KR20090050134A - Apparatus and method for data transmission communication system - Google Patents

Abstract

The present invention is to improve the data transmission rate of the 4th generation wireless mobile communication system that transmits a large amount of data such as mWiMAX, LTE, WLAN, DMB, etc., and transmits the data to MCS (Modulation and Coding Scheme) level or data transmission type. A serial / parallel conversion unit for converting and storing the I / Q data, and allocating the I / Q data to a frame to be transmitted, and before performing the inverse fast Fourier transform process. A subchannel allocator for mapping I / Q data to a location of a memory for temporarily storing the header, a header generator for generating a mapping header indicating a format of data to be allocated to the frame, the mapping header and the I / Q data Including a symbol memory for temporarily storing the I / Q data, the transmitter transmits the data using header information and I / Q data of data necessary for the mapping process. As it can be solved according to the waste problem of the problem of symbol memory of the transmitting device of the conventional mobile communication system.

Transmitter, OFDM, Orthogonal Frequency Division Multiplexing

Description

Apparatus and method for data transmission in mobile communication system {APPARATUS AND METHOD FOR DATA TRANSMISSION COMMUNICATION SYSTEM}

The present invention relates to a communication system using orthogonal frequency division multiplexing, and more particularly, to increase the data rate of a fourth generation wireless mobile communication system that transmits a large amount of data such as mWiMAX, LTE, WLAN, or DMB. An apparatus and method for significantly reducing modem size and modem power consumption by reducing memory.

Orthogonal Frequency Division Multiplexing (OFDM), which has recently been used as a useful method for high-speed data transmission in wired and wireless channels, is a method of transmitting data using a multi-carrier. Multi Carrier Modulation (MCM), which converts a symbol string in parallel and modulates each of them into a plurality of subcarriers having a mutual orthogonality, that is, a plurality of sub-channels. It's a kind of way.

Such a system using a multi-carrier modulation scheme was first applied to military high frequency radios (HF radio) in the late 1950s, and the OFDM scheme, which overlaps a plurality of orthogonal subcarriers, has been developed since the 1970s. Due to the difficulty in implementing the modulation, practical system applications have been limited.

However, in 1971, Weinstein et al. Announced that modulation and demodulation using the OFDM scheme can be efficiently processed using a Discrete Fourier Transform (DFT). In addition, the use of guard intervals and the insertion of cyclic prefix guard intervals have been known to solve the problems of the system for multipath and delay spread.

Accordingly, the OFDM technology provides digital transmission such as digital audio broadcasting (DAB), digital television, wireless local area network (WLAN), and wireless asynchronous transfer mode (WATM). It is widely applied to the technology. That is, the OFDM scheme is not widely used due to hardware complexity, but recently, various digital signal processing technologies including a Fast Fourier Transform (FFT) and an Inverse Fast Fourier Transform (IFFT) are used. This development made it possible.

Although the OFDM scheme is similar to the conventional Frequency Division Multiplexing (FDM) scheme, the OFDM scheme maintains orthogonality among a plurality of subcarriers and transmits the optimal transmission efficiency in high-speed data transmission. It has good frequency usage efficiency and strong characteristics of multi-path fading, so that it is possible to obtain optimal transmission efficiency in high-speed data transmission.

In addition, since the frequency spectrum is superimposed, there is an advantage in that the frequency is efficient, strong in frequency selective fading, and strong in multipath fading. In addition, the protection interval can be used to reduce the influence of Inter Symbol Interference (ISI), it is possible to simply design the equalizer structure in hardware, and has the advantage of being resistant to impulsive noise Therefore, the trend is being actively used in the communication system structure.

1 is a diagram illustrating a transmission apparatus of a general orthogonal frequency division multiplexing system.

Referring to FIG. 1, the transmitting apparatus includes a serial / parallel converter 101, a mapper 103, a subchannel allocator 105, a symbol memory 107, An inverse fast Fourier transform unit (IFFT) 109 may be included.

The serial / parallel converter 101 sequentially outputs the received symbols to L parallel lines according to the number of input taps of the inverse fast Fourier transformers 109.

