Apparatuses and methods for CQI reporting for a multi-carrier single cell

Abstract

Example embodiments provide a channel quality reporting procedure enhanced with group-based channel quality reporting for multiple carriers in a Multiple Carrier Single Cell. Apparatuses, methods, and computer programs are disclosed.

Description

APPARATUSES AND METHODS FOR CQI REPORTING FOR A MULTI-CARRIER SINGLE CELLTECHNICAL FIELD

[0001] The present application generally relates to information technology. Some example embodiments of the present application relate to providing an enhanced framework for channel quality reporting for a multi-carrier single cell (MCSC).BACKGROUND

[0002] An MCSC is a single cell in the frequency band of a communications network that has a resource pool of many non-contiguous and collocated frequency carriers. Tight time synchronization and integration of scheduling operations is assumed for the single cell. The MCSC aims to reduce system overhead and enable more flexible radio resource utilization by using multiple narrow carriers combined into a single wideband cell. In contrast, in related carrier aggregation (CA) systems, one carrier is associated with one cell, so overhead and system complexity scales with cell number in such systems.SUMMARY

[0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0004] Example embodiments may increase spectral efficiency and enable user equipment (UE) energy savings by reducing reporting overhead by using an MCSC-specific channel quality reporting configuration. This may be achieved by the features of the independent claims. Further implementation forms are provided in the dependent claims, the description, and the drawings.

[0005] According to a first aspect, an apparatus is provided. The apparatus is, for example, a user equipment (UE). The apparatus may comprise at least one processor; and at leastone memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the apparatus at least to receive, from a network node providing a cell with plural carriers, configuration information indicating plural configurations for channel quality reporting, wherein at least one of the plural configurations is a configuration associated with a channel reporting group, CRG, that comprises at least some carriers of the plural carriers; obtain measurement values for the configuration associated with the CRG based on the received configuration information and based on channel measurements over a bandwidth of the CRG; and transmit channel quality reporting for the CRG based on the obtained measurement values for the configuration associated with the CRG.

[0006] According to an example embodiment of the first aspect, the plural configurations of channel quality reporting include a first configuration that is the configuration associated with the CRG; a second configuration associated with a difference between the channel measurements over the bandwidth of the CRG and channel measurements over a bandwidth of one of the plural carriers of the CRG; and a third configuration associated with measurements over a sub-band of the one of the plural carriers of the CRG.

[0007] According to an example embodiment of the first aspect, the channel quality reporting comprises at least one of (i) channel quality index, CQI, reporting; (ii) reference signal received power, RSRP, reporting; or (iii) signal to interference plus noise ratio, SINR, reporting. According to an example embodiment of the first aspect, the configuration information comprises: (i) offset values for the channel quality reporting; and (ii) parameters for the apparatus to select one of the plural configurations of channel quality reporting.

[0008] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: transmit, to the network node, assistance information indicating that the apparatus supports the configuration associated with the CRG, wherein the assistance information further indicates at least one of: (i) the plural carriers of the CRG; or (ii) differential offset values for the channel quality reporting based on channel measurements of the plural carriers of the CRG.

[0009] According to an example embodiment of the first aspect, the assistance information is UE Assistance Information, and the assistance information indicates MCSC-specific channel quality reporting capabilities of the UE.

[0010] According to an example embodiment of the first aspect, the assistance information indicates the plural carriers of the CRG.

[0011] According to an example embodiment of the first aspect, the assistance information indicates the differential offset values for the channel quality reporting based on channel measurements of the plural carriers of the CRG.

[0012] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: determine the assistance information based on measurements on the plural carriers of the CRG

[0013] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: select the configuration associated with the CRG based on measurements on the plural carriers of the CRG.

[0014] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: select the configuration associated with the CRG when a variance among the channel measurements of the plural carriers of the CRG is below a threshold; and transmit, to the network node, an indication that the configuration associated with the CRG is selected by the apparatus.

[0015] According to an example embodiment of the first aspect, the indication is transmitted to the network node in a channel quality report or a medium access control, MAC, control element, CE.

[0016] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: receive a confirmation in response to the indication, wherein the confirmation is transmitted in a MAC CE.

[0017] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to select the configuration associated with the CRG based on the received configuration information and based on channel measurements on the CRG.

[0018] According to an example embodiment of the first aspect, the parameters for the apparatus to select one of the plural configurations of channel quality reporting include parameters for selecting or switching to the configuration associated with the CRG.

[0019] According to an example embodiment of the first aspect, the first configuration is associated with measurement over a bandwidth of the CRG.

[0020] According to an example embodiment of the first aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: transmit, to a network node, a channel quality report or LI measurement report; and receive, from the network node, an indication of a selected one of the plural configurations for channel quality reporting, where the indication is received in a MAC CE.

[0021] According to an example embodiment of the first aspect, the received indication further indicates a reconfiguration of the CRG.

[0022] According to a second aspect, an apparatus is provided. The apparatus is, for example, a network node. The apparatus may comprise at least one processor; and at least one memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the apparatus at least to transmit, to a user equipment, UE, configuration information indicating plural configurations for channel quality reporting, including a configuration associated with a channel reporting group, CRG, that comprises plural carriers; and receive, from the UE, channel quality reporting for the CRG based on obtained channel measurements over a bandwidth of the CRG for the configuration associated with the CRG.

[0023] According to an example embodiment of the second aspect, the plural configurations of channel quality reporting include a first configuration that is the configuration associated with the CRG, a second configuration associated with a difference between the channel measurements over the bandwidth of the CRG and channel measurements over a bandwidth of one of the plural carriers of the CRG, and a third configuration associated with measurements over a sub-band of the one of the plural carriers of the CRG.

[0024] According to an example embodiment of the second aspect, the channel quality reporting comprises at least one of (i) channel quality index, CQI, reporting; (ii) reference signal received power, RSRP, reporting; or (iii) signal to interference plus noise ratio, SINR, reporting. According to an example embodiment of the second aspect, the at least one memory and thecomputer program code are configured to, with the at least one processor, cause the apparatus to: receive, from the UE, an indication that the configuration associated with the CRG is selected by the UE; and transmit, to the UE, a confirmation in response to the indication, wherein the confirmation is transmitted in a MAC CE.

[0025] According to an example embodiment of the second aspect, indication that the configuration associated with the CRG is selected by the UE is received in a MAC CE.

[0026] According to an example embodiment of the second aspect, the transmitted indication further indicates a reconfiguration of the CRG.

[0027] According to an example embodiment of the second aspect, the first configuration is associated with measurement over a bandwidth of the CRG.

[0028] According to an example embodiment of the second aspect, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: receive, from the UE, a channel quality report or LI measurement report; select, based on the received channel quality report or LI measurement report, one of the plural configurations for channel quality reporting; and transmit, to the UE, an indication of the selected one of the plural configurations for channel quality reporting, wherein the indication is transmitted in a MAC CE.

[0029] According to an example embodiment of the second aspect, the transmitted indication further indicates a reconfiguration of the CRG.

[0030] According to a third aspect, a method may comprise receiving, by a user equipment, UE, from a network node, configuration information indicating plural configurations for channel quality reporting, including a configuration associated with a channel reporting group, CRG, that comprises plural carriers; obtaining, by the UE, measurement values for the configuration associated with the CRG based on the received configuration information and based on channel measurements over a bandwidth of the CRG; and transmitting, by the UE, channel quality reporting for the CRG based on the obtained measurement values for the configuration associated with the CRG.

[0031] According to an example embodiment of the third aspect, the plural configurations of channel quality reporting include a first configuration that is the configuration associated with the CRG; a second configuration associated with a difference between the channel measurements over the bandwidth of the CRG and channel measurements over a bandwidth of one of the pluralcarriers of the CRG; and a third configuration associated with measurements over a sub-band of the one of the plural carriers of the CRG.

[0032] According to an example embodiment of the third aspect, the channel quality reporting comprises at least one of (i) channel quality index, CQI, reporting; (ii) reference signal received power, RSRP, reporting; or (iii) signal to interference plus noise ratio, SINR, reporting. According to an example embodiment of the third aspect, the configuration information comprises: (i) offset values for the channel quality reporting; and (ii) parameters for the apparatus to select one of the plural configurations of channel quality reporting.

[0033] According to an example embodiment of the third aspect, the method comprises transmitting, to the network node, assistance information indicating that the apparatus supports the configuration associated with the CRG, where the assistance information further indicates at least one of: (i) the plural carriers of the CRG; or (ii) differential offset values for the channel quality reporting based on channel measurements of the plural carriers of the CRG.

