WO2017044031A1

WO2017044031A1 - Handling of scheduling request resources during secondary cell activation in carrier aggregation systems

Info

Publication number: WO2017044031A1
Application number: PCT/SE2016/050834
Authority: WO
Inventors: Mattias BERGSTRÖM
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2015-09-09
Filing date: 2016-09-07
Publication date: 2017-03-16

Abstract

Techniques are disclosed according to which a user equipment handles scheduling request resources upon secondary cell activation and deactivation, in a wireless communications network that supports selective activation and deactivation of serving cells for the UE. An example method comprises receiving an activation command for a first serving cell, at a first time, and determining a second time, from which scheduling request resources for the first serving cell are to be considered as valid, based on the first time.

Description

HANDLING OF SCHEDULING REQUEST RESOURCES DURING SECONDARY CELL ACTIVATION IN CARRIER AGGREGATION SYSTEMS

TECHNICAL FIELD

The present invention generally relates to wireless communication networks, and more particularly relates to the handling of resources for scheduling requests, in wireless communication networks that support carrier aggregation.

BACKGROUND

Architecture of the Long Term Evolution (LTE) system for proposed standards is shown in Figure 1, including radio access nodes such as eNodeBs (eNBs), Home eNBs (HeNBs), HeNB gateways (HeNB GW) and evolved packet core nodes such as Mobility Management Entities (MMEs) and serving gateways (S-GW). An SI interface connects HeNBs/eNBs to the MME/S-GW and HeNBs to the HeNB GW, while an X2 interface connects peer eNBs/HeNBs, optionally via an X2 GW.

The management system of such architecture is shown in Figure 2. The node elements (NE), such as eNodeBs, are managed by a domain manager (DM), also referred to as the operation and support system (OSS). A DM may further be managed by a network manager (NM). Two NEs are interfaced by X2, whereas the interface between two DMs is referred to as Itf-P2P. The management system may configure the network elements, as well as receive observations associated to features in the network elements. For example, a DM observes and configures NEs, while an NM observes and configures the DM, as well as an NE via the DM. By means of configuration via the DM, NM and related interfaces, functions over the X2 and SI interfaces can be carried out in a coordinated way throughout the Radio Access Network (RAN), eventually involving the Core Network, i.e. MME and S-GWs.

LTE specifications have been standardized to support Component Carrier (CC) bandwidths up to 20 MHz (which is the maximal LTE Rel-8 carrier bandwidth). Hence, an LTE operation with wider bandwidth than 20 MHz is possible, where the total bandwidth used appears as a number of LTE carriers to an LTE terminal, such as a user equipment or UE. The straightforward way to obtain this would be by means of Carrier Aggregation (CA). CA implies that an LTE Rel-10 terminal can receive multiple CCs, where the CCs may have the same structure as a Rel-8 carrier. In this document, the term component carrier (CC) is used interchangeably with the term serving cell. It will be appreciated that all of the serving cells for a given terminal may or may not originate or terminate at the same base station. As illustrated in Figure 3, the LTE standard supports up to 5 aggregated carriers where each carrier is limited in the Radio Frequency (RF) specifications to have a one of six bandwidths namely 6, 15, 25, 50, 75 or 100 Resource Blocks (RBs) (corresponding to 1.4, 3, 5, 10, 15 and 20 MHz respectively). The number of aggregated CCs, as well as the bandwidth of the individual CCs, may be different for uplink and downlink. A symmetric configuration refers to the case where the number of CCs in downlink and uplink is the same, whereas an asymmetric configuration refers to the case where the number of CCs is different. It is important to note that the number of CCs configured in the network may be different from the number of CCs seen by a UE. That is, a UE may, for example, support more downlink CCs than uplink CCs, even though the network offers the same number of uplink and downlink CCs.

During initial access, an LTE CA-capable UE behaves similar to a UE not capable of CA. Upon successful connection to the network, a UE may, depending on its own capabilities and the network, be configured with additional CCs in the uplink and downlink.

Configuration is based on Resource Radio Control (RRC). Due to the heavy signaling and rather slow speed of RRC signaling, a UE may be configured with multiple CCs even though not all of them are currently used.

A UE is always configured with at least one CC for the uplink and at least one CC for the downlink. One CC in each direction is the primary component carrier, which is interchangeably called the primary cell, or PCell. Additional CCs in either direction are referred to as secondary component carriers, or secondary cells (SCells). If a UE is activated on multiple CCs, this would mean it has to monitor all downlink CCs for Physical Downlink Shared Channel (PDCCH) and Physical Downlink Control Channel (PDSCH). This implies a wider receiver bandwidth, higher sampling rates, etc., resulting in high power consumption.