The mapper 103 maps the input data to corresponding modulation symbols according to a predetermined modulation scheme and outputs the mapping data. The mapper 103 converts the data output of the serial / parallel conversion unit 101 using a mapping table value according to a Modulation and Coding Scheme (MCS) level and a pilot type. In this case, since the value of the mapping table is generally 11 bits or less, the data values of the serial / parallel changer 101 are changed to I / Q data having a bit size of 11 bits or less, respectively, and thus the subchannel allocator. 105 is entered.

The subchannel allocator 105 allocates mapping data received from the mapper 103 to a subcarrier for each symbol. That is, the subchannel allocator 105 processes the data mapped by the mapper 103 to be stored in the symbol memory 107.

The inverse fast Fourier transform unit 109 performs an inverse Fourier transform process by using the value of the mapping data stored in the symbol memory 107 and transfers the RF to the RF terminal.

Unlike other mobile communication systems, the transmitting apparatus of the orthogonal frequency division multiplexing system uses a symbol memory that stores I / Q data having a size of about 11 bits or less and uses one subcarrier mapping unit (eg, IQ, IIQQ, IIIQQQ). The problem of memory wastage when storing I / Q data. In detail, when one mapping unit stores data having IQ, the transmitting apparatus stores information of about 11 bits in size corresponding to I and about 11 bits in size corresponding to Q in each symbol memory. It causes a waste problem.

In addition, due to the above problem, an additional problem occurs that the modem size and power consumption of the modem are increased.

Accordingly, there is a need for an apparatus and method for solving the above-described problems of memory waste and power consumption due to modem size in a transmission apparatus of the orthogonal frequency division multiplexing system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus and method for improving a data rate in a communication system using an orthogonal frequency division multiplexing scheme.

Another object of the present invention is to provide an apparatus and method for reducing power consumption in a transmission apparatus of a communication system using an orthogonal frequency division multiplexing scheme.

It is still another object of the present invention to provide a BPSK, QPSK, 16QAM, 64QAM Modulation and Coding Scheme (MCS) level of data required for a mapping process, and a pilot information of PUSC and BAMC in a transmission apparatus of a communication system using orthogonal frequency division multiplexing. The present invention provides an apparatus and method for performing data transmission using header information and I / Q data.

According to a first aspect of the present invention for achieving the above object, the data transmission device of the mobile communication system is converted to the I / Q data to fit the MCS (Modulation and Coding Scheme) level or data transmission form and stored A serial / parallel converter configured to allocate the I / Q data to a frame to be transmitted, and temporarily store the I / Q data before performing an inverse fast Fourier transform process on the storage location of the I / Q data. A sub-channel allocator for mapping a position of the sub-channel allocator, a header generator for generating a mapping header indicating a format of data allocated to the frame, and temporarily storing the I / Q data with the mapping header and the I / Q data. Characterized in that it comprises a symbol memory.

According to a second aspect of the present invention for achieving the above object, a data transmission method of a mobile communication system is to convert the transmission data into I / Q data to fit the Modulation and Coding Scheme (MCS) level or data transmission form and stored Assigning the I / Q data to a frame to be transmitted, generating a mapping header indicating a format of the data allocated to the frame, and converting a storage location of the I / Q data into an inverse fast Fourier transform process. And mapping the I / Q data to a location of a memory for temporarily storing the I / Q data, and storing the mapping header and the I / Q data at a location of the memory for temporarily storing the I / Q data. Characterized in that.

As described above, the present invention provides a BPSK, QPSK, 16QAM, 64QAM MCS (Modulation and Coding Scheme) level and PUSC, BAMC of data required for a mapping process in a transmission device of a fourth generation wireless mobile communication system that transmits a large amount of data. As the data is transmitted using the header information and the I / Q data indicating the pilot information, the problem of the size of the modem and the power consumption of the modem is solved. As a result, the data rate can be improved.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the following description, an apparatus and method for increasing the data rate of a fourth generation wireless mobile communication system transmitting a large amount of data such as mWiMAX, LTE, WLAN or DMB will be described.

2 is a diagram illustrating a transmission apparatus of an orthogonal frequency division multiplexing (OFDM) system according to an embodiment of the present invention.

Referring to FIG. 2, the transmitting apparatus includes a serial / parallel converter 201, a subchannel allocator 203, a header generator 205, a symbol memory 207, and a mapper. a mapper 209 and an inverse fast Fourier transform unit (IFFT) 211.

