Control of Bandwidth Portion (BWP) Usage by User Devices

Abstract

A user equipment device (UE) receives scheduling directives from its serving access node that grant the UE an air interface resource and specify a scheduled BWP and a scheduling time slot offset. In response, the UE decides that (i) it will instruct the UE to perform a BWP switch by setting the specified BWP to inactive, and (ii) the specified time slot offset is too low for a BWP switch. In response to making this decision, the UE counts the number of scheduling directives it has received from the access node that specify the respective BWPs and the respective time slot offsets that are too low for a BWP switch, and (b) the UE performs a BWP switch in response to counting a quantity that is at least a predefined threshold quantity of at least 2.

Description

TECHNICAL FIELD

[0001] Reference to related applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 585,470, filed on September 26, 2023, which is hereby incorporated by reference in its entirety into the present specification. BACKGROUND ART

[0002] background A typical wireless communication network includes a plurality of access nodes configured to serve user equipment devices (UEs) such as mobile phones, tracking devices, wireless-enabled personal computers, gaming devices, Internet of Things (IoT) devices, and other wireless-enabled devices.

[0003] Each such access node may include an antenna structure and associated equipment that enables the access node to provide one or more cells that respectively define wireless coverage for serving UEs via respective air interfaces. Further, each access node may be coupled with a core network that includes infrastructure configured to support the access node's service for UEs and that provides connectivity with a transport network such as the Internet. With this configuration, when a UE is located within the coverage of an access node, the UE may be able to perform air interface communication with the access node, thereby enabling the UE to communicate via the access node, the core network, and the transport network that includes various remote servers and / or other entities.

[0004] A representative wireless communication network may operate in accordance with one or more radio access technologies (RATs), which may define the physical structure of the air interface between access nodes and UEs, and may also define associated procedures for handling services for UEs.

[0005] The wireless industry has evolved over the years to define various generations of RATs, and continues to evolve to define new generations of RATs. Recent examples of these RATs include, but are not limited to, (i) "4G" Long-Term Evolution (LTE), which facilitates mobile broadband services using technologies such as orthogonal frequency division multiplexing (OFDM) and multiple input multiple output (MIMO); (ii) "5G NR" (5G New Radio), which may use more scalable OFDM air interfaces and other advanced features to support higher data rates and advanced applications; and (iii) "6G," which may support even higher data rates made possible by utilizing millimeter-wave and terahertz spectra.

[0006] Under such a RAT, an access node may be configured to provide each of its one or more cells on a radio frequency (RF) carrier that defines a downlink channel for carrying communications from the access node to the UE and an uplink channel for carrying communications from the UE to the access node. Each of such carriers, and by extension each of such cells, may be either frequency division duplex (FDD) with separate frequency channels defined for downlink and uplink use, respectively, or time division duplex (TDD) with a single frequency channel multiplexed over time for use between downlink and uplink. Furthermore, each of such frequency channels may be defined as a specific frequency range having a bandwidth that defines the width of the carrier in the RF spectrum, extending from low-end frequencies to high-end frequencies.

[0007] Furthermore, the downlink and uplink channels of each cell served by the access node may be structured in a manner that defines physical air interface resources for carrying both control signaling communications and user plane communications between the access node and the UE. For example, an air interface may be divided into frames, subframes, time slots (slots), and symbol time segments (symbols) over time, and into subcarriers over frequency, to define an array of resource elements so that each occupies its own subcarrier and spans its own symbol time segment. Each resource element may then be served to carry data (user plane or control plane) through modulation of the subcarrier of the resource element by an applicable modulation coding scheme. Furthermore, an air interface may be divided into physical resource blocks (PRBs) over time and channel bandwidth, each PRB may span a specific number of subcarriers in frequency (e.g., 12) and a specific duration in time (e.g., half a time slot). Furthermore, specific resource elements within these PRBs may be reserved for specific uses, such as carrying control signaling or carrying user plane data communications.

[0008] In the downlink, for example, certain resource elements may collectively carry signaling from access nodes, which UEs can measure as a basis for measuring cell coverage strength. Furthermore, other resource elements may collectively define a physical downlink control channel (PDCCH) for carrying downlink control signaling, such as scheduling directives from access nodes to UEs. In addition, other resource elements may collectively define a physical downlink shared channel (PDSCH), and access nodes may schedule the use of the PDSCH on a PRB basis for use in carrying user plane data from access nodes to serving UEs.

[0009] On the other hand, in uplinks, certain resource elements may collaboratively define access channels for carrying access requests from the UE to the access node. Furthermore, other resource elements may collaboratively define physical uplink control channels (PUCCH) to carry various uplink signaling, such as measurement reports and scheduling requests from the UE to the access node. In addition, other resource elements may collaboratively define physical uplink sharing channels (PUSCH), and the access node may schedule the use of PUSCH per PRB to carry user plane data from the serving UE to the access node. [Overview of the project]

[0010] overview A method and system for controlling the use of bandwidth portion (BWP) by UEs served by an access node is disclosed.

[0011] In some respects, what is disclosed is an exemplary method that may be implemented by a UE. The exemplary method includes the UE receiving a scheduling directive from an access node during a scheduling time slot that grants the UE an air interface resource, the scheduling directive specifying (i) the BWP in which the air interface resource is defined, and (ii) a time slot offset that defines how many time slots later in the scheduling time slot the air interface resource will be defined, the time slot offset being at least zero. Furthermore, the exemplary method includes, in response to the UE receiving the scheduling directive, (i) causing the UE to set the specified BWP as inactive, so that the scheduling directive instructs the UE to perform a BWP switch from the UE's currently active BWP to the BWP designated as the UE's active BWP, the exemplary method also includes, in response to the UE receiving the scheduling directive, the UE determining that (ii) the specified time slot offset is too low for a BWP switch. Furthermore, exemplary methods include, in response to at least making a decision, (a) the UE counting a quantity of scheduling directives received from an access node, each specifying a designated BWP and each specifying a time slot offset that is too low for a BWP switch, and (b) the UE performing a BWP switch in response to counting a quantity that is at least a predefined threshold quantity of at least 2.

[0012] In other words, an exemplary UE configured to perform such a method is disclosed. The exemplary UE includes a processor, non-transient data storage, and program instructions, stored in the non-transient data storage and executable by the processor, to cause the UE to perform an action to control the UE's use of a BWP when the UE is served by an access node. The action includes the UE detecting the reception of a scheduling directive from the access node during a scheduling time slot that grants the UE an air interface resource, the scheduling directive specifying (i) a BWP in which the air interface resource is defined, and (ii) a time slot offset that defines how many time slots after the scheduling time slot the air interface resource is defined, the time slot offset being at least zero. Furthermore, the operation includes, in response to detecting the receipt of a scheduling directive, (i) causing the UE to set the specified BWP to inactive, so that the scheduling directive instructs the UE to perform a BWP switch from the UE's currently active BWP to the BWP designated as the UE's active BWP, and the operation includes, in response to detecting the receipt of a scheduling directive, (ii) determining that the specified time slot offset is too low for a BWP switch. Furthermore, the operation includes, in response to at least determining, (a) counting the number of scheduling directives received by the UE from the access node, each specifying the specified BWP and each specifying the time slot offset that is too low for a BWP switch, and (b) performing a BWP switch in response to counting a quantity that is at least a predefined threshold quantity of at least 2.

[0013] In other words, at least one non-temporary computer-readable medium is disclosed that stores program instructions executable by at least one processor of the device in order to cause the device to perform the operations described above.

