KR20020036373A - Data Rate Matching Method in 3GPP2 - Google Patents

Abstract

PURPOSE: A method for matching a data rate in the 3rd generation partnership part 2 system is provided to embody a low valid code rate on a channel environment for regulating a length of a spreading factor or a channel interleaver designated in a negotiation in a normal data rate mode, a variable data rate mode, or a multi data rate mode. CONSTITUTION: In an input information bit column of a channel coder, a CRC bit having a predetermined length for detecting an error is added to a channel bit at a CRC bit block(S20). After the CRC bit is added, a tail bit or reserved bits are appended in the bit column(S21). In case that a chain which is not a normal data rate regulated in a wireless structure is formed using a turbo code, a channel coding is performed using a turbo coder of 1/Kn rate as a channel coder(S22). An output of the channel coder uses a rate matching puncturing(5I>N) or a rate matching repetition(5I<N) for a matching between (Kn X 1) and a channel interleaver size N(S23). The Kn is an inverse value of the turbo code rate and is fixed in one value out of {2,3,4,5}. A method for deciding the turbo code rate is decided according to a ratio between a length of an information input bit column of the channel coder and the size N of the channel interleaver.

Description

Data Rate Matching Method in Next Generation Mobile Communication System

The present invention relates to the next generation of mobile communications, particularly when the transmission chain is formed to support higher coding gains in variable or variable data rate modes for information bit streams having arbitrary data rates. The present invention relates to a data rate matching method in a next generation mobile communication system that can be compatible with a puncturing pattern of data rates.

In general, in addition to the normal data rate mode, there are two transmission modes in the data transmission mode of the next generation mobile communication (hereinafter, referred to as 3GPP2), a variable data rate mode and a multivariate data rate mode.

The normal data rate mode refers to a transmission mode that operates on a fixed chain called a radio configuration (hereinafter referred to as RC).

RC can be thought of as a type of transmission chain in which the length of the information data, the length of the channel interleaver, and the length of the output string of the channel encoder according to the code rate of the channel code are matched. At this time, there is a formal rule between the length of the channel interleaver, the coding rate of the channel encoder, and the length of the Walsh code of the channel.

In other words, when the chip rate to be used is determined, the number of chips into one modulation symbol is determined according to the length of the channel interleaver, which can be defined as a spreading factor. The length of the Walsh code that can code multiplex the channels is determined.

At this time, the number of available Walsh codes is in proportion to the length of the Walsh code. Accordingly, the number of channels that can be accommodated in the multiplexing chain varies according to the Walsh code.

Consider the length after channel coding for input information bits having the same length. In this case, the ability of an error correction code to correct an error that may occur in a channel is stronger as the coding rate of the channel encoder is lower.

In other words, the lower the coding rate of the channel encoder is, the better the error correction capability is, and thus the lower the transmission power can be used. However, when a channel coder having a low code rate is used, the length of the output string of the channel encoder is increased, thereby increasing the length of the channel interleaver.

This results in an increase in the modulation symbol rate, thereby reducing the number of chips entering one modulation symbol at a fixed chip rate.

This results in a reduction in the number of useful Walsh codes.

On the contrary, if the channel coding technique of high coding rate is used for the input string of the same length channel encoder, the error correction capability is reduced but the length of the output string of the channel encoder is shortened. Length of channel interleaver may be used, resulting in an increase in the number of Walsh codes that may be useful.

As described herein, it can be seen that there is a trade-off relationship between the coding rate of the channel encoder and the Walsh code space. Considering this trade-off relationship, RC can be thought of as a formalization of a transmission chain that can be used to secure Walsh code space, or a transmission chain that can be used when lower transmission power is required. .

Currently, 3GPP2 defines several RCs for 1X systems using a chip rate of 1.2888Mcps and some formal RCs for 3X systems using a chip rate of 3.6864Mcps.

One thing to note here is that the spreading factor has an exponential value of 2, so that the input data rate and the length of the interleaver defined in each RC are also increased by twice.

Before the traffic channel is established between the terminal and the base station, the terminal and the base station determine the RC to be used through the negotiation process and the length of the spreading factor on each RC, that is, the channel interleaver, and the communication process proceeds according to the chain.

The modes of using a transmission chain other than the transmission chain defined on the RC are the variable data rate mode and the multivariate data rate mode.

Variable data rate mode is a transmission method that can support any data rate in addition to the standard data rate supported by each RC. This variable data rate was introduced to support Adaptive Multi-Rate (hereinafter abbreviated as AMR) codec, which is one of the 3GPP speech codecs on the physical layer of 3GPP2.

