JP6976677B2 - Wireless base station and communication control method - Google Patents

Description

The present invention relates to a radio base station and a communication control method that include an overhang device and a centralized device and perform wireless communication with a user device.

The 3rd Generation Partnership Project (3GPP) specifies LTE-Advanced (hereinafter referred to as LTE including LTE-Advanced) for the purpose of further speeding up the Long Term Evolution (LTE). Further, in 3GPP, specifications of a successor system of LTE called 5G (5th generation mobile communication system) and the like are being studied.

LTE includes a so-called C-RAN (Centralized Radio Access Network) that includes a centralized device having a scheduler function (MAC scheduler) in the MAC layer and an overhanging device that overhangs from the installation location of the centralized device and is arranged remotely. A type of radio base station is used. The overhanging device includes a radio unit (RF unit) such as a PA (Power Amplifier) / LNA (Low Noise Amplifier), a radio transmission / reception module, and a modulation / demodulation module. The central centralizing device and the overhanging device are connected by a wired transmission line called a front hall. As an interface between such a centralizing device and an overhanging device, for example, a Common Public Radio Interface (CPRI) is known.

By the way, when examining the specifications of 5G described above, it has been proposed to mount the function of the radiophysical layer (layer 1) previously mounted on the centralized device on the overhanging device (for example, Non-Patent Document 1). .. According to such an implementation, the required transmission band of the front hole can be reduced.

Further, in LTE, for the purpose of battery saving of the user device, when the data transmitted / received by the user device does not exist for a certain period or more, the downlink control channel (PDCCH) transmitted from the radio base station is intermittently used only for a specific period. Intermittent reception (DRX) control for receiving is adopted. In the DRX control, the user device executes intermittent reception based on the DRX control information notified from the radio base station. The radio base station manages the operating state (whether or not it is in Active Time) of the user device that executes intermittent reception. The user equipment in the Active Time monitors the PDCCH and transmits channel state information (CSI) and sounding reference signal (SRS) to the radio base station. User devices that are not in Active Time do not monitor PDCCH and do not send CSI / SRS.

3GPP RWS-150051 (3GPP RAN workshop on 5G), “5G Vision for 2020 and Beyond”, 3GPP, September 2015

As described above, when the function of the wireless physical layer previously implemented in the centralized apparatus is implemented in the overhanging apparatus, there are the following problems. That is, the functions of the upper layer (layer 2, etc.) such as the MAC scheduler are implemented in the centralized device as before. However, the interface between the centralized device and the overhanging device did not have a mechanism for notifying information related to DRX. Therefore, the overhanging device could not grasp the operating state of the user device. For example, even when the user device is not in the Active Time, the overhanging device expects to receive CSI / SRS, decodes noise, interference, etc., and centrally aggregates erroneous judgment results (unnecessary judgment results). There was a problem of notifying the device.

Therefore, the present invention has been made in view of such a situation, and even when the function of the upper layer such as the MAC scheduler and the function of the wireless physical layer are separately implemented, the operating state of the user device. It is an object of the present invention to provide a radio base station and a communication control method capable of realizing appropriate control according to the above.

One aspect of the present invention is a radio base station that includes an overhang device and a centralized device, wherein the overhanging device performs wireless communication with a user device, and the central centralized device does not perform wireless communication with the user device. The central aggregation device includes an operation state notification unit that notifies the overhanging device of operation state information indicating whether or not the user device is in active time, and the overhanging device includes the operation state information. At least one of transmission and reception of a signal between the operation state information acquisition unit and the user device based on the operation state information, or at least one of transmission and reception of a signal between the centralized device and the centralized device. It is provided with a control unit for controlling the above.

According to the present invention, even when the functions of the upper layer such as the MAC scheduler and the functions of the wireless physical layer are separately implemented, a wireless base station capable of realizing appropriate control according to the operating state of the user device can be realized. And communication control methods can be provided.

FIG. 1 is an overall schematic configuration diagram of a wireless communication system. FIG. 2 is an overall block configuration diagram of a wireless communication system. FIG. 3 is a functional block configuration diagram of the central aggregation device of the first embodiment. FIG. 4 is a functional block configuration diagram of the overhanging device of the first embodiment. FIG. 5 is a diagram showing a transition of the operating state of the user device when the timer expires. FIG. 6 is a diagram showing a transition of the operating state of the user device at the time of receiving the DRX MAC CE. FIG. 7 is a diagram showing a transition of the operating state of the user device during the random access procedure. FIG. 8 is a diagram showing a CSI / SRS reception sequence. FIG. 9 is a diagram showing a control sequence during a random access procedure. FIG. 10 is a functional block configuration diagram of the central aggregation device of the second embodiment. FIG. 11 is a functional block configuration diagram of the overhanging device of the second embodiment. FIG. 12 is a diagram showing a sequence in which the overhanging device notifies the central centralizing device of the operating state. FIG. 13 is a diagram showing another sequence in which the overhanging device notifies the central aggregation device of the operating state. FIG. 14 is a diagram illustrating an operating state notified between the overhanging device and the central aggregation device when the user device is performing carrier aggregation. FIG. 15 is a diagram illustrating an operating state notified between the overhanging device and the central aggregation device when the user device is performing carrier aggregation. FIG. 16 is a diagram illustrating an operating state notified between the overhanging device and the central aggregation device when the user device is performing carrier aggregation.

Hereinafter, embodiments will be described with reference to the drawings. The same functions and configurations are designated by the same or similar reference numerals, and the description thereof will be omitted as appropriate.

[First Embodiment]
<System configuration>
FIG. 1 is an overall schematic configuration diagram of the wireless communication system 10 according to the present embodiment. The wireless communication system 10 is a wireless communication system according to LTE and 5G, which is a successor system to LTE. In this embodiment, LTE is appropriately referred to as "4G" from the viewpoint of corresponding to 5G. Further, in the present embodiment, the configuration of the wireless communication system immediately after the introduction of 5G is assumed, and the LTE assisted operation in which 5G complements 4G is realized.

