WO2018053787A1

WO2018053787A1 - Autonomous measurement report for carrier aggregation setup

Info

Publication number: WO2018053787A1
Application number: PCT/CN2016/099834
Authority: WO
Inventors: Tao Huang; Yanxia Wang; Bing Zhao
Original assignee: Apple Inc.
Priority date: 2016-09-23
Filing date: 2016-09-23
Publication date: 2018-03-29

Abstract

Techniques are disclosed for a wireless device to determine whether use of a secondary component carrier (SCC) would be preferred in a carrier aggregation scenario, and to take action to encourage or discourage the serving cell to add or release the SCC based on the determination. For example, in some embodiments, when the SCC is preferred, reports of positive performance of serving cells and/or a neighbor cell may be reported, while reports of negative performance of the serving cells may be delayed or suppressed. Inversely, in some embodiments, when the SCC is not preferred, reports of negative performance of the serving cells may be reported, while reports of positive performance of the serving cells and/or the neighbor cell may be delayed or suppressed. In some embodiments, the UE may determine whether the SCC is preferred based on volume of data traffic.

Description

Autonomous Measurement Report For Carrier Aggregation Setup

FIELD

The present application relates to wireless communications, and more particularly to signal measurement reporting when using carrier aggregation.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Additionally, there exist numerous different wireless communication technologies and standards. Some examples of wireless communication technologies include GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces) , LTE, LTE Advanced (LTE-A) , HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD) , IEEE 802.11 (WLAN or Wi-Fi) , IEEE 802.16 (WiMAX) , Bluetooth, and others.

Carrier Aggregation is a technique which allows a wireless device with multiple communication chains to communicate data using multiple component carriers. Reporting of signal measurements by a mobile device to a base station may impact a Carrier Aggregation configuration implemented by the base station, thus impacting system performance. Improvements in the field would be desirable.

SUMMARY

Embodiments are presented herein of methods for a wireless device to manage its component carriers during carrier aggregation, and of devices configured to implement the methods.

Carrier aggregation (e.g., such as supported in LTE) may include the use of multiple component carriers for data communication by a UE. For example, a secondary component carrier (SCC) may be used together with a primary component carrier (PCC) to receive downlink data and/or transmit uplink data in a carrier aggregation scenario. In such scenarios, the network (e.g., a base station of the serving cell) may determine whether a SCC will be added or released. However, the UE may have additional information regarding whether adding or releasing a SCC would be preferred. Accordingly, it may be useful for a UE to implement techniques to influence whether the serving cell will add or release the SCC.

Techniques are disclosed for a wireless device to determine whether use of the SCC would be preferred in a carrier aggregation scenario, and to take action to encourage or discourage the serving cell to add or release the SCC based on the determination. For example, in some embodiments, when the SCC is preferred, reports of positive performance of the serving cell and/or the neighbor cell may be reported, while reports of negative performance of the serving cell may be delayed or suppressed. Inversely, in some embodiments, when the SCC is not preferred, reports of negative performance of the serving cell may be reported, while reports of positive performance of the serving cell and/or the neighbor cell may be delayed or suppressed. In some embodiments, the UE may determine whether the SCC is preferred based on volume of data traffic.

The techniques described herein may be implemented in and/or used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

This Summary is intended to provide a brief overview of some of the subject matter described in this document. Accordingly, it will be appreciated that the above-described features are merely examples and should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtained when the following detailed description of the embodiments is considered in conjunction with the following drawings, in which:

Figure 1 illustrates an exemplary (and simplified) wireless communication system, according to some embodiments；

Figure 2 illustrates a base station (BS) in communication with a user equipment (UE) device, according to some embodiments；

Figure 3 illustrates an exemplary block diagram of a UE, according to some embodiments；

Figure 4 illustrates an exemplary block diagram of a BS, according to some embodiments；

Figure 5 illustrates an exemplary carrier aggregation scheme, according to some embodiments；

Figure 6 is a diagram illustrating a state machine for a wireless device to periodically determine whether use of a SCC is preferred, according to some embodiments；

Figure 7 is a flowchart diagram illustrating a method for a wireless device to manage signal performance reporting while a secondary component carrier (SCC) is not preferred, according to some embodiments；

Figure 8 is a flowchart diagram illustrating a method for a wireless device to manage signal performance reporting while a SCC is preferred, according to some embodiments.

While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims.

DETAILED DESCRIPTION

Acronyms

Various acronyms are used throughout the present application. Definitions of the most prominently used acronyms that may appear throughout the present application are provided below:

· ACK: Acknowledgement

· BS: Base Station

· CC: Component Carrier

· DL: Downlink (from BS to UE)

· DTX: Discontinuous Transmission

· GPRS: General Packet Radio Service

· GSM: Global System for Mobile Communication

· HARQ: Hybrid Automatic Repeat Request

· LAN: Local Area Network

· LTE: Long Term Evolution

· LTE-A: LTE Advanced

· MAC: Media Access Control (layer)

· NACK: Negative Acknowledgement

· PCC: Primary Component Carrier

· PDCCH: Physical Downlink Control Channel

· PDSCH: Physical Downlink Shared Channel

· PUCCH: Physical Uplink Control Channel

· RAT: Radio Access Technology

· RF: Radio Frequency

· RSRP: Reference Signal Received Power

· RSRQ: Reference Signal Received Quality

· RX: Reception/Receive

· SCC: Secondary Component Carrier

· SNR: Signal-to-Noise Ratio

· TX: Transmission/Transmit

· UE: User Equipment (Device)

· UL: Uplink (from UE to BS)

· UMTS: Universal Mobile Telecommunication System

· VoLTE: Voice over LTE

· WLAN: Wireless LAN

Terms

The following is a glossary of terms used in this disclosure:

Memory Medium –Any of various types of memory devices or storage devices. The term “memory medium” is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape device； a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc. ； a non-volatile memory such as a Flash, magnetic media, e.g., a hard drive, or optical storage； registers, or other similar types of memory elements, etc. The memory medium may comprise other types of memory as well or combinations thereof. In addition, the memory medium may be located in a first computer system in which the programs are executed, or may be located in a second different computer system which connects to the first computer system over a network, such as the Internet. In the latter instance, the second computer system may provide program instructions to the first computer system for execution. The term “memory medium” may include two or more memory mediums which may reside in different locations, e.g., in different computer systems that are connected over a network.

Carrier Medium –a memory medium as described above, as well as a physical transmission medium, such as a bus, network, and/or other physical transmission medium that conveys signals such as electrical, electromagnetic, or digital signals.

Computer System (or Computer) –any of various types of computing or processing systems, including a personal computer system (PC) , mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA) , television system, grid computing system, or other device or combinations of devices. In general, the term "computer system"may be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

User Equipment (UE) (or “UE Device” ) –any of various types of computer systems devices which are mobile or portable and which performs wireless communications. Also referred to as wireless communication devices. Examples of UE devices include mobile telephones or smart phones (e.g., iPhone^TM, Android^TM-based phones) and tablet computers such as iPad^TM, Samsung Galaxy^TM, etc., portable gaming devices (e.g., Nintendo DS^TM, PlayStation Portable^TM, Gameboy Advance^TM, iPod^TM) , laptops, wearable devices (e.g. Apple Watch^TM, Google Glass^TM) , PDAs, portable Internet devices, music players, data storage devices, or other handheld devices, etc. Various other types of devices would fall into this category if they include Wi-Fi or both cellular and Wi-Fi communication capabilities and/or other wireless communication capabilities, for example over short-range radio access technologies (SRATs) such as BLUETOOTH^TM, etc. In general, the term “UE” or “UE device” may be broadly defined to encompass any electronic, computing, and/or telecommunications device (or combination of devices) which is easily transported by a user and capable of wireless communication.

