KR101749537B1 - method for operating base station in mobile telecommunication system - Google Patents

Abstract

The present invention is applied to a base station of a 5G mobile communication system in which a base station is divided into a plurality of beam spots by using a millimeter wave, thereby reducing the power of a transmission / reception module of a modem corresponding to each beam spot, To a base station operating method of a mobile communication system.

Description

TECHNICAL FIELD The present invention relates to a method for operating a base station in a mobile communication system,

The present invention relates to a base station operating method in a mobile communication system, and more particularly to a base station of a 5G mobile communication system in which a base station is divided into a plurality of beam spots by using millimeter waves, To a base station operating method of a mobile communication system.

The International Telecommunication Union-Radiocommunication Sector (ITU-R) is currently developing a vision for various convergence services based on 5G networks. The government also established a strategy for developing future mobile communication industry in January 2014, Future SNS, Mobile Stereoscopic Image, Intelligent Service, High Speed Service and UHD / Hologram.

In addition, the European Union, China, Japan, and Korea have set up a dedicated organization to discuss 5G networks and services. In addition to innovations in mobile communication technologies that provide users with gigabit-class high-speed transmission, We are discussing user-oriented 5G service that reflects the life-style.

5G is expected to have requirements from approximately five perspectives, although international requirements and technical specifications have not yet been finalized.

- Ultra High Speed & Low Latency: 1000 times faster than LTE and ultra low latency response within tens of ms, realistic contents.

- Massive / Seamless Connectivity: 1000 times more devices and traffic, ensuring seamless connectivity.

- Intelligent / Flexible Network: Provides software infrastructure, real-time data analysis, intelligent / personalized services.

- Reliable / Secure Operation: More than 99% network continuity / reliability, Self-Healing / Reconfiguration.

Energy / Cost-Efficient Infra: 50 ~ 100 times energy efficiency compared to LTE, infrastructure / equipment cost reduction.

On the other hand, in the 5G mobile communication, the use of a frequency band corresponding to a millimeter wave (mmWave) frequency band, for example, 10 GHz to 300 GHz, in which continuous optical bandwidths of at least 500 MHz are easily secured for large- have. In this millimeter-wave frequency band, the electromagnetic waves are focused on a narrow beam by concentrating the energy of the antenna because of large free space loss, large loss due to atmospheric and rain attenuation, strong directivity, and large propagation loss due to diffraction and transmission. .

1 is a physical block diagram of a base station of a 5G mobile communication system applicable to the method of the present invention. 1, a mobile communication cell 20 covered by one base station in the 5G mobile communication system includes a plurality of (for example, 16) beam spots arranged in a matrix form Beam Spot), and each of the beam spots can be covered by a plurality of antenna elements 10 corresponding to one-to-one correspondence or one-to-one M (M, multiple). Each antenna element may be implemented as a patch antenna or a horn antenna. In FIG. 1, the antenna array 10 is illustrated in which the antenna elements are arranged in a matrix form, for example, a matrix of 4 * 4.

In the above-described configuration, as described later, since each beam spot is managed in a one-to-one or one-to-many correspondence with the RF transmitting / receiving module of the modem, a single base station is provided with a large number of RF transmitting / receiving modules, There is a need to provide a low-latency seamless service while reducing power consumption by operating the RF transmission / reception module in a sleep mode while the RRC-connected UE is not present.

Patent Document 1: 10-2011-0034774 Patent Document 1: Apparatus and method for reducing power consumption in a multi-antenna system Patent Document 2: 10-2015-0095503 Patent Document title: METHOD AND APPARATUS FOR CONNECTING BEAM STATIONS) Patent Document 3: Prior Art 3: 10-2016-0004003 Patent Document: (Title of the Invention: Handover Method and Apparatus)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a 5G mobile communication system in which a base station is divided into a plurality of beam spots by using millimeter waves, The present invention also provides a method of operating a base station of a mobile communication system,