That is, in the case of AMR, data bits that do not match the standard data rate supported by each RC of 3GPP2 can be dropped during the frame period for 20ms.

Next, there is what is called a multivariate data rate mode. The purpose of this mode is to:

In the 3GPP2 system, the base station schedules transmission on the forward auxiliary channel. At this time, the base station allocates a fixed data rate to the terminal through a message.

However, the channel situation between the base station and the specific terminal may change during that particular time, and the system load of the base station may also change.

For example, as the terminal moves away from the base station, the situation of the channel may change, and the channel environment may deteriorate, and thus, the base station may not have sufficient transmit power for transmitting at a current data rate to a specific terminal.

To solve this problem, the base station may stop transmitting to the auxiliary channel during this time. This solution, however, causes delays in data transmission and can also cause unnecessary waste of useful transmission power and Walsh codes.

Another solution is to consider how the base station reschedules the transmission data rate after a certain amount of time. However, this also causes problems such as time delay and waste of Walsh code.

This situation is not unique to the forward link. Similarly, even in the reverse link, the state of the channel between the terminal and the base station may change according to the movement of the terminal, and thus, there may be a lack of transmission power for maintaining proper quality.

Thus, a mode called multivariate data rate has been used to solve this situation. In this mode, the transmission rate is changed in units of frames depending on the situation. That is, when it is determined that the channel environment is deteriorated, the base station lowers the transmission rate of the auxiliary channel. If it is determined that the channel environment is recovered again, it can be considered that the transmission mode is performed again at the previous transmission rate. Using this multivariate data rate mode, the base station can use the power available at the base station without frequent rescheduling.

In order to support the variable data rate mode and the variable data rate mode, each RC of 3GPP2 currently configures a transmission chain using the following method.

As described above, the length of the channel interleaver used in each RC is determined according to the spreading factor. At this time, since the spreading factor has a value increasing in the form of an exponential power of 2, the length of the interleaver determined for a certain spreading factor and the length of the interleaver determined for the spreading factor one step lower than that is exactly 1: 2. Will have a relationship with

In this case, let the large spreading factor A be the small spreading factor B. Then, in each RC, a 1: 1 mapping relationship is established between the spreading factor and the information bit string input to the channel encoder. If the length of the information bit string input to the channel encoder for the spreading factor A is I _A , and the length of the information bit string input to the channel encoder for the spreading factor B is I _B , then I _B = 2 * I _A Will have a relationship with Also, if the length of each channel interleaver to be used is N _A and N _B , there will be a relationship of N _B = 2 * N _A.

At this time, I (i.e., S10 and S11) satisfying the relation of "I _A <I <I _B " rather than the length of the data to be normalized. The coding rate of the channel encoder (using the turbo code or the convolutional code) used in the current RC as shown in FIG. 1 in consideration of the variable data rate or the multivariate data rate mode, the length of which is the length of the input string of the channel encoder. Assuming this is 1 / n, the output of "n * I" will be sent for the input of I. (S12)

At this time, the relationship of "N _A <n * I <N _B " is satisfied. Therefore, some work is required to match the length "n * I" of the output string of the channel encoder to the interleaver length.

The current approach taken by 3GPP2 is to match the length L (= n * I) of the output string of the channel encoder to the interleaver of N = N _B. Accordingly, bit repetition as much as "N _B -n * I" is performed. (S13) A method of performing this performs a uniform repetition process as follows.

That is, the kth output symbol of the repeating block is for index k that increases from 0 to N-1. It can be estimated from the code symbols of the first input bit string.

Next, a method for supporting the multivariate data rate mode will be described.

In multivariate data rate mode, the maximum data rate, one level lower data rate, and two levels lower data rate that can be supported during the initial negotiation process are defined as a set of transmission data rates.

Therefore, in the multivariate data rate mode for the current auxiliary channel, the data rate of the auxiliary channel is adjusted between the support rate up to two levels below. At this time, if the forward channel is considered, the terminal must determine the rate variation through the blind rate detection. Accordingly, if the data transmission rate is too large, a problem arises that increases the complexity of the terminal.

The length of the channel interleaver and the Walsh code used at the maximum data rate should not be changed. In other words, the interleaver and Walsh codes specified for the maximum transmission rate currently used are used as they are.

Therefore, if the data rate is lowered to 1/2 of the maximum rate, the symbol repetition is doubled to match the length of the interleaver to be used in the channel and the length of the output string of the channel encoder.

Similarly, if the data rate is lowered to 1/4 of the maximum data rate, four times symbol repetition is performed to match the length of the interleaver to be used in the channel and the length of the output string of the channel encoder.