Base Station (BS) –The term "Base Station" has the full breadth of its ordinary meaning, and at least includes a wireless communication station installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

Processing Element –refers to various elements or combinations of elements that are capable of performing a function in a device, e.g. in a user equipment device or in a cellular network device. Processing elements may include, for example: processors and associated memory, portions or circuits of individual processor cores, entire processor cores, processor arrays, circuits such as an ASIC (Application Specific Integrated Circuit) , programmable hardware elements such as a field programmable gate array (FPGA) , as well any of various combinations of the above.

Channel -a medium used to convey information from a sender (transmitter) to a receiver. It should be noted that since characteristics of the term “channel” may differ according to different wireless protocols, the term “channel” as used herein may be considered as being used in a manner that is consistent with the standard of the type of device with reference to which the term is used. In some standards, channel widths may be variable (e.g., depending on device capability, band conditions, etc. ) . For example, LTE may support scalable channel bandwidths from 1.4 MHz to 20MHz. In contrast, WLAN channels may be 22MHz wide while Bluetooth channels may be 1Mhz wide. Other protocols and standards may include different definitions of channels. Furthermore, some standards may define and use multiple types of channels, e.g., different channels for uplink or downlink and/or different channels for different uses such as data, control information, etc.

Band -The term "band" has the full breadth of its ordinary meaning, and at least includes a section of spectrum (e.g., radio frequency spectrum) in which channels are used or set aside for the same purpose.

Automatically –refers to an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuitry, programmable hardware elements, ASICs, etc. ) , without user input directly specifying or performing the action or operation. Thus the term "automatically" is in contrast to an operation being manually performed or specified by the user, where the user provides input to directly perform the operation. An automatic procedure may be initiated by input provided by the user, but the subsequent actions that are performed “automatically” are not specified by the user, i.e., are not performed “manually” , where the user specifies each action to perform. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing information, selecting check boxes, radio selections, etc. ) is filling out the form manually, even though the computer system must update the form in response to the user actions. The form may be automatically filled out by the computer system where the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills in the form without any user input specifying the answers to the fields. As indicated above, the user may invoke the automatic filling of the form, but is not involved in the actual filling of the form (e.g., the user is not manually specifying answers to fields but rather they are being automatically completed) . The present specification provides various examples of operations being automatically performed in response to actions the user has taken.

Configured to –Various components may be described as “configured to” perform a task or tasks. In such contexts, “configured to” is a broad recitation generally meaning “having structure that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently performing that task (e.g., a set of electrical conductors may be configured to electrically connect a module to another module, even when the two modules are not connected) . In some contexts, “configured to” may be a broad recitation of structure generally meaning “having circuitry that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently on. In general, the circuitry that forms the structure corresponding to “configured to” may include hardware circuits.

Various components may be described as performing a task or tasks, for convenience in the description. Such descriptions should be interpreted as including the phrase “configured to. ” Reciting a component that is configured to perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112, paragraph six, interpretation for that component.

Figures 1 and 2 -Communication System

Figure 1 illustrates an exemplary (and simplified) wireless communication system, according to some embodiments. It is noted that the system of Figure 1 is merely one example of a possible system, and embodiments may be implemented in any of various systems, as desired.

As shown, the exemplary wireless communication system includes a base station 102A which communicates over a transmission medium with one or

more user devices

106A, 106B, etc., through 106N. Each of the user devices may be referred to herein as a “user equipment” (UE) . Thus, the user devices 106 are referred to as UEs or UE devices.

The base station 102A may be a base transceiver station (BTS) or cell site, and may include hardware that enables wireless communication with the UEs 106A through 106N. The base station 102A may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN) , and/or the Internet, among various possibilities) . Thus, the base station 102A may facilitate communication between the user devices and/or between the user devices and the network 100.

The communication area (or coverage area) of the base station may be referred to as a “cell. ” The base station 102A and the UEs 106 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs) , also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (WCDMA, TD-SCDMA) , LTE, LTE-Advanced (LTE-A) , HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD) , Wi-Fi, WiMAX etc.

Base station 102A and other similar base stations (such as base stations 102B…102N) operating according to the same or a different cellular communication standard may thus be provided as a network of cells, which may provide continuous or nearly continuous overlapping service to UEs 106A-N and similar devices over a wide geographic area via one or more cellular communication standards.

Thus, while base station 102A may act as a “serving cell” for UEs 106A-N as illustrated in Figure 1, each UE 106 may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which might be provided by base stations 102B-N and/or any other base stations) , which may be referred to as “neighboring cells” . Such cells may also be capable of facilitating communication between user devices and/or between user devices and the network 100, according to the same wireless communication technology as base station 102A and/or any of various other possible wireless communication technologies. Such cells may include “macro” cells, “micro” cells, “pico” cells, and/or cells which provide any of various other granularities of service area size. For example, base stations 102A-B illustrated in Figure 1 might be macro cells, while base station 102N might be a micro cell. Other configurations are also possible.

Note that a UE 106 may be capable of communicating using multiple wireless communication standards. For example, a UE 106 may be configured to communicate using a wireless networking (e.g., Wi-Fi) and/or peer-to-peer wireless communication protocol (e.g., BT, Wi-Fi peer-to-peer, etc. ) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (WCDMA, TD-SCDMA) , LTE, LTE-A, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD) , etc. ) . The UE 106 may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS, e.g., GPS or GLONASS) , one or more mobile television broadcasting standards (e.g., ATSC-M/H or DVB-H) , and/or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

Figure 2 illustrates user equipment 106 (e.g., one of the devices 106A through 106N) in communication with a base station 102 (e.g., one of the base stations 102A through 102N) , according to some embodiments. The UE 106 may be a device with cellular communication capability such as a mobile phone, a hand-held device, a wearable device, a computer or a tablet, or virtually any type of wireless device.

The UE 106 may include a processor that is configured to execute program instructions stored in memory. The UE 106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or in addition, the UE 106 may include a programmable hardware element such as an FPGA (field-programmable gate array) that is configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In one embodiment, the UE 106 might be configured to communicate using either of CDMA2000 (1xRTT /1xEV-DO /HRPD /eHRPD) or LTE using a single shared radio and/or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc. ) , or digital processing circuitry (e.g., for digital modulation as well as other digital processing) . Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 106 may share one or more parts of a receive and/or transmit chain between multiple wireless communication technologies, such as those discussed above.

In some embodiments, the UE 106 may include separate (and possibly multiple) transmit and/or receive chains (e.g., including separate RF and/or digital radio components) for each wireless communication protocol with which it is configured to communicate. As a further possibility, the UE 106 may include one or more radios which are shared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol. For example, the UE 106 might include a shared radio for communicating using either of LTE or 1xRTT (or LTE or GSM) , and separate radios for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

Figure 3 –Exemplary Block Diagram of a UE

Figure 3 illustrates an exemplary block diagram of a UE 106, according to some embodiments. As shown, the UE 106 may include a system on chip (SOC) 300, which may include portions for various purposes. For example, as shown, the SOC 300 may include processor (s) 302 which may execute program instructions for the UE 106 and display circuitry 304 which may perform graphics processing and provide display signals to the display 360. The processor (s) 302 may also be coupled to memory management unit (MMU) 340, which may be configured to receive addresses from the processor (s) 302 and translate those addresses to locations in memory (e.g., memory 306, read only memory (ROM) 350, NAND flash memory 310) and/or to other circuits or devices, such as the display circuitry 304, wireless communication circuitry 330, connector I/F 320, and/or display 360. The MMU 340 may be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU 340 may be included as a portion of the processor (s) 302.

As shown, the SOC 300 may be coupled to various other circuits of the UE 106. For example, the UE 106 may include various types of memory (e.g., including NAND flash 310) , a connector interface 320 (e.g., for coupling to a computer system, dock, charging station, etc. ) , the display 360, and wireless communication circuitry 330 (e.g., for LTE, Wi-Fi, GPS, etc. ) .