With SCells, additional bandwidth resources for a given resource can be configured and deconfigured dynamically. However, the configuration/deconfiguration of cells is signaled by the eNB and performed with RRC signaling, which is heavy signaling and slow. Since RRC signaling is heavy and slow, the concept of activation and deactivation was introduced for SCells. The eNB can deactivate those serving cells for a UE that the eNB decides the UE does not need for the moment, which reduces the power consumption at the UE. Similarly, the eNB can quickly activate an already configured SCell for the UE, when it is needed for uplink or downlink traffic.

Activation/deactivation of SCells is performed with Medium Access Control (MAC) signaling, which is faster than RRC signaling. The activation/deactivation procedure is described in detail in section 5.13 of the 3 GPP specification of the MAC protocol for LTE, 3 GPP TS 36.321 v. 12.6.0 (June 2015), available at www.3gpp.org. Each SCell is configured with a SCelllndex, which is an identifier or so called Cell Index that is unique among all serving cells configured for this UE. The PCell will always have Cell Index 0 and the SCell can have an integer cell index of 1 to 7.

The Rel-10 Activation/Deactivation MAC Control Element (CE) is defined in section 6.1.3.8 of the 3GPP document referenced above. The Activation/Deactivation MAC CE consists of a single octet containing seven C-fields and one R-field. Each C-field corresponds to a specific SCelllndex and indicates whether the specific SCell is activated or deactivated. The UE will ignore all C-fields associated with Cell indices not being configured. The Activation/Deactivation MAC CE always indicates the activation status of all configured SCells, meaning that if the eNB wants to activated one SCell, it has to include all configured SCells, setting them to activated or deactivated even if the status has not changed.

If a UE's serving cell is activated, the UE has to monitor PDCCH and PDSCH for that serving cell. This implies that the UE is using a wider receiver bandwidth, higher sampling rates, etc., resulting in high power consumption compared to the scenario where that serving cell is deactivated.

SUMMARY

With the introduction of scheduling request (SR) transmissions on SCells, the UE can send SRs on cells that can be selectively activated/deactivated by the eNB. With this introduction, a problem arises in that it is not clear when, during the activation/deactivation procedures, the UE should consider SR resources "valid." Hence, there is ambiguity as to when the UE can send scheduling requests. Embodiments of the present invention thus include different methods according to which the UE can consider SR resources becoming valid during an activation or deactivation procedure. According to these methods, the UE considers SR resources valid or invalid depending on the stage of the SCell activation or deactivation procedure.

According to a first aspect, a method, in a UE adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE, comprises receiving an activation command for a first serving cell, at a first time, and determining a second time, from which SR resources for the first serving cell are to be considered as valid, based on the first time. According to a second aspect, a method, in a UE adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE, comprises receiving a deactivation command for a first serving cell, at a first time, and determining a second time, from which SR resources for the first serving cell are to be considered as not valid, based on the first time.

According to a third aspect, a method, in a UE adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE, comprises receiving an activation command for a first serving cell, activating the first serving cell, in response to the activation command, and considering scheduling request resources for the first serving cell to be valid upon said activating.

According to some embodiments, a UE is adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE, where the UE is adapted to carry out a method according to any one or more of the above methods.

According to some embodiments, a UE includes a transceiver circuit configured for communication with one or more serving cells in a wireless communications network that supports selective activation and deactivation of serving cells for the UE and a processing circuit configured to control the transceiver circuit. The processing circuit is also configured to receive an activation command for a first serving cell, at a first time and determine a second time, from which scheduling request resources for the first serving cell are to be considered as valid, based on the first time.

According to some embodiments, a UE includes a transceiver circuit configured for communication with one or more serving cells in a wireless communications network that supports selective activation and deactivation of serving cells for the UE and a processing circuit configured to control the transceiver circuit. The processing circuit is also configured to receive an activation command for a first serving cell, activate the first serving cell, in response to the activation command, and consider scheduling request resources for the first serving cell to be valid upon said activating.

According to some embodiments, a UE includes a transceiver circuit configured for communication with one or more serving cells in a wireless communications network that supports selective activation and deactivation of serving cells for the UE and a processing circuit configured to control the transceiver circuit. The processing circuit is also configured to receive a deactivation command for a first serving cell, at a first time, and determine a second time, from which scheduling request resources for the first serving cell are to be considered as not valid, based on the first time.

Other aspects detailed herein include apparatus, computer programs and computer readable medium corresponding to the above-summarized methods. Of course, the present invention is not limited to the above features and advantages. Those of ordinary skill in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a diagram illustrating an LTE architecture showing logical interfaces between eNBs and HeNBs (X2) and between eNB/HeNBs and MME/S-GW (SI).

Figure 2 illustrates an example management system in LTE.

Figure 3 illustrates carrier aggregation.

Figure 4 illustrates an ambiguity period for SR resource validity, in connection with activation of an SCell.

Figure 5 illustrates an ambiguity period for SR resource validity, in connection with deactivation of an SCell.