According to another aspect of the present invention, there is provided a method for operating a base station in a mobile communication system, the method comprising: dividing a base station into a plurality of beam spots arranged in a matrix by a millimeter wave beam emitted from a plurality of antenna elements, The modem is operated by the beam scheduler responsible for beam scheduling in a state where the modem including the transmission / reception module is supported, and when there is no terminal active in any beam spot, the modem of the beam spot is switched to the power saving mode sleep mode (a); (B) obtaining location information of a terminal from each beam spot having an active terminal and determining whether the terminal is located in an edge region of an arbitrary beam spot; (C) determining whether an adjacent beam spot belongs to the same base station or an adjacent base station when the terminal is located in an edge region of an arbitrary beam spot as a result of the determination in the step (b); (D) when the neighboring beam spot belongs to the same base station and the neighboring beam spot is in a sleep mode as a result of the determining in the step (c), the neighboring beam spot is switched to an active mode; And (e) notifying the beam scheduler of the neighboring base station of the position information of the neighbor base station when the adjacent beam spot belongs to the neighbor base station as a result of the determining in the step (c) And periodically activates the transmission module of the mobile station for a predetermined period of time.
In the above-described configuration, the location information of the terminal is the geographical coordinate data transmitted after the terminal detects it in its own GPS receiver.
The MIB (Master Information Block) is transmitted every 40 ms, and the SIB (System Information) is transmitted every 80 ms. The reception module of the modem, which is in the sleep mode, , And waits for reception of a PRACH (Physical Random Access Channel) from the terminal.

According to the base station operating method of the mobile communication system of the present invention, the power of a modem corresponding to each beam spot is reduced by applying the millimeter wave to a base station of a 5G mobile communication system partitioned into a plurality of beam spots, It is possible to provide a continuous service with low delay by operating the modem of the adjacent beam spot in the active mode in advance before moving the terminal based on the provided location information.

1 is a physical configuration diagram of a base station of a 5G mobile communication system applicable to the method of the present invention.
2 is a functional block diagram of a base station of a 5G mobile communication system to which the method of the present invention can be applied;
3 is a flowchart illustrating a method of operating a base station in a mobile communication system according to the present invention.
4 is a timing chart for explaining an activation period of a transmission / reception module of a modem operating in a sleep mode in the method of the present invention.
5 is an exemplary diagram for explaining a case where a terminal is located in an edge area in the method of the present invention;
6 is an exemplary diagram for explaining another edge area setting method in the method of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a base station operating method of a mobile communication system according to the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, a user terminal may be referred to as a user equipment (UE), a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS) A High Reliability Mobile Station (HR-MS), a Subscriber Station (SS), a Portable Subscriber Station (PSS), an Access Terminal (AT) MT, MS, AMS, HR-MS, SS, PSS or AT, and the like.

In addition, a base station (BS) includes a Node B, an evolved Node B (eNB), an Advanced Base Station (ABS), a High Reliability Base Station ), An access point (AP), a radio access station (RAS), a base transceiver station (BTS), and the like. The Node B, the eNB, the BS, the ABS, -BS AP, RAS, or BTS, or the like.

2 is a functional block diagram of a base station of a 5G mobile communication system to which the method of the present invention can be applied. 2, the base station of the 5G mobile communication system to which the method of the present invention can be applied includes a modem 110 corresponding to each of a plurality of beam spots, a MAC (Media Access Control ) Processing unit 120 and a beam scheduler 130 and an upper layer processing unit 140 for controlling the power of each modem 110 by communicating with the respective MAC processing units 120. [

In the above-described configuration, each of the modems 110 includes a transmission (Tx) module and a physical layer (hereinafter, simply referred to as a " TX ") module, each of which includes a beam antenna PHY processing unit '). The reception (Rx) module converts an analog RF signal received through the antenna array 10 into a digital baseband signal and then transmits the baseband signal to the PHY processing unit. The transmission (Tx) Converts the baseband signal of the RF signal into an RF signal of an analog form and then wirelessly transmits the RF signal through the antenna array 10. The PHY processing unit performs general physical layer functions such as channel coding and decoding for data and control signals, digital modulation / demodulation, multi-antenna mapping, and radio resource mapping.

Next, the MAC processing unit 120 performs a general MAC layer function such as mapping between a logical channel and a transport channel, error correction, distribution of time and frequency resources to a plurality of terminals, and the like, Periodically or non-periodically reports information to the beam scheduler 130, and controls the power mode of the modem 110 according to an instruction from the beam scheduler 130. The power mode of the modem 110 can be divided into a sleep mode corresponding to the power saving mode and an active mode corresponding to the normal operation mode. In the active mode, the power is constantly supplied to the RF transmitting and receiving module of the modem 110, Mode, power is supplied to the RF transmit / receive module of the modem only during the period and symbol interval determined by the standard.

