KR20120061741A - M2M device and base station for transmitting and receiving multicast traffic and method thereof - Google Patents

Abstract

PURPOSE: A M2M(Machine to Machine) apparatus for transmitting and receiving multicast traffic, base station, and method thereof are provided to effectively operate an M2M system by receiving downlink multicast data without terminating an idle mode. CONSTITUTION: A processor(120) receives a paging message from a base station(150) by controlling a reception apparatus(112). The processor controls the reception apparatus in order to receive multicast data from the base station based on the paging message. The paging message includes time information related to multicast data transmission time between the base station and an M2M apparatus. The time information directs a frame, a sub frame, or a super-frame number.

Description

M2M device and base station for transmitting and receiving multicast traffic and a method for performing the same {M2M device and base station for transmitting and receiving multicast traffic and method}

The present invention relates to an M2M device and a base station for performing multicast scheduling, and a method of performing the same.

Machine-to-machine communication (M2M) refers to communication between the electronic device and the electronic device as it is. Broadly, it means wired or wireless communication between electronic devices or communication between a device controlled by a person and a machine. Recently, however, it is generally referring to wireless communication between an electronic device and an electronic device, that is, device-to-device performed without human involvement.

In the early 1990s, when the concept of M2M communication was first introduced, it was recognized as a concept of remote control or telematics, and the market itself was very limited. However, in the past few years, M2M communication has been rapidly gaining worldwide attention. Grew. In particular, intelligent metering that measures flow management, remote monitoring of machinery and equipment, operating hours on construction machinery and automatic measurement of heat or electricity usage in point-of-sales and security-related applications. It showed great influence in the field of (Smart Meter). M2M communication in the future will be utilized for more various purposes in connection with existing mobile communication and wireless high-speed Internet, or low-power communication solutions such as Wi-Fi and Zigbee. It will be the foundation to expand into the market.

In the M2M era, any machine equipped with a Subscriber Identity Module (SIM) card can transmit and receive data for remote management and control. For example, M2M communication technology can be used in numerous devices and equipment such as automobiles, trucks, trains, containers, vending machines, gas tanks, and the like.

In the related art, it is common to manage terminals in individual units, so that communication between the base station and the terminals is performed in a one-to-one communication scheme. Assuming that many M2M devices communicate with the base station in this one-to-one communication scheme, network overload due to signaling occurring between each of the M2M devices and the base station is expected. As described above, when M2M communication is rapidly spread and widened, overhead due to communication between these M2M devices or between M2M devices and a base station may be a problem. Accordingly, in order to efficiently solve such overhead problem in consideration of the characteristics of the M2M communication scheme, it is necessary to schedule the M2M device.

An object of the present invention is to provide a method and apparatus for a M2M (Machine to Machine) device to communicate with a base station.

An object of the present invention is to provide a method and apparatus for a base station to communicate with a machine to machine (M2M) device.

Another technical problem to be achieved in the present invention is to provide a machine to machine (M2M) device for communicating with the base station.

Another technical problem to be achieved in the present invention is to provide a base station for communicating with a machine to machine (M2M) device.

According to an aspect of the present invention, there is provided a method for a machine to machine (M2M) to communicate with a base station, the method comprising: receiving a paging message from the base station; And receiving multicast data from the base station based on the paging message, wherein the paging message may include time information indicating a time when the base station transmits the multicast data to the M2M device. The time information may be information indicating a frame number or subframe number or superframe number at which the base station starts transmitting the multicast data. Alternatively, the time information may be a frame offset indicating a waiting time for the M2M device to receive the multicast data. Alternatively, the paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.

In order to achieve the above technical problem, a base station according to the present invention performs a communication with a machine to machine (M2M) device, comprising the steps of: transmitting a paging message to the M2M device; The multicast data may be transmitted to the M2M device based on the paging message, and the paging message may include time information indicating a time when the base station transmits the multicast data to the M2M device. The time information may be information indicating a frame number or subframe number or superframe number at which the base station starts transmitting the multicast data. Alternatively, the time information may be a frame offset indicating a waiting time for the M2M device to receive the multicast data. Alternatively, the paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.

According to another aspect of the present invention, there is provided a Machine to Machine (M2M) device for communicating with a base station, comprising: a receiver for receiving a paging message from the base station; And a processor configured to control the receiver, wherein the processor controls the receiver to receive multicast data from the base station based on the paging message, wherein the paging message is used by the base station to transmit the multicast data to the M2M. It may include time information indicating the time to transmit to the device. The time information may be information indicating a frame number or subframe number or superframe number at which the base station starts transmitting the multicast data. Alternatively, the time information may be a frame offset indicating a waiting time for the M2M device to receive the multicast data. Alternatively, the paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.