Figures 6, 7, 8, 9, 10, and 11 illustrate the timing for considering SR resources to be valid and not valid, according to each of several techniques.

Figure 12 is a block diagram of a network access node, according to some

embodiments.

Figure 13 is a block diagram of a user equipment, according to some embodiments. Figures 14, 15, and 16 are flowcharts illustrating methods for handling SR resources, according to some embodiments.

DETAILED DESCRIPTION

SCell activation is subject to delays. In LTE, if a UE receives an

activation/deactivation command for an SCell in a given transmission time interval (TTI), say TTI N, the UE is allowed to activate the SCell at any time between TTI N+8 up to TTI N+24 or N+34. A TTI in LTE is 1 -millisecond long. This allows a good UE implementation to activate the SCell quickly and use the associated radio resources early, while still allowing slower-performing UEs to also operate in the system. Whether 24 or 34 milliseconds applies for the maximum timing for activating an SCell depends on, for example, whether the UE has performed a measurement on the SCell shortly before the activation command. Note that the eNB will, in general not know how much time the UE requires to activate an SCell, so from 8 milliseconds after the UE received the activation command until 24 or 34 milliseconds after the command is received, the UE may have the SCell activated without the eNB knowing.

SCell deactivation is also subject to delays. The UE is allowed some processing time for deactivation of SCells, from the time the deactivation command is received until the SCell is actually deactivated. According to current LTE specifications, this delay is 8 milliseconds.

In LTE, the uplink transmissions by the UE are scheduled by the eNB, and hence the eNB needs to know when the UE is in need of being scheduled. Thus, the concept of scheduling requests (SRs) has been introduced. In LTE, the eNB can provide the UE with SR resources, and the UE can, on these resources, indicate to the eNB that the UE is in need of being scheduled. Release 13 of the 3 GPP standards for LTE introduces the possibility of sending uplink control information on a Physical Uplink Control CHannel (PUCCH) on SCells. With the introduction of PUCCH transmissions on SCells, it will also be possible to send SRs on SCells.

According to current specifications for LTE, the UE counts the number of SRs it has transmitted, and this counter is used to determine when the UE should consider that SR transmissions have failed. Upon SR transmission failure, the UE initiates a random access procedure. This random access procedure may thus be considered a fallback mechanism for failed SR transmissions.

Furthermore, according to current specifications, the UE may only send SRs on an SR resource that is considered to be "valid." If the UE has no valid SR resources, the UE should instead perform a Random Access procedure, during which the UE may be provided with SR resources. However, performing a Random Access procedure may be costly in terms of time and energy. In addition, resources for Random Access procedures are limited, and hence should not be used unnecessarily.

With the introduction of SR transmissions on SCells, the UE can send SRs on cells that can be selectively activated and deactivated by the eNB. With this introduction, a problem arises in that it is not clear when during the activation/deactivation procedures the UE should consider SR resources "valid." Hence, there is an ambiguity as to when the UE can send scheduling requests. The techniques and apparatus detailed below thus include different methods according to which the UE can consider SR resources becoming valid during an activation or deactivation procedure. According to these methods, the UE considers SR resources valid or invalid depending on the stage in an SCell activation or deactivation procedure. Following are detailed descriptions of several methods applied by a terminal, e.g., a LTE UE, for when to consider Physical Uplink Control Channel (PUCCH) resources for SR (or "SR resources," for short) configured for a serving cell to be "valid" and "not valid," in relation to when the associated serving cell becomes activated and deactivated.

Figure 4 illustrates the timing for four embodiments when an SCell is activated. These four embodiments correspond to different times (A, B, C and D) within an ambiguity period. The four embodiments are as follows:

1) the UE considers the SCell' s PUCCH resources for SR transmission valid upon reception of an activation command (time A);

2) the UE considers the SCell' s PUCCH resources for SR transmission valid after a minimum activation delay after the activation command was received (time B);

3) the UE considers the SCell' s PUCCH resources for SR transmission valid after an actual activation delay after the activation command was received (time C); or

4) the UE considers the SCell' s PUCCH resources for SR transmission valid after a maximum activation delay after the activation command was received (time D).

Note that in some embodiments (e.g., A and B), the UE may consider the SR resources for the SCell to be valid even though the cell on which the resources are configured is not yet activated.

Figure 5 illustrates the timing for two embodiments, relative to the receipt of the deactivation command. The two embodiments where the SCell is deactivated are as follows:

1) the UE considers the SCell' s PUCCH resources for SR transmission not valid upon reception of a deactivation command (time X); or

2) the UE considers the SCell 's PUCCH resources for SR transmission not valid after the actual deactivation delay after the deactivation command was received (time Y).

Note that the maximum allowed activation delay is not necessarily the same as the actual deactivation delay.

It can be seen that these two embodiments correspond to the beginning and end of the ambiguity period.

