JP5457486B2 - ACK / NACK channel resource allocation and signaling method and apparatus in wireless communication system - Google Patents

Description

  The present invention relates to a radio communication system, and in particular, an Acknowledgement / Negative Acknowledgment (hereinafter referred to as “ACK / NACK”) for a Hybrid Automatic Repeat reQuest (hereinafter referred to as “HARQ”). The present invention relates to a method and an apparatus for transmitting and receiving.

  There are two main error control methods for data transmission systems: FEC (Forward Error Correction) and ARQ (Automatic Repeat reQuest). The FEC system attempts to correct errors in received data. If error correction is successful, correct data is decoded. If error correction fails, incorrect data is provided to the user or the data is lost. In an ARQ system, when an error is detected from received data, a transmitter transmits data using an FEC code with a good error correction capability, and the receiver requests the transmitter to retransmit.

  FEC has a relatively low efficiency in a good channel environment, and the system reliability decreases when error correction fails. On the other hand, ARQ has the advantage of efficient transmission with high reliability and low redundancy of the system, but the reliability of the system is greatly reduced because frequent retransmission is required in a bad channel environment. To do. In order to overcome these disadvantages, HARQ is proposed by combining FEC and ARQ in an appropriate manner.

  HARQ is a scheme for attempting error correction of received encoded data (HARQ packet). Whether to request retransmission of the HARQ packet is determined from a simple error detection code such as CRC (Cyclic Redundancy Check). After determining whether or not there is an error in the received HARQ packet, the receiver feeds back ACK or NACK to the transmitter. With this ACK or NACK, the transmitter retransmits the HARQ packet or transmits a new HARQ packet.

  The receiver uses appropriate radio resources for ACK / NACK transmission. The ACK / NACK is transmitted through several subcarriers in an OFDM (Orthogonal Frequency Division Multiplexing) wireless communication system, and is transmitted through a predetermined code channel in a WCDMA (Wideband Code Division Multiple Access) system. Generally, a HARQ packet is transmitted simultaneously to a plurality of users for one transmission time interval (hereinafter referred to as “TTI”). Therefore, ACK / NACK is also transmitted simultaneously for the HARQ packet.

  When the base station (Node B) allocates a downlink data channel to a user terminal (UE), the UE allocates a control channel resource for transmitting ACK / NACK to the downlink data channel. In the case of uplink data transmission, the Node B receives the uplink packet data from the UE through the uplink data channel and then transmits ACK / NACK for the packet data using the resources promised between the Node B and the UE. To do.

  In general, limited resources are available in the system, and the system resources must be allocated appropriately for channels including data channels and ACK / NACK channels (ACKCH). Therefore, it is important to allocate the necessary amount of resources for the TTI given to the ACKCH. In order to explain this resource allocation, as an example, FIG. 1 shows an EUTRA (Enhanced Universal Terrestrial Radio Access) -OFDM downlink frame structure. UTRA is the next generation mobile communication standard of 3GPP (3rd Generation Partnership Project).

  Referring to FIG. 1, the system bandwidth 101 is 10 MHz, and all 50 resource blocks (RB) 102 are defined in the system bandwidth 101. Each RB 102 includes 12 subcarriers 103, and a 1 ms TTI 105 has 14 OFDM symbol intervals 104. One downlink data channel may be formed with one or more RBs.

  In the downlink frame structure of FIG. 1, a maximum of 50 downlink data channels can be simultaneously scheduled in one TTI 105. Therefore, a maximum of 50 uplink ACKCH is required. In practice, however, 10 or 20 data channels are scheduled on average with one TTI, and as many uplink ACKCHs as this data channel are required. Efficient resource allocation is important because the number of available ACKCHs is very different from the average number of actually used ACKCHs.

When the Node B is explicitly notified to the UE of the ACKCH set for each data channel for each TTI, only the required number of ACKCHs can be allocated in the TTI. Thus, in the case of downlink data transmission, the UE transmits ACK / NACK using the notified ACK / NACK resource. For uplink data transmission, the UE detects ACK / NACK transmitted by the Node B from ACK / NACK resources signaled by the Node B. Therefore, it is important to reduce the amount of resources for signaling, that is, signaling overhead. Explicit signaling of information about ACK / NACK resources from the Node B to the UE at each TTI results in significant signaling overhead.
Therefore, it is necessary to optimize the amount of resources allocated to ACKCH and signaling overhead of ACK / NACK resources in order to increase system capacity through efficient use of radio resources.

International Publication No. 2006/071049 Pamphlet International Publication No. 2004/114582 Pamphlet International Publication No. 2005/074184 Pamphlet

  Accordingly, an object of the present invention is to provide a resource allocation method and apparatus that optimizes the amount of ACK / NACK resources in a wireless communication system in order to solve the above-described problems of the prior art.

  It is another object of the present invention to provide a method and apparatus for optimizing signaling information overhead related to ACK / NACK resources in a wireless communication system.

  Another object of the present invention is to provide a method for signaling information on ACK / NACK resources in different manners based on whether data channel resources are scheduled persistently or non-persistently. And providing an apparatus.

