KR20090046652A - Method for transmitting ack/nack information in egprs system - Google Patents

Abstract

A method of transmitting ACK (Acknowledgement) / NACK (Negative Acknowledgement) information in a wireless communication system. The method includes receiving a message including an internal ACK / NACK field indicating whether ACK / NACK information is included in a data block and a data block including ACK / NACK information of the received data block according to the indication of the message. Transmitting a step. The network and / or the mobile station may transmit ACK / NACK information for the received data block without a separate message.

Description

Method for transmitting ACK / NACK information in EGPRS system {Method for transmitting ACK / NACK information in EGPRS system}

The present invention relates to wireless communication, and more particularly, to a method of transmitting ACK / NACK information related to a reception state of a data block in a wireless communication system.

Global System for Mobile communication (GSM) is one of the wireless technologies that has been developed based on many subscribers since it was created as one of the means to unify the wireless means of communication in Europe. General Packet Radio Service (GPRS) is introduced to provide a packet-switched data service in a circuit-switched data service provided by GSM.

EDGE (Enhanced Data Rate for GSM Evolution) is a method of using 8-PSK (Phase Shift Keying) as a modulation method instead of Gaussian Minimum Shift Keying (GMSK), which is a modulation scheme used in GSM. Implementing GPRS through EDGE is called Enhanced GPRS (EGPRS). Since EGPRS is based on the same structure as GPRS, it is an evolution of GPRS. EGPRS optimizes the transmission rate by changing the modulation method and the coding method according to the wireless environment. The EGPRS2 system, which is a system having an additional modulation scheme and coding scheme, has also been developed. Hereinafter, EGPRS and EGPRS2 are collectively referred to as EGPRS.

The GSM / GPRS system is a system based on time division multiple access (TDMA). Information items transmitted in a communication relationship between a base station subsystem (BSS) and a mobile station (MS) arrive at a base station or mobile station in accordance with a timeslot. In the following, downlink means communication from a base station to a mobile station, and uplink means communication from a mobile station to a base station.

EGPRS performs a process called link adaptation for high-speed packet data transmission. For example, packet data is transmitted using nine different Modulation and coding schemes (MCS). MCS is adjusted according to channel conditions. If the channel condition is good (e.g., the SNR (Signal-To-Noise Ratio) is high), the MCS with the high data rate is selected. Conversely, if the channel condition is bad (or the SNR is low), the MCS with the lower data rate is selected.

Link adaptation is performed by a Radio Link Control (RLC) / Medium Access Control (MAC) layer. The RLC / MAC layer is located at the mobile station and the base station. Protocol Data Units (PDUs) of the LLC layer coming into the RLC entity are divided into RLC / MAC block units by the RLC entity and then communicated in RLC / MAC block units. Each RLC / MAC block is numbered by a block sequence number (BSN). The BSN tracks the RLC / MAC block between the receiving RLC / MAC entity and the sending RLC / MAC entity and uses it to correct the error block. In downlink transmission, the base station requests the state of the receiving block from the mobile station, which responds with a PACKET DOWNLINK ACK / NACK message. In uplink transmission, the mobile station requests the base station for the state of the receive block, and the base station responds with a PACKET UPLINKK ACK / NACK message.

Processes used in the MAC / RLC layer include the 3rd Generation Partnership Project (3GPP); Technical Specification Group GSM / EDGE Radio Access Network; General Packet Radio Service (GPRS); Mobile Station (MS)-Base Station System (BSS) interface; Radio Link Control / Medium Access Control (RLC / MAC) protocol (Release 7), 3GPP TS 44.060 V7.8.0 (2007-03).

Sections 10.3a.3 and 10.3a.4 of the 3GPP specification indicate uplink RLC / MAC headers and downlink RLC / MAC headers for various MCSs. The uplink state flag (USF) of the fields (filed) included in the header indicates the owner or use of the next uplink radio block on the same timeslot. The Relative Reserved Block Period (RRBP) field specifies a single uplink block through which the mobile station will send a PACKET CONTROL ACKNOWLEDGEMENT message or a Packet Associated Control Channel (PACCH) block to the network. The ES / P (EGPRS Supplementary / Polling) field indicates whether the RRBP field is valid or invalid.