Figures 4 and 5 and much of the discussion herein refer to PUCCH resources for SR transmission being considered valid/invalid at particular times after the UE has received a command activating/deactivating an SCell. It should be understood, that in some

embodiments these times may be relative to a point at which the UE has processed, decoded, or applied the command. Detailed below are the four different embodiments shown in Figure 4 and summarized above, for a UE to apply in determining whether SR resources for an SCell are "valid" or "not valid" during an SCell activation procedure. In a first embodiment, the SR resources for a SCell are considered valid upon reception of the activation command. This is illustrated by time A in Figure 4, as well as in Figure 6, which illustrates the results of this approach. In Figure 6, the SR resources that are not valid are depicted with dashed boxes, while those SR resources that are valid are shown with solid boxes. The UE considers SR resources as valid as soon as it has received the activation command, i.e., beginning at time A. Note that in some cases, the UE may consider the SR resources valid as soon as it has processed, decoded, or applied the command.

Figure 7 illustrates a second, different embodiment for when to consider SR resources for an SCell to be "valid" or "not valid" during an SCell activation procedure. Again, SR resources that are considered not valid are depicted with dashed boxes, while SR resources considered to be valid are shown with solid boxes. The UE considers SR resources as valid after the minimum activation delay has passed (at time B).

According to this embodiment, the UE will consider SR resources valid after a minimum SCell activation delay has passed since the UE received (or processed, decoded, applied) the command activating the SCell. This minimum delay may be 8 milliseconds, in some embodiments, e.g., such that the UE will consider a PUCCH resource for SR for a secondary SCell as valid from N+8 after the UE has received an activation command from the eNB activating the SCell, where N is the TTI in which the activation command was received.

The benefit of this embodiment, as in several other embodiments, is that it is well defined when the UE will begin considering the SR resources as valid. In other words, regardless of how long the actual activation delay is for a UE, the UE will always consider the SR resources valid after a fixed time from the time the activation command is received. The eNB may therefore know when the UE considers the resources valid, and may thus know when the UE starts sending SR, increasing the SR counter, etc.

According to a third embodiment in the case of SCell activation, illustrated in Figure 8, the UE will consider SR resources as valid when the associated SCell has completed activation. According to current specifications, the UE may complete activation up to 24 milliseconds or 34 milliseconds after receiving a command activating the SCell. Again, SR resources that are considered not valid are depicted with dashed boxes, while SR resources that are considered valid are shown with solid boxes. The UE considers SR resources as valid after the UE has completed the activation procedure (at time C).

A benefit of this approach is that the UE may perform SR transmissions as soon as the UE has completed activation of the associated serving cell. However, as different UEs may take different times to activate an SCell, it may result in that different UEs behave differently, which, for example, could complicate testing.

Figure 9 illustrates a fourth embodiment in the case of SCell activation. According to this approach, the UE will consider SR resources to be valid after the maximum allowed activation delay has passed since the UE received the activation command for the serving cell having the SR resources. Once more, SR resources which are not valid are depicted with dashed boxes, while SR resources which are valid are illustrated with solid boxes. The UE considers SR resources as valid after the maximum SCell activation delay has passed (at time D).

Figures 10 and 11 illustrate two different rules or methods that the UE may apply when determining whether SR resources for an SCell are "valid" or "not valid" during an SCell deactivation procedure. According to a first embodiment shown in Figure 10, the UE will consider SR resources not valid upon the UE receiving a command that indicates deactivation of the associated SCell. As seen in the figure, the UE considers SR resources as not valid upon receiving the deactivation command (at time X). A benefit of this embodiment is that the UE considers the SR resources invalid as soon as the command is received. This allows the e B to perform efficient SR resource management. For example, the e B may configure multiple UEs with the same SR resources and ensure that they are not activated at the same time using the same cell. In that case, if the eNB wants to disable a certain SR resource for one UE and enable it for another, then the eNB may deactivate the cell for the UE that should no longer use the SR resources and activate the cell for the UE that should use the SR resources.

In a second embodiment for SCell deactivation, shown in Figure 11, the UE considers SR resources to be not valid beginning at a fixed timing from the point at which the UE has received (or processed, decoded, applied) a command that indicates deactivation of the associated SCell. This is shown at time Y in the figure and may be, for example, 8 milliseconds after the reception of the command. A benefit of this technique, in comparison to the approach shown in Figure 10, is that the UE does not need to react very quickly to a deactivation command, and hence the processing requirements on the UE can be relaxed. According to current LTE specifications, such as 3GPP TS 36.321 vl2.6.0, the UE, or rather a MAC entity in the UE, performs the following in a transmission time interval (TTI) when the UE has a valid SR resource:

- if SR COUNTER < dsr-TransMax:

- increment SR COUNTER by 1 ;

- instruct the physical layer to signal the SR on PUCCH;

- start the sr-ProhibitTimer .

