KR20100005618A

KR20100005618A - Method for transmitting media access control protocol date unit

Info

Publication number: KR20100005618A
Application number: KR1020080065717A
Authority: KR
Inventors: 류기선; 육영수
Original assignee: 엘지전자 주식회사
Priority date: 2008-07-07
Filing date: 2008-07-07
Publication date: 2010-01-15

Abstract

The present invention discloses a method for optimizing a header used in a media access control layer in a radio access system. In one embodiment of the present invention, a method for transmitting a media access control protocol data unit (MAC PDU) may include allocating a unique flow identifier to a terminal and configuring a MAC header including the flow identifier when establishing a service connection. And transmitting the MAC PDU including the MAC header. In this case, the flow identifier is preferably used for addressing and service classification of the MAC PDU.

Description

Method for transmitting Media Access Control Protocol Date Unit

The present invention relates to a wireless access system. The present invention also relates to a method for optimizing a header used in a media access control layer in a wireless access system, and a method for transmitting a physical access control protocol data unit including the header.

Hereinafter, a media access control protocol data unit (MAC PDU) used in a media access control (MAC) layer will be briefly described.

In general, two or less MAC layers (MAC or link layer) and physical layer (Phy layer) use different protocols depending on the wireless access system such as LAN, wireless LAN, 3GPP / 3GPP2 or wireless MAN. . Therefore, the header format of the MAC PDU according to each radio access system is defined differently.

1 illustrates an example of a MAC PDU type in an IEEE 802.16 system, which is one of wireless access systems.

Referring to FIG. 1, a MAC PDU may include a generic MAC header, a payload, and a cyclic redundancy check (CRC) field. The generic MAC header is used for data transfer between nodes in the link layer. The general MAC header may include an address (MAC address) or a link address (Link Address), and may include header error checking and link layer control information.

The payload represents a part including actual data to be transmitted in the MAC PDU. In addition, the CRC refers to a method of determining a check value for checking whether there is an error in the transmitted data when transmitting data through a network or the like. However, although the general MAC header is necessarily included in the MAC PDU, the payload and the CRC may be optionally included.

In general, a connection identifier (CID) included in a MAC header or a map is used differently as an identifier for resource allocation and service classification. At this time, each identifier can be optimized according to the purpose. For example, the size of the identifier for the unicast connection, the resource allocation identifier included in the MAP is optimized to 16 bits (or 14 bits or 12 bits) and the flow identifier to 4 bits (or 6 bits). can do. In this case, a management CID such as a basic CID and a primary CID may be defined in a fixed form.

However, in the multicast connection for providing a multicast and broadcast service (MBS), when using identifiers optimized for unicast connection, sufficient MBS cannot be supported due to the limited identifier size. In addition, when the flow identifier is optimized for the MBS, the identifiers included in the MAC header of the unicast connection may not be optimized, resulting in waste of resources.

The present invention has been made to solve the problems of the general technology as described above.

It is an object of the present invention to provide a method for efficient data communication.

Another object of the present invention is to provide a newly defined Resource Assignment ID and Flow ID in embodiments of the present invention.

It is yet another object of the present invention to provide an optimized MAC header structure that can support resource allocation identifiers and flow identifiers.

It is still another object of the present invention to provide a method of reducing MAC overhead and efficiently using radio resources by using the MAC header.

In order to solve the above technical problem, this document discloses a method for optimizing a header used in a media access control layer and a method for transmitting a media access control protocol data unit including the header in a radio access system.

According to an aspect of the present invention, a method for transmitting a medium access control protocol data unit (MAC PDU) may include: assigning a unique flow identifier to a terminal when establishing a service connection, and configuring a MAC header including the flow identifier; And transmitting the MAC PDU including the MAC header. In this case, the flow identifier is preferably used for addressing and service classification of the MAC PDU.

In addition, an aspect of the present invention may further include transmitting a MAP message including a resource allocation connection identifier (RACID) for resource allocation. In this case, the resource allocation connection identifier preferably has a size larger than the flow identifier. In addition, the service connection is a multicast and broadcast service connection, the flow identifier and resource allocation connection identifier is preferably assigned to the terminal when the multicast and broadcast service connection is established.

