Power-efficient means of operating a user equipment (UE) in multi-

Abstract

The present disclosure provides systems, methods, apparatuses, computer programs encoded on a computer readable medium for a user equipment (UE) receiving a reference signal from a first base station, performing radio resource management (RRM) measurements based on the reference signal, and transmitting information regarding the RRM measurements to a second base station. In another aspect, a UE receives a reference signal from a first base station, performs a channel quality indicator (CQI) measurement based on the reference signal, stores information on the CQI measurement, and transmits the stored information to the first base station. In another aspect, a base station receives, from a UE, information associated with CQI measurements related to a second base station, and sends the information to the second base station.

Description

[0001] This application is a continuation-in-part of patent application no. 202080098730.3 with application date of 26-March-2020, entitled “Power efficient ways of operating user equipment (UE) in multi-radio access technology dual connectivity”, having the same assignee herewith. TECHNICAL FIELD

[0002] The technology discussed below relates generally to wireless communication systems or networks, and more particularly, to operating a user equipment (UE) in a dormant or deactivated power efficient state with respect to a secondary base station or node (SN) in a dual connectivity configuration with a master base station or node (MN). BACKGROUND

[0003] In many existing wireless communication systems, cellular networks are implemented by enabling wireless user equipment to communicate with each other through signaling with one or more nearby base stations or cells. As user equipment (UEs) move across a service area, handovers occur so that each UE remains in communication with each other via their respective base stations and associated one or more cells. In a dual connectivity configuration, a UE can be connected to two or more base stations, each of which can support a set of cells to provide radio resources for communicating with the UE. SUMMARY

[0004] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0005] One innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication at an apparatus of a user equipment (UE), comprising: receiving, from a first base station, one or more reference signals; performing one or more radio resource management (RRM) measurements based on the one or more reference signals; and transmitting, to a second base station, information about the one or more RRM measurements.

[0006] Another innovative aspect of the subject matter described in this disclosure can be implemented in a user equipment, comprising: a wireless transceiver; and a processor configured to: receive, via the wireless transceiver, one or more reference signals from a first base station; perform one or more radio resource management (RRM) measurements based on the one or more reference signals; and transmit, via the wireless transceiver, information about the one or more RRM measurements to a second base station.

[0007] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus that includes means for receiving one or more reference signals from a first base station; means for performing one or more radio resource management (RRM) measurements based on the one or more reference signals; and means for transmitting information about the one or more RRM measurements to a second base station.

[0008] Another innovative aspect of the subject matter described in this disclosure relates to a non-transitory computer-readable medium storing computer-executable code including code for causing a processor in a user equipment to: receive one or more reference signals from a first base station; perform one or more radio resource management (RRM) measurements based on the one or more reference signals; and transmit information about the one or more RRM measurements to a second base station.

[0009] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication system that includes: a first base station; a second base station; and a user equipment configured to: receive one or more reference signals from the first base station; perform one or more radio resource management (RRM) measurements based on the one or more reference signals; and transmit information about the one or more RRM measurements to the second base station.

[0010] Another innovative aspect of the subject matter described in this disclosure relates to a method for wireless communication at an apparatus of a user equipment (UE), comprising: receiving one or more reference signals from a first base station; performing one or more channel quality indicator (CQI) measurements based on the one or more reference signals; storing information about the one or more CQI measurements; and transmitting the stored information about the one or more CQI measurements to the first base station or a second base station.

[0011] Another innovative aspect of the subject matter described in this disclosure can be implemented in a user equipment that includes: a memory; a wireless transceiver; and a processor configured to: receive one or more reference signals from a first base station via the wireless transceiver; perform one or more channel quality indicator (CQI) measurements based on the one or more reference signals; store information about the one or more CQI measurements in the memory; and transmit the stored information to the first base station or a second base station via the wireless transceiver.

[0012] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus that includes means for receiving one or more reference signals from a first base station; means for performing one or more channel quality indicator (CQI) measurements based on the one or more reference signals; means for storing information about the one or more CQI measurements; and means for transmitting the stored information about the one or more CQI measurements to the first base station or a second base station.

[0013] Another innovative aspect of the subject matter described in this disclosure relates to a non-transitory computer-readable medium storing computer-executable code including code for causing a processor in a user equipment to: receive one or more reference signals from a first base station; perform one or more channel quality indicator (CQI) measurements based on the one or more reference signals; store information about the one or more CQI measurements; and transmit the stored information about the one or more CQI measurements to the first base station or a second base station.

[0014] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication system that includes: a first base station; a second base station; and a user equipment configured to: receive one or more reference signals from the first base station; perform one or more channel quality indicator (CQI) measurements based on the one or more reference signals; store information about the one or more CQI measurements; and transmit the stored information about the one or more CQI measurements to the first base station or the second base station.

[0015] Another innovative aspect of the subject matter described in this disclosure relates to a method of wireless communication at an apparatus of a first base station, including: receiving, from a user equipment (UE), information associated with one or more channel quality indicator (CQI) measurements related to a second base station; and transmitting the information to the second base station.

[0016] Another innovative aspect of the subject matter described in this disclosure can be implemented in a base station that includes: a wireless transceiver; a backhaul interface; and a processor configured to: receive, from a user equipment (UE) via the wireless transceiver, information associated with one or more channel quality indicator (CQI) measurements related to another base station; and transmit, to the second base station via the backhaul interface, the information.

[0017] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus that includes: means for receiving, from a user equipment (UE), information associated with one or more channel quality indicator (CQI) measurements related to a second base station; and means for transmitting the information to the second base station.

[0018] Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium storing computer-executable code including code to cause a processor in a user equipment (UE) to: receive, from a first base station, information associated with one or more channel quality indicator (CQI) measurements related to the first base station; and transmit, to the first base station, the information.

[0019] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication system including: a user equipment; a first base station; a second base station, the second base station configured to: receive, from the user equipment, information associated with one or more channel quality indicator (CQI) measurements related to the first base station; and transmit, to the first base station, the information.

[0020] The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures can not be drawn to scale. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A diagram showing an example wireless radio access network.

[0022] Figure 2 A diagram showing an example organization of wireless communication link resources in an air interface utilizing orthogonal frequency division multiplexing (OFDM).

[0023] Figure 3 An example cellular communication system is shown.

[0024] Figure 4 An example flow diagram of a method for power efficient handover operations for a cellular communication system is shown. Figure 3

[0025] Figure 5 An example flow diagram of a method for power efficient link adaptation operations for a cellular communication system is shown. Figure 3

[0026] Figure 6 An example flow diagram of a method for another power efficient link adaptation operation for a cellular communication system is shown. Figure 3

[0027] Figure 7 A block diagram showing an example hardware implementation of a base station.

[0028] Figure 8 ​​​An example flow diagram illustrating a method for reporting, by a master base station, information to a secondary base station regarding channel quality indicator (CQI) measurements performed by a user equipment (UE) based on reference signals received from the secondary base station for link adaptation purposes.

[0029] Figure 9 A block diagram illustrating an example hardware implementation of a user equipment (UE).

[0030] Figure 10 An example flow diagram illustrating a method for reporting, by a user equipment (UE), radio resource management (RRM) measurements performed by the UE based on reference signals received from a secondary base station to a master base station.

[0031] Figure 11 An example flow diagram illustrating a method for reporting, by a user equipment (UE), radio resource management (RRM) measurements performed by the UE based on reference signals received from a secondary base station to a master base station.

[0032] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION

[0033] For purposes of describing the innovative aspects of the disclosure, the following description relates to certain implementations. A person skilled in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. Some examples in this disclosure are based on wireless and wired local area network (LAN) communications according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standards, IEEE 802.3 Ethernet standards, and IEEE 1901 power line communication (PLC) standards. The described implementations can be implemented in any device, system or network that is capable of transmitting and receiving RF signals according to any of the wireless communication standards, including any of the IEEE 802.11 standards, the Bluetooth® wireless personal area networks (WPANs), code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiplexing (OFDM), orthogonal frequency division modulation (OFDM), global system for mobile communications (GSM), voice over Internet protocol (VoIP), voice over new radio (VoNR), 3GPP, 5G, 5G NR, LTE, LTE-A, and / or any other wireless communication standard, protocol or technology. Standard, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), GSM, or General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA), Evolution Data Optimized (EV-DO), 1xEV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA), High

[0034] In one aspect, a user equipment (UE) connected to a master base station or node (MN) and a secondary base station or node (SN) can operate in a power efficient state associated with a secondary cell group (SCG) of the SN, which can include a primary cell (PScell) and one or more secondary cells (SScells). For example, in a deactivated state, the UE does not perform data transmission with the SN, does not monitor a physical downlink control channel (PDCCH) associated with the SN, and does not perform channel quality indicator (CQI) measurements with respect to the SN. In a dormant state, the UE does not perform data transmission with the SN and does not monitor a physical downlink control channel (PDCCH) associated with the SN, but does perform channel quality indicator (CQI) measurements with respect to the SN. These states are low power consumption states as compared to an active state in which the UE monitors a PDCCH for data to be transmitted by the SN to the UE and receives data from the SN.