- else:

- notify RRC to release PUCCH/SRS for all serving cells;

- clear any configured downlink assignments and uplink grants;

- initiate a Random Access procedure (see subclause 5.1) on the SpCell and cancel all pending SRs.

In some of the techniques described above, e.g., the techniques illustrated in Figures 6 and 7, the UE may consider an SR resource as valid before the serving cell where the SR resources are configured is actually activated. To deal with this, the UE's behavior upon considering the SR resources to be valid may differ, depending on whether the SCell is activated. In such a scenario, the UE would, for example, perform one set of actions if the UE considers the SR resources valid, but the associated serving cell has not become activated yet, and perform another set of actions if the UE considers the SR resources valid and the associated serving cells has become activated.

In one particular version of this approach, a MAC entity in the UE will, if the SR resources are valid but the serving cell is not yet fully activated, increment SR COUNTER and start the sr-ProhibitTimer (given that SR COUNTER < dsr-TransMax) and it will not instruct the physical layer to signal the SR on PUCCH. An alternative to this is that the MAC entity instructs the physical layer to signal the SR on PUCCH, but the physical layer does not perform the transmission.

In some embodiments, the UE may refrain from initiating a random access procedure due to SR failure during an activation delay time. For example, if the UE has received a command for activating an SCell at time T and the UE at time T+x should transmit an SR but the SR resources are yet not considered valid at time T+x, then the UE may refrain from initiating a random access procedure. The benefit of this is that in this state (at time T+x) the UE may soon have valid SR resources as the associated SCell is soon activated, and as soon as the SR resources become valid then the UE may use these SR resources to transmit an SR to the eNB. The activation delay may likely take a shorter time than the random access procedure would, hence the delay will be shorter by waiting for the SR resources to be valid, compared to triggering a random access procedure.

Figure 12 illustrates a diagram of an example network access node 50, which may be an LTE eNB, for example. The network access node 50 provides an air interface to a wireless device, e.g., an LTE air interface or WLAN air interface for downlink transmission and uplink reception, which is implemented via antennas 54 and a transceiver circuit 56. The transceiver circuit 56 may include transmitter circuits, receiver circuits, and associated control circuits that are collectively configured to transmit and receive signals according to a radio access technology, for the purposes of providing cellular communication or Wi-Fi services, depending on the type of network access node. According to various embodiments, cellular communication services may be operated according to any one or more of the 3 GPP cellular standards, GSM, GPRS, WCDMA, HSDPA, LTE and LTE-Advanced. Wi-Fi services may be operated according to IEEE 802.11 standards, but are not limited to these standards.

The network access node 50 may also include communication interface circuits 58 for communicating with nodes in the core network, other peer radio nodes, and/or other types of nodes in the network. The network access node 50 may be, for example, a base station such as an eNodeB. The network access node 50 may also be, for example, an indoor License Assisted Access (LAA) device or a device for a small cell. For example, the network access node 50 may be an indoor picocell device configured to provide or continue to provide LAA services over unlicensed frequency spectrum to wireless devices within a building, femtocell or picocell. LAA services may be provided to the wireless terminal by a combination of services from a base station and an indoor picocell device. In some embodiments, the network access node 50 may be a wireless local area network (WLAN) access point (AP).

The network access node 50 also includes one or more processing circuits 60 that are operatively associated with the radio transceiver circuit 56. For ease of discussion, the one or more processing circuits 60 are referred to hereafter as "the processing circuit 60". The processing circuit 60 comprises one or more digital processing circuits, e.g., one or more microprocessors, microcontrollers, Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs), Complex Programmable Logic Devices (CPLDs), Application Specific Integrated Circuits (ASICs), or any mix thereof. More generally, the processing circuit 60 may comprise fixed circuitry, or programmable circuitry that is specially adapted via the execution of program instructions implementing the functionality taught herein, or may comprise some mix of fixed and programmed circuitry. The processing circuit 60 may be a multi-core based processing circuit having two or more processor cores utilized for enhanced performance, reduced power consumption, and more efficient simultaneous processing of multiple tasks.

The processing circuit 60 is also associated with memory 70. The memory 70, in some embodiments, stores one or more computer programs 76 and, optionally, configuration data 78. The memory 70 provides non-transitory storage for the computer program 76 and it may comprise one or more types of computer-readable media, such as disk storage, solid- state memory storage, or any mix thereof. By way of non-limiting example, the memory 70 comprises any one or more of SRAM, DRAM, EEPROM, and FLASH memory. In the case of a multi-core processing circuit, a large number of processor cores may share resources, such as memory 70.

In general, the memory 70 comprises one or more types of computer-readable storage media providing non-transitory storage of the computer program and any configuration data used by the network node 50. Here, "non-transitory" means permanent, semi-permanent, or at least temporarily persistent storage and encompasses both long-term storage in non-volatile memory and storage in working memory, e.g., for program execution.