[0034] According to an example embodiment of the third aspect, the assistance information is UE Assistance Information, and the assistance information indicates MCSC-specific channel quality reporting capabilities of the UE.

[0035] According to an example embodiment of the third aspect, the assistance information indicates the plural carriers of the CRG.

[0036] According to an example embodiment of the third aspect, the assistance information indicates the differential offset values for the CQI reporting based on channel measurements of the plural carriers of the CRG.

[0037] According to an example embodiment of the third aspect, the method comprises determining the assistance information based on measurements on the plural carriers of the CRG.

[0038] According to an example embodiment of the third aspect, the method comprises selecting the configuration associated with the CRG based on measurements on the plural carriers of the CRG.

[0039] According to an example embodiment of the third aspect, the method comprises selecting the configuration associated with the CRG when a variance among the channel measurements of the plural carriers of the CRG is below a threshold; and transmitting, to the network node, an indication that the configuration associated with the CRG is selected by the apparatus.

[0040] According to an example embodiment of the third aspect, the indication is transmitted to the network node in a channel quality report or a medium access control, MAC, control element, CE.

[0041] According to an example embodiment of the third aspect, the method comprises receiving a confirmation in response to the indication, wherein the confirmation is transmitted in a MAC CE.

[0042] According to an example embodiment of the third aspect, the method comprises selecting the configuration associated with the CRG based on the received configuration information and based on channel measurements on the CRG.

[0043] According to an example embodiment of the third aspect, the parameters for the apparatus to select one of the plural configurations of channel quality reporting include parameters for selecting or switching to the configuration associated with the CRG.

[0044] According to an example embodiment of the third aspect, the first configuration is associated with measurement over a bandwidth of the CRG.

[0045] According to an example embodiment of the third aspect, the method comprises transmitting, to a network node, a channel quality report or LI measurement report; and receiving, from the network node, an indication of a selected one of the plural configuration for channel quality reporting, where the indication is received in a MAC CE.

[0046] According to an example embodiment of the third aspect, the received indication further indicates a reconfiguration of the CRG.

[0047] According to a fourth aspect, a method may comprise transmitting, to a user equipment, UE by a network node, configuration information indicating plural configurations for channel quality reporting, including a configuration associated with a channel reporting group, CRG, that comprises plural carriers; and receiving, from the UE in a network node, channel quality reporting for the CRG based on obtained channel measurements over a bandwidth of the CRG for the configuration associated with the CRG.

[0048] According to an example embodiment of the fourth aspect, the plural configurations of channel quality reporting include a first configuration that is the configuration associated with the CRG, a second configuration associated with a difference between the channel measurements over the bandwidth of the CRG and channel measurements over abandwidth of one of the plural carriers of the CRG, and a third configuration associated with measurements over a sub-band of the one of the plural carriers of the CRG.

[0049] According to an example embodiment of the fourth aspect, the channel quality reporting comprises at least one of (i) channel quality index, CQI, reporting; (ii) reference signal received power, RSRP, reporting; or (iii) signal to interference plus noise ratio, SINR, reporting. According to an example embodiment of the fourth aspect, the method may comprise receiving, from the UE, an indication that the configuration associated with the CRG is selected by the UE; and transmitting, to the UE, a confirmation in response to the indication, wherein the confirmation is transmitted in a MAC CE.

[0050] According to an example embodiment of the fourth aspect, indication that the configuration associated with the CRG is selected by the UE is received in a MAC CE.

[0051] According to an example embodiment of the fourth aspect, the transmitted indication further indicates a reconfiguration of the CRG.

[0052] According to an example embodiment of the fourth aspect, the first configuration is associated with measurement over a bandwidth of the CRG.

[0053] According to an example embodiment of the fourth aspect, the method may comprise receiving, from the UE, a channel quality report or LI measurement report; select, based on the received channel quality report or LI measurement report, one of the plural configurations for channel quality reporting; and transmitting, to the UE, an indication of the selected one of the plural configurations for channel quality reporting, where the indication is transmitted in a MAC CE.

[0054] According to an example embodiment of the fourth aspect, the transmitted indication further indicates a reconfiguration of the CRG.

[0055] According to a fifth aspect, an apparatus may comprise means for performing the method of the third or fourth aspect. The apparatus may further comprise means for performing any example embodiment of the method of the third or fourth aspect, as provided in the description and / or the claims.

[0056] According to sixth aspect, a computer program, a computer program product, or a (non-transitory) computer-readable medium is disclosed. The computer program, computer program product, or (non-transitory) computer-readable medium may comprise instructions for causing an apparatus to perform at least the method according to the third or fourth aspect. Thecomputer program may further comprise instructions for causing the apparatus to perform any example embodiment(s) thereof, as provided in the description and / or the claims.

[0057] Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings.DESCRIPTION OF THE DRAWINGS

[0058] The accompanying drawings, which are included to provide a further understanding of the example embodiments and constitute a part of this specification, illustrate example embodiments and together with the description help to explain the example embodiments. In the drawings:

[0059] FIG. 1 illustrates an example of a multi-carrier single cell (MCSC) of a communication network according to an example embodiment.

[0060] FIG. 2 illustrates an example of switching procedure of the UE from an MCSC-specific channel quality reporting configuration according to an example embodiment.

[0061] FIG. 3 illustrates an example of a 3 -stage channel quality feedback scheme according to an example embodiment.

[0062] FIG. 4 illustrates an example of a 3 -stage channel quality reporting scheme for an MCSC cell with five carriers forming a CRG according to an example embodiment.

[0063] FIG. 5 illustrates an example of a channel quality reporting configuration switching mechanism at the UE according to an example embodiment.

[0064] FIG. 6 illustrates an example of a channel quality reporting configuration switching mechanism at the network according to an example embodiment.

[0065] FIG. 7 illustrates an example of an in-band switching indication from UE for a 3-stage channel quality reporting for MCSC according to an example embodiment.

[0066] FIG. 8 illustrates an example of an out-of-band switching indication from the UE for channel quality reporting for MCSC according to an example embodiment.

[0067] FIG. 9 illustrates an example of an apparatus configured to practice one or more example embodiments;

[0068] FIG. 10 illustrates an example of a channel quality reporting method in a communication network according to an example embodiment;

[0069] FIG. 11 illustrates a second example of a channel quality reporting method in a communication network according to an example embodiment;

[0070] Like references are used to designate like parts in the accompanying drawings.DETAILED DESCRIPTION

[0071] Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings. The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present examples may be constructed or utilized. The description sets forth the functions of the example and a possible sequence of operations for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

[0072] FIG. 1 illustrates an example of a multi-carrier single cell (MCSC) of a communication network according to an example embodiment. MCSC is a single frequency cell that has a resource pool of many non-contiguous, and collocated frequency carriers. Tight time synchronization and integration of scheduling operations in baseband may be needed for the single cell.

[0073] Generally, in carrier aggregation, one carrier is associated with one cell; as such, complexity and overhead with respect to the physical layer and radio resource control scales with the number of cells. Accordingly, carrier aggregation is associated with excessive configuration signaling and related latency. Use of the MCSC aims to reduce system overhead and implement more flexible radio resource utilization by using multiple narrow carriers combined into a single wideband cell.

[0074] In an MCSC, multiple component carriers (CCs) are used for a cell, both in uplink (UL) and downlink (DL), where all CCs are co-located at the same network node (e.g., gNB) and assumed to share the same radio frequency, as shown in FIG. 1. The component carriers (CCs) on line 102 in FIG. 1 represent general carrier aggregation, in which each carrier is a separate cell, resulting in many cells.

[0075] On line 104 of FIG. 1, four multi-carrier single cells (MCSCs) are shown to illustrate the difference between the large number of cells using general carrier aggregation on line 102. Furthermore, the CCs of Cell 1 are shown, numbered #1, #2, and #3, as well as labeled with corresponding frequency values. The wideband configurations of the four MCSCs shown in FIG. 1 is an example only - various other MCSC configurations are possible. The CCs of an MCSC may have contiguous or non-contiguous frequencies.

[0076] In this way, us of the MCSC allows fast carrier activation / deactivation within a cell, enables joint RRC configuration and level 1 / level 3 (L1 / L3) processing, and enhances Hybrid Automatic Repeat Request (HARQ) operation to avoid time division duplex (TDD) latency that may arise under general carrier aggregation. Moreover, carriers within an MCSC can be grouped based on key suitability criteria. For example, carriers having similar radio channel properties may be grouped together, where examples of radio channel properties may be channel flatness probability, Doppler shift, Doppler spread, delay spread, and average channel delay.

