WO2025150505A1 - Control device, wireless access network node, wireless terminal, and methods thereof - Google Patents

Abstract

This control device selectively applies any of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network (RAN) node. The plurality of downlink DTX patterns are different from each other in terms of the numbers of subframes in which downlink transmission by the RAN node is stopped in a radio frame. This enables the RAN node to use, for example, one selected from a plurality of downlink DTX patterns in which the numbers of subframes in which downlink transmission by the RAN node is stopped in the radio frame are different from each other.

Description

CONTROL DEVICE, RADIO ACCESS NETWORK NODE, RADIO TERMINAL, AND METHODS THEREOF

The present disclosure relates to a control device, a radio access network node, a wireless terminal, and methods thereof.

Non-Patent Document 1 discloses potential solutions for energy saving in Evolved Universal Terrestrial Radio Access Network (E-UTRAN), i.e. Long Term Evolution (LTE) networks. Section 7 of Non-Patent Document 1 describes several solutions for intra-eNB energy saving. One of these solutions is to configure Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) subframes within the scope supported according to the current specification limitations. The term "MBSFN" may be an abbreviation for Multicast-broadcast single-frequency network (MBSFN). Configuring MBSFN subframes as much as possible allows for reducing the eNB transmission time, since MBSFN subframes have fewer Cell-specific Reference Signals (CRS) than normal subframes. Current 3rd Generation Partnership Project (3GPP®) specifications allow up to five MBSFN subframes in a radio frame in Time Division Duplex (TDD) LTE systems and up to six MBSFN subframes in Frequency Division Duplex (FDD) LTE systems. Utilizing currently available MBSFN subframes is an efficient way for energy-efficient network operation in LTE, potentially achieving energy savings of the order of 30-50% in typical traffic scenarios compared to operation without MBSFN subframes. This solution can already be supported without any impact on current 3GPP specifications.

Non-Patent Document 2 discusses the possibility of introducing enhanced cell discontinuous transmission (DTX). Non-Patent Document 2 points out that the main contributor to downlink transmission time in LTE normal subframes is the CRS transmitted in every subframe. Non-Patent Document 2, like Non-Patent Document 1, mentions that the use of MBSFN subframes can reduce the eNB's transmission-time fraction. However, Non-Patent Document 2 states that the potential benefits of using MBSFN subframes are limited by the fact that even in MBSFN subframes, the CRS needs to be transmitted in at least one Orthogonal Frequency Division Multiplex (OFDM) symbol per subframe. To address this issue, Non-Patent Document 2 proposes using the SSS instead of the CRS for UE mobility measurements used for cell search, thereby reducing the number of CRSs in empty cells with no active terminals (i.e., User Equipments (UEs)). Non-Patent Documents 3-5 provide further discussion of CRS reduction and the use of SSS measurements instead of CRS measurements, as proposed in Non-Patent Document 2.

Currently, 3GPP is discussing network energy saving for 3GPP Release 18 (see, for example, non-patent document 6). Network energy saving is abbreviated as NES. As described in non-patent document 6, there are various techniques to improve network energy saving, which include cell DTX and discontinuous reception (DRX). In one example, the network may provide a mechanism to inform UEs in a cell whether the cell is in an inactive state. During cell DTX or cell DRX, i.e. while the cell is in an inactive state, the cell may not transmit or receive, or may only maintain limited transmission or reception.

For example, as described in section 6.1 of 3GPP TS 2.0, when cell DTX is activated, a 5G NR cell does not need to transmit some periodic signals and channels, such as cell common channels and signals and UE specific signals and channels. These periodic signals and channels include, for example, Synchronization Signal (SS)/Physical Broadcast Channel (PBCH) block (SSB), System Information (SI), paging, and the cell common Physical Downlink Control Channel (PDCCH). The transmission patterns of these periodic signals and channels can be semi-statically or dynamically adapted. Adaptation of the transmission pattern includes changing the periodicity, changing the location of time resources, and omitting certain signals or channels. In one example transmission pattern, the repetition period of SSB and System Information Block Type 1 (SIB1) is extended to 40 ms, and only the Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) are transmitted during the remaining 20 ms opportunities.

The Open Radio Access Network (O-RAN) Alliance is conducting technical studies on architectures including Non-Real-Time (Non-RT) RAN Intelligent Controller (RIC) and Near-RT RIC and is providing technical specifications for these. The O-RAN Working Group 1 (WG1) is defining the overall O-RAN architecture and use cases. These use cases include the energy saving (ES) use case (see, for example, Section 4.21 of Non-Patent Document 7 and Non-Patent Document 8). The ES use case includes three sub-use cases: carrier and cell switch off/on, radio frequency (RF) channel switch off/on, and Advanced Sleep Mode.

In the carrier and cell switch off/on sub-use case, both the controlling system and the controlled system have non-real time time scales. The Non-RT RIC provides carrier and cell switch off/on parameter settings to E2 nodes (e.g., O-eNB, O-Central Unit (CU), O-Distributed Unit (DU)) using the O1 interface. The Non-RT RIC also provides carrier and cell switch off/on parameter settings to the O-Radio Unit (RU) via the Open Fronthaul Management plane (M-plane). A Non-RT RIC application (rApp) hosted on the Non-RT RIC may be used to host a trained Machine Learning (ML) model and achieve an optimized ES configuration, such as switching time, that can provide the optimal desired trade-off between ES and user Quality of Service (QoS).

For the RF channel switch off/on sub-use case, there is a first non-real-time implementation and a second near-real-time implementation. In the first non-real-time implementation, the Non-RT RIC configures user QoS to E2 nodes (e.g., O-eNB, O-CU, O-DU) using the O1 interface and provides massive multiple-input multiple-output (MIMO) system reconfiguration to the O-RU via the M-plane of Open Fronthaul. In the second near-real-time implementation, the Non-RT RIC provides the trained ML model to the Near-RT RIC via the A1 interface. The Near-RT RIC application (xApp) hosted on the Near-RT RIC optimizes RF channel configurations by performing inference using the trained ML model and provides the optimized RF channel configurations to E2 nodes (e.g., O-eNB, O-CU, O-DU) via the E2 interface. The E2 node performs massive MIMO system reconfiguration to the O-RU via the Open Fronthaul M-plane.

Advanced Sleep Modes (ASMs) are used to reduce energy consumption (EC) by automatically switching off part of the O-RU components every symbol (ASM1), slot (ASM2) or frame (ASM3). The objective of this sub-use case is to maximize the duration of ASMs (and corresponding ES) during which O-RU components are switched off, taking into account user QoS constraints on latency. For this purpose, ASM activation policies can be set (e.g. order and number of ASMs at each level) and system configurations can be applied (e.g. setting SSB periodicity; compressing data transmission in certain slots and leaving the remaining slots "put to sleep" free; reducing transmission of synchronization signals, reducing random access and paging opportunities, etc.). The Near-RT RIC requests the ML model over the A1 interface. Once this ML model is deployed and activated, the Near-RT RIC optimizes the ES by setting the ASM policies and system configurations over the E2 interface and the Open Fronthaul M-plane. The xApp in the Near-RT RIC uses the trained ML model to infer ASM activation policies and system configurations and provides them to the E2 nodes (e.g., O-eNB, O-CU, O-DU) via the E2 interface. The E2 nodes send the ASM and system parameters to the O-RU via the Open Fronthaul M-plane.