According to another aspect of the present invention, there is provided a base station apparatus for communicating with a machine to machine (M2M) device, comprising: a transmitter for transmitting a paging message to the M2M device; And a processor configured to control the transmitter, wherein the processor controls the transmitter to transmit multicast data to an M2M device based on the paging message, wherein the paging message is transmitted by the base station to the M2M. It may include time information indicating the time to transmit to the device. The time information may be information indicating a frame number or subframe number or superframe number at which the base station starts transmitting the multicast data. Alternatively, the time information may be a frame offset indicating a waiting time for the M2M device to receive the multicast data. Alternatively, the paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.

According to various embodiments of the present invention, by using the multicast traffic transmission method proposed in the present invention, it is possible to minimize power consumption of an M2M device and maximize efficient resource usage of the M2M system.

In addition, in the present invention, the M2M device can receive the downlink multicast data without ending the idle mode, thereby efficiently operating the M2M system.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical idea of the present invention.
1 is a diagram for schematically explaining a device configuration such as an M2M device and a base station according to an embodiment of the present invention;
2 is a diagram illustrating multicast data transmission between a terminal and a base station;
3 is a diagram illustrating a process of transmitting multicast traffic between an M2M device and a base station;
4 is a diagram illustrating a process of transmitting multicast traffic between M2M devices having a same paging offset value and a base station;
5 is a diagram illustrating a process of transmitting multicast traffic between M2M devices having different paging offset values and a base station;
6 is a diagram illustrating multicast data transmission between a terminal and a base station according to an embodiment of the present invention;
7 is a diagram illustrating a process of transmitting multicast traffic between an M2M device and a base station according to another embodiment of the present invention;
8 is a diagram illustrating a process of transmitting multicast traffic between an M2M device and a base station according to another embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

On the other hand, in some cases, well-known structures and devices are omitted in order to avoid obscuring the concepts of the present invention, or shown in block diagram form centering on the core functions of each structure and device. In addition, the same components will be described with the same reference numerals throughout the present specification.

In addition, in the following description, it is assumed that a terminal collectively refers to a mobile or fixed user terminal device such as a user equipment (UE), a mobile station (MS), an advanced mobile station (AMS), a machine to machine (M2M) device, and the like. In addition, it is assumed that the base station collectively refers to any node in the network stage that communicates with the terminal, such as a Node B, an eNode B, a Base Station, an Advanced Base Station (ANB), and an Access Point (AP). In this specification, the description will be made based on IEEE 802.16e / m, but the contents of the present invention can be applied to other communication systems such as 3GPPL LTE and LTE-A system.

Hereinafter, communication between M2M devices means information exchange performed through the base station, between the terminals, or between the base station and the terminals without human intervention. Accordingly, the M2M device refers to a terminal capable of supporting communication of the M2M device as described above. An access service network for an M2M service is defined as an M2M ASN (M2M Access Service Network), and a network entity communicating with M2M devices is called an M2M server. The M2M server executes an M2M application and provides an M2M specific service for one or more M2M devices. An M2M feature is a feature of an M2M application, and one or more features may be needed to provide the application. An M2M device group refers to a group of M2M devices that share one or more features in common.

Devices communicating in an M2M manner (which may be variously called M2M devices, M2M communication devices, etc.) will gradually increase in a certain network as the machine application type increases. The types of device applications under discussion include (1) security, (2) public safety, (3) tracking and tracing, (4) payment, and (5) healthcare. health care, (6) remote maintenance and control, (7) metering, (8) consumer devices, (9) point of sales (POS) and In the security-related application market, Logistics Management, (10) Vending Machine-to-Vending Machine Communication, (11) Remote Monitoring of Machines and Facilities, Hours of Operation on Construction Machinery Equipment and Automatic Measurement of Heat or Electricity Usage Smart Meter, (12) Surveillance Video communication of a surveillance camera, etc., but need not be limited thereto, and various device application types have been discussed.

Another characteristic of M2M devices is low mobility or no mobility. Significantly less or no mobility means that M2M devices are stationary for a long time. An M2M communication system is a specific M2M with a fixed location, such as secured access and surveillance, public safety, payment, remote maintenance and control, metering, and so on. Mobility-related operations for the application can be simplified or optimized.

As the device application type increases, the number of M2M communication devices may increase dramatically compared to the number of general mobile communication devices. Therefore, if they all communicate with the base station individually, it can put a serious load on the air interface and the network.

Hereinafter, an embodiment of the present invention will be described by exemplifying a case where M2M communication is applied to IEEE 802.16e / m. However, the present invention is not limited thereto, and the embodiment of the present invention may be applied to other systems such as 3GPP LTE system in the same manner.

1 is a diagram for schematically explaining a device configuration such as an M2M device and a base station according to an embodiment of the present invention.