[0035] In another aspect, the UE operates in a manner that ensures coverage by the SN in the deactivated or dormant state. In this regard, the UE performs radio resource management (RRM) measurements associated with the SCG or SN while in the dormant or deactivated state and reports these measurements to the MN. The RRM measurements are used by the MN to determine whether to implement a handover with respect to the PSCell of the SN or the SCG. Thus, the purpose of the RRM measurements is to ensure continued coverage of the SN. If the RRM measurements indicate that coverage is being lost, the MN can command the UE to perform a PSCell change or SN change based on the RRM measurements.

[0036] In yet another aspect, the UE operates in a manner that reduces the delay between transitioning from the dormant state to the active state. In this aspect, the UE performs channel quality indicator (CQI) measurements with respect to the SCG or SN while in the dormant state and stores the measurements for subsequent reporting to the SN (directly or via the MN) when the UE transitions to the active state. The CQI measurements are used by the SN to perform link adaptation (such as selecting a modulation coding scheme (MCS)) for data radio bearers (DRBs) to the UE. Thus, when the UE enters the active state, the delay can be relatively small because the SN already has the link adaptation information.

[0037] Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. For example, when the UE does not receive data from the SN or transmit data to the SN, the UE can be able to operate in a deactivated or dormant state in which the UE does not consume power to monitor a physical downlink control channel (PDDCH) for data transmitted by the SN, thereby saving power. Additionally, in the deactivated or dormant state, by having the UE report RRM measurements with respect to the SN to the MN, the SN can ensure coverage when data is to be transmitted to the UE by the SN. Moreover, in the dormant state, the UE can report CQI measurements directly or via the MN to the SN so that the SN can perform link adaptation (such as selecting a modulation coding scheme (MCS)) when data is to be transmitted to the UE after the UE transitions from the dormant state to the active state; thereby reducing the delay for the UE to receive the data.

[0038] The various concepts presented throughout this disclosure can be implemented across a wide variety of telecommunications systems, network architectures, and communication standards.

[0039] Figure 1 A diagram illustrates an example wireless radio access network 100 (e.g., a wireless communication system). The RAN 100 can implement any suitable wireless communication technology or technologies to provide radio access. As one example, the RAN 100 can operate according to 3rd Generation Partnership Project (3GPP) New Radio (NR) specifications, often referred to as 5G. As another example, the RAN 100 can operate according to a hybrid of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, often referred to as LTE. The 3GPP refers to this hybrid RAN as a Next Generation RAN, or NG-RAN. Of course, many other examples can be utilized within the scope of the present disclosure.

[0040] The geographic region covered by the radio access network 100 can be divided into a number of cellular regions (cells), with a user equipment (UE) capable of operating in any of the regions. A Figure 1Macro cells 102, 104 and 106, and a small cell 108 are shown, wherein each can include one or more sectors (not shown). A sector is a sub-area of a cell. All sectors within a cell are served by the same base station. A radio or communication link in a sector can be identified by a single logical name belonging to that sector. In a cell divided in sectors, multiple sectors within a cell can be formed by antenna groups, where each antenna is responsible for the communication with UEs in a part of the cell.

[0041] Generally, a respective base station (BS) serves each cell. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception to and from UEs within one or more cells. A BS can also be referred to by those skilled in the art as a base station transceiver (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a NodeB (NB), an evolved NodeB (eNB), a g NodeB (gNB), or some other suitable terminology.

[0042] In Figure 1 , two base stations 110 and 112 are shown as serving cells 102 and 104, respectively; and a third base station 114 is shown as controlling a remote radio head (RRH) 116 in cell 106. That is, a base station can have integrated antennas, or can be connected by feeders to antennas or RRHs. In the illustrated example, cells 102, 104 and 106 can be referred to as macro cells because base stations 110, 112 and 114 support cells with large sizes. Further, base station 118 is shown as serving a small cell 108, such as a microcell, picocell, femtocell, home base station, home NodeB, home evolved NodeB, etc., which can overlap with one or more macro cells. In this example, cell 108 can be referred to as a small cell because base station 118 supports a cell with a relatively small size. Cell size setting can be done according to system design and component constraints. It is to be understood that the radio access network 100 can include any number of wireless base stations and cells. Further, a relay node or UE can be deployed to extend the size or coverage area of a given cell, or to provide an additional connection for load balancing and / or diversity. Base stations 110, 112, 114 and 118 provide wireless access points to a core network for any number of mobile apparatuses.

[0043] Figure 1Also included are quadcopters or drones 120, which can be configured to act as base stations. That is, in some examples, a cell can not necessarily be stationary, and the geographic area of a cell can move with the location of a mobile base station, such as quadcopter 120.

[0044] Generally, a base station can include a backhaul interface for communication with a backhaul portion of a network (not shown). The backhaul can provide a link between a base station and a core network (not shown), and in some examples, the backhaul can provide interconnection between respective base stations. The core network can be part of a wireless communication system, and can be independent of the radio access technology used in the radio access network. Various types of backhaul interfaces can be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network.

[0045] The RAN 100 is shown to include a plurality of base stations 110 and 115. A base station is generally a fixed station that communicates with the UEs and can also be referred to as, and can include some or all of the functionality of, an access point, a broadcast receiver, a Node-B, an eNode B, a gNode B, a Home Node B, a Home eNode B, a gNB, or some other suitable terminology. A base station can provide wireless communication coverage for a particular area to allow UEs to access the cellular network. A base station can also be more generally referred to as a transmit receive point (TRP). Base stations 110 can be implemented as network access devices configured to provide a access to a core network for UEs. Base stations 115 can be implemented as network access devices configured to provide access to a core network for UEs. Base stations 110 and 115 can be associated with a same or different operator, respectively, and can be located in a same or different geographic regions. The base stations 110 and 115 can communicate with one another, for example, over a wired or wireless backhaul connection. The base stations 110 and 115 can communicate with the core network 130, for example, over wired or wireless backhaul connections.

[0046] In the document, a “mobile” device can not necessarily have a capability to move and can be stationary. The term mobile device or mobile equipment refers broadly to various devices and technologies. For example, some non-limiting examples of a mobile device include a mobile station, a cellular (cell) phone, a smartphone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC), a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA), and a broad array of embedded systems, such as those associated with the “Internet of Things” (IoT). A mobile device can additionally be an automobile or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer electronics device, or a wearable device, such as a watch, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player), a camera, a game console, etc.

[0047] The mobile device can additionally be a digital home or smart home device, such as a home audio, video or multimedia device, an appliance, a vending machine, smart lighting, a home security system, a smart meter, and the like. The mobile device can additionally be a smart energy device, a security device, a solar panel or solar array, a control for electrical power, municipal infrastructure such as a smart grid, lighting, water, and the like; industrial automation and enterprise devices; logistics controllers; agricultural devices; military defense devices, vehicles, aircraft, watercraft, and weaponry, and the like. Still further, the mobile device can provide connected medical or telemedicine support (i.e., healthcare at a distance). Telehealth devices can include remote medical monitoring devices and remote medical management devices, whose communications can be given priority treatment or priority access over other types of information, such as priority access for or related QoS for transmissions of critical service data.

[0048] Within the RAN 100, a cell can include UEs that can be in communication with one or more sectors in each cell. For example, UEs 122 and 124 can be in communication with base station 110; UEs 126 and 128 can be in communication with base station 112; UEs 130 and 132 can be in communication with base station 114 through RRH 116; UE 134 can be in communication with base station 118; and UE 136 can be in communication with mobile base station 120. Here, each base station 110, 112, 114, 118, and 120 can be configured to provide an access point to a core network (not shown) for all UEs in the respective cells. In another example, a mobile network node such as quadcopter 120 can be configured to act as a UE. For example, quadcopter 120 can operate within cell 102 by communicating with base station 110.

[0049] Wireless communication between the RAN 100 and a UE, such as UE 122 or 124, can be described as utilizing an air interface. Transmissions from a base station, such as base station 110, to one or more UEs, such as UEs 122 and 124, can be referred to as downlink (DL) transmission. In accordance with certain aspects of the present disclosure, the term downlink can refer to point-to-multipoint transmission originating at a scheduling entity (further described below; such as base station 110). Another way to describe this scheme can be to use the term broadcast channel multiplexing. Transmissions from a UE, such as UE 122, to a base station, such as base station 110, can be referred to as uplink (UL) transmission. In accordance with further aspects of the present disclosure, the term uplink can refer to point-to-point transmission originating at a scheduled entity (further described below; such as UE 122).

[0050] For example, a DL transmission can include unicast or broadcast transmissions of control information or traffic information (such as user data traffic) from a base station (such as base station 110) to one or more UEs (such as UEs 122 and 124), while a UL transmission can include transmissions of control information and / or traffic information originating at UEs (such as UE 122). Additionally, the uplink or downlink control information and / or traffic information can be time-divided into frames, subframes, slots or symbols. As used herein, a symbol can refer to a time unit that carries one resource element (RE) per subcarrier in an orthogonal frequency-division multiplexing (OFDM) waveform. A slot can carry 7 or 14 OFDM symbols. A subframe can refer to a duration of 1ms. Multiple subframes or slots can be grouped together to form a single frame or radio frame. Of course, these definitions are not required, and any suitable scheme for organizing waveforms can be utilized, and various time divisions of the waveforms can have any suitable duration.