The UE device 106 may include at least one antenna (and possibly multiple antennas, e.g., for MIMO and/or for implementing different wireless communication technologies, among various possibilities) , for performing wireless communication with base stations and/or other devices. For example, the UE device 106 may use antenna (s) 335 to perform the wireless communication. As noted above, the UE 106 may be configured to communicate wirelessly using multiple wireless communication technologies in some embodiments.

As described further subsequently herein, the UE 106 may include hardware and software components for implementing features for managing a secondary component carrier, such as those described herein with reference to, inter alia, Figure 6. The processor 302 of the UE device 106 may be configured to implement part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium) . In other embodiments, processor 302 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array) , or as an ASIC (Application Specific Integrated Circuit) . Alternatively (or in addition) , the processor 302 of the UE device 106, in conjunction with one or more of the

other components

300, 304, 306, 310, 320, 330, 335, 340, 350, 360 may be configured to implement part or all of the methods described herein, such as managing performance reporting as described herein with reference to any of Figures 6-8.

Figure 4 –Exemplary Block Diagram of a Base Station

Figure 4 illustrates an exemplary block diagram of a base station 102, according to some embodiments. It is noted that the base station of Figure 4 is merely one example of a possible base station. As shown, the base station 102 may include processor (s) 404 which may execute program instructions for the base station 102. The processor (s) 404 may also be coupled to memory management unit (MMU) 440, which may be configured to receive addresses from the processor (s) 404 and translate those addresses to locations in memory (e.g., memory 460 and read only memory (ROM) 450) or to other circuits or devices.

The base station 102 may include at least one network port 470. The network port 470 may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices 106, access to the telephone network as described above in Figures 1 and 2.

The network port 470 (or an additional network port) may also or alternatively be configured to couple to a cellular network, e.g., a core network of a cellular service provider. The core network may provide mobility related services and/or other services to a plurality of devices, such as UE devices 106. In some cases, the network port 470 may couple to a telephone network via the core network, and/or the core network may provide a telephone network (e.g., among other UE devices serviced by the cellular service provider) .

The base station 102 may include at least one antenna 434, and possibly multiple antennas. The antenna (s) 434 may be configured to operate as a wireless transceiver and may be further configured to communicate with UE devices 106 via radio 430. The antenna 434 communicates with the radio 430 via communication chain 432. Communication chain 432 may be a receive chain, a transmit chain or both. The radio 430 may be configured to communicate via various wireless telecommunication standards, including, but not limited to, LTE, LTE-A, UMTS, CDMA2000, Wi-Fi, etc.

The BS 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some instances, the base station 102 may include multiple radios, which may enable the base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, the base station 102 may include an LTE radio for performing communication according to LTE as well as a Wi-Fi radio for performing communication according to Wi-Fi. In such a case, the base station 102 may be capable of operating as both an LTE base station and a Wi-Fi access point. As another possibility, the base station 102 may include a multi-mode radio which is capable of performing communications according to any of multiple wireless communication technologies (e.g., LTE and Wi-Fi) .

The BS 102 may include hardware and software components for implementing or supporting implementation of features described herein, such as those described herein with reference to, inter alia, Figure 6. The processor 404 of the base station 102 may be configured to implement part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium) . Alternatively, the processor 404 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array) , or as an ASIC (Application Specific Integrated Circuit) , or a combination thereof. Alternatively (or in addition) , the processor 404 of the BS 102, in conjunction with one or more of the

other components

430, 432, 434, 440, 450, 460, 470 may be configured to support implementation of part or all of the features described herein, such as the features described herein with reference to any of Figures 6-8.

Figure 5 -Carrier Aggregation

Carrier aggregation is a scheme in which multiple carriers (e.g., frequency channels) may be used for wireless communication with a UE according to a wireless communication technology. Figure 5 illustrates one exemplary carrier aggregation scheme (e.g., which may be used in accordance with the LTE radio access technology) which may be used in accordance with other aspects of this disclosure, such as with respect to the method of Figure 6.

In the illustrated scheme, up to five component carriers (

carriers

504, 506, 508, 510, 512) may be aggregated for a single user device (such one of the UEs 106 illustrated in and described with respect to Figures 1-3) . Each component carrier may use a channel width of up to 20MHz. As one possibility, each component carrier may be an LTE release 8 carrier. Thus, according to the exemplary scheme, a UE may be allocated up to 100MHz of bandwidth. In many instances, such a carrier aggregation scheme may enable a UE participating in it with greater throughput than without such a scheme.

In many cases, component carriers may utilize adjacent frequency channels. However, it should be noted that it is also possible to implement carrier aggregation utilizing non-continuous frequency channels, potentially including non-continuous frequency channels within the same frequency band, and/or frequency channels within different frequency bands.

For systems which implement carrier aggregation, various control schemes/mechanisms are possible. As one possibility, an independent cell may be implemented on each component carrier, for example by providing a control channel with data scheduling and other control features for each cell on the component carrier for that cell. As another possibility, some or all control functions may be centralized. For example, a "primary cell" might be implemented on one ( "primary" ) component carrier (PCC) , while "secondary cells" might be implemented on any additional ( "secondary" ) component carriers (SCCs) , such that some or all control information for the secondary cells is communicated by way of the primary cell.

In managing carrier aggregation, a network (e.g., a BS of the network, such as a BS of the primary cell) may first add a SCC to the UE. Adding a SCC may include configuring the SCC to interact with the UE on the RRC level. An SCC that has been added to the UE may sometimes be described as being “set up” for the UE. At this stage, the UE may measure signal performance of the SCC, such as downlink power (e.g., RSRP) . The UE typically does not monitor the PDCCH of the SCC at this stage. The network may, if desired, release an SCC that was previously added to the UE. After being released, the carrier may be described as an inter-frequency neighbor carrier of the UE, rather than as an SCC.

Once a SCC has been added, the network may activate the SCC. Activating the SCC may include configuring the SCC to interact with the UE on the MAC level. In many instances, an SCC may be activated only on an “as-needed” basis, and may be used primarily for best effort (e.g., lower-priority) downlink data. For example, a secondary component carrier might be activated if there is downlink data for a UE beyond the amount that can be handled by the primary component carrier for the UE, if radio conditions are sufficiently good for the secondary component carrier. Activation may be by a media access control (MAC) control packet/control element； once the secondary component carrier is activated, a downlink grant may be assigned to the UE on the SCC (e.g., in addition to a downlink grant on the PCC) , and the UE may receive downlink data on both the PCC and the SCC. The UE may monitor the PDCCH for an activated SCC. If the network detects or is informed by the UE that the radio conditions for the secondary component carrier are degraded, or if downlink data for the UE can be handled solely using the primary component carrier, the network may deactivate the secondary component carrier.

In many instances, a network may add a secondary cell in response to an indication that signal performance (e.g., reference signal received power (RSRP) and/or reference signal received quality (RSRQ) ) of a neighbor cell meets a threshold, e.g., indicating that the signal performance of the neighbor cell is sufficient to provide a reliable SCC. For example, the network may add a SCC in response to an LTE A4 event. However, in some scenarios, a UE may report negative performance of the PCC (e.g., an A2 event, reporting that the signal performance of the PCC fails to meet a threshold) before reporting the positive performance of the neighbor cell (e.g., the A4 event) . In such scenarios, the network may not add the SCC, even if the UE would benefit from increased throughput, e.g., if the current volume of data traffic is high.