In FIG. 1, the M2M device 100 (or may be referred to as an M2M communication device, hereinafter referred to as an M2M device) and the base station 150 are RF units 110 and 160, processors 120 and 170, and optionally, respectively. Memory 130 and 180. In addition, each of the RF units 110 and 160 may include transmitters 111 and 161 and receivers 112 and 162. For example of the M2M device 100, the transmitter 111 and the receiver 112 are configured to transmit and receive signals with the base station 150 and other M2M devices, and the processor 120 is the transmitter 111 and the receiver. Functionally connected to 112, the transmitter 111 and the receiver 112 may be configured to control a process of transmitting and receiving signals with other devices. In addition, the processor 120 may perform various types of processing on the signal to be transmitted and then transmit the signal to the transmitter 111, and may perform processing on the signal received by the receiver 112. If necessary, the processor 120 may store information included in the exchanged message in the memory 130. With such a structure, the M2M device 100 may perform the methods of the various embodiments described below. Although not shown in FIG. 1, the M2M device 100 may include various additional configurations according to the device application type. When the M2M device 100 is for intelligent metering, the M2M device 100 may include an additional configuration for power measurement, and the like. The power measurement operation may be performed by the processor 120 illustrated in FIG. 1. May be controlled, or may be controlled by a separately configured processor (not shown).

1 illustrates an example in which communication is performed between the M2M device 100 and the base station 150, the M2M communication method according to the present invention may occur between M2M devices, and each of the devices is shown in FIG. 1. The method according to various embodiments described below may be performed in the same form as each device configuration shown in FIG.

Transmitter 161 and receiver 162 of base station 150 are configured to transmit and receive signals with other base stations, M2M servers, and M2M devices, and processor 170 is functional with transmitter 161 and receiver 162. Connected to, the transmitter 161 and the receiver 162 may be configured to control the process of transmitting and receiving signals with other devices. In addition, the processor 170 may perform various processing on the signal to be transmitted and then transmit the signal to the transmitter 161, and may perform the processing on the signal received by the receiver 162. If necessary, the processor 170 may store information included in the exchanged message in the memory 130. With this structure, the base station 150 may perform the methods of the various embodiments described above.

Processors 120 and 170 of each of the M2M device 110 and the base station 150 instruct (eg, control, coordinate, manage, etc.) operation at the M2M device 110 and the base station 150, respectively. Each of the processors 120 and 170 may be connected to memories 130 and 180 that store program codes and data. The memories 130 and 180 are coupled to the processors 120 and 170 to store operating systems, applications, and general files.

The processors 120 and 170 may also be referred to as a controller, a microcontroller, a microprocessor, a microcomputer, or the like. The processors 120 and 170 may be implemented by hardware or firmware, software, or a combination thereof. When implementing embodiments of the present invention using hardware, application specific integrated circuits (ASICs) or digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) configured to perform the present invention. Field programmable gate arrays (FPGAs) may be provided in the processors 120 and 170.

Meanwhile, when implementing embodiments of the present invention using firmware or software, the firmware or software may be configured to include a module, a procedure, or a function for performing the functions or operations of the present invention, and to perform the present invention. Firmware or software configured to be may be included in the processors 120 and 170 or may be stored in the memories 130 and 180 to be driven by the processors 120 and 170.

In the following description, the idle mode refers to a paging group, a paging cycle, and a paging offset that are approved by the base station through signaling between the terminal and the base station in order to save power of the terminal. Offset) mode. That is, even if the terminal roams a radio link environment having a plurality of base stations over a wide area, it is a mechanism that can periodically receive a downlink broadcast message without registering with a specific base station.

Idle mode stops all normal operations as well as handover (HO), and tailors only downlink synchronization to receive paging messages, which are broadcast messages only over a period of time. It is set. The paging message is a message instructing the paging action (paging action) to the terminal. For example, paging operations include ranging, network reentry, and the like.

The idle mode may be initiated by the terminal or initiated by the base station. That is, the terminal may enter the idle mode by transmitting a deregistration request (DREG-REQ) message to the base station and receiving a deregistration response (DREG-RSP) message from the base station in response thereto. In addition, the base station may enter the idle mode by transmitting a non-registration deregistration response (DREG-RSP) message or a deregistration command (DREG-CMD) message to the terminal.

When the terminal receives a paging message corresponding to itself during the Available Interval (AI) in the idle mode, the terminal switches to the connected mode through a network entry process and transmits and receives data. .

Idle State or Idle Mode operation generally supports downlink broadcast traffic transmission even when the UE moves in a radio link environment composed of multiple base stations, even if the UE does not register with a specific base station. It refers to the action that makes. When the terminal does not receive traffic from the base station for a certain time, the terminal may transition to the idle state to save power. The terminal transitioning to the idle mode receives a broadcast message (eg, paging message) broadcasted by the base station during an available interval (AI) and transitions to the normal mode or remains idle. You can judge.