The beam scheduler 130 receives information on an active terminal (including a terminal which newly enters an arbitrary beam spot or wakes up in an idle state and newly requests resource allocation) from each MAC processing unit 120, And instructs the terminal 120 to allocate time and frequency resources to these terminals. The beam scheduler 130 receives the positional information of the active terminal from the MAC processor 120 and determines whether the neighbor beam or the neighbor base station is movable, that is, whether the terminal is located in the edge area of the beam spot If the neighbor BS is located in the edge area, the MAC processor 120 instructs the neighbor beam modem 110 to switch to the active mode or transmits the location information of the UE to the beam scheduler 130 of the neighbor base station, Take measures to prepare for handover. For this purpose, the beam schedules 130 of each base station are interconnected.

Next, the upper layer processing unit 140 performs fragmentation and concatenation processing of the packet for transferring the packet size from the upper PDCP layer to the MAC layer size, and transmission of data by transmission error and retransmission management A PDCP layer performing RLC (Radio Link Control) layer for enhancing reliability, performing compression of an IP packet header, ciphering of control messages and user data, data integrity and data loss prevention during handover, (Radio Resource Control) layer that performs functions related to setting, re-establishing and releasing radio bearers between the UE and the RAN, and a Radio Resource Control (RRC) Since the layer processing unit 140 is based on the LTE or LTE-A system, i.e., 3G or 4G, It may be changed.

FIG. 3 is a flowchart illustrating a method of operating a base station in a mobile communication system according to the present invention, and is performed by a beam scheduler 130 as a subject. 3, according to the base station operating method of the mobile communication system of the present invention, the beam scheduler 130 receives an active terminal from the MAC processing unit 120 that manages each beam spot (a new entry into a local beam spot, (including a terminal that wakes up in an idle state and newly requests resource allocation), and instructs each MAC processing unit 120 to allocate time and frequency resources to these terminals.

In this state, the beam scheduler 130 determines whether there is a beam spot without an active terminal (step S10). If it is determined in step S10 that there is a beam spot without an active terminal, the process proceeds to step S20 Thereby switching the operation mode of the controlled modem from the active mode to the sleep mode, that is, the power saving mode. Here, if there is no resource allocation request such that the predetermined time, for example, 10 seconds, elapses from the last resource allocation request time of the terminal, the MAC processing unit 120 determines that the terminal has switched from the active mode to the idle mode (RRC-idle) And transmits the information to the beam scheduler 130.

Next, in step S30, the beam scheduler 130 periodically instructs the modem operating in the sleep mode through the MAC processor 120 so that the transmitter / receiver module is activated only for a short time.

4 is a timing chart for explaining an activation period of a transmission / reception module of a modem operating in a sleep mode in the method of the present invention. As shown in FIG. 4, the beam scheduler 130 of the present invention supports active operation of a terminal that is operating in an idle mode in a beam spot or a new terminal is added to a local beam spot of a modem operating in a sleep mode (MIB), which is one of the cell system information, is activated by activating the transmission module of the corresponding modem only for a predetermined time (symbol) every predetermined period, for example, every 40 ms. (SIB), which is one of the other cell system information, is transmitted. For example, the receiving module of the corresponding modem is activated at a timing determined by the LTE standard on the basis of every 80 ms, and a PRACH Channel). The timing chart of FIG. 4 is described using the LTE standard as an example. Since it can be appropriately changed in 5G, detailed description thereof will be omitted.

  Returning to FIG. 3, in step S40, it is determined whether there is a newly active terminal, that is, a newly added terminal or a terminal that has been active-switched in the idle mode. If yes, the process proceeds to step S50 to switch the modem to the active mode .

On the other hand, if it is determined in step S10 that all the modems of the base station are operating in the active mode, the process proceeds to step S60 to periodically acquire the location information of the terminals existing in the respective beam spots. And may be geographical coordinate data detected and transmitted by the provided GPS receiver.

Next, in step S70, it is determined whether or not there is a terminal located in an edge area of an arbitrary beam spot based on the location information of such terminal. If it is determined in step S70 that there is a terminal located in an edge area of an arbitrary beam spot, step S80 is performed again to determine whether the edge area is adjacent to the adjacent base station.