[0051] The air interface in the RAN 100 can utilize one or more multiplex and multiple access algorithms to enable simultaneous communication with multiple devices. For example, 5G NR specifications utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (hereinafter also referred to as “CP-OFDM”) providing multiplexing and multiple access for UL or reverse link transmissions from a UE 122 and 124 to a base station 110, as well as for DL or forward link transmissions from the base station 110 to the UEs 122 and 124. Additionally, for UL transmissions, 5G NR specifications provide support for discrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (also referred to as single-carrier FDMA (SC-FDMA)). However, multiplexing and multiple access are not limited to the above schemes, and can be provided utilizing time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), sparse code multiple access (SCMA), resource spread multiple access (RSMA), or other suitable multiple access schemes. Further, multiplexing for DL transmissions from the base station 110 to the UEs 122 and 124 can be provided utilizing time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), or other suitable multiplexing schemes.

[0052] Further, the air interface in the RAN 100 can utilize one or more duplexing algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another. Full-duplex means both endpoints can simultaneously communicate with one another. Half-duplex means only one endpoint can send information to the other endpoint at a time. In a wireless link, full-duplex channels generally rely on physical isolation between transmitter and receiver, as well as suitable interference cancellation technologies. Full-duplex emulation is often achieved through utilization of frequency-division duplex (FDD) or time-division duplex (TDD). In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions are separated from one another using time division multiplexing. That is, at some times the channel is dedicated to transmissions in one direction, while at other times the channel is dedicated to transmissions in the other direction, where the direction can change very rapidly, such as several times a slot.

[0053] In the RAN 100, the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels are typically established, maintained, and released under the control of an access and mobility management function (AMF), which can include a security context management function (SCMF) that manages the security context for both the control plane and the user plane functions, and a security anchor function (SEAF) that performs authentication. In various aspects of the disclosure, the RAN 100 can utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE’s connection from one radio channel to another). In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE can monitor various parameters of the signal from its serving cell and various parameters of neighboring cells.

[0054] Depending on the quality of these parameters, the UE can maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if the signal quality from a neighboring cell exceeds the signal quality from the serving cell for a given amount of time, the UE can undergo a transition or handover from the serving cell to the neighboring (target) cell. For example, the UE 124 can move from the geographic area corresponding to its serving cell 102 to the geographic area corresponding to the neighboring cell 106. When the signal strength or quality from the neighboring cell 106 exceeds that of its serving cell 102 for a given amount of time, the UE 124 can send a reporting message to its serving base station 110 indicating this condition. In response, the UE 124 can receive a handover command, and the UE can undergo a handover to cell 106.

[0055] In networks configured for UL-based mobility, the UL reference signals from each UE can be used by the network to select a serving cell for each UE. In some examples, the base stations 110, 112, and 114 / 116 can broadcast unified synchronization signals, such as a unified primary synchronization signal (PSS), unified secondary synchronization signal (SSS), and unified physical broadcast channel (PBCH). The UEs 122, 124, 126, 128, 130, and 132 can receive the unified synchronization signals, derive the carrier frequency and radio frame timing from the synchronization signals, and in response to deriving timing, transmit uplink pilot or reference signals. The uplink pilot signals transmitted by a UE, such as the UE 124, can be concurrently received by two or more cells in the RAN 100, such as the base stations 110 and 114 / 116. Each of these cells can measure a strength of the pilot signal, and the RAN, such as one or more of the base stations 110 and 114 / 116 and / or a central node in the core network, can determine a serving cell for the UE 124. As the UE 124 moves through the RAN 100, the network can continue to monitor the uplink pilot signals transmitted by the UE 124. When the signal strength or quality of the pilot signals measured by a neighbor cell exceeds that of the signal strength or quality measured by the serving cell, the RAN 100 can handover the UE 124 from the serving cell to the neighbor cell, with or without notifying the UE 124.

[0056] While the synchronization signals transmitted by the base stations 110, 112, and 114 / 116 can be unified, the synchronization signals can not identify a particular cell, but can instead identify a zone of multiple cells operating on the same frequency or with the same timing. The use of zones in 5G or other next generation communication networks enables the uplink-based mobility framework and improves the efficiency of both the UE and the network, as the number of mobility messages that need to be exchanged between the UE and the network can be reduced.

[0057] In various implementations, the air interface of the RAN 100 can utilize licensed spectrum, unlicensed spectrum, or shared spectrum. Licensed spectrum provides for exclusive use of a portion of the spectrum to a licensee on an ongoing basis. Unlicensed spectrum is available for use by any operator without the need for a government-issued license. While use of unlicensed spectrum is generally unregulated, access to the spectrum is still subject to certain rules and guidelines. For example, currently, use of the 5 GHz band is governed by the European Telecommunications Standards Institute (ETSI) in Europe, by the Federal Communications Commission (FCC) in the United States, and by Innovation, Science and Economic Development Canada (ISED) in Canada. In general, unlicensed spectrum can still require operators to employ similar technical regulations to access the spectrum, such as performing clear channel assessment (CCA) before transmitting. Shared spectrum can fall somewhere between licensed and unlicensed spectrum. For example, the holder of a license for a portion of the spectrum can provide licensed shared access (LSA) to share the spectrum with other parties, such as with suitable conditions determined by the licensee to gain access.

[0058] In some examples, access to the air interface can be scheduled, with a scheduling entity (such as a base station) allocating resources (for example, time-frequency resources) for communication among some or all devices and apparatuses within its service area or cell. Within the present disclosure, as discussed further below, a scheduling entity can be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, a UE or scheduled entity utilizes resources allocated by the scheduling entity.

[0059] A base station is not the only entity that can act as a scheduling entity. That is, in some examples, a UE can act as a scheduling entity, scheduling resources for one or more scheduled entities, such as one or more other UEs. In this example, sidelink or other types of direct link signals can be transmitted directly between UEs without relying on scheduling or control information from another entity, e.g., a base station. For example, UE 138 is shown in communication with UEs 140 and 142. In some examples, UE 138 acts as a scheduling entity, while UEs 140 and 142 can act as scheduled entities. For example, UE 138 can act as a scheduling entity in a device-to-device (D2D), peer-to-peer (P2P), vehicle-to- everything (V2X), or mesh network. In a mesh networking example, UEs 140 and 142 can optionally communicate directly with one another in addition to communicating with the scheduling entity 138.

[0060] In some other examples, two or more UEs (e.g., UEs 126 and 128) within the coverage area of a serving base station 112 can communicate with the base station 112 using cellular signals and can communicate with one another using direct link (e.g., sidelink) signals 127 without relaying this communication through the base station. In an example of a V2X network within the coverage area of the base station 112, the base station 112, or one or both of UEs 126 and 128 can act as a scheduling entity to schedule sidelink communications between UEs 126 and 128.

[0061] Sidelink communications 127 between UEs 126 and 128 or between UEs 138, 140, and 142 can occur through a Proximity Services (ProSe) PC5 interface. ProSe communications can support different operational scenarios, such as in-coverage, out-of-coverage, and partial-coverage. Out-of-coverage refers to a scenario in which a UE (e.g., UEs 138, 140, and 142) is outside of coverage of a base station (e.g., base station 146), but each UE is still configured for ProSe communications. Partial-coverage refers to a scenario in which one UE is outside of a coverage area of a base station, while one or more other UEs in communication with the UE are within the coverage area of the base station. In-coverage refers to a scenario in which UEs (e.g., UEs 126 and 128) are in communication with a base station (e.g., base station 112) via a Uu (e.g., cellular interface) connection to receive ProSe service authorization and provisioning information to support ProSe operations.

[0062] Reference will be made to the drawings in which: Figure 2Various aspects of the present disclosure are described in terms of example OFDM waveforms. One of ordinary skill in the art can readily understand that the various aspects of the present disclosure can be applied to SC-FDMA waveforms, substantially as described herein below. That is, while some examples of the present disclosure can focus on OFDM links for clarity, it will be understood that the same principles apply to SC-FDMA waveforms as well.

[0063] Figure 2 A diagram illustrating an example organization of wireless communication link resources in an orthogonal frequency division multiplexing (OFDM) air interface is shown. An expanded view of an example subframe 202 is shown, showing an OFDM resource grid. However, as those skilled in the art will appreciate, the PHY transmission structure for any particular application can differ from this example in many respects, depending on

[0064] The resource grid 204 can be used to represent time-frequency resources for a given antenna port. That is, in a multiple-input multiple-output (MIMO) implementation with multiple available antenna ports, a corresponding multiple of resource grids 204 can be available for communication. The resource grid 204 is divided into multiple resource elements (REs) 206. An RE, which is 1 subcarrier x 1 symbol, is the smallest discrete part of the time-frequency grid, and contains a single complex value representing data from a physical channel or signal. Depending on the modulation, each RE can represent one or more bits of information. In some examples, a block of REs can be referred to as a physical resource block (PRB) or more simply a resource block (RB) 208, which contains any suitable number of consecutive subcarriers in the frequency domain. In one example, an RB can include 12 subcarriers, a number independent of the numerology used. In some examples, depending on the numerology, an RB can include any suitable number of consecutive OFDM symbols in the time domain. Within the present disclosure, it is assumed that a single RB (such as the RB 208) corresponds to a single direction of communication (either transmission or reception for a given device) at a time.