The idle state can benefit the terminal by eliminating the active and general operational requirements associated with the handover. The idle state may limit the terminal activity to be scanned in discrete cycles, thereby saving power and operational resources used by the terminal. In addition, the idle state provides a simple and appropriate way to inform the terminal of downlink traffic pending, and removes the network interface and network handover (HO) traffic from the inactive terminal. The base station can benefit.

Paging refers to a function of identifying a location (eg, any base station or a switching center) of a corresponding terminal when an incoming call occurs in mobile communication. A plurality of base stations supporting the idle state or the idle mode may belong to a specific paging group to configure a paging area. At this time, the paging group represents a logical group. The purpose of a paging group is to provide an adjacent coverage area that can be paged in downlink if there is traffic targeting the terminal. The paging group is preferably configured to meet the condition that a particular terminal is large enough to exist for most of the time in the same paging group, and that the paging load should be small enough to maintain an appropriate level.

The paging group may include one or more base stations, and one base station may be included in one or more paging groups. Paging groups are defined in the management system. Paging groups can use paging group-action backbone network messages. In addition, the paging controller may manage a list of idle terminals and manage initial paging of all base stations belonging to a paging group by using a paging-announce message, which is one of backbone network messages.

Paging in idle mode is described based on IEEE 802.16 system for convenience of description. However, the technical idea of the present invention is not limited thereto. The terminal transmits a deregistration request (DREG-REQ) message to the base station to request deregistration with the base station to enter the idle mode. Thereafter, the base station transmits a deregistration response (DREG-RSP) message to the terminal in response to the DREG-REQ message. At this time, the DREG-RSP message includes paging information. Here, entry into the idle mode of the terminal may be initiated by a request of the base station. In this case, the base station transmits a DREG-RSP message to the terminal.

The paging information may include a paging cycle, a paging offset, a paging group identifier (PGID), a paging listening interval (Paging Listening Interval) value, and the like.

The terminal receiving the DREG-RSP message from the base station enters the idle mode with reference to the paging information. The idle mode has a paging cycle, and one paging cycle may consist of an available interval and an unavailable interval. In this case, the usable interval is the same concept as the paging listening interval or the paging interval. The paging offset indicates a time point (eg, a frame or subframe) at which a paging segment starts within a paging period. In addition, the paging group identifier indicates the identifier of the paging group assigned to the terminal. In addition, the paging information may include paging message offset information. Here, the paging message offset information indicates a time point at which the paging message is transmitted from the base station. Subsequently, the terminal may receive a paging message delivered to the user in an available period, that is, a paging listening interval using the paging information. Here, the paging message may be transmitted through the base station or the paging controller. That is, the terminal monitors the radio channel according to a paging period in order to receive a paging message.

The terminal in the idle mode receives a paging message in its paging listening interval and checks whether there is downlink (DL) data transmitted to the terminal. If there is downlink data (ie, a positive indication), the terminal performs a network reentry process including a ranging process. Thereafter, a process of establishing a connection for a related downlink service flow is performed through a dynamic service addition (DSA) process. After the connection for the service flow is established, the base station transmits downlink data for the service to the terminal.

2 is a diagram illustrating an example of downlink data transmission between a terminal and a base station. In the invention according to FIG. 2, the terminal performs a network reentry after receiving a paging message in order to receive downlink traffic by the terminal in idle mode in an existing system.

The UE in the idle mode receives a paging message in its paging listening interval and checks whether there is downlink data transmitted to it. If there is downlink data (DL data) (ie, a positive indication), the terminal performs a network reentry procedure including a ranging process. Thereafter, a process of establishing a connection to a related downlink (DL) service flow is performed through a dynamic service addition (DSA) process. When the connection for the service flow is established, the base station transmits downlink data (DL data) for the service to the terminal.

Since most M2M devices in the M2M scenario are not owned by the user as existing terminals such as mobile phones, the automatic application or firmware update process for M2M devices is an M2M service scenario. It can be a major application in. For example, in order to update firmware of each device, the M2M server may transmit updated information to M2M devices having a corresponding application. In order to transmit such multicast data that needs to be transmitted to multiple terminals in common to M2M devices in idle mode, the base station according to the embodiment of FIG. 2 will page the corresponding M2M devices. The terminal receiving the paged starts the transmission of a random access code, performs a network reentry process, accesses the network, and receives DL traffic transmitted from the base station. These processes increase the use of unnecessary resources of the network and also increase the power consumption of the terminal.

In order to solve the above problems, when transmitting multicast data generated in the event triggered method to the terminal in the idle mode (Idle Mode) in the M2M communication according to the present invention, paging By using the method, an idle mode M2M device may provide multicast data efficiently.