[0014] These embodiments and other embodiments, advantages, and alternatives will become apparent to those skilled in the art by reading the following detailed description with reference to the accompanying drawings as appropriate. Furthermore, it should be understood that this summary and the description provided below illustrate the present invention as an example only and are not intended to limit it. [Brief explanation of the drawing]

[0015] [Figure 1] This is a simplified block diagram of an exemplary wireless communication system in which various disclosed features can be implemented. [Figure 2] This is a simplified diagram of the air interface configuration. [Figure 3] This is a simplified diagram illustrating an exemplary BWP configuration. [Figure 4] This is an illustrative diagram of the BWP desynchronization problem with a compatible CORESET. [Figure 5] This is an illustrative diagram of a BWP desynchronization problem with an incompatible CORESET. [Figure 6] This is a flowchart illustrating an exemplary method. [Figure 7] Another exemplary method is shown below. [Figure 8] This is a simplified block diagram of an exemplary UE. [Modes for carrying out the invention]

[0016] Detailed explanation For illustrative purposes, this description describes exemplary embodiments in the context of 5G NR. However, it will be understood that the disclosed features may be applicable in the context of other RATs. Furthermore, it will be understood that various embodiments disclosed should not necessarily be construed as preferable or advantageous to other embodiments unless otherwise stated. Moreover, variations are possible from the specific configurations and processes disclosed. For example, various entities, components, connections, operations, and other elements disclosed may be added, omitted, distributed, duplicated, rearranged, reordered, combined, or otherwise modified. Furthermore, it will be understood that various technical operations disclosed may be performed at least in part by one or more processing units programmed to perform the operation or to cause one or more other entities to perform the operation.

[0017] 1. Cellular wireless communication Referring to the drawings described above, Figure 1 is a simplified block diagram of an exemplary wireless communication system in which various disclosed features may be implemented. As shown in Figure 1, the exemplary wireless communication system includes a radio access network (RAN) 100 and a core network 102, which may be operated by and / or for a mobile network operator (MNO), also known as a cellular wireless service provider.

[0018] RAN 100 is shown to include at least one access node 104, which may include an antenna and a cell site modem (neither shown) that enable the access node 104 to serve UEs, such as the representative UE 106, via the air interface 108 in accordance with an agreed RAT. For example, the access node 104 may be a 5G NR next generation Node B (gNB) configured to serve UEs via the 5G NR air interface that defines the aforementioned cell, among other possibilities. The access node 104 may take various forms, such as a macro access node, a small cell access node, or a relay access node.

[0019] The core network 102 may be a 5G Core (5GC) network having a service-based architecture including a user plane subsystem 110 and a control plane subsystem 112, details of which are not shown. For example, in a representative 5GC, the user plane subsystem may include a User Plane Function (UPF) configured to provide user plane connectivity with a packet data transport network 114 to facilitate UE communication with an application server and / or other remote endpoint 118. The control plane subsystem 112 in turn may include various additional control plane functions, such as an Access and Mobility Function (AMF) and a Session Management Function (SMF), which are configured to support, for example, UE authentication, mobility management, and service flow management.

[0020] The example UE 106 may take any of the forms described above, among other possibilities. The UE 106 may be equipped with various components (not shown) such as 5G NR radio, antenna structures, and associated circuitry and logic, to support being served by the access node 104 via the air interface 108.

[0021] When such a UE enters coverage of this exemplary network, the UE can detect cell coverage of access nodes. If the coverage is strong enough, the UE may signal with the access nodes to establish an air interface connection, through which the access nodes may serve the UE within their cell. For example, the UE may perform random access signaling and connection signaling, such as radio resource control (RRC) signaling, with the access nodes to establish an air interface connection (e.g., an RRC connection) between the access nodes and the UE within the cell, so as to transition the UE from idle mode to connected mode.

[0022] If a UE has not yet registered its services with the core network, the UE may further perform registration signaling to register its services. For example, the UE may send a registration request to an access node, which may forward it to the control plane subsystem for processing. The control plane subsystem may then authenticate the UE and then set up one or more quality of service (QoS) flows for the UE to carry user plane traffic to and from it.

[0023] Once the UE has an established air interface connection with the access node and has one or more assigned service flows, the access node can then serve packet data communications to the UE on the downlink and uplink of the access node's cell.

[0024] With respect to downlink, for example, when packet data on the transport network arrives on the core network for transmission to the UE, the data flows to the access node, which may buffer the data while suspending over-the-air transmission of the data to the UE. The access node may then allocate one or more downlink PRBs of the UE's serving cell to transport the data to the UE, and may send a downlink control information (DCI) message to the UE that defines a scheduling directive specifying the allocated downlink PRB(s), and may transmit the data to the UE by modulating the data on the subcarrier of the resource element within the allocated downlink PRB(s).

[0025] On the other hand, with respect to uplinks, when a UE has packet data to transmit over the transport network, the UE may buffer the data in a queue that is pending over-the-air transmission of the data to the access node, and the UE may send a scheduling request to the access node that includes a Buffer Status Report (BSR) indicating the amount of data the UE has buffered for uplink transmission. The access node may then allocate one or more uplink PRBs of the UE's serving cell to carry the data from the UE, and the access node may send a DCI message to the UE specifying the allocated uplink PRB. The UE may then transmit the data to the access node by modulating the data on the subcarriers of the resource elements in the allocated uplink PRB, and the access node may forward the data through the core network for final output onto the transport network.

[0026] As described above, the air interface of an access node cell may define downlink and uplink channels that span separate frequency ranges on the FDD carrier or can be multiplexed over time on a common frequency range on the TDD carrier. Furthermore, the air interface may be divided into time slots over time or into arrays of resource elements over time, both in terms of frequency and time. As described above, a specific resource element on the downlink may define a PDCCH for carrying downlink control signaling, another resource element on the downlink may define a PDSCH for carrying scheduled downlink communications, a specific resource element on the uplink may define a PUCCH for carrying uplink control signaling, and another resource element on the uplink may define a PUSCH for carrying scheduled uplink communications.

[0027] 5G NR supports flexible air interface configurations, where the arrangement, size, and periodicity of some of these channels can be dynamically configured. Therefore, numerous air interface configurations are possible.

[0028] Figure 2 is a simplified diagram of an exemplary air interface configuration showing an FDD arrangement where the downlink and uplink frequency ranges are separate, to help illustrate the operation of each downlink and uplink. In particular, Figure 2 shows exemplary downlink and uplink channels over frequency and time, with frequency on the vertical axis and time on the horizontal axis. The frequency range shown for each of these channels may represent the entire carrier bandwidth in each channel, or only a portion of that carrier bandwidth. Furthermore, in accordance with the above description, each channel is shown divided into time slots over time, with each downlink time slot divided into exemplary PDCCH and PDSCH, and each uplink time slot divided into exemplary PUCCH and PUSCH. In exemplary variations, the arrangement, size, and periodicity of the PDCCH and the PUCCH may differ from those shown and may vary over time, among other possibilities.

[0029] In this air interface configuration or other air interface configurations, each DCI transmitted by the access node to the UE may span a specific set of resource elements on the PDCCH within a given time slot and may include a cyclic redundancy check (CRC) that is masked (scrambled) by an identifier assigned to the UE (e.g., a Cell Radio Network Temporary Identifier (C-RNTI)) so that the UE can identify and read the DCI message. Furthermore, the DCI message may be modulated using four-phase-shifted modulation (QPSK) modulation.

[0030] In practice, a UE may monitor the PDCCH for DCI messages addressed to the UE. In particular, the UE may perform a "blind decoding" process in which it reads various candidate sets of resource elements on the PDCCH for DCI messages masked by the UE's identifier. If the UE finds such a DCI message, it may read the DCI message and proceed as instructed. For example, if a DCI message schedules downlink communication of user plane data to a UE, particularly a downlink PRB, the UE may read the data carried by the PDSCH resource element of the indicated PRB(s) and receive that data. Similarly, if a DCI message schedules uplink communication of user plane data from a UE, particularly an uplink PRB, the UE may send the data at the indicated uplink PRB in the PUSCH.