First, the serial / parallel conversion unit 201 of the transmitting device converts the data to be transmitted into I / Q data so as to conform to a Modulation and Coding Scheme (MCS) level or a data transmission form and stores the data in each memory. do.

In detail, the serial / parallel conversion unit 201 includes an encoder block, a Ranging Ch, a Channel Quality Indicator (CQI) Ch, and an ACK Ch.

The Encoder block is a block for receiving channel PDU data input from SW and performing channel coding. The encoder block divides the received PDU data by a concatenation rule given for each burst, and includes CTC / CC Encoder, Interleaver, Symbol Selection, After processing to perform the Slot Repetiton function, the result of the execution of the function is stored in the Encoder Output memory included in the Encoder.

The encoder block has QPSK, 16QAM in the encoder output memory. Process to store in the form of IQ, IIQQ, IIIQQQ, which is one mapping unit, each subcarrier according to 64QAM. Herein, the address of the encoder output memory is the maximum number of subcarriers that can be transmitted in one frame at maximum, and the width is at most 6 bits based on 64 QAM.

The Ranging Ch is a channel used for synchronization acquisition, power control, synchronization tracking, handoff, and bandwidth allocation with a base station. The Ranging Ch data randomly selects one code from among sets of codes given for each mode. And generate BPSK modulation.

The channel quality indicator (CQI) Ch is a channel for periodically reporting a response according to the request whenever a request from the base station is provided, and an IQ type having a QPSK form to reduce a transmission error of a code word according to each CQI mode. The codeword information is stored in the memory.

The ACK Ch is a channel used in downlink hybrid automatic retransmission request (HARQ), and can be represented as 1 bit information according to the success or failure of the packet received from the terminal. If the downlink packet is successfully received, the response bit of the ACK channel is represented as '0' (ACK). Otherwise, the response bit is represented as '1' (NAK). To reduce transmission errors, this value is converted to a codeword and stored in memory as IQ in QPSK format.

The subchannel allocator 203 assigns a frame to a transmission data to be transmitted. In detail, the subchannel allocator 203 generates a bitmap for determining a type of data allocated to the frame, and symbol subcarrier mapping for setting a data storage location according to the bitmap in detail. Perform the process.

First, the bitmap generation process of the subchannel allocator 203 will be described. The bitmap generation process receives information necessary for generating a bitmap such as a burst region, a ranging ch region, a CQI region, an ACK region, a zone information, a permutation information, etc. from the SW, and then provides the received information with a symbol axis and It generates two-dimensional map information for each channel (subchannel) axis.

The symbol subcarrier mapping process includes reading address information of data stored in a memory of the serial / parallel converter 201 and data read from a memory of the serial / parallel converter 201. It performs a role of mapping address information to be stored in the symbol memory 207 to each other. In other words, the symbol subcarrier mapping process generates an address of one of several memories of the serial / parallel converter 201 to be allocated to the subchannel by referring to the corresponding symbol and Bitmap information corresponding to the subchannel. And create an address in the symbol memory in which the read data is to be stored. In this case, when the subchannel allocator 203 completes the symbol subcarrier mapping process for all subchannels with respect to one symbol, the subchannel allocator 203 sequentially repeats the symbol subcarrier mapping process for the next symbol.

The header generator 205 uses BPSK, QPSK, 16QAM, and 64QAM MCS (Modulation and Coding Scheme) Level and PUSC of data stored in each subcarrier using the bitmap information generated by the subchannel allocator 203. A mapping header including pilot information of BAMC is generated. In this case, the mapping header does not store a value by a mapping table when storing data stored in the serial / parallel conversion unit 201 in a symbol memory according to the present invention, but stores data before mapping. Therefore, it refers to header information indicating BPSK, QPSK, Modulation and Coding Scheme (MCS) Level of 64QAM, and pilot information of PUSC and BAMC.

The header generation unit 205 is a type of the mapping table of the mapper such as "BPSK => 001, QPSK => 010, 16QAM => 011, 64QAM => 100, PUSC Pilot => 101, BAMC Pilot => 110". Generate the mapping header accordingly.