The radio communication system 10 includes a core network 20, a radio base station 100, a radio base station 200, and a user device 300.

The core network 20, also called an Evolved Packet Core (EPC), is composed of a mobility management entity (MME), a serving gateway (S-GW), a PDN gateway (P-GW), and the like.

The radio base station 100 is a radio base station according to 4G, and is also called an eNodeB. The radio base station 100 is connected to a device (node) constituting the core network 20 via an S1-MME or S1-U interface.

The radio base station 200 is a radio base station according to 5G. The radio base station 200 is connected to the radio base station 100 via an X2 interface (here, for convenience, referred to as X2-AP', X2-U'). The wireless base station 200 may be directly connected to the core network 20 and operated independently by 5G.

The user device 300 can execute wireless communication with the wireless base station 100 and the wireless base station 200. The user device 300 may be referred to as a UE, a wireless communication terminal or a mobile station. The radio base station 200 and the user device 300 control radio signals transmitted from a plurality of antenna elements to generate a more directional beam, Massive MIMO, and carrier aggregation using a plurality of component carriers (CC). It can support CA) and dual connectivity (DC) in which component carriers are simultaneously transmitted between a plurality of radio base stations and a user device 300.

FIG. 2 is an overall block configuration diagram of the wireless communication system 10. As shown in FIG. 2, the radio base station 100 is composed of a central centralizing device 110 and an overhanging device 160. Similarly, the radio base station 200 is composed of a centralizing device 210 and an overhanging device 260. The radio base station 100 and the radio base station 200 may include devices other than the central centralizing device and the overhanging device.

The central aggregation device 110 has a radio physical layer (L1), a medium access control layer (MAC), a radio link control layer (RLC), and a packet data convergence protocol layer (PDCP). Further, the central aggregation device 110 has a radio resource control layer (RRC) as an upper layer of the PDCP. The central aggregation device 110 is also referred to as a central unit (CU).

The overhanging device 160 can be extended from the installation location of the central centralizing device 110 and arranged remotely. The overhanging device 160 has a radio unit (RF) such as a PA (Power Amplifier) / LNA (Low Noise Amplifier), a radio transmission / reception module, and a modulation / demodulation module. The overhanging device 160 is also referred to as a radio processing unit (Radio Unit (RU)).

The central centralizing device 110 and the overhanging device 160 are connected by a wired transmission line called a front hall. As an interface between the central centralizing device 110 and the overhanging device 160, for example, a Common Public Radio Interface (CPRI) is used.

The central consolidating device 210 and the overhanging device 260 correspond to the above-mentioned central consolidating device 110 and the overhanging device 160, respectively, but have different layer configurations. Specifically, the central aggregation device 210 has MAC and RLC. The overhanging device 260 has L1 and RF. Hereinafter, the central centralizing device 210 may be referred to as a 5G-CU, and the overhanging device 260 may be referred to as a 5G-RU.

<Configuration of each device>
Next, the configuration of the central aggregation device 210 and the overhanging device 260 according to the present embodiment will be described.

FIG. 3 is a functional block configuration diagram of the central aggregation device 210. The central aggregation device 210 includes an information receiving unit 211, an information transmitting unit 213, an operating state management unit 215, an operating state notification unit 217, a scheduler function unit 219, and an X2 interface (IF) unit 221. Each part of the centralized device 210 is realized by hardware elements such as a processor (including memory), a functional module (externally connected IF, etc.), and a power supply.

The information receiving unit 211 receives the information transmitted from the overhanging device 260. For example, to give a specific example related to the present embodiment, the information receiving unit 211 receives the determination result of CSI / SRS, the random access preamble, and the Scheduling Request (SR) from the overhanging device 260. In addition to the above information, the information receiving unit 211 is information transmitted / received between the wireless base station 200 and the user device 300, which is necessary for MAC and RLC and information transmitted to the wireless base station 100. Also receives from the overhanging device 260.

The information transmission unit 213 transmits information to the overhanging device 260. For example, to give a specific example related to the present embodiment, the information transmission unit 213 projects information regarding the operating state (whether or not Active Time is in progress) of the user device 300, the DRX command MAC Control Element (CE). Send to device 260. The information transmission unit 213 transmits not only the above information but also the information transmitted to the user device 300 via the extension device 260 to the extension device 260.

The operation state management unit 215 manages the operation state (whether or not the active time is in progress) of the user device 300 based on the transmission / reception status of the signal to and from the user device 300 based on the specified conditions for the active time. do. Hereinafter, the state in which the user device 300 is in the Active Time is referred to as an active state, and the state in which the user device 300 is not in the Active Time is referred to as an inactive state. The details of the operation state management of the user apparatus 300 by the operation state management unit 215 will be described later.

The operation state notification unit 217 notifies the overhanging device 260 of information regarding the operation state of the user device 300 managed by the operation state management unit 215 via the information transmission unit 213. The details of the operation status notification by the operation status notification unit 217 will be described later.

The scheduler function unit 219 executes scheduling (allocation) of wireless resources to the user device 300 according to the status of a plurality of user devices 300 connected to the wireless base station 200, requests from each of the user devices 300, and the like. do. The scheduler function unit 219 executes scheduling based on the operation state of the user device 300 managed by the operation state management unit 215. The active user device 300 monitors the PDCCH and transmits CSI / SRS. The inactive user device 300 does not monitor the PDCCH and does not transmit CSI / SRS. Therefore, for example, the scheduler function unit 219 executes scheduling so as not to transmit downlink data to the inactive user apparatus 300.