[0031] Furthermore, the DCI message that the access node sends to the UE may also include a time slot offset value that indicates the time slot (or transmit time interval (TTI)) in which the data communication is scheduled to occur. That is, starting from the time slot in which the DCI message is sent to the UE ("scheduled time slot"), this time slot offset value may be a count of a number of time slots earlier than the time slot in which the data communication is scheduled to occur ("specified time slot"). In the case of downlink scheduling, this offset value may be called "k0", and in the case of uplink communication, this offset value may be called "k2".

[0032] This time slot offset value can be a non-negative integer. For example, to schedule communication within the same time slot in which the DCI message is sent, the access node may specify a time slot offset value of zero in the DCI message. Alternatively, to schedule communication within a time slot four time slots after the scheduling time slot, the access node may specify a time slot offset value of 4 in the DCI message.

[0033] According to this specified time slot offset value on the downlink, the access node then communicates data to the UE within the indicated time slot, and the UE receives the data within that time slot. Similarly, according to the specified time slot offset value on the uplink, the UE then communicates data to the access node within the indicated time slot, and the access node receives the data within that time slot.

[0034] Access nodes and UEs may also perform acknowledgment and retransmission processes to help ensure the successful reception of scheduled data communications. This is typically a hybrid automatic retransmission request (HARQ) process, which involves details for both uplink and downlink transmissions.

[0035] In uplink HARQ, when an access node schedules an uplink transmission from a UE, (i) the access node may include the HARQ process number in its DCI message to the UE; (ii) the access node may then determine whether it has successfully received the scheduled uplink transmission from the UE; and (iii) if the access node has not successfully received the scheduled uplink transmission, the access node may instruct the UE to retransmit the data by sending a new DCI message to the UE specifying the same HARQ process number.

[0036] In downlink HARQ, similarly, when an access node schedules a downlink transmission to a UE, (i) the access node may similarly include the HARQ process number in its DCI message to the UE; (ii) the UE may then determine whether it has successfully received the scheduled downlink transmission from the access node; and (iii) the UE may then send a HARQ acknowledgment or denial to the access node accordingly. If the UE has successfully received the data transmission, it may send an acknowledgment (ACK). On the other hand, if the UE has not successfully received the data transmission, it may send a denial (NACK), in which case the access node may retransmit, sending a new DCI message to the UE similarly specifying the same HARQ process number.

[0037] Furthermore, once the access node serves the UE, the access node and the UE may perform an uplink power control process to help control the transmit power the UE uses for its uplink transmissions to the access node. In an exemplary power control process, the UE may transmit to the access node, and the access node may compare the received strength of that transmission to a defined setpoint. If the received strength is greater than the setpoint, the access node may instruct the UE to reduce its transmit power level. If the received strength is less than the setpoint, the access node may instruct the UE to increase its transmit power level.

[0038] The UE may also have a maximum allowable transmit power level, which may be defined by the UE's power class. As the UE and access node perform the power control process, the UE may also continue to track a “power headroom” value representing the difference between the UE’s currently set transmit power and the UE’s maximum allowable transmit power. Under insufficient RF conditions, the power control process may cause the UE to operate at its maximum transmit power level, at which point the UE has zero power headroom (or, in situations where the UE has received a power-up command while already at its maximum power level, negative power headroom is possible).

[0039] 2. Bandwidth portion (BWP) and associated control resource set (CORESET) Typical RATs, such as, but not limited to, 5G NR, may further utilize a “Bandwidth Portion” (BWP) structure in conjunction with the associated “Control Resource Set” (CORESET) structure to help limit the range over which the UE operates on the UE’s serving carrier, thereby helping to conserve power (e.g., battery power, where applicable) for the UE.

[0040] As its name suggests, BWP defines a portion of a carrier's total bandwidth that may be less than or equal to the entire carrier bandwidth. For a given carrier, distinct BWPs can be defined on the downlink and uplink channels. Furthermore, a given BWP can be defined as a contiguous set of PRBs, starting from a specific PRB within the channel bandwidth and having a BWP bandwidth that spans a certain number of carrier PRBs.

[0041] Next, the downlink BWP includes at least one CORESET that defines the physical resources constituting the PDCCH for carrying downlink control information, such as scheduling directives. The CORESET in a given BWP may be localized to a specific frequency range within the BWP, e.g., a specific set of consecutive PRBs (e.g., a multiple of 6 consecutive PRBs) and a specific number (e.g., 1, 2, or 3) of symbol time segments. Furthermore, a search space may be associated with the CORESET, and the search space may have a specific periodicity (e.g., every slot, every other slot, every 5 slots, etc.) that defines how often the CORESET is repeated.

[0042] In earlier generations of RATs such as LTE, the PDCCH spanned almost the entire downlink carrier bandwidth at the start of each subframe, requiring the UE to perform blind decoding across its entire carrier bandwidth within each subframe to find any DCI messages addressed to the UE. The BWP / CORESET structure provides much greater flexibility in defining the PDCCH, including the fact that it does not need to span the carrier bandwidth. Furthermore, since the new RAT has a much wider carrier bandwidth, this flexibility allows for much more efficient UE decoding of the PDCCH.

[0043] Figure 3 is a simplified diagram of possible BWP configurations. In Part A, the diagram shows examples of BWPs with different bandwidths. Specifically, the diagram shows one BWP spanning a relatively narrow bandwidth, which may be suitable when there is little data to communicate, and another BWP spanning a relatively wide bandwidth, which may be suitable when there is a lot of data to communicate. Furthermore, the diagram shows each of these BWPs with PDCCH defined in all slots. On the other hand, in Part B, Figure 3 shows examples of BWPs with the same bandwidth but with CORESETs defining different PDCCH monitoring periodics. Specifically, the diagram shows one BWP with PDCCH monitoring in all slots, which may be suitable when there is a lot of data to communicate, and another BWP with PDCCH monitoring every other slot, which may be suitable when there is very little data to communicate. Many other configurations may also be possible.

[0044] When a UE is served by an access node on a given carrier, the UE may be configured to operate on multiple different BWPs, which may have different bandwidths and possibly different frequency positions within the carrier bandwidth, and may have different coresets. In particular, the UE may be configured to operate on multiple different downlink BWPs and multiple different uplink BWPs.

[0045] For example, the UE may be provisioned with data defining each downlink BWP, the associated CORESET, and each uplink BWP, where applicable, and the UE may be configured to selectively operate on each of these BWPs by being able to refer to the provisioned data and, accordingly, operating within a given BWP with a given CORESET. Furthermore, each of the UE's BWPs on the carrier's downlink channels and carrier's uplink channels may have its own BWP index that distinguishes the BWP from other BWPs of the UE on that channel.

[0046] In an FDD carrier, the downlink BWP and uplink BWP of a UE can be configured separately. On the other hand, in a TDD carrier, a UE may have downlink-uplink BWP pairs, where the downlink BWP and uplink BWP in each pair have the same BWP index and the same center frequency, but may have different bandwidths.

[0047] In a typical system, for both downlinks and uplinks, the UE always sets only one of its multiple BWPs to "active" and each of the other BWPs to "inactive". For example, if the UE is configured to operate with four downlink BWPs, the UE will always set only one of those downlink BWPs to active and the other three to inactive. Similarly, if the UE is configured to operate with four uplink BWPs, the UE will always set only one of those uplink BWPs to active and the other three to inactive.

[0048] In a TDD carrier, the UE's active downlink BWP and uplink BWP may be linked by a BWP index such that when the UE sets the downlink BWP of a given BWP index as the UE's active downlink BWP, the UE sets the uplink BWP of the same BWP index as the UE's active uplink BWP.

[0049] The UE may store data specifying which of its configured BWPs are active and which are inactive. For example, with respect to downlinks, the UE may store an index of its currently active downlink BWPs, which may establish that each of its other downlink BWPs is inactive. Similarly, with respect to uplinks, the UE may store an index of its currently active uplink BWPs, which may establish that each of its other uplink BWPs is inactive. Alternatively, the UE may be configured to treat a given BWP as either inactive or active in all other cases. The UE may then operate according to this configuration.

