KR102274237B1 - Compression and decomporession method and mobile communication repeater using the same - Google Patents

Abstract

Disclosed are a data compression and decompression method and a mobile communication repeater to which they are applied. In the data compression method according to an embodiment of the present invention, a predetermined number of consecutive bits (sign bits) of the beginning of the first bit string are allocated to the first region of the second bit string, and in the bit string after the sign bit of the first bit string, The number of bits in which the sine bit is repeated is counted, and the counted number is allocated to the second region of the second bit string as a binary number having a length corresponding to the size of the compressed bit.

Description

Data compression and decompression methods and mobile communication repeaters to which they are applied {COMPRESSION AND DECOMPORESSION METHOD AND MOBILE COMMUNICATION REPEATER USING THE SAME}

The present invention relates to a data compression and decompression method and a mobile communication repeater to which they are applied.

In general, in a mobile communication system, a mobile communication signal is transmitted from a base station to a terminal or from a terminal to a base station. However, depending on the region, there are shaded areas where the signal does not reach, and a repeater is installed and operated to solve these shaded areas.

These repeaters are variously classified into optical repeaters, frequency conversion repeaters, frequency non-conversion repeaters, microwave (M/W) repeaters, laser repeaters, etc. could be

The dual digital repeater is composed of a main hub unit (MHU) that transmits and receives signals with a base station, and a remote optic unit (ROU) that transmits and receives signals with a user terminal and is installed in a shaded area. At this time, these units convert the analog signal received from the base station or the user terminal into a digital signal, and then transmit the converted digital signal to the other unit through a transmission path (eg, optical fiber, etc.).

Meanwhile, with the development of mobile communication technology, the use of radio resources having a higher frequency band and a wider frequency bandwidth is required. However, there is bound to be a limit to the data rate that the transmission path of the digital repeater can transmit. In order to overcome this limitation, data compression technology is applied in the digital conversion process of the digital repeater.

Conventionally, as a compression technique applied to a digital repeater, a down-sampling method for reducing sampling of a digital I/Q (in-phase, quadrature-phase) signal, and down-quantization for reducing a quantization level of sampled data (down-quantizing) method, etc.

Among them, in the down quantization method, a partial bit method in which a least significant bit (LSB) portion is cut and transmitted according to a target number of bits in a bit stream quantized as digital data, and quantized There is a method of encoding at non-linear intervals according to the distribution of samples in a bit string, and a block-scaling method in which I/Q samples for a certain time are designated as blocks and quantized according to the target number of bits in blocks. .

However, since this conventional down-quantization method loses a lot of data in the process of data compression and decompression, performance degradation such as an increase in error vector magnitude (EVM) and an increase in delay time occurs, making it difficult to apply to a digital repeater. There is a problem. In addition, since this down-quantization method is applicable to a case where a fixed quantization level is satisfied, there is a problem in that performance required for a digital repeater cannot be guaranteed.

The technical problem to be solved by the present invention is to provide a data compression and decompression method having a high compression rate, low loss, and short delay time, and a mobile communication repeater to which they are applied.

Another technical problem to be solved by the present invention is to provide a data compression and decompression method that can be set to have an optimal compression efficiency by changing a compression parameter according to the level of an input signal, and a mobile communication repeater to which they are applied.

In order to solve the above technical problem, the method of an embodiment of the present invention for generating compressed data of a second bit string by compressing a first bit string obtained by converting an input signal into digital data, allocating a predetermined number of consecutive bits (sine bits) to a first region of the second bit string; counting the number of bits in which the sign bit is repeated in the bit string after the sign bit of the first bit string; and allocating the counted number to the second region of the second bit string as a binary number having a length corresponding to the size of the compressed bit.

The method according to an embodiment of the present invention comprises the steps of allocating the sign bit of the first bit string and the bits after the bit corresponding to the counted number to the third region of the second bit string according to the size of the remaining bits. may include more.

The method according to an embodiment of the present invention may further include determining the size of the compression bit according to the input signal.

