Method and apparatus for saving network energy by turning off a transmission chain

Abstract

The method includes transmitting to the UE a first set of one or more probing messages, the first set of one or more probing messages including a set of reference signals. The method includes receiving from a group of UEs a first CSI report including first channel state information (CSI) derived from measurements of the set of reference signals in response to the first one or more probing messages. The method includes transmitting to the UE a second set of one or more probing messages, the second set of one or more probing messages including a subset of the reference signals. The method further includes receiving a second CSI report including a second CSI derived from measurements of the subset of reference signals in response to the second set of one or more probing messages.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority based on U.S. Patent Application No. 63 / 396,457, filed on August 9, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] This disclosure generally relates to communication systems, and more particularly, to methods and apparatuses for saving network energy by turning off transmission chains.

Background Art

[0003] In conventional multiple - input multiple - output (MIMO) systems, multiple ports (e.g., channel state information reference signal (CSI - RS) ports) or data streams may be mapped to multiple transmit radio distribution units (TXRUs). This operation may be referred to as port virtualization and may be regarded as digital precoding. Then, the output of the TXRU can be mapped to an antenna unit via TXRU virtualization in the analog domain. The output of the TXRU can be mapped to a group of co - polarized antenna elements via an analog phase shifter or a variable - gain amplifier. The terms transmission chain and TXRU may be used interchangeably. A TXRU can include a power amplifier, a filter, a digital / analog converter, etc. Since these components consume most of the power within the gNB, turning off the TXRU can be used to save energy within the network.

[0004] Turning off the transmission chain of the transmission antenna or antenna elements may be implemented by the gNB or network implementation. When the transmission chain is turned off, the transmission energy from the base station decreases. However, since turning off the transmission chain is executed without cooperation with the UE, energy saving is limited or the impact on UE performance becomes significant. In particular, due to the lack of cooperation with the UE, it becomes impossible to guarantee that the UE group that will be most affected due to the received power loss can maintain acceptable communication performance. In addition, since the base station components cannot be dynamically turned on / off (connected / disconnected), it results in energy saving that is not optimal for performance loss.

[0005] Improvements are presented in this specification. These improvements may also be applicable to other multi-access technologies and telecommunication standards using these technologies.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The following presents a simplified overview of such embodiments in order to provide a basic understanding of one or more embodiments of the present disclosure. This overview is not an extensive overview of all possible embodiments, nor is it intended to identify the main or important elements of all embodiments or to delineate the scope of any or all embodiments. Its sole purpose is to present in a simplified form some concepts of one or more embodiments of the present disclosure as a prelude to the more detailed description presented later.

[0007] A method, apparatus, and non-transitory computer-readable medium for saving network energy by turning off a transmission chain are disclosed by the present disclosure.

Means for Solving the Problems

[0008] According to an exemplary embodiment, a method performed by at least one processor of a base station includes, in a first state, transmitting to a UE a first set of one or more sounding messages, where the first set of one or more sounding messages includes a set of reference signals. The method further includes receiving, in response to the first one or more sounding messages, a first CSI report from a group of UEs, the first CSI report including first channel state information (CSI) derived from measurements of the set of reference signals. The method further includes, in a second state, transmitting to the UE a second set of one or more sounding messages, where the second set of one or more sounding messages includes a subset of reference signals. The method further includes receiving, in response to the second set of one or more sounding messages, a second CSI report including second CSI derived from measurements of the subset of reference signals.

[0009] According to an exemplary embodiment, the apparatus comprises at least one memory configured to store computer program code, and at least one processor configured to access the at least one memory and operate as instructed by the computer program code. The computer program code includes first transmission code configured to cause at least one of the at least one processor to transmit, in a first state, a first set of one or more sounding messages to a UE, where the first set of one or more sounding messages includes a set of reference signals. The computer program code includes first reception code configured to cause at least one of the at least one processor to receive, in response to the first one or more sounding messages, a first CSI report from a group of UEs including first channel state information (CSI) derived from measurements of the set of reference signals. The computer program code includes second transmission code configured to cause at least one of the at least one processor to transmit, in a second state, a second set of one or more sounding messages to the UE, where the second set of one or more sounding messages includes a subset of reference signals. The computer program code includes the step of second receiving a second CSI report including second CSI derived from measurements of the subset of reference signals in response to the second set of one or more sounding messages.

[0010] According to an exemplary embodiment, a non-transitory computer-readable medium storing instructions that, when executed by a processor in a base station, cause the processor to execute a method, the method including, in a first state, transmitting a first set of one or more sounding messages to a UE, where the first set of one or more sounding messages includes a set of reference signals. The method includes receiving, in response to the first one or more sounding messages, a first channel state information (CSI) report from a group of UEs, where the first CSI report includes a first CSI derived from measurements of the set of reference signals. The method further includes, in a second state, transmitting a second set of one or more sounding messages to the UE, where the second set of one or more sounding messages includes a subset of the reference signals. The method further includes receiving, in response to the second set of one or more sounding messages, a second CSI report including a second CSI derived from measurements of the subset of the reference signals.

[0011] Further embodiments are described in the following description, some of which will be apparent from the description and / or may be learned by practice of the presented embodiments of the disclosure.

[0012] The above and other aspects, features, and aspects of the embodiments of the disclosure will become apparent from the following description in conjunction with the accompanying drawings.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0020] The following detailed description of the exemplary embodiments refers to the accompanying drawings. The same reference numerals in different drawings may identify the same or similar elements.