In addition, in one aspect of the present invention, the MAC header further includes only a header type field, a subheader field indicating whether a subheader included in the MAC PDU is present, and a field indicating a size of the MAC PDU, and the MAC header is unicast. Can be used for connection. In this case, preferably, the MAC PDU further includes an extended subheader including an extended subheader group length field, an extended subheader type field, and an extended subheader body. In addition, the flow identifier may further include information about a cyclic redundancy check field, an encryption control field, and an encryption key sequence.

In addition, in one aspect of the present invention, the MAC header may further include only a header type field, a subheader field indicating whether a subheader included in the MAC PDU is present, and a field indicating the size of the MAC PDU. In this case, the MAC header is preferably used to connect a multicast broadcast service (MBS). In addition, the MAC header further includes a header check sequence for error detection of the MAC header, and the flow identifier preferably has a fixed value for indicating a multicast broadcast service (MBS) connection. In addition, the flow identifier has a fixed value for indicating the MBS flow, the extended subheader type field indicates the MBS Flow ID included in the extended subheader body, and the extended The subheader body field may include an MBS flow identifier.

In another aspect of the present invention, a method for transmitting a medium access control protocol data unit (MAC PDU) includes a step of assigning a unique flow identifier to a terminal when establishing a service connection from a base station and selectively transmitting or receiving data using the flow identifier. And configuring the MAC header including the flow identifier and forwarding the MAC PDU including the MAC header to a higher layer.

In another aspect of the present invention, a method for transmitting a medium access control protocol data unit (MAC PDU) may include: assigning a unique flow identifier to a terminal when establishing a service connection from a base station and resource allocation indicating an uplink resource region from the base station; Receiving an uplink map message including a connection identifier, configuring an uplink MAC header including a flow identifier, and transmitting a MAC PDU including an uplink MAC header to a base station through an uplink resource zone; It may include.

According to the present invention has the following effects.

First, by utilizing the embodiments of the present invention, efficient data communication can be performed.

Second, by using the flow identifier and / or resource allocation connection identifier newly defined in the present invention, it is possible to use an optimized MAC header structure than when using a general connection identifier.

Third, the overhead of the MAC header can be reduced by different structures of the MAC header used for unicast connection and the MAC header used for multicast and broadcast connection.

Fourth, by newly defining the MBS flow identifier, the MAC header structure used for unicast connection can be used for MBS connection. Thus, by using the same MAC header structure in separate services, the complexity of the system can be reduced.

Fifth, by using the MAC header proposed in the embodiments of the present invention, it is possible to reduce MAC overhead and efficiently use radio resources.

The present invention relates to a wireless access system. In particular, a method of optimizing a header used in a media access control layer in a radio access system and a method of transmitting a media access control protocol data unit including the header are disclosed.

The following embodiments combine the components and features of the present invention in a predetermined form. Each component or feature may be considered to be optional unless otherwise stated. Each component or feature may be embodied in a form that is not combined with other components or features. In addition, some components and / or features may be combined 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.

In the description of the drawings, procedures or steps, which may obscure the gist of the present invention, are not described, and procedures or steps that can be understood by those skilled in the art are not described.

In the present specification, embodiments of the present invention have been described based on data transmission / reception relations between a base station and a terminal. Here, the base station has a meaning as a terminal node of the network that directly communicates with the terminal. The specific operation described as performed by the base station in this document may be performed by an upper node of the base station in some cases.

That is, it is obvious that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, the term "terminal" may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), and the like.

In addition, the transmitting end refers to a node transmitting data or voice service, and the receiving end refers to a node receiving data or voice service. Therefore, in uplink, a terminal may be a transmitting end and a base station may be a receiving end. Similarly, in downlink, a terminal may be a receiving end and a base station may be a transmitting end.

On the other hand, the mobile terminal of the present invention PDA (Personal Digital Assistant), cellular phone, PCS (Personal Communication Service) phone, GSM (Global System for Mobile) phone, WCDMA (Wideband CDMA) phone, MBS (Mobile Broadband System) phone And the like can be used.

