KR101477280B1 - Control Information Transmission and Receiving in Packet based Mobile Communication System - Google Patents

Abstract

The present invention relates to a control information transmission method capable of transmitting control information required between a base station and a medium access control (MAC) layer of a mobile terminal in a packet-based mobile communication system using control channel blocks while minimizing consumption of control channel blocks, A method for transmitting control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, the method comprising the steps of: (a) Configuring a control channel block including identification information and the control information for controlling the terminal; And (b) channel-coding and transmitting the control channel block to the terminal.

Packet, LTE, mobile communication, MAC, wireless, resource, block, allocation, control information, transmission

Description

Technical Field [0001] The present invention relates to a control information transmission method and a packet reception method in a packet-based mobile communication system,

The present invention relates to a method of transmitting control information in a packet-based mobile communication system and a receiving method thereof, and more particularly, to a method of controlling a medium access control (MAC) of a base station and a mobile station in a next- To a method of transmitting control information and a method of receiving the control information, which can transmit control information required between layers by using a control channel block while minimizing consumption of the control channel block.

The present invention was derived from research carried out as part of the IT new growth engine core technology development project of the Ministry of Information and Communication and the Korea Information Society Agency [assignment number: 2005-S-404-13, title: 3G Evolution Wireless Transmission Technology Development ].

The 3rd Generation Partnership Project (3GPP), an asynchronous mobile communication standardization organization, is carrying out LTE (Long Term Evolution) standardization activities for the development of the next generation mobile communication system standard. The next generation packet based mobile communication system uses a frequency division duplex (FDD) wireless transmission scheme, an orthogonal frequency division multiple access (OFDMA) scheme is used for a downlink, a single carrier frequency division A single-carrier frequency division multiple access (SC-FDMA) scheme is used.

A typical mobile communication system includes a base station constituting a cell and a mobile station used by a user, and a plurality of mobile terminals transmit and receive packet data to and from a base station via a wireless channel.

FIG. 1 is a diagram illustrating a configuration of a general packet-based mobile communication system. In FIG. 1, only the base station 10 and the mobile terminal 20 are shown.

The base station 10 and the mobile terminal 20 transmit and receive data and control information through a radio channel divided into a downlink and an uplink. The downlink data is input to the downlink buffer 11. The radio resources are allocated to the mobile stations by the downlink scheduler 12 and the data input to the downlink buffer 11 is transmitted to the mobile stations through the radio resources allocated by the downlink scheduler 12 . Since the radio resources of the packet-based mobile communication system are dynamically allocated by the scheduler, a physical downlink control channel (PDSCH) is used as a data channel through a physical downlink control channel (PDCCH) The control information required to demodulate the downlink shared channel) is transmitted.

The process of transmitting uplink data will be described as follows. A radio resource for transmitting uplink data is allocated by an uplink scheduler 13 located in a base station. Then, the mobile station constructs a Physical Uplink Shared Channel (PUSCH), which is an uplink data channel, by using the uplink radio resource information reported on the physical downlink control channel (PDCCH) And transmits the data input to the uplink buffer 21. A physical uplink control channel (PUCCH), which is an uplink control channel, is used for transmission of uplink buffer status information and downlink retransmission information.

For the description of the present invention, a physical channel used in a packet-based mobile communication system will be briefly described. The downlink channel associated with the transmission of the data is as follows.

A Physical Downlink Shared Channel (PDSCH) is a physical channel for transmitting downlink data. The physical downlink shared channel is allocated and transmitted to a radio resource block (RB) shown in FIG. Generally, a plurality of resource blocks may be allocated for one mobile terminal by a scheduler of a base station. 2, when the physical downlink control channel (PDCCH) region 34 is used in a small amount in the radio resource block, the remaining OFDM symbols 32 may be allocated to the PDCCH region 34. [ That is, if the use of the control channel (PDCCH) block is minimized, the amount of data to be transmitted through one radio resource block can be increased accordingly.

