KR102549055B1 - Rate matching method and apparatus, and method and apparatus for transmitting and receiving signal - Google Patents

Abstract

The transmitter converts a first code block included in a transport block into a plurality of first modulation symbols. The transmitter converts a second code block included in the transport block into a plurality of second modulation symbols. The transmitter sequentially maps each of the first modulation symbols to each of REs corresponding to a first time domain symbol among a plurality of resource elements (REs) included in an allocated resource. The transmitter sequentially maps each of the second modulation symbols to each of REs corresponding to a second time domain symbol next to the first time domain symbol among a plurality of resource elements included in the allocated resource.

Description

Rate matching method and device, and signal transmission and reception method and device

The present invention relates to a method and apparatus for rate matching.

The present invention also relates to a method and apparatus for transmitting and receiving signals.

The baseband modem signal may be delivered as user data through demodulation and decoding processes. When channel noise is included in data in a radio channel interval, if the error is not corrected during demodulation and decoding of the corresponding data, the receiver must report the error to the transmitter and receive retransmission of the corresponding data.

When a transmitter transmits data, such as a physical downlink shared channel (PDSCH) transmission method of the 3rd generation partnership project (3GPP)-long term evolution (LTE) standard, a turbo coding method is used, which causes a significant delay in decoding processing time. Occurs.

As the error reporting according to the delay time is delayed, the retransmission time is also delayed in proportion thereto. This delay time increases by a multiple of a transmission time interval (TTI), which is a transmission unit time, and thereby causes a bottleneck phenomenon in a mobile communication system requiring a high-speed response.

In particular, unlike voice signals, for use in remote medical control and industrial precision control systems that require fast response, data transmission delay time must be reduced. To this end, a task of improving a frame structure in which the TTI transmission unit time is reduced is in progress by the 3GPP standardization organization, which is an international standardization organization. For example, by shortening a TTI having 2 slot times (eg, 14 orthogonal frequency division multiplexing (OFDM) symbol interval times) on the time axis, the TTI has a time of 1 slot or less A modification is in progress. However, this does not end with modifying only the transmission frame structure, and the following problems exist.

A decrease in the time axis for TTI reduction may cause an increase in the frequency axis. That is, as much as the TTI time is reduced, resource allocation in the frequency axis is inevitably increased, and as a result, the demodulation time and the decoding time delay are not different from before. Also, demodulation may be performed in units of OFDM symbols, but decoding is possible only when the output of demodulation is performed in units of code blocks. Therefore, since the throughput units of demodulation and decoding are different, delay occurs according to blank time.

An object of the present invention is to provide a method and apparatus for reducing demodulation and decoding processing time of a mobile communication modem.

Another problem to be solved by the present invention is to provide a method and apparatus for transmitting whether there is an error in downlink data within the same subframe through a time-divided uplink without delay.

According to an embodiment of the present invention, a transmission method of a transmitter is provided. The transmission method of the transmitter may include converting a first code block included in a transport block into a plurality of first modulation symbols; converting a second code block included in the transport block into a plurality of second modulation symbols; sequentially mapping each of the first modulation symbols to each of REs corresponding to a first time domain symbol among a plurality of resource elements (REs) included in an allocated resource; and sequentially mapping each of the second modulation symbols to each of REs corresponding to a second time domain symbol next to the first time domain symbol among a plurality of resource elements included in the allocated resource.

The transmission method of the transmitter may include, before the step of converting into a plurality of first modulation symbols, determining the size of the transport block and the size of the first code block according to the size of the allocated resource; and dividing the transport block into a plurality of code blocks including the first code block and the second code block.

The converting into a plurality of first modulation symbols may include turbo encoding the first code block to generate a first bit stream; generating a second bit string having an effective code rate by rate matching the first bit string; and converting the second bit stream into the plurality of first modulation symbols through modulation symbol mapping.

Each of the first time domain symbol and the second time domain symbol may be an orthogonal frequency division multiplexing (OFDM) symbol.

The allocated resources may include 84 REs corresponding to 7 OFDM symbols on the time axis and 12 subcarriers on the frequency axis.