3 is a diagram illustrating an example of multicast data transmission between a terminal and a base station according to an embodiment of the present invention.

When the base station receives downlink multicast data from the network, the base station first downloads the downlink multicast data to the terminals in the idle mode before transmitting the downlink multicast data to the terminals in the cell. The paging message indicates that there is DL multicast data. To this end, the paging message is transmitted by including a multicast traffic indication (e.g., Action code = 0b10, related ID (M2M group ID)). Idle mode When the terminal receives a paging message, it checks whether there is a multicast traffic indication, and if so, the group belonging to the terminal (or multicast data allocated to the terminal). Check that the M2M group ID for the ID) is included. If there is an ID corresponding to the terminal, the terminal performs an operation of receiving downlink multicast data while maintaining an idle mode (that is, without performing network reentry). do.

4 is a diagram illustrating a process of transmitting multicast traffic between M2M devices having a same paging offset value and a base station.

In FIG. 4, an action code in which a terminal in idle mode is a multicast traffic indicator, which is a multicast traffic indicator, is a multicast traffic indicator to a base station during a listening interval or an available interval (AI). If (Action code) indicates 0b10, receives M2M Group ID to receive multicast traffic, and is a group to which it belongs, the terminal does not receive network reentry. Wait for).

In this scenario, if the base station does not have downlink (DL) resources for transmitting multicast data right now, and transmits multicast data after a long time after paging (terminal) They continue to transmit data on the downlink channel until multicast data is transmitted (eg, downlink control channel information such as A-MAP or MAP, broadcast control such as SCD, SII-ADV, ULPC-NI, etc.). MAC messages should be received and decoded. This may increase unnecessary power consumption of the terminal.

5 is a diagram illustrating a process of transmitting multicast traffic between M2M devices having different paging offset values and a base station.

If terminals belonging to one M2M group belong to the same group and are assigned different paging offsets or belong to different paging groups, terminals assigned the same MGID are actually subjected to multicast paging. The viewpoint may be different, and thus, among terminals belonging to the same M2M group, specific terminals may have longer time to wait to receive multicast data than other terminals. 5 shows an example of this. Terminals with one paging offset 1, 2, 3 have been assigned the same MGID = 1, and in this scenario, terminals with paging offset 3 have terminals with paging offset 1 You will have a longer waiting time. This causes a problem of increasing unnecessary power consumption of terminals having a paging offset (3).

To solve this problem, the present invention proposes the following embodiments. Multicast transmission start time (MTST) is described in a paging message (AAI-PAG-ADV message in IEEE 802.16m, MOB_PAG-ADV message in IEEE 802.16e, and the present invention is mainly described based on IEEE 802.16m AAI-PAG-ADV). Include and send. Idle mode When the terminal receives the paging message, the terminal remains in idle mode (ie, does not perform network reentry), according to MTST, downlink multi Performs the operation of receiving DL multicast data.

6 is a diagram illustrating transmission and reception of multicast data between an M2M device and a base station according to an embodiment of the present invention.

If the base station of the present invention has multicast data for certain M2M devices, when the paging message is transmitted to the M2M devices, the base station includes the MTST in the paging message. If there is multicast data for a specific M2M group, the base station of the present invention may transmit the MTST together with or in the paging message for paging the specific M2M group. Alternatively, the MTST may be transmitted only if the related multicast data cannot be transmitted immediately after the paging message is transmitted. When the M2M device receives the paging message (AAI-PAG-ADV) in its paging listening interval, it checks whether the multicast transmission start time (MTST) is included in the paging message. If a multicast transmission start time (MTST) is included, the M2M device may perform a power down operation to reduce power consumption before the superframe / frame / subframe indicated by the MTST. . That is, an operation of receiving multicast data from the superframe / frame / subframe indicated by the MTST will be performed. The MTST may be a superframe number / frame number / subframe number at which the base station starts transmitting downlink multicast data. Alternatively, MTST is a time waiting for the start of transmission of downlink multicast data based on a time point when the M2M device receives the paging message, and may mean a frame offset. In addition, the unit indicating the MTST may be a frame unit, a subframe unit, or a superframe unit (20 ms). As shown in FIG. 6, the paging message PAG-ADV may include an MTST. Each M2M device may include different paging offset values, and as shown in FIG. 6, paging offsets 1, 2, and 3 have different values. M2M devices having paging offsets 2 and 3 cannot transmit multicast data immediately after sending a paging message. Accordingly, M2M devices having paging offsets 2 and 3 may perform a power down operation to reduce power consumption until the superframe / frame / subframe indicated by the MTST included in the page message. That is, M2M devices having paging offset 2 and M2M devices having paging offset 3 may perform a power down operation during the superframe / frame / subframe indicated by the MTST.