[0021] The foregoing disclosure provides examples and explanations, but is not intended to be comprehensive or to limit the disclosed implementation forms to the exact form. Changes and modifications are possible in light of the above disclosure, or changes and modifications may be obtained from the implementation of the implementation forms. Furthermore, one or more features or components of one embodiment may be incorporated into another embodiment (or one or more features of another embodiment), or may be combined with another embodiment (or one or more features of another embodiment). In addition, in the flowcharts and descriptions of operations provided below, it is understood that one or more operations may be omitted, one or more operations may be added, one or more operations may be (at least partially) executed simultaneously, and the order of one or more operations may be interchanged.

[0022] It will be apparent that the systems and / or methods described herein may be implemented in various forms of hardware, firmware, or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods is not limiting of the implementation form. Thus, the operation and behavior of the systems and / or methods are described herein without reference to specific software code, and it is understood that the software and hardware can be designed to implement the systems and / or methods based on the description herein.

[0023] Even if a particular combination of features is recited in the claims and / or disclosed herein, these combinations are not intended to limit the disclosure of possible implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed herein. Each of the dependent claims listed below may depend directly on only one claim, but the disclosure of possible implementations includes each dependent claim in combination with all the other claims in the claim set.

[0024] Elements, acts, or instructions used in this specification should not be construed as important or essential unless explicitly described as such. Also, as used in this specification, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." When only one item is intended, the term "one" or a similar expression is used. Also, as used in this specification, terms such as "has," "have," "having," "include," "including," etc. are intended to be non-limiting terms. Further, the phrase "based on" is intended to mean "at least partially based on" unless otherwise specified. Further, expressions such as "at least one of [A] and [B]" or "at least one of [A] or [B]" should be understood to include only A, only B, or both A and B.

[0025] Throughout this specification, references to "one embodiment," "an embodiment," or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the solution. Thus, the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, refer to the same embodiment.

[0026] Furthermore, the described features, advantages, and characteristics of the present disclosure may be combined in any suitable manner in one or more embodiments. One of ordinary skill in the art will recognize that, in light of the description herein, the present disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in particular embodiments that are not present in all embodiments of the present disclosure.

[0027] Embodiments of the present disclosure relate to performing network energy saving by turning off a transmission chain. In some embodiments, a gNB can enter one of various energy saving states at a given time (e.g., a normal state and an energy saving state in which a plurality of transmission chains are turned off), and can dynamically indicate the current and future states to a group of UEs. In some embodiments, the gNB collects feedback from a group of UEs, and based on the feedback, classifies the group of UEs into at least two groups, namely (1) a group of UEs that can maintain acceptable performance when some of the transmission chains are turned off, and (2) a group of UEs that cannot maintain acceptable performance when some of the transmission chains are turned off. The group of UEs within the second group can be configured using coverage extension techniques. The gNB can dynamically turn on / off a plurality of transmission chains. When the gNB is in an energy saving state, the group of UEs within the second group can interrupt specific communication activities.

[0028] FIG. 1 is a diagram of an exemplary device for implementing embodiments of the present disclosure. Device 100 may correspond to any type of known computer, server, or data processing device. For example, device 100 may include a processor, a personal computer (PC), a printed circuit board (PCB) with a computing device, a minicomputer, a mainframe computer, a microcomputer, a telephone computing device, a wired / wireless computing device (e.g., a smartphone, a personal digital assistant (PDA)), a laptop, a tablet, a smart device, or any other device with similar functionality.

[0029] In some embodiments, as shown in FIG. 1, device 100 can include a set of components such as processor 120, memory 130, storage component 140, input component 150, output component 160, and communication interface 170.

[0030] Bus 110 can comprise one or more components that enable communication between the set of components of device 100. For example, bus 110 can be a communication bus, a crossover bar, a network, or the like. Although bus 110 is shown as a single line in FIG. 1, bus 110 can be implemented using multiple (two or more) connections between the set of components of device 100. The present disclosure is not limited in this regard.

[0031] Device 100 may include one or more processors such as processor 120. Processor 120 may be implemented in hardware, firmware, and / or a combination of hardware and software. For example, processor 120 may include a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), an Accelerated Processing Unit (APU), a microprocessor, a microcontroller, a Digital Signal Processor (DSP), a Field-Programmable Gate Array (FPGA), an Application-Specific Integrated Circuit (ASIC), a general-purpose single-chip or multi-chip processor, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. Processor 120 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration. In some embodiments, certain processes and methods may be performed by circuitry specific to a given function.

[0032] Processor 120 can control the overall operation of device 100 and / or a set of components of device 100 (e.g., memory 130, storage component 140, input component 150, output component 160, communication interface 170).

[0033] Device 100 may further include a memory 130. In some embodiments, the memory 130 can include a random access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a magnetic memory, an optical memory, and / or another type of dynamic or static storage device. The memory 130 can store information and / or instructions for use (e.g., execution) by the processor 120.

[0034] The storage component 140 of the device 100 can store information and / or computer-readable instructions and / or code related to the operation and use of the device 100. For example, the storage component 140, together with a corresponding drive, can include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optical disk, and / or a solid-state disk), a compact disc (CD), a digital versatile disc (DVD), a universal serial bus (USB) flash drive, a personal computer memory card international association (PCMCIA) card, a floppy disk, a cartridge, a magnetic tape, and / or another type of non-transitory computer-readable medium.

[0035] Device 100 may further include an input component 150. The input component 150 can include one or more components that enable the device 100 to receive information via user input, etc. (e.g., a touch screen, a keyboard, a keypad, a mouse, a stylus, a button, a switch, a microphone, a camera, etc.). Alternatively or additionally, the input component 150 can include sensors for sensing information (e.g., a global positioning system (GPS) component, an accelerometer, a gyroscope, an actuator, etc.).

[0036] The output component 160 of the device 100 may include one or more components (e.g., a display, a liquid crystal display (LCD), light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), a haptic feedback device, a speaker, etc.) that can provide output information from the device 100.