The X2 interface unit 221 provides an interface for realizing communication with the central aggregation device 110. Specifically, the X2 interface unit 221 is an interface that directly connects the central aggregation device 110 and the central aggregation device 210 by using MAC and RLC, and is preferably an existing open interface. The transmission / reception data of the user device 300 is relayed to the radio base station 100 via the X2 interface unit 221.

FIG. 4 is a functional block configuration diagram of the overhanging device 260. The overhanging device 260 includes a wireless communication unit 261, an information transmission unit 263, an information reception unit 265, an operation state acquisition unit 267, and a transmission / reception control unit 269. Each part of the overhanging device 260 is realized by hardware elements such as a duplexer (DUX), a PA / LNA, a radio transmission / reception module (RF conversion), a functional module (orthogonal modulation / demodulation, etc.), and a power supply.

The wireless communication unit 261 executes wireless communication with the user device 300. Specifically, the wireless communication unit 261 executes wireless communication with the user device 300 according to the specifications of 5G. As described above, the wireless communication unit 261 can support Massive MIMO, CA, DC, and the like.

The information transmission unit 263 transmits information to the central aggregation device 210. For example, to give a specific example related to the present embodiment, the information transmission unit 263 transmits the determination result of CSI / SRS, the random access preamble, and the Scheduling Request (SR) to the central aggregation device 210. The information transmission unit 263 is not only the above information but also information transmitted / received between the radio base station 200 and the user device 300, which is necessary for the MAC and RLC of the central aggregation device 210 and the radio base station 100. The information transmitted to is also transmitted to the central aggregation device 210.

The information receiving unit 265 receives the information transmitted from the central aggregation device 210. For example, to give a specific example related to the present embodiment, the information receiving unit 265 receives information regarding the operating state (whether or not Active Time is in progress) of the user device 300, the DRX command MAC CE from the central aggregation device 210. do. The information receiving unit 265 receives not only the above information but also the information transmitted to the user device 300 via the overhanging device 260 from the central aggregation device 210.

The operation state acquisition unit 267 acquires the information regarding the operation state indicating whether or not the user device 300 is in the Active Time from the information received from the central aggregation device 210, and obtains the operation state of the user device 300.

The transmission / reception control unit 269 controls transmission / reception of information to / from the user equipment 300 and transmission / reception of information to the central aggregation device 210 based on the operating state of the user equipment 300. Specifically, the transmission / reception control unit 269 executes CSI / SRS reception control, random access procedure-related control, and error case handling based on the operating state of the user device 300. The details of the control by the transmission / reception control unit 269 will be described later.

<Operation status management process>
Next, the operation state management process of the user apparatus 300 by the central aggregation apparatus 210 will be described.

In the DRX control, it is managed whether or not the user device 300 in the RRC connected state (RRC Connected) is in the Active Time. Specifically, when any of the following conditions is satisfied, the user apparatus 300 is in the Active Time. If none of the following conditions are met, the user device 300 is not in the Active Time.

-When any of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, or mac-ContentionResolutionTimer is running-When Scheduling Request is sent-When UL HARQ retransmission is assigned-UL Grant is assigned. After that, if the PDCCH instructing new transmission has not been received.

The operation state management unit 215 determines whether or not any of the above conditions is satisfied based on the transmission / reception status to the user device 300, and manages the operation state of the user device 300. Hereinafter, some examples of transitions of the operating state of the user apparatus 300 and some operations of the operating state management unit 215 will be described with reference to the drawings.

FIG. 5 is a diagram showing an example in which the user apparatus 300 transitions between an active state and an inactive state according to a timer. When the user device 300 receives the PDCCH from the radio base station 200, the drx-InactivityTimer is started / restarted. While the drx-InactivityTimer is running, the user device 300 is in the active state. When the drx-InactivityTimer expires, the user device 300 becomes inactive. After that, the user apparatus 300 starts the operation for each DRX cycle. In the DRX cycle, the user apparatus 300 becomes active over a predetermined On Duration and remains inactive until the next DRX cycle. The user device activated by OnDuration monitors the PDCCH, transmits CSI / SRS to the radio base station, and the like.

Further, when the user apparatus 300 receives new downlink data during OnDuration, the drx-Inactivity Timer is started / restarted, and the HARQ RTT Timer is started. If the downlink data cannot be decoded correctly, the user device 300 activates the drx-Retransmission Timer when the HARQ RTT Timer expires.

The operation state management unit 215 sets the drx-InactivityTimer at the timing when the overhanging device 260 transmits the newly assigned PDCCH to the user device 300 or at the timing when the overhanging device 260 receives the corresponding ACK / NACK from the user device 300. Start / restart and manage the operating status as the active status. The operation state management unit 215 manages the operation state as an inactive state at the timing when the drx-InactivityTimer expires.

Further, in the operation of the DRX cycle, the operation state management unit 215 manages the operation state as an active state during On Duration, and manages the operation state as an inactive state from after On Duration to the next DRX period. The operation state management unit 215 manages the operation state during the DRX cycle by using the information required for the DRX control notified to the user apparatus 300. Information required for DRX control includes, for example, DRX control information such as onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, and DRX cycle and HARQ RTT. The DRX control information is set by drx-Config notified from the radio base station 200 to the user device 300 via the RRC.

FIG. 6 is a diagram showing another example in which the user apparatus 300 transitions between the active state and the inactive state according to a timer. In FIG. 6, the user device 300 receives the DRX command MAC CE from the radio base station 200 while the drx-InactivityTimer is running. When the user device 300 receives the DRX command MAC CE, the user device 300 forcibly stops the drx-InactivityTimer and becomes inactive. After that, the user apparatus 300 executes the DRX control and starts the operation for each DRX cycle. The operation for each DRX cycle is the same as that described with reference to FIG.

The operation state management unit 215 manages the operation state as an inactive state at the timing when the overhanging device 260 transmits the DRX command MAC CE to the user device 300.