  In order to achieve the above object, according to one aspect of the present invention, there is provided a method for allocating and signaling acknowledgment / negative acknowledgment (ACK / NACK) channel resources in a wireless communication system, which is predetermined. Within a fixed-size first resource group, ACK / NACK resources that are implicitly mapped to a scheduling control channel (SCCH) that sends scheduling information for non-persistent scheduling data channels are designated as ACK / NACKs for non-persistent scheduling data channels. ACK / NACK resource for transmission of ACK / NACK for a persistent scheduling data channel within a predetermined variable-sized second resource group, and determining to use for transmission of NACK And transmitting resource indication information that explicitly indicates the assigned ACK / NACK resource to at least one user terminal (UE).

  According to another aspect of the present invention, a base station apparatus that allocates and signals ACK / NACK resources in a wireless communication system, and includes non-persistent scheduling data in a first resource group having a predetermined fixed size. An ACK / NACK resource that is implicitly mapped to the SCCH that carries scheduling information about the channel is determined to be used for transmission of ACK / NACK for the non-persistent scheduling data channel, and a predetermined variable size number is determined. A controller that decides to allocate an ACK / NACK resource for transmission of ACK / NACK for a persistent scheduling data channel, and a resource that explicitly indicates the allocated ACK / NACK resource within two resource groups. Generating a scan instruction information, characterized in that it comprises a generator for transmitting to at least one UE.

  According to another aspect of the present invention, there is provided a method for receiving ACK / NACK resources in a wireless communication system, wherein a non-persistent scheduling data channel is assigned to a UE having a predetermined fixed size. Within one resource group, an ACK / NACK resource that is implicitly mapped to the SCCH sending scheduling information for the non-persistent scheduling data channel is used for transmission of ACK / NACK for the non-persistent scheduling data channel. And allocating for the ACKCH corresponding to the persistent scheduling data channel in the second variable-size second resource group when the persistent scheduling data channel is assigned to the UE. Characterized by having a receiving explicitly instructs resource indication information against which ACK / NACK resources.

  Furthermore, according to another aspect of the present invention, a UE apparatus that receives ACK / NACK resources in a wireless communication system, wherein a non-persistent scheduling data channel is assigned to a UE, and has a predetermined fixed size. Within the first resource group, ACK / NACK resources that are implicitly mapped to SCCH sending scheduling information for non-persistent scheduling data channels are used for transmission of ACK / NACK for non-persistent scheduling data channels. And allocating for the ACKCH corresponding to the persistent scheduling data channel within the second variable-sized second resource group when the persistent scheduling data channel is allocated to the UE Characterized in that it comprises a controller for determining to receive the resource indication information explicitly instruct the ACK / NACK resource, and a receiver for receiving a resource indication information under control of the controller.

  The present invention increases resource usage efficiency and reduces signaling overhead by applying appropriate ACK / NACK resource allocation and signaling scheme according to the non-persistent scheduling type or persistent scheduling type of data. Thus, the present invention has the effect of improving the system capacity by increasing the resources that can be used for transmission.

It is a figure which shows an example of a downlink resource structure. FIG. 6 is a diagram illustrating ACK / NACK resource allocation according to the present invention. FIG. 6 is a diagram illustrating a scheduling physical channel format according to the present invention. FIG. 6 is a diagram illustrating another ACK / NACK resource allocation scheme according to the present invention. It is a figure which shows an example of ACK / NACK resource allocation by this invention. 3 is a flowchart illustrating an operation of a Node B according to the present invention. 3 is a flowchart illustrating an operation of a UE according to the present invention. 6 is a flowchart illustrating an operation of a UE during HARQ transmission in the case of persistent scheduling according to the present invention. It is a block block diagram which shows the Node B apparatus by this invention. It is a block block diagram which shows UE apparatus by this invention. FIG. 6 is a diagram illustrating an ACK / NACK resource allocation scheme in a MIMO system according to another embodiment of the present invention. It is a figure which shows the allocation method of the ACK / NACK resource which considered the cell coverage by the 3rd Embodiment of this invention. It is a figure which shows the ACK / NACK resource allocation system by the 4th Embodiment of this invention.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In the following, it will be apparent to those skilled in the art that various modifications can be made in the embodiments of the present invention without departing from the scope and spirit of the present invention. In addition, when it is determined that a specific description regarding a known function or configuration related to the present invention makes the gist of the present invention unclear, a detailed description thereof will be omitted.

  In the embodiments of the present invention, the context of an EUTRA system based on an OFDM cellular radio communication system, particularly 3GPP UMTS (Universal Mobile Telecommunication Services), will be described. The main gist of the present invention is a similar technical background and channel structure. It will be apparent to those skilled in the art that minor modifications can be applied to other communication systems within the scope and spirit of the invention.

  The present invention relates to efficient allocation and signaling of channel resources in a wireless communication system. According to the present invention, different signaling schemes are used for ACK / NACK resource allocation based on the scheduling type of the data channel. Data channels can be scheduled in two ways according to the characteristics of the data traffic.

  First, in the case of irregular data transmission such as when browsing the Internet or using a game service, the Node B selects an appropriate radio resource and an appropriate TTI for data transmission each time data is generated. When transmitting data, the Node B signals scheduling information indicating a selection result to the UE on a scheduling control channel (hereinafter referred to as “SCCH”). This scheduling type is called non-persistent scheduling.