The mapping header generated by the header generator 205 is located at a location corresponding to a write address of the symbol memory 207 generated by the subchannel allocator 201 together with the I / Q data. Stored. The mapping header and I / Q data stored in the symbol memory 207 may be represented as shown in FIG. Accordingly, the mapping header and I / Q data stored in the symbol memory 207 will be described in detail with reference to FIG. 4.

The mapper 209 checks the mapping header of the data stored in the symbol memory 207 in the order of the data input to the inverse fast Fourier transform unit (IFFT) 211 and processes the data to be mapped to a value according to the mapping table. do. Thereafter, the mapper 209 processes the mapped data to be transferred to the inverse fast Fourier transform unit 211.

The inverse fast Fourier transform unit 211 scrambling and inverse Fourier transforms the mapping data provided from the mapper 209, and attaches a cyclic prefix (CP) to the RF side.

The foregoing has described an apparatus for increasing the data rate of a fourth generation wireless mobile communication system that transmits a large amount of data, such as mWiMAX, LTE, WLAN, or DMB, and in the following description, according to an embodiment of the present invention, mWiMAX, A method for increasing the data rate of a fourth generation wireless mobile communication system that transmits a large amount of data such as LTE, WLAN, or DMB will be described.

3 is a flowchart illustrating a process of transmitting transmission data in a transmission apparatus of an Orthogonal Frequency Division Multiplexing (OFDM) system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the transmission apparatus first checks whether a data transmission event to be transmitted to the receiver is generated in step 301. If the data transmission event does not occur, the transmission apparatus proceeds to step 317 to perform a corresponding function (eg, standby mode).

On the other hand, when the data transmission event occurs, the transmission apparatus proceeds to step 303 and processes the serial / parallel conversion unit 201 to convert the transmission data to be transmitted into I / Q data. The serial / parallel conversion unit 201 converts the transmission data into I / Q data in accordance with a Modulation and Coding Scheme (MCS) level or a data transmission form, and stores the transmission data in each memory.

In step 305, the transmitting apparatus processes the subchannel allocator 203 to allocate the converted I / Q data to a subcarrier, and then proceeds to step 307 to generate a bitmap information. Do it.

Here, the process of generating the bitmap information is a process of generating information required for bitmap generation, such as burst region, raning region, CQI region, ACK region, zone information, permutation information, as two-dimensional map information for each symbol axis and subchannel axis. Say

In step 309, the transmitting apparatus uses the bitmap information generated by the header generation unit 205 to generate a modulation and coding scheme (MCS) of BPSK, QPSK, 16QAM, and 64QAM of data stored in each subcarrier. After processing to generate a mapping header including level, PUSC, and BAMC pilot information, the process proceeds to step 311 and the mapping header generated by the header generation unit 205 together with the I / Q data. The subchannel allocator 203 stores the symbol at a location corresponding to a write address of the symbol memory. Here, the header generation unit 205 maps the mapper as "BPSK => 001, QPSK => 010, 16QAM => 011, 64QAM => 100, PUSC Pilot => 101, BAMC Pilot => 110". The mapping header may be generated according to the type of table.

In operation 313, the transmitter transmits a mapping header of the data stored in the symbol memory 207 in the order of data input to the inverse fast Fourier transform unit (IFFT) 211. After confirming and processing the mapping to the value according to the mapping table, the process proceeds to step 315 to transmit the mapping data mapped by the mapper 209.

Thereafter, the transmitting device ends the present algorithm.

4 is a diagram illustrating a data transmission process of a transmission device according to an embodiment of the present invention.

4 (a) is a diagram illustrating an operation process of a transmitting apparatus according to an exemplary embodiment of the present invention.

Referring to FIG. 4 (a), the serial / parallel converter converts data to be transmitted into I / Q data in accordance with a Modulation and Coding Scheme (MCS) level or a data transmission form and stores the data in each memory. As described above with reference to FIG. 2, the serial / parallel conversion unit uses the QPSK, 16QAM. IQ according to 64QAM. IIQQ. It is stored in memory in the form of IIIQQQ, Ranging Ch uses Ranging Seed information, BPSK type, and CQI Ch uses Code Word information written by SW. The IQ type and the ACK Ch in the QPSK form are stored in the IQ form in the QPSK form by using HARQ Burst information of Down | ink.