The processing circuit 60 comprises carrier aggregation control circuitry 62 that is configured to, among other things, activate and deactivate serving cells for UEs, e.g., according to individual traffic requirements for the UEs. The carrier aggregation control circuitry 62 is further configured to receive scheduling requests for UEs on serving cells for the UEs, and is still further configured, in some embodiments, to determine when a UE considers scheduling request resources for a given serving cell to be valid or not valid, based upon when an activation command was sent to the UE. Based on this determination, the carrier aggregation control circuitry then knows when the UE may start sending scheduling requests and when the UE begins increasing its scheduling request counter, etc.

Figure 13 illustrates a diagram of a wireless device, such as UE 80, according to some embodiments. To ease explanation, the UE 80 may also be considered to represent any wireless devices that may operate in a wireless communications network that supports the selective activation and deactivation of serving cells for the UE 80. The UE 80 herein can be any type of wireless device capable of communicating with network node or another UE over radio signals. The UE 80 may also be referred to, in various contexts, as a radio

communication device, a target device, a device to device (D2D) UE, a machine type UE or UE capable of machine to machine communication (M2M), a sensor equipped with UE, PDA (personal digital assistant), Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), etc.

The UE 80 communicates with a radio node or base station, such as network access node 50, via antennas 84 and a transceiver circuit 86. The transceiver circuit 86 may include transmitter circuits, receiver circuits, and associated control circuits that are collectively configured to transmit and receive signals according to a radio access technology, for the purposes of utilizing cellular communication services.

The UE 80 also includes one or more processing circuits 82 that are operatively associated with the radio transceiver circuit 86. The processing circuit 82 comprises one or more digital processing circuits, e.g., one or more microprocessors, microcontrollers, DSPs, FPGAs, CPLDs, ASICs, or any mix thereof. More generally, the processing circuit 82 may comprise fixed circuitry, or programmable circuitry that is specially adapted via the execution of program instructions implementing the functionality taught herein, or may comprise some mix of fixed and programmed circuitry. The processing circuit 82 may be multi-core.

The processing circuit 82 also includes a memory 94. The memory 94, in some embodiments, stores one or more computer programs 96 and, optionally, configuration data 98. The memory 94 provides non-transitory storage for the computer program 96 and it may comprise one or more types of computer-readable media, such as disk storage, solid-state memory storage, or any mix thereof. By way of non-limiting example, the memory 94 comprises any one or more of SRAM, DRAM, EEPROM, and FLASH memory, which may be in the processing circuit 82 and/or separate from processing circuit 82. In general, the memory 94 comprises one or more types of computer-readable storage media providing non- transitory storage of the computer program 96 and any configuration data 98 used by the user equipment 80.

The UE 80, in various embodiments, is adapted to carry out any of the UE-based techniques described herein, including those illustrated in Figures 4-11 and in the process flow diagrams of Figures 14-16. For example, the processor 92 of the processor circuit 82 may execute a computer program 96 stored in the memory 94 that configures the processor 92 to receive an activation command for a first serving cell, at a first time, and to determine a second time, from which scheduling request resources for the first serving cell are to be considered as valid, based on the first time. As another example, the processor 92 of the processor circuit 82 may execute a computer program 96 stored in the memory 94 that configures the processor 92 to receive an activation command for a first serving cell, to activate the first serving cell, in response to the activation command; and to consider scheduling request resources for the first serving cell to be valid upon this activating. As still another example, the processor 92 of the processor circuit 82 may execute a computer program 96 stored in the memory 94 that configures the processor 92 to receive a

deactivation command for a first serving cell, at a first time, and to determine a second time, from which scheduling request resources for the first serving cell are to be considered as not valid, based on the first time.

In view of the detailed examples provided above, it will be appreciated that Figure 14 illustrates an example method 1400 in a UE adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE. As shown at block 1410, the method 1400 includes receiving an activation command for a first serving cell, at a first time. In some embodiments, the first time corresponds to one of the following: when the activation command is decoded by the UE; when the activation command is processed by the UE; and when the activation command is applied by the UE. As seen at block 1420, the method 1400 further includes determining a second time, from which scheduling request resources for the first serving cell are to be considered as valid, based on the first time.