Patent Document 1 discloses that a base station monitors the remaining charge of a battery that supplies power to the base station, and if the actual battery charge is less than the planned battery charge, sets control parameters that are more effective at saving power according to the insufficient battery charge. The control parameters may set the suspension of transmission and reception functions during time periods when no bandwidth is allocated in the uplink and downlink. Alternatively, the control parameters may cause suspension of transmission and reception operations for an entire frame if even scheduling information regarding bandwidth allocation is not transmitted. There are various methods and control parameters for achieving sleep control or suspension of transmission and reception operations depending on the target wireless standard.

JP 2012-253621 A

3GPP TR 36.927 V17.0.0 (2022-04), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Ev olved Universal Terrestrial Radio Access (E-UTRA); Potential solutions for energy saving for E-UTRAN (Release 17)", April 2022 Ericsson, ST-Ericsson, "Extended cell DTX for enhanced energy-efficient network operation", R1-095011, 3GPP TSG-RAN WG1 #59, Jeju, Korea, November 9-13, 2009 Samsung, “Considerations on Extended Cell DTX”, R1-100144, 3GPP TSG RAN WG1 #59bis, Valencia, Spain, January 18-22, 2010 Ericsson, ST-Ericsson, "Enabling Enhanced Cell DTX in LTE", R1-101309, 3GPP TSG-RAN WG1 #60, San Francisco, USA, February 22-26, 2010 Ericsson, ST-Ericsson, "UE impact of Cell DTX in LTE", R1-101552, 3GPP TSG-RAN WG1 #60, San Francisco, USA, February 22-26, 2010 3GPP TR 38.864 V18.1.0 (2023-03) "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on network energy savings for NR (Release 18)", March 2023 O-RAN ALLIANCE Working Group 1, "O-RAN Use Cases Analysis Report 12.0", O-RAN.WG1.Use-Cases-Analysis-Report-R003-v12.00, October 2023 O-RAN ALLIANCE Working Group 1, "O-RAN Network Energy Saving Use Cases Technical Report 2.0", O-RAN.WG1.Network-Energy-Savings-Technical-Report-R003-v02.00, June 2023

Non-Patent Documents 2-5 teach cell DTX techniques that involve stopping downlink transmissions, including CRS transmissions, in MBSFN subframes in a radio frame. However, these documents do not explicitly disclose using multiple downlink DTX patterns with different numbers of subframes in which transmission is stopped in a radio frame. Other documents cited in the Background section also do not explicitly disclose this. Depending on some conditions, for example but not limited to the state of power supply to a base station (e.g., eNB), it may be useful to selectively use multiple downlink DTX patterns with different numbers of subframes in which transmission is stopped in a radio frame. Therefore, alternative or improved methods to enable this may be needed.

One of the objectives that the embodiments disclosed in this specification aim to achieve is to provide an apparatus, a method, and a program that contribute to solving at least one of the problems, including the problems described above. It should be noted that this objective is only one of the objectives that the embodiments disclosed in this specification aim to achieve. Other objectives or objectives and novel features will become apparent from the description of this specification or the accompanying drawings.

In a first aspect, the control device is configured to selectively apply one of a plurality of downlink DTX patterns to the radio access network node. The plurality of downlink DTX patterns differ from one another in the number of subframes during which downlink transmission by the radio access network node is suspended within a radio frame.

In a second aspect, the method performed by the control device includes selectively applying one of a plurality of downlink DTX patterns to a radio access network node. The plurality of downlink DTX patterns differ from one another in the number of subframes during which downlink transmission by the radio access network node is suspended within a radio frame.

In a third aspect, the radio access network node is configured to selectively use one of a plurality of downlink DTX patterns, the plurality of downlink DTX patterns differing from one another in the number of subframes during which downlink transmission by the radio access network node is suspended within a radio frame.

In a fourth aspect, a method performed by a radio access network node includes selectively using one of a plurality of downlink DTX patterns, the plurality of downlink DTX patterns differing from one another in the number of subframes during which downlink transmission by the radio access network node is suspended within a radio frame.

In a fifth aspect, the wireless terminal is configured to receive configuration information from a radio access network node indicating a selected one of a plurality of downlink DTX patterns, and to receive downlink transmissions of the radio access network node based on the configuration information. The plurality of downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmissions by the radio access network node are suspended.

In a sixth aspect, a method performed by a wireless terminal includes receiving configuration information from a radio access network node indicating a selected one of a plurality of downlink DTX patterns, and receiving downlink transmissions of the radio access network node based on the configuration information. The plurality of downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmissions by the radio access network node are suspended.

In a seventh aspect, the program includes a set of instructions (software code) that, when loaded into a computer, causes the computer to perform a method according to any of the above aspects.

The above-mentioned aspects provide an apparatus, method, and program that contribute to solving at least one of the problems described above.

FIG. 1 illustrates an example configuration of a wireless communication system related to one or more embodiments. A flowchart illustrating an example of the operation of a control device (e.g., RAN controller) related to one or more embodiments. FIG. 2 is a sequence diagram illustrating an example of the operation of a UE, a RAN node, and a controller in accordance with one or more embodiments. FIG. 1 illustrates a number of example downlink DTX patterns, in accordance with one or more embodiments. FIG. 1 illustrates an example of suspending transmission within a subframe, in accordance with one or more embodiments. FIG. 1 illustrates an example of suspending transmission within a subframe, in accordance with one or more embodiments. 5 is a flow chart illustrating an example of the operation of a controller, in accordance with one or more embodiments. FIG. 1 illustrates an example of switching between multiple downlink DTX patterns, in accordance with one or more embodiments. FIG. 1 is a sequence diagram illustrating an example of signaling in accordance with one or more embodiments. FIG. 2 is a block diagram illustrating an example configuration of a UE in accordance with one or more embodiments. FIG. 1 is a block diagram illustrating an example configuration of a RAN node in accordance with one or more embodiments. FIG. 2 is a block diagram illustrating an example configuration of a control device according to one or more embodiments.

Below, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are given the same reference numerals, and duplicate explanations will be omitted as necessary for clarity of explanation.

The multiple embodiments described below may be used alone, or two or more embodiments may be combined as appropriate. These multiple embodiments may have novel features that are different from each other. Thus, these multiple embodiments may contribute to achieving different objectives or solving different problems, and may contribute to providing different effects.

The drawings are merely examples for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be appreciated by those skilled in the art, various features or steps described with reference to any one drawing may be combined with features or steps shown in one or more other figures to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessarily required to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

The embodiments described below are primarily directed to a 3GPP LTE (or E-UTRAN) system. However, these embodiments may also be applied to other wireless communication systems.