[0050] When the UE first signals to connect with the access node, the UE may utilize initial uplink BWPs and initial downlink BWPs defined at least for this purpose. Once the UE is connected to the access node, the access node may then configure several BWPs for the UE that may be activated and used. For example, the access node may send one or more RRC connection reconfiguration messages to the UE carrying data defining each of the various BWPs, including their respective BWP indices, which the UE may read and store the indicated BWP definitions. This data may also designate one of the UE's downlink BWPs as a default BWP that may be applied after a period of inactivity.

[0051] Furthermore, the access node may also store a list of these BWPs that the UE is configured to use, and the UE and access node each store instructions on which of the UE's BWPs are active and which are inactive, so that the UE and access node can communicate with each other over a common BWP (downlink and uplink, respectively).

[0052] In this configuration, when an access node sends a DCI message to the UE to schedule data communication on a downlink or uplink, the access node specifies in the DCI message which BWP will be used to carry the scheduled data communication. To do this, the access node may include a BWP indicator in the DCI message that specifies the BWP index of the BWP that will carry the communication.

[0053] If there is no change in which of the UE's BWPs is active, the UE's initial uplink BWP and initial downlink BWP may be the UE's active BWPs. However, occasionally there may be a change in which of the UE's BWPs (on the downlink and / or uplink) is active. The act of changing which of the UE's BWPs is active is known as a BWP switch.

[0054] Three exemplary mechanisms for BWP switching are (i) a BWP inactive timer, (ii) RRC messaging, and (iii) DCI messaging.

[0055] The BWP inactivity timer may trigger a switch to the UE's default downlink BWP in response to the absence of any communication from the access node to the UE on the UE's currently active BWP during the monitored inactivity period. Under normal operation, when this inactivity timer expires, the UE and access node may update their records to indicate that the UE's default downlink BWP is now active, allowing subsequent DCI messaging from the access node to the UE on that default downlink BWP. Additionally, RRC messaging from the access node to the UE may instruct the UE to switch from activating one of its configured BWPs to activating another of its BWPs, and the UE and access node may update their records accordingly so that they can then communicate with each other on the newly active BWP.

[0056] DCI-based BWP switching involves the access node specifying, as a BWP indicator value in a DCI message to the UE, one of the configured BWPs of the UE that the UE has not currently set as its active BWP. In particular, this specification in the DCI message for a BWP that is not the UE's currently active BWP serves to notify the UE of a BWP switch to the specified BWP. Once the access node instructs the UE to perform this BWP switch, the UE and the access node can also update their records to indicate that the specified BWP is now the UE's active BWP, so that the UE and the access node can then communicate with each other on the newly active BWP.

[0057] Therefore, if a UE is configured as a set of downlink BWPs {BWP-1, BWP-2, BWP-3, and BWP-4}, and if the UE sets downlink BWP-1 as the UE's active downlink BWP, the access node may send a DCI message to the UE in the defined CORESET of BWP-1 to schedule downlink communication to the UE in BWP-2, which is one of the UE's different downlink BWPs. The DCI message not only schedules downlink communication to take place in BWP-2, but also has the effect of triggering a downlink BWP switch of the UE to BWP-2 (and, if applicable, a corresponding uplink BWP switch if TDD is used). Thus, the UE and the access node may update their records to indicate that the UE's newly active downlink BWP is BWP-2, and the DCI message to the UE will be sent on BWP-2 until further BWP switches.

[0058] When a UE performs a BWP switchover, it may need to readjust its RF circuitry and / or perform other processing to switch to the newly active BWP. To assist with this, or for other reasons, UEs and access nodes may be configured to require a minimum "blank period" as a time slot offset after a DCI message indicates a BWP switchover. This minimum blank period may be a number of time slots within the range of 3 to 5 time slots, but is not limited to this.

[0059] For example, the minimum blank period could be 5 time slots. In this example, if the UE has downlink BWP-1 as its active downlink BWP, and the access node instructs the UE to switch downlink BWP from BWP-1 to BWP-2 by sending a DCI message to the UE within a scheduled time slot on BWP-1 to schedule downlink data communication to or from the UE on BWP-2, the access node must specify a time slot offset value of at least 5 (e.g., k0) to specify when the downlink communication will take place. If the access node specifies a time slot offset value of 5, it means that the scheduled downlink data transmission to the UE on the newly active BWP-2 will take place 5 time slots after the scheduled time slot. Thus, within that specified time slot, the access node will send data to the UE on BWP-2, and the UE will receive the transmission.

[0060] In this policy requiring a minimum blank interval, if an access node sends a DCI message to the UE instructing a BWP switchover, and in that DCI message the access node specifies a time slot offset value that is too low (i.e., specifying communication time slots that are not at least the minimum number of time slots requested after the scheduled time slots), the UE may detect this as a policy violation and completely ignore the DCI message. In that situation, the UE may therefore not perform the instructed BWP switchover and may retain its currently active BWP, i.e., the old BWP, instead of switching to the new BWP. Furthermore, the UE may, accordingly, not perform the scheduled data communications.

[0061] 3. Technical issues: BWP synchronization failure However, there is a real problem that can occur with BWP switching: for some reason, the UE may not be able to detect the DCI message sent by the access node instructing the UE to perform a BWP switch. For example, due to noise and / or other issues on the air interface, or possibly issues with the access node or UE, the UE may not receive the DCI message that the access node sends to the UE instructing a BWP switch. (Failure to receive the DCI message can occur if the DCI message does not reach the UE, or if the DCI message reaches the UE but the UE is unable to properly or correctly decode and understand the DCI message.)

[0062] When this happens, the access node might expect a BWP switch to occur as instructed, from the old BWP (e.g., BWP-1) to the new BWP (e.g., BWP-2). However, the UE does not perform such a BWP switch because it has not received a DCI message instructing it to do so. As a result, both the UE and the access node become out of sync with the BWP.

[0063] This BWP (Broadcaster Programming) desynchronization can cause a variety of problems.

[0064] A single BWP out-of-sync issue can occur when a CORESET defined in a new BWP is compatible with a CORESET defined in an old BWP. Because CORESETs can be defined at various frequency positions, with varying periods, bandwidths, and search spaces, and because BWPs can be defined in various bandwidths within the carrier bandwidth, a CORESET defined in one BWP may be compatible with a CORESET defined in another BWP, as their time and frequency may overlap. If a CORESET defined in a new BWP is compatible with a CORESET defined in an old BWP, the UE may still receive the DCI that the access node sends to the UE in the new BWP's CORESET, even though the UE missed the DCI that instructed the BWP switch from the old BWP to the new BWP, because the UE may have received that DCI in the overlapping CORESET of the old BWP.

[0065] In this compatible CORESET scenario, a potential problem that can occur after the UE fails to receive a DCI instructing it to switch from the old BWP to the new BWP is that the UE may ignore the later received DCI message because it might perceive the later received DCI message as violating the BWP switch time slot offset policy.

[0066] In particular, a DCI message instructing a BWP switch from the old BWP to the new BWP may specify an appropriate time slot offset value that provides the expected or requested blanking interval to accommodate the BWP switch, but in this example, the UE does not receive that DCI message. After that blanking interval, the access node assumes that the BWP switch has occurred and then schedules data communication, but may send a DCI message to the UE on the new BWP that does not include the minimum blanking interval time slot offset value, since the DCI message was not intended to instruct a BWP switch. On the other hand, since the UE did not receive a directive to switch to the new BWP, the UE operates on the old BWP which is set as the UE's active BWP.