FIG. 7 is a diagram showing an example in which the user apparatus 300 transitions between the active state and the inactive state in relation to the random access procedure.

As shown in FIG. 7, during the random access procedure, the user apparatus 300 provides a random access response (RAR) window after transmitting the random access preamble, and expects to receive the random access response transmitted by the radio base station 200. do. Further, the user apparatus 300 activates the Content Resolution Timer after transmitting the Msg 3 (Scheduled Transition), and expects the reception of the Msg 4 (Contention Resolution) transmitted by the radio base station 200. It is stipulated that it is regarded as an Active Time while the RAR window and Content Resolution Timer are running.

The operation state management unit 215 manages the operation state as an active state during the RAR window period after the overhanging device 260 receives the random access preamble from the user device 300.

Further, the operation state management unit 215 manages the operation state as an active state while the content resolution timer is running after the radio base station 200 receives Msg3 from the user device 300.

Other than those shown in the figure, for example, when the overhanging device 260 receives SR from the user device 300, the operating state management unit 215 manages the operating state as an active state.

<Notification processing of operating status>
Next, the notification processing of the operating state of the user device 300 from the central aggregation device 210 to the overhanging device 260 will be described.

When the operation state of the user device 300 managed by the operation state management unit 215 transitions, the operation state notification unit 217 notifies the extension device 260 of the operation state after the transition. When the operation state changes, the operation state notification unit 217 may trigger an event to notify the extension device 260 of the operation state, or may operate periodically (for example, for each TTI) in addition to the event trigger. The status may be notified to the overhanging device 260.

The operation state notification unit 217 may notify the overhanging device 260 of 1-bit information indicating the operation state (for example, 1 indicates an active state and 0 indicates an inactive state). Alternatively, even if the initial state is defined as one of the states (active state or inactive state) and the operation state notification unit 217 notifies the information indicating the toggle of the operation state (maintenance or change of the operation state). good.

When the operating state notification unit 217 notifies the overhanging device 260 of the operating state, the timing at which the central aggregation device 210 detects the transition of the operating state or the timing at which the overhanging device 260 reflects the operating state. You may notify. The timing may be notified by Hyper System Frame Number (SFN), SFN, and subframe number. By notifying the overhanging device 260 of these timings by the operating state notification unit 217, the overhanging device 260 knows the transition timing of the operating state of the user device 300 more accurately without being affected by the delay in the front hole. be able to.

The operation state notification unit 217 may notify the identifier (C-RNTI, IMSI, IMEI) of the user device 300 when notifying the overhanging device 260 of the operation state.

In this embodiment, it is assumed that the DRX control is executed in units of 300 user devices. When the DRX control is performed in the component carrier unit or the cell group unit, the operation state notification unit 217 may notify the extension device 260 of the operation state for each component carrier or cell group. In this case, the operating state notification unit 217 may notify the identifier of the component carrier or the cell group when notifying the overhanging device 260 of the operating state.

<Control processing>
Subsequently, the control process by the overhanging device 260 will be described.

The overhanging device 260 controls transmission / reception of a signal with the user device 300 and transmission / reception of a signal with the central aggregation device 210 based on the operating state of the user device 300 notified from the central aggregation device 210. Specifically, the transmission / reception control unit 269 performs CSI / SRS reception control, random access preamble reception control during a random access procedure, and error case handling. Hereinafter, each control will be described.

First, CSI / SRS reception control will be described.

The central aggregation device 210 performs scheduling according to the channel state of the downlink. The user device 300 periodically transmits downlink channel state information (CSI) to the overhanging device 260. The CSI consists of one or more pieces of information: a channel quality index (CQI), a precoding matrix index (PMI), a rank index (RI), and a precoding type index (PTI). The overhanging device 260 receives the CSI from the user device 300 and notifies the central aggregation device 210 of the determination result.

Further, the user apparatus 300 periodically transmits a sounding reference signal (SRS) on the uplink in order to enable the radio base station 200 to estimate the channel state of the uplink. The overhanging device 260 receives the SRS from the user device 300 and notifies the central aggregation device 210 of the determination result.

The CSI / SRS determination result transmitted by the overhanging device 260 to the central aggregation device 210 is quality information indicating the radio quality between the overhanging device 260 and the user device 300. The overhanging device 260 periodically notifies the central aggregation device 210 of the determination result of CSI / SRS.

The user device 300 periodically transmits CSI / SRS when it is in the active state, but does not transmit CSI / SRS when it is in the inactive state. Therefore, the transmission / reception control unit 269 controls the reception of CSI / SRS and the notification of the determination result of CSI / SRS according to the operating state of the user device 300.

FIG. 8 is a diagram showing a CSI / SRS reception sequence in consideration of the operating state of the user apparatus 300.

Since the user device 300 is in the inactive state, the CSI / SRS is not transmitted even at the timing of transmitting the CSI / SRS (step S11).

Since the overhanging device 260 is notified by the central aggregation device 210 that the user device 300 is in an inactive state, the CSI / SRS is not received even at the timing of receiving the CSI / SRS, and the determination result is obtained. Is not notified to the central aggregation device 210 (step S12). Alternatively, the overhanging device 260 receives the CSI / SRS, but since it is considered that the received CSI / SRS is a decoding of noise and the like, the determination result of the CSI / SRS is not notified to the central aggregation device 210. You may. Alternatively, the overhanging device 260 may notify the central aggregation device 210 of an "invalid value" or "reception not possible".

When the operating state of the user device 300 managed by the central aggregation device 210 transitions to the active state, the central aggregation device 210 notifies the overhanging device 260 that the user device 300 has become the active state (step S13). From the viewpoint of controlling the CSI / SRS reception timing, the central aggregation device 210 may notify the overhanging device 260 of "CSI / SRS reception start".