As used herein, depending on the context, "if" may be construed to mean "when," "while," "at or around the time," "after," "upon," "in response to determining," "in accordance with a determination," or "in response to detecting." These expressions may be construed to have the same meaning, depending on the context.

First, the configuration and operation of multiple network elements common to multiple embodiments will be described. FIG. 1 shows an example configuration of a wireless communication system related to multiple embodiments. Each element (network function) shown in FIG. 1 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

In the example of FIG. 1, the wireless communication system includes a number of UEs 1 and a Radio Access Network (RAN) node 2. In the following, when matters common to the multiple UEs 1 are described, reference will be made to the UE 1 unless otherwise specified. The UE 1 may be referred to as a wireless terminal, a mobile terminal, a mobile station, or other terms such as a wireless transmit receive unit (WTRU). The RAN node 2 may be referred to as a network, a base station, or a radio station. If the system of FIG. 1 is an LTE system, the RAN node 2 may be an eNB. The UE 1 has at least one radio transceiver and communicates with the RAN node 2. The RAN node 2 manages, operates, or provides a cell 21 and communicates with the multiple UEs 1 within the cell 21 using cellular communication technology (e.g., E-UTRA Radio Access Technology).

RAN node 2 may provide multiple cells including cell 21, and UE 1 may be simultaneously connected to multiple cells provided by RAN node 2. In other words, UE 1 may perform Carrier Aggregation (CA) between multiple cells provided by RAN node 2. In addition, UE 1 may be simultaneously connected to RAN node 2 and other RAN nodes for Dual Connectivity (DC).

The RAN node 2 may include a Base Band Unit (BBU) and one or more Remote Radio Heads (RRHs). The RRHs may also be referred to as Radio Units (RUs) or Transmission Reception Points (TRPs). The BBU may include a Central Unit (CU) and one or more Distributed Units (DUs). Depending on the functional division between the BBU and the RRHs, in one implementation the BBU may be the node hosting the Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), Medium Access Control (MAC), and higher physical (PHY) layers of the eNB. In other implementations, the BBU may perform all digital signal processing including lower PHY layer signal processing and Digital to Analog (DA) and Analog to Digital (AD) conversion. Each RRH may include RF components coupled to one or more antennas and may include lower PHY layer signal processing circuitry depending on the functional division of the BBU and the RRHs. The RF components include at least an amplifier and a frequency converter.

The RAN node 2 is connected to a RAN controller 3. The RAN controller 3 may be referred to as a control device or control system. The RAN controller 3 may be integrated in the RAN node 2 (e.g., eNB). Alternatively, the RAN controller 3 may include one or both of a Non-RT RIC and a Near-RT RIC as defined in the O-RAN Alliance technical specifications. In this case, the RAN node 2 may be connected to the RAN controller 3 via one or both of an O1 interface and an E2 interface. In accordance with the O-RAN architecture, the RAN node 2 may be referred to as an E2 node. Alternatively, the RAN controller 3 may be an Operations, Administration and Maintenance (OAM) server or other controller. In other words, the functionality of the RAN controller 3 may be located in the RAN node 2, a Non-RT RIC, a Near-RT RIC, an OAM server, or other controller, or may be distributed in any combination of these.

First Embodiment
A configuration example of the wireless communication system according to this embodiment is similar to the configuration example described with reference to FIG. 1. FIG. 2 shows an example of the operation of the RAN controller 3. In step 201, the RAN controller 3 selects one of a plurality of downlink (DL) DTX patterns. Here, the plurality of DL DTX patterns are different from each other in the number of subframes in which DL transmission by the RAN node 2 is stopped in one radio frame. In step 201, the RAN controller 3 applies the selected DL DTX pattern to the RAN node 2. In other words, the RAN node 2 selectively uses one of the plurality of DL DTX patterns. Depending on some condition, for example, but not limited to, depending on the state of power supply to the RAN node 2, the RAN node 2 may selectively use the plurality of DL DTX patterns. Additionally or alternatively, the RAN node 2 may selectively use the plurality of DL DTX patterns depending on the number of UEs 1 that are active (or in RRC_CONNECTED state) in the cell 21. Additionally or alternatively, the RAN node 2 may selectively use the plurality of DL DTX patterns depending on the time period. Additionally or alternatively, the RAN node 2 may selectively use DL DTX patterns depending on the location of the RAN node 2 or cell 21.

The operation of the RAN controller 3 described with reference to FIG. 2 enables the RAN node 2 to use one selected from a number of DL DTX patterns, each of which differs in the number of subframes in which DL transmission by the RAN node 2 is stopped within a radio frame.

Figure 3 shows an example of the operation of the UE 1, the RAN node 2 and the RAN controller 3. In step 301, the RAN controller 3 sends an indication, instruction or request to the RAN node 2 to activate a power saving mode. The indication, instruction or request may indicate a change from one power saving mode to another. The indication, instruction or request indicates a selected one of a number of DL DTX patterns. The RAN node 2 applies the DL DTX pattern indicated by the RAN controller 3 to the cell 21.

In step 302, the RAN node 2 transmits configuration information to the UE 1 indicating a selected one of the multiple DL DTX patterns. The configuration information may be referred to as subframe allocation configuration. The RAN node 2 may broadcast the configuration information in the cell 21. More specifically, the RAN node 2 may broadcast the configuration information in the cell 21 via cell-specific (or cell-common) RRC signaling. The cell-specific (or cell-common) RRC signaling may be system information, specifically a Master Information Block (MIB) or a SIB. The configuration information (e.g., MBSFN configuration) may be broadcast in a SIB Type 2 (SIB2). Additionally or alternatively, the RAN node 2 may signal the configuration information in a UE-specific RRC signaling. Additionally or alternatively, the RAN node 2 may signal the configuration information in Layer 2 or Layer 1 control information (e.g., Downlink control information (DCI)). UE 1 receives the downlink transmission of RAN node 2 based on the received configuration information. Specifically, UE 1 may receive the downlink transmission of RAN node 2 according to the DL DTX pattern indicated by the configuration information.

The operation of the UE 1, RAN node 2 and RAN controller 3 described with reference to Figure 3 enables the RAN node 2 to use one selected from a number of DL DTX patterns, each of which differs in the number of subframes in a radio frame during which DL transmissions by the RAN node 2 are suspended. This then enables the UE 1 to receive DL transmissions in accordance with that DL DTX pattern.

Note that the operation shown in FIG. 3 is an example and may be modified as appropriate. In particular, step 302 may be omitted. In other words, the RAN node 2 may not transmit configuration information indicating a selected one of multiple DL DTX patterns to the UE 1. This can contribute to reducing the power consumption of the RAN node 2 without adding new functions to the UE 1. The UE 1 may perform normal reception operation regardless of whether cell DTX is performed in the cell 21 or not. In one example, as described below, each DL DTX pattern may be related to the number and arrangement of MBSFN subframes in a radio frame. In this case, the RAN node 2 may transmit to the UE 1 a normal MBSFN configuration corresponding to the selected DL DTX pattern. The normal MBSFN configuration is used by the UE 1 to know the arrangement of the MBSFN subframes, but does not need to indicate that DL DTX is performed in any of the MBSFN subframes (and unicast subframes).