Also, according to another embodiment of the present invention, a receiving method of a receiver is provided. The receiving method of the receiver may include: completing reception of first data corresponding to a first code block during a time of a first time domain symbol among a plurality of time domain symbols belonging to a first allocation resource; demodulating the first data; and completing decoding of the demodulated first data within a time of a second time domain symbol following the first time domain symbol among a plurality of time domain symbols belonging to the first allocation resource.

The demodulating of the first data may include inputting the first data to an FFT processor for fast Fourier transform (FFT).

When the input of the first data to the FFT processor is completed, an FFT result of the first data may start to be output from the FFT processor.

The demodulating of the first data may further include outputting a log likelihood ratio (LLR) by symbol demapping an FFT result of the first data.

The receiving method of the receiver may include completing reception of second data corresponding to a second code block during the time of the second time domain symbol; demodulating the second data; and completing decoding of the demodulated second data within a time of a third time domain symbol following the second time domain symbol among a plurality of time domain symbols belonging to the first allocation resource. .

The first code block and the second code block may be included in one transport block.

The receiving method of the receiver may further include transmitting error information indicating whether an error exists in the first data to a transmitter that has transmitted the first data within an uplink period of a first subframe.

Completing reception of the first data may include receiving the first data within a downlink period of the first subframe.

The uplink period of the first subframe may start when the time of one time domain symbol has elapsed based on the end of the downlink period of the first subframe.

Also, according to another embodiment of the present invention, a transmission method of a transmitter is provided. The transmission method of the transmitter may include dividing a first code block among a plurality of code blocks included in a transport block into a plurality of packets; converting a first packet among the plurality of packets into a plurality of first modulation symbols; converting a second packet among the plurality of packets into a plurality of second modulation symbols; sequentially mapping each of the first modulation symbols to each of REs corresponding to a first time domain symbol among a plurality of resource elements (REs) included in a first allocation resource; and sequentially mapping each of the second modulation symbols to each of REs corresponding to a second time domain symbol next to the first time domain symbol among a plurality of resource elements included in the first allocation resource. do.

The dividing into the plurality of packets may include dividing the transport block into the plurality of code blocks; generating a first bit stream by turbo encoding the first code block; and generating the plurality of packets according to a hybrid automatic repeat request (HARQ) redundancy version (RV) by rate matching the first bit string.

A total length of the plurality of packets may be equal to a length of the first bit string.

The size of the first packet and the size of the second packet may be different from each other.

The transmission method of the transmitter may further include receiving error information indicating whether the first code block is normally transmitted within the downlink period of the first subframe within the uplink period of the first subframe. there is.

According to an embodiment of the present invention, in a subframe structure in which a TTI includes at least one OFDM symbol on the time axis, demodulation and decoding can be performed in units of OFDM symbols, and a gap according to processing time can be eliminated, resulting in delay time. can be reduced, and low-delay decoding can be performed.

In addition, according to an embodiment of the present invention, an ACK or NACK result for received data can be transmitted without delay within the same subframe, thereby configuring a self-contained type time division duplexing (TDD) subframe can do.

In addition, according to an embodiment of the present invention, an effect of transmitting a hybrid automatic repeat request (HARQ) bundling packet of an IR (incremental redundancy) method between OFDM symbols within a TTI can be obtained.

In addition, according to an embodiment of the present invention, a low-delay system specification can be enabled by modifying the rate matching specification of the 3GPP-LTE International Standard Organization, and compatibility with the existing rate matching specification can be maintained.

1 is a diagram illustrating a method in which a transmitter allocates modulation symbols to resource elements (REs) according to an embodiment of the present invention.
2 is a diagram illustrating a method in which a receiver performs demodulation and decoding processing in units of OFDM symbol intervals according to an embodiment of the present invention.
3 is a diagram illustrating a structure of a self-contained type TDD frame according to an embodiment of the present invention.
4 is a diagram illustrating a method in which a transmitter allocates one code block to REs of multiple OFDM symbols according to an embodiment of the present invention.
5 is a diagram illustrating a transmitter according to an embodiment of the present invention.
6 is a diagram illustrating a receiver according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Meanwhile, in the present specification, 'A or B' may include 'A', 'B', or 'both A and B'.

1 is a diagram illustrating a method in which a transmitter allocates modulation symbols to resource elements (REs) according to an embodiment of the present invention.