[0077] Other suitability criteria for grouping carriers within an MCSC may include network ability to maintain transmissions across the grouped carriers with tight time and frequency synchronization. For example, one carrier in the MCSC can serve as a reference carrier transmitting a synchronization signal block (SSB) for coarse synchronization, while the other carriers in the MCSC can send only timing reference signals (TRS) for fine tuning.

[0078] Additionally, carriers grouped in an MCSC can be suited to adapt to different cell coverage ranges and / or have similar timing advance values. Grouped carriers in an MCSC can be controlled by a single radio unit and share hardware components resulting in network energy savings. The network may be configured to choose the number of carriers grouped in an MCSC to facilitate Cross Carrier Scheduling (CCS).

[0079] Because the grouping of carriers within an MCSC multiple carriers may be based on similar spatial and radio channel conditions, this similarity may be leveraged to reduce reporting overhead associated with channel quality measurement and reporting. The reduction in reporting overhead would allow for higher spectral efficiency along with UE energy savings.

[0080] On the other hand, an MCSC-specific channel quality reporting configuration may not be efficient under certain channel conditions, e.g., when the different grouped carriers are measured with different radio conditions. Therefore, a flexible framework which allows forminimized reporting overhead when in adequate radio conditions and larger overhead reporting otherwise would be beneficial.

[0081] Generally, the goal of MCSC-specific frameworks is to reduce overheads associated with the configuration of the multiple carriers within the single cell of the MCSC. The present disclosure is directed to a method of leveraging the similarities in propagation characteristics of carriers grouped in a MCSC to maximize spectral efficiency and aid in UE battery life conservation.

[0082] The disclosed method is implemented in a wireless communication network operated based on a protocol stack comprising a plurality of protocol layers. Example components of the protocol stack comprise layer 1, LI, layer 2, L2, and layer 3, L3, that manage communication between the UE and the network in the wireless communication system. LI, also referred to as the Physical Layer, is responsible for the physical transmission and reception of signals over the air interface, covering processes such as modulation, coding, and signal propagation. L2, or the Data Link Layer, ensures reliable data transfer across the physical link established by LI and includes sub-layers like the Medium Access Control (MAC) layer, the Radio Link Control (RLC) layer, and the Packet Data Convergence Protocol (PDCP) layer.

[0083] The disclosed method includes L2 procedures to allow a network having an MCSC to configure a UE with multiple channel quality reporting configurations. Among the multiple channel quality reporting configurations can be one or more MCSC-specific channel quality reporting configurations, while others can be non-MCSC-specific reporting configurations.

[0084] Furthermore, the present disclosure describes switching procedures to allow the network and the UE to switch from a current channel quality reporting configuration to another channel quality reporting configuration, if switching criteria are satisfied. For example, certain switching criteria may indicate that a current non-MCSC-specific channel quality reporting configuration should be switched to an MCSC-specific channel quality reporting configuration (e.g., a target channel quality reporting configuration), or vice versa.

[0085] For example, the UE may determine that, for a configured MCSC, coarse reporting of the MCSC channel quality is appropriate, based on the UE’s mobility patterns (e.g. stationary), minimum differences in propagation characteristics of the carriers of the MCSC, and the traffic type. To configure and switch between the various channel quality reporting configurations, new messaging protocols are described herein between the UE and the network.

[0086] These are described below with reference to FIG. 2. FIG. 2 shows a message sequence chart 200, which illustrates an example where the UE is configured with multiple CQI reporting configurations and a switch from an MCSC-specific channel quality reporting to a non-MCSC-specific reporting configuration is triggered by the UE. While FIG. 2 and other examples described herein are directed to CQI reporting, the present disclosure may be applied to other channel quality reporting methods, including reference signal received power (RSRP) reporting, signal to interference plus noise ratio (SINK) reporting, and the like.

[0087] Initially, in operation 206 of FIG. 2, a UE 202 communicates in RRC connected mode with a network using an MCSC 204. In the example of FIG 2, the MCSC 204 includes three carriers: reference carrier 1, carrier 2, and carrier 3. The number of component carriers and their configuration is merely an example and other configurations of multiple carriers in a single cell are within the scope of the present disclosure.

[0088] While the message sequence chart 200 of FIG. 2 shows communications between the UE 202 and the MCSC 204, the MCSC 204 represents a frequency band cell, not the recipient or source of communications. In fact, the message sequence chart 200 represents communications between the UE 202 and (network nodes of) a wireless communication network using the MCSC 204. All message sequence charts in the present disclosure, including message sequence chart 200, represent communications between the UE 202 and (network nodes of) a wireless communication network using the MCSC 204.

[0089] The RRC connected mode in operation 206 of FIG. 2 may include MCSC-specific instructions, such as UE capability information to support MCSC or information relating to MCSC-specific channel quality reporting configurations. Operation 208 of FIG. 2 shows LI reporting provided by the UE 202 to the MCSC 204. As described below, the LI reporting may include an indication from the UE 202 that a determination to switch among channel quality reporting configurations (i.e., to switch to an MCSC-specific channel quality reporting configuration from a non-MCSC-specific channel quality reporting configuration or vice versa).

[0090] Operation 210 of FIG. 2 shows a UE Assistance Information (UAI) message sent by the UE 202 to the MCSC 204, the UAI describing MCSC-specific channel quality reporting capabilities the UE 202 is configured to employ. Such MCSC-specific channel quality reporting capabilities may include carrier-grouping, multi-stage CQI, or differential CQI offset values. In alternative embodiments, the MCSC-specific channel quality reporting capabilities of the UE202 are not sent in the UAI message, but may instead be provided in other signaling, such as during the RRC connected mode in operation 206.

[0091] Operation 212 of FIG. 2 is processing performed by the network to determine suitable CQI configurations and switching rules to switch among the CQI configurations that may be used by the UE 202. While FIG. 2 shows operation 212 as performed by the MCSC side of the message sequence chart 200, the MCSC side of the message sequence chart 200 in operation 212 represents one or more nodes of the wireless communication network, which uses the MCSC 204 to communicate with the UE 202. The suitable CQI configurations and switching rules may be determined by the network based on, for example, LI reporting or other reporting or signaling received from the UE 202.

[0092] In operation 214 of FIG. 2, an RRC re-configuration message is sent from the network via the MCSC 204 to the UE 202. The RRC re-configuration message may include CQI offset tables and switching rules for switching between channel quality reporting configurations with reduced overhead for the MCSC (i.e., MCSC-specific channel quality reporting configurations) and reporting configurations with more granular reporting for higher scheduling accuracy but higher overhead. The CQI reporting configurations indicated in the RRC reconfiguration message may be based on the suitable CQI reporting configurations and switching rules determined by the network in operation 212.

[0093] The RRC re-configuration message of operation 214 may also indicate how the UE 202 may inform the network when the UE 202 requires switching between the different configured CQI reporting configurations. For example, the RRC re-configuration message may indicate that the UE 202 may indicate such switching via an in band indication (e.g., indication in an LI report) or via an out of band indication by MAC CE followed by a confirmation from the network. Moreover, the network can also use a MAC-CE to instruct UE 202 to switch between CQI reporting configurations.

[0094] The RRC re-configuration message of operation 214 may also define a multi-stage CQI reporting configuration to reduce the number of bits employed for CQI reporting when propagation characteristics are similar between a configured group of carriers, termed herein as Channel Reporting Group (CRG). This multi-stage CQI reporting configuration may be an MCSC-specific CQI reporting configuration. For example, the three-stage reporting structurecould include a first stage (CRG CQI) that is based on channel measurements / quality estimated over the bandwidth of the CRG (e.g., using 4 bits for the CRG).

[0095] The three-stage reporting structure could also include a second stage (carrier / wideband differential CQI) that is based on the difference in channel quality / measurement estimates at the CRG level and carrier bandwidth level. That is, the second stage may indicate, for each of two carriers in a CRG, the difference between the SINR of the CRG as a whole and the SINR of each respective carrier (e.g., using 2 bits each for 2 carriers in the CRG).

[0096] The three-stage reporting structure could also include a third stage indicating small-scale fading impacts at the sub-band level. For example, the third stage may indicate, for each sub-band within one of the carriers in the CRG, the difference between the SINR of the respective sub-band with respect to the SINR of the carrier as a whole (e.g., using 2 bits each for 2 sub-bands in each carrier). Details of the multi-stage differential CQI reporting are further described below with reference to FIG. 4.

[0097] Once the RRC re-configuration is complete, the UE 202 may perform operation 216, including CQI reporting using an MCSC-specific CQI reporting configuration, such as the multi-stage differential CQI reporting described herein. Based on various measurements (for example, channel measurements) made at the UE 202, the UE may at some point determine that the MCSC-specific CQI reporting configuration is no longer appropriate and that a switch to a non-MCSC-specific channel quality reporting configuration is needed at operation 218.