Embodiments of the invention may be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of a hardware implementation, the method according to embodiments of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs). Field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to the embodiments of the present invention may be implemented in the form of a module, a procedure, or a function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of the specific terms may be modified in other forms without departing from the technical spirit of the present invention.

2 is a diagram illustrating an example of a MAC header used in an IEEE 802.16 system.

Referring to FIG. 2, the MAC header includes a header type (HT) field, an encryption control (EC) field, a type field, an extended subheader field (ESF), and a CRC indication ( It may include a CI: CRC Indication, an Encryption Key Sequence field, a LEN field, a CID, and a header check sequence (HCS).

The header type (HT) field indicates a header type and indicates whether the corresponding PDU is a general MAC header including a payload or a signaling header for controlling a bandwidth request.

The encryption control (EC) field indicates whether the payload is encrypted. The Type field indicates whether a subheader exists after the header and the type of the subheader. The extended subheader field (ESF) indicates the presence or absence of a header of an extended subheader. The CI field indicates whether the CRC is located after the payload.

The encryption key sequence (EKS) indicates an encryption key sequence number used for encryption when the payload is encrypted. The LEN field indicates the length of the MAC PDU.

CID represents a connection through which the MAC PDU is transmitted as a connection identifier. The CID is used as a MAC layer identifier for data and message transfer between the base station and the terminal, and the CID performs a function of identifying a specific terminal or identifying a specific service between the base station and the terminal. The HCS field is a header check sequence and can be used to detect errors in the header.

3 illustrates an example of an extended subheader that may be used in embodiments of the present invention.

3 is located after the MAC header, which is an additional subheader. The extended subheader includes an 8-bit extended subheader group length field, a 7-bit extended subheader type 1 field, and an extended first subheader having various sizes. It may include a body (Extended Subheader Body 1). In this case, the extended subheader may include one or more extended subheader type fields and one or more extended subheader body fields.

In addition, the size and position of each field in FIG. 3 is not limited to FIG. 3 and may be variously changed. In particular, it can be changed according to user requirements or channel conditions.

4 shows an example of a MAC PDU that includes a subheader and an extended subheader.

4 (a) shows a MAC PDU including a subheader. Referring to FIG. 4A, the MAC PDU includes a grant management header (GMH), a sub header, and a payload.

The admission management header is similar to the MAC header of FIG. In addition, the subheader in the MAC PDU may indicate one of a grant management subheader, a packing subheader, and a fast feedback allocation subheader. In this case, the type of the subheader may be indicated in the type field of the MAC header.

4 (b) shows a MAC PDU including an extended subheader. Referring to Figure 4 (b), GMH is similar to Figure 4 (a). However, the MAC PDU of FIG. 4B includes an extended subheader rather than a general subheader. The extended subheader may include an extended subheader group length field, an extended subheader type field, and an extended subheader body field. In this case, the ESF field of the GMH may indicate an extended subheader group length field.

The extended subheader field in FIG. 4B may use the extended subheader described in FIG. 3. Therefore, the detailed description may refer to FIG. 3.

FIG. 5 is a diagram illustrating a relationship between a connection and a service flow, which may be used in embodiments of the present invention.

In FIG. 5, a connection of the MAC layer is defined to provide a quality of service (QoS) for higher service flows as shown in FIG. 4. Accordingly, the traffic classifier maps the higher service flow with the connection in which QoS parameters are defined. In this case, the scheduler provides appropriate scheduling for the connection in order to provide QoS in the MAC layer. Types of connections defined in the MAC layer include a management connection allocated for each terminal for management of the terminal in the MAC layer, and a transport connection mapped to a service flow for higher service data transmission.

Table 1 below shows the types and functions of connection identifiers.

Referring to Table 1, a ranging CID is used in a ranging process of a terminal and a base station. Basic CID is assigned the same value for both downlink (DL) and uplink (UL). The Primary Management CID is also assigned the same value to both the DL and UL.

The same value is assigned to the DL and UL connections in the transmission CID and the secondary management CID. In addition, for the DL multicast service, the same value is assigned to all terminals on the same channel participating in the connection. When allocating the AAS ranging period, the base station allocates an AAA Initial Ranging CID (AAS Initial Ranging CID) to support AAS.