[0067] Given the CORESET compatibility between the new and old BWPs in this example, the UE monitors the CORESET of the old BWP, and therefore the UE may detect a DCI message sent by the access node on the new BWP's CORESET. However, the UE may (i) recognize that the DCI message specifies the new BWP, in which case it may understand that this constitutes a BWP switch directive since the UE currently has the old BWP as its active BWP; and the UE may further (ii) recognize that the time slot offset value in the DCI message is too low for that BWP switch because it does not allow the requested minimum blank interval. For these reasons, the UE may ignore the DCI. This means that scheduled data communication will not occur, so a HARQ retransmission may occur, and the access node will send a new DCI attempting to reschedule the communication. Furthermore, this HARQ retransmission may be repeated multiple times, placing an inefficient load on air interface resources and potentially degrading the user experience where applicable.

[0068] Figure 4 illustrates an example of this problem across an exemplary series of time slots 1–10 on the downlink. This example shows a scenario where the UE currently has BWP-0 active, the access node instructs a BWP switch to BWP-1, the minimum blank period is k0=5, and the CORESETs of BWP-0 and BWP-1 are compatible with each other.

[0069] In the example in Figure 4, in slot 1, the access node sends a DCI to the UE on the UE's active BWP-0, specifying k0=0, and consequently scheduling downlink communication on BWP-0 in slot 1. The UE successfully receives the DCI and, accordingly, receives the scheduled downlink communication on BWP-0 in slot 1.

[0070] In slot 3, the access node then sends a DCI to the UE that triggers a BWP switchover on the UE's active BWP-0. Specifically, this DCI on BWP-0 schedules k0=5, and therefore downlink communication on BWP-1 in slot 8. The designation of BWP-1 in this DCI corresponds to a BWP switchover instruction because the UE's active BWP is not currently BWP-1, and the designation of k0=5 in this DCI satisfies the minimum blank interval requirement for BWP switching. However, as shown in Figure 4, the UE misses this DCI. That is, the UE does not properly receive this DCI sent in slot 3. Therefore, from the UE's perspective, the UE's active BWP at slot 8 is still BWP-0, but from the access node's perspective, the UE's active BWP at slot 8 is BWP-1.

[0071] In slot 9, the access node then sends a DCI on BWP-1 to the UE, which the access node recognizes as the UE's active BWP. This DCI schedules k0=0, and consequently, downlink communication on BWP-1 in slot 9. For CORESET compatibility, even if the access node sends this DCI on a BWP that the UE has not set as active, the UE will receive this DCI on BWP-0, which is the UE's active BWP. However, from the UE's perspective, the DCI instructs a BWP switch from BWP-0 to BWP-1, but because it specifies a scheduling offset below the minimum blank interval of k0=5, the UE considers this DCI invalid upon receiving it. Therefore, the UE may ignore this DCI, fail to receive the downlink communication scheduled in slot 9, leading to HARQ retransmissions and related inefficiencies.

[0072] Furthermore, this problem can be repeated in slot 10, as shown in the diagram. Specifically, in slot 10, the access node may send a DCI on BWP-1 to the UE, which would schedule k0=0 and thus downlink communication on BWP-1 in slot 10. For CORESET compatibility, the UE may receive this DCI on BWP-0, which is the UE's active BWP. However, the UE may also ignore this DCI, instructing a BWP switch but specifying an insufficient scheduling offset, which could lead to HARQ retransmissions.

[0073] If the CORESET defined in a new BWP is incompatible with the CORESET defined in an old BWP, other BWP desynchronization issues may occur. Specifically, the CORESET defined in a new BWP may be incompatible with the CORESET defined in an old BWP because the time and frequency may not overlap. In this case, the UE is monitoring the incompatible CORESET of the old BWP, and therefore cannot receive the DCI that the access node sends to the UE with the CORESET of the new BWP.

[0074] A potential problem in this incompatible CORESET scenario is that after failing to receive a DCI instructing the UE to switch from the old BWP to the new BWP, the UE may not receive one or more subsequent DCI messages sent from the access node. That is, after instructing the BWP switch and after a blank interval, the access node may send a new DCI message to the UE on the new BWP to schedule data communication. However, because the UE is operating on the old BWP due to the incompatible CORESET, the UE does not receive that new DCI message. Therefore, newly scheduled data communication between the access node and the UE fails, resulting in HARQ retransmissions, which are associated with inefficiencies and, where applicable, can degrade the user experience.

[0075] Figure 5 illustrates an example of this problem, similarly across an exemplary series of time slots 1–10 on the downlink. This example shows a scenario where the UE currently has BWP-0 active, the access node instructs a BWP switch to BWP-1, the minimum blank period is k0=5, but the CORESETs of BWP-0 and BWP-1 are incompatible with each other.

[0076] In the example in Figure 5, in slot 1, the access node sends a DCI on the UE's active BWP-0 to the UE, which means k0=0 and schedules downlink communication on BWP-0 in slot 1. The UE successfully receives the DCI and, accordingly, receives the scheduled downlink communication on BWP-0 in slot 1. Furthermore, in slot 2, the access node sends a DCI on the UE's active BWP-0 to the UE, which means k0=0 and schedules downlink communication on BWP-0 in slot 2. The UE successfully receives the DCI and, accordingly, receives the scheduled downlink communication on BWP-0 in slot 2.

[0077] In slot 3, the access node then sends a DCI to the UE that triggers a BWP switchover on the UE's active BWP-0. Specifically, this DCI on BWP-0 schedules k0=5, and therefore downlink communication on BWP-1 in slot 8. Similar to the example above, the specification of BWP-1 in this DCI corresponds to a BWP switchover instruction because the UE's active BWP is not currently BWP-1, and the specification of k0=5 in this DCI satisfies the minimum blank interval requirement for BWP switching. However, as shown in Figure 4, the UE misses this DCI again. That is, the UE does not properly receive this DCI sent in slot 3. Therefore, from the UE's perspective, the UE's active BWP at slot 8 is still BWP-0, but from the access node's perspective, the UE's active BWP at slot 8 is BWP-1.

[0078] In this example, in slot 9, the access node then sends a DCI on BWP-1 to the UE, recognizing the access node as the UE's active BWP. This DCI schedules k0=0, and consequently, downlink communication on BWP-1 in slot 9. However, as shown in the diagram, due to CORESET incompatibility, the UE does not receive this DCI. Therefore, the UE does not receive the downlink communication scheduled in slot 9, leading to HARQ retransmission and potentially resulting in inefficiencies.

[0079] Furthermore, this problem can be repeated in slot 10, as shown in the diagram. That is, in slot 10, the access node may send a DCI on BWP-1 to the UE, which means k0=0 and thus schedules downlink communication on BWP-1 in slot 10. Again, due to CORESET incompatibility, the UE does not receive this DCI, as shown in the diagram, and therefore does not receive the downlink communication scheduled in slot 10, similarly leading to HARQ retransmission.

[0080] 4. Technical solutions for BWP synchronization issues with compatible CORESET According to this disclosure, the UE can perform processes to help overcome BWP desynchronization situations with compatible CORESETs. In particular, the UE may be able to overcome this problem by keeping track of the number of DCI messages it receives that appear to indicate a BWP switch, but each provides an insufficient time slot interval for the BWP switch, and when the UE detects at least a predefined threshold number (the threshold number is at least 2) of such non-compliant DCI messages, the UE may, in response, perform the indicated BWP switch.

[0081] More specifically, when a UE receives a DCI message from its serving access node within a scheduled time slot, and the UE finds that the DCI message specifies (i) a BWP that the UE has currently set to inactive (e.g., a BWP that the UE has not set to active) and (ii) a time slot offset shorter than the minimum blank interval threshold after the scheduled time slot, the UE starts a counter to count the number of such non-compliant DCI messages that it receives successively (in sequence, not necessarily in consecutive time slots) from the access node.