The previous example is an example of a variable data rate in the secondary channel of the forward channel.

Multivariate data rate modes for variable data rates may be supported in the secondary channel.

In this case, however, the definitions of the variable data rate and the multivariate data rate mode are blurred. In other words, even if the maximum data rate in the multivariate data rate mode is the normal rate set on the current RC, and the data rate one step lower is the data rate set on the current RC, the data is actually already one step lower. The rate can also be seen as a variable data rate that does not use a chain defined on the current RC. This is because the length of the interleaver, that is, the spreading factor, in the multivariate data rate mode is fixed at that of the maximum transmission rate.

As an example, consider the RC4 of the current forward channel. At this time, a half rate turbo code or a convolution code is used. Assume that the maximum data rate that can be used in the multivariate data rate mode is 76.8 kbps. At this time, the length of the interleaver used in the forward RC4 is fixed to 3072. Consider a multivariate data rate method in this mode. Assume that the available data rate is used at an appropriate value among the set of {19.2 kbps, 38.4 kbps, 76.8 kbps}. The data rates of 38.4 kbps and 19.2 kbps are clearly defined at RC4, but the problem is that there is no chain connecting these rates at 3072, the length of the current interleaver on this RC. As a result, this rate can also be viewed as a variable data rate.

As a result, if the length of the interleaver is fixed to N even in the multivariate data rate mode, and the data rate being transmitted is not defined on the current RC, the output of the channel encoder through the uniform iteration algorithm described above You can match the length of a row to the length of a given interleaver.

That is, the variable data rate and the variable data rate should be considered in the same context, and a method for supporting this on each RC can be described through the chain as shown in FIG. 1.

However, the conventional method for supporting the variable data rate mode and the multivariate data rate mode is that the concept of the RC is ambiguous in the concept of the variable data rate mode and the multivariate data rate mode. As mentioned above, the concept of RC can be thought of as a formal rule that defines the relationship between the coding rate and the spreading factor of a channel encoder. However, in the variable data rate mode or the multivariate data rate mode, this relationship does not hold as a formal rule in the RC. That is, when the desired spreading factor is determined and the length of the channel interleaver to be used is determined, and the length of the input string to the channel encoder is determined, the channel encoding is performed according to the coding rate currently used on the RC. In addition, the symbol repetition process is performed for the code symbols to match the length of the predetermined interleaver.

In other words, in such a variable data rate mode and a multivariate data rate mode, the formal relationship on RC is lost between the coding rate and the spreading factor of the channel encoder.

In the current method, a matching process with a specific spreading factor is performed by repeating the code symbol as described above.

One thing to note here is that the effective code rate is the ratio of the length N of the interleaver to the length I of the information bit string input to the channel encoder. Assuming that the code rate defined on each RC is 1 / n, then on any other data rate except the chain normalized on the RC in either the variable data rate mode or the multivariate data rate mode: Will have a relationship.

<

In other words, in the variable data rate mode or the multivariate data rate mode, it means that the effective code rate is lowered, and that it is used repeatedly for the matching process with the interleaver. This means that the effective code rate is reduced, but the actual code rate is still 1 / n specified on RC.

Therefore, it can be considered that both the current variable data rate mode and the multivariate data rate mode have a problem in that a gain that can be obtained on the transmission power is lost through an increase in the coding gain due to a decrease in the coding rate.

That is, if the length of the interleaver is set to a certain value, and the transmission rate of the data to be transmitted currently is determined, the coding rate for obtaining the maximum coding gain is selected according to the relationship between the two. There is a need to construct a new transmission chain that performs rate matching puncturing or data matching repetition to match the length of the channel interleaver.

Accordingly, an object of the present invention has been devised in view of the above-mentioned problems of the prior art, and the length of the spreading factor or channel interleaver specified during negotiation not only in the normal data rate mode but also in the variable data rate mode and the multivariate data rate mode is determined. It is an object of the present invention to provide a data rate matching method in a next generation mobile communication system capable of making the effective code rate as low as possible under a prescribed channel environment.

Another object of the present invention is to provide a data rate matching method in a next generation mobile communication system capable of providing maximum performance in matching the size of the predetermined channel interleaver with the length of the output string of the channel encoder.

According to an aspect of the present invention for achieving the above object, in the process of interleaving an information bit string having a predetermined data rate to be mapped to a physical layer, each other according to the relationship between the length of the information bit string and the interleaving size Channel coding at a different code rate, generating the channel coded bit stream in code symbol units, and performing uniform puncturing in any number of code symbol units continuously output among the code symbol units, or And symbolly repeating the channel coded bit stream to match the length of the channel coded bit stream to the interleaving size.