[0065] Scheduling a UE device for downlink, uplink, or sidelink transmission typically involves scheduling one or more resource elements 206 within one or more subbands. Therefore, the UE device typically utilizes only a subset of the resource grid 204. In some examples, an RB can be the smallest unit of resource that can be allocated to the UE device. Therefore, the more RBs scheduled for the UE device, and the more sophisticated the modulation scheme selected for the air interface, the higher the data rate for the UE device. RBs can be scheduled by the base station (e.g., gNB, eNB, RSU, etc.) or can be self-scheduled by the UE implementing D2D sidelink communication.

[0066] In this illustration, RB 208 is shown occupying less than the entire bandwidth of subframe 202, with some subcarriers shown above and below RB 208. In a given implementation, subframe 202 can have a bandwidth corresponding to any number of one or more RB 208s. Furthermore, while RB 208 is shown occupying less than the entire duration of subframe 202 in this illustration, this is merely one possible example.

[0067] Each 1-millisecond (ms) subframe 202 can consist of one or more adjacent time slots. Figure 2 In the example shown, a subframe 202 includes four time slots 210, as an illustrative example. In some examples, time slots can be defined based on a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a time slot may include 7 or 14 OFDM symbols with a nominal CP. Other examples may include micro-time slots with shorter durations (e.g., one to three OFDM symbols). In some cases, these micro-time slots may be transmitted, occupying resources scheduled for ongoing time slot transmissions for the same or different UEs. Any number of resource blocks within a subframe or time slot can be utilized.

[0068] An expanded view of time slot 210 shows that time slot 210 includes a control region 212 and a data region 214. Typically, control region 212 may carry control channels, and data region 214 may carry data channels. Of course, a time slot may contain all DL, all UL, or at least one DL portion and at least one UL portion. Figure 2 The simple structure shown is merely an example, and different time slot structures can be used, which may include one or more regions in each of the control and data regions.

[0069] Despite Figure 2Although not shown, various REs 206 within the RB 208 can be scheduled to carry one or more physical channels, including control channels, shared channels, data channels, etc. Other REs 206 within the RB 208 can also carry pilots or reference signals, including but not limited to a demodulation reference signal (DMRS), a control reference signal (CRS), or a sounding reference signal (SRS). These pilots or reference signals can provide for a receiving device to perform channel estimation, which can enable coherent demodulation / detection of control or data channels within the RB 208.

[0070] In some examples, the slot 210 can be used for broadcast or unicast communications. In a V2X or D2D network, a broadcast communication can refer to a point-to-multipoint transmission by one device (e.g., a vehicle, a base station (e.g., RSU, gNB, eNB, etc.), UE, or other similar device) to other devices. A unicast communication can refer to a point-to-point transmission by one device to a single other device.

[0071] In examples of cellular communications over a cellular carrier via a Uu interface, for DL transmissions, a scheduling entity (e.g., a base station) can assign one or more REs 206 (e.g., within the control region 212 of the slot 210) to carry DL control information including one or more DL control channels (such as, for example, a SSB, a PDCCH) to one or more scheduled entities (e.g., UEs), which can include one or more sidelink devices (such as V2X / D2D devices). The PDCCH carries downlink control information (DCI), which includes, for example, scheduling information that provides a grant for DL and UL transmissions and RE allocation.

[0072] In UL transmissions over a Uu interface, a scheduled entity can utilize one or more REs 206 to carry UL control information (UCI) including one or more UL control channels (such as, for example, a physical uplink control channel (PUCCH)) to the scheduling entity. The UCI can include, for example, pilots, reference signals, and information that enables or assists in decoding of uplink data transmissions. In some examples, the UCI can include a scheduling request (SR), i.e., a request for the scheduling entity to schedule uplink transmissions.

[0073] In addition to control information, one or more REs 206 can be allocated for user data services (e.g., within data area 214). Such services can be carried on one or more service channels, such as the Physical Downlink Shared Channel (PDSCH) for DL ​​transmissions or the Physical Uplink Shared Channel (PUSCH) for UL transmissions. In some examples, one or more REs 206 can be configured to carry System Information Blocks (SIBs), which contain information enabling access to a given cell.

[0074] In an example of sidelink communication on a sidelink carrier via the PC5 interface, the control area 212 of the time slot may include control information transmitted by the sidelink device on the sidelink channel, while the data area 214 of the time slot 210 may include data transmitted by the sidelink device on the sidelink channel. In some examples, the control information may be transmitted within the sidelink control information (SCI) on the physical sidelink control channel (PSCCH), while the data may be transmitted within the physical sidelink shared channel (PSSCH). For in-coverage or partial-coverage scenarios, the DCI transmitted by the base station on the Uu interface may include scheduling information indicating one or more resource blocks within the control area 212 or data area 214 allocated to the sidelink device for sidelink communication.

[0075] The physical channels described above are typically multiplexed and mapped to transport channels for processing at the Media Access Control (MAC) layer. The transport channels carry blocks of information called transport blocks (TBs). The transport block size (TBS) (which can correspond to the number of information bits) can be a controlled parameter based on the modulation and coding scheme (MCS) and the number of redundancies (RBs) in a given transmission.

[0076] exist Figure 2 The channels or carriers shown are not necessarily all channels or carriers that can be used between devices, and those skilled in the art will recognize that other channels or carriers, such as other service, control, and feedback channels, can be used in addition to the channels or carriers shown.

[0077] Figure 3 An example cellular communication system 300 is shown. As discussed in more detail herein, in a multiple radio access technology (RAT) dual connectivity configuration, a user equipment (UE) has simultaneous connections (signaling and data radio bearers) to both a primary base station (also referred to as a "primary node (MN)") and a secondary base station (also referred to as a "secondary primary node (SN)").

[0078] Dual connectivity provides many advantages, such as increased data rates due to the UE using radio resources from both the primary base station and the secondary base station; increased reliability due to the secondary base station providing another data pipe that can be used to transmit data between the core of the cellular network and the UE; improved load balancing between different base stations of the cellular communication system; improved deployment of NR base stations and use of existing LTE cellular communication system infrastructure; and reuse of LTE cellular communication infrastructure to implement NR base stations and other infrastructure.

[0079] As discussed herein, a UE can operate in a power-efficient manner with respect to a secondary base station, especially when no data is being communicated between the secondary base station and the UE. For example, the UE can be in a "deactivated" operating state associated with the SCG of the secondary base station, which is characterized by: (1) no data transmissions occurring between the secondary base station and the UE; (2) the UE not monitoring physical downlink control channel (PDCCH) signals transmitted by the secondary base station; and (3) the UE not performing channel quality indicator (CQI) measurements on a channel between the secondary base station and the UE. By not performing data transmissions, not monitoring PDCCH signals, and not performing CQI measurements, the UE conserves a significant amount of power, such that the UE operates in a power-efficient manner.

[0080] In another example, the UE can be in a "dormant" operating state associated with the SCG of the secondary base station, which is characterized by: (1) no data transmissions occurring between the secondary base station and the UE; (2) the UE not monitoring physical downlink control channel (PDCCH) signals transmitted by the secondary base station; and (3) the UE performing CQI measurements based on reference signals received from the secondary base station. Although in the dormant operating state, the UE consumes more power than when in the deactivated operating state (due to the CQI measurements), the UE still operates in a power-efficient manner because it does not monitor PDCCH signals and can not maintain uplink (UL) timing with the secondary base station.

[0081] When data is to be transmitted between the secondary base station and the UE, the UE transitions from the deactivated or dormant state to an "active" operating state associated with the SCG of the secondary base station. In the active state, the UE monitors PDCCH signals to determine whether there is data transmitted from the secondary base station to the UE, in which resource block(s) (RBs) the data is located, and link adaptation information (e.g., modulation and coding scheme (MCS) used to transmit the data); and also maintains UL link timing in the case that some type of automatic repeat request (ARQ) message is used. Due to the additional tasks that the UE needs to perform in the active operating state, the UE consumes more power in the active state than in the deactivated or dormant state. Thus, if no data is communicated between the secondary base station and the UE, the UE can operate in the deactivated or dormant state to conserve power. With respect to the primary base station, the UE operates in the active state to prevent delay in the exchange of data and signaling between the UE and the cellular core network via the primary base station.

[0082] In addition to the operating states described above with respect to the secondary base station (deactivated, dormant, and active states), the UE also performs operations to ensure that it is covered by the SN in the deactivated or dormant state. One operation is to perform one or more radio resource management (RRM) measurements based on one or more reference signals received from the secondary base station while the UE is in the deactivated or dormant state.

[0083] The RRM measurements can include one or more of the following: reference signal received power (RSRP) measurements, reference signal received quality (RSRQ) measurements, carrier received signal strength indicator (RSSI), and signal to interference noise ratio (SINR). If the secondary base station supports a set of cells (also referred to as a secondary cell group (SCG)), the UE can perform RRM measurements based on reference signals generated by the cells of the SCG, respectively. The UE can also perform RRM measurements based on reference signals generated by candidate secondary base stations. As examples, the reference signals can be channel state information reference signals (CSI-RS) or signal synchronization block (SSB) signals from each secondary base station or a cell in the SCG supported by the base station. The RRM measurements are used to make handover decisions with respect to the secondary base station, e.g., changing the secondary base station assigned to the UE or changing the primary secondary cell (PSCell) of the SCG. The PSCell is the cell for which the UE performs an attach or reattach procedure. Other cells in the SCG can be used in conjunction with the PSCell for carrier aggregation (CA) to increase the data rate between the secondary base station and the UE.