When it is time to transmit the CSI / SRS, the user apparatus 300 transmits the CSI / SRS (step S14). The overhanging device 260 receives the CSI / SRS and notifies the central aggregation device 210 of the determination result (step S15).

When the operating state of the user device 300 managed by the central aggregation device 210 transitions to the inactive state, the central aggregation device 210 notifies the overhanging device 260 that the user device 300 has become the inactive state (step S16). .. The central aggregation device 210 may notify the overhanging device 260 of "CSI / SRS reception stop".

Even at the timing of transmitting CSI / SRS, the user apparatus 300 is in an inactive state, so that CSI / SRS is not transmitted (step S17). Since the overhanging device 260 is notified that the user device 300 is in the inactive state, it does not receive the CSI / SRS and does not notify the determination result to the central aggregation device (step S18).

When the operating state of the user device 300 becomes the active state, the central aggregation device 210 notifies the overhanging device 260 of the operating state of the user device 300 (step S19). The user device 300 transmits CSI / SRS at a predetermined timing (step S20). The overhanging device 260 receives the CSI / SRS and notifies the central aggregation device 210 of the determination result (step S21).

When the operating state of the user device 300 becomes inactive, the central aggregation device 210 notifies the overhanging device 260 of the operating state of the user device 300 (step S22). The user device 300 does not transmit CSI / SRS (step S23). The overhanging device 260 does not receive the CSI / SRS and does not notify the central aggregation device 210 of the determination result (step S24).

When notifying the overhanging device 260 from the central aggregation device 210, other setting information and states such as the presence / absence of the cqi-mask setting, the measurement gap timing, and the activation state of the SCell (secondary cell) are taken into consideration. May be done. When cqi-mask or Measurement gap is set, the user device 300 may not transmit CSI / SRS even if it is in the active state. At this time, the central aggregation device 210 may notify the overhanging device 260 of the "inactive state (CSI / SRS reception not required)".

As described above, when the overhanging device 260 receives the operating state indicating that the user device 300 is in the inactive state from the central aggregation device 210, the overhanging device 260 suppresses the transmission of the CSI / SRS determination result to the central aggregation device 210. do. As a result, when the user device 300 is in the inactive state, the overhanging device 260 does not transmit an erroneous determination result obtained by decoding noise, interference, or the like to the central aggregation device 210, and the overhanging device 260 does not transmit an erroneous determination result on the front hall. It is possible to avoid the transmission of unnecessary signals.

Although the CSI / SRS reception control has been described above, the present embodiment can be applied not only to the CSI / SRS but also to any signal whose transmission / reception necessity is determined by the active state.

Next, the reception control of the random access preamble during the random access procedure will be described.

FIG. 9 is a diagram showing a control sequence during a contention-free method (non-competitive) random access procedure. Random access procedures are used for initial access, reconnection, handover, or DL / UL data reservation when uplink synchronization is not established.

In the contention-free random access procedure, the radio base station 200 assigns and transmits a contention-free random access preamble to the user device 300 (step S31).

The user apparatus 300 transmits a contention-free random access preamble to the radio base station 200 (step S32).

When the central aggregation device 210 receives the contention-free random access preamble from the user device 300, the central aggregation device 210 manages that the user device 300 is in the active state, and determines that the user device 300 is in the active state with respect to the overhanging device 260. Notify (step S33). The RAR window of the user device 300 is started 3 subframes after the transmission timing of the random access preamble. During the RAR window period, the user device 300 is in the active state.

When the extension device 260 receives the contention-free random access preamble from the user device 300 and then receives the notification of the active state from the central aggregation device 210 (step S34), the overhanging device 260 receives the random access preamble from the user device 300. Discontinue.

At the end of the RAR window period, the central aggregation device 210 notifies the overhanging device 260 that the user device 300 is inactive (step S35). During the RAR window, when the radio base station 200 transmits RAR to the user device 300, the central aggregation device 210 notifies the overhanging device 260 that the user device 300 is in an inactive state. May be good.

If the RAR cannot be received in the RAR window, the user device 300 attempts to retransmit the random access preamble after the RAR window ends. The overhanging device 260 starts receiving the random access preamble.

As described above, when the extension device 260 receives the notification of the active state from the central aggregation device 210 after receiving the contention-free random access preamble, the overhanging device 260 suppresses the reception of the random access preamble, thereby performing unnecessary random access. False detection of preamble can be avoided.

It should be noted that the above process can also be applied to a contention-based random access procedure.

Next, error case handling will be described.

When the central aggregation device 210 notifies that the user device 300 is inactive, the extension device 260 is instructed to transmit PDCCH to the user device 300 by the central aggregation device 210. The 260 may consider it as an error case and notify the central aggregation device 210 of the failure (Failure). At this time, the overhanging device 260 does not have to carry out PDCCH transmission.

As described above, when the overhanging device 260 receives the downlink control signal inconsistent with the notified operating state from the central centralizing device 210, the overhanging device 260 notifies the central centralizing device 210 of the file, thereby causing the central centralizing device 210. It can be expected to correct the operating state managed by 210 or to notify the correct operating state.

As described above, according to the present embodiment, the operation state notification unit 217 notifies the extension device 260 of the operation state of the user device 300 managed by the central aggregation device 210, and the transmission / reception control unit 269 is notified. By controlling the transmission / reception of signals to / from the user equipment and the transmission / reception of signals to / from the central aggregation device 210 based on the operating state of the user equipment 300, the overhanging device 260 may transmit / receive erroneous information. It is possible to suppress the transmission and reception of unnecessary information. That is, even when the function of the upper layer such as the MAC scheduler and the function of the wireless physical layer are separately implemented, appropriate control can be realized according to the operating state of the user device.