Preferably, in the step of outputting the unit code symbol, the code symbol unit is formed by the inverse bits of the code rate, and in the matching, the uniform puncturing is continuous for the remaining bit strings except for a specific bit string. Simultaneous puncturing is performed in any number of code symbol units output.

In addition, the position of the punctured bits of each symbol unit among the arbitrary number of code symbol units is characterized in that it is made uniformly in the remaining bits except a specific bit.

When the N is greater than 2I and less than or equal to 3I with respect to the interleaving size N and the length I of the information bit string, the inverse k _n of the code rate is 3, and the N is greater than 3I and less than 4I. the k _n is 4, the N is the in the case greater than or equal to less than 5I than 4I k _n is gatneunde to Figure 5, if the k _n is 3 or 5 which is punctured at code symbol unit of the random number The number of bits is 2, and when k _n is 4, the number of bits punctured in the arbitrary number of code symbol units is either 2, 3, or 4.

In the case where k _n is 3 or 5, the arbitrary number of code symbol unit is 2, and when k _n is 4, the arbitrary number of code symbol unit is either 2 or 3. It is done.

Preferably, when the interleaving size is larger than five times the information bit string, a value obtained by dividing a k-th symbol of the channel coded bit string by "(length of k × channel coded bit string) of the information bit string by the interleaving size is obtained. The symbol repetition is performed by estimating from the maximum integer " th symbol not exceeding.

In addition, performing uniform puncturing different from the remaining code symbol units on the code symbol units including the tail bits in the information bit string, and performing the puncturing on the arbitrary number of code symbol units, the remaining code symbol units The other uniform puncturing may be performed or specific uniform puncturing may be performed.

1 illustrates a radio architecture (RC) in a forward link to support variable data rates and multivariate data rates according to the prior art;

2 illustrates a transmission chain of a variable data rate or a variable data rate according to a turbo code according to the present invention.

3 is a view illustrating an example of a puncturing process according to a transmission chain of a variable data rate or a variable data rate according to a turbo code according to the present invention.

4 is a view showing another example of a puncturing process according to a transmission chain of a variable data rate or a variable data rate according to a turbo code according to the present invention;

If the length of the information bit stream input to the channel encoder defined in each radio structure is I, and the size of the channel interleaver defined is N, the normal data rate mode is 1: 1 between I and N. The chain of is formed.

However, it can be considered that the above 1: 1 chain condition is not satisfied in the variable data rate or the multivariate data rate mode. Therefore, a new chain must be made to connect between the length N of the channel interleaver in the current RC and the length I of the information bit string input to the channel encoder.

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

First embodiment

The first embodiment proposes an example of a transmission chain for a variable data rate or a variable data rate for a turbo code.

2 is a diagram illustrating a transmission chain of a variable data rate or a variable data rate according to a turbo code according to the present invention.

Referring to FIG. 2, the input information bit string of the channel encoder has a bit string generated by the following process. That is, in the CRC bit block, a CRC bit having an arbitrary length is added to the channel bit in order to detect an error (S20). In this case, the method of determining the length of the CRC in the new RC is signaled in the initial negotiation stage between the transmitter and the receiver. Can be.

After the CRC bit is added to the channel bit, a tail bit or reserved bits are added to the bit string. (S21) In the case of the turbo code, 6 tail bits and 2 spares are reserved. ) Bits are added.

Subsequently, when a chain other than the normal data rate chain is to be formed in the radio structure using the turbo code, channel coding is performed using a 1 / k _n rate turbo coder as a channel coder (S22).

The output L of the channel encoder uses rate matching puncturing (5I> N) or rate matching repetition (5I <N) for matching between (k _n × I) and the channel interleaver size N (S23).

In this case, k _n is an inverse value of the turbo code rate, and is set to one of {2,3,4,5}. The method for determining the turbo code rate includes the length I and the length of the information input bit string of the channel encoder. It depends on the ratio between the size N of the channel interleaver.

Rate matching repetition for the turbo code is a case where the interleaver size is larger than 5I, and basically an algorithm for satisfying uniformity of energy distribution should be proposed. Therefore, when using rate matching repetition for a turbo code, it is preferable to use the uniform symbol repetition method mentioned in the prior art.

That is, the k th output bit of the output bit string after performing the rate matching iteration is for an index k that increases from 0 to N-1. It can be estimated from the bits of the first information bit string.

For reference, the reason for determining rate matching puncturing or rate matching repetition according to the relationship between 5I and N in FIG. 2 is that the minimum rate of turbo codes that can be used regardless of the ratio of N and I is set to 1/5. Because.