  In near real-time or regular data traffic such as VoIP (Voice over Internet Protocol), the Node B does not need to select a resource for data transmission for each TTI and notify the UE of the selected resource. Therefore, scheduling information related to resource allocation for data traffic is signaled once in the initial scheduling and is effective for subsequent data transmission. At this time, the validity of the scheduling information continues continuously or for a certain period of time. A scheduling type in which scheduling information is valid over multiple TTIs or multiple data packets is called persistent scheduling.

  In the present invention, ACK / NACK resources are allocated and signaled in different manners based on persistent and non-persistent scheduling types for data transmission. More specifically, in the case of non-persistent scheduling data transmission, the ACK / NACK resource is indicated by an index of SCCH. In the case of persistent scheduling data transmission, ACK / NACK resources are explicitly signaled during initial scheduling and remain valid thereafter. Since ACK / NACK resources are allocated based on this data scheduling type, the overall resource usage efficiency increases and the signaling overhead of ACK / NACK resources decreases.

  In a multi-input multi-output (MIMO) scheme in which a plurality of codewords can be simultaneously transmitted through a plurality of transmission and reception antennas via a single data channel, two or more ACKCHs are required for the codeword. Become. In this context, the present invention provides a method for allocating and signaling appropriate ACK / NACK resources for MIMO transmission.

  Here, the term “ACK / NACK resource” is defined as a resource allocated to ACKCH.

<First Embodiment>
FIG. 2 illustrates an ACK / NACK resource allocation scheme according to the present invention.

  Referring to FIG. 2, Node B scheduler 200 selects non-persistent scheduling 211 or persistent scheduling 212 for the data channel.

  In non-persistent scheduling 211, M SCCHs 203 carry scheduling information for M data channels. Each SCCH is a physical layer control channel that transmits scheduling information related to one data channel. The ACK / NACK resource in which ACK / NACK is transmitted for the data channel is implicitly indicated by the index of SCCH 203 mapped to the data channel. Therefore, different data channels, that is, different SCCHs 203, are mapped one-to-one to ACKCHs 207 in a fixed-size resource group 209, as indicated by reference numeral 205. .

  The simplest mapping rule is that SCCH # n is mapped to ACKCH # n, but other mapping rules are possible. The mapping between SCCH 203 and ACKCH 207 removes the need for Node B to explicitly signal the index of ACKCH 207 to the UE, thereby reducing signaling overhead.

  Meanwhile, in order to define SCCHs having various formats and sizes, CCEs (Control Channel Elements) each having a predetermined number of subcarriers are defined and labeled with CCE indexes. The SCCH can be formed with one or more CCEs. The index of one CCE (or more CCEs) forming the SCCH is mapped to ACK / NACK resources instead of the SCCH index. Therefore, the UE can know the assigned ACKCH index from the CCE index forming the SCCH without separately signaling the ACKCH index. Thus, ACK / NACK resources for non-persistent scheduling data are implicitly signaled by the CCE index instead of the SCCH 203 index. When one SCCH includes a plurality of CCEs, one of the CCE indexes, for example, the lowest CCE index can be mapped to an ACK / NACK resource.

  The case shown in FIG. 2 is based on the assumption that a maximum of M data channels can be scheduled in one TTI. The number of data channels scheduled for each TTI varies depending on the decision of the Node B scheduler 200, and the number of SCCH 203 and ACKCH 207 can also vary. In the case of non-persistent scheduling 211, the resource group 209 is preset for the maximum number of available data channels or more ACKCHs, thereby speeding up ACK / NACK resources without explicit signaling. Allocation becomes possible.

  In persistent scheduling 212, when a resource is scheduled for a data channel using SCCH 204 in the initial data transmission, the scheduling information for this resource may be stored continuously or a predetermined number without transmission of new scheduling information. This is valid for the subsequent TTIs.

  However, considering that the number of persistently scheduled UEs varies from cell to cell and the number of persistently scheduled data channels varies from TTI to TTI, the Node B is denoted by reference numeral 206. In the persistent scheduling 212, resource indication information indicating the ACKCH 208 in the flexible size resource group 210 is explicitly transmitted to the UE. This resource indication information is valid for the UE continuously while the same resource allocation is maintained for the data.

  If necessary, for example, to collect ACK / NACK resources scattered in the RB, ACK / NACK resources can be reassigned to the persistent scheduling data channel by additional signaling during the service. This ACK / NACK resource reallocation may be indicated by higher layer signaling information transmitted through a persistent scheduling data channel. The UE acquires ACK / NACK resource indication information from the higher layer signaling information, and transmits ACK / NACK to the data channel received thereafter with the resource indicated by the ACK / NACK resource indication information.

  As shown in FIG. 2, the ACK / NACK resource indication information related to the persistent scheduling data channel is the layer 1 (L1) / layer 2 (L2) or higher layer protocol on the control channel, as indicated by reference numeral 206. Signaled by information. Even when the persistent scheduling information related to the data channel is transmitted by L1 / L2 signaling, the ACK / NACK resource indication information can be transmitted by upper layer signaling. Since the transmission of initial scheduling information is sufficient for persistent scheduling 212, explicit signaling of ACK / NACK resource indication information greatly increases the signaling overhead even if as many ACK / NACK resources as necessary are allocated for each TTI. I won't let you.