The base station includes one or more multicast polling groups to obtain bandwidth through polling. The base station may use a multicast polling CID (PID) when polling. Normal mode multicast CID (Normal Mode Multicast CID) is used in DL-MAP to define a burst for transmitting DL broadcast information to a normal mode terminal.

Sleep mode multicast CID (Sleep mode Multicast CID) is used in the DL-MAP to define a burst for transmitting DL broadcast information to the sleep mode terminal. In addition, sleep mode multicast CID may be used in the MOB_TRF-IND message. Fragmentable Broadcast CID (Fragmentable Broadcast CID) is used by the base station to fragment and transmit a management broadcast message. The fragment subheader uses an 11 bit FSN on the connection. The padding bit is used to transmit padding information by the terminal and the base station. Broadcast CID (Broadcast CID) is used to transmit broadcast information to all terminals on the DL.

Hereinafter, resource allocation identifiers (eg, MS IDs) and flow identifiers (Flow IDs) used in preferred embodiments of the present invention will be described.

In order to reduce overhead of a connection identifier (CID) included in a commonly used MAC header, a unique identifier may be allocated to the terminal. That is, instead of the CID used for addressing and service classification of a MAC PDU, a unique flow ID may be used in the terminal.

For example, a connection identifier generally used in a MAC header is a 16-bit long identifier that is unique within a base station, whereas a flow ID used in the present invention is an 8-bit or unique identifier in a terminal. Shorter lengths.

In addition, the base station may allocate radio resources to the terminal for data transmission and reception. That is, the base station may allocate a physical burst to the terminal using a MAP message for allocating resources. In this case, the base station may allocate a resource allocation CID (RACID) unique to the terminal in the base station by using the MAP message. The base station may allocate a terminal identifier (MS ID) as one of the resource allocation connection identifiers. The terminal identifier (MS ID) may be assigned to a size larger than the flow identifier. That is, the base station may use the RACID used for resource allocation in the DL-MAP in a form similar to a general 16-bit CID.

When the base station establishes a service connection with the terminal, the base station allocates a flow identifier to be included in the MAC header when the service data is delivered to the terminal. The terminal may selectively transmit and receive UL / DL data using a resource allocated to the MS ID through DL-MAP or UL-MAP transmitted from the base station. In addition, the base station includes a flow identifier in the MAC header when configuring the MAC PDU, so that the terminal can distinguish the service data for itself and properly transfer to the upper layer.

Hereinafter, a MAC header structure and a MAC PDU format for supporting a resource allocation identifier and / or a flow identifier used in embodiments of the present invention will be described.

6 shows an example of a MAC header structure optimized for unicast connection as an embodiment of the present invention.

Referring to FIG. 6, the MAC header includes a header type (HT) field, an extended subheader field (ESF) field, a flow identifier (Flow ID), and a LEN field. The 1-bit HT field indicates whether the MAC PDU is a general MAC header including a payload or a signaling header transmitted only with a MAC header without a payload for the purpose of transmitting control information.

The ESF indicates whether an additional subheader is present between the MAC header and the payload. The flow identifier may indicate which connection the MAC PDU belongs to. In the embodiment of the present invention, it is assumed to have a size of 4 bits. Of course, the size of the flow identifier can be changed according to the requirements of the user or the channel environment.

The LEN field indicates the size of the MAC PDU to which the MAC header belongs. The size of the LEN field may be expressed in bytes.

When configuring the MAC header with only 2 bytes (16 bits) as shown in FIG. 6, overhead can be reduced as compared with the general MAC header of 6 bytes (48 bits). In this case, the function of the type field and the ESF field included in the MAC header generally used may be performed in the ESF field of the MAC header of FIG. 6. In addition, in an embodiment of the present invention, the flow identifier may further perform functions of a CIC field, an EC field, and an ECS field.

The function of the type field of the general MAC header may also be replaced by another field. For example, if an extended subheader is included in a MAC PDU, the Grant Management Subheader, Packing Subheader, and Fragment Subheader will be defined in the Extended Subheader Type field. Can be.

7 illustrates an example of a MAC PDU structure including an extended subheader according to an embodiment of the present invention.