5 is an exemplary diagram illustrating a case where a terminal is located in an edge region in the method of the present invention. As shown in FIG. 5, when the terminal is located in any beam spot, for example, a beam spot of FIG. 1 to 6, a total of eight adjacent beam spots may exist in the front, rear, left and right and diagonal directions, There can be a total of eight. On the other hand, in the beam scheduler 130, the geographical coordinates of each beam spot, i.e., the geographical coordinates of each vertex of a rectangle and the geographical coordinates of the edge region are stored in advance. When the geographical coordinates according to the current position of the terminal are received, It can be determined which edge area of the serving beam spot exists.

For example, in a case where the terminal is currently positioned in the sixth beam spot and is in service and moved to the edge region S in the south direction, the beam scheduler 130 determines whether the terminal is likely to move to the next 10 beam spots . Similarly, when the terminal moves to the edge area SW in the southwest direction, the beam scheduler 130 determines that the terminal is likely to move to one of the 5th, 9th and 10th beam spots.

On the other hand, when the terminal is located in the edge area E in the east direction of the 4th, 8th, 12th and 16th beam spots in Fig. 1, the terminal is located in the edge area adjacent to the adjacent base station, I think there is a possibility.

If it is determined in step S80 that the edge area where the terminal is located is not the edge area adjacent to the adjacent base station, the process proceeds to step S90 again to determine whether the modem of the adjacent beam spot is operating in the sleep mode. , The flow advances to step S100 to switch the beam spot modem to the active mode. On the other hand, if it is determined in step S80 that the edge region in which the mobile station is located is adjacent to the neighbor base station, the mobile station may move to the neighbor base station. Accordingly, the beam scheduler 130 of the neighbor base station Thereby preparing the possibility of handover.

In this regard, when the beam scheduler 130 receives the position information of the terminal from the beam scheduler of the adjacent base station, it immediately operates the beam spot in the active mode when the modem of the corresponding beam spot operates in the sleep mode.

6 is an exemplary diagram for explaining another edge area setting method in the method of the present invention. According to the edge area setting method shown in FIG. 6, when the terminal is located in the north edge region N of the sixth beam spot, the adjacent beam spots are divided into five, i.e., first, second, third, fifth, It will be a beam spot. Similarly, when the terminal is located in the south edge region S of the sixth beam spot, the adjacent beam spots will be five in total, and when the terminal is located in the east or west edge region E or W, will be.

While the preferred embodiments of the base station operating method of the mobile communication system of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that various changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims. For example, the setting method of the edge area may be appropriately modified according to the shape of the beam spot.

Claims (4)

A base station is divided into a plurality of beam spots arranged in a matrix by a millimeter wave beam emitted by a plurality of antenna elements, and in a state in which a modem including an RF transmission / reception module is associated with each beam spot, Lt; / RTI > is performed by the scheduler,
The method comprising: (a) switching, if there is no active terminal in a beam spot, a dominant modem of the beam spot to a sleep mode in a power saving mode;
(B) obtaining location information of a terminal from each beam spot having an active terminal and determining whether the terminal is located in an edge region of an arbitrary beam spot;
(C) determining whether an adjacent beam spot belongs to the same base station or an adjacent base station when the terminal is located in an edge region of an arbitrary beam spot as a result of the determination in the step (b);
(D) when the neighboring beam spot belongs to the same base station and the neighboring beam spot is in a sleep mode as a result of the determining in the step (c), the neighboring beam spot is switched to an active mode;
And (e) notifying the beam scheduler of the neighboring base station of the location information of the terminal when the adjacent beam spot belongs to the neighboring base station as a result of the determination in the step (c)
And activating the transmission module of the modem in the sleep mode periodically for a predetermined period of time. The method according to claim 1,
Wherein the location information of the terminal is the geographical coordinate data transmitted by the terminal after being detected by its own GPS receiver. delete 3. The method according to claim 1 or 2,
Activates the transmission module of the modem in the sleep mode every 40 ms to transmit an MIB (Master Information Block), transmits SIB (System Information) every 80 ms,
And activating the reception module of the modem in the sleep mode every 80 ms to wait for reception of a Physical Random Access Channel (PRACH) from the MS.

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