However, the rate matching puncturing for the turbo code has to be made under the following basic assumptions, so that the code of the channel encoder according to the ratio of N and I for better coding gain even under the assumption that 5I is less than N. The rate is determined and the application of the puncturing pattern is also different.

The basic assumptions are summarized in three ways.

(1) Puncture on cystematic bits is excluded.

(2) An equal amount of puncturing is performed on the parity output strings from the two constituent encoders.

(3) The puncturing pattern of the parity output string from each component encoder is designed to have a uniform characteristic.

In addition, one more fundamental problem under the above assumption is that it is desirable in terms of implementation that the puncturing pattern by the newly proposed puncturing algorithm be compatible with the puncturing pattern used at the existing normal data rate. Is the point.

Therefore, we propose a new transmission chain in which puncturing that is compatible with the puncturing pattern defined at the existing normal data rate and satisfying the above three conditions is performed by the puncturing pattern described below. .

First, as described above, the code rate of the turbo encoder must be determined according to the relationship between N and I. Of course, in the case of using the turbo code, all code rates can be thought of as codes generated by puncturing from the 1/5 rate turbo code, so after fixing the code rate of the turbo encoder to 1/5 rate basically, It is also possible to use a method of finally adjusting the code rate in the rate matching puncturing stage. However, since the puncturing block already exists in the existing turbo encoder, it may be used to perform rate matching puncturing on the code rate in the turbo encoder according to the relationship between N and I.

In the present invention, first, the puncturing block inside the turbo encoder is first determined according to the relationship between N and I to determine the output code rate of the turbo coder, and then the length of the output string of the channel coder having the determined code rate and the interleaver A method of matching length is proposed.

If the desired interleaver size is smaller than 5I, puncturing is performed under the conditions shown in Table 1 below.

Pattern range 2I <N≤3Ik _n = 3 3I <N <4Ik _n = 4 4I≤N <5Ik _n = 5 P ₀ P ₁ P ₀ P ₁ P ₀ P ₁ Puncturing pattern 110 101 1101 1101 11101 11011 Tail puncturing pattern 101 101 1011 1011 11011 11011

When the information bit string (having length I) consisting of channel bits, CRC error bits, and tail bits in Table 1 is input to the channel encoder, a chain other than a chain of normal data rates determined on each RC is required. The / k _n rate turbo encoder is used as the channel encoder. Where k _n is the inverse of the code rate of the turbo encoder.

In addition, when the relationship between the length I and N of the information bit string of the turbo encoder is divided into three types, each puncturing pattern is different.

First, k _n has a value of 3 when the interleaver size N is greater than 2I and less than or equal to 3I. Or k _n has a value of 4 when the interleaver size N is larger than 3I and smaller than 4I. Or k _n has a value of 5 when the interleaver size N is greater than or equal to 4I and less than 5I.

Therefore, one information bit outputted from the output bit stream channel-coded and outputted by the 1 / k _n rate turbo encoder and one (k _n -1) parity bits sequentially outputted to the information bit. The unit symbol groups of are formed, and each unit symbol group of I is formed in total.

For example, when k _n has a value of 3, the unit symbol group includes one information bit and two parity bits added from a first constituent encoder and a second constituent encoder configured in the turbo encoder. Form a unit symbol group consisting of. That is, it is formed of a unit symbol group consisting of k _n bits.

Accordingly, the unit symbol groups are given indices that increase from 0 to I-1, and are divided into even and odd groups according to even or odd values of the indexes. Hereinafter, the even group or odd group is collectively referred to as a composite code block.

Each of the composite code blocks is " = J "unit symbol groups, and also contains unit code symbols with the 2j th index in the even group and the 2j + 1 th index in the odd group for the index j increasing from 0 to J-1. .

In the case where the length L of the output bit string of the channel encoder is odd, the puncturing is performed on the I-th unit symbol code group by a tail puncturing pattern as shown in Table 1 above.

remind " Represents the maximum integer not exceeding I divided by two.

Since the length L of the output bit string L of the 1 / k _n rate turbo encoder has a value of "k _n xI", the number of bits K to be punctured in each of the even and odd groups is " Is calculated by ".

In the present invention, as described above, puncturing is uniformly performed on the output bit strings of all channel encoders, and puncturing is performed on the first bit in each unit symbol group corresponding to the input information bits of the channel encoder. In order to avoid the loss, the puncturing pattern used at the normal data rate is used as shown in Table 1 above. However, when the interleaver size N is larger than 3I and smaller than 4I, a modified puncturing pattern of a normal data rate is used.