In order to enable the receiver to perform demodulation and decoding together in units of time domain symbols (eg, OFDM symbols), the transmitter has physical resources such that the boundaries of the time domain symbols (eg, OFDM symbols) are matched with the boundaries of the code blocks. (eg, RB (resource block)) is mapped.

1 illustrates a case in which resource allocation is performed within one RB (ie, a case in which the size of allocated resources is the size of one RB).

개(예, 7개)의 OFDM 심볼을 포함하고, 주파수 축으로

개(예, 12개)의 부반송파를 포함한다. 예를 들어, 하나의 RB는 84개(=7x12)의 RE를 포함할 수 있다. 본 명세서에서는 하나의 RB에 속하는 7개의 OFDM 심볼을 OFDM 심볼 0번 내지 6번이라 하고, 하나의 RB에 속하는 12개의 부반송파를 부반송파 x번 내지 x+11번 이라 한다. 또한 본 명세서에서는 부반송파 k번에 대응하며 OFDM 심볼 l번에 대응하는 RE를, RE(k, l)라 한다. 예를 들어, RE(x+3, 5)는 부반송파 x+3번에 대응하며 OFDM 심볼 5번에 대응하는 RE를 나타낸다. Specifically, one RB is the time axis

(eg, 7) OFDM symbols, and in the frequency axis

(eg, 12) subcarriers. For example, one RB may include 84 (=7x12) REs. In this specification, 7 OFDM symbols belonging to one RB are referred to as OFDM symbols 0 to 6, and 12 subcarriers belonging to one RB are referred to as subcarriers x to x+11. Also, in this specification, an RE corresponding to subcarrier k and corresponding to OFDM symbol l is referred to as RE(k, l). For example, RE(x+3, 5) corresponds to subcarrier x+3 and represents an RE corresponding to OFDM symbol number 5.

Meanwhile, the size of a transport block (TB) and the size of a code block (CB) (or codeword length) are determined according to the size of the allocated resource (eg, the size of one RB) . Specifically, the transport block (TB) is divided into a number of code blocks (CB). Each code block (CB) is coded using the 1/3 turbo coding method.

The coded bit stream (or codeword) is punctured again through rate matching to have an effective coding rate.

The rate-matched codeword is mapped to an allocated resource size (eg, RB size) by symbol mapping according to a modulation scheme (eg, QPSK, 16QAM, or 64QAM). Hereinafter, a case in which the QAM modulation scheme is used will be described as an example. At this time, the boundary of the OFDM symbol coincides with the boundary of the rate-matched codeword of each code block (CB).

Encoded and rate-matched bits of a first code block (CB) among a plurality of code blocks (CB) are converted into modulation symbols.

Each modulation symbol is mapped to an RE of an RB. Specifically, modulation symbols corresponding to the first code block (CB) are sequentially mapped from RE(x+11, 0) corresponding to OFDM symbol 0 of the RB to RE(x, 0). Similarly, modulation symbols corresponding to the second code block (CB) are sequentially mapped from RE(x+11, 1) corresponding to OFDM symbol 1 of the RB to RE(x, 1). In the same way, modulation symbols of the code block (CB) are mapped to REs until the last OFDM symbol (eg, OFDM symbol 6) section of the TTI.

2 is a diagram illustrating a method in which a receiver performs demodulation and decoding processing in units of OFDM symbol intervals according to an embodiment of the present invention.

The receiver demodulates and decodes received data in units of OFDM symbol intervals within an allocated resource interval (RB interval).

Specifically, as a first step, the receiver completes data reception during one OFDM symbol interval. For example, the receiver may complete receiving data corresponding to one code block (CB) during OFDM symbol interval 0, and receive data corresponding to another code block (CB) during OFDM symbol interval 1. can be completed

As a second step, the receiver inputs the received data to the FFT processor for fast Fourier transform (FFT) processing on the received data.

As a third step, the receiver starts outputting the FFT operation result at the time when data of one OFDM symbol interval is input. For example, the receiver starts outputting an FFT operation result for data of OFDM symbol interval 0 when all data received during OFDM symbol interval 0 is input to the FFT processor. The receiver outputs a log likelihood ratio (LLR) by performing an inverse process of QAM symbol mapping (eg, symbol demapping) on the FFT output.

As a fourth step, the receiver decodes the LLR output.

Each of the above-described steps may be continuously processed, and the receiver may perform decoding in units of OFDM symbol intervals.