In an embodiment of the present invention, the determining of the size of the compressed bit includes setting a value of a first size when the input signal is greater than or equal to a predetermined level, and greater than the first size when the input signal is equal to or less than the predetermined level. It can be set to a value of the large second size.

In an embodiment of the present invention, the determining of the size of the compression bit includes setting a value of a first size when the input signal is downlink, and is larger than the first size when the input signal is uplink. It can be set to a value of the second size.

In an embodiment of the present invention, in the step of allocating to the second region, when the size of the compressed bit is the maximum value of the count of the second region, the second region having a length corresponding to the size of the compressed bit A binary number corresponding to the maximum value of the count of may be allocated to the second region.

In one embodiment of the present invention, in the step of allocating to the third region, when the size of the compressed bit is smaller than the maximum value of the count of the second region, the sign bit and the counted bit in the first bit string Bits after the bit corresponding to the number may be allocated to the third region.

The method according to an embodiment of the present invention may further include generating a frame including the compressed data of the second bit string.

In an embodiment of the present invention, the frame may include information on the size of the compression bit.

In addition, in order to solve the above technical problem, the method of an embodiment of the present invention for generating digital data of a second bit string by decompressing the compressed data of the first bit string, in the first bit string, dividing a first region corresponding to the number of consecutive bits (sine bits), a second region corresponding to compressed bits, and a third region corresponding to residual bits; repeating the sine bit by a number (m) corresponding to the binary number of the second region and assigning it to a fourth region of the second bit string; and allocating the sine bit of the first region to a fifth region of the second bit string.

The method according to an embodiment of the present invention may further include allocating the remaining bits of the third region to a sixth region of the second bit string.

The method according to an embodiment of the present invention may further include determining the size of a compression bit from a predetermined flag of a frame including the first bit string.

In the method of an embodiment of the present invention, when m is less than the maximum value of the count of the second region, a bit different from the sine bit corresponding to the corresponding bit is allocated to the next bit of the bit corresponding to m It may further include the step of

In addition, in order to solve the above technical problem, the mobile communication repeater of an embodiment of the present invention for relaying a signal between a base station and a user terminal converts an input signal received from the base station or the user terminal into digital data to produce a first conversion unit for generating a 1-bit string; and a compression unit generating compressed data of a second bit string by compressing the first bit string, wherein the compression unit converts a predetermined number of consecutive bits (sign bits) of the first bit string to the second bit string of the second bit string. Allocated to area 1, in the bit string after the sign bit of the first bit string, the number of bits in which the sign bit is repeated is counted, and the counted number is converted into a binary number having a length corresponding to the size of the compressed bit. It can be allocated to the second area of the 2-bit string.

In addition, in order to solve the above technical problem, the mobile communication repeater of an embodiment of the present invention relaying a signal between a base station and a user terminal extracts compressed data of a first bit string from a frame received through a transmission line. processing unit; and a decompression unit for decompressing the compressed data into data data of a second bit string, wherein the decompression unit includes a first corresponding to a first predetermined number of consecutive bits (sine bits) in the first bit string. A region and a second region corresponding to the compressed bit are divided, the sine bit is repeated as many times as the number corresponding to the binary number of the second region is allocated to the third region of the second bit string, and the sign of the first region is A bit may be allocated to a fourth region of the second bit string.

The present invention as described above has an effect of providing a compression technique having a high compression ratio, low loss, and short delay time.

In addition, the present invention has the effect of having an optimal compression efficiency by changing the compression parameter according to the level of the input signal.