In particular, in order to achieve uniform puncturing of the output bit stream of the channel encoder, a unit symbol group in which puncturing is activated in each of the even and odd groups may be assigned to a unit symbol group having an index j satisfying Equation 2 below. Allow puncturing to take place.

(j × K) mod J <K

Equation 2 estimates j such that the number of bits K to be punctured in each complex code block (even and odd groups of the first embodiment) is punctured uniformly in J unit code symbol groups. do. In addition, Equation 2 estimates j according to the same principle for the u composite code blocks for a particular k _n in the second embodiment to be described later.

The puncturing process according to the first embodiment will be described in detail with reference to the examples of FIGS. 3 and 4 below.

3 is a diagram illustrating an example of a puncturing process according to a transmission chain of a variable data rate or a variable data rate according to a turbo code according to the present invention.

4 is a diagram illustrating another example of a puncturing process according to a transmission chain of a variable data rate or a variable data rate according to a turbo code according to the present invention.

3 to 4, the puncturing activation unit symbol group satisfying Equation 2 is a unit symbol having an index of 2j th and 2j + 1 th in even and odd groups, respectively, as shown in FIG. 3. When defining a group as a pair relationship, puncturing is simultaneously performed on the unit symbol groups having the pair relationship. The hatched portion in FIG. 3 indicates that puncturing is activated in a unit symbol group having an index of 2j or 2j + 1 for j satisfying Equation 2 above.

However, the unit symbol groups in the pair relationship may be uniformly punctured by differently puncturing bits.

In particular, when the length of the output bit string output from the channel encoder is odd, as shown in FIG. 4, the even group further includes one unit symbol group rather than the odd group, and puncturing must be performed for the unit symbol group. Is activated.

In the first embodiment of the present invention, the inverse k _n of the rates of the turbo encoder is first determined according to the relationship between the interleaver size N and the length I of the information bit string of the channel encoder.

Next we define the puncturing pattern that we will use by default. This puncturing pattern is a pattern based on the puncturing pattern used at the existing normal data rate. By enabling or disabling the puncturing on a per unit symbol group basis based on this pattern, it can be basically compatible with the puncturing pattern of the existing normal data rate. In this case, the 2j and 2j + 1th symbol group pairs, which perform puncturing by different puncturing patterns in each of the even and odd groups, have the meaning of each small puncturing pattern unit constituting the entire puncturing pattern. .

In addition, the puncturing-enabled unit symbol group pair satisfies an equal puncturing condition for parity bits of each component coder constituting the channel coder.

Second embodiment

The second embodiment proposes another example of a transmission chain for a variable data rate or a variable data rate for a turbo code.

Pattern range 2I <N≤3Ik _n = 3, p = 2, u = 2 3I <N <4Ik _n = 4, p = 4, u = 3 4I≤N <5Ik _n = 5, p = 2, u = 2 P ₀ P ₁ P ₀ P ₁ P ₂ P ₀ P ₁ Puncturing pattern 110 101 1101 1101 1010 11101 11011 Tail puncturing pattern 101 101 1011 1011 1010 11011 11011

When the information bit string (having length I) consisting of channel bits, CRC error bits, and tail bits in Table 2 is input to the channel encoder, a chain other than the chain of the normal data rate determined on each RC is required. The / k _n rate turbo encoder is used as the channel encoder. Where k _n is the inverse of the code rate of the turbo encoder.

In addition, when the relationship between the length I and N of the information bit string of the turbo encoder is divided into three types, each puncturing pattern is different.

First, k _n has a value of 3 when the interleaver size N is greater than 2I and less than or equal to 3I. Or k _n has a value of 4 when the interleaver size N is greater than 3I and less than or equal to 4I. Or k _n has a value of 5 when the interleaver size N is larger than 4I and smaller than 5I.

In addition, for unit symbol groups (having indices from 0 to I-1) composed of one information bit and (k _n -1) parity bits sequentially output from the output bit string of the channel encoder. When k _n is 3 or 5, the unit symbol group having an even index is divided into an even group, and the unit symbol group having an odd index is divided into an odd group. In addition, when k _n is 3 or 5, the variable u representing the number of other composite symbol groups formed from the unit symbol groups has a value of 2.

However, when k _n is 4, u has a value of 3. That is, the output bit string output from the 1 / 4-rate channel encoder has a remainder obtained by dividing the index by 3 for unit symbol groups composed of one information bit and three parity bits, and the remainder is 0, 1, or 2. Each unit code symbol having a value is formed of three complex symbol groups.