For reference, the frame number indicated by the MTST may be calculated based on a superframe number in the IEEE 802.11m system. That is, the frame number is set to "superframe number-1) * 4". In contrast, in the IEEE 802.11e system, a frame number is present in the MAP and transmitted every frame.

Through the above operation, when the base station transmits multicast data generated by an event triggered method to a fixed M2M device, an idle mode is used by using a paging method. mode) The M2M device can efficiently provide multicast data without ending the idle mode.

In the above-described embodiment of the present invention, the paging message may be transmitted as follows.

Table 1 below shows an AAI-PAG-ADV format as an example in which a multicast traffic indication and an MGID are included in a paging message.

Fields Size Value Condition For (i = 0; i <Num_MGID; i ++) { Num_MGID indicates the number of MGIDs included in this paging message [0..63] MGID 12 M2M Group ID Action code 2 0b00: Performing network reentry
0b01: Performing location update
0b10: Receiving multicast traffic
0b11: reserved }

Referring to Table 1, the base station may deliver the MGID to the M2M device. The MGID field means an M2M group ID and may be represented by 12 bits. In addition, Num_MGID indicates the number of MGIDs included in the paging message. The base station may include an action code field in the paging message and deliver it to the M2M device. This action code field indicates the purpose of this paging message. For example, the purpose of this paging message is '0b00' to indicate network re-entry, '0b01' to indicate paging for location update, and '0b10' to indicate reception of multicast traffic. If the action indicates a reserved state, '0b11' may indicate the action.

However, if terminals belonging to one M2M group belong to the same group and are assigned different paging offsets or belong to different paging groups, the terminals assigned the same MGID are actually multicast paging. The time point for receiving a message may vary, and thus, among terminals belonging to the same M2M group, specific terminals may have longer time to wait to receive multicast data than other terminals.

In order to solve the above problem, when the base station of the present invention transmits a paging message including a multicast traffic indication, the base station receives time information at which the base station starts transmitting the multicast data. It is included in the paging message and transmitted. The terminal may receive the paging message and power down to reduce power consumption before the start time of multicast data transmission included in the paging message. 7 and 8 show an embodiment thereof.

4 and 5 may be used together with the embodiment of FIG. 6. That is, the paging message may include an MTST, as described in FIG. 6, and the paging message including the MTST further includes an MGID and an action code as described in FIGS. 4 and 5. Can be described.

7 is a diagram illustrating a process of transmitting multicast traffic between an M2M device and a base station according to another embodiment of the present invention. In particular, FIG. 7 illustrates an embodiment in which an MTST indicating an absolute time at which a base station starts transmitting multicast data is transmitted from the base station to the M2M device.

A base station that wants to transmit multicast data to certain M2M devices transmits a paging message including the MGID of the M2M group to which the predetermined M2M devices belong and the MTST indicating the time to transmit the multicast data. The M2M device receives a paging message (AAI-PAG-ADV) in its paging listening interval. The M2M device checks whether the paging message is a message for the M2M device by using the MGID assigned to the M2M device. When the target of the paging message is the M2M device and the action code of the paging message is set to 0b10, which is a multicast traffic indication, the M2M device starts time of multicast transmission included in the paging message. Check (MTST: multicast transmission start time). If the MTST is included in the paging message, the M2M device may perform a power down operation to reduce power consumption until the frame indicated by the MTST. That is, the M2M device will perform an operation of receiving the multicast data from the frame indicated by the MTST.

Referring to FIG. 7, the base station transmits a paging message including a multicast traffic indication (MTST) and a MTST to terminals having a paging offset 2 and a paging offset 3. Can transmit In this case, it is assumed that each MTST indicates a frame having a frame number of 42. Paging offset 2 terminals and paging offset 3 terminals receive a paging message, and then receive multicast data when the frame number is 42 In addition, an operation for reducing power consumption may be performed until the corresponding frame.

Table 2 below shows an AAI-PAG-ADV format, which is an example of a paging message including a multicast transmission start time (MTST).

Fields Size Value Condition … … … … For (i = 0; i <Num_MGID; i ++) { Num_MGID indicates the number of MGIDs included in this paging message [0..63] MGID 12 M2M Group ID Action code 2 0b00: Performing network reentry
0b01: Performing location update
0b10: Receiving multicast traffic
0b11: reserved If (Action code == 0b10) { Multicast transmission  start time  ( MTST ) 8 Least Significant  8 bits of the frame number  in which the ABS starts sending DL  multicast data . Shall be present when the  MTST needs to be  included in this message } … … … } … … … …

In Table 2, since the meanings of the MGID field and the action code field are the same as those in Table 1, the description of the specific meaning of these fields is omitted.