A physical downlink control channel (PDCCH) is a physical channel for transmitting control signaling required for data reception to a mobile terminal. The physical downlink control channel is allocated and transmitted to the PDCCH block 33 in Fig. The physical downlink control channel includes control information required for reception of a physical downlink shared channel (PDSCH) and control information for a physical uplink shared channel (PUSCH). The control information for the physical uplink shared channel is transmitted through the physical downlink control channel because the uplink packet scheduler managing the uplink transmission / reception of the packet mobile communication system uses a centralized method in which the base station is located. In other words, the uplink packet scheduler located at the base station manages the uplink radio resources of all the mobile stations under the management of the base station, and performs resource allocation and collection.

Next, an uplink channel related to data transmission is as follows.

A physical uplink shared channel (PUSCH) is a physical channel for transmitting uplink data, and is similar to a PDSCH. The control information associated with the physical uplink shared channel is transmitted on the physical downlink control channel (PDCCH) at the base station.

A physical uplink control channel (PUCCH) is a physical channel for transmitting control information from a mobile station to a base station, and uses a radio resource separate from the PUSCH. The control information included in the physical uplink control channel includes a downlink channel state, downlink retransmission information, and uplink buffer state information.

FIG. 2 is a diagram illustrating a downlink radio channel structure of a general packet-based mobile communication system, and illustrates a radio channel structure of an LTE system under discussion in 3GPP.

A packet-based mobile communication system transmits data in parallel using a plurality of radio carriers for communication, and describes a packet mobile communication system using an OFDMA scheme.

The packet-based mobile communication system transmits data using a plurality of subcarriers, and manages subcarriers in a system bandwidth (for example, 20 MHz) by grouping subcarrier groups 31 on the frequency axis. And the OFDM symbols 32 are managed in units of a transmission time interval (TTI) (for example, 1 msec) on the time axis. For example, one TTI may include 14 OFDM symbols depending on the time length of the OFDM symbol. Accordingly, the radio resources are divided into resource blocks (RBs). One resource block (RB) is a resource block (RB) that groups an OFDM symbol with a subcarrier group (31) It is an allocation unit.

The resource block (RB) is obtained by dividing a radio resource by a predetermined size so that the scheduler of the base station can easily allocate data. For example, the size of the resource block (RB) is a bundle of symbols of "12 subcarriers × TTI (1 msec)". The amount of data information that can be allocated to a resource block depends on an adaptive modulation scheme, which varies depending on the type of modulation scheme applied to the symbol (for example, QPSK, 16QAM, 64QAM). Also, when data is allocated to a resource block, a modulation technique necessary for channel coding and wireless communication is used, so that the amount of information of a resource block is variable. The uplink of the packet-based mobile communication system uses the SC-FDMA scheme, but the features related to the present invention are the same as those described with reference to FIG. 2, so that the description of the uplink radio channel structure is omitted.

From the viewpoint of radio channel operation, the base station (transmitting unit) must transmit control information so that the mobile terminal (receiving unit) can demodulate the data, and uses a Physical Downlink Control Channel (PDCCH) channel for this purpose. The PDCCH channel uses subcarriers of the entire system bandwidth as the frequency axis and a maximum of three OFDM symbols as the time axis in the TTI. Therefore, the PDCCH channel can use up to three symbols in the resource block (RB) as the PDCCH region. The PDCCH region distributed in the entire system bandwidth is divided into a plurality of PDCCH resource blocks 33 in order to transmit control information necessary for each mobile terminal. Referring to FIG. 2, one PDCCH resource block is composed of three OFDM symbols belonging to two resource blocks (RB), and "2 resource blocks 占 14 subcarriers 占 3 OFDM symbols = 84 symbols ≪ / RTI >

In a packet-based mobile communication system, when a relatively small-sized control information is allocated to a data channel (PDSCH) and transmitted, a data channel (PDSCH) is wasted and a control channel (PDCCH) is also consumed. In particular, the control information required between the base station and the MAC (Medium Access Control) layer of the mobile terminal has a small size of 1 to 10 bits. In order to reduce the inefficient operation caused by allocating the control information of a small size to the data channel, there is a need for a method of directly assigning small-sized control information to the control channel (PDCCH) and transmitting the control information. Further, in order to transmit various types of control information through a control channel (PDCCH), a flag having a predetermined size is required to distinguish control information. This causes a problem that control channel (PDCCH) resources are consumed. do. Therefore, there is a need for a technique for transmitting control information on a control channel (PDCCH) while minimizing consumption of control channel resources.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above problems of the related art, and it is an object of the present invention to provide a method and apparatus for controlling a control channel, And a method of receiving the control information and a method of receiving the control information.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to another aspect of the present invention, there is provided a method for transmitting control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, the method comprising the steps of: (a) Comprising the steps of: constructing a control channel block including identification information for identifying the terminal and control information for controlling the terminal; And (b) channel-coding and transmitting the control channel block to the terminal.