As described above, for a received RLC / MAC block, the mobile station (or network) reports the reception status through a separate Acknowledgment (ACK) / Negative-Acknowledgement (NACK) message. There is no disclosure of a method for reporting a reception status in a resource block for packet data transmission.

An object of the present invention is to provide a method for transmitting ACK / NACK information in the EGPRS system.

In one aspect, a method for transmitting ACK (Acknowledgement) / NACK (Negative Acknowledgement) information in a wireless communication system. The method includes receiving a message including an internal ACK / NACK field indicating whether ACK / NACK information is included in a data block and a data block including ACK / NACK information of the received data block according to the indication of the message. Transmitting a step.

In another aspect, a mobile station is provided in an EGPRS system. The mobile station includes an RF unit for transmitting and receiving radio signals and a processor coupled to the RF unit and having an RLC / MAC layer. The processor receives whether ACK / NACK information is included when establishing or resetting TBF, and includes ACK / NACK information which is a reception state of a received downlink RLC / MAC block when the inclusion of ACK / NACK information is indicated. An uplink RLC / MAC block is generated and the uplink data block is transmitted.

The network and / or the mobile station may transmit ACK / NACK information for the received data block without a separate message.

1 is a block diagram illustrating a wireless communication system. This represents a Global System for Mobile communication (GSM) / General Packet Radio Service (GPRS) / Enhanced GPRS (EGPRS) based network. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

Referring to FIG. 1, a mobile station (MS) 10 refers to communication equipment carried by a user and includes a user equipment (UE), a user terminal (UT), a subscriber station (SS), and a wireless device. Etc. may be called.

A base station subsystem (BSS) 20 includes a base transceiver station (BTS) 22 and a base station controller (BSC) 24. The BTS 22 communicates with the mobile station 10 in one cell area through an air interface, and performs functions such as synchronization with the mobile station 10. The BSC 24 interfaces at least one BTS 22 with the Mobile Switching Center (MSC) 30.

The MSC 30 connects a heterogeneous network such as a Public Switching Telephone Network (PSTN) 65 or a Public Land Mobile Network (PLMN) to the base station 20 through a Gateway MSC (GMSC) 60. The VLR (Visitor Location Register) 40 stores temporary user data and contains information about roaming of all mobile stations 10 in the MSC 30 service area. The Home Location Register (HLR) 50 contains information about all subscribers in the home network. The Serving GPRS Support Node (SGSN) 70 is responsible for mobility management of subscribers. The Gateway GPRS Support Node (GGSN) routes the packet to the current location of the mobile station 10 and interfaces with an external packet data network, such as a Public Data Network (PDN).

In the following description, a radio resource (RR) mode shows a state of a radio resource in which a mobile station stays in an upper layer indicating whether a circuit switched scheme, a packet switched scheme, or a circuit switched scheme and a packet switched scheme are simultaneously supported. Idle mode means that no RR connection exists. Dedicated mode means that a Radio Resource (RR) connection is established. An RR connection is a physical connection used by two peer entities to support the exchange of higher layers of the information flow. Packet idle mode refers to the provision of a temporary block flow (TBF), and packet transfer mode refers to the provision of radio resources to a mobile station so that at least one TBF is provided. TBF refers to a physical connection used between two radio resource entities supporting unidirectional transmission of a Logical Link Control (LLC) Protocol Data Unit (PDU) on a packet data physical channel. At least one TBF is provided in a packet transfer mode. TBF is identified by the Temporary Flow Identity (TFI). The TFI is assigned to each TBF by the network and is unique among the TBFs that are concurrent in each direction.