1 shows a schematic diagram of a mobile communication repeater according to an embodiment of the present invention.
2 is an exemplary diagram for explaining a signal transmission process of a first unit of a mobile communication repeater according to an embodiment of the present invention.
3 is an exemplary diagram of a first bit string generated by the first AD converter.
4 is an exemplary diagram for explaining the probability normal distribution of the input signal, the first bit string (BS ₁ ), and the compressed data (CB).
5 is a flowchart for explaining the compression step of FIG. 2 in detail.
6 shows an example (downlink) of a frame structure and setting a value of c that is adjusted according to an input signal level.
7 is an exemplary diagram for explaining a signal reception process of a second unit of a mobile communication repeater according to an embodiment of the present invention.
8 is a flowchart for explaining the decompression step of FIG. 7 in detail.
9 is a schematic diagram for explaining an example of compressing and decompressing an I/Q signal in a mobile communication repeater according to an embodiment of the present invention.
10 is an exemplary diagram showing the SQNR performance according to the input signal level of the digital repeater according to an embodiment of the present invention.

In order to fully understand the configuration and effect of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various forms and various modifications may be made. However, the description of the present embodiment is provided so that the disclosure of the present invention is complete, and to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention. In the accompanying drawings, components are enlarged in size than actual for convenience of description, and ratios of each component may be exaggerated or reduced.

Terms such as 'first' and 'second' may be used to describe various elements, but the elements should not be limited by the above terms. The above term may be used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a 'first component' may be referred to as a 'second component', and similarly, a 'second component' may also be referred to as a 'first component'. can Also, the singular expression includes the plural expression unless the context clearly dictates otherwise. Unless otherwise defined, terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those of ordinary skill in the art.

Hereinafter, a mobile communication repeater according to an embodiment of the present invention and a data compression and decompression method thereof will be described in detail with reference to FIGS. 1 to 10 .

1 is a configuration diagram schematically illustrating a mobile communication repeater according to an embodiment of the present invention.

As shown in the figure, the mobile communication repeater 1 of an embodiment of the present invention is a system for relaying signals between a base station 2 and a user terminal 3, and a first unit 10 and a second It may be configured to include the unit 20 .

The first unit 10 is a unit for transmitting and receiving signals to and from the base station 2 , and may be a master hub unit (MHU). In addition, the second unit 20 is a unit for transmitting and receiving a signal to and from the user terminal 3, it may be a remote optical unit (ROU). At this time, an analog signal is used for the interface connected to the base station 2 or the user terminal 3, and the mobile communication repeater 1 of the present invention digitizes the analog signal to the unit distributed through the transmission line 30. It may be configured to transmit a signal. For signal transmission through the transmission line 30 of the first unit 10 and the second unit 20, various optical devices such as a small form-factor pluggable (SFP) terminal may be employed, but are omitted for convenience of description. I will do it.

The first unit 10 digitally samples an input signal that is an analog signal received from the base station 2 to generate digital data, compresses the generated digital data according to an embodiment of the present invention, and then converts the compressed data to an optical fiber. It can be transmitted to the second unit 20 using a transmission line 30 such as.

The second unit 20 decompresses the compressed data received from the first unit 10 into original digital data, converts the decompressed digital data into an analog signal, and transmits it to the user terminal 3 .

Similarly, the second unit 20 generates digital data by digitally sampling an input signal that is an analog signal received from the user terminal 3, compresses the generated digital data according to an embodiment of the present invention, and then compresses Data may be transmitted to the first unit 10 using the transmission line 30 .

The first unit 10 decompresses the compressed data received from the second unit 20 into original digital data, converts the decompressed digital data into an analog signal, and transmits it to the base station 2 .

Specifically, the first unit 10 and the second unit 20, as shown in FIG. 1, the frequency converters 11 and 21, the baseband processing units 12, 22, AD (Analog to Digital) Transformers 13 and 23, DA (Digital to Analog) converters 14 and 24, compression units 15 and 25, decompression units 16 and 26, frame processing units 17 and 27, and transmission units ( 18, 28) may be included, respectively. Hereinafter, for convenience of explanation, 'first' is added in front of the name of each detailed configuration included in the first unit 10, and 'second' is added before the name of each detailed configuration included in the second unit 20. ' will be added.

The description of the detailed configuration of the first unit 10 and the second unit 20 will be mainly described with reference to the following signal transmission process.