[0037] Device 100 may further include a communication interface 170. The communication interface 170 may include a receiver component, a transmitter component, and / or a transceiver component. The communication interface 170 may enable Device 100 to establish a connection with another device (e.g., a server, another device) and / or transfer communications. The communication may be performed via a wired connection, a wireless connection, or a combination of a wired connection and a wireless connection. The communication interface 170 may enable Device 100 to receive information from another device and / or provide information to another device. In some embodiments, the communication interface 170 may provide communication with another device via a network such as a Local Area Network (LAN), a Wide Area Network (WAN), a Metropolitan Area Network (MAN), a private network, an ad hoc network, an intranet, the Internet, an optical fiber-based network, a cellular network (e.g., a Fifth Generation (5G) network, a Long-Term Evolution (LTE) network, a Third Generation (3G) network, a Code Division Multiple Access (CDMA) network, etc.), a Public Land Mobile Network (PLMN), a telephone network (e.g., a Public Switched Telephone Network (PSTN)), etc., and / or a combination of these types or other types of networks. Alternatively or additionally, the communication interface 170 may provide communication with another device via a device-to-device (D2D) communication link such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi, LTE, 5G, etc.In other embodiments, communication interface 170 may include an Ethernet interface, an optical interface, a coaxial interface, an infrared interface, a radio frequency (RF) interface, and the like.

[0038] Device 100 may execute one or more processes described herein. Device 100 may perform operations based on the execution by processor 120 of computer-readable instructions and / or code that may be stored by a non-transitory computer-readable medium such as memory 130 and / or storage component 140. The computer-readable medium may refer to a non-transitory memory device. The memory device may include memory space within a single physical memory device and / or memory space distributed across multiple physical memory devices.

[0039] The computer-readable instructions and / or code may be read into memory 130 and / or storage component 140 from another computer-readable medium or from another device via communication interface 170. The computer-readable instructions and / or code stored in memory 130 and / or storage component 140, when executed or upon execution by processor 120, may cause device 100 to execute one or more processes described herein.

[0040] Alternatively or additionally, hardwired circuitry may be used, instead of or in combination with software instructions, to execute one or more processes described herein. Accordingly, the embodiments described herein are not limited to any particular combination of hardware circuitry and software.

[0041] The number and arrangement of components shown in FIG. 1 are provided as an example. In practice, there may be additional components, fewer components, different components, or components in a different arrangement compared to the components shown in FIG. 1. Further, two or more components shown in FIG. 1 may be implemented within a single component, or a single component shown in FIG. 1 may be implemented as a plurality of distributed components. Alternatively or additionally, a set of (one or more) components shown in FIG. 1 can perform one or more functions described as being performed by another set of components shown in FIG. 1.

[0042] FIG. 2 is a diagram showing an example of a wireless communication system according to various embodiments of the present disclosure. The wireless communication system 200 (which can also be referred to as a wireless wide area network (WWAN)) can include one or more user equipment (UE) 210, one or more base stations 220, at least one transmission network 230, and at least one core network 240. The device 100 (FIG. 1) may be incorporated into the UE 210 or the base station 220.

[0043] One or more UEs 210 may access at least one core network 240 and / or IP services 250 via a connection to one or more base stations 220 through the RAN domain 224 and through at least one transport network 230. Examples of UEs 210 may include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems (GPS), multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electric meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similarly functioning devices. Some of the one or more UEs 210 may be referred to as Internet-of-Things (IoT) devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). The one or more UEs 210 may also be referred to as stations, mobile stations, subscriber stations, mobile units, subscriber units, radio units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless terminals, remote terminals, handsets, user agents, mobile agents, clients, or some other suitable terms.

[0044] One or more base stations 220 may communicate wirelessly with one or more UEs 210 through the RAN domain 224. Each base station of the one or more base stations 220 can provide communication coverage to one or more UEs 210 located within the geographical coverage area of that base station 220. In some embodiments, as shown in FIG. 2, the base station 220 can transmit one or more beamformed signals to one or more UEs 210 in one or more transmission directions. One or more UEs 210 can receive the beamformed signals from the base station 220 in one or more reception directions. Alternatively or additionally, one or more UEs 210 may transmit beamformed signals to the base station 220 in one or more transmission directions. The base station 220 can receive beamformed signals from one or more UEs 210 in one or more reception directions.

[0045] One or more base stations 220 may include macro cells (e.g., high-power cellular base stations) and / or small cells (e.g., low-power cellular base stations). Small cells may include femto cells, pico cells, and micro cells. The base station 220, whether a macro cell or a large cell, may include an access point (AP), an evolved (or evolved universal terrestrial radio access network (E-UTRAN)) Node B (eNB), a next-generation Node B (gNB), or any other type of base station known to those skilled in the art and / or may be referred to as such.

[0046] One or more base stations 220 may be configured to interface with (e.g., establish a connection with, transfer data to, etc.) at least one core network 240 through at least one transmission network 230. In addition to other functions, one or more base stations 220 may perform one or more of the following functions: namely, transfer of data (e.g., uplink data) received from one or more UEs 210 to at least one core network 240 via at least one transmission network 230, and transfer of data (e.g., downlink data) received from at least one core network 240 to one or more UEs 210 via at least one transmission network 230.

[0047] The transmission network 230 may transfer data (e.g., uplink data, downlink data) and / or signaling between the RAN domain 224 and the CN domain 244. For example, the transmission network 230 may provide one or more backhaul links between one or more base stations 220 and at least one core network 240. The backhaul link may be wired or wireless.