Referring to FIG. 7, the MAC header uses the MAC header of FIG. 6. In FIG. 7, the ESF field of the MAC header indicates whether an extended subheader is included in a MAC PDU. In FIG. 7, it is assumed that an extended subheader is used.

It is possible to determine whether to use HARQ (Hybrid Automatic Retransmission Requset) in the service connection establishment procedure of the base station and the terminal (or the basic capability negotiation process of the initial network registration procedure of the terminal). In addition, it may be determined whether CRC is used for the MAC PDU.

For example, the BS and the UE may determine whether to use a CRC field, an encryption control (EC) field, and an encryption key sequence (EKS) field in a service connection establishment procedure. That is, in the process of allocating the flow identifier when the service connection is generated, the UE and the base station may determine the CRC information of the corresponding service flow in the MAC PDU as the flow identifier. Accordingly, the terminal can confirm the presence of the CRC by checking the flow identifier included in the MAC header.

Functions of EC and EKS related to data encryption may also be set when the UE generates a service flow (or a basic capability negotiation process). That is, the base station can determine the encryption of the MAC payload by assigning to the flow identifier whether or not the security association determined when generating the service flow with the terminal. Accordingly, the terminal may obtain information on the encryption and the encryption key sequence through the corresponding security association by checking the flow identifier of the MAC header.

In addition, in embodiments of the present invention, HARQ may be configured to be applied in a service connection establishment process (or initial network registration process). Since error checking and error recovery are performed on the MAC PDU through HARQ processing, there is no need to perform additional error checking on the MAC header using the header check sequence (HCS) at the MAC layer.

Therefore, in the generic MAC header structure, a header type (HT) indicating a header type, a field indicating whether a subheader is included (ESF), and a flow ID serving as a connection identifier for a service flow ) And the other fields except the LEN (Length) field indicating the size of the MAC PDU may configure the MAC header in a omitted form.

8 is a diagram illustrating an example of a MAC PDU structure for multicast and broadcast service connection according to another embodiment of the present invention.

8 illustrates a case in which the size of the flow identifier is 8 bits or more. FIG. 7 illustrates a 2-byte MAC header structure, in which a flow identifier for a service flow is represented by 4 bits. However, a 4-bit flow identifier is not sufficient to classify each MBS service flow in each MBS channel in the MAC layer.

Accordingly, an 8-bit flow identifier may be used for the MBS connection unlike the unicast connection. In addition, since HARQ is not applied to the MBS connection, the base station or the terminal may add the HCS for header error checking to the MAC PDU.

However, different MAC header structures in the unicast connection (FIGS. 6 and 7) and the multicast connection (FIG. 8) are preferably distinguished when composing the MAP message. In addition, resource allocation for physical burst transmission in the unicast service and resource allocation for physical burst transmission in the MBS service may be clearly distinguished. Therefore, when constructing a MAP message for resource allocation, it is desirable to clearly distinguish between unicast connection and MBS connection.

9 illustrates another example of a MAC PDU structure for MBS connection according to another embodiment of the present invention.

9 is basically similar to the MAC PDU structure of FIG. Referring to FIG. 9, the MAC header (GMH) includes an HT field, an ESF field, a flow identifier, and a LEN field. In this case, the flow identifier may have a fixed value to indicate the MBS flow. In addition, the ESF field may indicate that the extended subheader is included in the MAC PDU.

The extended subheader may include an extended subheader group length field, an extended subheader type field, and an extended subheader body. In this case, the extended subheader type field may indicate an MBS flow ID. The extended subheader body may include an MBS flow identifier.

FIG. 10 illustrates another example of a MAC PDU structure for MSB connection according to another embodiment of the present invention.

The MAC header of FIG. 10 is basically similar in structure to the MAC header of FIG. However, the MAC header of FIG. 10 has a structure in which an HCS field for error detection of the MAC header is further added. Since HARQ may not be applied to the MBS connection, the addition of the HCS is not necessarily required. However, an HCS field may be additionally added for error detection of the MAC header.

Table 2 below shows mapping relationships between CIDs, resource allocation connection identifiers (RACIDs), and flow identifiers.