Meanwhile, the decoding process may be completed within the same OFDM symbol as the decoding start point or within the next OFDM symbol period, depending on the location of allocated resources. For example, as illustrated in FIG. 2 , decoding of data received in OFDM symbol interval 0 may be completed within OFDM symbol interval 1. That is, data received during OFDM symbol interval 0 can be input to the FFT processor during OFDM symbol interval 0, and FFT output, QAM demodulation, and decoding are completed during OFDM symbol interval 1 for the data input to the FFT processor. It can be. Alternatively, decoding of data received in OFDM symbol interval 1 may be completed within OFDM symbol interval 2.

3 is a diagram illustrating a structure of a self-contained type TDD frame according to an embodiment of the present invention.

According to the method described in FIGS. 1 and 2 , data transmission in a time division duplexing (TDD) frame structure of a self-contained or stand-alone type is possible. Here, the self-contained TDD frame structure is a frame structure in which a downlink period TI1 and an uplink period TI2 coexist within the same subframe.

The receiver may transmit to the transmitter a result of whether there is an error in the downlink data within the same subframe as the subframe in which the downlink data is received. Here, the subframe is a subframe in which code block (CB) data described in FIGS. 1 and 2 is transmitted and received, and may include an allocated resource (eg, RB).

Specifically, the receiver may transmit ACK or NACK indicating an error result for the downlink data received in the downlink interval (TI1) in the uplink interval (TI2) following the GAP (eg, one OFDM symbol interval). .

On the other hand, as illustrated in FIG. 1, when one code block (CB) is mapped to one OFDM symbol, since decoding of received data can be processed in units of OFDM symbols, blank time between demodulation and decoding this doesn't happen

Meanwhile, there is a case where one code block (CB) spans multiple OFDM symbols. This will be described with reference to FIG. 4 .

4 is a diagram illustrating a method in which a transmitter allocates one code block to REs of multiple OFDM symbols according to an embodiment of the present invention.

When one code block (CB) spans a plurality of OFDM symbols, the corresponding code block (CB) is separated into packet units according to HARQ redundancy version (RV).

Each separated packet is encoded by the 1/3 turbo encoding method illustrated in FIG. 1, and the encoded bit stream is stored in a circular buffer. At this time, bit strings stored in the circular buffer are selected to have four different starting points and sizes.

When one code block (CB) is mapped to multiple OFDM symbols, the corresponding code block (CB) is divided into different packets and mapped to multiple OFDM symbols. Here, the size of each packet may be the same or different. Packets mapped to different OFDM symbols have an HARQ bundling transmission effect. The number of bundling may vary from 1 to 4.

In FIG. 4, a case in which one code block (CB) spans four OFDM symbols (numbers 0 to 3) is illustrated. In addition, FIG. 4 illustrates a case in which resource allocation is performed within one RB (ie, a case in which the size of allocated resources is the size of one RB).

A transport block (TB) is divided into a number of code blocks (CB). Each code block (CB) is coded using the 1/3 turbo coding method.

The coded bit stream is punctured through rate matching to have an effective code rate. Specifically, assuming that the effective code rate is 1/3, since puncturing does not need to be performed in rate matching, the length of the rate matching result (eg, the total length of packets generated by rate matching) is coded bits equal to the length of the column

After the rate matching result is mapped to modulation symbols, it is mapped to REs of allocated resources (eg, RBs). As a result, as illustrated in FIG. 4 , four HARQ bundling packets that can be generated by rate matching may include RV0, RV1, RV2, and RV3.

Modulation symbol groups Sg0, Sg1, Sg2, and Sg3 corresponding to RV0, RV1, RV2, and RV3 are mapped to different OFDM symbols. For example, modulation symbols of the modulation symbol group Sg0 are sequentially mapped from RE(x+11, 0) to RE(x, 0) corresponding to OFDM symbol 0 of an allocated resource (eg, RB). And, the modulation symbols of the modulation symbol group Sg1 are sequentially mapped from RE(x+11, 1) to RE(x, 1) corresponding to OFDM symbol No. 1 of the allocated resource (eg, RB). And, the modulation symbols of the modulation symbol group Sg2 are sequentially mapped from RE(x+11, 2) to RE(x, 2) corresponding to OFDM symbol No. 2 of the allocated resource (eg, RB). And, the modulation symbols of the modulation symbol group (Sg3) are sequentially mapped from RE(x+11, 3) to RE(x, 3) corresponding to OFDM symbol No. 3 of the allocated resource (eg, RB).