[0048] The core network 240 may be configured to provide one or more services (e.g., enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine Type Communications (mMTC), etc.) to one or more UEs 210 connected to the RAN domain 224 via the TN domain 234. Alternatively or additionally, the core network 240 may function as an entry point for the IP services 250. The IP services 250 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), streaming services (e.g., video, audio, games, etc.), and / or other IP services.

[0049] In some embodiments, the gNB (e.g., 220) can deactivate (e.g., turn off (disconnect), not use) a subset of the transmit-receive chains, for example, to save energy. Depending on the mapping from ports to TXRUs, this deactivation can deactivate one or more ports (e.g., CSI-RS ports). The deactivated resources may not be available to that group of UEs. The state where the TXRU is turned off may be referred to as an energy-saving state. The state where the TXRU is not turned off may be referred to as a normal state.

[0050] The TXRU may not be visible to the UE group (for example, the UE group may not know the exact number of TXRUs used by the gNB). However, deactivating multiple TXRUs may render multiple ports unavailable to the UE. In some embodiments, the gNB can configure its UE group in at least two distinct configurations. The first configuration may include a first set of ports (e.g., CSI-RS ports), and the second configuration may include a second set of ports. The second set may include a smaller number of antenna ports than the first set. The second configuration may be used when the TXRU chain is deactivated. For example, if there is a one-to-one mapping between CSI-RS ports and TXRUs and there are K (e.g., K = 32) TXRUs, K CSI-RS ports can be supported. For example, if K / 2 TXRUs are deactivated, K / 2 CSI-RS ports can be supported. In other examples, when the TXRU is deactivated, the number of supported ports does not change, but the total transmit power and / or beamwidth may also decrease as the number of active TXRUs decreases. The received signal energy may also decrease.

[0051] Embodiments of the present disclosure are disclosed assuming that the gNB and / or network can be in two states (a normal state and an energy-saving state). However, the embodiments may be extended to three or more states. For example, multiple energy-saving states may exist depending on how much energy can be saved in each state. As an example, with K TXRUs, two separate energy-saving states can respectively correspond to the cases where K / 4 and K / 2 TXRUs are turned off. The energy-saving state can be achieved by turning off multiple TXRUs, but the same embodiments may be applicable if the energy-saving state is enabled by other mechanisms (e.g., turning off antenna elements).

[0052] In some embodiments, the energy saving procedure may include probing the UE group, classifying the UEs, configuring (setting) the UEs, instructing the energy saving state, and applying the energy saving. When probing the UE group, the gNB may instruct the UE group to feedback the channel state information (CSI) derived for the normal state and / or the energy saving state. The UE group may also be instructed to report quantities other than the CSI. The state during which the gNB probes the UE group may sometimes be called the probing phase. In the classification of UEs, the UE group may be classified into separate groups based on the feedback of the UEs. For example, based on the communication ability of the UE group with a reduced number of TXRUs. As an example, a UE group that may require expansion (e.g., coverage expansion) when some TXRUs are turned off can be classified into the first group. A UE group that can continue to operate without expansion can be classified into the second group.

[0053] In the configuration of the UE, the gNB can form a group of UEs within the first group using coverage extension or other extension techniques. These techniques can be used when the gNB is in an energy-saving state. For example, these groups of UEs can be configured to monitor the Physical Downlink Control Channel (PDCCH) only when the gNB is in the normal state and not to monitor the PDCCH when the gNB is in the energy-saving state. In another example, these groups of UEs can be configured to apply specific coverage extension techniques when the gNB is in the energy-saving state. During the energy-saving state indication, the gNB can adapt the behavior of the energy-saving state over time. For example, the gNB may be in the normal state in some slots (e.g., all TXRUs are on), and the gNB may be in the energy-saving state in some slots (e.g., some TXRUs are off). The progression of the gNB's state over time can be called an energy-saving pattern, and the current and / or future state of the gNB may be indicated to the group of UEs based on the energy-saving pattern. After the energy state is indicated, the gNB can apply energy saving (e.g., turn off the TXRUs based on the indicated energy-saving pattern). The state of the gNB while applying energy saving can be called the energy-saving phase. The probing phase and the energy-saving phase may partially or completely overlap in time.

[0054] In some embodiments, the gNB may transmit a reference signal and / or other signals that can be used by the UE to measure and derive CSI (e.g., CSI-RS, synchronization signal block (SSB)). The UE can derive at least two types of CSI (type 1 and type 2). Type 1 may correspond to the reference signal transmitted by the gNB when the gNB is in the normal state. Type 2 may correspond to the reference signal transmitted by the gNB when the gNB is in the energy-saving state. For example, the gNB can have 32 TXRUs and 32 CSI-RS ports. The first type of CSI can be derived by the UE using this configuration. At a specific interval, the gNB can turn off 16 of the TXRUs and use the remaining active TXRUs to transmit the reference signal. In this specific interval, the number of CSI-RS ports can be set to 16. The second type of CSI can be derived using this configuration.

[0055] In some embodiments, the UE may be configured using two CSI reporting configurations. The parameters in one configuration (e.g., the number of CSI-RS ports, the number of CSI-RS resources, etc.) may correspond to the normal state, and the other configuration parameters may correspond to the energy-saving state. The types of CSI configurations may be periodic, aperiodic, and quasi-static.