In the case of an LTE system, one radio frame consists of 10 subframes and may include multiple unicast subframes and one or more multicast/broadcast subframes. The multicast/broadcast subframes are MBSFN subframes. In one implementation, the RAN node 2 performs cell DTX operation by stopping DL transmission in one or more multicast/broadcast subframes in a radio frame, i.e., one or more MBSFN subframes. The RAN node 2 stops transmitting CRS and other physical signals and channels in the MBSFN subframes. The UE 1 stops downlink reception of CRS and other physical signals and channels from the RAN node 2 in the MBSFN subframes. The MBSFN subframes in which DL transmission is stopped may be referred to as blank subframes or DTX subframes.

Figure 4 shows examples of multiple DL DTX patterns. In the example of Figure 4, the RAN node 2 selectively uses one of five DL DTX patterns A to E. The DL DTX patterns A to E differ from each other in the number of MBSFN subframes (where DL transmission is stopped) in one radio frame. That is, in the example of Figure 4, the RAN node 2 (and the RAN controller 3) switches between the five DL DTX patterns by changing the ratio of unicast subframes to MBSFN subframes in a radio frame. Patterns A, B, C, D, and E have 2, 3, 4, 5, and 6 MBSFN subframes, respectively, in one radio frame, and DL transmission is stopped in the MBSFN subframes. Therefore, the energy saving effect is highest in the order of DL DTX patterns E, D, C, B, and A.

For example, depending on the state of power supply to RAN node 2, RAN node 2 may selectively use one of DL DTX patterns A to E. If RAN node 2 is connected to an external power source and receives power from the external power source, RAN node 2 may not use MBSFN subframes and all subframes in the radio frame may be unicast subframes. On the other hand, if RAN node 2 (or some of its components) is not powered by an external power source and is running on an emergency battery, RAN node 2 may use any of DL DTX patterns A to E. Depending on the remaining charge of the emergency battery, RAN node 2 may use a DL DTX pattern that is more energy-efficient.

In another example, the RAN node 2 may selectively use one of the DL DTX patterns A to E depending on the number of UEs 1 that are active (or in RRC_CONNECTED state) in the cell 21. As the number of active UEs 1 in the cell 21 decreases, the RAN node 2 may use a more energy-efficient DL DTX pattern.

Figure 4 shows switching between five DL DTX patterns, but this is just one example. The RAN node 2, or the RAN node 2 and UE 1, may selectively use fewer than five DL DTX patterns or more than five DL DTX patterns. In a given DL DTX pattern, there may be only one MBSFN subframe (where DL transmission is stopped) in a radio frame, or there may be seven or more MBSFN subframes (where DL transmission is stopped) in a radio frame.

Additionally or alternatively, in some implementations, to further enhance energy savings, the RAN node 2 may stop DL transmission in at least one of the multiple unicast subframes in the radio frame. In some implementations, the RAN node 2 may switch between at least two of the multiple DL DTX patterns by changing the number of unicast subframes in the radio frame in which DL transmission by the RAN node 2 is stopped.

Specifically, the RAN node 2 (and the RAN controller 3) may stop DL transmissions in one or more multicast/broadcast subframes (e.g., MBSFN subframes) within a radio frame, and may also stop DL transmissions in at least one of multiple unicast subframes within that radio frame.

In other words, the multiple DL DTX patterns may include a first pattern in which downlink transmissions are stopped in multicast/broadcast subframes (e.g., MBSFN subframes) and a second pattern in which downlink transmissions are stopped in unicast subframes. In the first pattern, downlink transmissions are stopped in one or more multicast/broadcast subframes (e.g., MBSFN subframes) in a radio frame. In the second pattern, downlink transmissions are stopped in one or more unicast subframes in the radio frame in addition to one or more multicast/broadcast subframes. Additionally or additionally, downlink transmissions may be stopped in one or more unicast subframes in the radio frame.

Similarly, UE 1 may stop DL reception in at least one of the multiple unicast subframes in a radio frame. However, as described above, UE 1 may perform normal reception operation regardless of whether cell DTX is performed in cell 21. Specifically, UE 1 may attempt to receive physical signals and channels, e.g., PDCCH reception, in a unicast subframe regardless of whether DL transmission is stopped in that unicast subframe.

Figures 5 and 6 show examples of DL transmission stop in unicast subframes. RAN node 2 may stop DL transmission as shown in either Figure 5 or Figure 6, or may stop DL transmission as shown in both Figure 5 and Figure 6. Similarly, UE 1 may stop receiving DL transmission as shown in either Figure 5 or Figure 6, or may stop receiving DL transmission as shown in both Figure 5 and Figure 6.

In the example of FIG. 5, among the ten subframes (subframes #0 to #9) in a radio frame, DL transmission is stopped in one or both of the fifth subframe (i.e., subframe #4) and the tenth subframe (i.e., subframe #9). Subframes #4 and #9 are unicast subframes in which neither PSS nor SSS is transmitted. Typically, in subframes #4 and #9, CRS is always transmitted in multiple resource elements in the first and fifth OFDM symbols of each of the first and second slots. In addition, PDCCH and Physical Downlink Shared Channel (PDSCH) may be transmitted in subframes #4 and #9. In one or more DL DTX patterns, the RAN node 2 may stop transmitting CRS and other physical signals and channels (e.g., PDCCH and PDSCH) in unicast subframes #4 and #9.

In the example of FIG. 6, among the ten subframes (subframes #0 to #9) in a radio frame, DL transmission is stopped in one or both of the first subframe (i.e., subframe #0) and the sixth subframe (i.e., subframe #5). Subframes #0 and #5 are unicast subframes in which the PSS and SSS are transmitted and the Physical Broadcast Channel (PBCH) carrying the MIB is transmitted. Typically, in subframes #0 and #5, the CRS is always transmitted in multiple resource elements in the first and fifth OFDM symbols of each of the first and second slots. In addition, typically, in subframes #0 and #5, the PSS is always transmitted in the seventh OFDM symbol of the first slot and the SSS is always transmitted in the sixth OFDM symbol of the first slot. Furthermore, typically, in subframes #0 and #5, the PBCH is always transmitted in the first to fourth OFDM symbols of the second slot. Furthermore, typically, in subframe #5, a PDSCH carrying SIB1 is transmitted every two radio frames. In subframes #0 and #5, a PDCCH and a PDSCH can be transmitted.