2 is an exemplary diagram for explaining a signal transmission process of a mobile communication repeater according to an embodiment of the present invention.

First, from the base station 2 to the first unit 10 of the mobile communication repeater 1, from the first unit 10 to the second unit 20, and from the second unit 20 to the user terminal 3 , a downlink process in which each signal is transmitted will be described first.

The first frequency converter 11 may convert an input signal of a radio frequency (RF) band received from the base station 2 into a signal of an intermediate frequency (IF) band (S10).

The first baseband processing unit 12 may convert the signal of the IF band converted by the first frequency converter 11 into a signal of the baseband band (S20). In this case, the converted baseband signal may include an I (in-phase) signal and a Q signal (quadrature-phase).

The first AD converter 13 may convert the baseband signal converted by the first baseband processor 12 into digital data through digital sampling (S30). In this case, the generated bit string of digital data will be referred to as a ' _{first bit string (BS 1 )'.}

3 is an exemplary diagram of a first bit string generated by the first AD converter.

As shown in Figure 3, the first bit string (BS ₁ ), the I signal is digitally sampled I bits (I ₀ , I ₁ , I ₂ , ...), and the Q signal is digitally sampled Q bits (Q ₀ , Q ₁ , Q ₂ , …), in which I bits (I ₀ , I ₁ , I ₂ , …) and Q bits (Q ₀ , Q ₁ , Q ₂ , …) are sequentially cross-mixed could be heat. That is, the first bit string BS ₁ is 'I ₀ , Q ₀ , I ₁ , Q ₁ , I ₂ , Q ₂ , ... ' or 'Q ₀ , I ₀ , Q ₁ , I ₁ , Q ₂ , I ₂ , ... ' can be However, hereinafter, for convenience of description, it is assumed that _{the first bit string BS 1} is 'I ₀ , Q ₀ , I ₁ , Q ₁ , I ₂ , Q _{2 , ...'.}

Since a typical digital repeater utilizes a signal output as a 14-bit bit string, FIG. 3 shows that the first bit string BS ₁ is 28 bits by adding the 14-bit I/Q signals, respectively, but the present invention The present invention is not limited thereto.

In addition, digital data may have various formats such as 1's complement, 2's complement, binary offset, etc. However, since a general communication system utilizes an output format of 2's complement, digital data is 2's complement in the present invention. Although it will be described assuming that the output is output as , the present invention is not limited thereto, and may be configured in various formats.

Referring back to FIG. 2 , the first compression unit 15 may compress the first bit string BS ₁ generated by the first AD conversion unit 13 ( S40 ). In this case, the compressed data will be referred to as 'compressed data (CB)'.

4 is an exemplary diagram for explaining the probability normal distribution of the input signal, the first bit string (BS ₁ ), and the compressed data (CB).

If by reference to Figure 4, the first bit stream (BS ₁₎ it may be composed of a sign bit (SignBit) and the sign bit after the bit string, excluding the sign bit in a second bit stream (BS _2).

The sine bit may be the first predetermined number of consecutive bits in the first bit string BS ₁ , and may be, for example, two consecutive bits. In the example of FIG. 4 , the sine bit may include I ₀ and Q ₀ . When the sine bit is two consecutive bits, the number of corresponding cases is [0, 0], [0, 1], [1, 0], [1, 1], and there may be 4 sets. However, this is an example, and the number of sign bits is not limited thereto.

Also, the second bit string BS ₂ may be a remaining bit string except for the sign bit in the first bit string BS _{1 .}

Further, Fig. When the 4 as a reference, the compressed data (CB) is the sign bit region (R _1), the second bit stream (BS ₂₎ compressed bit region compressed bits are occupied in (R _2), and a second bit It can be seen _{that the residual bit area R 3} occupied by the remaining uncompressed bits in the column BS _{2 is included.}

A sine bit is allocated to the sine bit area R ₁ of the compressed data CB, and a compressed bit from the second bit string BS ₂ is allocated to the compressed bit area R ₂ , and the residual bit area R ₃ ) may be allocated the remaining uncompressed bits of the second bit string BS _{2 .} The size of the residual bit region R ₃ may be determined by determining the size of the compressed bit region R ₂ and the total target compression size.