In some embodiments, determining the second time comprises considering scheduling request resources for the first serving cell to be valid from the first time. In other

embodiments, determining the second time, from which scheduling request resources for the first serving cell are to be considered as valid, comprises considering scheduling request resources for the first serving cell to be valid beginning at a predetermined interval after the first time. This predetermined interval may correspond to a predetermined minimum activation delay, such as 8 transmission-time intervals, in some embodiments. In some of these embodiments, the method may further comprise determining that the scheduling request resources for the first serving cell for a first transmission-time interval are valid but the first serving cell is not yet activated and, in response, increment a scheduling request counter for the first serving cell but refrain from transmitting a scheduling request in the first

transmission-time interval. This is shown at block 1430 of Figure 14. In some of these or in other embodiments, the method may further comprise determining that there has been a scheduling request failure at a time during which the scheduling request resources for the first serving cell for a first transmission-time interval are valid but the first serving cell is not yet activated and, in response to said determining, refraining from initiating a random access procedure. This is shown at block 1440 of Figure 14. In some embodiments, the predetermined interval referred to above may correspond to a maximum allowed activation delay. This may be 24 or 32 transmission-time intervals, in some embodiments.

Figure 15 illustrates another example method 1500 in a UE adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE. As shown at blocks 1510 and 1520, the method 1500 includes receiving an activation command for a first serving cell and activating the first serving cell, in response to the activation command. As shown at block 1530, the method further includes considering scheduling request resources for the first serving cell to be valid upon said activating.

Figure 16 illustrates an example method 1600 in a UE adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE. As shown at block 1610, the method 1600 includes receiving a deactivation command for a first serving cell, at a first time. In some embodiments, the first time corresponds to one of the following: when the deactivation command is decoded by the UE; when the deactivation command is processed by the UE; and when the deactivation command is applied by the UE. As seen at block 1620, the method 1600 further includes determining a second time, from which scheduling request resources for the first serving cell are to be considered as not valid, based on the first time.

In some embodiments, determining the second time comprises considering scheduling request resources for the first serving cell to be not valid from the first time. In other embodiments, determining the second time, from which scheduling request resources for the first serving cell are to be considered as valid, comprises considering scheduling request resources for the first serving cell to be valid beginning at a predetermined interval after the first time. This predetermined interval may correspond to a predetermined minimum deactivation delay, such as 8 transmission-time intervals, in some embodiments.

The various techniques detailed above, specific examples of which are summarized below, include methods according to which the UE handles SR resources upon SCell activation and deactivation, providing the UE with ways of handling SR transmissions during activation/ deacti vati on procedure s .

Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A method (1400) in a user equipment, UE, (80) adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE (80), the method (1400) comprising:

receiving (1410) an activation command for a first serving cell, at a first time; and determining (1420) a second time, from which scheduling request resources for the first serving cell are to be considered as valid, based on the first time.

2. The method (1400) of claim 1, wherein the first time corresponds to one of the following:

when the activation command is decoded by the UE (80);

when the activation command is processed by the UE (80); and

when the activation command is applied by the UE (80).

3. The method (1400) of claim 1 or 2, wherein determining (1420) the second time, from which scheduling request resources for the first serving cell are to be considered as valid, comprises considering scheduling request resources for the first serving cell to be valid from the first time.

4. The method (1400) of claim 1 or 2, wherein determining (1420) the second time, from which scheduling request resources for the first serving cell are to be considered as valid, comprises considering scheduling request resources for the first serving cell to be valid beginning at a predetermined interval after the first time.

5. The method (1400) of claim 4, wherein the predetermined interval corresponds to a predetermined minimum activation delay.

6. The method (1400) of claim 5, wherein the predetermined minimum activation delay is 8 transmission-time intervals.

7. The method (1400) of any of claims 4-6, further comprising determining that the scheduling request resources for the first serving cell for a first transmission-time interval are valid but the first serving cell is not yet activated and, in response, incrementing a scheduling request counter for the first serving cell but refraining from transmitting a scheduling request in the first transmission-time interval.

8. The method (1400) of any of claims 4-6, further comprising determining that there has been a scheduling request failure at a time during which the scheduling request resources for the first serving cell for a first transmission-time interval are valid but the first serving cell is not yet activated and, in response to said determining, refraining from initiating a random access procedure.

9. The method (1400) of claim 4, wherein the predetermined interval corresponds to a maximum allowed activation delay.

10. The method (1400) of claim 9, wherein the maximum allowed activation delay is 24 or 32 transmission-time intervals.

11. A method (1500) in a user equipment, UE, (80) adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE (80), the method (1500) comprising:

receiving (1510) an activation command for a first serving cell;

activating (1520) the first serving cell, in response to the activation command; and considering (1530) scheduling request resources for the first serving cell to be valid upon said activating (1520).

12. A method (1600) in a user equipment, UE, (80) adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE (80), the method (1600) comprising:

receiving (1610) a deactivation command for a first serving cell, at a first time; and determining (1620) a second time, from which scheduling request resources for the first serving cell are to be considered as not valid, based on the first time.

13. The method (1600) of claim 12, wherein the first time corresponds to one of the following:

when the deactivation command is decoded by the UE (80);

when the deactivation command is processed by the UE (80); and when the deactivation command is applied by the UE (80).

14. The method (1600) of claim 12 or 13, wherein determining (1620) the second time, from which scheduling request resources for the first serving cell are to be considered as not valid, comprises considering scheduling request resources for the first serving cell to be not valid from the first time.