[0098] In response to this determination at operation 218, the UE 202 may send a message to the network to indicate a switch to another CQI reporting configuration. In the example of FIG. 2, the UE 202 sends an MCSC CQI Configuration Update Request via a MAC CE at operation 220. The MCSC CQI Configuration Update Request indicates to the network that the UE 202 has determined that a switch is needed to a different CQI reporting configuration.

[0099] In alternative embodiments, this update request may be sent by the UE 202 via other means, such as through in band signaling (e.g., LI report). Generally, how to send the CQI configuration update request may be configured in the UE 202 through the RRC re-configuration of operation 214. In response to the CQI configuration update request from the UE 202, the network may respond with an MCSC CQI Config Guidance message confirming the switch to the requested (target) CQI reporting configuration in operation 222.

[0100] While the message sequence chart 200 of FIG. 2 provides a switching framework for switching between different CQI reporting configurations, the switching framework of the present disclosure is not limited to CQI reporting and can be used to signal switching among other reporting configurations, such as other LI reporting over the physical uplink control channel (PUCCH).

[0101] As described above with reference to FIG. 2, the UE 202 can be configured with multiple CQI reporting configurations, including MCSC-specific configurations (such as multitier differential reporting configuration) and non-MCSC-specific configuration. Changing radio channel properties may require the UE 202 or the network to switch from one configuration to another. The messaging framework of the present disclosure, for example as described in FIG. 2, enables the UE 202 to be configured with multiple CQI reporting configurations and enables switching among the multiple CQI reporting configurations based on switching criteria, initiated either by the UE 202 or the network.

[0102] As described above, the UE 202 is configured with multiple CQI reporting configurations. These CQI reporting configuration options may be configured upon request from the UE 202 via the UAI message 210, for example. In this case, as shown in FIG. 2, the network may determine suitable CQI reporting configurations for the UE 202 (in operation 212) and initiate an RRC re-configuration procedure (in operation 214) to provide the UE 202 with the determined suitable CQI reporting configurations along with a method to indicate the switching between the methods.

[0103] In an alternative embodiment, the CQI reporting configuration options may be configured upon the configuration of the MCSC. In this embodiment, the network could provide the UE 202 with different reporting configuration options along with a method to indicate the switching between the methods.

[0104] The UAI message 210 sent by the UE 202 to the network can indicate the following: (i) which carriers can be grouped within the MCSC, and (ii) differential CQI offset values for differential CQI reporting, as described below. The UE 202 may determine the indications to be included in the UAI message 210 based on, for example, measurements of propagation characteristics of the component carriers within the MCSC 204.

[0105] For example, smaller or larger deltas in the differential CQI reporting may be requested by the UE 202, depending on propagation characteristics. The UAI message 210 couldinvolve compressed feedback reporting. In some embodiments, sending the UAI message 210 may not be required since the decision to configure and enable the multiple reporting framework could be network-driven (i.e., not UE-driven).

[0106] One scenario where the UAI message 210 may be used is when propagation characteristics of the configured MCSC carriers are similar for a period of time, in which case the use of MCSC-specific channel quality frameworks is likely to reduce CQI overhead without significantly affecting reporting accuracy. In such cases, a UE is better positioned to store measurements of the carriers for a longer period and determine their propagation similarity, possibly based on some parameters provided by the network.

[0107] Storing the historical measurements of the carriers in the UE frees the network from the burden of storing historical reports for every candidate UE. The network could provide additional parameters to the UE via, for example, an RRC configuration of the MCSC (operation 206 in the example of FIG. 2). The parameters provided from the network to the UE may include a duration period of the carrier measurements or stationary requirements to initiate the measurements (for example, based on reference signal received power (RSRP) deltas).

[0108] Initiating measurements only when the UE is stationary could avoid unnecessary UE storage and processing when the UE is not considered stationary and similar propagation characteristics of the carriers are unlikely. Another parameter provided from the network to the UE may include the number of samples that can be discarded per carrier per measurement period, in order to account for fast fading or bad measurement samples.

[0109] Additionally, the parameters provided from the network to the UE may indicate a maximum variance allowed between carriers, which corresponds to a variance threshold used to trigger switching between different CQI configurations. The UE 202 or the network may determine the differential CQI offset values based on measured carrier / sub-band SINRs. The determined differential CQI offset values may then be transmitted by the UE 202 to the network or from the network to the UE 202 via the UAI 210 (in the case of transmitting from the UE 202 to the network) or via the RRS re-configuration of operation 214 (in the case of transmitting from the network to the UE 202).

[0110] The network will send the RRC re-configuration to the UE 202 either upon reception of the UAI from UE (i.e., after operation 210 in FIG. 2) or upon receiving CQI reporting from the UE and determining, based on the received CQI reporting, to enable anMCSC-specific reporting configuration. The network may send RRC re-configuration (such as the RRC re-configuration in operation 214 in FIG. 2) to the UE 202 for example to confirm or indicate changes in differential CQI offset tables. The differential CQI offset tables map between differential CQI values and applicable offset SINR, as described below.

[0111] The RRC re-configuration (such as the RRC re-configuration in operation 214 in FIG. 2) from the network to the UE 202 may also indicate other pre-configured CQI reporting configurations (i.e., non-MCSC-specific channel quality reporting configurations), and procedures to be used by the UE 202 for switching of CQI reporting configuration. The network may determine the differential CQI offset values / tables indicated in the RRC re-configuration based on sub-band / wideband CQI reports received from the UE 202.

[0112] In some embodiments, the network can also make a coarse mapping of the wideband / sub-band SINRs from the received CQI reports and use the coarse mapping values for CQI offset calculations. An example of calculation of the offset values for MCSC-specific CQI reporting is described below. CQI reporting from the UE 202 to the network, which is used by the network for the RRC re-configuration may take various forms.

[0113] For example, the network may receive the CQI reporting only on the reference carrier of the MCSC when switching is triggered. In another embodiment, the network may receive the CQI report on a group of carriers (e.g., the reference carrier and other carriers of the MCSC with similar radio conditions) using an MCSC-specific configuration. Other carriers (i.e., carriers within the MCSC but outside the group) may not be reported or may be reported with a different periodicity i.e., less or more frequently than the reference carrier depending on if the other carriers’ CQI is better or worse than the grouped carriers).

[0114] The number of carriers for group reporting and the reporting periodicity scheme may be communicated by the UE 202 to the network (e.g. via UAI or MAC-CE). In some embodiments, the network may receive CQI reporting on all carriers in a time interleaved manner. For example, if periodic reporting were set up for 40ms, then the CQI report of first carrier of the MCSC is sent at X ms, the CQI report of a second carrier of the MCSC is sent at X ms+40 ms, the CQI report of a third carrier of the MCSC is sent at X ms+80 ms., etc.

[0115] Other schemes of CQI reporting of the carriers of the MCSC are within the scope of the present disclosure. Generally, in the embodiment described with reference to FIG. 2, the UE 202 provides to the network channel measurements such as SINR of one or more carriers inthe MCSC in order for the network to determine suitable CQI reporting configurations, including potentially MCSC-specific CQI reporting configurations.

[0116] In some embodiments, the network could also indicate to the UE 202 how to provide network channel measurements based on the active services / QoS requirements of the UE 202. For example, if the UE 202 has an active voice call, the network may indicate that the UE 202 should only report on the reference carrier and the next best carrier.

[0117] As described above, the present disclosure describes an MCSC-specific channel quality reporting (for example, CQI reporting) configuration, which may be referred to herein as a multi-stage CQI reporting configuration. As noted above, CQI reporting is used for some examples herein, yet the present disclosure may be applied to other channel quality reporting methods, such that the MCSC-specific channel quality reporting may be a multi-stage RSRP reporting configuration or a multi-stage SINK, reporting configuration, and the like. This configuration reduces the number of bits used for channel quality reporting by leveraging the channel measurement similarities among a specific group of carriers of the MCSC, which may be referred to herein as a Channel Reporting Group (CRG).

[0118] The multi-stage channel quality reporting configuration may be a 3 -stage CQI feedback scheme such as the one shown in FIG. 3. In FIG. 3, the first stage 302 is a CRG CQI stage, which is based on the SINR estimated over the entire bandwidth of the CRG. That is, the first stage of this multi-stage CQI reporting configuration reports a CQI value corresponding to the SINR that is estimated across all carriers in the CQI Reporting Group. For example, 4 bits may be used to report the CQI value for the CRG.