[0056] When the base station is not in an energy-saving state (for example, when it is in a normal state), the UE may be configured to measure and report legacy CSI. For example, in the normal state, the base station can transmit with 64 antennas. In some embodiments, the UE may be instructed to skip CSI-RS measurements in a specific time window. During that time window, the UE may be instructed to measure CSI-RS and report CSI corresponding to the energy-saving state. For example, for a given interval / window, the gNB instructs the UE that 8 antennas are used instead of 64. This window can be referred to as a time skip window. An exemplary time series 300 with a time skip window 302 is shown in FIG. 3. During the time skip window, the base station may be in an energy-saving state and the UE does not use the original configuration of 64 antennas. Accordingly, the UE skips measuring 64 CSI-RS and reporting the corresponding CSI. Instead, during the time skip window / interval, the UE may measure only 8 antennas and report CSI for the 8 antennas. As illustrated in the time series 400 having a time window 402 (FIG. 4), the UE may measure another set of CSI-RS associated with the energy-saving state and report the associated CSI. CSI reporting may be performed outside the window and DL transmission may be only inside the window.

[0057] In some embodiments, the skip window may be configured by the gNB. The window may be periodic and can be configured by the periodicity of the start point (or end point) of the window, an offset value for shifting the start point (or end point), and the time length (e.g., in slot units or milliseconds). In another way, the CSI report for every k-th configuration can be configured to be associated with the energy-saving state. The UE can be instructed about the reference signal to be used to derive the CSI report for every k-th. For example, it can be assumed that the last CSI-RS and / or the last SSB before the time point of the k-th CSI report are transmitted with some TXRUs turned off. In another example, a window can be defined with respect to the time point of the k-th CSI report, and it can be assumed that the reference signals within this window are transmitted with TXRUs turned off.

[0058] In another example, the UE may be configured with the CSI report configuration corresponding to the normal state. The specific parameter values within the configuration can be updated temporarily. For example, the number of CSI-RS ports may be 32 in the normal state. During the time window 302 shown in FIG. 3, the number of ports may be temporarily set to 16. Similarly, the number of ports may be set to 16 to derive the k-th CSI report.

[0059] In some embodiments, the CSI report for the energy-saving state may be activated by an aperiodic indication as shown in FIG. 5 showing an exemplary time series 500. The UE can be configured with a type 2 CSI configuration, which can be activated using the PDCCH. After the active time has ended, the activated type 2 CSI configuration can be deactivated. The activation of the type 2 CSI report configuration can deactivate the type 1 CSI report configuration, which means that the UE can skip (e.g., interrupt) the type 1 CSI report configuration until the end of the active time.

[0060] In some embodiments, the PDCCH can set / reset the values of certain parameters of the CSI configuration. In this regard, after the expiration of the valid time, the values of these parameters can be set to the values before the PDCCH instruction. For example, the MAC CE can instruct the UE on the CSI-RS parameters shown in Table 1. The bits and / or code points within the PDCCH can set the number of CSI-RS ports in the configuration to one of the values in the table by indicating the row index. The values of other parameters can be added to the table as columns. [Table 1]

[0061] The probing phase and the energy saving phase may partially or fully overlap, and the embodiments disclosed above may be used in the energy saving phase.

[0062] During the probing phase (e.g., when turning off some TXRUs), specific UE procedures can be skipped and / or interrupted. For example, one or more of the following are applicable:

[0063] The UE does not monitor the PDCCH.

[0064] The UE interrupts the evaluation of the radio link quality.

[0065] The UE interrupts the transmission of an indication to the upper layer (e.g., the MAC layer) that the radio link quality is worse than a threshold.

[0066] The UE interrupts the transmission of the physical random access channel (PRACH).

[0067] The UE interrupts the transmission of a scheduling request (SR).

[0068] The UE MAC layer interrupts the increment of the beam failure indication (BFI) counter and / or the start of the beam failure detection timer.

[0069] The parameter beamFailureInstanceMaxCount is set to a larger value, for example, infinity. And,

[0070] When the UE evaluates the link quality, the UE can use the thresholds (Q out,LR +Q out_offset ) and / or (Q in,LR +Q in_offset ). The offset value can be configured by the gNB and can be applicable only during the probing phase (e.g., within the probing time window). Similarly, an offset value may be added to the parameters Q in and Q out .

[0071] In addition to CSI, the UE can feedback one or more additional following quantities:

[0072] Power headroom (tolerance) for beam failure events. For example, reference signal received power (RSRP) - Q out,LR and / or RSRP - Q in_LR .

[0073] Power headroom (tolerance) for radio link failure events. For example, RSRP - Q out and / or RSRP - Q in . And

[0074] RSRP / SINR measured in the probing phase - RSRP / SINR measured before the probing phase (e.g., the final value of RSRP / SINR before the probing phase).

[0075] In some embodiments, the collected feedback can be used to classify UE groups based at least on whether the UE groups can continue normal operation when the gNB is in an energy-saving state. For example, a first group of UE groups is in the cell center and can maintain acceptable performance by turning off a certain number of TXRUs. A second group of UE groups is on the edge of the cell and can maintain acceptable performance when a certain number of TXRUs are turned off and an extension, such as a coverage extension, is applied. A third group of UE groups may not be able to maintain acceptable performance even if an extension is applied when a certain number of TXRUs are turned off. Different classifications may be applicable at different levels of the energy-saving state.

[0076]

[0077] In some embodiments, when the gNB enters an energy-saving state, the behavior of the UE groups can be determined by which group they belong to. A group ID can be assigned to the UE. Based on the group ID, the UE can adjust its behavior when the gNB is in an energy-saving state. For example, if the UE is in group 3, it can transition to the sleep mode when the gNB is in an energy-saving state. In another example, the gNB can send a go-to-sleep signal before entering the energy-saving state and instructing one or more UE groups to transition to the sleep state. The go-to-sleep signal can be monitored by UE groups belonging to a specific group and / or can be configured by specific tags / parameters. The go-to-sleep signal can be PDCCH-based, and 1 bit in the PDCCH can indicate whether to transition to sleep for a set of UE groups.