  In persistent scheduling 212, data is transmitted on persistently scheduled resources during the initial HARQ transmission. If the initially transmitted data has errors, the Node B can explicitly schedule data channel resources for HARQ retransmission. Therefore, the ACK / NACK is transmitted for the retransmitted data through the ACKCH 207 of the fixed size resource group 209 that is implicitly mapped to the index of the SCCH 203 that schedules the data channel during HARQ retransmission. Alternatively, the ACK / NACK can be transmitted from the ACKCH that is continuously scheduled in the variable size resource group 210 through the same ACKCH or different ACKCH. Thus, the ACK / NACK resource used for initial HARQ transmission can be used for other channels.

  For example, if the ACK / NACK is transmitted through the ACKCH 207 mapped to the index of the SCCH that schedules data resources or the index of the CCE that forms the SCCH during HARQ retransmission, it is persistent for one UE. The ACK / NACK resources allocated for the scheduling data channel are limited to the initial HARQ transmission only. Since the Node B allocates the ACK / NACK resource allocated for the initial HARQ transmission to the ACKCH of another UE or another channel of this UE, the resource usage efficiency is improved. In other words, ACK / NACK resources that are persistently allocated by persistent data scheduling are only valid for initial HARQ transmissions, and ACK / NACK resources that are implicitly indicated by SCCH are transmitted during HARQ retransmissions. ACK / NACK transmission.

  The above ACK / NACK resource allocation is applied to both downlink and uplink. In the case of downlink data transmission, SCCHs 203 and 204 send resource indication information regarding downlink data from the Node B to the UE, and ACKCHs 207 and 208 transmit ACK / NACK for the downlink data from the UE to the Node B. In the case of uplink data transmission, SCCHs 203 and 204 carry resource indication information related to uplink data transmitted by the UE to Node B, and ACKCHs 207 and 208 send ACK / NACK for uplink data from Node B to the UE. .

  FIG. 3 shows an example of a downlink scheduling physical channel format according to the present invention when persistent scheduling information is transmitted by L1 / L2 signaling as non-persistent scheduling information. Reference numeral 300 denotes a non-persistent SCCH information format, and reference numeral 301 denotes a persistent scheduling control channel information format.

  Referring to FIG. 3, the UE receives and decodes the first part (Part 1) 303 of the SCCH and, based on the scheduling type indicator 302, whether this SCCH is non-persistent scheduling or persistent scheduling. Determine. The UE receives and decodes the second part (Part 2) 304 by the scheduling type indicator 302 to obtain the scheduling information 305 and 306. Scheduling information 305 or 306 includes resource indication information indicating resources allocated to the data channel, MCS (Modulation and Coding Scheme) level of the data channel, HARQ information, and MIMO information.

  The persistent scheduling information 306 further includes scheduling interval information and ACK / NACK resource indication information indicating a duration for which the persistent scheduling information 306 is valid, compared to the non-persistent scheduling information 305. The non-persistent SCCH format 300 is the same as the persistent SCCH format 301, and it may further be considered that the scheduling interval information and the ACK / NACK resource indication information are transmitted by L1 / L2 signaling or higher layer signaling, respectively.

  If the initial transmission is scheduled through persistent scheduling and signaled by L1 / L2 signaling, ACK / NACK resources can be implicitly indicated by SCCH as non-persistent scheduling. The ACK / NACK resource can be explicitly signaled with an initial data transmission that is persistently scheduled, or a next data transmission that is not indicated by the SCCH. For example, when persistent scheduling information is signaled to the UE through SCCH #k, the UE receives data on the data channel resource indicated by SCCH #k and is mapped to SCCH #k for this received data. ACK / NACK is transmitted through ACKCH # k. When the next data is received on the data channel resource, the UE responds to the data through the ACK / NACK resource explicitly indicated by the higher layer signaling information included in the data first received on the data channel resource. ACK / NACK is transmitted.

  The above usage example of ACKCH is applied to higher layer signaling of persistent scheduling information regarding a data channel. Since the data channel for transmitting initial data including persistent scheduling information as higher layer signaling information is scheduled for the UE by SCCH, the UE can receive ACK / NACK by ACK / NACK resources mapped to SCCE or CCE forming SCCH. NACK is transmitted. After successful reception of the initial data, the UE transmits ACK / NACK with ACK / NACK resources indicated by higher layer signaling information included in the initial data.

  FIG. 4 shows another ACK / NACK resource allocation scheme according to the present invention.

  Referring to FIG. 4, the ACKCH 403 for the persistent scheduling data channel shares a resource group 405 with a CQI channel (Channel Quality Indicator Channel: hereinafter referred to as “CQICH”) 404. The UE transmits state information regarding the downlink channel to the Node B through the CQICH 404. As indicated by reference numeral 401, Node B explicitly instructs each UE on transmission timing and resources to CQICH. Similar to ACKCH 403, the number of CQICHs 404 changes from cell to cell or from TTI to TTI. CQICH 404 and ACKCH 403 share variable size resource group 405, and Node B controls the resources allocated to ACKCH 403 and CQICH 404 in resource group 405 by shifting resource boundary 402 depending on the situation. Therefore, the entire resource can be used efficiently.