[0082] This counter may begin with the most recently received non-compliant DCI message, and the UE may increment the counter each time it receives another DCI message from the access node for scheduled communication that specifies the UE's inactive BWP (e.g., the same inactive BWP as the UE) and a time slot offset shorter than the minimum blank interval threshold. (Alternatively, the counter may begin with the next non-compliant DCI message received, among other possibilities.) The access node may repeatedly send such DCIs to the UE to facilitate retransmission, for example, in a HARQ process or other scenario. Thus, each time the UE receives the next such non-compliant DCI message (without receiving a compliant DCI message in between that specifies either the UE's active BWP or an inactive BWP with a sufficiently long time slot interval), the UE may increment its counter for the non-compliant DCI message.

[0083] The UE can then continue to track the level of this counter. When it determines that this counter has reached a predefined threshold level (which may be set to a value between 2 and 10, possibly 3), the UE may respond to the high threshold count of such a non-compliant message by performing a BWP switch, even though the UE's normal process might ignore such a non-compliant message. For example, in response to a high threshold count of a received DCI message specifying an inactive BWP and insufficient time slot intervals for the UE, the UE may reconfigure itself to make the inactive BWP the UE's active BWP. That is, the UE may switch from the old BWP to the new BWP in response.

[0084] This switchover may, after a sufficient waiting period, allow the UE to successfully receive and respond to a DCI message specifying the new BWP. For example, if the access node then sends a DCI message to the UE scheduling communication on the new BWP, the UE can successfully perform that scheduled communication.

[0085] In an embodiment of this solution, the UE may perform this process only if it has not initially received a DCI message from the access node during a blank interval of time. In particular, the UE can detect that at least a number of time slots equal to its blank interval threshold have elapsed without the UE receiving a DCI message from the access node, and that the UE subsequently begins receiving non-compliant DCI messages from the access node. This embodiment considers that, if it is likely that a DCI message has been missed, the access node sets the time slot interval to at least its blank interval period before sending the next DCI message to the UE.

[0086] Furthermore, it should be noted that in this scenario, DCI may be scheduling downlink communication or uplink communication. Additionally, DCIs counted by the UE may or may not be for the same data communication.

[0087] Therefore, Figure 6 is a flowchart illustrating an exemplary method for controlling the use of BWP by UEs served by access nodes.

[0088] As shown in Figure 6, in block 600, an exemplary method includes the UE receiving a scheduling directive from an access node during a scheduling time slot that grants the UE an air interface resource, the scheduling directive specifying (i) the BWP in which the air interface resource is defined, and (ii) a time slot offset that defines how many time slots after the scheduling time slot the air interface resource is defined, the time slot offset being at least zero. In block 602, the exemplary method then includes the UE, in response to receiving the scheduling directive, (i) causing the UE to set the specified BWP to inactive, meaning the scheduling directive instructs the UE to perform a BWP switch from the UE's currently active BWP to the BWP designated as the UE's active BWP, and (ii) the UE determining that the specified time slot offset is too low for a BWP switch. Furthermore, in block 604, an exemplary method includes, in response to at least making a decision, (a) the UE counting a quantity of scheduling directives that the UE receives from an access node, each specifying a designated BWP and each specifying a time slot offset that is too low for a BWP switch, and (b) the UE performing a BWP switch in response to the UE counting a quantity (e.g., a quantity from 2 to 10, among other possibilities) that is at least a predefined threshold quantity that is at least 2.

[0089] In accordance with the above description, the act of the UE determining that a specified time slot offset is too low for a BWP switchover may include the UE determining that the specified time slot offset is less than a predefined threshold number of time slots, in some cases the threshold is set to a number of time slots between 3 and 5, among other possibilities.

[0090] Furthermore, as described above, the act of the UE determining that the specified time slot offset is too low for a BWP switchover may also include the UE determining that, prior to the scheduling time slot, the UE did not receive any scheduling directives from the access node within a predefined threshold number of time slots.

[0091] In addition, as described above, the act of the UE receiving scheduling directives from the access node may follow after the UE fails to detect an earlier scheduling directive from the access node that specifies a designated BWP and a time slot offset that is greater than or equal to a predefined threshold number of time slots. For example, this process may follow after the UE misses receiving a DCI message instructing a BWP switchover, which could put the UE and the access node into a BWP out-of-sync state.

[0092] Furthermore, as described above, the act of counting the number of scheduling directives that the UE receives from the access node, specifying the respective BWPs and the respective time slot offsets that are too low for BWP switching, may also include the UE counting the number of scheduling directives that the UE successively receives from the access node, without the UE receiving any intermediary scheduling directives from the access node that specify the UE's currently active BWP.

[0093] From another perspective, what is disclosed is an exemplary UE including a processor, non-temporary data storage, and program instructions, stored in the non-temporary data storage and executable by the processor, to cause the UE to perform actions to control the UE's use of BWP when the UE is served by an access node. Here, the actions may follow those described above with respect to the exemplary method, among other possibilities.

[0094] Furthermore, it should be noted that the exemplary UE may also include a wireless communication interface, and the process may be part of that wireless communication interface. For example, the UE may include a chipset designed to perform cellular wireless communication according to a defined RAT, and the chipset may include a processor that executes instructions for performing these operations. Alternatively, or further, the UE's host processor may, where applicable, interact with the UE's wireless communication interface to perform some or all of these operations.

[0095] From yet another perspective, what is disclosed is an exemplary non-temporary computer-readable medium containing instructions executable by a processor, which, when the UE is served by an access node, causes the UE to perform actions to control the UE's use of the BWP. Here, the actions may also follow those described above with respect to exemplary methods, among other possibilities.

[0096] 5. Technical solutions for BWP synchronization issues with incompatible CORESET. Furthermore, according to this disclosure, the UE can perform processes to help overcome BWP desynchronization situations with incompatible CORESETs. In particular, the UE may help overcome this problem by detecting when the UE has not received a DCI from the access node during a threshold time period and, accordingly, testing one or more of the other configured BWPs of the UE in an attempt to find a potentially functional BWP, i.e., a BWP that the access node considers to be the UE's currently active BWP.

[0097] In this solution, the UE can first detect if it has not received a DCI message from the access node for at least a threshold time period. This threshold time period may be predefined by the engineering design and, in some cases, may be set long enough to be considered problematic. Alternatively, this threshold time period may be predefined in real time based on the context. For example, if the UE sends a scheduling request message to the access node to elicit an uplink scheduling grant, in response, the UE may expect to receive a DCI message from the access node scheduling its uplink communication within the threshold time period. Thus, the UE can treat that threshold time period as the threshold time period for detecting the non-reception of the DCI message from the access node. Or, if the UE is performing certain types of communication in which it may expect to receive a downlink scheduling grant at a certain period or other criterion, that expectation may similarly define the threshold time period for the UE to detect the non-reception of the DCI message from the access node. An example of this threshold time period could be around 2 to 50 frames, among other possibilities.

[0098] In response to detecting that the UE has not received DCI messages from the access node for at least a threshold time period, the UE may then test one or more of its inactive BWPs to determine whether one of those BWPs is functional, i.e., on the grounds that the access node may have instructed a switch to that BWP and the UE may have missed the directive to switch to that BWP. For example, the UE may test each of its inactive BWPs in turn to see if it is functional until it finds a functional BWP, at which point the UE may reconfigure itself to make one of them the UE's currently active BWP. Alternatively, the UE may test only one of its inactive BWPs, and if it finds that it is functional, it may reconfigure itself to make that BWP the active BWP.

[0099] While not limited to this, this testing process may work particularly well on TDD carriers where each of the UE's downlink BWPs is bound to an uplink BWP of the same BWP index. In this scenario, to test one of the UE's inactive BWPs to see if it works, the UE may send a scheduling request to an access node on the inactive uplink BWP, and the UE may wait for a threshold time period to see if the UE receives a DCI providing an uplink scheduling grant in response from the access node on the corresponding inactive downlink BWP.