Classification The legacy CID RACID (x bits) Flow ID (y bits) Random Access ID Ranging CID Ranging RACID -Random access channel: 0x00 -Dedicated HO ranging channel: MSID or HO multicast ID -Random access channel: No flow ID -Dedicated channel for initial ranging request message: Fixed value (e.g. 0b0000) -Dedicated channel for HO ranging request message: Basic flow ID can be used Unicast ID Basic CID MSID Fixed value (Basic flow ID is defined) Primary CID MSID Fixed value (Primary flow ID may be defined) Or may not be defined Transport CID MSID Dynamic allocation (0b0001 0b1111) Multicast ID Multicast CID Multicast RACID * MBS LCID can be defined larger (e.g. 8bits) than unicast LCID. In this case, MAC header of MBS flow has different format from that of unicast flow. Broadcast ID Broadcast CID Broadcast RACID -Broadcast control channel: 0xff -Paging channel: Paging RACID per paging group (e.g. Large paging group, small paging group) Fixed value (e.g. 0b1111) Or may not be defined

Referring to Table 2, a resource allocation CID (RACID) for resource allocation in a random access channel may use a fixed value. In this case, since the uplink signal transmitted on the random access channel is transmitted in the form of a physical sequence rather than the MAC PDU, the flow identifier may not be used.

In addition, when resources of the random access channel are not allocated in the general uplink map, and resources of the random access channel are allocated in the broadcast control channel (BCH) transmitted in a certain period (Superframe unit), RACID is omitted. Can be.

In addition, after the terminal transmits the initial ranging sequence to the base station, the terminal may be allocated a dedicated uplink resource for transmitting the ranging request message from the base station. In this case, the RACID may use a fixed value (eg, 0x00), and the flow identifier may have a fixed value (eg, 0b0000).

Alternatively, a resource allocation identifier and a flow identifier composed of a combination of an initial ranging sequence and a random access channel may be applied. In this case, the random access resource allocation identifier may be assigned according to the ranging sequence selected by the terminal. The terminal may allocate resource of the ranging response message through the random access resource allocation identifier corresponding to the ranging sequence transmitted by the terminal. You can check.

In addition, when the random access resource allocation identifier is determined in combination with the random access channel, the terminal is automatically assigned a random access resource allocation identifier by the random ranging sequence and the uplink random access channel number transmitted by the terminal, It may be determined whether a ranging response message for the ranging sequence transmitted by the UE may be received through the random access resource allocation identifier of the downlink map. The terminal may obtain information on the random access resource allocation identifier through a broadcast control channel (BCH) transmitted from the base station.

In addition, the base station may allocate resources necessary for handover ranging to the terminal exclusively during handover. The RACID may be pre-assigned from the serving base station by the terminal in the process of handover message exchange with the serving base station. Accordingly, the MS ID which is the unicast resource allocation identifier of the terminal may be used as the resource allocation connection identifier. In addition, multiple handover terminals may perform handover ranging by using the same resource. At this time, the base station may use a handover multicast identifier (HO Multicast ID) as the RACID. In this case, the handover terminals transmit different handover ranging codes, thereby allowing the target base station to identify each handover terminal.

Referring to Table 2 again, the unicast identifier used in the unicast channel will be described. In a legacy system, a basic CID, a primary CID, and a transport CID are used as unicast identifiers. In this case, the general system performs both resource allocation and connection for service flow with the same connection identifier.

In the embodiments of the present invention, a unique terminal identifier (MS ID) may be used at a base station for resource allocation, and a flow identifier may be used to identify a service flow as a unicast identifier. However, the flow identifier may be assigned a fixed value or a dynamic value according to the purpose of use.

Referring back to Table 2, in a general system as a multicast identifier, resource allocation and service flow can be identified as a multicast CID. However, in the embodiments of the present invention, a multicast resource allocation connection identifier (Multicast RACID) is used for resource allocation, and an MBS flow identifier having a size larger than a flow identifier used in a unicast connection is used to identify a service flow. Can be used. In this case, the MAC header for MBS connection preferably takes a different structure from the MAC header for unicast connection.