Meanwhile, when the receiver receives data configured as illustrated in FIG. 4 , a demodulation and decoding method for the received data is the same as the receiving method described in FIG. 2 .

Demodulation and decoding are performed in units of OFDM symbol intervals. Specifically, the receiver completes reception of data corresponding to one of the four packets (RV0 to RV3) belonging to one code block (CB) during one OFDM symbol period, and demodulation and decoding thereof can be performed. For example, the receiver may complete reception of data corresponding to the packet RV0 (ie, data corresponding to the modulation symbol group Sg0) during OFDM symbol interval 0, and demodulate and decode the received data.

However, in FIG. 4, since the same TB (specifically, one code block (CB) belonging to the TB) data is divided into four different packets, when the receiver performs decoding in units of OFDM symbols, the effective coding rate ) is lowered. This is the same as the receiver performing the HARQ process using new data indication (NDI).

5 is a diagram illustrating a transmitter according to an embodiment of the present invention.

The transmitter 100 includes a processor 110, a memory 120, and a radio frequency (RF) converter 130.

Processor 110 may be configured to implement functions, procedures, and methods described herein with respect to transmitters. Also, the processor 110 may control each component of the transmitter 100 .

The memory 120 is connected to the processor 110 and stores various information related to the operation of the processor 110 .

The RF converter 130 is connected to the processor 110 and transmits or receives a radio signal.

The transmitter 100 may correspond to a base station or a terminal.

6 is a diagram illustrating a receiver according to an embodiment of the present invention.

The receiver 200 includes a processor 210, a memory 220, an RF converter 230, and an FFT processor 240.

Processor 210 may be configured to implement functions, procedures, and methods described herein with respect to a receiver. Also, the processor 210 may control each component of the receiver 200 .

The memory 220 is connected to the processor 210 and stores various information related to the operation of the processor 210 .

The RF converter 230 is connected to the processor 210 and transmits or receives a radio signal.

FFT processor 240 may perform the functions, procedures, and methods described herein with respect to FFT processing of received signals.

The receiver 200 may correspond to a terminal or a base station.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention. that fall within the scope of the right.

Claims (18)

delete delete delete delete receiving first data in all resource elements within a first time domain symbol;
receiving second data from all resource elements within a second time domain symbol neighboring the first time domain symbol;
demodulating and decoding the first data while receiving the second data;
demodulating and decoding the second data when all of the second data is received during the second time domain symbol; and
When the first data and the second data are different redundancy versions (RVs) for the same code block, the first data corresponding to the first time domain symbol corresponds to the second time domain symbol Demodulation and decoding are performed in time, and second data corresponding to the second time domain symbol is demodulated and decoded in time corresponding to a third time domain symbol, and the third time domain symbol is demodulated and decoded at the second time domain symbol. A reception method of a receiver neighboring a domain symbol. delete delete delete delete delete delete encoding one of the plurality of code blocks divided from the transport block using a turbo code;
generating a plurality of modulation symbol groups by performing rate matching on bits of one encoded code block;
mapping a first modulation symbol group among the plurality of modulation symbol groups to all resource elements within a first orthogonal frequency division multiplexing (OFDM) symbol;
mapping a second modulation symbol group among the plurality of modulation symbol groups to all resource elements within a second OFDM symbol;
including,
The first modulation symbol group corresponds to a first RV among a plurality of redundancy versions (RVs) belonging to the code block, and the second modulation symbol group corresponds to a second RV among the plurality of RVs; A transmission method of a transmitter, wherein a second OFDM symbol is adjacent to the first OFDM symbol. According to claim 12,
Generating a plurality of modulation symbol groups by performing rate matching on the bits of the coded code block,
Generating the plurality of modulation symbol groups so that modulation symbols in one of the plurality of modulation symbol groups can be mapped to all resource elements.
Transmitting method of a transmitter comprising a. delete delete According to claim 12,
Wherein the first OFDM symbol and the second OFDM symbol include 12 REs corresponding to 12 subcarriers on the frequency axis.
delete delete

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