[0119] The second stage 304 of the multi-stage CQI reporting configuration shown in FIG. 3 is a carrier-specific differential CQI, which is based on the difference in SINR estimates at the CRG level and at the carrier level. In other words, the values reported at the second stage 304 represent, for one or more carriers in the CRG, the difference between the channel measurement (e.g, SINR / SNR) of the respective carrier and the channel measurement (e.g, SINR / SNR) of the CRG (i.e., corresponding to the value reported at the first stage 302). For example, 2 bits may be used to report the differential CQI value of each carrier in the CRG at the second stage 304.

[0120] The third stage 306 of the multi-stage CQI reporting configuration shown in FIG. 3 is a sub-band differential CQI, which is based on the difference in SINR estimates at the sub-band level and at the carrier level. In other words, the values reported at the third stage 306 represent, for one or more sub-bands within one of the carriers of the CRG, the difference between the channel measurement (e.g., SINR / SNR) of the respective sub-band and the channel measurement (e.g., SINR / SNR) of the carrier (i.e., corresponding to the value reported at the second stage 304).

[0121] For example, 2 bits may be used to report the differential CQI value of two subbands in a carrier in the CRG at the third stage 306. Of the three stages described above with respect to FIG. 3, the third stage 306 is most granular, but may be used / transmitted less often due to availability of less granular reports at the first stage 302 and second stage 304. Accordingly, the multi-stage CQI reporting scheme described herein achieves CQI reporting using fewer bits, thereby improving overall signaling efficiency and improving power efficiency at the UE. As noted above, the multi-stage reporting scheme may also extend to channel quality reporting values other than CQI, such as RSRP, SINR, and the like.

[0122] FIG. 4 provides an example of the 3 -stage channel quality reporting scheme of FIG. 3 applied to an MCSC cell with five carriers forming a CRG. As shown in FIG. 4, the five carriers in the CRG have similar radio channel properties, with the graph capturing small scale fading across the carriers. At the first stage 302 of the 3-stage channel quality reporting configuration, a CRG channel measurement (SINR / SNR) is obtained by determining an average / estimated SINR / SNR across all five carriers. While the example of FIG. 4 measures SINR or SNR values, other channel measurements indicative of channel quality may be taken additionally or alternatively within the scope of the present disclosure.

[0123] In the example of FIG. 4, the CRG SINR / SNR is determined to be 10 dB, as represented by the dashed horizontal line. The determined CRG SINR / SNR is then converted to a 4-bit code based on a pre-configured CRG CQI table, such as Table 1 below. As shown in FIG.4, the determined CRG SINR / SNR corresponds to a CRG CQI code of 1010.Table 1

[0124] Table 1 is an example of 4-bit codes that may be used to represent various dB levels across the CRG. For example, 0000 is representative of a 0 dB SINR or SNR averaged across the carriers (or frequency band) of the CRG, 0001 is representative of a 1 dB SINR or SNR across the CRG, etc. In some embodiments, the CRG CQI table may allocate one 4-bit code to be used as an in-band indication that the current CQI reporting configuration is to be switched to a different pre-configured CQI reporting configuration (i.e., switch from an MCSC-specific CQI reporting configuration to a non-MCSC-specific CQI reporting configuration).

[0125] At the second stage 304 of the 3 -stage CQI reporting configuration, the wideband estimated SINR / SNR values for the carriers are determined by the UE 202 and the differences between the carrier-level SINR / SNR values and the CRG-level SINR / SNR value determined at the first stage 302. The differences are quantized into 2-bit wideband differential CQI values based on offset tables, such as Table 2 below.Table 2

[0126] Table 2 is an example of 2-bit codes that may be used to represent various dB differences between a carrier-level SINR / SNR and the CRG-level SINR / SNR for the second stage 304. For example, 00 is representative of a +1 dB difference between a carrier-level SINR or SNR, as compared to the SINR or SNR across the CRG, 01 is representative of a +2 dB difference between a carrier-level SINR or SNR, as compared to the SINR or SNR across the CRG, etc. A table similar to Table 2 may be used in the third stage 306 to determine differential1CQI levels to represent the differences between the SINR / SNR of respective sub-bands and the SINR / SNR values of the carrier of the sub-bands.

[0127] In the example of FIG. 4, the carrier-level wideband differential CQI reporting for the second stage 304 is shown at the top of the graph. The wideband average estimated SINR / SNR levels for each of carriers 1 through 5 are shown respectively as dotted lines within each carrier. The wideband differential CQI levels for each of the five carriers are therefore representative of the difference between the wideband average estimated SINR / SNR level for the respective carrier and the CRG average estimated SINR / SNR. In other words, the wideband differential CQI for a carrier represents the delta between the dotted line within that carrier and the dashed horizontal line across all carriers representing the CRG average estimated SINR / SNR.

[0128] In the example of FIG. 4, the sub-band differential CQI reporting for the third stage 306 is shown at the bottom of the graph. The sub-band SINR / SNR levels within each of the carriers 1 through 5 are shown as the freeform curve across the graph. The sub-band differential CQI levels within each of the five carriers are therefore representative of the difference between the wideband average estimated SINR / SNR level for the respective carrier and the SINR / SNR level at each sub-band within the respective carrier. In other words, the sub-band differential CQI for a sub-band in a carrier represents the delta between the dotted line within that carrier and the value of the freeform curve within the sub-band.

[0129] While the examples of FIG. 4 and Tables 1 and 2 provide particular differential offset values for signaling the differential CQI, these offset values are examples only and other offset values may be selected by the UE 202 or the network. For example, the UE 202 or the network may determine the range of carrier-level wideband SNR / SINR values of all carriers with respect to the CRG average SNR / SINR value and determine appropriate quantization levels based on how the range relates to the CRG average SNR / SINR value.

[0130] In some embodiments, the UE 202 or the network may determine appropriate quantization levels or the number of required quantization levels in light of predefined accuracy requirements. Additionally, the selected quantization levels may be cross-checked by the network to ensure applicable accuracy requirements are met. Based on the determined number of required quantization levels, the UE 202 or the network can arrive at the offset correspondence tables, such as Tables 1 and 2 above.

[0131] The MCSC-specific 3 -stage channel quality reporting described above with reference to FIGS. 3 and 4 achieves a more efficient reporting overhead as compared to a differential CQI that does not include the first stage 302 reporting (CRG CQI) associated with a carrier group. Table 3 below captures the advantage of the MCSC-specific 3-stage channel quality reporting configuration described herein, assuming five carriers per CRG and assuming four sub-bands per carrier.Table 3

[0132] Table 3 shows that, for MCSC-specific 3-stage channel quality reporting, there is a reduction in the total reported bits as compared to generic differential CQI reporting. This efficiency is achieved because the 3-stage channel quality reporting method reports the wideband / carrier-level channel quality as a differential value, relative to the CRG value. There will also be an additional reduction in channel quality signaling overhead because the reporting of the CRG value (first stage 302) will be less frequent as compared to the wideband / carrier-level differential value (second stage 304).

[0133] As noted above, an MCSC-specific channel quality reporting configuration leverages the similarity of radio / spatial channel conditions among the carriers forming a CRG. Such similarity can help reduce the channel quality reporting overhead, while satisfying accuracy and reliability requirements. However, if the similarity conditions cannot be maintained, then the UE 202 can trigger switching of the channel quality reporting configuration by sending an appropriate indication to the network.

[0134] The flowchart in FIG. 5 provides an algorithm to switch between MCSC-specific and non-MCSC-specific channel quality reporting configurations at the UE side based on estimated SINR / SNR variance (wideband carrier-level SINR / SNR) among the CRG carriers. The variations of SINR / SNR at the carrier level represent variations in radio conditions, which in turn affect whether MCSC-specific CQI reporting can be leveraged. While the example of FIG. 5 uses measured SINR or SNR channel values, the algorithm of FIG. 5 is applicable to other channel measurements representative of channel quality.

[0135] The steps shown in FIG. 5 are performed by a UE that is configured to communicate with a wireless communication network via an MCSC and is further configured to group carriers in the MCSC into a CRG. The UE may be pre-configured with plural channel quality reporting configurations, including an MCSC-specific CQI reporting configuration (such as the 3 -stage CQI reporting configuration described above with reference to FIGS. 3 and 4) and one or more non-MCSC-specific CQI reporting configurations.

[0136] At operation 502, the UE may estimate the wideband channel measurements (e.g., SINR / SNR) for each carrier of a CRG. Then, at operation 504, the UE may use the estimated SINR / SNR values for each carrier to calculate a wideband SINR / SNR variance across carriers of the CRG. That is, the UE may analyze the SINR / SNR values of the carriers of the CRG and calculate a wideband variance parameter that captures how widely the carrier SINR / SNR values of the carriers vary from the average estimated SINR / SNR of the CRG.