Under the assumption that the probability of the magnitude of the level of a general input signal has a normal distribution, the first compression unit 15 according to an embodiment of the present invention provides that the input signal level has a root mean square of a predetermined size (eg, -10 dBm) or more ( root mean square, RMS) voltage (high level), the size of the compressed bit ( CompBitSize _{), which is the size of the compressed bit region (R 2} ), is set to the first size, and the input signal level (low level) lower than that In the case of , the second size may be set to be larger than the first size. This is because the probability normal distribution tends to be more concentrated when the input signal is at a low level than when the input signal is at a high level.

In this case, the magnitude of the input signal level may be measured only for a certain window size of the input signal, or may be determined by measuring the overall magnitude of the input signal.

In one embodiment of the present invention, for example, when the input signal level is a high level, the size of the compression bit ( CompBitSize ) is set to 3, and when the input signal level is a low level, the size of the compression bit ( CompBitSize ) is set to 4 can be set to

However, this is an example, and the size of the compression bit ( CompBitSize ) may be variously changed according to the size of the input signal or the link path. For example, in the optical repeater system, the size of the input signal is relatively constant and the size of the compression bit ( CompBitSize ) is set to 3 in the adjustable downlink path, whereas the size of the compression bit ( CompBitSize ) is set to 4 in the uplink path. You can also operate it the way you use it. However, the size is not limitedly used in one embodiment of the present invention, and may be selected in various ways.

Alternatively, the compression bit size ( CompBitSize ) may be adaptively changed and operated according to a signal level within a certain period (a specific window size).

The first compression unit 15 may compress the IQ data reconstructed into _{the first bit string BS 1 .} That is, when the compression bit size (CompBitSize ) is adaptively determined according to the level of the input signal, etc., when the same pattern as the _{sine bit is continuously repeated from the beginning of the second bit string (BS 2} ), the bit in which the sine bit is repeated By counting the number (n) of the compression bit count ( CompBitCount ) parameter can be determined.

Specifically, to determine the compressed bit area (R ₂ ) and the residual bit area (R ₃ ), the first compression unit 15 counts the number of bits (n) in which the sine bit is repeated to the maximum (2 ^c - 1) (however, c is CompBitSize ) can be counted.

In this case, as described above, the size of the compression bit ( CompBitSize ) can be adaptively set according to the input signal level.

If the compression bit count CompBitCount exceeds (2 ^c -1) (where c is the size of the compressed bits ( CompBitSize )), the first compression unit 15 may not count any more.

Thereafter, the first compression unit 15 allocates a binary number corresponding to the compressed bit count ( CompBitCount ) of the length of the compressed bit size ( CompBitSize ) to the _{compressed bit area ( R 2} ), and the remaining bit area ( R ₃ ) Counts sine bits and compressed bits ( CompBitCount ) as much as the number of bits size ( ResidualBitSize ) It is possible to configure a bitstream having a target compressed data (CB) length by allocating the bit data after the number.

This will be described in more detail with reference to the drawings.

5 is a flowchart for explaining the compression step of FIG. 2 in detail.

Specifically, referring to FIG. 5 , the first compression unit 15 determines the size ( CompBitSize ) parameter, which is the number of bits _{in the compressed bit region R 2} , according to the level of the input signal (S40a), and the sine A bit may be allocated to the sine bit region R ₁ (S40b).

Thereafter, the first compression unit 15 may determine the compression bit count ( CompBitCount ) parameter by counting the number of consecutively repeated sine bits from the beginning _{of the second bit string BS 2 .}

That is, in one embodiment of the present invention, if the sine bit is [0, 0] (S40c), the number of repeated '0' consecutively from the beginning of _{the second bit string (BS 2) is counted to count the compressed bit count (} CompBitCount ) can be determined (S40d). For example, the second bit string BS ₂ is '0001... ', counts up to '000', and the compressed bit count ( CompBitCount ) is 3.