The subchannel allocator receives information necessary for generating a bitmap such as a burst region, a ranging ch region, a CQI region, an ACK region, zone information, permutation information, and the like, and then supplies the received information to a symbol axis and a subchannel. To generate two-dimensional Map information for each axis, and store address information (Read Address) of data stored in the memory of the serial / parallel conversion unit and data read from the memory of the serial / parallel conversion unit in the symbol memory. Map Address Information.

The header generator includes BPSK, QPSK, 16QAM, 64QAM MCS (Modulation and Coding Scheme) Levels of data stored in each subcarrier, and pilot information of PUSC and BAMC, using the bitmap information generated by the subchannel allocator. After generating a mapping header, the mapping header and the I / Q data are stored in a location corresponding to a write address of the symbol memory generated by the subchannel allocator. Here, the transmitting apparatus may store the mapping header and the I / Q data in the symbol memory as shown in FIG. 4 (b). In FIG. 4, the header generating unit is included in the symbol memory. do.

Referring to FIG. 4B, "001" of the mapping header means BPSK and I / Q data means 1 bit of data (I). In the same way, "100" of the mapping header means 64QAM, and I / Q data means 6-bit data (IIIQQQ).

The mapper checks the mapping header of the data stored in the symbol memory in the order of the data input to the inverse fast Fourier transform (IFFT) block and processes the mapping header into a value according to the mapping table. Thereafter, the mapper processes the mapped data to be transferred to the inverse fast Fourier transform unit, and the inverse fast Fourier transform unit scrambling and inverse Fourier transforms the mapping data provided from the mapper and attaches the CP to the RF.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a diagram illustrating a transmission apparatus of a general orthogonal frequency division multiple access system;

2 is a diagram illustrating a transmission apparatus of an orthogonal frequency division multiplexing system according to an embodiment of the present invention;

3 is a flowchart illustrating a data transmission process of a transmission apparatus according to an embodiment of the present invention;

4 (a) is a view showing an operation process of a transmitting apparatus according to an embodiment of the present invention;

4B is a diagram illustrating a format of the mapping header and the I / Q data according to an embodiment of the present invention.

Claims (6)

In the data transmission device of a mobile communication system, A serial / parallel conversion unit for converting and storing transmission data into I / Q data so as to conform to a Modulation and Coding Scheme (MCS) level or a data transmission type; Subchannel allocation for allocating the I / Q data to a frame to be transmitted and mapping the storage location of the I / Q data to a location of a memory for temporarily storing the I / Q data before performing an inverse fast Fourier transform process. Wealth, A header generation unit for generating a mapping header indicating a format of data allocated to the frame; And a symbol memory for temporarily storing the mapping header and the I / Q data. The method of claim 1, The data transmission device of the mobile communication system, A mapper that maps according to a mapping table value using the mapping header stored in the symbol memory; And an inverse fast Fourier transform unit for performing the inverse fast Fourier transform on the mapped data. The method of claim 2, The header generation unit, Device for generating the mapping header as shown in Table 1 below. BPSK 0 0 One QPSK 0 One 0 16QAM 0 One One 64QAM One 0 0 PUSC Pilot One 0 One BAMC Pilot One One 0 In the data transmission method of the mobile communication system, Converting and storing the transmission data into I / Q data in accordance with a Modulation and Coding Scheme (MCS) level or a data transmission type; Assigning the I / Q data to a frame to be transmitted and generating a mapping header indicating a format of data allocated to the frame; Mapping the storage location of the I / Q data with a location of a memory for temporarily storing the I / Q data before performing an inverse fast Fourier transform process; And storing the mapping header and the I / Q data in a location of a memory for temporarily storing the I / Q data. The method of claim 4, wherein The data transmission method of the mobile communication system, Storing the mapping header and the I / Q data in a location of a memory for temporarily storing the I / Q data, and then mapping the I / Q data according to a mapping table value using information of the mapping header; , And performing the inverse fast Fourier transform on the mapped data. The method of claim 5, The mapping header, It can be defined as shown in Table 2 below. BPSK 0 0 One QPSK 0 One 0 16QAM 0 One One 64QAM One 0 0 PUSC Pilot One 0 One BAMC Pilot One One 0

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