In other instances, a UE may benefit from the network not adding a SCC, or from the network releasing a previously added SCC. For example, when a UE is conducting a voice over LTE (VoLTE) communication, data traffic may be low, such that increased throughput may not yield significant benefits. Furthermore, when a SCC is added, the PUCCH will be configured according to format 1b with channel selection (1bCS) . This format may result in HARQ-ACK feedback ambiguity, resulting in degraded performance relative to other PUCCH formats, which may be implemented when no SCC is added.

For example, Table 1 illustrates HARQ-ACK feedback ambiguity that may result from format 1bCS with M＝4 (one uplink subframe contains PDSCH result for four downlink subframes) . As shown, the reception status for each subframe may be fed back as any of three possible feedback values: ACK (acknowledgement) , NACK (negative acknowledgement) , or DTX (discontinuous transmission) . Reporting the status of each of two cells operating with carrier aggregation results in a total of eight subframes to be reported. Thus, the maximum number of possible feedback combinations to be reported is 3^8. However, an insufficient number of bits are available for reporting that number of possible combinations. As shown in Table 1, certain combinations of reporting bits (Constellation and RM Code Input Bits fields) may be used to indicate multiple combinations of feedback reports. This ambiguity may result in the UE misinterpreting the feedback, which may lead to degraded performance.

Table 1: Transmission of HARQ-ACK Multiplexing for M＝4

It should be noted that while the exemplary scheme illustrated in Figure 5 and the associated description are provided by way of example as one possible manner of implementing carrier aggregation, they are not intended to be limiting to the disclosure as a whole. Numerous alternatives to and variations of the details thereof are possible and should be considered within the scope of the present disclosure. For example: carrier aggregation schemes may be implemented in conjunction with other wireless communication technologies； carriers according to other LTE releases or other radio access technologies altogether may be used； carriers having different channel widths may be used； different numbers of component carriers may be supported； and/or any of numerous other alternatives to and variations of the illustrated scheme are also possible.

Figure 6 -Secondary Component Carrier Preference

As noted above, carrier aggregation (e.g., such as supported in LTE) may include the use of multiple component carriers for data communication by a UE. For example, a secondary component carrier (SCC) may be used together with a primary component carrier (PCC) to receive downlink data and/or transmit uplink data in a carrier aggregation scenario. In such scenarios, the primary cell (e.g., a base station of the primary cell) may determine whether a SCC will be added or released. However, the UE may have additional information regarding whether adding or releasing a SCC would be preferred. Accordingly, it may be useful for a UE to implement techniques to determine whether a SCC would be preferred, and to take action to encourage or discourage the serving cell to add or release the SCC.

Figure 6 is a diagram illustrating a state machine for a wireless device to periodically determine whether use (e.g., setup) of a SCC is preferred, according to some embodiments. Specifically, in identifying whether use of the SCC is “preferred, ” the UE may seek to determine whether use of the SCC is likely to improve (or not detriment) system performance. The wireless device may be or include, e.g., a UE 106, or some component thereof, such as the wireless communication circuitry 330 or a baseband processor thereof.

As illustrated in Figure 6, the wireless device may operate in either a “SCC is preferred” state 602 or a “SCC is not preferred” state 604. The wireless device may periodically evaluate whether use of an SCC is preferred, and transition between states in response to the evaluation. In each period, the wireless device may evaluate whether use of the SCC is currently preferred based on the current service requirement. For example, the service requirement may be defined in terms of volume of data traffic, e.g., data rate. The data rate may be quantized, e.g., in terms of number of downlink grants per unit of time. For example, the data rate may be defined as a downlink scheduled subframe number divided by total subframe number for a defined time period. The defined time period may be, e.g., the preceding evaluation period, or some fraction thereof, such as half of the preceding evaluation period.

The state machine may be set to the “SCC is preferred” state 602 by default. In some embodiments this may be implemented, e.g., by setting a variable S_{SCC_Preferred} to true.

In some embodiments, at the start of a first period, the wireless device may compare a current rate of data traffic to one or more thresholds. For example, while the wireless device is in the “SCC is preferred” state 602, it may determine that the current rate of data traffic meets (or exceeds) a threshold T_{high_data_traffic}. In response, the wireless device may remain in the “SCC is preferred” state 602, as illustrated in Figure 6 by state transition 610. As one example, T_{high_data_traffic} may be set such that it is met only by continuous DL grants. In other examples, T_{high_data_traffic} may be set to some lower value.

Alternatively, while the wireless device is in the “SCC is preferred” state 602, it may determine that the current rate of data traffic does not meet (or exceed) a threshold T_{low_data_traffic}. In response, the wireless device may transition to the “SCC is not preferred” state 604, as illustrated in Figure 6 by state transition 620. In some embodiments this may be implemented, e.g., by setting a variable S_{SCC_Preferred} to false. As one example, T_{low_data_traffic} may be set such that typical rates of data traffic associated with VoLTE communications would not meet T_{low_data_traffic}. In other examples, T_{low_data_traffic} may be set to some higher or lower value.

Similarly, while the wireless device is in the “SCC is not preferred” state 604, it may determine that the current rate of data traffic meets (or exceeds) the threshold T_{high_data_traffic}. In response, the wireless device may transition to the “SCC is preferred” state 602, as illustrated in Figure 6 by state transition 630, e.g., by setting a variable S_{SCC_Preferred} to true.

Alternatively, while the wireless device is in the “SCC is not preferred” state 604, it may determine that the current rate of data traffic does not meet (or exceed) the threshold T_{low_data_traffic}. In response, the wireless device may remain in the “SCC is not preferred” state 604, as illustrated in Figure 6 by state transition 640.

In some embodiments T_{low_data_traffic} may be equal to T_{high_data_traffic}. In other embodiments, T_{low_data_traffic} may be lower than T_{high_data_traffic}. If the wireless device determines that the current rate of data traffic falls between the two thresholds (i.e., the current rate of data traffic is higher than T_{low_data_traffic} but lower than T_{high_data_traffic}) , then the wireless device may remain in its current state.

In other embodiments, the wireless device may employ only one data traffic threshold. For example, the wireless device may transition to (or remain in) the “SCC is preferred” state 602, as illustrated in Figure 6 by state transition 630 (or state transition 610) in response to determining that the current rate of data traffic meets the threshold T_{high_data_traffic}, and may transition to (or remain in) the “SCC is not preferred” state 604, as illustrated in Figure 6 by state transition 620 (or state transition 640) in response to determining that the current rate of data traffic does not meet the threshold T_{high_data_traffic}. As one example, in such embodiments, T_{high_data_traffic} may be set such that typical rates of data traffic associated with VoLTE communications would not meet T_{high_data_traffic}. In other examples, T_{high_data_traffic} may be set to some higher or lower value.

At the end of each evaluation period and/or during each evaluation period, the wireless device may perform measurement reporting steps based on the state transition followed at the start of the evaluation period, and further based on measurements determined during the present and/or previous evaluation periods. In general terms, it may be noted that reporting positive performance of the serving cells (e.g., of the PCC and SCC) and/or a neighbor cell may encourage, or cause, the network to add the SCC, or to not release the SCC, if previously added. By contrast, reporting negative performance of the serving cells and/or the neighbor cell may discourage the network from adding the SCC, or may encourage the network to release the SCC, if previously added. Thus, by manipulating reports of performance measurements of the serving cells and/or the neighbor cell, the wireless device may be able to influence whether the SCC is added or released, based on a determination by the wireless device regarding whether the SCC is preferred.

For example, when the SCC is preferred, one or more reports of positive performance of the serving cells and/or the neighbor cell may be reported, while one or more reports of negative performance of the serving cells may be delayed or suppressed. Inversely, when the SCC is not preferred, one or more reports of negative performance of the serving cells may be reported, while one or more reports of positive performance of the serving cells and/or the neighbor cell may be delayed or suppressed.