According to another aspect of the present invention, there is provided a method for transmitting control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, the method comprising the steps of: (a) Wherein identification information for identifying control information to be transmitted to the terminal is allocated to a specific field of a control information area constituting the control channel block, and control information for controlling the terminal is stored in the control information area, Allocating a control channel block to the control channel block; And (b) channel-coding and transmitting the control channel block to the terminal.

Preferably, the control channel block includes error correction code (CRC) information, and the error correction code information is masked using the identifier of the specific terminal so that only a specific terminal can decode the control channel block.

Preferably, according to the present invention, a value of a transport block (TB) field indicating size information of a resource block included in the control information area is set to '0', and control information transmitted to the mobile station As identification information.

Preferably, the present invention further comprises: allocating a number other than a number indicating the number of resource blocks effectively allocated in the resource block location information field, and identifying the control information transmitted to the terminal without the flag field Use as information.

Preferably, the control information for controlling the terminal is medium access control (MAC) information such as timing adjustment information or discontinuous transmission / reception information for low power control.

According to another aspect of the present invention, there is provided a method for receiving control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, the method comprising the steps of: (a) Receiving a channel block; (b) demodulating the received control channel block; (c) identifying the type of the control information by checking identification information for identifying control information transmitted from the channel-demodulated control channel block to the terminal; And (d) acquiring the control information included in the control information area of the control channel block after recognizing the type of the control information.

According to another aspect of the present invention, there is provided a method for receiving control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, the method comprising: (a) Receiving a control channel block that does not include a field; (b) demodulating the received control channel block; (c) recognizing the type of the control information by checking identification information for identifying control information transmitted from the specific field of the control information area defined in the channel-demodulated control channel block to the terminal; And (d) acquiring the control information included in the control information area of the control channel block after recognizing the type of the control information.

Preferably, according to the present invention, when a value of a transport block (TB) field indicating size information of a resource block included in the control information area is assigned as '0' It is recognized that it is the control information to be used.

Preferably, in the present invention, when a number other than a number indicating the number of resource blocks effectively allocated in the resource block position information field is allocated, information included in the control channel block is transmitted as control information .

According to the present invention as described above, the base station directly transmits the control information required by the MAC layer through the control channel, thereby minimizing waste of radio resources of the data channel. Further, according to the present invention, a value that is not generally used among modulation and demodulation information of a data channel (for example, a value of a data size of '0' is assigned to a transmission block (TB) field) without using a flag field By dividing the control information in the control channel block, the waste of the radio resources of the control channel can be minimized.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In general, a control channel (PDCCH) is a channel used to transmit modulation and demodulation information of downlink and uplink data channels (PDSCH, PUSCH) to a mobile terminal. In the present invention, a method for efficiently transmitting control information (for example, control information required in the MAC layer) other than modulation / demodulation information through a control channel is presented. Herein, the control information refers to control information required between the base station and the MAC layer of the mobile terminal, and small size (1 to 10 bits) of control information required between the layers. In the following description, MAC control information is described as an example, but the present invention is not limited thereto.

3 is a diagram for explaining a configuration of a control channel block and a method of transmitting control information according to a preferred embodiment of the present invention. In FIG. 3, the control channel structure is a schematic view of a structure of a PDCCH channel generally used in a packet-based mobile communication system, and a control channel structure for the present invention is added.

The physical downlink control channel (PDCCH) area 101 is composed of a plurality of control channel blocks such as CB1 to CBn, and each control channel block CB includes uplink or downlink And control information of the data channel. 3, the control channel block CB 1 includes downlink (DL) data channel information of the mobile station UE 1, and the control channel block CB 2 includes uplink (UL) data channel information.