  FIG. 5 shows an example of ACK / NACK resource allocation according to the present invention. As an example, ACK / NACK resource allocation is performed in accordance with 3GPP EUTRA uplink SC-FDMA (Single Carrier-Frequency Division Multiple Access) standard.

  Referring to FIG. 5, a transmission bandwidth 500 of 10 MHz is divided into 50 resource units (hereinafter referred to as “RU”) 501-504, and each RU has 12 subcarriers. The ACKCH and CQICH apply different sequences to each other, or apply different cyclically shifted sequences of the same sequence to the first RU 501 (RU # 1) and the 49th RU503 (RU #). 49) and multiplexed by CDM (Code Division Multiplexing) of the 50th RU 504 (RU # 50). The data channel is multiplexed with ACKCH and CQICH by FDM (Frequency Division Multiplexing) of 2nd to 48th RUs 502 (RU # 2 to RU # 48).

  ACKCH # 1 through ACKCH # M, which are M ACKCHs for the non-persistent scheduling data channel, are transmitted by the CDM on RU # 1, and the remaining CDM resources of RU # 1 are ACKCH # ( M + 1) to ACKCH # 12. In addition to ACKCH # (M + 1) to ACKCH # 12, RU # 49 and RU # 50 are used as ACK / NACK resources for the persistent scheduling data channel. In a TTI with a small number of persistent scheduling data channels, RU # 49 and RU # 50 are used for data channels along with data channels 505 of RU # 2 to RU # 48, or are used exclusively for CQICH.

  In FIG. 5, RU # 49 is assigned to the first to Kth CQICHs 509 to 510 (CQICH # 1 to CQICH # K), but there is no need to draw a boundary within RU # 49, and CQICH is also assigned to RU # 50. Can be assigned. Since the amount and index of ACK / NACK resources and CQICH resources are controlled on a TTI basis, radio resources can be used as efficiently as necessary.

  In variable size resource group 405, instead of signaling absolute values such as cyclic shift value of CDM sequence, additional orthogonal sequence index, and transmitted RU index to UE, the offset from the boundary of fixed size ACKCH resource group is UE Can be signaled. As shown in FIG. 5, when each uplink channel index is defined by a combination of a cyclic shift value of a CDM sequence, an orthogonal sequence index, and a transmitted RU index, the offset is at the boundary of a fixed size ACKCH resource group. Called the relative index for ACKCH # M. For example, ACKCH # (M + m) is indicated by the offset m.

  FIG. 6 is a flowchart illustrating the operation of the Node B according to the present invention.

  Referring to FIG. 6, the Node B prepares to schedule uplink and / or downlink data channels and ACKCH for the UE in step 600. Specifically, the Node B collects information required for scheduling such as a scheduling type for data traffic, a buffer state, and a resource state. In step 601, Node B determines scheduling type and transmission format for a data channel such as allocated resources and MCS level, and then formats scheduling information according to the determination result.

  Node B determines at step 602 whether the scheduling type is persistent or non-persistent. As a result, in the case of persistent scheduling, the Node B determines ACK / NACK resources and formats ACK / NACK resource indication information to notify the UE of ACK / NACK resources in Step 603. This scheduling type is determined by the traffic characteristics of the data channel. In step 604, the Node B transmits data channel scheduling information and ACK / NACK resource indication information through L1 / L2 signaling or higher layer signaling.

  On the other hand, in the case of non-persistent scheduling, the ACK / NACK resource is determined by the index of the SCCH mapped to the data channel. Accordingly, the Node B transmits only the scheduling information of the data channel to the UE through the SCCH having the SCCH index in step 605.

  FIG. 7A is a flowchart illustrating an operation of the UE according to the present invention.

  Referring to FIG. 7A, in step 700, the UE obtains scheduling information by decoding the SCCH for each scheduling period (eg, each TTI). In step 701, the UE determines whether there is a data channel resource allocated to the UE in the current scheduling period, that is, determines whether the UE is scheduled in the current scheduling period from the scheduling information. If the UE is not scheduled, the UE returns to step 700. If the UE is scheduled, in step 702, the UE transmits the scheduled data according to the scheduling information (when uplink data transmission is scheduled) or decodes (when downlink data reception is scheduled). )

  In step 703, the UE determines whether the scheduling type of the data used in step 702 is persistent or non-persistent. The UE can determine the scheduling type from the scheduling type indicator of the scheduling information or the traffic characteristics of the data channel. For the persistent scheduling type, the UE detects ACK / NACK resources that explicitly indicate when data was initially scheduled by persistent scheduling in step 704. Thereafter, in step 706, the UE transmits ACK / NACK to the Node B using the ACKCH resource when downlink data reception is scheduled, or ACK / NACK is transmitted from the Node B using the ACKCH resource when uplink data transmission is scheduled. / NACK is received.

  For the non-persistent scheduling type, the UE detects an ACK / NACK resource that is implicitly mapped to the SCCH corresponding to the non-persistent scheduling data channel in step 705, and in step 706, the ACK / NACK resource. ACK / NACK is transmitted / received with Node B.