However, when manipulating reports of performance measurements, constraints may be applied to avoid unduly disrupting other functions that rely on the performance measurements. Specific examples of various manipulations of performance measurements, as well as constraints that may be applied, are further described with reference to Figures 7-8.

Figure 7 –Remaining in the SCC Not Preferred State

Figure 7 is a flowchart diagram illustrating a method for a wireless device to manage signal performance reporting while in the “SCC is not preferred” state 604, according to some embodiments. The method shown in Figure 7 may be used in conjunction with any of the computer systems or devices shown in the above Figures, among other devices. In various embodiments, some of the elements of the scheme shown may be performed concurrently, in a different order than shown, or may be omitted. Additional elements may also be performed as desired. As shown, the scheme may operate as follows.

At 702, the wireless device may determine that use of a SCC is not currently preferred. For example, this method may be performed according to transition 620 or transition 640 of Figure 6, e.g., by determining that the current rate of data traffic does not meet (or exceed) a threshold value. In some embodiments, the determining that use of the SCC is not currently preferred may include determining that the rate of data traffic has not met the threshold value for at least a predefined period of time, e.g., one or more of the evaluation periods of Figure 6. Such embodiments may thus be performed according to the transition 640 of Figure 6, and not according to the transition 620.

At 704, the wireless device may determine whether the SCC is currently set up； i.e., whether the SCC was previously added, as described above with regard to Figure 5.

In response to determining, at 702, that use of the SCC is not currently preferred and, at 704, that the SCC is currently set up, the wireless device may take steps to encourage the network (e.g., a BS of the primary cell) to release the SCC. For example, at 706, the wireless device may detect whether performance conditions of the PCC are satisfactory. For example, the wireless device may determine (e.g., measure) one or more performance metrics of the PCC, and compare them to one or more respective performance thresholds. The one or more performance metrics of the PCC may be measures of performance of the PCC. As a specific example, the wireless device may determine one or more (e.g., all) of RSRP, RSRQ, and/or signal-to-noise ratio (SNR) of the PCC, and may compare the determined value (s) to one or more threshold values T_RSRP2, T_RSRQ2, and/or T_SNR2, respectively.

In response to detecting, at 706, that the performance conditions of the PCC are satisfactory, the wireless device may falsely (e.g., artificially) report (e.g., generate and transmit a false report to the network) that a performance metric of the SCC (M_{S_SCC}) does not meet a performance threshold T_{A2_SCC}. The performance metric M_{S_SCC} may represent a measure of performance of the SCC, and the performance threshold T_{A2_SCC} may represent a specified value of the measure, defined such that measured values not meeting the performance threshold T_{A2_SCC} indicate poor performance of the communications. For example, the performance metric M_{S_SCC} may be, include, or represent one or more measurements of RSRP, RSRQ, and/or SNR for the SCC, and the performance threshold T_{A2_SCC} may include minimum acceptable value (s) of the measurement (s) . As a further example, if the wireless device is communicating according to an LTE protocol, the performance threshold T_{A2_SCC} may be or reflect a threshold defined for an A2 event of the SCC, with or without an associated hysteresis value, and the performance metric M_{S_SCC} may be a measurement defined for use in detecting the A2 event of the SCC. Thus, in some embodiments, reporting that the performance metric M_{S_SCC} does not meet the performance threshold T_{A2_SCC} may be similar or equivalent to, or may include, reporting an A2 event of the SCC. It should be noted that, in some scenarios, the performance metric M_{S_SCC} may actually not meet the performance threshold T_{A2_SCC} (and the wireless device may detect that condition, e.g., according to normal operations) . However, the report of operation 708 may nevertheless be considered to be a “false” report, in that the wireless device transmits the report without regard to whether the performance metric M_{S_SCC} meets the performance threshold T_{A2_SCC} (and, in some embodiments, without detecting whether that condition is met) .

As previously noted, a negative performance report of the SCC may cause the network to release the SCC. Thus, the false report of operation 708 may cause the SCC to be released, which is the desired result in light of the determination, at 702, that the SCC is not currently preferred.

In response to detecting, at 706, that the performance conditions of the PCC are not satisfactory, the wireless device may, at 710, report detected events (such as A2 of the PCC and/or SCC, or other events) to the network (e.g., to a BS of the primary cell) , e.g., according to the specifications of the communication protocol by which the wireless device is communicating (e.g., without false reports) . Specifically, it should be noted that falsely reporting negative performance of the SCC (such as an A2 event) may negatively impact proper handover between cells. Thus, in some embodiments, the wireless device may define the one or more performance thresholds of the one or more performance metrics of the PCC (e.g., T_RSRP2, T_RSRQ2, and/or T_SNR2) to represent an absolute performance threshold that performance of the PCC must meet before the wireless device will falsely report negative performance of the SCC. For example, the one or more performance thresholds may be defined as values such that, if the one or more performance metrics of the PCC meet the respective one or more thresholds, the wireless device may be confident that handover is unlikely to be performed imminently. Thus, in some embodiments, if the one or more performance metrics of the PCC meet the one or more respective thresholds, then a false report regarding negative performance of the SCC may be transmitted without significant concern of negatively impacting handover, and otherwise the wireless device may report detection of various performance measurement events to the network, e.g., according to normal procedures of the communication protocol.

In response to determining, at 702, that use of the SCC is not currently preferred and, at 704, that the SCC is not currently set up, the wireless device may take steps to discourage the network from adding the SCC. For example, at 712, the wireless device may detect whether one or more conditions are satisfied for suppressing a report of a measurement event. Specifically, the wireless device may detect whether a performance metric of a neighbor cell (M_N) meets a performance threshold T_A4, and possibly whether a performance metric M_{S_PCC} meets a performance threshold T_{A2_PCC}, and whether performance conditions of the PCC are satisfactory.

The performance metric M_N may be a measure of performance of communications between a BS of the neighbor cell and the wireless device, and may report a value similar to that of the performance metric M_{S_SCC}. For example, the performance metric M_N may be, include, or represent one or more measurements of RSRP, RSRQ, and/or SNR for the neighbor BS, and the performance threshold T_A4 may include minimum acceptable value (s) of the measurement (s) . As a further example, if the wireless device is communicating according to an LTE protocol, the performance threshold T_A4 may be or reflect a threshold defined for an A4 event, with or without associated hysteresis and/or offset values, and the performance metric M_N may be a measurement defined for use in detecting the A4 event. Thus, in some embodiments, detecting that the performance metric M_N meets the performance threshold T_A4 may be similar or equivalent to detecting an A4 event.

The performance metric M_{S_PCC} may be similar to the performance metric M_{S_SCC}, but may represent a measure of performance of the PCC, and the performance threshold T_{A2_PCC} may represent a specified value of the measure, defined such that measured values not meeting the performance threshold T_{A2_PCC} indicate poor performance of the communications. T_{S2_PCC} may or may not be the same value as the performance threshold T_{A2_SCC}. For example, the performance metric M_{S_PCC} may be, include, or represent one or more measurements of RSRP, RSRQ, and/or SNR for the PCC, and the performance threshold T_{A2_PCC} may include minimum acceptable value (s) of the measurement (s) . As a further example, if the wireless device is communicating according to an LTE protocol, the performance threshold T_{A2_PCC} may be or reflect a threshold defined for an A2 event of the PCC, with or without an associated hysteresis value, and the performance metric M_{S_PCC} may be a measurement defined for use in detecting an A2 event of the PCC. Thus, in some embodiments, detecting that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC} may be similar or equivalent to, or may include, detecting an A2 event of the PCC.

Detecting whether performance conditions of the PCC are satisfactory may be carried out as discussed above.