[0084] Further, in accordance with the RRM measurement operation when the UE is in the deactivated or dormant operating state, the UE sends information about the RRM measurements to the primary base station. The primary base station can use this information to determine whether a change or handover is needed with respect to the secondary base station assigned to the UE or the PSCell assigned to the UE. If such a change or handover is needed, the primary base station generates appropriate signaling to initiate the change or handover. Thus, when the operating state of the UE transitions from the deactivated or dormant state to the active state, the appropriate secondary base station and PSCell are used for transmission of data between the secondary base station and the UE.

[0085] Another operation performed by the UE to reduce the delay in transitioning from the dormant state to the active state in a power efficient manner is to store or buffer CQI measurements based on reference signals received from the secondary base station and send the CQI measurements to the secondary base station after entering the active state. The CQI measurements, which are an indication of the signal to interference plus noise ratio (SINR), can be based on CSI-RS reference signals transmitted by the secondary base station or the cells of the SCG of the secondary base station. The CQI measurements are useful in link adaptation when data is to be transmitted between the second base station and the UE (e.g., selecting an appropriate MCS based on the channel conditions as indicated by the CQI measurements). Thus, when the UE enters the active state and sends information about the CQI measurements to the secondary base station, the secondary base station is able to quickly perform link adaptation to send data to the UE.

[0086] Another operation performed by the primary base station to reduce the delay between the UE transitioning from the dormant operating state to the active operating state is for the primary base station to forward information about CQI measurements performed by the UE with respect to the secondary base station while the UE was in the dormant state to the secondary base station via the signaling link. Having this information at hand when the UE enters the active state allows the secondary base station to quickly perform link adaptation (e.g., select an MCS for data) and send data to the UE based on the link adaptation. The above-mentioned operating states and procedures for reducing the delay between the UE operating in the deactivated state or the dormant state and changing to the active state are discussed in more detail below with respect to the cellular or wireless communication system 300 shown in FIG. 3. Figure 3

[0087] ​The cellular communication system 300 includes a user equipment (UE) 310, a primary base station or MN 320, and a secondary base station or SN 330. The primary base station 320 can support a set of cells 325-1 through 325-M (where M can be one or more), commonly referred to as a master cell group (MCG). The cells of the MCG 325-1 through 325-M can transmit and receive data and signaling to and from the UE 310 using different radio frequency (RF) carriers (e.g., in the case of carrier aggregation (CA)). Similarly, the secondary base station 330 can support a set of cells 335-1 through 325-N (where N can be one or more), commonly referred to as a secondary cell group (SCG). The cells of the SCG 335-1 through 335-N can transmit and receive data and signaling to and from the UE 310 using different radio frequency (RF) carriers (e.g., in the case of carrier aggregation (CA)).

[0088] The cellular communication system 300 also includes a mobility management equipment (MME) 340 and a serving gateway (SG) 350. While the MME 340 performs many functions, the MME 340 is responsible for tracking the location of UEs, paging and authenticating UEs. The SG 350 is responsible for forwarding data packets between packet gateways connected to the Internet or other networks and base stations. Although not shown, the cellular communication system 300 can include additional infrastructure, such as packet gateways, a home subscriber server (HSS), a charging server, etc.

[0089] There are various control plane and user plane links between the various network components of the cellular communication system 300. As shown in FIG. 3, Figure 3 The control plane links are shown as dashed lines between the network components and the user plane links are shown as solid lines between the components. The control plane links are used to transmit control signals or signaling. The user plane links are used to transmit data from or to the UE via one or more network components. For example, the cellular communication system 300 includes a control plane link 342 (e.g., S1-MME) between the MME 340 and the primary base station 320; a control plane link 344 (e.g., S11) between the MME 340 and the SG 350; a control plane link 322 (e.g., Xn / X2) and a user plane link 324 (X2-U) between the primary base station 320 and the secondary base station 330; a user plane link 352 (e.g., S1-U) between the SG 350 and the primary base station 320; and can include a user plane link 358 (e.g., S1-U) between the SG 350 and the secondary base station 330, but in some implementations, the secondary base station receives user data via the user plane link 324.

[0090] In this example, UE 310 is connected to primary base station 320 via signaling radio bearer (SRB) 312 and data radio bearer (DRB) 314. SRB 312 is used to transmit control signals from primary base station 320 to UE 310 via downlink (DL) transmission and from UE 310 to primary base station 320 via uplink (UL) transmission. Similarly, UE 310 is connected to secondary base station 330 via signaling radio bearer (SRB) 316 and data radio bearer (DRB) 318. SRB 316 is used to transmit control signals from secondary base station 330 to UE 310 via downlink (DL) transmission and from UE 310 to secondary base station 330 via uplink (UL) transmission.

[0091] Since UE 310 is connected to two base stations 320 and 330, the UE is referred to as being in a multi-LTE dual-connectivity configuration. As previously discussed, dual-connectivity configurations offer several advantages, including higher data rates, increased reliability, load balancing, and the ability to roll out NR over existing LTE networks. As indicated by the advantages described last, cellular communication system 300 can include a hybrid of LTE and NR infrastructure. For example, in the case of EUTRA-NR (EN-DC) dual connectivity, the primary base station 320 can be an LTE base station (e.g., a primary eNB (MeNB)) and the secondary base station can be an NR base station (e.g., an En-gNB). In some other implementations, the primary base station 320 can be an NR base station and the secondary base station 330 can be an LTE base station. In other implementations, the primary base station 320 and the secondary base station 330 can be of the same type, both being LTE base stations or both being NR base stations.

[0092] Figure 4 Showing the use of Figure 3 An example flowchart of a method 400 for power-efficient handover operation of a cellular communication system is provided. Method 400 is described with reference to the previously described cellular communication device 300. In method 400, the UE 310 is in a deactivated or dormant operating state. That is, in both states, the UE 310 does not receive data from the secondary base station 330 and does not monitor any PDCCH signals transmitted by the secondary base station 330.

[0093] In the deactivated state, the UE 310 does not perform CQI measurements based on reference signals transmitted by the secondary base station 330. In the dormant state, the UE 310 performs CQI measurements based on reference information transmitted by the secondary base station 330, and can report the CQI measurements to the secondary base station 330 after entering the active state (optionally via the primary base station 320), or can report the CQI measurements to the primary base station 320 while the UE 310 is operating in the dormant state. When operating in the deactivated or dormant state, the UE 310 consumes less power than it would otherwise consume while operating in the active state. Moreover, as discussed, the UE 310 can be in a dual connectivity configuration in which the UE is connected to the primary base station 320 and the secondary base station 330.

[0094] The method 400 includes the secondary base station 330 transmitting one or more reference signals (block 402). In some implementations, the one or more reference signals can each be a CSI-RS, an SSB, or other reference signal. In some implementations, if the secondary base station 330 supports an SCG, then a set of the cells 335-1 through 335-N in the SCG respectively transmit the reference signals.

[0095] The method 400 also includes the UE 310 receiving the one or more reference signals (block 404) and performing one or more RRM measurements based on the one or more reference signals (block 406). In some implementations, the one or more RRM measurements are based on a configuration for RRM measurements received from the secondary base station 330. In some implementations, each RRM measurement can include a measurement of one or more of: RSRP, RSRQ, RSSI, and SINR. In another implementation, if the secondary base station 330 includes a set of the cells 335-1 through 335-N in an SCG, then: in block 404, the UE 310 respectively receives a set of reference signals from the set of cells 335-1 through 355-N; and in block 406, the UE 310 respectively performs a set of RRM measurements based on the set of reference signals.

[0096] Method 400 further includes: UE 310 sending information about one or more RRMs to primary base station 320 (block 408). In some implementations, UE 310 sends the information to primary base station 320 via a signaling radio bearer (SRB). In another implementation, UE 310 sends the information to primary base station 320 via SRB1 as defined in the LTE or NR specification. In yet another implementation, when a second SRB for sending signaling from UE 310 to secondary base station 330 is present, UE 310 sends the information to primary base station 320 via a first SRB. In still another implementation, when an SRB3 for sending signaling from UE 310 to secondary base station 330 is present, UE 310 sends the information to primary base station 320 via SRB1, where SRB1 and SRB3 are defined in the LTE or NR specification. In another implementation, if the secondary base station 330 includes the set of cells 335-1 to 335-N in the SCG, then the UE 310 sends information about the set of RRM measurements to the primary base station 320.

[0097] Method 400 may further include: the primary base station 320 determining, based on RRM measurement information received from the UE, whether to change (switch) the current primary / secondary cell (PSCell) or secondary base station assigned to the UE (box 410). If the primary base station 320 decides to perform the change according to box 410, the primary base station 320 initiates the change of PSCell or secondary base station (box 412). In some implementations, this may require the primary base station 320 to provide signaling to the secondary base station 330 via control link 322, to the MME 340 via control link 342, and to the new secondary base station via another control link (not shown).