[0078] In some embodiments, the UE can be instructed and / or configured to apply coverage extension techniques when the gNB is in an energy-saving state. For example, one or more Physical Downlink Control Channels (PDCCHs), Physical Downlink Shared Channels (PDSCHs), Physical Uplink Shared Channels (PUSCHs), and Physical Uplink Control Channels (PUCCHs) may be subject to repetition according to the energy-saving state of the gNB. Activation / deactivation of the coverage extension technique can be determined by the energy-saving state of the gNB.

[0079] In some embodiments, the gNB may be in various energy-saving states according to a specific time. For example, in a specific slot, the gNB may be in a normal state, but in some slots, the gNB may be in an energy-saving state. The gNB can send an indication of the energy-saving state to a group of UEs. For example, a UE-common PDCCH can be used for the indication. The group of UEs can be configured using a search space for monitoring the PDCCH. One or more bits in the Downlink Control Information (DCI) can indicate the energy-saving state over a certain period of time. For example, when the time duration is N slots, the bit sequence

[11001] can indicate that the gNB is in a power-saving state (bit 1) during the 1st, 2nd, and 5th periods of the N slots, and the gNB is in a normal state (bit 0) during the 3rd and 4th periods of the N slots. By allocating more bits per time duration, more than three states can be indicated. In another example, the UE can monitor the PDCCH based on a search space. The DCI in the PDCCH can indicate the energy-saving state(s) and the corresponding duration(s).

[0080] Embodiments that indicate a probing phase can be used to indicate an energy-saving state. For example, the energy-saving phase may occur periodically, and a window similar to a "probing window" can also be defined by the gNB as the time interval during which it is in the energy-saving phase. As another example, similar to the definition of the DRX ON period, specific slots can be represented as belonging to the normal state (e.g., in these slots, the TXRU is not turned off), and the remaining slots can be represented as being in the energy-saving state. In some embodiments, the energy-saving state may be activated by non-periodic signaling using PDCCH and / or MAC CE, as disclosed for the probing phase.

[0081] Figure 6 shows a flowchart of an embodiment of a process 600 for implementing network energy savings. Process 600 may be executed by a gNB. Process 600 can start with an operation S602 in which the gNB transmits one or more probing messages to one or more UE groups. The probing message can include a reference signal such as a CSI reference signal.

[0082] The process proceeds to operation S604, where the gNB receives one or more CSI reports in response to one or more sounding messages. The process proceeds to operation S606, where each UE is classified into one of a plurality of classification groups based on the one or more CSI reports. For example, the classification groups may include groups 1 to 3 described above. The process proceeds to operation S608, where a UE group is configured based on the classification. For example, the UE group may be configured for a type 1 or type 2 reference signal as described above. The process proceeds to operation S610, where the gNB transmits an energy saving state indication to the UE group based on the classification. For example, the gNB can transmit a bit pattern (e.g., 1101) indicating in which slots the gNB will enter the energy saving state. The process proceeds to operation S612, where the gNB applies an energy saving mode by turning off one or more transmit chains based on the energy saving state indication.

[0083] FIG. 7 shows a flowchart of an embodiment of a process 700 for sounding a UE group. The process 700 can start with an operation S702 where a base station transmits one or more sounding messages to a UE in a first state. For example, the base station may be in a normal state where each antenna of the base station is on. The first set of one or more sounding messages can include a set of reference signals (e.g., 64 beams). The process proceeds to operation S704, where the base station receives a first CSI report in response to the one or more first sounding messages. For example, the first CSI report can provide a first CSI corresponding to measurements of a set of reference signals (e.g., 64 beams).

[0084] The process proceeds to operation S706, where the base station transmits a second set of one or more sounding messages to the UE in a second state. As an example, the second state may be an energy-saving state where the base station turns off one or more antennas. The second set of one or more sounding messages can include a subset of reference signals (e.g., 8 beams). An indication may be provided to the UE indicating when the base station enters the energy-saving state. The process proceeds to operation S708, where the base station receives a second CSI report in response to the second set of one or more sounding messages. The second CSI report can include a second CSI based on measurements of a subset of reference signals (e.g., 8 beams). Thus, the second CSI report can provide CSI corresponding to the energy-saving state of the network.

[0085] The above disclosure provides examples and explanations, but is not intended to be exhaustive or to limit to the exact form of the disclosed implementation. Modifications and variations are possible in light of the above disclosure, or the modifications and variations can be obtained from the practice of the implementation.

[0086] It is understood that the specific order or hierarchy of blocks in the processes / flowcharts disclosed herein is illustrative. It is understood that the specific order or hierarchy of blocks in a process / flowchart can be reconfigured based on design preferences. Additionally, some blocks may be combined, omitted, etc. The appended method claims present various block elements in a sample order and are not meant to be limited to the presented specific order or hierarchy.

[0087] Some embodiments may relate to systems, methods, and / or computer-readable media at any possible technical detail level of integration. Further, one or more of the above-described components may be implemented as instructions stored on a computer-readable medium and executable by at least one processor (and / or may include at least one processor). The computer-readable medium may include one or more computer-readable non-transitory storage media having computer-readable program instructions for causing a processor to perform operations.

[0088] A computer-readable storage medium can be a tangible device that can hold and store instructions for use by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanically encoded device such as a punch card or raised structure in a groove having instructions recorded thereon, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium should not be construed as being a transitory signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission media (e.g., an optical pulse passing through an optical fiber cable), or an electrical signal transmitted through a wire.

[0089] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to respective computing / processing devices or to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface within each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions for storage on a computer-readable storage medium within each respective computing / processing device.

[0090] The computer-readable program code / instructions for performing the operations may be in any combination of one or more programming languages, including assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuits, or source code or object code written in an object-oriented programming language such as Smalltalk and C++, and a procedural programming language such as the "C" programming language or a similar programming language. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, for example, an electronic circuit including a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA) may execute the computer-readable program instructions by utilizing the state information of the computer-readable program instructions for personalizing the electronic circuit to perform the aspects or operations.