  FIG. 7B is a flowchart illustrating an operation of the UE when transmitting ACK / NACK in the uplink for the persistent scheduling downlink data channel according to the present invention.

  Referring to FIG. 7B, in step 711, the UE receives persistent scheduling information in which resources for the downlink data channel and the uplink ACKCH are continuously scheduled by L1 / L2 signaling or higher layer signaling. That is, the persistent scheduling information includes ACK / NACK resource indication information for the uplink ACKCH. In step 712, the UE periodically receives data packets over the persistent scheduling data channel with persistent scheduling information.

  In step 713, the UE determines whether the data packet is an initial HARQ transmission packet or a HARQ retransmission packet. The UE proceeds to step 715 if it is an initial HARQ transmission, and proceeds to step 714 if it is a HARQ retransmission. In step 715, the UE transmits an ACK / NACK for the data packet with the ACK / NACK resource explicitly indicated in step 701. In step 714, the UE determines whether persistent scheduling information has been received with the data packet. If these are received separately, the UE transmits an ACK / NACK for the data packet in step 715 with the ACK / NACK resource explicitly indicated in step 701. On the other hand, if persistent scheduling information is received along with the data packet, the UE transmits an ACK / NACK in step 716 through the ACKCH mapped to the SCCH or the CCE of this SCCH.

FIG. 8 is a block diagram illustrating a Node B apparatus according to the present invention.
Referring to FIG. 8, the data channel scheduler 800 determines radio resources and MCS levels for data according to data channel scheduling. The scheduling information generator 803 generates scheduling information indicating the determination result of the data channel scheduler 800, and the control channel generator 805 channel-codes the scheduling information and transmits it through the SCCH. This scheduling information can be transmitted by L1 / L2 signaling or higher layer signaling.

  Controller 801 decides to use ACK / NACK channel resources that are implicitly mapped to SCCH for non-persistent scheduling data channels. For the persistent scheduling data channel, the controller 801 determines that an ACK / NACK resource needs to be allocated in the variable size resource group, and notifies the ACKCH scheduler 802 of the result.

  The ACKCH scheduler 802 determines resource allocation for the ACKCH for the data channel. Under the control of the controller 801, the ACKCH for the non-persistent scheduling data channel is not scheduled, and only the resource for the ACKCH is allocated in the variable size resource group for the persistent scheduling data channel. The instruction information generator 804 generates ACK / NACK resource instruction information that explicitly instructs the determination of the ACKCH scheduler 802. The control channel generator 805 channel-codes the ACK / NACK resource indication information, and then transmits the information by L1 / L2 scheduling or higher layer scheduling.

  FIG. 9 is a block diagram illustrating a UE receiver according to the present invention.

  Referring to FIG. 9, the SCCH decoder 900 detects an SCCH signal mapped to an SCCH resource from a received (RX) signal 906, and acquires scheduling information by decoding the SCCH signal. If the scheduling information is successfully decoded, the controller 901 determines whether the scheduling information indicates a persistent scheduling type or a non-persistent scheduling type. In the case of the persistent scheduling type, the controller 901 controls the multiplexer (MUX) 902 according to the signaling scheme of the ACK / NACK resource, and sends a signaling signal indicating the ACK / NACK resource among the received signals to the indication information decoder 903. provide. When the ACK / NACK resource signaling signal is included in the scheduling information, the MUX 902 selects the scheduling information and provides it to the instruction information decoder 903.

  The instruction information decoder 903 obtains ACK / NACK resource instruction information by decoding the signaling signal included in the scheduling information. During downlink data reception, the ACK / NACK resource indication information is used by the ACK / NACK generator and mapper 904 to generate ACK / NACK for the downlink data and map it to the ACK / NACK resource. For uplink data transmission, the ACK / NACK resource indication information is used by the ACK / NACK detector 905 to detect ACK / NACK mapped from the RX signal 906 to the ACK / NACK resource.

  For non-persistent scheduling, the controller 901 detects ACK / NACK resources that are implicitly mapped to SCCH indication resources for non-persistent data channels and uses ACK / NACK for use in ACK / NACK transmission or reception. The NACK resource is notified to the ACK / NACK generator / mapper 904.

<Second Embodiment>
FIG. 10 shows an ACK / NACK resource allocation scheme for a MIMO system according to another embodiment of the present invention.

  The MIMO scheme is divided into SCW (Single Code Word) -MIMO and MCW (Multi-Code Word) -MIMO. In MCW-MIMO in which a transmitter transmits a plurality of codewords simultaneously, decoding is performed for each codeword. Therefore, as many ACKCHs as the number of transmitted codewords are required. Accordingly, as shown in FIG. 10, the ACKCH for at least one codeword (eg, the first codeword) on the non-persistently scheduled MCW-MIMO data channel is While using ACK / NACK resources mapped to the SCCH index for one codeword, the ACK / NACK resources for the remaining codewords are non-persistent scheduling MCW-MIMO data channels, as represented by reference numeral 1003 Is explicitly signaled with SCCH 1002 for. This ACK / NACK resource shares the variable size resource group 1005 with the ACKCH for the persistent scheduling data channel.