[0137] At operation 506, the UE determines whether the wideband variance parameter exceeds a threshold. The threshold value may be pre-configured in the UE or may be determined by or communicated to the UE. The threshold value used at operation 506 may be specified in a relevant standard, such as RAN2 or RAN4, and may be a function of accuracy requirements, such as block error rate (BLER) requirements, throughput requirements, etc.

[0138] If the UE determines at operation 506 that the wideband variance parameter does not exceed the threshold, then the estimated SINR / SNR values of the carriers within the CRG are close enough to the estimated SINR / SNR of the CRG in order to leverage channel similarities by using the MCSC-specific channel quality reporting configuration described above. As such, the “no” branch from operation 506 leads to operation 508, at which the UE may perform the MCSC-specific channel quality reporting.

[0139] If the UE determines at operation 506 that the wideband variance parameter does exceed the threshold, then the estimated SINR / SNR values of the carriers within the CRG are too different from the estimated SINR / SNR of the CRG and using the MCSC-specific channel quality reporting configuration in this case would not meet accuracy requirements or would not otherwise afford the signaling overhead efficiencies described above. In this case (i.e., the “yes” branch from operation 506), the UE indicates to the network that the CQI reporting configuration is to be switched in operation 510.

[0140] In some embodiments, the UE at operation 506 also indicates which CQI reporting configuration to switch to, for example the UE indicates a pre-configured non-MCSC-specific channel quality reporting configuration. In such embodiments, after operation 506, the network and UE would proceed to switch to the indicated non-MCSC-specific channel quality reporting configuration.

[0141] In some embodiments, the network and the UE will store conditions under which to switch back (or fallback) to non-MCSC-specific channel quality reporting configurations. For example, the network may determine to fallback to non-MCSC-specific channel quality reporting configurations if the delta (A or difference) between channel measurements of the different carriers (for example, from second stage 304 of the MCSC-specific channel quality reporting) or the CRG channel quality value (for example, from first stage 302 of the MCSC-specific channel quality reporting) and the median channel quality value do not fulfill certain accuracy requirements (for example, CQI accuracy requirements defined as part of the RAN4 definitions).

[0142] FIG. 6 shows an algorithm that may be performed by the network to switch between MCSC-specific and non-MCSC-specific channel quality reporting based on calculated A of received CQI reports. For example, the network may be configured to support an MCSC and may further be configured with a CRG. The network may also store plural channel quality reporting configurations, including MCSC-specific and non-MCSC-specific channel quality reporting configurations. While the example of FIG. 6 uses CQI values, the algorithm of FIG. 6 is applicable to other channel quality values, such as SINR values, SNR values, RSRP values, and the like.

[0143] In operation 602, the network calculates the average difference (or A) between CQI values reported by a UE and a median CQI value. The CQI values reported by the UE include CQI values for each of the carriers of a CRG (reported as part of the second stage 304 of theMCSC-specific channel quality reporting) and also include the CRG CQI value (reported as part of the first stage 302 of the MCSC-specific channel quality reporting).

[0144] The median CQI value may be, for example, the median of CQI values received in one or more of the first stage 302, the second stage 304, and the third stage 306 of the MCSC-specific channel quality reporting. The average difference calculated in operation 602 may be the average of the differences between (i) each CQI value received for the carriers and the CRG and (ii) the median CQI value.

[0145] In operation 604, the network determines whether the average difference calculated in operation 602 is greater than a difference threshold. The difference threshold may be stored in or determined by the network to represent a reliability threshold over which the CQI reporting is not reliable. If the average difference calculated in operation 602 is below or equal to the difference threshold (“no” branch from operation 604), then the network continues to receive MCSC-specific channel quality reporting from the UE in operation 606.

[0146] On the other hand, if the average difference is determined to be greater than the difference threshold (“yes” branch in operation 604), then the network indicates to the UE in operation 608 to switch from an MCSC-specific channel quality reporting configuration to a non-MCSC-specific channel quality reporting configuration. In some embodiments, the network may indicate in operation 608 a pre-configured CQI reporting framework to which the UE is to switch.

[0147] When the UE indicates a CQI reporting switch in operation 510 or when the network indicates switching of CQI reporting configuration in operation 608, the switching indications may be sent either in-band or out-of-band. An in-band switching indication may use a special reserved bit pattern that may be included in MCSC-specific channel quality reports.

[0148] For example, Table 1 above shows a reserved bit pattern (1111) in the CRG CQI table, the bit pattern being reserved for use as a switching indication. The UE may include this reserved bit pattern in a CQI report to indicate to the network that a CQI configuration switch is needed, for example due to a determination that switching criteria are met.

[0149] In some embodiments, the UE will switch to a non-MCSC-specific CQI reporting configuration after transmitting the reserved bit pattern as a switching indication in a CQI report. In some embodiments, the switching criteria may be based on the number of carriers in a CRG that have a large differential CQI value, as compared to the other carriers in the CRG.

[0150] For example, the number of carriers with a large differential CQI value that would meet the switching criteria may be configured by the network to ensure both the network and UE store consistent switching criteria. Because CQI reports sent by a UE over a PUCCH are not retransmitted, the network may also configure a minimum number of reports transmitted by the UE with the switching indication (e.g., the reserved bit pattern) before the UE switches to a different (non-MCSC-specific) CQI reporting configuration.

[0151] In some embodiments, channel conditions of one or more carriers in a CRG may degrade or change, such that these carriers no longer belong in the CRG. In this case, the UE may send a medium access control (MAC) control element (CE) indicating which carriers need to be removed from the channel reporting group (CRG) within an MCSC.

[0152] For example, the UE may send an MCSC CQI Config Update Request MAC CE to the network indicating the carriers to be removed from the CRG. The MAC CE may also include a switching indication indicating that the UE is switching to a non-MCSC-specific channel quality reporting configuration. The network may respond to the MCSC CQI Config Update Request MAC CE with a confirmation MAC CE (e.g, MCSC CQI Config Guidance MAC CE) to confirm the reconfiguration of the CRG to remove certain carriers and / or to confirm the switch to a non-MCSC-specific channel quality reporting configuration.

[0153] The transmission of MAC CE messages by the UE or the network to indicate switching to a different (e.g., non-MCSC-specific) CQI reporting configuration is referred to herein as an out of band indication. The switching indication may also be sent by the network in the MCSC CQI Config Guidance MAC CE to initiate switching based on the criteria described above with respect to FIG. 6.

[0154] The MCSC CQI Config Guidance MAC CE sent from the network as a switching indication may also include information regarding existing or new reporting configurations to be switched to by the UE. Examples of in band and out of band switching indications are provided in FIGS. 7 and 8, respectively. For example, FIG. 7 shows an example of an in band switching indication sent from a UE to a network via an MCSC.

[0155] In FIG. 7, a UE 702 communicates with a network over three carriers (Reference Carrier 1, Carrier 2, and Carrier 3) that are part of an MCSC. In the example of FIG. 7, these three carriers are grouped together in a Channel Reporting Group (CRG) 704. As in the example of FIG. 2, the message transmissions shown in FIG. 7 are not between the UE 702 and the threecarriers, but rather the transmissions are between the UE 702 and the network (z.e., one or more network nodes), sent via the three carriers in the CRG 704.

[0156] In the example of FIG. 7, the 3-stage MCSC-specific CQI reporting configuration described above with reference to FIGS. 3 and 4 is configured and in use. Initially, the 3-stage MCSC-specific CQI reporting is shown as messages 706, which include a first stage CRG CQI message, a second stage wideband (carrier-level) differential CQI message, and multiple subband level differential CQI messages. While the example of FIG. 7 shows a 3-stage MCSC-specific CQI reporting configuration, another MCSC-specific channel quality reporting method may also be used, such as RSRP reporting, SINR reporting, SNR reporting, or the like.

[0157] After the initial 3-stage MCSC-specific CQI reporting is complete, the example of FIG. 7 shows regular data transmission 708 between the UE 702 and the network via the CRG 704. Then, additional sub-band differential CQI reporting 710 is transmitted by the UE 702. The additional sub-band differential CQI reporting 710 shows that, in the 3-stage MCSC-specific CQI reporting, third stage sub-band level reporting is more frequent than first stage CRG CQI reporting and second stage wideband carrier-level reporting because the sub-band level reporting captures small-scale fading and is therefore sent more frequently.

[0158] At operation 712, the UE 702 determines that switching conditions have been met for a switch to a non-MCSC-specific channel quality reporting configuration. For example, channel conditions of the carriers in the CRG have diverged or deteriorated and / or other conditions have been met that are configured as CQI reporting switching conditions.