The configuration information of the general control channel block (CB) defined in LTE includes the following information.

First, the control channel block includes modulation / demodulation information of a downlink (DL) or uplink (UL) data channel. Modulation and demodulation information of a data channel includes size information (e.g., payload size = 20 bits) of a radio resource block, location information (e.g., RB 5 and RB 6) of a radio resource block, channel coding information (For example, turbo coding scheme and modulation data rate 1/3), adaptive modulation information (e.g., QPSK, 16QAM, 64QAM), antenna information (e.g., information for supporting MIMO operation) , And retransmission information (e.g., information for supporting a hybrid retransmission (HARQ) operation).

Next, there is CRC (16 bits) information, which is an error correction code of the control channel block, as configuration information of a general control channel block (CB) defined in LTE. The CRC is masked with a mobile terminal identifier (C-RNTI). Accordingly, no CRC error occurs when the designated mobile station demodulates the control channel block, so that only the designated mobile station can demodulate the control information. Therefore, as shown in FIG. 3, when configuring the uplink or downlink transmission information in the control channel block in the base station, a control channel block is configured including data channel information and CRC information.

Referring to FIG. 3, a control channel block may generally include a flag field 103, which is information added to display various types of control information.

3, the control channel block CB 1 includes a flag field 103, downlink data channel information 104 of the mobile station UE 1, and CRC information 105. Also, the control channel block CB 2 includes a flag field, uplink (UL) data channel information of the mobile station UE 2, and CRC information.

When the UE receives and demodulates the control channel, it can distinguish the uplink information or the downlink by analyzing the flag field. However, the use of the flag field separately requires the use of flags of a certain size (for example, 1 to 4 bits) in all the control channels, thereby wasting radio resources. Particularly, a control channel transmitting data channel modulation / demodulation information other than a channel for transmitting separate MAC control information must always keep flags of the same size, thereby wasting wireless resources.

In order to solve such a problem, the present invention proposes to use the value of a field which is not commonly used in modulation and demodulation information of a data channel as an identifier for distinguishing the type of a control channel.

For example, in a field for displaying size information of a resource block, a value of a data size of '0' (for example, a value of a Transport Block (TB) field = 0) I never do that. Therefore, it is possible to assign a specific value (e.g., a value of '0') to the transport block (TB) field 107 to distinguish the control information format. Accordingly, when the value of the transport block field is '0', the MS recognizes that the following information is MAC control information for controlling the MS.

Referring to FIG. 3, the control channel block CB3 106 does not include a separate flag field, but consists only of the control information field and the CRC information 110 of 16 bits. The control information area is composed of a 4-bit transport block (TB) field 107, a 2-bit sub-index field 108 and an 8-bit specific control information field 109.

Accordingly, when the MAC control information is transmitted through the control channel block, the base station sets the TB field 107 to '0' to indicate that the following control information is MAC control information, And assigns MAC control information to the MAC control information.

The terminal demodulates the control channel block, recognizes that the control information is MAC control information when the value of the transmission block field is '0', and uses the MAC control information allocated to the specific control information field, .

Meanwhile, the following method may be used as a method for indicating MAC control information without using a separate flag field.

Normally, the 10-MHz bandwidth system uses up to 50 data resource blocks, so that the resource block location information field is indicated as 51 instead of the number of valid resource blocks, thereby indicating that the MAC control information is not the data channel modulation / demodulation information. In other words, when transmitting the MAC control information through the control channel block, the base station transmits a number other than a number, which means the number of the resource blocks effectively allocated to display the control information included in the control channel block, Information field. If the number of resource blocks allocated to the resource block location information field is not the number of resource blocks to which the number of resource blocks is effectively allocated, the terminal recognizes that the control information included below is MAC control information, Control is performed.

4 is a diagram illustrating a configuration of MAC control information according to an embodiment of the present invention.

The overall size of the control channel (PDCCH) may be variable. As shown in FIG. 4, the detailed information of the control channel block includes a transport block (TB) field indicating a resource block size information, a sub index field, a specific control information (control information payload) field And a CRC field.

