] At 702, the apparatus may identify whether the car is located within an attenuated GNSS-signal environment. For example, referring to FIGs. 4 and 5, To solve the above-described “out of garage” problem from which other GNSS signal-acquisition techniques suffer, GNSS receiver 402 includes garage identification component 422. In some embodiments, when apparatus 400 is being turned off, garage identification component 422 may cause a user interface (UI) to display an icon (e.g., such as check box) so that the user can indicate apparatus 400 is inside a garage or another attenuated GNSS-signal environment. The user indication may be stored in nonvolatile memory, e.g., such as on-chip memory 418 and/or external memory 408, so that when the apparatus is powered on again, garage identification component 422 may retrieve the indicate to determine whether or not to implement the exemplary short GNSS signal-acquisition mode for an extended duration.

[0052] In some other embodiments, garage identification component 422 may identify whether apparatus 400 has entered a garage based on a drop in GNSS signal strength directly proceeding deactivation.

[0053] When apparatus 400 is a car with a built-in GNSS receiver 402, garage identification component 422 may record the measured GNSS signals strength every T seconds (for example, T=2). The garage indicator will be set ‘True’ and stored into non-volatile memory, such as on-chip memory 418 and/or external memory 408 when the car is being turned off if: (a) the strength of all or most of GNSS signals drops significantly; and (b) the car is turned off when the strength of the GNSS signal remains below a threshold level. By way of example, referring to FIG. 5, garage identification component 422 may measure the signal-to-noise ratio (SNR) and/or the signal-to-interference-plus-noise ratio (SINR) of the GNSS signals received by signal acquisition component 420 to identify when there is a significant drop in signal strength that never recovers before the navigation application is turned off. When the drop in signal strength meets certain attenuated-signal criteria, garage identification component 422 may identify that apparatus 400 has entered an attenuated GNSS-signal environment, e.g., such as a garage. To identify whether the strength of all or most of the GNSS signals meets the attenuated-signal criteria, garage identification component 422 may (a) calculate the average C/No of the K strongest GNSS signals at predetermined intervals (e.g., each second), where the average may be denoted mean_CNo(t) at time t. When the mean_CNo(t) drops by more than a threshold (X dB), garage identification component 422 may identify that apparatus 400 has entered a garage, tunnel, or another type of attenuated GNSS-signal environment. For example, when garage identification component 422 determines mean CNo(t-l) - mean_CNo(t) > X dB, this may indicate apparatus 400 has entered an attenuated GNSS-signal environment. By way of example and not limitation, K=5 and X = 8dB. To ensure the garage case is not flagged when apparatus 400 is in a tunnel, garage identification component 422 may (b) determine whether the average C/No of the K strongest GNSS signals remains below a threshold value at or near the time at which apparatus 400 is turned off. For instance, when mean_CNo(t) < Y dBHz, garage identification component 422 may determine apparatus 400 is in a garage and not a tunnel. By way of example and not limitation, Y=20dBHz.

[0054] In response to identifying that the car is located in the attenuated GNSS-signal environment (YES: at 702), the operations may move to 704. Otherwise, in response to determining that the car is not located in the attenuated GNSS-signal environment (NO: at 702), the operations may move to 706.

[0055] At 704, the apparatus may implement a short GNSS signal -acquisition mode for an extended duration. For example, referring to FIGs. 4 and 6, if the indicator is set to ‘True,’ signal acquisition component 420 will implement the short GNSS signal-acquisition mode with an extended duration without switching to long GNSS signal-acquisition mode. This may reduce the TTFF when the car leaves the garage significantly, thereby improving the user experience. For example, as depicted in FIG. 6, the TTFF may be reduced from 3.8s to 0.3s using the exemplary short GNSS signal -acquisition mode with the extended duration.

[0056] At 706, the apparatus may implement the short GNSS signal-acquisition mode followed by the long GNSS signal-acquisition mode. For example, referring to FIGs. 1 and 4, when the garage indicator is set to ‘Not True,’ when the car or the navigation application on the smartphone is next activated, signal acquisition component 420 may implement the short GNSS signal -acquisition mode followed by the long GNSS signal-acquisition mode, as described above in connection with FIG. 1.

[0057] In various aspects of the present disclosure, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as instructions or code on a non-transitory computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computing device, such as node 300 in FIG. 3. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD, such as magnetic disk storage or other magnetic storage devices, Flash drive, SSD, 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 processing system, such as a mobile device or a computer. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital video disc (DVD), and floppy disk 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. [0058] According to one aspect of the present disclosure, a method of wireless communication of a first UE is provided. The method may include identifying, by at least one processor, whether the first UE is located in an attenuated GNSS signal environment at a first time. The method may include, in response to determining that the first UE is located in the attenuated GNSS signal environment at the first time, implementing, by the at least one processor, a short GNSS signal acquisition- search mode for an extended duration until a position is identified after the first UE exits the attenuated GNSS signal environment. The method may include, in response to determining that the first UE is not located in the attenuated GNSS signal environment at the first time, implementing, by the at least one processor, the short GNSS signal acquisition-search mode for a non-extended duration followed by a long GNSS signal acquisition-search mode.