In addition, if the sine bit is [0, 1] (S40e), the number of consecutive repetitions of '0' and '1' from the beginning of _{the second bit string BS 2 may be counted (S40f).} For example, the second bit string BS ₂ is '010100... ', counts up to '01010', and the compressed bit count ( CompBitCount ) is 5.

In addition, if the sine bit is [1, 0] (S40g), it is possible to count the number of repeated '1' and '0' continuously from the beginning of _{the second bit string BS 2 (S40h).} For example, the second bit string BS ₂ is '10100... ', counts up to '1010', and the compressed bit count ( CompBitCount ) is 4.

In addition, if the sine bit is [1, 1], it is possible to count the number of consecutive repetitions of '1' from the beginning of _{the second bit string BS 2 (S40i).} For example, the second bit string BS ₂ is '1111110... ', counts up to '111111', and the compressed bit count ( CompBitCount ) is 6.

Then, when the compression bit count ( CompBitCount ^{) is smaller than the maximum value (2 c} -1) of the count of the compressed bit area (c is the size of the compressed bit ( CompBitSize )) (S40j), the size of the compressed bit ( CompBitSize ) of the length A binary number corresponding to the compressed bit count ( CompBitCount ) is allocated to the compressed bit area (R ₂ ) (S40k), and the size of the residual bits in the bits after ( CompBitCount _{+1) in the second bit string (BS 2} ) ( ResidualBitSize ) A number of bits may be allocated to the residual bit region R ₃ (S401).

For example, the size ( CompBitSize ) of the compressed bit allocated to the compressed bit area ( R ₂ ) is 3, the sine bit is [0, 1], and the second bit string (BS ₂ ) is '01010011111010... 'Let's consider the case.

The first compression unit 15 may determine the compression bit count CompBitCount to be 5 until '01010'. At this time, since the compression bit count ( CompBitCount ) is less than 7, which is (2 ³ -1), the binary number '101' corresponding to the compression bit count ( CompBitCount ) of the length of the compression bit size ( CompBitSize ) corresponding to 5 is compressed. Allocated to the bit region (R ₂ ), the remaining bits except for the (5+1)th 6th bit (010100) of the second bit string (BS ₂ ), that is, the size of the remaining bits from the 7th bit ( ResidualBitSize) ) may be allocated to the residual bit area R _{3 .}

At this time, '0', which is the 6th bit of the second bit string BS ₂ , corresponds to a point where the sine bit [0, 1] is not continuously repeated. Therefore, even if information on the 6th bit '0' of the second bit string BS _{2 is not allocated to the residual bit region R 3} , the compressed data CB is already 6 of the second bit string BS ₂ . It contains information about the th bit '0'.

In other words, in data compression the second unit 20 receives the (CB), the compression bit region (R ₂₎ up to the ^(23-1), the value of the binary bit compression region (R _2), that is less than 7 In this case, the next bit of '5', that is, the 6th bit, which is the number represented by the binary number of the _{compressed bit area R 2} in the compressed data CB, is omitted, and [0, 1], where the 6th bit is the sine bit, is repeated. Considering that it corresponds to the first point that does not occur, the 6th bit '0' may be derived.

On the other hand, in S40j, when the compression bit count ( CompBitCount ) is greater than or equal to (2 ^c -1) (c is the size of the compressed bit ( CompBitSize )), the compression bit count ( CompBitCount ) is set to (2 ^c -1) (c is set to the size of the compressed bit (CompBitSize)), and assigning the binary number of the compressed bit count (the size of the compressed bit corresponding to CompBitCount) (CompBitSize) length of a compressed bit region (R ₂₎ and (S40m), the second bit string In (BS ₂ ), the number of bits of the size of residual bits ( ResidualBitSize ) in bits after the compression bit count ( CompBitCount ) may be allocated to the residual bit area (R ₃ ) (S40n).