  That is, for non-persistent scheduling of MCW-MIMO data, Node B allocates ACK / NACK resources as indicated by reference numeral 1003 in consideration of the allocation state of ACK / NACK resources 1005 in TTI units. A part of the variable-size ACK / NACK resource 1005 is allocated to a codeword that cannot be used. Sharing the resource group 1005 between the ACKCH for non-persistent scheduling MCW-MIMO data channel and the ACKCH for persistent scheduling MCW-MIMO data channel enables efficient use of radio resources.

  For non-MIMO and SCW-MIMO data channels, the ACK / NACK resource that is implicitly signaled by the index of SCCH 1001 is used as indicated by reference numeral 1006 as described above. Therefore, ACK / NACK for non-MIMO and SCW-MIMO data channels is transmitted through ACKCH in fixed size resource group 1004.

<Third Embodiment>
FIG. 11 shows an ACK / NACK resource allocation scheme according to the third embodiment of the present invention. The ACK / NACK resource is allocated in consideration of cell coverage of ACKCH. Here, the 3GPP EUTRA standard takes into account that 1 ms TTI is defined.

  The cell coverage of ACKCH is defined as the cell radius where ACKCH is stably detected. In order to extend the cell coverage for the limited maximum transmission power, it is necessary to increase the reception energy of the ACKCH at the receiver by extending the transmission period of the ACKCH. However, as the ACKCH transmission period is extended, the amount of resources occupied by the ACKCH increases proportionally.

  Therefore, for efficient use of radio resources, the variable-size resource group 1101 for the persistent scheduling data channel includes a first resource group 1107 having a 1 ms transmission interval and a second resource group having a 0.5 ms transmission interval. Divided into resource groups 1108. ACKCH # 2.x with 0.5 ms transmission interval 1105 or ACKCH # 1.x with 1 ms transmission interval 1104 is assigned to the UE according to persistent scheduling. The transmission time of the allocated ACKCH is indicated by the ACK / NACK resource indication information, or preset between the system and the UE by the position of the ACK / NACK resource or the index of the ACKCH.

  For UEs close to Node B with sufficient transmit power, Node B transmits ACK / NACK in 0.5 ms with high power by assigning ACKCH # 2.x in second resource group 1108 To the UE, thereby reducing ACK / NACK resource overhead. For UEs at cell boundaries that do not have sufficient transmit power, Node B increases the ACKCH received energy by assigning ACKCH # 1.x in the first resource group 1107 to the UE, This increases the ACK / NACK detection probability. This Node B determines whether the UE is near or at the cell boundary according to the channel condition reported by the UE, the signal strength of the signal received from the UE, or the geographical location of the UE.

  The boundary 1106 between the first and second resource groups 1107 and 1108 can vary for each cell and TTI. The ACKCH of the second resource group 1108 is not necessarily transmitted continuously in 0.5 ms. For example, ACKCH # 2.1 and ACKCH # 2.2 are alternately transmitted in two discontinuous 0.25 ms intervals, and frequency hopping may occur in the next 0.5 ms interval. For example, ACKCH # 1 is transmitted with a discontinuous time period between 0 and 0.25 ms and between 0.5 ms and 0.75 ms, and ACKCH # 2 is transmitted with 0.25 ms and 0 It is transmitted with a discontinuous period between .5 ms and between 0.75 ms and 1 ms. ACKCH # 1 and ACKCH # 2 are transmitted on the first frequency resource (for example, RU # 1) for the first 0.5ms period, and the second frequency resource for the next 0.5ms period. Frequency hopped to (for example, RU # 50). At this time, the entire transmission interval of ACKCH # 2.x is 0.5 ms, but since transmission is discontinuous and frequency hopping, frequency and time diversity can be obtained. This variable size ACK / NACK resource 1101 is shared not only with ACKCH for persistent scheduling data, but also between CQICH and ACKCH for MCW-MIMO data channel.

  On the other hand, since the ACKCH for the non-persistent scheduling data channel is dynamically allocated by the index of the SCCH for each TTI, the ACKCH of the fixed size resource group 1100 is commonly used for 1 ms transmission time 1103 in order to prevent cell coverage problems. Have The ACKCH of the fixed size resource group 1100 can be multiplexed in the code or frequency domain 1102.

<Fourth Embodiment>
FIG. 12 shows an ACK / NACK resource allocation scheme according to the fourth embodiment of the present invention.

  Referring to FIG. 12, the ACK / NACK for the non-persistent scheduling data channel uses the ACK / NACK resource of the fixed size resource group 1202 mapped to the SCCH for the data channel as in the first embodiment of the present invention. To do. The ACK / NACK resource can be mapped to at least one CCE forming the SCCH instead of the SCCH. At this time, the ACKCH for the data channel indicated by the SCCH uses a resource corresponding to at least one CCE forming the SCCH, and the UE implicitly recognizes the ACK / NACK resource by the CCE index.

  Compared to the first embodiment of the present invention, in the fourth embodiment, not only the variable size resource group 1205 but also the resources of the fixed size resource group 1202 have ACKCH, CQICH, and other channels for the persistent scheduling data channel. It can be used for at least one of them.