[0059] In some embodiments, the method may include displaying, by a user interface, an icon requesting information related to whether the first UE is located in the attenuated GNSS signal environment. In some embodiments, the icon may be displayed at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to receiving a first indication that the first UE is located in the attenuated GNSS signal environment at the first time based on a first interaction with the icon, identifying that the first UE is located in the attenuated GNSS signal environment at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to receiving a second indication that the first UE is not located in the attenuated GNSS signal environment at the first time based on a second interaction with the icon, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time.

[0060] In some embodiments, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remains at or below the threshold value when the first UE is turned off at a second time period before the first time, the method may include maintaining, by a memory, a first indication that the first UE is located in the attenuated GNSS signal environment. In some embodiments, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signals does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, the method may include maintaining, by the memory, a second indication that the first UE is not located in the attenuated GNSS signal environment. In some embodiments, the first indicator or the second indication may be maintained at a second time before the first time.

[0061] In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include retrieving, from the memory, the first indication or the second indication at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to the first indication being retrieved from the memory at the first time, identifying that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to the second indication being retrieved from the memory at the first time, identifying that the first UE is not located in the attenuated GNSS signal environment.

[0062] In some embodiments, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remains at or below the threshold value when the first UE is turned off at a second time period before the first time, the method may include sending, by a communication interface, the first indication that the first UE is located in the attenuated GNSS signal environment to a second UE at the second time. In some embodiments, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signals does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, the method may include sending, by the communication interface, the second indication that the first UE is located in the attenuated GNSS signal environment to the second UE at the second time.

[0063] In some embodiments, the method may include receiving, by the communication interface, the first indication or the second indication from the second UE at the first time when a GNSS receiver of the first UE is activated. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to the first indication being received from the second UE at the first time, identifying that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the method may include receiving, by the communication interface, the first indication or the second indication from the second UE at the first time when a GNSS receiver of the first UE is activated. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to the second indication being received from the second UE at the first time, identifying that the first UE is not located in the attenuated GNSS signal environment.

[0064] In some embodiments, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remains at or below the threshold value when the first UE is turned off at a second time period before the first time, the method may include maintaining, by the memory, an identification associated with a second UE along with the first indication. In some embodiments, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signals does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, the method may include maintaining, by the memory, the identification associated with the second UE along with the second indication.

[0065] In some embodiments, the method may include retrieving, from the memory, the first indication or the second indication and the identification associated with the second UE at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to retrieving the first indication and determining that the first UE is located within the second UE at the first time based on the identification, identifying that the first UE is located in the attenuated GNSS signal environment at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to retrieving the first indication and determining that the first UE is not located within the second UE at the first time based on the indication, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to retrieving the second indication and determining that the first UE is located within the second UE at the first time based on the indication, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time. In some embodiments, the identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time may include, in response to retrieving the second indication and determining that the first UE is not located within the second UE at the first time based on the indication, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time.

[0066] In some embodiments, in response to identifying that first indication that the first UE is located in the attenuated GNSS signal environment at the first time, the method may include implementing, by the at least one processor, the long GNSS signal acquisition-search mode during a second time immediately following the first time.

[0067] According to another aspect of the present disclosure, an apparatus for wireless communication of a first UE is provided. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform identifying whether the first UE is located in an attenuated GNSS signal environment at a first time. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform, in response to determining that the first UE is located in the attenuated GNSS signal environment at the first time, implementing a short GNSS signal acquisition- search mode for an extended duration until a position is identified after the first UE exits the attenuated GNSS signal environment. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform, in response to determining that the first UE is not located in the attenuated GNSS signal environment at the first time, implementing the short GNSS signal acquisition-search mode for a non-extended duration followed by a long GNSS signal acquisition- search mode.

[0068] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform causing a user interface to display an icon requesting information related to whether the first UE is located in the attenuated GNSS signal environment. In some embodiments, the icon may be displayed at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to receiving a first indication that the first UE is located in the attenuated GNSS signal environment at the first time based on a first interaction with the icon, identifying that the first UE is located in the attenuated GNSS signal environment at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to receiving a second indication that the first UE is not located in the attenuated GNSS signal environment at the first time based on a second interaction with the icon, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time.