The base station may transmit information indicating the absolute time of transmitting the corresponding multicast data to the M2M devices as MTST. Referring to Table 2, for example, the base station may transmit the frame number at which the multicast data starts to be transmitted to the M2M devices that are the targets of the multicast data as MTST. A terminal to which the multicast data is transmitted may perform a power down operation until a frame indicated by the MTST, thereby reducing power consumption. That is, the reception of multicast data can be started from the frame indicated by the MTST.

8 is a diagram illustrating a process of transmitting multicast traffic between an M2M device and a base station according to another embodiment of the present invention. In particular, FIG. 8 illustrates an embodiment in which an MTST indicating a relative time at which a base station starts transmitting multicast data is transmitted from the base station to the M2M device. In the embodiment of FIG. 7, information indicating a superframe, a frame, or a subframe in which reception of multicast data should be started to the corresponding M2M device is in the form of an absolute value (for example, a superframe number or a frame number or a subframe number). 8, the M2M device transmits an offset value indicating a time to wait before the M2M device receives the multicast data.

Referring to FIG. 8, when the base station delivers a multicast traffic indication (MTST) as a paging message to terminals having a paging offset 2 and a paging offset 3, the base station transmits a multicast traffic indication (MTST) as a paging message. Transmit with MTST in paging message. According to the present embodiment, the MTST corresponds to an offset value indicating the waiting time for the M2M devices to receive the multicast data. For example, referring to FIG. 8, MTST values for paging offset 2 terminal and paging offset 3 are 32 and 42 frames, respectively. Paging Offset (paging offset) 2 After receiving the paging message (paging offset), the UE performs an operation to receive multicast data after 32 frames, and to reduce the power consumption to the corresponding frame Can be. Paging offset (paging offset) 3 After receiving the paging message (paging offset), the UE performs an operation for receiving multicast data from 42 frames, and to reduce the power consumption to the frame Can be.

Table 3 below shows another example of a paging message AAI-PAG-ADV format including a multicast transmission start time.

Fields Size Value Condition … … … … For (i = 0; i <Num_MGID; i ++) { Num_MGID indicates the number of MGIDs included in this paging message [0..63] MGID 12 M2M Group ID Action code 2 0b00: Performing network reentry
0b01: Performing location update
0b10: Receiving multicast traffic
0b11: reserved If (Action code == 0b10) { Multicast transmission  start time  ( MTST ) 8 The frame offset in which the ABS starts  sending DL multicast data .
00000000: current frame
00000001: 1 frame  Transfer behind
00000010: 2 frames  Transfer behind
…
11111111: Transmission after 255 frames Shall be present when the  MTST needs to be  included in this message } … … … } … … … …

In Table 2, the MTST is a frame number, whereas in Table 3, the MTST indicates a frame offset.

Referring to Table 3, MTST is a time waiting for the start of the transmission of the downlink multicast data, based on the time when the M2M device receives the paging message, may mean a frame offset (frame offset). That is, MTST is a frame offset value indicating the waiting time for M2M device to receive the multicast data.

In the IEEE 802.16e-based M2M system, the operation of the UE performed after receiving the MTST is the same as that of IEEE 802.16m. That is, in an IEEE 802.16e based M2M system, M2M devices can reduce power consumption until MTST when receiving MOB_PAG-ADV including MTST.

In addition, although the unit indicating the MTST is described in units of frames, the unit may be displayed by being changed to a subframe unit or a superframe unit (20 ms).

Table 4 below shows another example of a paging message including a multicast transmission start time.

Table 4 below shows that each M2M group paging parameter (TLV) may be included in a MOB_PAG-ADV message. The MTST of Table 4 may be in a TLV, which is an M2M group paging parameter.

Name Type Length value multicast traffic start time (MTST) X.2 One Least Significant 8 bits of the frame number in which the ABS starts sending DL multicast data

In Table 4, the MTST is included in the MOB_PAG-ADV message so that the base station can transmit to the M2M devices. In addition, the MTST may be included in an MOB_PAG-ADV message and transmitted along with an action code. When the action code, which is the multicast traffic indication, indicates 0b10, the M2M device can receive multicast traffic without performing reentry of the network. If the action code, which is the multicast traffic indicator, indicates 0b10, and includes the MTST, it will perform the operation of receiving multicast data from the frame indicated by the MTST. Table 4 can operate in an IEEE 802.16e-based M2M system, and the unit representing the MTST is indicated in a frame unit, but the unit is a subframe unit or a superframe unit (20ms). Can be

Referring to FIG. 1, a processor (hereinafter, referred to as a base station processor) of a base station according to an embodiment of the present invention provides a paging message for paging the M2M devices to transmit multicast data for one or more (mainly, plural) M2M devices. Can be generated. The base station processor is configured to include the paging to include information (eg, MGID) identifying an M2M group to which the M2M devices belong and / or information indicating the presence of the multicast data (eg, an action code set to 0b10). You can create a message. Further, the base station processor may generate the paging message to include time information indicating a time at which the base station starts transmitting the multicast data. The base station processor may control a transmitter (hereinafter, referred to as a base station transmitter) of the base station to transmit the paging message to the M2M devices. The base station processor controls the base station transmitter to start transmission of the multicast data at a time indicated by the time information.