In one or more DL DTX patterns, the RAN node 2 may stop transmitting CRS and other physical signals and channels (e.g., PSS, SSS, PBCH, PDCCH, and PDSCH) in one or both of the unicast subframes #0 and #5. Note that PSS, SSS, MIB (PBCH), and SIB1 transmissions are necessary for the UE 1 to synchronize to and access the cell 21. Therefore, the RAN node 2 may stop transmitting PSS, SSS, MIB (PBCH), and SIB1 in some radio frames by making the periodicity or cycle of PSS, SSS, MIB (PBCH), and SIB1 transmissions longer than their normal reference values.

Second Embodiment
A configuration example of the wireless communication system according to this embodiment is similar to the configuration example described with reference to Fig. 1. Fig. 7 shows an example of the operation of the RAN controller 3. In step 701, the RAN controller 3 monitors the state of power supply to the RAN node 2. The RAN controller 3 may monitor the state of power supply to some components (e.g., BBU, CU, DU, or RRH) of the RAN node 2. In step 702, the RAN controller 3 selects one of multiple downlink DTX patterns to be applied to the RAN node 2 according to the state of power supply to the RAN node 2 (or some components thereof). Specific examples of the multiple downlink DTX patterns may be similar to those described in the first embodiment. The operation of the RAN controller 3 described with reference to Fig. 7 enables the RAN node 2 to selectively use multiple downlink DTX patterns according to the state of power supply to the RAN node 2.

Figure 8 shows an example of changing the DL DTX pattern depending on the state of power supply to the RAN node 2. In the example of Figure 8, the RAN node 2 switches its power saving mode between four modes, specifically no restriction mode 801, restricted unicast mode 802, restricted mobility mode 803, and emergency mode 804. As described below, three of the four power saving modes, modes 802 to 804, are associated with different DL DTX patterns.

When the RAN node 2 (or some of its components) is connected to an external power source and is supplied with power from the external power source, the RAN controller 3 applies the unrestricted mode 801 to the RAN node 2. In the unrestricted mode 801, the ratio of unicast subframes to MBSFN subframes in a radio frame is 10:0. That is, in the unrestricted mode 801, all 10 subframes in a radio frame are unicast subframes, and cell DTX operation for energy saving is not performed. Also, in the unrestricted mode 801, the transmission cycle or period of the PSS, SSS, MIB, and SIB1 is normal and is not changed.

If the RAN node 2 (or some of its components) is not powered by an external power source and is running on an emergency battery, the RAN controller 3 applies the restricted unicast mode 802, the restricted mobility mode 803, or the emergency mode 804 to the RAN node 2. The RAN controller 3 selects one of the restricted unicast mode 802, the restricted mobility mode 803, and the emergency mode 804 according to the remaining capacity of the emergency battery. In one example, if the remaining battery capacity is 50% or more, the RAN controller 3 may select the restricted unicast mode 802. If the remaining battery capacity falls below 50%, the RAN controller 3 may select the restricted mobility mode 803. If the remaining battery capacity decreases further and is close to running out (e.g., the remaining battery capacity is less than 10%), the RAN controller 3 may select the emergency mode 804.

In restricted unicast mode 802, for example, the ratio of unicast subframes to MBSFN subframes in a radio frame is 6:4. RAN node 2 performs cell DTX operation by stopping DL transmission in four MBSFN subframes in a radio frame. In restricted unicast mode 802, the transmission cycle or period of PSS, SSS, MIB, and SIB1 is normal and is not changed. Therefore, RAN node 2 continues DL transmission in all unicast subframes.

In restricted mobility mode 803, the number of MBSFN subframes in a radio frame is greater than that in restricted unicast mode 802. In other words, in restricted mobility mode 803, the number of unicast subframes in a radio frame is smaller than that in restricted unicast mode 802. For example, in restricted mobility mode 803, the ratio of unicast subframes to MBSFN subframes in a radio frame is 4:6. The RAN node 2 performs cell DTX operation by stopping DL transmission in six MBSFN subframes in a radio frame. In addition, in restricted mobility mode 803, the RAN node 2 extends the transmission cycle of PSS, SSS, MIB, and SIB1 to twice the normal cycle. And, the RAN node 2 stops DL transmission in unicast subframes in which none of PSS, SSS, MIB, and SIB1 is transmitted.

In the emergency mode 804, the number of MBSFN subframes in a radio frame is greater than that in the restricted unicast mode 802. In other words, in the emergency mode 804, the number of unicast subframes in a radio frame is less than that in the restricted unicast mode 802. For example, in the emergency mode 804, the ratio of unicast subframes to MBSFN subframes in a radio frame is 4:6, similar to that in the restricted mobility mode 803. The RAN node 2 performs cell DTX operation by stopping DL transmission in six MBSFN subframes in a radio frame. In addition, in the restricted mobility mode 804, the RAN node 2 extends the transmission cycle of PSS, SSS, MIB, and SIB1 to four times that in normal mode. And, the RAN node 2 stops DL transmission in unicast subframes in which none of PSS, SSS, MIB, and SIB1 is transmitted.

The ratio of unicast subframes to MBSFN subframes in a radio frame for each mode shown in FIG. 8 is merely an example. Similarly, the transmission periods of PSS, SSS, MIB, and SIB1 for each mode shown in FIG. 8 are also merely an example. These may be defined so that the number of subframes in which DL transmission is performed within one radio frame decreases in the order of modes 801, 802, 803, and 804.

It should also be understood that the names of the four power saving modes 801-804 shown in FIG. 8 are merely examples. These four power saving modes 801-804 may be referred to by other names, for example, a first, second, third, and fourth power mode. Power saving mode 801 may be referred to as a normal mode or a non-power saving mode. The RAN node 2 may use fewer than four power saving modes or more than four power saving modes.

FIG. 9 shows an example of signaling for activating, deactivating or changing a power saving mode. In step 901, the RAN controller 3 receives a power supply status report from the battery controller 7. The battery controller 7 manages the power supply to the RAN node 2 (or some of its components). The power supply status report indicates the status of the power supply to the RAN node 2 (or some of its components). The power supply status report may indicate whether the RAN node 2 is powered from an external power source. Additionally or alternatively, the power supply status report may indicate the remaining charge of a battery supplying power to the RAN node 2. Additionally or alternatively, the power supply status report may indicate whether any failure has occurred in the power supply to the RAN node 2. In one example, the power supply status report may indicate any of the power supply statuses described with reference to FIG. 8.

In step 902, the RAN controller 3 sends an indication, instruction, or request to the RAN node 2 to activate, deactivate, or change the power saving mode. More specifically, in the example of FIG. 9, the RAN controller 3 sends the indication, instruction, or request to the BBU 23 of the RAN node 2. The RAN controller 3 may decide to activate, deactivate, or change the power saving mode based on the power supply status report.

In step 903, the BBU 23 of the RAN node 2 instructs the RU 25 to update (activate, deactivate, or change) the power saving mode. The BBU 23 may provide the RU 25 with a subframe allocation setting corresponding to the applied power saving mode or DL DTX pattern.