In response to determining, at 712, that the conditions are satisfied for suppressing a report of a measurement event (e.g., in response to detecting that the performance metric M_N meets the performance threshold T_A4, and possibly that the performance metric M_{S_PCC} meets the performance threshold T_{A2_PCC}, and that the performance conditions of the PCC are satisfactory) , the wireless device may, at 716, not report to the network that the performance metric M_N meets a performance threshold T_A4. Specifically, the wireless device may be communicating with the network according to a communication protocol (e.g., LTE) that specifies (e.g., requires, dictates, suggests, or encourages) that the wireless device report detection that the performance metric M_N meets the performance threshold T_A4. Thus, the wireless device not reporting this detection to the network may include suppressing (e.g., not generating and/or not transmitting) a report that is typical, expected, or required according to the communication protocol. As noted above, reporting positive performance of the neighbor cell may encourage, or cause, the network to add the SCC. Thus, when use of the SCC is not currently preferred, such a positive performance report may be suppressed to avoid addition of the SCC.

However, in response to determining, at 712, that the conditions for suppressing a report of a measurement event are not satisfied, the wireless device may take no special action. For example, the wireless device may, at 710, report detected events, e.g., according to the specifications of the communication protocol by which the wireless device is communicating.

As a specific example, if the wireless device does not detect, at 712, that the performance metric M_N meets a performance threshold T_A4 (e.g., before the end of the evaluation period or based on a first one or more samples of the evaluation period) , then no suppression of that event is needed, and normal reporting may proceed at 710, e.g., according to the communication protocol.

As a second specific example, in some embodiments, if the wireless device detects, at 712, that the performance metric M_{S_PCC} fails to meet the performance threshold T_{A2_PCC}, then the wireless device may report this detection to the network, e.g., according to normal procedures of the communication protocol. As noted above, reporting of negative performance of the serving cell may discourage addition of the SCC. Thus, reporting of this negative performance may outweigh positive reporting of the performance of the neighbor cell, such that reporting both that the performance metric M_{S_PCC} fails to meet the performance threshold T_{A2_PCC} (e.g., such as an A2 event) and that the performance metric M_N meets a performance threshold T_A4 (e.g., such as an A4 event) may still result in the SCC not being added. By not unnecessarily suppressing a measurement event report, the wireless device may avoid negatively impacting other functions that rely on such reports, such as handover. In particular, if the performance metric M_{S_PCC} fails to meet the performance threshold T_{A2_PCC} (e.g., such as an A2 event) , this may indicate that a handover event may soon occur, in which case suppressing positive reporting of the neighbor cell may be detrimental. Thus, in some embodiments, the conditions tested at 712 may include detecting whether the performance metric M_{S_PCC} meets the performance threshold T_{A2_PCC}.

As a third specific example, if the wireless device detects, at 712, that the performance conditions of the PCC are not satisfactory, then the wireless device may report detection of various performance measurement events (e.g., A2 and/or A4 events, as discussed above) to the network, e.g., according to normal procedures of the communication protocol. Specifically, it should be noted that suppressing a report regarding positive performance of a neighbor cell (such as an A4 event) may negatively impact proper handover between cells. Thus, in some embodiments, the wireless device may define the one or more performance thresholds of the one or more performance metrics of the PCC as defined above (e.g., T_RSRP2, T_RSRQ2, and/or T_SNR2) to further represent an absolute performance threshold that performance of the PCC must meet before the wireless device will suppress a report regarding positive performance of the neighbor cell. For example, the one or more performance thresholds may be defined as values such that, if the one or more performance metrics of the PCC meet the respective one or more thresholds, the wireless device may be confident that handover is unlikely to be performed imminently. Thus, in some embodiments, if the one or more performance metrics of the PCC meet the one or more respective thresholds, then a report regarding positive performance of the neighbor cell may be suppressed without significant concern of negatively impacting handover, and otherwise the wireless device may report detection of various performance measurement events to the network, e.g., according to normal procedures of the communication protocol.

In some embodiments, the one or more performance thresholds of the one or more performance metrics of the PCC may be defined to be similar in nature, but higher in value, than the performance threshold T_{A2_PCC}. For example, the performance threshold T_{A2_PCC} may be a threshold RSRP value, and the one or more performance thresholds of the PCC may include a higher threshold RSRP value. In such embodiments, detecting that the performance conditions of the PCC are satisfactory may inherently include detecting that the performance metric M_{S_PCC} meets the lower performance threshold T_{A2_PCC}. Thus, in such embodiments, operation 712 may include only detecting whether the performance metric M_N meets the performance threshold T_A4 and whether the performance conditions of the PCC are satisfactory (i.e., without expressly detecting whether the performance metric M_{S_PCC} meets the performance threshold T_{A2_PCC}) .

In some embodiments, the wireless device may, at 712, monitor for the conditions for suppressing a report of a measurement event throughout the evaluation period, and decide at the end of the evaluation period which events to report to the network. For example, if the wireless device determines that all of the criteria are satisfied during the evaluation period, then, at the end of the evaluation period, the wireless device may not transmit the report that the performance metric M_N met a performance threshold T_A4. In other embodiments, the wireless device may decide to send one or more reports before the end of the evaluation period. For example, if the wireless device determines that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC}, then the wireless device may (e.g., immediately) proceed to operation 710 and first report that determination. In that example, the wireless device may then follow the first report with a second report that the performance metric M_N meets the performance threshold T_A4, e.g., immediately following the first report if such an event had been detected earlier in the evaluation period, or immediately upon detection if such an event is detected later in the evaluation period.

As noted above, in various embodiments, some of the elements of the scheme shown may be performed concurrently, in a different order than shown, or may be omitted. Additional elements may also be performed as desired. For example, the wireless device may operate to take steps to discourage the network from adding the SCC (e.g., according to the “No” branch of operation 704) , but not to take steps to encourage the network to release the SCC if set up (e.g., according to the “Yes” branch of operation 704) , or vice versa.

Figure 8 –Transitioning to the SCC Preferred State

Figure 8 is a flowchart diagram illustrating a method for a wireless device to manage signal performance reporting while in the “SCC is preferred” state 602, according to some embodiments. The method shown in Figure 8 may be used in conjunction with any of the computer systems or devices shown in the above Figures, among other devices. In various embodiments, some of the elements of the scheme shown may be performed concurrently, in a different order than shown, or may be omitted. Additional elements may also be performed as desired. As shown, the scheme may operate as follows.

At 802, the wireless device may determine that use of a SCC is currently preferred. For example, this method may be performed according to transition 610 or transition 630 of Figure 6, e.g., by determining that the current rate of data traffic meets (or exceeds) the threshold value. In some embodiments, the determining that use of the SCC is currently preferred may include determining that the rate of data traffic has met the threshold value for less than a predefined period of time, e.g., one or more of the evaluation periods of Figure 6. Such embodiments may thus be performed according to the transition 630 of Figure 6, and not according to the transition 610. In such embodiments, the wireless device may, in response to determining that the rate of data traffic has met the threshold value for at least the predefined period of time, e.g., according to the transition 610, report detected performance measurement events (such as A1, A2, A4, or other events) to the network, e.g., according to the specifications of the communication protocol by which the wireless device is communicating.

At 804, the wireless device may determine whether the SCC is currently set up； i.e., whether the SCC was previously added, as described above with regard to Figure 5.

In response to determining that use of the SCC is currently preferred and that the SCC is currently set up, the wireless device may, at 806, report detected performance measurement events as detected, e.g., according to the specifications of the communication protocol by which the wireless device is communicating.