The unit symbol groups are formed in total I for a particular k _n , and the u complex symbol groups formed again from the unit code symbols are selected from unit code symbols formed from a particular k _n . = J "unit code symbols. The u compound symbol groups formed for the particular k _n are from uj to" u (j + 1) -1 "for an index j that increases from 0 to J-1. Contains unit code symbols with an index of.

remind " "Represents a maximum integer not exceeding I divided by u.

As in the first embodiment, when the length L of the output bit string of the channel encoder is odd, the I-1 th unit code group among the u complex symbol groups formed for a specific k _n is tailed as shown in Table 2 below. The puncturing is performed by the puncturing pattern.

The unit code symbol groups having a value of "u (j + 1) -1" at the index uj in the u complex symbol groups formed from the specific k _n may be applied simultaneously if this j satisfies Equation 1 above. It has a pair relationship in which puncturing is performed.

However, the unit code symbols in the pair relationship are performed in different puncturing patterns for the same k _n as shown in Table 2 above. In addition, when k _n is 4, unlike in the first embodiment, a complex symbol group is formed into three groups, and the number of bits p punctured in the activated unit code symbols of an activated pair relationship is 4 Has a value. This is to allow the puncturing of a small unit punctured by the pair relationship to support the puncturing pattern of the normal data rate. When k _n is 3 or 5, the number of bits p punctured in the activated unit code symbols of the pair relationship has a value of 2.

Therefore, the number of bits K punctured in the composite symbol groups formed for the particular k _n is " It can be calculated by ".

As in the first embodiment, the puncturing for the first bit is not performed as shown in Table 2 in order to exclude the puncturing for the information bit as described above. In addition, puncturing is performed on j satisfying Equation 2 to perform uniform puncturing of the entire output bit string.

In conclusion, the difference between the puncturing algorithm using Table 2 and the puncturing algorithm using Table 1 is that the latter puncturing algorithm divides the unit code symbols into an even group and an odd group, whereas the former puncturing algorithm It is divided by the number of unit puncturing patterns constituting one overall puncturing pattern. For example, if the interleaver size N is greater than 3I and less than or equal to 4I, the entire output bit string of the channel encoder is one information bit and three parity bits sequentially outputted to this information bit into one unit code group. The unit code group is divided into three compound symbol groups, and the puncturing pattern shown in Table 2 is applied to this compound symbol unit.

Third embodiment

The third embodiment proposes another example of a transmission chain for a variable data rate or a variable data rate for a turbo code.

Pattern range 2I <N≤3Ik _n = 3, p = 2, u = 2 3I <N <4Ik _n = 4, p = 3, u = 3 4I≤N <5Ik _n = 5, p = 2, u = 2 P ₀ P ₁ P ₀ P ₁ P ₂ P ₀ P ₁ Puncturing pattern 110 101 1101 1110 1011 11101 11011 Tail puncturing pattern 101 101 1011 1011 1011 11011 11011

When the information bit string (having length I) consisting of channel bits, CRC error bits, and tail bits in Table 2 is input to the channel encoder, a chain other than the chain of the normal data rate determined on each RC is required. The / k _n rate turbo encoder is used as the channel encoder. Where k _n is the inverse of the code rate of the turbo encoder.

When the relationship between the length I and N of the information bit string of the turbo encoder is divided into three types, each puncturing pattern is different.

First, k _n has a value of 3 when the interleaver size N is greater than 2I and less than or equal to 3I. Or k _n has a value of 4 when the interleaver size N is greater than 3I and less than or equal to 4I. Or k _n has a value of 5 when the interleaver size N is larger than 4I and smaller than 5I.

In addition, for unit symbol groups (having indices from 0 to I-1) composed of one information bit and (k _n -1) parity bits sequentially output from the output bit string of the channel encoder. When k _n is 3 or 5, the unit symbol group having an even index is divided into an even group, and the unit symbol group having an odd index is divided into an odd group. In addition, when k _n is 3 or 5, the variable u representing the number of other composite symbol groups formed from the unit symbol groups has a value of 2.

However, when k _n is 4, u has a value of 3. That is, the output bit string output from the 1 / 4-rate channel encoder has a remainder obtained by dividing the index by 3 for unit symbol groups composed of one information bit and three parity bits, and the remainder is 0, 1, or 2. Each unit code symbol having a value is formed of three complex symbol groups.

The unit symbol groups are formed totally I for a particular k _n , and the u complex symbol groups formed again from the unit code symbols are selected from unit code symbols formed from a particular k _n . = J "unit code symbols. The u compound symbol groups formed for the particular k _n are from uj to" u (j + 1) -1 "for an index j that increases from 0 to J-1. Contains unit code symbols with an index of.

remind " "Represents a maximum integer not exceeding I divided by u.