[0069] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remain at or below the threshold value when the first UE is turned off at a second time period before the first time, causing a memory to maintain a first indication that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further causes the at least one processor to perform, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signal does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, causing the memory to maintain a second indication that the first UE is not located in the attenuated GNSS signal environment. In some embodiments, the first indicator or the second indication may be maintained at a second time before the first time.

[0070] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by retrieving, from the memory, the first indication or the second indication at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to the first indication being retrieved from the memory at the first time, identifying that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to the second indication being retrieved from the memory at the first time, identifying that the first UE is not located in the attenuated GNSS signal environment.

[0071] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remain at or below the threshold value when the first UE is turned off at a second time period before the first time, causing a communication interface to send the first indication that the first UE is located in the attenuated GNSS signal environment to a second UE at the second time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signal does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, causing the communication interface to send the second indication that the first UE is located in the attenuated GNSS signal environment to the second UE at the second time.

[0072] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform receiving, from the communication interface, the first indication or the second indication from the second UE at the first time when a GNSS receiver of the first UE is activated. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to the first indication being received from the second UE at the first time, identifying that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to the second indication being received from the second UE at the first time, identifying that the first UE is not located in the attenuated GNSS signal environment.

[0073] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remain at or below the threshold value when the first UE is turned off at a second time period before the first time, maintaining, by the memory, an identification associated with a second UE along with the first indication. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signal does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, maintaining, by the memory, the identification associated with the second UE along with the second indication. [0074] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform retrieving, from the memory, the first indication or the second indication and the identification associated with the second UE at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to retrieving the first indication and determining that the first UE is located within the second UE at the first time based on the identification, identifying that the first UE is located in the attenuated GNSS signal environment at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to retrieving the first indication and determining that the first UE is not located within the second UE at the first time based on the indication, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to retrieving the second indication and determining that the first UE is located within the second UE at the first time based on the indication, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to retrieving the second indication and determining that the first UE is not located within the second UE at the first time based on the indication, identifying that the first UE is not located in the attenuated GNSS signal environment at the first time.

[0075] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform in response to identifying that first indication that the first UE is located in the attenuated GNSS signal environment at the first time, implementing the long GNSS signal acquisition- search mode during a second time immediately following the first time.

[0076] According to yet another aspect of the present disclosure, a non-transitory computer-readable medium storing instructions for a first UE is provided. The non-transitory computer-readable medium may store instructions, which when executed by at least one processor, cause the at least one processor to perform identifying whether the first UE is located in an attenuated GNSS signal environment at a first time. The non-transitory computer-readable medium may store instructions, which when executed by at least one processor, cause the at least one processor to perform, in response to determining that the first UE is located in the attenuated GNSS signal environment at the first time, implementing a short GNSS signal acquisition- search mode for an extended duration until a position is identified after the first UE exits the attenuated GNSS signal environment. The non-transitory computer-readable medium may store instructions, which when executed by at least one processor, cause the at least one processor to perform, in response to determining that the first UE is not located in the attenuated GNSS signal environment at the first time, implementing the short GNSS signal acquisition- search mode for a non-extended duration followed by a long GNSS signal acquisition-search mode.

[0077] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that a strength of one or more GNSS signals drops below a threshold value and remain at or below the threshold value when the first UE is turned off at a second time period before the first time, causing a memory to maintain a first indication that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may further cause the at least one processor to perform, in response to determining that the strength of the one or more GNSS signals does not drop below the threshold value or that the strength of the one or more GNSS signal does not remain at or below the threshold value when the first UE is turned off at the second time period before the first time, causing the memory to maintain a second indication that the first UE is not located in the attenuated GNSS signal environment. In some embodiments, the first indicator or the second indication may be maintained at a second time before the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by retrieving, from the memory, the first indication or the second indication at the first time. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to the first indication being retrieved from the memory at the first time, identifying that the first UE is located in the attenuated GNSS signal environment. In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying, by at least one processor, whether the first UE is located in the attenuated GNSS signal environment at the first time by, in response to the second indication being retrieved from the memory at the first time, identifying that the first UE is not located in the attenuated GNSS signal environment.

[0078] The foregoing description of the specific embodiments will so reveal the general nature of the present disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

[0079] Embodiments of the present disclosure have been described above with the aid of functional obstacle blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional obstacle blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0080] The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0081] Various functional blocks, modules, and steps are disclosed above. The particular arrangements provided are illustrative and without limitation. Accordingly, the functional blocks, modules, and steps may be re-ordered or combined in different ways than in the examples provided above. Likewise, certain embodiments include only a subset of the functional blocks, modules, and steps, and any such subset is permitted.

[0082] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.