In response to determining that use of the SCC is currently preferred and that the SCC is currently not set up, the wireless device may take steps to encourage the network (e.g., a BS of the primary cell) to add the SCC. For example, at 808, the wireless device may detect whether the performance metric M_{S_PCC} meets the performance threshold T_{A2_PCC} and whether the performance metric M_N meets the performance threshold T_A4. These performance metrics, thresholds, and determinations may be as described above with regard to Figure 7. Specifically, if the wireless device detects that the performance metric M_{S_PCC} meets the performance threshold T_{A2_PCC} and that the performance metric M_N meets the performance threshold T_A4, then the wireless device may proceed to operation 806 and report detected performance measurement events as detected, e.g., according to the specifications of the communication protocol by which the wireless device is communicating. For example, if the wireless device is communicating according to an LTE protocol, then this condition may reflect or include detecting an A4 event, while not detecting an A2 event of the PCC. As noted above, reporting positive performance of the neighbor cell may encourage, or cause, the network to add the SCC, while reporting negative performance of the PCC may discourage the network from adding the SCC. Thus, in a scenario in which SCC addition is desired, normal reporting may be desirable where such will result in reporting positive performance of the neighbor cell, without reporting negative performance of the PCC.

In response to determining, at 808, either that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC} or that the performance metric M_N does not meet the performance threshold T_A4, then the wireless device may, at 810, detect whether one or more conditions are satisfied for delaying a report of a measurement event. For example, the wireless device may detect whether the performance metric M_{S_PCC} meets the performance threshold T_{A2_PCC}, whether the performance metric M_N meets the performance threshold T_A4, and whether performance conditions of the PCC are satisfactory. Specifically, the wireless device may determine that one or more conditions are satisfied for delaying a report of a measurement event upon detecting that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC}, and that the performance metric M_N meets the performance threshold T_A4, and that the performance conditions of the PCC are satisfactory.

To determine whether the performance conditions of the PCC are satisfactory, the wireless device may determine (e.g., measure) one or more performance metrics of the PCC, and compare them to one or more respective performance thresholds, in a manner similar to that described with regard to operation 706 of Figure 7. The one or more performance metrics of the PCC may be measures of performance of the PCC. As a specific example, the wireless device may determine one or more (e.g., all) of RSRP, RSRQ, and/or signal-to-noise ratio (SNR) of the PCC, and may compare the determined value (s) to one or more threshold values T_RSRP1, T_RSRQ1, and/or T_SNR1, respectively. It should be understood that the one or more respective performance thresholds of operation 810 (e.g., T_RSRP1, T_RSRQ1, and/or T_SNR1) may differ from the one or more respective performance thresholds of operation 706 (e.g., T_RSRP2, T_RSRQ2, and/or T_SNR2) .

Thus, the conditions for delaying a report of a measurement event may include a negative performance event of the PCC (e.g., an A2 event) , a positive performance event of the neighbor cell (e.g., an A4 event) , and a determination that the PCC is performing above a specified performance level, despite the negative performance event.

It should be appreciated that the flowchart of Figure 8 is a logical flowchart, rather than a chronological flow chart. For example, although each of

operations

808 and 810 detect whether the performance metric M_{S_PCC} meets the performance threshold T_A2 and whether the performance metric M_N meets the performance threshold T_A4, these may reflect the same detections； the different operations may simply indicate different logical flows that may result from differing combinations of the detected conditions. For example, the wireless device may determine, e.g., at the end of the current evaluation period, which of the conditions evaluated in

operations

808 and 810 have been satisfied during the current evaluation period, and perform the appropriate operation at that time. Specifically, the wireless device may delay all performance event reporting at least until the end of the current evaluation period. Then, based on all performance events detected during the current evaluation period, the wireless device may perform one of

operation

806, 814, or 816, as illustrated in Figure 8.

Because the wireless device may wait to report the detection of performance measurement events until at least the end of the current evaluation period, in some embodiments, the length of the evaluation periods may be selected so as to be sufficiently short to allow timely reporting of detected events. For example, in some embodiments, the evaluation period may be equal to a minimum time to trigger (TTT) timer configured for relevant events (e.g., A1, A2, and A4 events) .

If the wireless device detects, at 810, that the conditions for delaying a report of a measurement event are not satisfied, then the wireless device may proceed to operation 806 and report detected performance measurement events as detected, e.g., according to the specifications of the communication protocol by which the wireless device is communicating.

If the wireless device instead detects, at 810, that the conditions for delaying a report of a measurement event are satisfied, then the wireless device may, at 812, determine whether the current evaluation period (of Figure 6) is the first evaluation period following attachment of the wireless device to the primary cell.

In response to determining, at 812, that the current evaluation period is the first evaluation period following attachment, the wireless device may, at 814, delay reporting to the network that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC} until after reporting that the performance metric M_N meets the performance threshold T_A4. For example, at the end of the current evaluation period, the wireless device may report that the performance metric M_N meets the performance threshold T_A4. The wireless device may afterward report that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC}, e.g., at the end of the next evaluation period. As noted above, reporting positive performance of the neighbor cell (such as an A4 event) may encourage, or cause, the network to add the SCC, while reporting negative performance of the PCC (such as an A2 event) may discourage the network from adding the SCC. Thus, by first reporting that the performance metric M_N meets the performance threshold T_A4, the wireless device may provide an opportunity for the network to add the SCC before receiving the second report that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC}. Subsequently reporting the second report is unlikely, by itself, to cause the network to release the SCC, once added.

In response to determining, at 812, that the current evaluation period is not the first evaluation period following attachment, the wireless device may, at 814, delay reporting to the network that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC} and that the performance metric M_N meets the performance threshold T_A4 until after falsely reporting that the performance metric M_{S_PCC} meets a performance threshold T_A1.

The performance threshold T_A1 may represent a specified value of the measure of M_{S_PCC}, defined such that measured value meeting the performance threshold T_A2 indicate satisfactory (or improving) performance of the communications. For example, the performance metric M_{S_PCC} may be, include, or represent one or more measurements of RSRP, RSRQ, and/or SNR for the PCC, and the performance threshold T_A1 may include minimum acceptable value (s) of the measurement (s) . As a further example, if the wireless device is communicating according to an LTE protocol, the performance threshold T_A1 may be or reflect a threshold defined for an A1 event, with or without an associated hysteresis value, and the performance metric M_{S_PCC} may be a measurement defined for use in detecting the A1 event. Thus, in some embodiments, reporting that the performance metric M_{S_PCC} meets the performance threshold T_A1 may be similar or equivalent to, or may include, reporting an A1 event. It should be noted that, in some scenarios, the performance metric M_{S_PCC} may actually meet the performance threshold T_A1 (and the wireless device may detect that condition, e.g., according to normal operations) . However, the report of operation 816 may nevertheless be considered to be a “false” (e.g. artificial) report, in that the wireless device transmits the report without regard to whether the performance metric M_{S_PCC} meets the performance threshold T_A1 (and, in some embodiments, without detecting whether that condition is met) .

As a specific example of the operation 816, at the end of the current evaluation period, the wireless device may falsely first report that the performance metric M_{S_PCC} meets the performance threshold T_A1. It should be noted that execution of operation 816 requires that at least one evaluation period has passed since attachment of the wireless device to the primary cell, without the SCC being added. This condition may result, e.g., from a negative report of the performance of the PCC during a previous evaluation period. Thus, the false first report that the performance metric M_{S_PCC} meets the performance threshold T_A1 during the current reporting period may indicate to the network that the performance of the PCC is improving. Following the first report (e.g., immediately following or at the end of the next evaluation period) , the wireless device may report that the performance metric M_N meets the performance threshold T_A4. The wireless device may afterward report that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC}, e.g., at the end of the next evaluation period following the report that the performance metric M_N meets the performance threshold T_A4. As noted above, reporting positive performance of the neighbor cell (such as an A4 event) may encourage, or cause, the network to add the SCC, while reporting negative performance of the PCC (such as an A2 event) may discourage the network from adding the SCC. Thus, by first reporting that the performance metric M_N meets the performance threshold T_A4, the wireless device may provide an opportunity for the network to add the SCC before receiving the second report that the performance metric M_{S_PCC} does not meet the performance threshold T_{A2_PCC}. Previously reporting that the performance metric M_{S_PCC} meets the performance threshold T_A1 may signal to the network that the PCC is performing at a level sufficient to support addition of a SCC. Subsequently reporting the second report is unlikely, by itself, to cause the network to release the SCC, once added.