[0159] In response to the determination at operation 712 that switching conditions have been met, the UE 702 sends an in band switching indication 714. Specifically, the in band switching indication 714 is a CRG CQI message including a reserved bit pattern 1111 that is reserved for switching indication. In response to the switching indication 714, both the UE 702 and the network switch to the non-MCSC-specific channel quality reporting configuration at operation 716.

[0160] Thereafter, the non-MCSC-specific channel quality reporting is shown as messages 718. Specifically, these messages do not include the MCSC-specific CRG CQI message. Additionally, the wideband carrier-level CQI message in the messages 718 is not a differential message. In contrast, FIG. 8 shows a similar CQI reporting configuration switchingoperation as FIG. 7, except the switching indication is sent by the UE in an out of band message that also indicates a re-configuration of the CRG.

[0161] In FIG. 8, a UE 802 communicates with a network over three carriers (Reference Carrier 1, Carrier 2, and Carrier 3) that are part of an MCSC. In the example of FIG. 8, these three carriers are grouped together in a Channel Reporting Group (CRG) 804. As in the examples of FIGS. 2 and 7, the message transmissions shown in FIG. 8 are not between the UE 802 and the three carriers, but rather the transmissions are between the UE 802 and the network (i.e., one or more network nodes), sent via the three carriers in the CRG 804. Additionally, while the examples of FIGS. 2, 7, and 8 use MCSC-specific CQI reporting, a different MCSC-specific channel quality reporting mechanism may be used, such as RSRP reporting, SINR reporting, SNR reporting, or the like.

[0162] As in the example of FIG. 7, the 3-stage MCSC-specific channel quality reporting is performed in the example of FIG. 8 as messages 806, which include a first stage CRG CQI message, a second stage wideband (carrier-level) differential CQI message, and multiple subband level differential CQI messages. As in the example of FIG. 7, after the MCSC-specific CQI reporting 806 is complete, regular data transmission 808 occurs between the UE 802 and the network via the CRG 804.

[0163] Then, additional sub-band differential CQI reporting 810 is transmitted by the UE 802 in the example of FIG. 8, as in the example of FIG. 7. In operation 812, the UE 802 determines that switching conditions have been met to switch to a non-MCSC-specific CQI reporting configuration, similar to operation 712 in FIG. 7. After operation 812, the out of band switching indication methodology of FIG. 8 diverges from the in band switching indication shown in FIG. 7.

[0164] Specifically, in operation 812, the UE 802 determines that the channel conditions of carrier 3 of the CRG 804 have changed enough such that carrier 3 is no longer similar enough to the other carriers of the CRG 804. For example, the UE 802 may make such a determination based on the algorithm of FIG. 5, which may indicate at operation 506 that the wideband variance of carrier 3 exceeds a threshold.

[0165] In response to the determination, the UE 802 may send a MAC CE to the network indicating that the channel conditions of channel 3 have changed and that the channel conditions of carriers 1 and 2 of the CRG 804 remain similar. For example, the UE 802 may send an MCSCCQI Config Update Request MAC CE 814 with an indication that carrier 3 is no longer similar / related to reference carrier 1 and reference carrier 2 and that reference carrier 1 and carrier 2 remain similar / related to one another.

[0166] In response to receiving the MAC CE from the UE 802 in operation 814, the network responds with a MAC CE instructing the UE 802 to split the CRG 804 so that reference carrier 1 and carrier 2 remain in the CRG 804 and will continue to report CQI via the MCSC-specific 3 -stage CQI reporting configuration, while carrier 3 will be removed from the CRG 804 and will be reported using a non-MCSC-specific channel quality reporting configuration.

[0167] In the example of FIG. 8, the network responds with an MCSC CQI Config Guidance MAC CE 816 to indicate the above-described CRG split and to provide guidance as to how the CQI of each CRG is to be reported. As an alternative embodiment of operations 814 and 816, the UE 802 may send in the MAC CE of operation 814 a CRG reconfiguration indication to split the CRG as described above. In this embodiment, the network may respond with a MAC CE 816 to confirm the CRG reconfiguration in which carrier 3 is removed from CRG 804 and reported using a non-MCSC-specific channel quality reporting configuration.

[0168] After operation 816, carrier 3 is removed from CRG 804 and placed in a new CRG 818, as shown in FIG. 8. Afterward, the CQI of CRG 804 continues to be reported using the MCSC-specific 3-stage CQI reporting configuration described above, in messages 820. Similarly to earlier MCSC-specific CQI reporting messages 806, messages 820 include a first stage CRG CQI report, a second stage wideband carrier-level differential CQI report, and several sub-band differential CQI reports.

[0169] On the other hand, new CRG 818 including carrier 3 is reported using non-MCSC-specific CQI reporting in messages 822. In this CQI reporting, there is no first stage CRG CQI report and the wideband carrier-level report is not differential.

[0170] FIG. 9 illustrates an example of an apparatus 900 configured to practice one or more example embodiments. The apparatus 900 may comprise a UE such as UE 202, 702, or 802 or a base station, an access point, a radio network node, a network device, or in general any apparatus configured to implement functionality described herein.

[0171] The apparatus 900 may comprise at least one processor 902. The at least one processor 902 may comprise, for example, one or more of various processing devices, such as for example a co-processor, a microprocessor, a controller, a digital signal processor (DSP), aprocessing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like.

[0172] The apparatus 900 may further comprise at least one memory 904. The memory 904 may be configured to store, for example, computer program code 906 or the like, for example operating system software and application software. The memory 904 may comprise one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination thereof. For example, the memory 904 may be embodied as magnetic storage devices (such as hard disk drives, magnetic tapes, etc.), optical magnetic storage devices, or semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.).

[0173] The apparatus 900 may further comprise one or more communication interfaces 908 configured to enable apparatus 900 to transmit and / or receive information, to / from other apparatuses. The communication interface may be configured to provide at least one wireless radio connection, such as for example a 3 GPP mobile broadband connection (e.g. 3G, 4G, 5G, or beyond). However, the communication interface 908 may be configured to provide one or more other type of connections, for example a wireless local area network (WLAN) connection such as for example standardized by IEEE 802.11 series or Wi-Fi alliance; a short range wireless network connection such as for example a Bluetooth, NFC (near-field communication), or RFID connection; a wired connection such as for example a local area network (LAN) connection, a universal serial bus (USB) connection or an optical network connection, or the like; or a wired Internet connection. The communication interface 908 may comprise, or be configured to be coupled to, at least one antenna to transmit and / or receive radio frequency signals. One or more of the various types of connections may be also implemented as separate communication interfaces, which may be coupled or configured to be coupled to a plurality of antennas.

[0174] The apparatus 900 may further comprise a user interface 910 comprising an input device and / or an output device. The input device may take various forms such a keyboard, a touch screen, or one or more embedded control buttons. The output device may for example comprise a display, a speaker, a vibration motor, or the like.

[0175] When the apparatus 900 is configured to implement some functionality, some component and / or components of the apparatus 900, such as for example the at least one processor 902 and / or the memory 904, may be configured to implement this functionality. Furthermore, when the at least one processor 902 is configured to implement some functionality, this functionality may be implemented using program code 906 comprised, for example, in the memory 904.

[0176] The functionality described herein may be performed, at least in part, by one or more computer program product components such as software components. According to an embodiment, the apparatus 900 comprises a processor or processor circuitry, such as for example a microcontroller, configured by the program code when executed to execute the embodiments of the operations and functionality described. Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), application-specific Integrated Circuits (ASICs), application-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), Graphics Processing Units (GPUs).

[0177] The apparatus 900 comprises means for performing at least one method described herein. In one example, the means comprises the at least one processor 902, the at least one memory 904 including program code 906 configured to, when executed by the at least one processor 902, cause the apparatus 900 to perform the method.

[0178] The apparatus 900 may comprise for example a computing device such as for example a base station, a network node, a server device, a client node, a mobile phone, a tablet computer, a laptop, or the like. In one example, the apparatus 900 may comprise a vehicle such as for example a car. Although the apparatus 900 is illustrated as a single device it is appreciated that, wherever applicable, functions of apparatus 900 may be distributed to a plurality of devices.

[0179] FIG. 10 illustrates an example of a method for CQI reporting in a communication network according to an example embodiment. The method 1000 may be performed by a user equipment, or by an apparatus configured to control the functioning thereof, when installed therein.

[0180] At operation 1002, the method may comprise receiving, from a network node providing a cell with plural carriers, configuration information indicating plural configurationsfor channel quality index reporting, CQI reporting. At least one of the plural configurations is a configuration associated with a CQI reporting group, CRG, that comprises at least some carriers of the plural carriers.