[0091] These computer-readable program instructions, when executed via the processor of a computer or other programmable data processing apparatus, create means for causing the functions / acts specified in one or more blocks of the flowchart and / or block diagram to be implemented, and may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to generate a machine for implementing the functions / acts so specified. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and / or other devices to function in a particular manner, such that the computer-readable storage medium storing the instructions comprises a manufacture including instructions for implementing the aspects of the functions / acts specified in one or more blocks of the flowchart and / or block diagram.

[0092] The computer-readable program instructions may also be loaded onto a computer, other programmable apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to generate a computer-implemented process, such that the instructions executed on the computer, other programmable apparatus, or other device implement the functions / acts specified in one or more blocks of the flowchart and / or block diagram.

[0093] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer-readable media according to various embodiments. In this regard, each block in the flowchart or block diagram can represent a module, segment, or portion of one or more executable instructions for implementing a particular logical function. The methods, computer systems, and computer-readable media can include additional blocks, fewer blocks, different blocks, or differently arranged blocks compared to those shown in the figures. In some alternative implementations, the functions described in the blocks may be performed in a different order than those described in the figures. For example, two blocks shown in succession may actually be performed simultaneously, or substantially simultaneously, or the blocks may sometimes be performed in the reverse order depending on the related functions. It should also be noted that each block of the block diagrams and / or flowchart diagrams, and combinations of blocks of the block diagrams and / or flowchart diagrams, can be implemented by a dedicated hardware-based system that performs the specified function or operation, or a combination of dedicated hardware and computer instructions.

[0094] It will be apparent that the systems and / or methods described herein may be implemented in various forms of hardware, firmware, or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods is not limiting of the implementation. Thus, the operation and behavior of the systems and / or methods are described herein without reference to a particular software code, and it is understood that software and hardware can be designed based on the description herein to implement the systems and / or methods.

[0095] The above disclosure also encompasses the embodiments listed below. (1) A method executed by at least one processor of a base station, the method comprising, in a first state, transmitting to a UE a first set of one or more probing messages, wherein the first set of the one or more probing messages includes a set of reference signals, and in response to the first one or more probing messages, receiving from the UE group a first channel state information (CSI) report, wherein the first CSI report includes a first CSI derived from measurements of the set of reference signals; in a second state, transmitting to the UE a second set of one or more probing messages, wherein the second set of the one or more probing messages includes a subset of the reference signals, and in response to the second set of the one or more probing messages, receiving a second CSI report including a second CSI derived from measurements of the subset of the reference signals. (2) The method according to feature (1), wherein the first state is a normal state and the second state is an energy-saving state. (3) The method according to feature (2), wherein in the energy-saving state, the base station turns off one or more antennas. (4) The method according to any one of features (1) to (3), wherein the first set of the one or more probing messages includes an indication of a window having a duration for which the UE measures a subset of the reference signals. (5) The method according to feature (4), wherein the base station constructs the window at periodic time intervals. (6) The method according to feature (4) or (5), wherein the second CSI report is transmitted from the UE to the base station at a timing outside the window. (7) The method according to any one of features (2) to (6), further comprising transmitting to the UE a predetermined downlink signal for ending measurement of the set of reference signals in the normal energy state and starting measurement of the subset of the reference signals in the energy-saving state. (8) The method according to feature (7), wherein the predetermined downlink signal is a Physical Downlink Control Channel (PDCCH) signal. (9) The method according to feature (7) or (8), wherein the measurement of the subset of the reference signals ends after a predetermined time interval. (10) The method according to any one of features (1) to (9), further comprising the step of classifying each UE of the one or more UE groups into one of a plurality of classification groups based on the one or more CSI reports. (11) The method according to feature (10), wherein the plurality of classification groups include (i) a first classification group: where, when the base station is in the energy saving state, each UE assigned to the first classification group does not utilize cell extension coverage, and (ii) a second classification group: where, when the base station is in the energy saving state, each UE assigned to the second classification group utilizes cell extension coverage. (12) The method according to feature (11), wherein the cell extension coverage includes repetition of one or more downlink signals or repetition of one or more uplink signals. (13) The method according to feature (12), wherein the one or more downlink signals include one of a Physical Downlink Control Channel (PDCCH) signal and a Physical Downlink Shared Channel (PDSCH) signal, and the one or more uplink signals include one of a Physical Uplink Shared Channel (PUSCH) signal and a Physical Uplink Control Channel (PUCCH) signal. (14) The method according to any one of features (2) to (13), further comprising the step of transmitting to the UE an indication of the energy saving state including one or more bits designating one or more time slots to which the energy saving state is applied. An apparatus comprising at least one memory configured to store computer program code, and at least one processor configured to access the at least one memory and operate as instructed by the computer program code, wherein the computer program code comprises: a first transmission code configured to cause at least one of the at least one processor to transmit, in a first state, a first set of one or more sounding messages to a UE, wherein the first set of the one or more sounding messages includes a set of reference signals; a first reception code configured to cause at least one of the at least one processor to receive, in response to the first one or more sounding messages, a first channel state information (CSI) report from the UE group, wherein the first CSI report includes a first CSI derived from measurements of the set of reference signals; a second transmission code configured to cause at least one of the at least one processor to transmit, in a second state, a second set of one or more sounding messages to the UE, wherein the second set of the one or more sounding messages includes a subset of the reference signals; and a step of second receiving, in response to the second set of the one or more sounding messages, a second CSI report including a second CSI derived from measurements of the subset of the reference signals. (16) The apparatus according to feature (15), wherein the first state is a normal state and the second state is an energy saving state. (17) The apparatus according to feature (16), wherein in the energy saving state, the base station turns off one or more antennas. (18) The apparatus according to any one of features (15) to (17), wherein the first set of the one or more sounding messages includes an indication of a window having a duration during which the UE measures a subset of the reference signals. (19) The apparatus according to feature (18), wherein the base station configures the window at periodic time intervals. A non-transitory computer-readable medium storing instructions that, when executed by a processor in a base station, cause the processor to execute a method, the method comprising: in a first state, transmitting a first set of one or more probing messages to a UE, wherein the first set of one or more probing messages includes a set of reference signals; receiving, in response to the first one or more probing messages, a first channel state information (CSI) report from the UE group, wherein the first CSI report includes a first CSI derived from measurements of the set of reference signals; in a second state, transmitting a second set of one or more probing messages to the UE, wherein the second set of one or more probing messages includes a subset of the reference signals; and receiving, in response to the second set of one or more probing messages, a second CSI report including a second CSI derived from measurements of the subset of the reference signals.