According to the present embodiment, when the overhanging device 260 receives an operating state indicating that the user device 300 is in an inactive state from the central centralizing device 210, the overhanging device 260 transmits a CSI / SRS determination result to the central centralizing device 210. Suppress. As a result, the overhanging device 260 does not transmit an erroneous determination result obtained by decoding noise, interference, or the like to the central aggregation device 210, and can avoid transmitting unnecessary signals on the front hall.

According to the present embodiment, when the extension device 260 receives the notification of the active state from the central aggregation device 210 after receiving the contention-free random access preamble, the extension device 260 suppresses the reception of the random access preamble. This makes it possible to avoid false detection of unnecessary random access preambles.

According to the present embodiment, when the overhanging device 260 receives a downlink control signal inconsistent with the notified operating state from the central centralizing device 210, the overhanging device 260 notifies the central centralizing device 210 of the file. As a result, it can be expected to correct the operating state managed by the central aggregation device 210 or to notify the correct operating state.

[Second Embodiment]
Next, the second embodiment will be described. In the first embodiment, the central aggregation device 210 manages the operating state of the user device 300, but in the second embodiment, the overhanging device 260 manages the operating state of the user device 300, and the operating state thereof. Is notified to the central aggregation device 210. Hereinafter, the parts different from the first embodiment will be mainly described, and the parts similar to the first embodiment will be omitted as appropriate.

<Configuration of each device>
FIG. 10 is a functional block configuration diagram of the central aggregation device 210 according to the second embodiment. Compared with the central aggregation device according to the first embodiment, the central aggregation device 210 according to the second embodiment does not include the operation state management unit 215 and the operation state notification unit 217, and has the DRX setting notification unit 223 and the operation state. The difference is that the acquisition unit 225 is provided.

When the radio base station 200 sets the DRX control information to the user device 300 via the RRC, the DRX setting notification unit 223 notifies the extension device 260 of the information necessary for the DRX control.

The operation state acquisition unit 225 acquires the information regarding the operation state indicating whether or not the user device 300 is in the Active Time from the information received from the overhanging device 260, and obtains the operation state of the user device 300. The scheduler function unit 219 performs scheduling based on the operating state of the user device 300 acquired from the overhanging device 260.

FIG. 11 is a functional block configuration diagram of the overhanging device 260 according to the second embodiment. Compared with the extension device according to the first embodiment, the extension device 260 according to the second embodiment does not include the operation state acquisition unit 267, but includes the operation state management unit 271 and the operation state notification unit 273. Is different.

The operation state management unit 271 manages the operation state of the user device 300 based on the transmission / reception status of the signal with the user device 300 based on the condition of the defined Active Time. The operation state management unit 271 manages the operation state of the user device 300 by using the information required for DRX control notified from the central aggregation device 210.

The operation state notification unit 273 notifies the central aggregation device 210 of information regarding the operation state of the user device 300 managed by the operation state management unit 271 via the information transmission unit 263. The details of the operation status notification by the operation status notification unit 273 will be described later.

<Operation of overhanging device>
In the second embodiment, the overhanging device 260 manages the operating state of the user device 300. The operation state management process executed by the overhanging device 260 is the same as the management process executed by the central aggregation device 210 of the first embodiment. Further, the process of controlling the transmission / reception of the signal with the user device 300 and the transmission / reception of the signal with the central aggregation device 210 based on the operating state of the overhanging device 260 is the same as that of the first embodiment. be.

<Notification processing of operating status>
The process in which the overhanging device 260 notifies the central aggregation device 210 of the operating state of the user device 300 will be described.

FIG. 12 is a diagram showing a sequence in which the overhanging device 260 notifies the central aggregation device 210 of the operating state of the user device 300. Condition 1, condition 2, and condition 3 shown in the figure are conditions in which the user device 300 becomes an Active Time. For example, condition 1 is that drx-InactivityTimer is running, condition 2 is SR received, and condition 3 is that onDurationTimer is running. If any one of the conditions is True, the user device 300 is in the active state. That is, when all the conditions are False, the user device 300 is inactive. In the figure, only three conditions are shown for simplicity. The conditions are not limited to this, and other conditions may be added.

At the first time point in FIG. 12, since the condition 1 is True, the operating state of the user apparatus 300 is the active state. The operation state management unit 271 manages the operation state as an active state.

Even if condition 2 becomes True, the operating state does not change in the active state because Condition 1 was True even before that. After that, even if the condition 1 becomes False, the operating state does not change in the active state because the condition 2 is True.

When condition 2 becomes False, condition 1 and condition 3 become False before that, and all the conditions become False at this timing, so that the operating state transitions to the inactive state. Since the operating state transitions from the active state to the inactive state, the overhanging device 260 notifies the central aggregation device 210 that the operating state has changed from the active state to the inactive state (step S51). When the central aggregation device 210 is notified of the operating state, the central aggregation device 210 performs scheduling in consideration of the new operating state.

After that, when the operating state changes, the overhanging device 260 notifies the central aggregation device 210 that the operating state has changed (steps S52 to S55).

FIG. 13 is a diagram showing another sequence in which the overhanging device 260 notifies the central aggregation device 210 of the operating state of the user device 300. In the example of FIG. 12, the overhanging device 260 notifies the central aggregation device 210 of the transition of the operating state at the timing when the operating state of the user device 300 changes. In the example of FIG. 13, the overhanging device 260 notifies the central aggregation device 210 for each condition for determining the operating state of the user device 300.

When the condition 2 becomes True, the operating state does not change because the condition 1 was True even before that, but the overhanging device 260 notifies the central aggregation device 210 that the condition 2 has changed. (Step S61).

After that, even if the condition 1 becomes False, the operating state does not change in the active state because the condition 2 is True, but the overhanging device 260 notifies the central aggregation device 210 that the condition 1 has changed (the condition 1 has changed). Step S62).