[0100] If the UE receives a DCI from the access node providing an uplink scheduling grant upon the expiration of this threshold time period, the UE can reasonably conclude that the inactive BWP (uplink and downlink) is a BWP that the access node considers to be the UE's active BWP. Therefore, the UE may perform a BWP switch to make that inactive BWP the UE's new active BWP. On the other hand, if the UE does not receive a DCI from the access node providing an uplink scheduling grant upon the expiration of this threshold time period, the UE can reasonably conclude that the inactive BWP being tested is not a BWP that the access node considers to be the UE's active BWP. Therefore, the UE may proceed with testing one of the UE's next inactive BWPs as needed.

[0101] This test process can also work for FDD carriers where the UE's uplink BWP and downlink BWP are in different frequency bands. In this scenario, the UE may test an inactive uplink BWP to determine whether scheduling requests on that inactive uplink BWP will result in the UE receiving DCI messages from the access node on the UE's active downlink BWP. If this test fails (i.e., the UE does not receive DCI messages in response), the UE may then move on to testing an inactive downlink BWP to determine whether scheduling requests on the UE's active uplink BWP will result in the UE receiving DCI messages from the access node on the inactive downlink BWP. Ultimately, the UE may, by means of or otherwise, sequentially test various uplink-downlink combinations of the UE's configured uplink BWP and its configured downlink BWP until it finds a working combination. Once a working combination is found, the UE may switch that combination to be the UE's active combination of uplink BWP and downlink BWP.

[0102] In this process, the scheduling requests that the UE on the BWP under test sends to the access node may be pseudo-scheduling requests, meaning they do not have to correspond to the uplink data that the UE has buffered for transmission. One way to do this is for the UE to include a non-zero, nominal BSR in the scheduling request. For example, even if the UE may have a large amount of data buffered for transmission, or even if the UE may not have any data buffered for transmission, the UE may include a BSR in the scheduling request specifying a very small amount of data for testing purposes. Alternatively, especially if the UE is buffering data for transmission, a successful test would allow the UE to move on to uplink transmission of that data on the new BWP, and thus the UE could send an actual scheduling request.

[0103] In embodiments of this solution, the UE may perform this process only if it has at least a predefined threshold minimum level of power headroom, which can establish that there are no power limitations on the UE and that the UE can, at least theoretically, successfully send scheduling requests to the access node. For example, the UE may perform this process only if it is not currently operating at its maximum transmit power level (which may be zero power headroom, or even worse, negative power headroom), and possibly in response to detecting that the UE has not received DCI messages from the access node for at least a threshold time period.

[0104] Therefore, Figure 7 is another flowchart illustrating another exemplary method for controlling the use of BWP by the UE served by the access node.

[0105] As shown in Figure 7, in block 700, the exemplary method includes the UE detecting that a predefined threshold time amount has elapsed since the UE last received an air interface scheduling directive from the access node. In block 702, the exemplary method then includes the UE testing to determine whether the UE receives the relevant scheduling directive from the access node as a result of a scheduling request sent from the UE to the access node within the UE's inactive BWP, at least in response to the detection. Furthermore, in block 704, the exemplary method includes reconfiguring the UE to transition the inactive BWP to the UE's active BWP in response to this test establishing that the UE receives the relevant scheduling directive from the access node as a result of a scheduling request sent from the UE to the access node within the UE's inactive BWP.

[0106] As described above, the act of the UE detecting that a predefined threshold time has elapsed since it last received an air interface scheduling directive from an access node may include the UE detecting that a predefined threshold time has elapsed since it sent a first uplink scheduling request (i.e., such a given uplink scheduling request) to the access node, and that the UE has not received an uplink scheduling grant from the access node in response to that first uplink scheduling request.

[0107] As further explained above, the act of the UE testing to determine whether the UE will receive the relevant scheduling directive from the access node as a result of a scheduling request sent from the UE to the access node within the UE's inactive BWP may include the UE sending a scheduling request within the inactive BWP and then the UE determining whether it will receive the relevant scheduling directive from the access node in response to the sent scheduling request.

[0108] Furthermore, as described above, a UE may have multiple inactive BWPs, including a first inactive BWP and including the aforementioned inactive BWP as a second inactive BWP. In this case, the method may include, in response to the UE detecting that a predefined threshold time has elapsed since the UE last received an air interface scheduling directive from an access node, (i) the UE first tests to determine whether the UE receives a first relevant scheduling directive from an access node as a result of a scheduling request sent from the UE to the access node within the first inactive BWP; and (ii) in response to this first test establishing that the UE did not receive a first relevant scheduling directive from an access node as a result of a scheduling request sent from the UE to the access node within the first inactive BWP, the UE then tests to determine whether the UE receives a second relevant scheduling directive from an access node as a result of a scheduling request sent from the UE to the access node within the second inactive BWP.

[0109] Furthermore, as described above, in the exemplary embodiment, the UE may perform this exemplary method only if the UE has a power headroom at least a non-zero level of a predefined threshold, i.e., a power headroom that indicates that the UE's uplink transmit power is set to a level lower than the UE's maximum allowable uplink transmit power.

[0110] Furthermore, as mentioned above, scheduling requests sent by the UE in this manner may be fake scheduling requests that are not based on uplink data buffered by the UE.

[0111] Furthermore, as mentioned above, this process can work well in TDD scenarios where the UE's inactive BWP is defined by the TDD carrier. However, the process can also work in FDD scenarios, in which case a variant of the method may be applied, which may involve testing various combinations of the UE's uplink and downlink BWP until one works.

[0112] Disclosed for this solution is an exemplary UE, which includes a processor, non-temporary data storage, and program instructions, stored in the non-temporary data storage and executable by the processor, to cause the UE to perform actions to control the UE's use of BWP when the UE is served by an access node. Similarly, the operation may follow those described above with respect to the exemplary method, among other possibilities.

[0113] Furthermore, this exemplary UE may also include a wireless communication interface, and the process may be part of that wireless communication interface. For example, the UE may include a chipset designed to perform cellular wireless communication according to a defined RAT, and the chipset may include a processor that executes instructions for performing these operations. Alternatively, or further, the UE's host processor may, where applicable, interact with the UE's wireless communication interface to perform some or all of these operations.

[0114] Furthermore, disclosed in relation to this solution is an exemplary non-temporary computer-readable medium storing instructions executable by the processor, the instructions causing the UE to perform actions to control the UE's use of the BWP when the UE is served by the access node. Here, the actions may also follow those described above with respect to the exemplary method, among other possibilities.

[0115] 6. Exemplary UE and related structures Figure 8 is a simplified block diagram of an exemplary UE, showing some of the components that the exemplary UE may include. As shown, the UE may include a wireless communication interface 800, a processor 802, and non-temporary data storage 804. These components can be integrated with each other in various ways and / or linked to communicate with each other. For example, the components may be linked with each other via a system bus, network, or other connection mechanism 806. Alternatively, various integrations and other configurations are possible. For example, the processor 802 may be a component of the wireless communication interface 800.

[0116] The wireless communication interface 800 may include one or more modules (e.g., one or more chipsets) configured to facilitate wireless communication between the UE and the access node according to one or more RATs, such as 4G LTE, 5G NR, and / or one or more other protocols. As shown in the figure, for example, the wireless communication interface 202 may include one or more radios 808, one or more amplifiers 810, and one or more antennas 812. One or more radios 808 may include one or more radio transmitters configured to modulate a baseband signal to a radio frequency RF carrier, and one or more radio receivers configured to demodulate a baseband signal from one or more RF carriers. One or more amplifiers 810 may be configured to amplify an oscillating signal for transmission and / or a received signal for processing. And one or more antennas 812 may be configured to transmit and / or receive RF signals. The wireless communication interface 800 may further include various circuits and / or other logic to facilitate operation according to one or more RATs.