15. The method (1600) of claim 12 or 13, wherein determining (1620) the second time, from which scheduling request resources for the first serving cell are to be considered as not valid, comprises considering scheduling request resources for the first serving cell to be not valid beginning at a predetermined interval after the first time.

16. The method (1600) of claim 15, wherein the predetermined interval corresponds to a predetermined minimum deactivation delay.

17. The method (1600) of claim 16, wherein the predetermined minimum activation delay is 8 transmission-time intervals.

18. A user equipment, UE, (80) adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE (80), wherein the UE (80) is adapted to carry out a method (1400, 1500, 1600) according to any one or more of claims 1-16.

19. A user equipment, UE, (80) comprising:

a transceiver circuit (86) configured for communication with one or more serving cells in a wireless communications network that supports selective activation and deactivation of serving cells for the UE (80); and

a processing circuit (82) configured to control the transceiver circuit (86) and to: receive an activation command for a first serving cell, at a first time; and determine a second time, from which scheduling request resources for the first serving cell are to be considered as valid, based on the first time.

20. The UE (80) of claim 19, wherein the first time corresponds to one of the following: when the activation command is decoded by the UE (80); when the activation command is processed by the UE (80); and

when the activation command is applied by the UE (80).

21. The UE (80) of claim 19 or 20, wherein the processing circuit (82) is configured to determine the second time, from which scheduling request resources for the first serving cell are to be considered as valid, by considering scheduling request resources for the first serving cell to be valid from the first time.

22. The UE (80) of claim 19 or 20, wherein the processing circuit (82) is configured to determine the second time, from which scheduling request resources for the first serving cell are to be considered as valid, by considering scheduling request resources for the first serving cell to be valid beginning at a predetermined interval after the first time.

23. The UE (80) of claim 22, wherein the predetermined interval corresponds to a predetermined minimum activation delay.

24. The UE (80) of claim 23, wherein the predetermined minimum activation delay is 8 transmission-time intervals.

25. The UE (80) of any of claims 22-24, wherein the processing circuit (82) is configured to determine that the scheduling request resources for the first serving cell for a first transmission-time interval are valid but the first serving cell is not yet activated and, in response, increment a scheduling request counter for the first serving cell but refrain from transmitting a scheduling request in the first transmission-time interval.

26. The UE (80) of any of claims 22-24, wherein the processing circuit (82) is configured to determine that there has been a scheduling request failure at a time during which the scheduling request resources for the first serving cell for a first transmission-time interval are valid but the first serving cell is not yet activated and, in response to said determining, refrain from initiating a random access procedure.

27. The UE (80) of claim 22, wherein the predetermined interval corresponds to a maximum allowed activation delay.

28. The UE (80) of claim 27, wherein the maximum allowed activation delay is 24 or 32 transmission-time intervals.

29. A user equipment, UE, (80) comprising:

a processing circuit (82) configured to control the transceiver circuit (86) and to: receive an activation command for a first serving cell;

activate the first serving cell, in response to the activation command; and consider scheduling request resources for the first serving cell to be valid upon said activating.

30. A user equipment, UE, (80) comprising:

a processing circuit (82) configured to control the transceiver circuit (86) and to: receive a deactivation command for a first serving cell, at a first time; and

determine a second time, from which scheduling request resources for the first serving cell are to be considered as not valid, based on the first time.

31. The UE (80) of claim 30, wherein the first time corresponds to one of the following: when the deactivation command is decoded by the UE (80);

when the deactivation command is processed by the UE (80); and

when the deactivation command is applied by the UE (80).

32. The UE (80) of claim 30 or 31, wherein the processing circuit (82) is configured to determine the second time, from which scheduling request resources for the first serving cell are to be considered as not valid, by considering scheduling request resources for the first serving cell to be not valid from the first time.

33. The UE (80) of claim 30 or 31, wherein the processing circuit (82) is configured to determine the second time, from which scheduling request resources for the first serving cell are to be considered as not valid, by considering scheduling request resources for the first serving cell to be not valid beginning at a predetermined interval after the first time.

34. The UE (80) of claim 33, wherein the predetermined interval corresponds to a predetermined minimum deactivation delay.

35. The UE (80) of claim 34, wherein the predetermined minimum activation delay is 8 transmission-time intervals.

36. A computer program (96) comprising instructions that, when executed on a processing circuit (82) of a user equipment, UE, (80) adapted to operate in a wireless communications network that supports selective activation and deactivation of serving cells for the UE (80), cause the UE (80) to carry out a method (1400, 1500, 1600) according to any one of claims 1-16.

37. A carrier containing the computer program (96) of claim 36, wherein the carrier is one of an electronic signal, optical signal, radio signal, or a non-transitory computer-readable storage medium (94).