When condition 2 becomes False, condition 1 and condition 3 become False before that, and all the conditions become False at this timing, so that the operating state transitions to the inactive state. The overhanging device 260 notifies the central aggregation device 210 that the condition 2 has changed (step S51). At this time, it may be notified that the operating state has changed to the inactive state.

After that, when the conditions change, the overhanging device 260 notifies the central aggregation device 210 that the conditions have changed (steps S52 to S55).

As a modification of the above example, when the overhanging device 260 notifies the central aggregation device 210 of a change in an operating state or a condition, it may be clearly stated that the notification is for an uplink, a downlink, or both. good. Specifically, when the radio base station 200 receives the SR from the user device 300, it can be seen that the user device 300 expects the allocation of the uplink radio resource, so that the overhanging device 260 is the centralized device 210. For example, "Active Time for UL" may be notified by clearly indicating that it is related to the uplink. Alternatively, since it can be seen that the user device 300 is expecting the allocation of the downlink radio resource while the drx-RetransmissionTimer is running, the overhanging device 260 clearly indicates to the central aggregation device 210, for example, the downlink. Then, "Active Time for DL" may be notified. Further, for the drx-Inactivity Timer and On Duration, the overhanging device 260 may notify the central aggregation device 210 of "Active Time for ANY" by clearly indicating, for example, that it is related to the uplink and the downlink.

As in the first embodiment, the operation state notification unit 273 notifies the central aggregation device 210 of the event occurrence timing and the identifier of the user device 300 when notifying the change of the operation state or the condition. May be good.

<When carrier aggregation is applied>
When the user device 300 uses carrier aggregation that communicates using the component carriers of the plurality of extension devices 260A and 260B, when the extension devices 260A and 260B manage the operating state, they are shown in FIGS. 14 to 16. The form is conceivable.

In the example shown in FIG. 14, each of the plurality of overhanging devices 260A and 260B independently manages the operating state of the user device 300, and the central centralizing device 210 is notified by each of the plurality of overhanging devices 260A and 260B. Scheduling of the user apparatus 300 is performed using the operating state. For example, the central aggregation device 210 determines the operating state of the user device 300 by taking the logical sum of the operating states notified from each of the plurality of overhanging devices 260A and 260B, and schedules the user device 300.

In the example shown in FIG. 15, each of the plurality of overhanging devices 260A and 260B independently manages the operating state of the user device 300, and the central centralizing device 210 is notified by each of the plurality of overhanging devices 260A and 260B. Notify the other overhanging devices 260A and 260B of the operating state. Each of the overhanging devices 260A and 260B updates the operating state managed by itself based on the operating state managed by the other overhanging devices 260A and 260B notified via the central aggregation device 210. Specifically, for example, in the overhanging device 260A, when the drx-InactivityTimer is started / restarted, the overhanging device 260A has started / restarted the drx-InactivityTimer with respect to the central aggregation device 210. The central aggregation device 210 notifies the other overhanging device 260B that the drx-InactivityTimer has been started / restarted. The overhanging device 260B executes the start / restart of the drx-InactivityTimer with the notification. The overhanging device 260A may notify the central aggregation device 210 of the event occurrence timing, and the central aggregation device 210 may notify the overhanging device 260B of the event occurrence timing. By notifying the event occurrence timing by the overhanging device 260A, it is possible to process the management of the operating state in consideration of the delay between the central summarizing device 210 and the overhanging devices 260A and 260B.

Further, the central aggregation device 210 may notify the overhanging device 260B of only a part of the event notified from the overhanging device 260A. For example, at the time of SR reception, the user device 300 may be notified only to the overhanging device 260 in which UL CC / Cell is set. Further, the central centralizing device 210 does not have to notify the other overhanging device 260B of the control closed in the CC, such as the drx-RetransmissionTimer.

In the embodiment of FIG. 15, the central aggregation device 210 has a function of notifying another overhanging device 260B of the operating state notified from the overhanging device 260A. The overhanging devices 260A and 260B have a function of acquiring an operating state notified from the central aggregation device 210 and a function of updating the operating state managed by the overhanging device 260A and 260B.

In the example shown in FIG. 16, those managed by the user device 300 are managed by the central centralizing device 210, and those managed by being closed in the CC are controlled by the overhanging devices 260A and 260B. to manage. Examples of devices managed in units of 300 user devices include drx-InactivityTimer and onDurationTimer. For example, there is a drx-RetrancemissionTimer that is closed and managed in the CC. The operating state managed by the central aggregation device 210 is notified to each of the overhanging devices 260A and 260B. The overhanging devices 260A and 260B update the operating state managed by themselves based on the operating state notified from the central aggregation device 210.

In the embodiment of FIG. 16, the central aggregation device 210 has a function of managing a part of the operating state of the user device 300 and a function of notifying the operating state to the extension devices 260A and 260B. The overhanging devices 260A and 260B have a function of managing a part of the operating state, a function of acquiring the operating state notified from the central aggregation device 210, and a function of updating the operating state managed by the overhanging device 260A and 260B.

The CC under the overhanging devices 260A and 260B is in the activated state for the management of the operating state in the overhanging devices 260A and 260B and the information exchange between the centralizing device 210 and the overhanging devices 260A and 260B described here. It may be carried out only in the case of.

Further, when the user device 300 receives the DRX command MAC CE, the user device 300 forcibly shifts to the inactive state. If the DRX command MAC CE exceeds the HARQ retransmission, it is considered that the user device 300 has transitioned to the inactive state, and the central aggregation device 210 forcibly forces each of the overhanging devices 260A and 260B. You may instruct the transition to the inactive state.

When the DRX control is performed in CC units or cell group units, the central aggregation device 210 may notify only the overhanging devices 260A and 260B responsible for the related CC / Cell.