[0117] The processor 802 may include one or more general-purpose processors (e.g., one or more microprocessors) and / or one or more dedicated processors (e.g., digital signal processors, application-specific integrated circuits). Furthermore, the non-temporary data storage 804 may include one or more volatile and / or non-volatile storage components (e.g., optical, magnetic, or flash storage, RAM, ROM, EPROM, EEPROM, cache memory, and / or other computer-readable media) which may be integrated all or partly into the processor 802. As shown in the figure, the non-temporary data storage 804 may store program instructions 814 which may be executable by the processor 802 to perform the various operations described herein. Furthermore, the non-temporary data storage 804 may store reference data 816, such as BWP configuration data, among other possibilities.

[0118] The various features described herein can be implemented in this context, and vice versa.

[0119] Furthermore, this disclosure also intends to include non-temporary computer-readable media (e.g., optical, magnetic, or flash storage, RAM, ROM, EPROM, EEPROM, etc.) that store program instructions executable by the processor of the UE in order to cause the UE to perform various operations described herein, including various operations of the exemplary methods described above.

[0120] Exemplary embodiments are described above. However, those skilled in the art will understand that these embodiments may be modified and altered without departing from the true scope and spirit of the invention.

Claims

1. A method for controlling the use of a bandwidth portion (BWP) by user equipment devices (UEs) served by an access node, the method being: The method includes the UE receiving a scheduling directive from the access node during a scheduling time slot that grants the UE an air interface resource, the scheduling directive specifying (i) a BWP in which the air interface resource is defined, and (ii) a time slot offset that defines how many time slots after the scheduling time slot the air interface resource is defined, wherein the time slot offset is at least zero, and the method further includes In response to receiving the scheduling directive, the method includes (i) the UE deciding to set the designated BWP as inactive, so that the scheduling directive instructs the UE to perform a BWP switch from the UE's currently active BWP to the designated BWP as the UE's active BWP, and the method further includes, in response to receiving the scheduling directive, (ii) the UE deciding that the designated time slot offset is too low for the BWP switch. A method comprising, at least in response to making the above determination, (a) the UE counting a number of scheduling directives received by the UE from the access node, each specifying the designated BWP and each specifying a time slot offset that is too low for the BWP switch; and (b) the UE performing the BWP switch in response to the UE counting a number that is at least a predefined threshold number of at least 2.

2. The method according to claim 1, wherein the UE determines that the specified time slot offset is too low for the BWP switching, the UE determines that the specified time slot offset is less than a predefined threshold number of time slots.

3. The method according to claim 2, wherein the number of time slots with a predefined threshold is between 3 and 5.

4. The method according to claim 2, wherein the determination further includes determining that, prior to the scheduling time slot, the UE did not receive any scheduling directives from the access node within the predefined threshold number of time slots.

5. The method according to claim 2, wherein the UE receiving the scheduling directive from the access node follows the UE's failure to detect an earlier scheduling directive from the access node that specifies the designated BWP and a time slot offset that was greater than or equal to the number of time slots specified in the predefined threshold.

6. The method according to claim 1, wherein the predefined threshold quantity is a quantity between 2 and 10.

7. The method according to claim 1, wherein counting the number of scheduling directives received by the UE from the access node, each specifying the designated BWP, and each specifying a time slot offset that is too low for the BWP switching, includes counting the number of scheduling directives that the UE successively receives from the access node, without the UE receiving any intermediary scheduling directives from the access node that specify the UE's currently active BWP.

8. User equipment (UE), Processor and Non-temporary data storage and When the UE is served by an access node, the UE performs an action to control the use of the bandwidth portion (BWP) by the UE, including program instructions stored in the non-temporary data storage and executable by the processor, the action being performed The operation includes the UE detecting the receipt of a scheduling directive from the access node during a scheduling time slot that grants the UE an air interface resource, wherein the scheduling directive specifies (i) a BWP in which the air interface resource is defined, and (ii) a time slot offset defining how many time slots after the scheduling time slot the air interface resource is defined, the time slot offset being at least zero, and the operation further includes In response to the detection of the reception of the scheduling directive, the operation includes (i) causing the UE to set the designated BWP to inactive, so that the scheduling directive instructs the UE to perform a BWP switch from the UE's currently active BWP to the designated BWP as the UE's active BWP, and the operation further includes, in response to the detection of the reception of the scheduling directive, (ii) determining that the designated time slot offset is too low for the BWP switch. A UE that, in response to at least making the above determination, includes (a) counting a quantity of scheduling directives received by the UE from the access node, each specifying the designated BWP and each specifying a time slot offset that is too low for the BWP switch, and (b) performing the BWP switch in response to counting the quantity, which is at least a predefined threshold quantity of at least 2.

9. The UE according to claim 8, wherein determining that the specified time slot offset is too low for the BWP switching includes determining that the specified time slot offset is less than a predefined threshold number of time slots.

10. The UE according to claim 9, wherein the number of time slots with a predefined threshold is between 3 and 5.

11. The UE according to claim 9, wherein the determination further includes determining that, prior to the scheduling time slot, the UE did not receive any scheduling directives from the access node within the predefined threshold number of time slots.

12. The UE according to claim 9, wherein the UE receiving the scheduling directive from the access node follows the UE's failure to detect an earlier scheduling directive from the access node that specifies the designated BWP and a time slot offset that was greater than or equal to the number of time slots specified in the predefined threshold.

13. The UE according to claim 8, wherein the predefined threshold quantity is between 2 and 10.

14. The UE according to claim 8, wherein counting the number of scheduling directives received by the UE from the access node, each specifying the designated BWP and each specifying a time slot offset that is too low for the BWP switching, includes counting the number of scheduling directives that the UE successively receives from the access node, without the UE receiving any intermediary scheduling directives from the access node that specify the UE's currently active BWP.

15. The UE according to claim 8, further comprising a wireless communication interface, wherein the processor is part of the wireless communication interface.

16. A non-temporary computer-readable medium for storing instructions executable by a processor, wherein the instructions cause a user equipment device (UE) to perform an action to control the use of a bandwidth portion (BWP) by the UE when the UE is served by an access node, and the action is: The operation includes the UE detecting the receipt of a scheduling directive from the access node during a scheduling time slot that grants the UE an air interface resource, wherein the scheduling directive specifies (i) a BWP in which the air interface resource is defined, and (ii) a time slot offset defining how many time slots after the scheduling time slot the air interface resource is defined, the time slot offset being at least zero, and the operation further includes In response to the detection of the reception of the scheduling directive, the operation includes (i) causing the UE to set the designated BWP to inactive, so that the scheduling directive instructs the UE to perform a BWP switch from the UE's currently active BWP to the designated BWP as the UE's active BWP, and the operation further includes, in response to the detection of the reception of the scheduling directive, (ii) determining that the designated time slot offset is too low for the BWP switch. A non-temporary computer-readable medium comprising, at least in response to making the above determination, (a) counting a quantity of scheduling directives that the UE receives from the access node, each specifying the designated BWP and each specifying a time slot offset that is too low for the BWP switch, and (b) performing the BWP switch in response to counting the quantity, which is at least a predefined threshold quantity of at least 2.

17. The non-temporary computer-readable medium according to claim 16, wherein determining that the specified time slot offset is too low for the BWP switching includes determining that the specified time slot offset is less than a predefined threshold number of time slots.

18. The non-temporary computer-readable medium according to claim 17, further comprising determining that, prior to the scheduling time slot, the UE did not receive any scheduling directives from the access node within the predefined threshold number of time slots.

19. The non-temporary computer-readable medium according to claim 17, wherein the UE receives the scheduling directive from the access node after the UE fails to detect an earlier scheduling directive from the access node that specifies the designated BWP and a time slot offset that is greater than or equal to the number of time slots specified in the predefined threshold.

20. The non-temporary computer-readable medium according to claim 16, wherein counting the number of scheduling directives received by the UE from the access node, each specifying the designated BWP, and each specifying the time slot offset that is too low for the BWP switching, includes counting the number of scheduling directives that the UE successively receives from the access node, without the UE receiving any intermediary scheduling directives from the access node that specify the UE's currently active BWP.

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