[0098] Figure 5 Showing the use of Figure 3 An example flowchart of a method 500 for power-efficient link adaptation operation of a cellular communication system is provided. Method 500 is described with reference to the previously described cellular communication device 300. In method 500, the UE 310 is in a sleep operation state. That is, the UE 310 does not receive data from the secondary base station 330, does not monitor the PDCCH signal transmitted by the secondary base station 330, and performs CQI measurements based on a reference signal transmitted by the secondary base station 330. When operating in the sleep state, the UE 310 consumes less power compared to when operating in the active state in other ways. Furthermore, as discussed, the UE 310 can be in a dual-connectivity configuration, wherein the UE is connected to both the primary base station 320 and the secondary base station 330.

[0099] The method 500 includes the secondary base station 330 transmitting one or more reference signals (block 502). In some implementations, the one or more reference signals can each be a CSI-RS, an SSB, or other reference signal. In some implementations, if the secondary base station 330 supports an SCG, then a set of the cells 335-1 through 335-N in the SCG respectively transmit the reference signals.

[0100] The method 500 also includes the UE 310 receiving the one or more reference signals (block 504) and performing one or more CQI measurements based on the one or more reference signals (block 506). In some implementations, the one or more CQI measurements are based on a configuration for CQI measurements received from the secondary base station 330. In some implementations, each CQI measurement can be based on a SINR measurement. In another implementation, if the secondary base station 330 includes a set of the cells 335-1 through 335-N in an SCG, then: in block 504, the UE 310 receives a set of reference signals from the set of cells 335-1 through 355-N, respectively; and in block 506, the UE 310 performs a set of CQI measurements based on the set of reference signals, respectively.

[0101] The method 500 also includes the UE 310 storing or buffering information about the one or more CQIs in internal memory (block 508). In one implementation, the UE 310 can store the information based on a parameter. For example, in one implementation, the parameter can specify a number of most recent CQI measurements to be stored or included for a subsequent transmission to the secondary base station 330. In another implementation, the parameter can specify a number of most recent CQI measurements made within a defined time interval to be stored or included for a subsequent transmission to the secondary base station 330.

[0102] Method 500 further includes: UE 310 sending information about one or more CQI measurements to secondary base station 330 (block 510). In some implementations, if UE 310 determines that it is not aligned with the uplink (UL) timing with secondary base station 330 when transitioning from a dormant state to an active state, UE 310 performs a random access channel (RACH) procedure with secondary base station 330 to regain UL timing. In another implementation, UE 310 sends the stored information to secondary base station 330 after transitioning to an active state and completing the RACH procedure. In yet another implementation, the UE sends information about CQI measurements to primary base station 320 for subsequent forwarding to secondary base station 330. As discussed, in another implementation, only the most recent CQI metric based on the parameters described above is sent to secondary base station 330. In another implementation, where the set of CQI measurements is based on reference signals transmitted by the set of cells 335-1 to 335-N of the SCG, the UE 310 transmits the set of CQI measurements to the secondary base station 330.

[0103] In some implementations, UE 310 sends information to secondary base station 330 in response to receiving a signal from primary base station 320 for operation in active state. In another implementation, when UE 310 is operating in active state, UE 310 monitors the PDCCH channel for data transmitted by secondary base station 330. In yet another implementation, UE 310 receives data from secondary base station 330 via PDSCH in active state.

[0104] Method 500 may further include: the secondary base station 330 performing link adaptation to transmit data to the UE 310 based on one or more CQI measurements (block 512). In some implementations, the secondary base station 330 performs link adaptation by selecting a modulation and coding scheme (MCS) based on one or more CQI measurements. Method 500 also includes: the secondary base station 330 transmitting data to the UE 310 based on link adaptation (block 514).

[0105] Figure 6 Showing the use of Figure 3 An example flowchart of another method for power-efficient link adaptation operation of a cellular communication system is provided. Method 600 is described with reference to the previously described cellular communication device 300. In this example, the primary base station 320 and the secondary base station 330 may be in a dual-connectivity configuration with the UE 310.

[0106] The method 600 includes the UE 310 performing one or more CQI measurements based on one or more reference signals received from the secondary base station 330 (block 602). In some implementations, the UE operates in a dormant state while performing the operations specified in block 602. In some implementations, each CQI measurement can be based on a SINR measurement. In another implementation, if the secondary base station 330 includes a set of cells 335-1 through 335-N in an SCG, then: the UE 310 performs a set of CQI measurements based on a set of reference signals received from the set of cells 335-1 through 335-N, respectively.

[0107] The method 600 also includes the UE 310 transmitting information about the one or more CQI measurements to the primary base station 320 (block 604). In some implementations, the UE 310 is in a dormant state associated with an SCG of the secondary base station 330. In another implementation, the UE 310 transmits the information via a signaling radio bearer (SRB). In another implementation, the UE 310 transmits the information via SRB1 as defined by LTE or NR specifications. In yet another implementation, the UE 310 transmits the information via a PUCCH channel. In still another implementation, the UE 310 transmits the information via a PUSCH channel. In another implementation, if the UE 310 receives a set of reference signals from a set of cells 335-1 through 335-N of the SCG, then the UE 310 transmits information about the set of CQI measurements to the primary base station 320.

[0108] The method 600 also includes the primary base station 320 receiving the information about the one or more CQI measurements from the UE 310 (block 606). Again, in different implementations, the primary base station 320 can receive the information about the one or more CQI measurements via a SRB, SRB1, PUCCH, or PUSCH. In yet another implementation, the primary base station 320 can receive a set of CQI measurements associated with a set of cells 335-1 through 335-N of an SCG of the secondary base station 330.

[0109] The method 600 also includes the primary base station 320 transmitting the information about the one or more CQI measurements to the secondary base station 330 (block 608). In some implementations, the primary base station 320 transmits the information to the secondary base station 330 via a control link or backhaul communication link (e.g., signaling link 322 (e.g., an Xn / X2 type link)). In another implementation, the primary base station 320 transmits a set of CQI measurements associated with a set of cells 335-1 through 335-N in an SCG to the secondary base station 330.

[0110] The method 600 can also include the secondary base station 330 performing link adaptation to transmit data to the UE 310 based on the one or more CQI measurements (block 610). In some implementations, the secondary base station 330 performs link adaptation by selecting a modulation coding scheme (MCS) based on the one or more CQI measurements. The method 600 also includes the secondary base station 330 transmitting data to the UE 310 based on the link adaptation (block 612).

[0111] Figure 7 A block diagram illustrating an example hardware implementation for a base station 700 is shown. The base station 700 is depicted employing a processing system 714. For example, the base station 700 can correspond to any of the base stations previously discussed herein, such as the primary base station 320 and the secondary base station 330.

[0112] The base station 700 can be implemented with a processing system 714 that includes one or more processors 704. Examples of processors 704 include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the base station device 700 can be configured to perform any one or more of the functions described herein. That is, the processor 704, as utilized in a base station 700, can be used to implement any one or more of the processes and procedures described below.

[0113] In this example, the processing system 714 can be implemented with a bus architecture, represented generally by the bus 702. The bus 702 can include any number of interconnecting buses and bridges depending on the specific application of the processing system 714 and the overall design constraints. The bus 702 links together various circuits such as the processor(s) (represented by the processor 704), memory 705, and computer-readable media (represented by the computer-readable medium 706). The bus 702 can also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits.

[0114] The bus interface 708 provides an interface between the bus 702 and the wireless transceiver 710 and the backhaul link interface 711. The wireless transceiver 710 allows the base station 700 to communicate with various other apparatus over a transmission medium (e.g., an air interface). The backhaul link interface 711 allows the base station 700 to communicate with various other apparatus over a backhaul communication link (e.g., a wired interface). Depending upon the nature of the apparatus, a user interface 712 (e.g., keypad, display, touch screen, speaker, microphone, control buttons, etc.) can also be provided. Of course, such a user interface 712 is optional, and can be omitted in some examples.

[0115] The processor 704 is responsible for managing the bus 702 and general processing, including the execution of software stored on the computer-readable medium 706. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software, when executed by the processor 704, causes the processing system 714 to perform the various functions described infra for any particular apparatus. The computer-readable medium 706 and the memory 705 can also be used for storing data used by the processor 704 in executing software.

[0116] The computer-readable medium 706 can be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, for example, magnetic storage devices (e.g., hard disk; floppy disk); optical disk devices (e.g., compact disk (CD), digital versatile disk (DVD)); smart cards; flash memory devices (e.g., card, stick, or key drive); random access memories (RAMs); read only memories (ROMs); programmable ROMs (PROMs); erasable PROMs (EPROMs); electrically erasable PROMs (EEPROMs); registers; removable disk; and any other suitable medium for storing software or instructions that can be accessed and read by a computer. The computer-readable medium 706 can exist on the processing system 714, outside of the processing system 714, or distributed across multiple entities including the processing system 714. The computer-readable medium 706 can be embodied in a computer program product. By way of example, a computer program product can include a computer-readable medium in packaging material. In some examples, the computer-readable medium 706 can be part of the memory 705. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

[0117] In some aspects of the disclosure, the processor 704 can include circuitry configured for various functions. For example, the processor 704 can include resource assignment and scheduling circuitry 742 configured to assign and schedule resources for signaling radio bearers (SRBs) and data radio bearers (DRBs) with a UE. The resource assignment and scheduling circuitry 742 can also be configured to execute resource assignment and scheduling software 752 stored in the computer-readable medium 706 to implement one or more of the functions described herein.