A Transport Block (TB) field is a field indicating the size of data that can be allocated to the associated data channel. By assigning a specific value (for example, '0') to this transport block field, it is possible to indicate that the information included in the control channel block is MAC control information. The size of the transport block (TB) field uses the same size as the transport block (TB) field used in a general control channel (PDCCH).

The Sub Index field is a field for identifying the format of the MAC control information. It is possible to display a certain kind of MAC control information according to the size of the sub-index.

The specific control information (control information payload) field is a field containing detailed information of each MAC control information divided according to the sub index. If the MAC control information is timing adjustment advance (TA) control information, the terminal can display information related to a channel to be transmitted on the uplink, and stores a value (index) of a random access preamble . In addition, when the MAC control information is discontinuous reception (DRX) control information for a low power operation, the DRX mode and the DRX period to be changed by the UE may be included. If the terminal changes from a short cycle DRX cycle to a long cycle DRX or vice versa, the base station can direct the state change to the control channel in this format.

Meanwhile, the method of the present invention as described above can be written in a computer program. And the code and code segments constituting the program can be easily deduced by a computer programmer in the field. In addition, the created program is stored in a computer-readable recording medium (information storage medium), and is read and executed by a computer to implement the method of the present invention. And the recording medium includes all types of recording media readable by a computer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

1 schematically illustrates a general packet-based mobile communication system,

2 is a diagram illustrating a structure of a downlink radio channel in a packet-based mobile communication system;

3 is a diagram for explaining a structure of a control channel block according to an embodiment of the present invention;

4 is a diagram for explaining a structure of a control channel block according to each MAC control information according to an embodiment of the present invention.

Claims (16)

delete delete delete A method for transmitting control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, (a) allocating necessary MAC control information between a base station and a MAC layer of the MS in a first area of a control channel block; (b) displaying in the second area of the control channel block, information indicating that the MAC control information is allocated to the first area of the control channel block; And (c) channel coding the control channel block and transmitting it to the terminal / RTI > And the second area includes one field of a plurality of fields including modulation and demodulation information of a data channel in the control channel block. 5. The method of claim 4, Wherein the control channel block includes error correction code (CRC) information and the error correction code information is masked using the identifier of the specific terminal so that only a specific terminal can decode the control channel block. Transmission method. 5. The method of claim 4, Wherein the second area is a transport block (TB) field indicating size information of a resource block, Wherein the step of displaying comprises the step of assigning a value of the transport block (TB) field to '0'. 5. The method of claim 4, Wherein the second area is a location information field indicating a location of a resource block, Wherein the step of displaying comprises the step of assigning a number other than a number indicating the number of resource blocks effectively allocated to the position information field. 5. The method of claim 4, Wherein the MAC control information includes timing adjustment information or discontinuous transmission / reception information for low power control. delete delete delete A method for receiving control information for controlling a terminal in a packet based mobile communication system including an uplink and a downlink scheduler, (a) receiving a control channel block not including a flag field from a base station through a control channel; (b) demodulating the received control channel block; (c) recognizing from the second region of the demodulated control channel block that the information of the first region of the control channel block is required MAC control information between the base station and the MAC layer of the terminal; And (d) acquiring MAC control information included in a first area of the control channel block / RTI > Wherein the second area includes one of a plurality of fields including modulation and demodulation information of a data channel in the control channel block. 13. The method of claim 12, Wherein the control channel block includes error correction code (CRC) information and the error correction code information is masked using the identifier of the specific terminal so that only a specific terminal can decode the control channel block. Receiving method. 13. The method of claim 12, Wherein the second region includes a transport block (TB) field indicating size information of a resource block, And if the value of the transport block field is '0', the information of the first area of the control channel block is the MAC control information. 13. The method of claim 12, Wherein the second area includes a location information field indicating a location of a resource block, Wherein when a number other than a number indicating a number of resource blocks effectively allocated in the position information field is allocated, information indicating a first region of the control channel block is the MAC control information. Way. 13. The method of claim 12, Wherein the MAC control information includes timing adjustment information or discontinuous transmission / reception information for low power control.

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