[0181] At operation 1004, the method may comprise obtaining measurement values for the configuration associated with the CRG based on the received configuration information and based on channel measurements over a bandwidth of the CRG. At operation 1006, the method may comprise transmitting CQI reporting for the CRG based on the obtained measurement values for the configuration associated with the CRG.

[0182] FIG. 11 illustrates an example of a method for CQI reporting in a communication network according to an example embodiment. The method 1100 may be performed by network node of the communication network, or by an apparatus configured to control the functioning thereof, when installed therein.

[0183] At operation 1102, the method may comprise transmitting, to a user equipment, UE, configuration information indicating plural configurations for channel quality index reporting, CQI reporting, including a configuration associated with a CQI reporting group, CRG, that comprises plural carriers. At operation 1104, the method may comprise receiving, from the UE, CQI reporting for the CRG based on obtained channel measurements over a bandwidth of the CRG for the configuration associated with the CRG.

[0184] Further features of the methods directly result from the functionalities and parameters of the apparatuses, as described in the appended claims and throughout the specification and are therefore not repeated here. It is noted that one or more operations of the method may be performed in different order.

[0185] An apparatus, for example a network node, a base station, a TRP, a user node or a client node, may be configured to perform or cause performance of any aspect of the method(s) described herein. Further, a computer program may comprise instructions for causing, when executed, an apparatus to perform any aspect of the method(s) described herein. Further, an apparatus may comprise means for performing any aspect of the method(s) described herein. According to an example embodiment, the means comprises at least one processor, and memory including program code, the at one memory and the program code configured to, when executed by the at least one processor, cause performance of any aspect of the method(s).

[0186] As described above, advantages of the disclosed CQI reporting framework include a lower-bit, more efficient CQI configuration that is MCSC-specific. Specifically, the MCSC-specific channel quality reporting configuration leverages channel similarities among carriers that are grouped together in a CRG within the MCSC.

[0187] The carriers of the MCSC are grouped into the CRG based on channel similarities among the carriers and, consequently, a more efficient 3 -stage CQI configuration based on differential reporting can be used to

Claims

35CLAIMS1. An apparatus, comprising:at least one processor; andat least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus at least to:receive, from a network node providing a cell with plural carriers, configuration information indicating plural configurations for channel quality reporting, wherein at least one of the plural configurations is a configuration associated with a channel reporting group, CRG, that comprises at least some carriers of the plural carriers;obtain measurement values for the configuration associated with the CRG based on the received configuration information and based on channel measurements over a bandwidth of the CRG; andtransmit channel quality reporting for the CRG based on the obtained measurement values for the configuration associated with the CRG.

2. The apparatus of claim 1, wherein the plural configurations of channel quality reporting comprise:a first configuration that is the configuration associated with the CRG;a second configuration for indicating a difference between (i) the channel measurements over the bandwidth of the CRG and (ii) channel measurements over a bandwidth of one of the plural carriers of the CRG; anda third configuration for indicating a difference between (i) the channel measurements over a bandwidth of the one of the plural carriers of the CRG and (ii) measurements over a subband of the one of the plural carriers of the CRG.

363. The apparatus of any preceding claim, whereinthe channel quality reporting comprises at least one of (i) channel quality index, CQI, reporting; (ii) reference signal received power, RSRP, reporting; or (iii) signal to interference plus noise ratio, SINR, reporting; andthe configuration information comprises: (i) offset values for the channel quality reporting; and (ii) parameters for the apparatus to select one of the plural configurations of channel quality reporting, the parameters including at least a variance threshold for selecting one of the plural configurations of channel quality reporting based on whether a variance among the channel measurements of the plural carriers of the CRG is below the variance threshold.

4. The apparatus of any preceding claim, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:transmit, to the network node, assistance information indicating that the apparatus supports one or more reporting configurations associated with the CRG, wherein the assistance information further indicates at least one of: (i) the plural carriers of the CRG; or (ii) differential offset values for the channel quality reporting based on channel measurements of the plural carriers of the CRG; andtransmit, to the network node, an indication of switching from a current channel quality reporting configuration to a target channel quality reporting configuration, wherein the indication of switching is transmitted in band or via MAC CE.

5. The apparatus of any preceding claim, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:select the configuration associated with the CRG when the variance among the channel measurements of the plural carriers of the CRG is below the variance threshold; andtransmit, to the network node, an indication that the configuration associated with the CRG is selected by the apparatus.

6. The apparatus of claim 5, wherein the indication that the configuration associated with the CRG is selected by the apparatus is transmitted to the network node in a channel quality report or a medium access control, MAC, control element, CE.

7. An apparatus, comprising:at least one processor; andat least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus at least to:transmit, to a user equipment, UE, configuration information indicating plural configurations for channel quality reporting, including a configuration associated with a channel reporting group, CRG, that comprises plural carriers, wherein the transmitted configuration information further comprises (i) parameters for the UE to switch among the plural configurations for channel quality reporting and (ii) whether the UE is to transmit a switching indication in a channel quality report or in a MAC CE ; andreceive, from the UE, channel quality reporting for the CRG based on obtained channel measurements over a bandwidth of the CRG for the configuration associated with the CRG.

8. The apparatus of claim 7, wherein the plural configurations of channel quality reporting includea first configuration that is the configuration associated with the CRG,a second configuration for indicating a difference between (i) the channel measurements over the bandwidth of the CRG and (ii) channel measurements over a bandwidth of one of the plural carriers of the CRG, anda third configuration for indicating a difference between (i) the channel measurements over a bandwidth of the one of the plural carriers of the CRG and (ii) measurements over a subband of the one of the plural carriers of the CRG.

9. The apparatus of claim 7 or 8, whereinthe at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:receive, from the UE in a channel quality report or in a MAC CE, an indication that the configuration associated with the CRG is selected by the UE; andthe channel quality reporting comprises at least one of (i) channel quality index, CQI, reporting; (ii) reference signal received power, RSRP, reporting; or (iii) signal to interference plus noise ratio, SINR, reporting.

10. The apparatus of claim 9, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: when the indication that the configuration associated with the CRG is selected by the UE is received in a MAC CE, transmit, to the UE in a MAC CE, a confirmation in response to the indication.

11. The apparatus of any of claims 7-10, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:receive, from the UE, channel quality values respectively corresponding to one or more of the plural carriers of the CRG;calculate an average difference between the channel quality values and a median channel quality value of the CRG;when the calculated average difference is greater than a threshold, transmit an indication to the UE that a channel quality reporting configuration switch is needed.3912. The apparatus of claim 7 or 8, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:receive, from the UE, a channel quality report or LI measurement report;select, based on the received channel quality report or LI measurement report, one of the plural configurations for channel quality reporting; andtransmit, to the UE, an indication of the selected one of the plural configurations for channel quality reporting, wherein the indication is transmitted in a MAC CE.

13. A method, comprising:receiving, by a user equipment, UE, from a network node providing a cell with plural carriers, configuration information indicating plural configurations for channel quality reporting, including a configuration associated with a channel reporting group, CRG, that comprises at least some carriers of the plural carriers;obtaining, by the UE, measurement values for the configuration associated with the CRG based on the received configuration information and based on channel measurements over a bandwidth of the CRG; andtransmitting, by the UE, channel quality reporting for the CRG based on the obtained measurement values for the configuration associated with the CRG.

14. The method of claim 13, further comprising:selecting, by the UE, the configuration associated with the CRG when a variance among the channel measurements of the plural carriers of the CRG is below a variance threshold; and transmitting, by the UE to the network node, an indication that the configuration associated with the CRG is selected by the UE.4015. A method, comprising:transmitting, to a user equipment, UE, by a network node providing a cell with plural carriers, configuration information indicating plural configurations for channel quality reporting, including a configuration associated with a channel reporting group, CRG, that comprises at least some carriers of the plural carriers, wherein the transmitted configuration information further comprises (i) parameters for the UE to switch among the plural configurations for channel quality reporting and (ii) whether the UE is to transmit a switching indication in a channel quality report or in a MAC CE; andreceiving, by the network node from the UE, channel quality reporting for the CRG based on obtained channel measurements over a bandwidth of the CRG for the configuration associated with the CRG.

16. The method of claim 15, further comprising:receiving, by the network node from the UE, channel quality values respectively corresponding to one or more of the plural carriers of the CRG;calculating an average difference between the channel quality values and a median channel quality value of the CRG;when the calculated average difference is greater than a threshold, transmitting an indication to the UE that a channel quality reporting configuration switch is needed.

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