2 is a block diagram illustrating elements of a mobile station. The mobile station 50 includes a processor 51, a memory 52, an RF unit 53, a display unit 54, and a user interface unit 55. . Memory 52 is coupled to processor 51 to store mobile station drive systems, applications, and general files. The display unit 54 displays various information of the mobile station, and may use well-known elements, such as a liquid crystal display (LCD) and organic light emitting diodes (OLED). The user interface unit 55 may be a combination of a well-known user interface such as a keypad or a touch screen. The RF unit 53 is connected to a processor and transmits and / or receives a radio signal.

The processor 51 implements the functions of the Radio Link Control (RLC) layer and the Medium Access Control (MAC) layer. The processor generates a data block (eg, an RLC / MAC block) transmitted through a radio block. The data block includes at least one RLC data block and ACK / NACK information. The processor 51 establishes or reconfigures the TBF.

3 is a conceptual diagram illustrating a radio block. A radio block is a unit used to transmit one data block. The radio block is transmitted through a packet data channel (PDCH).

Referring to FIG. 3, one frame consists of eight timeslots TS0, TS1,..., TS7 in the EGPRS system. A radio block consists of four consecutive timeslots belonging to different frames. For example, the radio block may be configured by taking the first timeslot TS0 one by one in four consecutive frames. Here, the first timeslot TS0 is taken, but other timeslots may be taken.

According to the structure of FIG. 3, one radio block is transmitted for 4 transmission time intervals (TTIs). One TTI is the time taken to transmit one frame.

A radio block can be transmitted on two PDCHs, and the two PDCHs are also referred to as one PDCH-pair. When the structure of FIG. 3 is referred to as a basic transmission time interval (BTTI) structure, this is called a reduced transmission time interval (RTTI). In the RTTI structure, a radio block is transmitted in two consecutive frames in one frame, and thus one radio block is transmitted for 2 TTIs.

4 is a flowchart illustrating a method of transmitting ACK / NACK information according to an embodiment of the present invention.

Referring to FIG. 4, TBF is established or reconfigured between the network and the mobile station (S210). Establishing a TBF means setting up a new TBF, and resetting TBF means changing a setting of an existing TBF. The messages used to set up or reestablish TBF include PACKET DOWNLINK ASSIGNMENT message, PACKET TIMESLOT RECONFIGURE message, MULTIPLE TBF DOWNLINK ASSIGNMENT message, and MULTIPLE TBF TIMESLOT RECONFIGURE message.

Upon establishing or resetting the TBF, the network informs whether the ACK / NACK information is used for a given TBF. That is, the network includes an inner ACK / NACK field in the message sent to the mobile station upon the establishment or resetting of the TBF. The inner ACK / NACK field indicates whether to include ACK / NACK information in the data block. The data block refers to a block transmitted through a radio block. Hereinafter, the data block will be described as an RLC / MAC block exchanged between RLC / MAC entities.

The network transmits a downlink RLC / MAC block (S220).

When the internal ACK / NACK field is set for the allocated TBF, the mobile station informs the base station of the reception state of the downlink data block (RLC / MAC block) through the ACK / NACK information included in the uplink data block ( S230).

The ACK / NACK information refers to a reception state of a downlink RLC / MAC block. The ACK / NACK information may include whether decoding of at least one RLC data block included in the downlink RLC / MAC block is successful or decoding of the RLC / MAC header is successful. The ACK / NACK information may consist of one bit, two bits, or more bits, and the number of bits is not limited.

Through the internal ACK / NACK field, the reception state of the data block for the TBF allocated in one direction is included in the data block transmitted in the other direction and transmitted. In the BTTI structure, 4 TTIs are required to transmit one radio block, and more TTIs may be required to transmit a reception state in a separate message. By checking the reception state of the downlink data block through the ACK / NACK information included in the uplink data block, a message for transmitting separate ACK / NACK information is not required. In addition, by indicating whether or not the ACK / NACK information is included in the data block when the TBF is set, it is not necessary to signal whether or not to transmit and / or receive additional ACK / NACK information for the corresponding TBF.

5 shows an example of a data block. The RLC / MAC block includes an RLC / MAC header, at least one RLC data block and ACK / NACK information. The RLC data block contains at least one upper layer PDU. The RLC / MAC header indicates whether information about the RLC data block and the ACK / NACK information is included.