Referring back to Table 2, in a general system as a broadcast identifier, resource allocation and service flow may be identified as a broadcast CID. However, embodiments of the present invention use the broadcast RACID for resource allocation. In this case, a fixed value (Oxff) may be used for the broadcast control channel as the RACID, and a different paging RACID per paging group may be used for the paging channel.

For example, a small paging group having a smaller size than a paging group used in a general system may be defined. In this case, the small paging group RACID for resource allocation to the small paging group may be used. In addition, a paging group having an area larger than the small paging group may be defined as a large paging group, and may use a large paging group RACID.

In addition, in the embodiments of the present invention, a fixed value (eg, 0b1111) of 4 bits may be used as a flow identifier for a service flow used in a broadcast channel.

FIG. 11 is a diagram illustrating a mapping relationship between a resource allocation connection identifier and an MBS flow identifier for an MBS service connection according to another embodiment of the present invention.

In another embodiment of the present invention, a resource allocation connection identifier (RACID) and an MBS flow identifier (MBS Flow ID) for the MBS service may be variously defined according to the MBS service channel.

For example, when the MBS service channel and the RACID are mapped 1: 1, the MBS flow identifier may be defined with a fixed size. In addition, when the MBS service channel and the RACID are mapped to N: 1, the MBS service channel may be mapped to the MBS flow identifier at 1: 1.

In this case, in order to receive a specific MBS service channel, it is preferable that a terminal is allocated a RACID and a flow identifier for a specific MBS service channel during a multicast and broadcast service (MBS) connection setup process. Accordingly, the terminal can obtain resource allocation information for the MBS channel to be received from the base station by using the RACID according to each MBS.

In embodiments of the present invention, the size of the flow identifier may be limitedly defined (eg, 4 bit Flow ID). In this case, even if the MBS channel and the RACID are set to N: 1, a plurality of RACIDs may be used for MBS data transmission between the terminal and the base station. In this case, the terminal may obtain both the RACID and the MBS flow identifier information for the MBS service channels that can be received from the base station when establishing the MBS connection.

Referring to FIG. 11, a case in which the UE receives MBS channels A, B and C (MBS channels #A, #B and #C) will be described.

When the UE establishes the MBS connection from the base station, the UE receives the MBS RACID # 1 and the MBS RACID # 2 for resource allocation, and the MBS Flow ID (MBS Flow ID # 0; MBS Flow ID # 0 and # 1) for each MBS RACID. ) Can be assigned. In this case, the UE may identify the MBS service flow by the RACID even if the same MBS flow identifier 0 is allocated to the MBS channels A and B. FIG. Therefore, the terminal can selectively receive the MBS.

As illustrated in FIG. 11, the terminal and the base station may configure mapping of the MBS channel, the RACID, and the MBS flow identifier to 1: 1: 1 or N: 1: N, and the base station may configure the plurality of RACIDs for the MBS service. Can be given to Accordingly, the terminal may distinguish each MBS channel by using a 4-bit flow identifier. That is, there is an advantage that allows the MBS connection to configure the same MAC header structure as the unicast connection.

However, whether to selectively add the HCS for detecting the MAC header error to the MAC header for the MBS connection may be determined through negotiation between the terminal and the base station or by agreement in advance.

The RACID for the broadcast control connection can generally be fixed to a value such as 0xFF. However, the base station may assign different RACIDs to the terminal according to specific control purposes such as paging for the idle mode terminal. At this time, the base station may allocate a different paging RACID (Paging RACID) to the terminal for each paging group in order to reduce the decoding burden of the terminal for the paging information. Therefore, the terminal can selectively save only paging information according to the paging group to which it belongs, thereby saving available resources of the terminal. That is, the flow identifier for the paging control information may be set to a fixed value or not used by omitting the MAC header.

12 is a diagram illustrating a method of allocating a MAC header and a MAC PDU for downlink data transmission according to another embodiment of the present invention.

Referring to FIG. 12, it can be seen that a flow identifier (FID) for delivering and distinguishing a MAC PDU is included in a MAC header. In this case, the MAC PDU may take a concatenation structure including one or more MAC headers. In addition, a resource allocation connection identifier (RACID) for resource allocation may be included in a DL-MAP message to indicate a downlink burst to which a corresponding MAC PDU is transmitted.