Claims

1. A method performed by at least one processor of a base station, the method comprising: in a first state, transmitting to a UE a first set of one or more sounding messages, wherein the first set of the one or more sounding messages includes a set of reference signals; receiving, from the group of UEs, a first channel state information (CSI) report in response to the first one or more sounding messages, wherein the first CSI report includes first CSI derived from measurements of the set of reference signals; in a second state, transmitting to the UE a second set of one or more sounding messages, wherein the second set of the one or more sounding messages includes a subset of the reference signals; receiving a second CSI report including second CSI derived from measurements of the subset of the reference signals in response to the second set of the one or more sounding messages.

2. The method according to claim 1, wherein the first state is a normal state and the second state is an energy saving state.

3. The method according to claim 2, wherein in the energy saving state, the base station turns off one or more antennas.

4. The method according to claim 1, wherein the first set of the one or more sounding messages includes an indication of a window having a duration for which the UE measures a subset of the reference signals.

5. The method according to claim 4, wherein the base station configures the window at periodic time intervals.

6. The method according to claim 4, wherein the second CSI report is transmitted from the UE to the base station at a timing outside the window.

7. transmitting to the UE a predetermined downlink signal for ending measurement of the set of reference signals in the normal energy state and starting measurement of the subset of the reference signals in the energy saving state; The method according to claim 2, further comprising.

8. The method according to claim 7, wherein the predetermined downlink signal is a physical downlink control channel (PDCCH) signal.

9. The method according to claim 7, wherein measurement of the subset of the reference signals ends after a predetermined time interval.

10. The method according to claim 1, further comprising the step of classifying each UE of the one or more UE groups into one of a plurality of classification groups based on the one or more CSI reports.

11. The method according to claim 10, wherein the plurality of classification groups include: (i) a first classification group: where, when the base station is in the energy-saving state, each UE assigned to the first classification group does not utilize cell extension coverage; and (ii) a second classification group: where, when the base station is in the energy-saving state, each UE assigned to the second classification group utilizes cell extension coverage.

12. The method according to claim 11, wherein the cell extension coverage includes repetition of one or more downlink signals or repetition of one or more uplink signals.

13. The method according to claim 12, wherein the one or more downlink signals include one of a physical downlink control channel (PDCCH) signal and a physical downlink shared channel (PDSCH) signal, and the one or more uplink signals include one of a physical uplink shared channel (PUSCH) signal and a physical uplink control channel (PUCCH) signal.

14. The step of transmitting to the UE an indication of the energy-saving state including one or more bits specifying one or more time slots to which the energy-saving state is applied. The method according to claim 2, further comprising the step of:

15. An apparatus comprising at least one memory configured to store computer program code, and at least one processor configured to access the at least one memory and operate as commanded by the computer program code, wherein the computer program code includes a first transmission code configured to cause at least one of the at least one processor to transmit a first set of one or more probing messages to a UE in a first state, wherein the first set of the one or more probing messages includes a set of reference signals. At least one of the at least one processor is configured to receive, in response to the first one or more probing messages, a first channel state information (CSI) report from the UE group, where the first CSI report includes first CSI derived from measurements of the set of reference signals. At least one of the at least one processor is configured to transmit, in a second state, a second set of one or more probing messages to the UE, where the second set of the one or more probing messages includes a subset of the reference signals. receiving, second, a second CSI report including second CSI derived from measurements of the subset of the reference signals, in response to the second set of the one or more probing messages. An apparatus comprising. [

16. ] The apparatus according to claim 15, wherein the first state is a normal state and the second state is an energy saving state. [

17. ] The apparatus according to claim 16, wherein in the energy saving state, the base station turns off one or more antennas. [

18. ] The apparatus according to claim 15, wherein the first set of the one or more probing messages includes an indication of a window having a duration for which the UE measures a subset of the reference signals. [

19. ] The apparatus according to claim 18, wherein the base station constructs the window at periodic time intervals. [

20. ] A non-transitory computer-readable medium storing instructions that, when executed by a processor in a base station, cause the processor to perform a method, the method comprising: transmitting, in a first state, a first set of one or more probing messages to a UE, where the first set of the one or more probing messages includes a set of reference signals. receiving, in response to the first one or more probing messages, a first channel state information (CSI) report from the UE group, where the first CSI report includes first CSI derived from measurements of the set of reference signals. transmitting, in a second state, a second set of one or more probing messages to the UE, where the second set of the one or more probing messages includes a subset of the reference signals. receiving, in response to the second set of the one or more probing messages, a second CSI report including a second CSI derived from measurements of the subset of the reference signals, in a non-transitory computer-readable medium.

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