The processor of the M2M device (hereinafter, referred to as an M2M processor) controls the receiver of the M2M device (hereinafter, referred to as an M2M receiver) to receive the paging message from the base station in a listening interval of the M2M device. The M2M processor may determine whether the paging message is a message associated with the M2M device using M2M device group information included in the paging message. In addition, the M2M processor may recognize the presence of multicast data to be received by the M2M device using the paging message, for example, using an action code in the paging message. The M2M processor may use the time information included in the paging message to know when the M2M device should receive the multicast data from the base station. The M2M processor may power down the M2M device until the time when the multicast data should be received using the time information. The M2M processor may receive the multicast data from the base station by increasing the reception power of the M2M receiver from a time indicated or inferred by the time information. The M2M receiver may receive the multicast data from the base station at a time indicated by the time information under the control of the M2M processor.

According to the above-described embodiments of the present invention, if there is an ID corresponding to the terminal, the terminal remains in idle mode (ie, does not perform network reentry) and does not terminate the idle mode. In addition, the M2M system can be efficiently operated by receiving downlink multicast data.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or TLV feature may be implemented in a form that is not combined with other components or features. In addition, it is also possible to combine the some components and / or features to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is obvious that the embodiments can be combined to form a new claim by combining claims which are not expressly cited in the claims or by post-application correction.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above detailed description should not be interpreted as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Claims (16)

In the M2M (Machine to Machine) device to communicate with the base station,
Receiving a paging message from the base station; And
Receiving multicast data from the base station based on the paging message,
The paging message includes time information indicating the time when the base station transmits the multicast data to the M2M device,
How to perform communication of M2M device. The method of claim 1,
The time information is characterized in that the information indicating the frame number or subframe number or superframe number at which the base station starts the transmission of the multicast data,
How to perform communication of M2M device. The method of claim 1,
The time information is characterized in that the frame offset indicating the waiting time for the M2M device to receive the multicast data,
How to perform communication of M2M device. 4. The method according to any one of claims 1 to 3,
The paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.
How to perform communication of M2M device. In the method that the base station communicates with a machine to machine (M2M) device,
Sending a paging message to the M2M device;
Sending multicast data to the M2M device based on the paging message,
The paging message includes time information indicating the time when the base station transmits the multicast data to the M2M device,
Method of communication of a base station. 6. The method of claim 5,
The time information is characterized in that the information indicating the frame number or subframe number or superframe number at which the base station starts the transmission of the multicast data,
Method of communication of a base station. 6. The method of claim 5,
The time information is characterized in that the frame offset indicating the waiting time for the M2M device to receive the multicast data,
Method of communication of a base station. 8. The method according to any one of claims 5 to 7,
The paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.
Method of communication of a base station. In the M2M (Machine to Machine) device for communicating with the base station,
receiving set; And
A processor configured to control the receiver,
The processor controls the receiver to receive a paging message from the base station, and controls the receiver to receive multicast data from the base station based on the paging message,
The paging message includes time information indicating the time when the base station transmits the multicast data to the M2M device,
M2M device. The method of claim 9,
The time information is characterized in that the information indicating the frame number or subframe number or superframe number at which the base station starts the transmission of the multicast data,
M2M device. The method of claim 9,
The time information is characterized in that the frame offset indicating the waiting time for the M2M device to receive the multicast data,
M2M device. The method according to claim 9, wherein
The paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.
M2M device. A base station apparatus for communicating with a machine to machine (M2M) device,
transmitter; And
A processor configured to control the transmitter;
The processor controls the transmitter to send a paging message to the M2M device, and controls the transmitter to send multicast data to the M2M device based on the paging message,
The paging message includes time information indicating the time when the base station transmits the multicast data to the M2M device,
Base station. The method of claim 13,
The time information is characterized in that the information indicating the frame number or subframe number or superframe number at which the base station starts the transmission of the multicast data,
Base station. The method of claim 13,
The time information is characterized in that the frame offset indicating the waiting time for the M2M device to receive the multicast data,
Base station. The method according to claim 13 to 15,
The paging message may further include a multicast traffic indicator indicating whether to transmit the multicast data and an M2M device group identifier indicating an M2M group to which the multicast data is to be transmitted.
Base station.

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