It should be noted that delaying a report regarding negative performance of the serving cell or falsely reporting positive performance of the PCC may impact proper handover between cells. Thus, in some embodiments, the wireless device may define the one or more performance thresholds of the one or more performance metrics of the PCC (e.g., T_RSRP1, T_RSRQ1, and/or T_SNR1) to represent an absolute performance threshold that performance of the PCC must meet before the wireless device will delay or falsify a performance report. For example, the one or more performance thresholds may be defined as values such that, if the one or more performance metrics of the PCC meet the respective one or more thresholds, the wireless device may be confident that a delay in reporting the negative performance of the PCC and a false report of positive performance of the PCC are unlikely to cause significant performance degradation； e.g., that handover to a neighbor cell is unlikely to be immediately necessary. Thus, in some embodiments, if the performance conditions of the PCC are satisfied, then a report regarding negative performance of the PCC may be delayed, and/or a report regarding positive performance of the PCC may be falsified, without significant concern of impacting handover. Otherwise the wireless device may proceed to operation 806 and report detected performance measurement events to the network as detected, e.g., according to the specifications of the communication protocol by which the wireless device is communicating.

Embodiments of the present disclosure may be realized in any of various forms. For example, some embodiments may be realized as a computer-implemented method, a computer-readable memory medium, or a computer system. Other embodiments may be realized using one or more custom-designed hardware devices such as ASICs. Still other embodiments may be realized using one or more programmable hardware elements such as FPGAs.

In some embodiments, a non-transitory computer-readable memory medium may be configured so that it stores program instructions and/or data, where the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of a method embodiments described herein, or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106) may be configured to include a processor (or a set of processors) and a memory medium, where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method embodiments described herein (or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets) . The device may be realized in any of various forms.

Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

A method for managing performance reporting to a network by a user equipment device (UE) capable of performing carrier aggregation, the method comprising: by the UE:

determining that use of a secondary component carrier (SCC) of the network is not currently preferred；

detecting that one or more first performance metrics of a primary component carrier (PCC) of the network meet respective one or more first performance thresholds； and

transmitting to a base station of the network, in response to determining that use of the SCC is not currently preferred, a false report that a second performance metric of the SCC does not meet a second performance threshold.
The method of claim 1, further comprising:

detecting that the SCC is set up for use by the UE；

wherein transmitting the false report is further in response to the detecting that the SCC is currently set up for use by the UE.
The method of claim 1, wherein the one or more first performance metrics comprise at least one of a Reference Signal Received Power (RSRP) measurement, a Reference Signal Received Quality (RSRQ) measurement, and a signal-to-noise ratio (SNR) measurement.
The method of claim 1, wherein determining that use of the SCC is not currently preferred comprises determining that current data rate is lower than a data rate threshold.
The method of claim 1, wherein determining that use of the SCC is not currently preferred comprises determining that a current data rate has remained lower than a data rate threshold for a predefined period of time.
A method for managing performance reporting to a network by a user equipment device (UE) capable of performing carrier aggregation, the method comprising: by the UE:

determining that use of a secondary component carrier (SCC) of the network is not currently preferred； and

detecting that a performance metric of a neighbor cell of the network meets a first performance threshold, wherein, in response to determining that use of the SCC is not currently preferred, the UE does not report the detecting to the network.
The method of claim 6, wherein the UE communicates with the base station according to a communication protocol that specifies that the UE report detection that the performance metric of the neighbor cell meets the first performance threshold.
The method of claim 6, further comprising:

detecting that one or more performance metrics of a primary component carrier (PCC) of the network meet one or more respective second performance thresholds； and

detecting that the SCC is not currently set up for use by the UE；

wherein the UE not reporting the detecting to the network is further in response to the detecting that the one or more performance metrics of the PCC meet the one or more respective second performance thresholds and the detecting that the SCC is not currently set up for use by the UE.
The method of claim 6, wherein the performance metric of the neighbor cell comprises at least one of a Reference Signal Received Power (RSRP) measurement and a Reference Signal Received Quality (RSRQ) measurement.
The method of claim 6, wherein the determining that use of a SCC of the network is not currently preferred comprises determining that a current data traffic rate is lower than a data traffic threshold.
A apparatus comprising:

at least one processor； and

a memory medium storing software instructions executable by the at least one processor to cause the apparatus to:

determine that use of a secondary component carrier (SCC) of a network is not currently preferred；

determine whether the SCC is currently set up for use by the apparatus；

in response to determining that that the SCC is currently set up for use by the apparatus, and further in response to the determining that use of the SCC is not currently preferred, and further in response to detecting that one or more first performance metrics of a primary component carrier (PCC) of the network meet one or more respective first performance thresholds:

generate a false first report to the network that the SCC does not meet a second performance threshold； and

in response to determining that that the SCC is not currently set up for use by the apparatus, and further in response to the determining that use of the SCC is not currently preferred, and further in response to detecting that a performance metric of a neighbor cell meets a third performance threshold:

omit a second report to the network that the performance metric of the neighbor cell meets the third performance threshold, wherein a communication protocol used by the apparatus to communicate with the network specifies that the second report be sent in response to detecting that the performance metric of the neighbor cell meets the third performance threshold.
The apparatus of claim 11, wherein omitting the second report is further in response to detecting that the one or more first performance metrics of the PCC meet the one or more respective first performance thresholds.
The apparatus of claim 11, wherein at least one of the first performance metric and the second performance metric comprises at least one of a Reference Signal Received Power (RSRP) measurement, a Reference Signal Received Quality (RSRQ) measurement, and a signal-to-noise ratio (SNR) measurement.
The apparatus of claim 11, wherein, in determining that use of a SCC is not currently preferred, the software instructions are further executable by the at least one processor to cause the apparatus to:

determine that a current data traffic rate is lower than a data traffic threshold.
The apparatus of claim 14, wherein the data traffic threshold is higher than a data traffic rate of Voice over LTE (VoLTE) communication.
A method for managing performance reporting to a network by a user equipment device (UE) capable of performing carrier aggregation, the method comprising: by the UE:

determining that use of a secondary component carrier (SCC) of the network is currently preferred；

detecting that a first performance metric of a primary component carrier (PCC) of the network does not meet a first performance threshold；

reporting to the network that the first performance metric of the serving cell does not meet the second performance threshold, wherein, in response to the determining that use of a secondary component carrier (SCC) is currently preferred, and further in response to detecting that one or more second performance metrics of the PCC meet respective one or more second performance thresholds, the reporting is delayed until after the UE detecting and reporting to the network that a performance metric of a neighbor cell meets a third performance threshold.
The method of claim 16, further comprising:

delaying the reporting that the first performance metric of the serving cell does not meet the second performance threshold and the reporting that the performance metric of the neighbor cell meets the third performance threshold until after the UE transmitting a false report to the network that the first performance metric of the PCC meets a fourth performance threshold.
The method of claim 16, further comprising:

detecting that the SCC is not currently set up for use by the UE；

wherein delaying the reporting is further in response to the detecting that the SCC is not currently set up for use by the UE.
The method of claim 16, wherein at least one of the first performance metric of the PCC and the performance metric of the neighbor cell comprises at least one of a Reference Signal Received Power (RSRP) measurement, a Reference Signal Received Quality (RSRQ) measurement, and a signal-to-noise ratio (SNR) measurement.
The method of claim 16, wherein determining that use of a SCC is currently preferred comprises determining that current data traffic volume is lower than a data traffic threshold.