12 illustrates the case of downlink, the technical spirit of the present invention may be transmitted even in the case of uplink. In the case of uplink, the base station transmits an uplink map including the RACID to the terminal, and the terminal may transmit uplink data to the base station through the uplink resource region indicated by the RACID. In this case, the terminal may transmit a MAC header including a flow identifier (FID) allocated when establishing the service connection to the base station.

13 shows a method of transmitting a MAC PDU as another embodiment of the present invention.

Referring to FIG. 13, the terminal and the base station may perform service connection establishment (or a basic capability negotiation process of an initial network registration procedure of the terminal) (S1301).

In step S1301, the base station may allocate a flow identifier for identifying a service flow and / or a resource allocation connection identifier (RACID) for resource allocation to the terminal. In this case, the flow identifier is an identifier unique to the terminal in the terminal, and the RACID is preferably an identifier unique to the base station in the base station. In addition, the service flow may be a unicast service flow or an MBS flow.

The base station may configure the MAC header by using the flow identifier and / or RACID assigned to the terminal (S1302).

Thereafter, as the communication is performed, the base station may include the MAC header in the MAC PDU and transmit it to the terminal (S1303).

The terminal may selectively receive and / or transmit data using the flow identifier assigned from the base station in step S1201 (S1304).

The invention can be embodied in other specific forms without departing from the spirit and essential features of the invention. Accordingly, the above detailed description should not be construed 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. It is also possible to form embodiments by combining claims that do not have an explicit citation in the claims or to include them as new claims by post-application correction.

Claims

In the method of transmitting a medium access control protocol data unit (MAC PDU),

Allocating a unique flow identifier within the terminal to the terminal when establishing a service connection;

Constructing a MAC header containing the flow identifier; And

Transmitting the MAC PDU including the MAC header,

The flow identifier is used for addressing and service classification of the MAC PDU.

The method of claim 1,

Transmitting a map (MAP) message that includes a resource allocation connection identifier (RACID) for resource allocation;

The resource allocation connection identifier has a size larger than the flow identifier MAC PDU transmission method.

The method of claim 2,

The service connection is a multicast and broadcast service connection,

And the flow identifier and the resource allocation connection identifier are allocated to the terminal when the multicast and broadcast service connection is established.

The method of claim 1,

The MAC header further includes only a header type field, a subheader field indicating whether a subheader included in the MAC PDU is present, and a field indicating a size of the MAC PDU,

And the MAC header is used for unicast connection.

The method of claim 4, wherein

The MAC PDU further comprises an extended subheader including an extended subheader group length field, an extended subheader type field, and an extended subheader body.

The method of claim 4, wherein

The flow identifier is

The MAC PDU transmission method further comprises information about a cyclic redundancy check field, an encryption control field, and an encryption key sequence.

The method of claim 1,

The MAC header further includes only a header type field, a subheader field indicating whether a subheader included in the MAC PDU is present, and a field indicating a size of the MAC PDU.

The MAC header is used to transmit a multicast broadcast service (MBS) MAC PDU, characterized in that.

The method of claim 7, wherein

The MAC header further includes a header check sequence for error detection of the MAC header,

And the flow identifier has a fixed value for indicating a multicast broadcast service (MBS) connection.

The method of claim 7, wherein

The flow identifier has a fixed value for indicating an MBS flow.

The extended subheader type field indicates the MBS flow ID included in the extended subheader body,

The extended subheader body field includes the MBS flow identifier.

Receiving a unique flow identifier assigned to a terminal when establishing a service connection from a base station;

Selectively transmitting or receiving data using the flow identifier;

Constructing a MAC header containing the flow identifier; And

And delivering the MAC PDU including the MAC header to a higher layer.

Receiving an uplink map message including a resource allocation connection identifier indicating an uplink resource region from the base station;

Configuring an uplink MAC header including the flow identifier; And

And transmitting the MAC PDU including the uplink MAC header to the base station through the uplink resource region.

The method of claim 11,

And the MAC header is used for unicast connection.

The method of claim 12,

The flow identifier is