In step 904, the BBU 23 of the RAN node 2 transmits to the UE 1 a subframe allocation configuration corresponding to the applied power saving mode or DL DTX pattern. The RAN node 2 may broadcast the configuration in the cell 21 via cell-specific (or cell-wide) RRC signaling. The configuration may be an MBSFN configuration and the RAN node 2 may broadcast the configuration in SIB2. Additionally or alternatively, the RAN node 2 may signal the configuration information in UE-specific RRC signaling. Additionally or alternatively, the RAN node 2 may signal the configuration information in layer 2 or layer 1 control information (e.g., DCI). The UE 1 receives the downlink transmission of the RAN node 2 based on the received subframe allocation configuration. Specifically, the UE 1 receives the downlink transmission of the RAN node 2 according to the DL DTX pattern indicated by the subframe allocation configuration.

Note that the operation shown in FIG. 9 is an example and may be modified as appropriate. In particular, step 904 may be omitted. In other words, the RAN node 2 may not transmit to the UE 1 a subframe allocation configuration corresponding to the applied power saving mode or DL DTX pattern. This can contribute to reducing the power consumption of the RAN node 2 without adding new functions to the UE 1. The UE 1 may perform normal reception operation regardless of whether cell DTX is performed in the cell 21 or not. In one example, the RAN node 2 may transmit to the UE 1 a normal MBSFN configuration corresponding to the selected DL DTX pattern. The normal MBSFN configuration is used by the UE 1 to know the arrangement of the MBSFN subframes, but does not need to indicate that DL DTX is performed in any of the MBSFN subframes (and unicast subframes).

Next, configuration examples of the UE 1, RAN node 2, and RAN controller 3 relating to the above-mentioned embodiments will be described below. FIG. 10 is a block diagram showing a configuration example of the UE 1. The RF transceiver 1001 performs analog RF signal processing to communicate with the RAN node 2. The RF transceiver 1001 may include multiple transceivers. The analog RF signal processing performed by the RF transceiver 1001 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 1001 is coupled to the antenna array 1002 and the baseband processor 1003. The RF transceiver 1001 receives modulation symbol data (or OFDM symbol data) from the baseband processor 1003, generates a transmit RF signal, and supplies the transmit RF signal to the antenna array 1002. The RF transceiver 1001 also generates a baseband receive signal based on the receive RF signal received by the antenna array 1002, and supplies the baseband receive signal to the baseband processor 1003. The RF transceiver 1001 may include an analog beamformer circuit for beamforming. The analog beamformer circuit may include, for example, multiple phase shifters and multiple power amplifiers.

The baseband processor 1003 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression/decompression, (b) data segmentation/concatenation, (c) generation/decomposition of transmission formats (transmission frames), (d) transmission path coding/decoding, (e) modulation (symbol mapping)/demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) using Inverse Fast Fourier Transform (IFFT). Meanwhile, control plane processing includes communication management of Layer 1 (e.g., transmit power control), Layer 2 (e.g., radio resource management and hybrid automatic repeat request (HARQ) processing), and Layer 3 (e.g., signaling related to attachment, mobility, and call management).

For example, the digital baseband signal processing by the baseband processor 1003 may include signal processing of the PDCP layer, the RLC layer, the MAC layer, and the PH layer. Also, the control plane processing by the baseband processor 1003 may include processing of the Non-Access Stratum (NAS) protocol, the RRC protocol, MAC Control Elements (CEs), and Downlink Control Information (DCIs).

The baseband processor 1003 may perform MIMO encoding and precoding for beamforming.

The baseband processor 1003 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1004 described below.

The application processor 1004 is also called a CPU, MPU, microprocessor, or processor core. The application processor 1004 may include multiple processors (multiple processor cores). The application processor 1004 realizes various functions of the UE 1 by executing a system software program (Operating System (OS)) and various application programs (e.g., a calling application, a web browser, a mailer, a camera operation application, a music playback application) read from the memory 1006 or other memories.

In some implementations, the baseband processor 1003 and the application processor 1004 may be integrated on a single chip, as shown by the dashed line (1005) in FIG. 10. In other words, the baseband processor 1003 and the application processor 1004 may be implemented as a single System on Chip (SoC) device 1005. An SoC device is sometimes called a system Large Scale Integration (LSI) or chipset.

The memory 1006 is a volatile memory or a non-volatile memory or a combination thereof. The memory 1006 may include multiple physically independent memory devices. The volatile memory may be, for example, a Static Random Access Memory (SRAM) or a Dynamic RAM (DRAM) or a combination thereof. The non-volatile memory may be a Mask Read Only Memory (MROM), an Electrically Erasable Programmable ROM (EEPROM), a flash memory, or a hard disk drive, or any combination thereof. For example, the memory 1006 may include an external memory device accessible from the baseband processor 1003, the application processor 1004, and the SoC 1005. The memory 1006 may include an embedded memory device integrated within the baseband processor 1003, the application processor 1004, or the SoC 1005. Additionally, the memory 1006 may include a memory within a Universal Integrated Circuit Card (UICC).

The memory 1006 may store one or more software modules (computer programs) 1007 that include instructions and data for processing by the UE 1. In some implementations, the baseband processor 1003 or the application processor 1004 may be configured to read and execute the software modules 1007 from the memory 1006 to perform processing for the UE 1 as described in one or more of the embodiments.

The control plane processing and operations performed by the UE 1 described in the above embodiment can be realized by elements other than the RF transceiver 1001 and the antenna array 1002, namely at least one of the baseband processor 1003 and the application processor 1004, and the memory 1006 storing the software module 1007.

FIG. 11 is a block diagram showing an example of the configuration of a RAN node 2. Referring to FIG. 11, the RAN node 2 includes an RF transceiver 1101, a network interface 1103, a processor 1104, and a memory 1105. The RF transceiver 1101 performs analog RF signal processing to communicate with the UEs 1. The RF transceiver 1101 may include multiple transceivers. The RF transceiver 1101 is coupled to an antenna array 1102 and a processor 1104. The RF transceiver 1101 receives modulation symbol data from the processor 1104, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 1102. The RF transceiver 1101 also generates a baseband receive signal based on the receive RF signal received by the antenna array 1102, and provides the baseband receive signal to the processor 1104. The RF transceiver 1101 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, multiple phase shifters and multiple power amplifiers.

The network interface 1103 is used to communicate with network nodes (e.g., other RAN nodes, as well as control and forwarding nodes of the core network). The network interface 1103 may include, for example, an IEEE 802.3 series compliant network interface card (NIC).

The processor 1104 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The processor 1104 may include multiple processors. For example, the processor 1104 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing. The processor 1104 may include a digital beamformer module for beamforming. The digital beamformer module may include a MIMO encoder and a precoder.

Memory 1105 is composed of a combination of volatile memory and non-volatile memory. Volatile memory is, for example, SRAM or DRAM, or a combination of these. Non-volatile memory is MROM, EEPROM, flash memory, or a hard disk drive, or any combination of these. Memory 1105 may include storage located remotely from processor 1104. In this case, processor 1104 may access memory 1105 via network interface 1103 or other I/O interface.