6 shows another example of a data block. The RLC / MAC block of FIG. 6 includes up to four RLC data blocks and includes ACK / NACK information.

7 shows an example of an RLC / MAC header.

Referring to FIG. 7, the RLC / MAC header includes a TFI field, an AN field, an uplink state flag (USF) field, and the like. The TFI field identifies the TBF to which the RLC data block belongs. The USF indicates the owner or use of the next uplink radio block on the same timeslot. The PR (Power Reduction) field indicates a power level reduction of the current RLC / MAC block. In this example, the BSN (Block Sequence Number) field is assumed to have two RLC data blocks in the RLC / MAC block, and there are BSN1 and BSN2. BSN2 is a value relative to BSN1. The Combined EGPRS Supplementary / Polling (CES / P) field indicates which field the next uplink radio block reserved by this field contains. The Coding and Puncturing Scheme indicator (CPS) field indicates the type of channel coding and puncturing used for the data blocks.

The AN field indicates the presence or absence of ACK / NACK information in the RLC / MAC block. That is, the network first finds the AN field in the RLC / MAC header of the received uplink RLC / MAC block. If the AN field indicates that there is ACK / NACK information, the reception state of a previously transmitted downlink RLC / MAC block can be known through the ACK / NACK information.

Here, although the transmission of the uplink block is described, the technical idea of the present invention can be applied to the transmission of the downlink block. TBF configuration in uplink transmission may be made through a PACKET UPLINK ASSIGNMENT message or a MULTIPLE TBF UPLINK ASSIGNMENT message. The message may include an internal ACK / NACK field to inform whether the RLC / MAC block includes ACK / NACK information. After transmitting an uplink RLC / MAC block, the mobile station receives a downlink RLC / MAC block including ACK / NACK information for the uplink RLC / MAC block from the network.

The invention can be implemented in hardware, software or a combination thereof. In hardware implementation, an application specific integrated circuit (ASIC), a digital signal processing (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, and a microprocessor are designed to perform the above functions. , Other electronic units, or a combination thereof. In the software implementation, the module may be implemented as a module that performs the above-described function. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

As mentioned above, preferred embodiments of the present invention have been described in detail, but those skilled in the art to which the present invention pertains should understand the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated that various modifications or changes can be made. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

1 is a block diagram illustrating a wireless communication system.

2 is a block diagram illustrating elements of a mobile station.

3 is a conceptual diagram illustrating a radio block.

4 is a flowchart illustrating a method of transmitting ACK / NACK information according to an embodiment of the present invention.

5 shows an example of a data block.

6 shows another example of a data block.

7 shows an example of an RLC / MAC header.

Claims (6)

In the method for transmitting ACK (Acknowledgement) / NACK (Negative Acknowledgement) information in a wireless communication system, Receiving a message including an internal ACK / NACK field indicating whether ACK / NACK information is included in a data block; And Transmitting a data block including ACK / NACK information of the received data block according to the indication of the message. The method of claim 1, The message is a message for establishing or resetting a temporary block flow (TBF). The method of claim 1, The data block is a Radio Link Control (RLC) / Medium Access Control (MAC) block. The method of claim 3, wherein The RLC / MAC block includes an RLC / MAC header, at least one RLC data block, and the ACK / NACK information, and the RLC / MAC header includes a field indicating whether the ACK / NACK information is included. How to. RF unit for transmitting and receiving a radio signal; And A processor coupled to the RF unit and having a RLC / MAC layer; The processor receives whether ACK / NACK information is included when establishing or resetting TBF, and includes ACK / NACK information which is a reception state of a received downlink RLC / MAC block when the inclusion of ACK / NACK information is indicated. A mobile station in an EGPRS system, characterized by generating an uplink RLC / MAC block and transmitting the uplink data block. The method of claim 5, wherein The uplink RLC / MAC block further includes an RLC / MAC header, wherein the RLC / MAC header includes a field indicating the presence or absence of the ACK / NACK information.

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