The difference from the second embodiment is that the tail puncturing pattern shown in Table 3 is applied to the last (L mod u) unit symbol groups according to the relationship between the length L and u of the output bit string of the channel encoder. Is to do the processing.

Fourth embodiment

The fourth embodiment proposes another example of a transmission chain for a variable data rate or a multivariate data rate for a turbo code.

Pattern range 2I <N≤3Ik _n = 3, p = 2, u = 2 3I <N <4Ik _n = 4, p = 3, u = 3 4I≤N <5Ik _n = 5, p = 2, u = 2 P ₀ P ₁ P ₀ P ₁ P ₂ P ₀ P ₁ Puncturing pattern 110 101 1101 1111 1010 11101 11011 Tail puncturing pattern 101 101 1011 1111 1010 11011 11011

The difference between the third embodiment and the fourth embodiment is the puncturing pattern when the interleaver size N is larger than 3I and smaller than 4I. When puncturing is performed through the puncturing pattern, the rest of the algorithm may use the same algorithm as in the third embodiment. However, if L is not a multiple of 3, you will need to do some additional puncturing using a slightly different method. That is, if L is not a multiple of 3, additional puncturing must be performed on the last (L mod u) code symbol group. In this case, the puncturing pattern used is P ₀ regardless of the index of the code symbol group. Should be.

Of course, the proposed scheme of activating the puncturing pattern in the unit code symbol unit can be applied to the case where the turbo encoder is always fixed to 1/5. At this time, in defining the puncturing pattern, it should be defined to include the puncturing pattern defined in the existing turbo encoder.

As described above, the present invention has an implementation advantage since the puncturing pattern is compatible with the puncturing pattern used at the existing normal data rate.

In addition, in the current 3GPP2 system, when the variable data rate, the variable data rate mode for the auxiliary channel, or both are supported, in addition to the time diversity gain due to symbol repetition, the coding gain due to the actual code rate reduction can be obtained. As a result, the required transmission power can be lowered.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the examples, but should be defined by the claims.

Claims (10)

In the process of interleaving such that an information bit string having a predetermined data rate is mapped to a physical layer, Channel encoding at different code rates according to a relationship between the length of the information bit string and the interleaving size; The channel coded bit string is generated in code symbol units, and uniform puncturing is performed in any number of code symbol units continuously output among the code symbol units, or the symbol code is repeated by repeating the channel coded bit strings. And matching the length of the channel coded bit string to the interleaving size. The method of claim 1, wherein in the step of outputting the unit code symbol And the code symbol unit is formed by an inverse bit of the code rate. The method of claim 1 wherein in the step of matching The uniform puncturing is a rate matching method in a next generation mobile communication system, characterized in that simultaneous puncturing is performed in units of any number of code symbols that are continuously output for the remaining bit strings except for a specific bit string. 4. The rate matching method of claim 3, wherein the puncturing bit position of each symbol unit among the arbitrary number of code symbol units is uniform in the remaining bits except for a specific bit. The inverse (k _n ) of the code rate is 3 when N is greater than 2I and less than or equal to 3I with respect to the interleaving size N and the length I of the information bit string. the larger the k is smaller than _n 4I is a 4, wherein the N is in the case greater than or equal to less than 5I than 4I _n k is the rate matching method in the next generation mobile communication system, comprising the five. 6. The method of claim 5, wherein when k _n is 3 or 5, the number of bits punctured in the unit of any number of code symbols is 2, and when k _n is 4, the number of bits is punctured in the unit of any number of code symbols. The number of bits to be processed is any one of two, three or four rate matching method in the next generation mobile communication system. 6. The method of claim 5, wherein the number of code symbol unit units is 2 when k _n is 3 or 5, and the number of code symbol unit units is 2 or 3 when k _n is 4. Rate matching method in the next generation mobile communication system, characterized in that one. 2. The method of claim 1, wherein when the interleaving size is larger than five times the information bit string, the kth symbol of the channel coded bit string is set to "(k x channel coded bit string length) of the information bit string as the interleaving size. And performing symbol repetition by estimating from the " maximum integer &quot; symbol that does not exceed a divided value. 2. The method of claim 1, wherein uniform puncturing different from the remaining code symbol units is performed on code symbol units including tail bits in the information bit string. 10. The next generation mobile communication of claim 9, wherein after performing the puncturing on the arbitrary number of code symbol units, the other uniform puncturing or the specific uniform puncturing is performed on the remaining code symbol units. Rate matching method in system.