The memory 1105 may store one or more software modules (computer programs) 1106 including instructions and data for processing by the RAN node 2. In some implementations, the processor 1104 may be configured to read the software modules 1106 from the memory 1105 and execute them to perform the processing of the RAN node 2 described in one or more of the embodiments.

FIG. 12 is a block diagram showing an example configuration of the RAN controller 3. In the example of FIG. 12, the RAN controller 3 is implemented as a computer system. The computer system includes one or more processors 1210, memory 1220, and mass storage 1230, which communicate with each other via a bus 1270. The one or more processors 1210 may include, for example, a CPU or a Graphics Processing Unit (GPU) or both. The computer system may include other devices such as one or more output devices 1240, one or more input devices 1250, and one or more peripherals 1260. The one or more peripherals 1260 may include a modem, or a network adapter, or any combination thereof.

Memory 1220 and/or mass storage 1230 may include a computer-readable medium having stored thereon one or more sets of instructions. These instructions may be located partially or completely in memory within one or more processors 1210. These instructions, when executed in one or more processors 1210, cause the one or more processors 1210 to provide the functionality of the RAN controller 3 described in the above embodiments.

As described with reference to Figures 10, 11 and 12, each of the processors in the UE 1, RAN node 2 and RAN controller 3 in the above-described embodiments may execute one or more programs including instructions for causing a computer to perform the algorithms described with reference to the drawings. The programs include instructions (or software code) for causing a computer to perform one or more functions described in the embodiments when loaded into the computer. The programs may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The programs may be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

The above-described embodiments are merely examples of the application of the technical ideas obtained by the inventors. In other words, the technical ideas are not limited to the above-described embodiments, and various modifications are of course possible.

For example, some or all of the above embodiments may be described as, but are not limited to, the following appendices. Some or all of the elements (e.g., configurations and functions) described in appendices directed to devices (e.g., control devices) may naturally be described as appendices directed to methods and programs. For example, some or all of the elements described in appendices 2-15, which are subordinate to appendices 1, may also be described as appendices subordinate to appendices 28 and 31, due to the same subordinate relationship as appendices 2-15. Similarly, some or all of the elements described in appendices 18-27, which are subordinate to appendices 17, may also be described as appendices subordinate to appendices 30 and 33, due to the same subordinate relationship as appendices 18-27. Some or all of the elements described in any appendice may be applied to various hardware, software, recording means for recording software, systems, and methods.

(Appendix 1)
means for selectively applying one of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network node;
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
Control device.
(Appendix 2)
the radio frame comprises a plurality of unicast subframes and one or more multicast/broadcast subframes;
2. The control device of claim 1.
(Appendix 3)
the plurality of downlink DTX patterns include a first pattern in which downlink transmission in the one or more multicast/broadcast subframes is stopped, and a second pattern in which downlink transmission in one or more unicast subframes in addition to the one or more multicast/broadcast subframes is stopped.
3. The control device of claim 2.
(Appendix 4)
At least one of the downlink DTX patterns causes the radio access network node to stop transmitting Cell-specific Reference Signals (CRS) and other physical signals and channels in at least one of the one or more multicast/broadcast subframes.
4. The control device according to claim 2 or 3.
(Appendix 5)
At least one of the downlink DTX patterns causes the radio access network node to stop downlink transmissions in at least one of the unicast subframes in addition to stopping downlink transmissions in the one or more multicast/broadcast subframes.
5. The control device according to any one of claims 2 to 4.
(Appendix 6)
the applying means is configured to switch between at least two of the plurality of downlink DTX patterns by changing a ratio of unicast and multicast/broadcast subframes within the radio frame.
6. The control device according to any one of appendix 2 to 5.
(Appendix 7)
the applying means being configured to switch between at least two of the downlink DTX patterns by varying a number of unicast subframes within the radio frame during which downlink transmission by the radio access network node is suspended.
7. The control device according to any one of claims 2 to 6.
(Appendix 8)
At least one of the plurality of downlink DTX patterns causes the radio access network node to stop downlink transmissions in remaining unicast subframes of the plurality of unicast subframes, except for a plurality of specific unicast subframes in which a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) are transmitted.
8. The control device according to any one of claims 2 to 7.
(Appendix 9)
At least one of the plurality of downlink DTX patterns causes the radio access network node to stop downlink transmission in at least one particular unicast subframe in which a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) are transmitted.
9. The control device according to any one of claims 2 to 8.
(Appendix 10)
At least one of the plurality of downlink DTX patterns causes the radio access network node to stop downlink transmission in the at least one particular unicast subframe by lengthening a transmission period of the PSS and the SSS longer than a reference value.
10. The control device of claim 9.
(Appendix 11)
the radio frame is a Long Term Evolution (LTE) radio frame,
each of the one or more multicast/broadcast subframes is a Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) subframe;
11. The control device according to any one of appendix 2 to 10.
(Appendix 12)
means for selecting one of the plurality of downlink DTX patterns to be applied to the radio access network node depending on a state of power supply to the radio access network node,
12. The control device according to any one of claims 1 to 11.
(Appendix 13)
The control device is located in the radio access network node.
13. The control device according to any one of appendix 1 to 12.
(Appendix 14)
The control device is located in an Open Radio Access Network (O-RAN) Non-Real-Time (Non-RT) RIC or an O-RAN Near-Real-Time (Near-RT) RIC.
13. The control device according to any one of appendix 1 to 12.
(Appendix 15)
the control device being located in an Operations, Administration and Maintenance (OAM) server or other controller coupled to the radio access network node;
13. The control device according to any one of appendix 1 to 12.
(Appendix 16)
A radio access network node comprising a control device according to any one of supplements 1 to 12.
(Appendix 17)
means for receiving configuration information from a radio access network node indicating a selected one of a plurality of downlink discontinuous transmission (DTX) patterns;
means for receiving a downlink transmission of the radio access network node based on the configuration information;
Equipped with
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
Wireless terminal.
(Appendix 18)
the radio frame comprises a plurality of unicast subframes and one or more multicast/broadcast subframes;
18. The wireless terminal of claim 17.
(Appendix 19)
the plurality of downlink DTX patterns include a first pattern in which downlink transmission in the one or more multicast/broadcast subframes is stopped, and a second pattern in which downlink transmission in one or more unicast subframes in addition to the one or more multicast/broadcast subframes is stopped.
19. The wireless terminal of claim 18.
(Appendix 20)
At least one of the plurality of downlink DTX patterns causes the wireless terminal to stop downlink reception of Cell-specific Reference Signals (CRS) and other physical signals and channels from the radio access network node in at least one of the one or more multicast/broadcast subframes.
20. The wireless terminal of claim 18 or 19.
(Appendix 21)
at least one of the plurality of downlink DTX patterns causes the wireless terminal to stop downlink reception from the radio access network node in at least one of the plurality of unicast subframes in addition to stopping downlink reception from the radio access network node in the one or more multicast/broadcast subframes.
21. The wireless terminal according to any one of appendix 18 to 20.
(Appendix 22)
switching between at least two of the plurality of downlink DTX patterns by changing a ratio of unicast and multicast/broadcast subframes within the radio frame;
22. The wireless terminal according to any one of appendix 18 to 21.
(Appendix 23)
switching between at least two of the plurality of downlink DTX patterns by varying within the radio frame a number of unicast subframes during which downlink transmission by the radio access network node is suspended.
23. The wireless terminal according to any one of appendix 18 to 22.
(Appendix 24)
At least one of the plurality of downlink DTX patterns causes the wireless terminal to stop downlink reception from the radio access network node in remaining unicast subframes of the plurality of unicast subframes, except for a plurality of specific unicast subframes in which a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) are transmitted.
24. The wireless terminal according to any one of appendix 18 to 23.
(Appendix 25)
At least one of the plurality of downlink DTX patterns causes the wireless terminal to stop downlink reception from the radio access network node in at least one particular unicast subframe in which a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) are transmitted.
25. The wireless terminal according to any one of appendix 18 to 24.
(Appendix 26)
At least one of the plurality of downlink DTX patterns causes the wireless terminal to stop downlink reception from the radio access network node in the at least one particular unicast subframe by lengthening a transmission period of the PSS and the SSS longer than a reference value.
26. The wireless terminal of claim 25.
(Appendix 27)
the radio frame is a Long Term Evolution (LTE) radio frame,
each of the one or more multicast/broadcast subframes is a Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) subframe;
27. A wireless terminal according to any one of appendix 18 to 26.
(Appendix 28)
selectively applying one of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network node;
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
A method performed by a control device.
(Appendix 29)
1. A method performed by a radio access network node, comprising:
selectively using one of a plurality of downlink discontinuous transmission (DTX) patterns;
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended.
(Appendix 30)
receiving configuration information from a radio access network node indicating a selected one of a plurality of downlink discontinuous transmission (DTX) patterns; and receiving a downlink transmission of the radio access network node based on the configuration information;
Equipped with
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
A method performed by a wireless terminal.
(Appendix 31)
A program for causing a computer to execute a method for a control device,
The method comprises selectively applying one of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network node;
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended.
(Appendix 32)
A program for causing a computer to perform a method for a radio access network node, comprising:
The method comprises selectively using one of a plurality of downlink discontinuous transmission (DTX) patterns;
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended.
(Appendix 33)
A program for causing a computer to perform a method for a wireless terminal, comprising:
The method comprises:
receiving configuration information from a radio access network node indicating a selected one of a plurality of downlink discontinuous transmission (DTX) patterns; and receiving a downlink transmission of the radio access network node based on the configuration information;
Equipped with
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended.