As described above, according to the present embodiment, the overhanging device 260 includes an operation state management unit 271 that manages the operation state of the user device 300, and the transmission / reception control unit 269 is based on the operation state of the user device 300. By controlling the transmission / reception of the signal to / from the user device and the transmission / reception of the signal to / from the central aggregation device 210, the overhanging device 260 can suppress the transmission / reception of erroneous information and the transmission / reception of unnecessary information. That is, even when the function of the upper layer such as the MAC scheduler and the function of the wireless physical layer are separately implemented, appropriate control can be realized according to the operating state of the user device.

The present invention may be expressed as follows. One aspect of the present invention includes a overhanging device (overhanging device 260) and a central consolidating device (central consolidating device 210), and a radio base station (radio base station) that executes wireless communication with the user device (user device 300). 200) The central aggregation device includes an operation state notification unit (operation state notification unit 217) that notifies the overhanging device of operation state information indicating whether or not the user device is in active time. The overhanging device is at least transmitting and receiving a signal between the operating state information acquisition unit (operating state acquisition unit 267) that receives the operating state information and the user device based on the operating state information. It includes a control unit (transmission / reception control unit 269) that controls at least one of transmission and reception of a signal to and / or the central aggregation device.

In one aspect of the present invention, when the control unit receives the operating state information indicating that the user device is not in active time, the quality information indicating the radio quality between the user device and the centralized device is indicated. You may suppress the transmission of.

In one aspect of the present invention, when the control unit receives the random access preamble from the user device and then receives the operation state information indicating that the user device is in active time from the central aggregation device. The reception of the random access preamble from the user device may be suppressed.

In one aspect of the present invention, when the control unit receives the downlink control signal for the user device from the central aggregation device after receiving the operation state information indicating that the user device is not in the active time. An error may be notified to the central aggregation device.

One aspect of the present invention is a communication control method in a radio base station that includes an overhang device and a centralized device and executes wireless communication with the user device, wherein the centralized device is in active time of the user device. A signal between the step of notifying the overhanging device of the operating state information indicating whether or not the device is, and the user device based on the operating state information received from the centralized device by the overhanging device. Includes a step of controlling at least one of transmission and reception of and / or at least one of transmission and reception of a signal to and from the centralized device.

One aspect of the present invention includes a overhanging device (overhanging device 260) and a central consolidating device (central consolidating device 210), and a radio base station (radio base station) that executes wireless communication with the user device (user device 300). 200) The central aggregation device includes an operation state receiving unit (operating state state acquisition unit 267) for receiving operation state information indicating whether or not the user device is in active time, and the overhanging device. The device centrally aggregates the operation state management unit (operation state management unit 271) that manages the operation state information of the user device and the operation state information based on the signal transmission / reception status with the user device. Between the operation status notification unit (operation status notification unit 273) that notifies the device and at least one of transmission and reception of a signal between the user device and / or the central aggregation device based on the operation status information. A control unit (transmission / reception control unit 269) that controls at least one of transmission and reception of the signal of the above is provided.

One aspect of the present invention is a communication control method in a radio base station that includes an overhang device and a centralized device and executes wireless communication with the user device, wherein the centralized device is in active time of the user device. A step of receiving the operation state information indicating whether or not the user device is, and a step of managing the operation state information of the user device based on the transmission / reception status of the signal between the overhanging device and the user device. The step of notifying the centralized device of the operating state information by the overhanging device, and at least transmission and reception of a signal between the overhanging device and the user device based on the operating state information. It comprises a step of controlling at least one of transmission and reception of a signal to and / or the centralized device.

10 ... Wireless communication system 100 ... Wireless base station 110 ... Central centralization device 160 ... Overhanging device 20 ... Core network 200 ... Wireless base station 210 ... Central centralization device 211 ... Information receiving unit 213 ... Information transmission unit 215 ... Operation status management unit 217 ... Operating status notification unit 219 ... Scheduler function unit 221 ... X2 interface unit 223 ... DRX setting notification unit 225 ... Operating status acquisition unit 260, 260A, 260B ... Overhanging device 261 ... Wireless communication unit 263 ... Information transmission unit 265 ... Information Reception unit 267 ... Operation status acquisition unit 269 ... Transmission / reception control unit 271 ... Operation status management unit 273 ... Operation status notification unit 300 ... User device

Claims (5)

A radio base station that includes an overhang device and a centralized device, wherein the overhanging device performs wireless communication with a user device, and the central centralized device does not perform wireless communication with the user device.
The central aggregation device is
It is provided with an operation state notification unit for notifying the overhanging device of operation state information indicating whether or not the user device is in active time.
The overhanging device is
The operation state information acquisition unit that receives the operation state information, and
A control unit that controls at least one of transmission and reception of a signal to and from the user device or at least one of transmission and reception of a signal to and from the central aggregation device based on the operation state information.
A wireless base station equipped with. A claim that the control unit suppresses transmission of quality information indicating radio quality to and from the user device to the central aggregation device when the operation state information indicating that the user device is not in active time is received. The radio base station according to 1. When the control unit receives the operation state information indicating that the user device is in the active time from the central aggregation device after receiving the random access preamble from the user device, the control unit receives the random access preamble from the user device. The radio base station according to claim 1, which suppresses reception of an access preamble. When the control unit receives the downlink control signal for the user device from the central aggregation device after receiving the operation state information indicating that the user device is not in the active time, the control unit receives the downlink control signal for the user device with respect to the central aggregation device. The radio base station according to claim 1, which notifies an error. A communication control method in a radio base station including an overhanging device and a central centralizing device, wherein the overhanging device performs wireless communication with a user device, and the central centralizing device does not perform wireless communication with the user device.
A step in which the central centralizing device notifies the overhanging device of operating state information indicating whether or not the user device is in active time.
The overhanging device transmits and receives at least one of transmission and reception of a signal to and from the user device or a signal transmission and reception to and from the central aggregation device based on the operation state information received from the central aggregation device. And the steps to control at least one of
Communication control method including.

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