  For example, when a small number of SCCHs are used for a small number of active UEs in a cell or a small number of UEs scheduled for one TTI, many resources are used in the fixed size resource group 1202 Remain except for ACK / NACK resources mapped to the assigned SCCH. In this case, the Node B allocates the remaining resources and the variable size resource group 1205 to the UE according to the explicit indication 1204, so that the remaining resources are ACKCH, CQICH, and other channels for the persistent scheduling data channel. Used for at least one transmission. The UE uses the ACKCH, CQICH for persistent scheduling data channel, and the remaining resources for other channels.

  As mentioned above, in the detailed description of the present invention, specific embodiments have been described. However, it is understood by those skilled in the art that various modifications can be made without departing from the scope of the claims. Is clear. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined based on the description of the scope of claims and equivalents thereof.

800 ... Data channel scheduler 801 ... Controller 802 ... ACKCH scheduler 803 ... Scheduling information generator 804 ... Instruction information generator 805 ... Control channel generator 900 ... SCCH decoder 901 ... Controller 902 ... MUX
903 ... Instruction information decoder 904 ... ACK / NACK generator and mapper 905 ... ACK / NACK detector

Claims (16)

A method for receiving a physical downlink control channel in a wireless communication system, comprising:
Receiving a physical downlink control channel;
Decoding the received physical downlink control channel;
A step of determining a scheduling type by using the scheduling information indicating scheduling type that is included in the physical downlink control channel the received,
A step of acquiring the scheduling information for the data channel by the determined scheduling type,
I have a,
The method according to claim 1, wherein the scheduling type is non-persistent scheduling or persistent scheduling . The method of claim 1 , wherein the scheduling information includes resource information indicating resources for the data channel, a modulation and coding scheme (MCS) of the data channel, and HARQ information. Receiving the data channel using the acquired scheduling information;
And transmitting the ACK / NACK with respect to the data channels by the determined scheduling type,
The method according to claim 1 or 2, characterized in that it further comprises a. The step of transmitting the ACK / NACK includes:
If the scheduling type is non-persistent scheduling, send the ACK / NACK based on a control channel element (CCE) index;
The method of claim 3 , wherein when the scheduling type is persistent scheduling, the ACK / NACK is transmitted based on information configured by an upper layer. An apparatus for receiving a physical downlink control channel in a wireless communication system, comprising:
A receiver for receiving a physical downlink control channel;
The received physical downlink control channel is decoded, a scheduling type is determined using scheduling information indicating a scheduling type included in the received physical downlink control channel, and a data channel is determined according to the determined scheduling type. A decoder for obtaining scheduling information for:
Only including,
The apparatus characterized in that the scheduling type is non-persistent scheduling or persistent scheduling . The apparatus of claim 5 , wherein the scheduling information includes resource information indicating resources for the data channel, modulation and coding scheme (MCS) of the data channel, and HARQ information. The receiver receives the data channel using the acquired scheduling information;
Apparatus according to claim 5 or 6, characterized in that it comprises a transmitter further transmits an ACK / NACK to the data channels by the determined scheduling type. The transmitter is
If the scheduling type is non-persistent scheduling, send the ACK / NACK based on a control channel element (CCE) index;
The apparatus of claim 7 , wherein when the scheduling type is persistent scheduling, the ACK / NACK is transmitted based on information configured by an upper layer. A method for transmitting a physical downlink control channel in a wireless communication system, comprising:
Transmitting a physical downlink control channel;
The physical downlink control channel includes scheduling information indicating a scheduling type and scheduling information for a data channel,
Scheduling information indicating the scheduling type is used to decode the physical downlink control channel ;
The method according to claim 1, wherein the scheduling type is non-persistent scheduling or persistent scheduling . The method of claim 9 , wherein the scheduling information includes resource information indicating resources for the data channel, modulation and coding scheme (MCS) of the data channel, and HARQ information. Transmitting the data channel using the scheduling information;
The method according to claim 9 or 10 , further comprising receiving an ACK / NACK from the data channel according to the scheduling type. Receiving the ACK / NACK comprises:
Receiving the ACK / NACK based on a control channel element (CCE) index if the scheduling type is non-persistent scheduling;
The method of claim 11 , wherein if the scheduling type is persistent scheduling, the ACK / NACK is received based on information configured by an upper layer. An apparatus for transmitting a physical downlink control channel in a wireless communication system,
Including a transmitter for transmitting a physical downlink control channel;
The physical downlink control channel includes scheduling information indicating a scheduling type and scheduling information regarding a data channel,
Scheduling information indicating the scheduling type is used to decode the physical downlink control channel ;
The apparatus characterized in that the scheduling type is non-persistent scheduling or persistent scheduling . The apparatus of claim 13 , wherein the scheduling information includes resource information indicating resources for the data channel, modulation and coding scheme (MCS) of the data channel, and HARQ information. The transmitter transmits the data channel using the scheduling information;
The apparatus of claim 13 or 14 , further comprising a receiver that receives ACK / NACK from the data channel according to the scheduling type. The receiver is
Receiving the ACK / NACK based on a control channel element (CCE) index if the scheduling type is non-persistent scheduling;
The apparatus of claim 15 , wherein when the scheduling type is persistent scheduling, the ACK / NACK is received based on information configured by an upper layer.

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