[0118] The processor 704 also includes DL traffic and control generation and transmission circuitry 744 for transmitting DL signaling and data to UEs. For example, with respect to the wireless communication system 300, the DL traffic and control generation and transmission circuitry 744 of the base station 320 or 330 will control the transmission of DL signaling and data to the UE 310 via one or more SRBs 312 or 316 and one or more DRBs 314 or 318. The DL traffic and control channel and transmission circuitry 744 can also be configured to execute the DL traffic and control channel reception and processing software 754 stored in the computer-readable medium 706 to implement one or more of the functions described herein.

[0119] The processor 704 can also include uplink (UL) traffic and control channel reception and processing circuitry 746 configured to receive and process uplink control channels and uplink traffic channels from one or more UEs. For example, the UL traffic and control channel reception and processing circuitry 746 can be configured to receive uplink control information (UCI) or uplink user data traffic from one or more UEs via one or more SRBs 312 or 316 and one or more DRBs 314 or 318. The UL traffic and control channel reception and processing circuitry 746 can also be configured to execute the UL traffic and control channel reception and processing software 756 stored in the computer-readable medium 706 to implement one or more of the functions described herein.

[0120] The processor 704 can also include backhaul signaling management circuitry 748 configured to perform backhaul signaling management 748 for the base station. For example, the backhaul signaling management circuitry 748 can be configured to transmit information to the secondary base station 330 via the backhaul communication link 322 regarding one or more CQI measurements for the primary base station 320. The backhaul signaling management circuitry 748 can also be configured to execute the backhaul signaling management software 758 stored in the computer-readable memory to implement one or more of the functions described herein.

[0121] Figure 8 An example flowchart illustrating a method 800 for reporting, by a primary base station, information to a secondary base station regarding channel quality indicator (CQI) measurements performed by a user equipment (UE) based on reference signals received from the secondary base station for link adaptation purposes is shown. The method 800 includes the processor 704 receiving, via the wireless transceiver 710, information associated with one or more channel quality indicator (CQI) measurements related to a second base station from a user equipment (UE) (block 802). The method 800 also includes the processor 704 transmitting, via the backhaul link interface 711, the information to the second base station (block 804).

[0122] Figure 9A block diagram illustrating an example hardware implementation for a user equipment (UE) 900. The UE 900 is depicted employing a processing system 914. The UE 900 can correspond to any of the UEs previously discussed herein, such as the UE 310, for example.

[0123] The UE 900 can be implemented with a processing system 914 that includes one or more processors 904. Examples of processors 904 include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the UE 900 can be configured to perform any one or more of the functions described herein. That is, the processor 904, as utilized in a UE 900, can be used to implement any one or more of the processes and procedures described below.

[0124] In this example, the processing system 914 can be implemented with a bus architecture, represented generally by the bus 902. The bus 902 can include any number of interconnecting buses and bridges, depending on the specific application of the processing system 914 and the overall design constraints. The bus 902 links together various circuits such as the processor(s) (represented by the processor(s) 904), the memory 905, and the computer-readable media (represented by the computer-readable media 906). The bus 902 can also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

[0125] The bus interface 908 provides an interface between the bus 902 and the wireless transceiver 910. The wireless transceiver 910 allows the UE 900 to communicate with various other apparatus over a transmission medium (for example, an air interface). Depending upon the nature of the apparatus, a user interface 912 (for example, a keypad, display, touch screen, speaker, microphone, control buttons, etc.) can also be provided. Of course, such a user interface 912 is optional, and can be omitted in some examples.

[0126] The processor 904 is responsible for managing the bus 902 and general processing, including the execution of software stored on the computer-readable medium 906. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software, when executed by the processor 904, causes the processing system 914 to perform the various functions described infra for any particular apparatus. The computer-readable medium 906 and the memory 905 can also be used for storing data that is manipulated by the processor 904 when executing software.

[0127] The computer-readable medium 906 can be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, for example, magnetic storage devices (e.g., hard disk; floppy disk); optical disk devices (e.g., compact disk (CD), digital versatile disk (DVD)); smart cards; flash memory devices (e.g., card, stick, or key drive); random access memories (RAMs); read only memories (ROMs); programmable ROMs (PROMs); erasable PROMs (EPROMs); electrically erasable PROMs (EEPROMs); registers; removable disk; and any other suitable medium for storing software or instructions that can be accessed and read by a computer. The computer-readable medium 906 can exist in the processing system 914, outside of the processing system 914, or distributed across multiple entities including the processing system 914. The computer-readable medium 906 can be embodied in a computer program product. By way of example, a computer program product can include a computer-readable medium in packaging material. In some examples, the computer-readable medium 906 can be part of the memory 905. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

[0128] In some aspects of the disclosure, the processor 904 can include circuitry configured for various functions. For example, the processor 904 can include resource assignment and scheduling circuitry 942 configured to assign and schedule resources for signaling radio bearers (SRBs) and data radio bearers (DRBs) with a base station. The resource assignment and scheduling circuitry 942 can also be configured to execute resource assignment and scheduling software 952 stored in the computer-readable medium 906 to implement one or more of the functions described herein.

[0129] The processor 904 also includes DL traffic and control generation and transmission circuitry 944 for receiving DL signaling and data from a base station. For example, with respect to the wireless communication system 300, the DL traffic and control generation and transmission circuitry 944 of the UE 310 controls reception of DL signaling and data from the primary base station 320 via one or more SRBs 312 or 316 and controls reception of DL signaling and data from the secondary base station 330 via one or more DRBs 314 or 318. The DL traffic and control channel and transmission circuitry 944 can also be configured to execute DL traffic and control channel reception and processing software 954 stored in the computer-readable medium 906 to implement one or more of the functions described herein.

[0130] The processor 904 can also include uplink (UL) traffic and control channel reception and processing circuitry 946 configured to process and send uplink control channel signaling and uplink traffic data to one or more base stations. For example, the UL traffic and control channel reception and processing circuitry 946 can be configured to send uplink control information (UCI) or uplink user data traffic to the primary base station 320 via one or more SRBs 312 or 316 and to send uplink control information (UCI) or uplink user data traffic to the secondary base station 330 via one or more DRBs 314 or 318. The UL traffic and control channel reception and processing circuitry 946 can also be configured to execute UL traffic and control channel reception and processing software 956 stored in the computer-readable medium 906 to implement one or more of the functions described herein.

[0131] Figure 10 An example flowchart of a method 1000 of reporting, by a user equipment (UE), radio resource management (RRM) measurements performed by the UE based on reference signals received from a secondary base station to a primary base station is shown. The method 1000 includes the processor 904 receiving one or more reference signals from a first base station via the wireless transceiver 910 (block 1002). The method 1000 also includes the processor 904 performing one or more radio resource management (RRM) measurements based on the one or more reference signals (block 1004). The method 1000 also includes the processor 904 sending information about the one or more RRM measurements to a second base station via the wireless transceiver 910 (block 1006).

[0132] Figure 11An example flow diagram of a method 1100 of reporting, by a user equipment (UE), radio resource management (RRM) measurements performed by the UE based on reference signals received from a secondary base station to a primary base station is shown. The method 1100 includes the processor 904 receiving one or more reference signals from a first base station via the wireless transceiver 910 (block 1102). The method 1100 also includes the processor 904 performing one or more channel quality indicator (CQI) measurements based on the one or more reference signals (block 1104). The method 1100 also includes the processor 904 storing information regarding the one or more CQI measurements in the memory 905 (block 1106). The method 1100 also includes the processor 904 transmitting the stored information regarding the one or more CQI measurements to the first base station or a second base station via the wireless transceiver 910 (block 1108).

[0133] Several aspects of a wireless communication network have been presented with reference to the example implementations. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure can be extended to other telecommunication systems, network architectures and communication standards.

[0134] By way of example, various aspects can be implemented within other systems defined by 3GPP, such as Long-Term Evolution (LTE), Evolved Packet System (EPS), the Universal Mobile Telecommunication System (UMTS), or the Global System for Mobile (GSM). Various aspects can also be implemented within systems defined by the 3rd Generation Partnership Project 2 (3GPP2), such as CDMA2000 or Ultra Mobile Broadband (UMB). For example, various aspects can be implemented within systems employing IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wide Band (UWB), Bluetooth, or other suitable systems. The actual telecommunication standard, network architecture, or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

[0135] As used herein, a phrase referring to "at least one of a list of items means any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c.

[0136] The various illustrative logics, logical blocks, modules, circuits and algorithm processes described in connection with the implementations disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware or software depends on the particular application and design constraints imposed on the overall system.

[0137] The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein can be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor can be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor also can be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes or methods can be performed by an electrical circuit comprising discrete elements, such as resistors, capacitors, inductors, transistors, logic gates, look-up tables, or any other such components.

[0138] In one or more aspects, the functions described can be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.