This application claims priority based on Japanese Patent Application No. 2024-002890, filed on January 11, 2024, the entire disclosure of which is incorporated herein by reference.

1 UE
2 RAN node 3 RAN controller 7 Battery controller 21 Cell 23 BBU
25 RU
1003 Baseband processor 1004 Application processor 1006 Memory 1007 Modules
1104 processor 1105 memory 1106 modules
1210 Processor 1220 Memory 1230 Mass storage

Claims (20)

means for selectively applying one of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network node;
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
Control device. the radio frame comprises a plurality of unicast subframes and one or more multicast/broadcast subframes;
The control device according to claim 1 . the plurality of downlink DTX patterns include a first pattern in which downlink transmission in the one or more multicast/broadcast subframes is stopped, and a second pattern in which downlink transmission in one or more unicast subframes in addition to the one or more multicast/broadcast subframes is stopped.
The control device according to claim 2. At least one of the downlink DTX patterns causes the radio access network node to stop transmitting Cell-specific Reference Signals (CRS) and other physical signals and channels in at least one of the one or more multicast/broadcast subframes.
The control device according to claim 2 or 3. At least one of the downlink DTX patterns causes the radio access network node to stop downlink transmissions in at least one of the unicast subframes in addition to stopping downlink transmissions in the one or more multicast/broadcast subframes.
The control device according to any one of claims 2 to 4. the applying means is configured to switch between at least two of the plurality of downlink DTX patterns by changing a ratio of unicast and multicast/broadcast subframes within the radio frame.
The control device according to any one of claims 2 to 5. the applying means being configured to switch between at least two of the downlink DTX patterns by varying a number of unicast subframes within the radio frame during which downlink transmission by the radio access network node is suspended.
The control device according to any one of claims 2 to 6. At least one of the plurality of downlink DTX patterns causes the radio access network node to stop downlink transmissions in remaining unicast subframes of the plurality of unicast subframes, except for a plurality of specific unicast subframes in which a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) are transmitted.
The control device according to any one of claims 2 to 7. At least one of the plurality of downlink DTX patterns causes the radio access network node to stop downlink transmission in at least one particular unicast subframe in which a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) are transmitted.
The control device according to any one of claims 2 to 8. At least one of the plurality of downlink DTX patterns causes the radio access network node to stop downlink transmission in the at least one particular unicast subframe by lengthening a transmission period of the PSS and the SSS longer than a reference value.
The control device according to claim 9. the radio frame is a Long Term Evolution (LTE) radio frame,
each of the one or more multicast/broadcast subframes is a Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) subframe;
The control device according to any one of claims 2 to 10. means for selecting one of the plurality of downlink DTX patterns to be applied to the radio access network node depending on a state of power supply to the radio access network node,
The control device according to any one of claims 1 to 11. The control device is located in the radio access network node.
The control device according to any one of claims 1 to 12. The control device is located in an Open Radio Access Network (O-RAN) Non-Real-Time (Non-RT) RIC or an O-RAN Near-Real-Time (Near-RT) RIC.
The control device according to any one of claims 1 to 12. means for receiving configuration information from a radio access network node indicating a selected one of a plurality of downlink discontinuous transmission (DTX) patterns;
means for receiving a downlink transmission of the radio access network node based on the configuration information;
Equipped with
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
Wireless terminal. selectively applying one of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network node;
the downlink DTX patterns differ from one another in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended;
A method performed by a control device. 1. A method performed by a radio access network node, comprising:
selectively using one of a plurality of downlink discontinuous transmission (DTX) patterns;
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended. A program for causing a computer to execute a method for a control device,
The method comprises selectively applying one of a plurality of downlink discontinuous transmission (DTX) patterns to a radio access network node;
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended. A program for causing a computer to perform a method for a radio access network node, comprising:
The method comprises selectively using one of a plurality of downlink discontinuous transmission (DTX) patterns;
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended. A program for causing a computer to perform a method for a wireless terminal, comprising:
The method comprises:
receiving configuration information from a radio access network node indicating a selected one of a plurality of downlink discontinuous transmission (DTX) patterns; and receiving a downlink transmission of the radio access network node based on the configuration information;
Equipped with
The multiple downlink DTX patterns differ from each other in the number of subframes in a radio frame during which downlink transmission by the radio access network node is suspended.