[0139] If implemented in software, the functions can be stored or transmitted over as one or more instructions or code on a computer-readable medium. Process steps of the methods disclosed herein can be implemented in a processing circuitry that can reside in a computer program product that can comprise one or more computer-readable media. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm can reside in one or any combination of the aforementioned computer-readable media, which can be located in a computing device or computing system that can be personal computer, server, handheld device, etc. Accordingly, the claims should not be limited to the above implementation, but should be given the broadest reasonable interpretation available.

[0140] Various modifications to these implementations will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with the principles and novel features disclosed in this disclosure, including the generic principles, preferred embodiments and novel features disclosed in this disclosure and their

[0141] Further, those of skill in the art will recognize that the terms "on" and "under" are sometimes used to describe the orientation of one element relative to another in the drawings, and indicate relative positioning on a properly oriented page relative to the orientation of the drawing, and can not reflect the proper orientation of any device as implemented.

[0142] Certain features described in this specification in the context of separate implementations can also be implemented, separately or in any suitable combination, in combination with each other. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features can be described above as acting in particular combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

[0143] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring such an order, nor that all illustrated operations be performed, to implement the desired results. Further, the drawings can illustrate example processes in a flow diagram form. However, the example processes can be embodied in any convenient or desirable machine-readable medium having stored instructions of the example processes. The machine-readable medium can be a machine-readable storage medium or a machine-readable communication medium. The instructions can be executed by one or more processors of a processing platform or a computing platform. The instructions can be software written in any suitable programming language or any suitable combination of programming languages. The instructions can be written in machine code, assembly language, or a high-level programming language such as C, C++, Java, Python, or any other suitable programming language. The instructions can be compiled or interpreted. The instructions can be stored in any suitable location, including one or more memory devices included in the processing platform or computing platform or accessible by the processing platform or computing platform. The instructions can be stored in the memory of the processing platform or computing platform during use, execution, or deployment.

Claims

1. A method for wireless communication at an apparatus of a user equipment (UE), comprising: receiving one or more reference signals from a first base station; performing one or more channel quality indicator (CQI) measurements based on the one or more reference signals; storing information regarding the one or more CQI measurements; and transmitting the stored information regarding the one or more CQI measurements to the first base station or a second base station. performing the one or more CQI measurements is based on a configuration for the one or more CQI measurements received from the first base station.

2. The method of claim 1, wherein, transmitting the stored information includes transmitting the stored information to the first base station in response to receiving a signal from the second base station for operating in an active state associated with a secondary cell group (SCG) with the first base station.

3. The method of claim 1, wherein, monitoring a physical downlink control channel (PDCCH) for data transmitted by the first base station to the UE in the active state.

4. The method of claim 3, further comprising: receiving data via a physical downlink shared channel (PDSCH) in the active state.

5. The method of claim 3, further comprising: the second base station is a master base station in a multi-RAT dual connectivity configuration and the first base station is a secondary base station in the multi-RAT dual connectivity configuration.

6. The method of claim 1, wherein, performing a random access channel (RACH) procedure with the first base station.

7. The method of claim 1, further comprising: transmitting the stored information includes transmitting the stored information after transitioning to the active state associated with the SCG with the first base station and the RACH procedure is complete.

8. The method of claim 7, wherein, transmitting the stored information is based on a parameter.

9. The method of claim 1, wherein, the parameter specifies a number of one or more most recent CQI measurements to be included in the information transmitted to the first base station.

10. The method of claim 9, wherein, the parameter specifies one or more most recent CQI measurements within a defined time interval to be included in the information transmitted to the first base station.

11. The method of claim 9, wherein, the UE is in a dormant or deactivated operating state associated with a secondary cell group (SCG) with the first base station during receiving the one or more reference signals, performing the one or more CQI measurements, and storing the information regarding the one or more CQI measurements.

12. The method of claim 1, wherein, no data transmissions occur between the UE and the first base station when the UE is in the dormant or deactivated operating state.

13. The method of claim 12, wherein, the UE does not monitor for physical downlink control channel (PDCCH) signals transmitted by the first base station when the UE is in the dormant or deactivated operating state.

14. The method of claim 12, wherein, the first base station includes a set of cells, wherein receiving the one or more reference signals includes receiving a set of reference signals from the set of cells, respectively, wherein performing the one or more CQI measurements includes performing a set of CQI measurements based on the set of reference signals based on a configuration for the set of CQI measurements received from the first base station, and wherein transmitting the stored information includes transmitting information regarding the set of CQI measurements to the first base station.

15. The method of claim 1, wherein, 16. A user equipment, comprising: a memory; a wireless transceiver; and a processor configured to: receive one or more reference signals from a first base station via the wireless transceiver; ​ ​ performing one or more channel quality indicator (CQI) measurements based on the one or more reference signals; storing information about the one or more CQI measurements in the memory; and sending the stored information to the first base station or the second base station via the wireless transceiver.

17. The user equipment of claim 16, wherein, the processor is configured to perform the one or more CQI measurements based on a configuration for the one or more CQI measurements received from the first base station.

18. The user equipment of claim 16, wherein, the processor is configured to send stored information to the first base station in response to receiving a signal from the second base station via the wireless transceiver to operate in an active state associated with a secondary cell group (SCG) with the first base station.

19. The user equipment of claim 18, wherein, the processor is configured to monitor a physical downlink control channel (PDCCH) for data transmitted by the first base station in the active state.

20. The user equipment of claim 18, wherein, the processor is configured to receive data via a physical downlink shared channel (PDSCH) via the wireless transceiver in the active state.

21. The user equipment of claim 16, wherein, the processor is configured to perform a random access channel (RACH) procedure with the first base station.

22. The user equipment of claim 21, wherein, the processor is configured to send the stored information after transitioning to the active state associated with the secondary cell group (SCG) with the first base station and the RACH procedure is complete.

23. The user equipment of claim 16, wherein, the processor is configured to send the stored information based on a parameter.

24. The user equipment of claim 23, wherein, the parameter specifies a number of one or more most recent CQI measurements to be included in the information sent to the first base station.

25. The user equipment of claim 23, wherein, the parameter specifies one or more most recent CQI measurements within a defined time interval to be included in the information sent to the first base station.

26. The user equipment of claim 16, wherein, the processor operates in an operating state during the receiving the one or more reference signals, performing the one or more CQI measurements, and storing the information about the one or more CQI measurements.

27. The user equipment of claim 26, wherein, the processor is configured to not receive data from the first base station while in the operating state.

28. The user equipment of claim 26, wherein, the processor is configured to not monitor a physical downlink control channel (PDCCH) signal transmitted by the first base station while in the operating state.

29. An apparatus for wireless communication, comprising means for performing a method of any of claims 1-15.

30. A non-transitory computer-readable medium storing computer-executable code, comprising code for causing a processor in a user equipment to perform a method of any of claims 1-15.

31. A wireless communication system, comprising: a first base station; a second base station; and a user equipment configured to perform a method of any of claims 1-15.

32. A method for wireless communication at an apparatus of a first base station, comprising: receiving, from a user equipment (UE), information associated with one or more channel quality indicator (CQI) measurements related to a second base station; and sending the information to the second base station. the receiving the information occurs when the UE is in a dormant state. ​ 33. The method of claim 32, wherein, ​ 34. The method of claim 32, wherein, transmitting the information to the second base station occurs via a backhaul communication link.

35. The method of claim 32, wherein, transmitting the information to the second base station occurs via an Xn / X2 link as defined in LTE or NR specifications.

36. The method of claim 32, wherein, receiving the information from the UE occurs via a signaling radio bearer (SRB).

37. The method of claim 32, wherein, receiving the information from the UE occurs via a signaling radio bearer 1 (SRB1) as defined in LTE or NR.

38. The method of claim 32, wherein, receiving the information from the UE includes receiving the information via a physical uplink control channel (PUCCH).

39. The method of claim 32, wherein, receiving the information from the UE includes receiving the information via a physical uplink shared channel (PUSCH).

40. The method of claim 32, wherein, the first base station is a master base station in a multi-RAT dual connectivity configuration and the second base station is a secondary base station.

41. The method of claim 32, wherein, the information of the one or more channel quality indicator (CQI) measurements includes a set of CQI measurements related to a set of cells supported by the second base station, respectively.

42. A base station comprising: a wireless transceiver; a backhaul interface; and a processor configured to: receive, via the wireless transceiver, information associated with one or more channel quality indicator (CQI) measurements related to another base station from a user equipment (UE); and transmit, via the backhaul interface, the information to the second base station.

43. The base station of claim 42, wherein, the processor is configured to receive the information from the user equipment via a signaling radio bearer (SRB).

44. The base station of claim 42, wherein, the processor is configured to receive the information from the user equipment via a signaling radio bearer 1 (SRB1) as defined in LTE or NR.

45. The base station of claim 42, wherein, the processor is configured to receive the information from the user equipment via a physical uplink control channel (PUCCH).

46. The base station of claim 42, wherein, the processor is configured to receive the information from the UE via a physical uplink shared channel (PUSCH).

47. An apparatus for wireless communication comprising means for performing a method of any of claims 32-41.

48. A non-transitory computer-readable medium storing computer-executable code including code for causing a processor in a base station to perform a method of any of claims 32-41.

49. A wireless communication system comprising: a user equipment; a first base station; a second base station configured to perform a method of any of claims 32-41.

Images