For example, the size of the compressed bit ( CompBitSize ) of the compressed bit region (R ₂ ) is 4, the sine bit is [0, 0], and the second bit string (BS ₂ ) is '0000000000000001010... ', counts up to '0000000000000000', The size of the compressed bit ( CompBitSize ) is 15. At this time, since the size of the compressed bit ( CompBitSize ) is equal to 15, which is (2 ⁴ -1), the first compression unit 15 converts '1111', which is a 4-bit binary number corresponding to 15, to the compressed bit area (R ₂ ) can be assigned to

In addition, the first compression unit 15 in the second bit stream (BS ₂₎ in a second bit stream (BS ₂₎ with the exception of a bit (000 trillion) to the 15th bit, that is the size of the remaining bits from the 16th bit ( ResidualBitSize ) The number of bits (1010...) may be allocated _{to the residual bit area (R 3 ).}

At this time, '1', which is the 16th bit of the second bit string (BS ₂ ), corresponds to a point where the sine bit [0, 0] is not continuously repeated. In this case, however, the second bit stream (BS ₂₎ 16-th bit information of the "1" state to be assigned to the remaining bit region (R _3), which is continuous to the 16th of a second bit stream (BS ₂₎ of Therefore, even when '0' is repeated, the compressed bit region R ₂ is allocated as '1111', which is a 5-bit binary number.

That is, the compressed data in the second unit 20 receives the (CB), the compressed bit region (R ₂₎ a compressed binary bit region (R _2), the maximum value of ^(24-1), i.e., such as 15 of the In this case, it is determined that the next bit of '15', that is, the 16th bit, which is a number indicated by the binary number of the _{compressed bit region R 2} in the compressed data CB, is not omitted.

Thereafter, the first frame processing unit 17 may generate a frame including the compressed data CB generated by the first compression unit 15 . That is, the first frame processing unit 17 may function as a framer.

In this case, in addition to the compressed data CB, the frame may further include information such as identification information of a transmission destination and information on the size of a compressed bit ( CompBitSize ) (Compbit-Flag). In addition, the frame may further include information on the position and number of the sign bits, and if there is no information on this, the sign bits may be regarded as the first two bits.

FIG. 6 is an exemplary view for explaining a frame structure generated by the frame processing unit of FIG. 1 .

When the drawing to refer to the first frame processing unit may include a flag (CompBit-Flag) and a plurality of compressed data that contains information about the size of the compressed bit (CompBitSize) a frame (17) is generated.

In an example of the present invention, an example in which CompBit-Flag is 1 bit and each compressed data is 18 bits is described, but the present invention is not limited thereto.

For example, in a downlink path in which the size of an input signal is relatively constant and adjustable, CompBit-Flag is 0, and it may be determined that the size of the compression bit (CompBitSize) represents 3. Also, in the uplink path, CompBit-Flag is 1, which may be determined to indicate that the size of the compression bit (CompBitSize) is 4.

Thereafter, the first transmission unit 18 may transmit the frame generated by the first frame processing unit 17 to the second transmission unit 28 of the second unit 20 ( S50 ). At this time, the first transmission unit 18 and the second transmission unit 28 may be connected to a transmission line 30 such as an optical fiber to transmit and receive frames through optical communication.

7 is an exemplary diagram for explaining a signal reception process of a second unit of a mobile communication repeater according to an embodiment of the present invention.

As shown in the drawing, the frame received by the second transmission unit 28 through the transmission line 30 may be decompressed by the second frame processing unit 27 and the decompression unit 26 .

That is, the second frame processing unit 27 extracts the compressed data CB by dividing the received frame, and the second decompression unit 26 decompresses the compressed bit region R _{2 of the compressed data CB.} By decompressing, the compressed data CB may be restored to the original bit string (S60).

At this time, the second frame processing unit 17 functions as a de-framer, and the second decompression unit 26 includes a sine bit area R ₁ and a compressed bit area ( R ₂ ) and the residual bit area R ₃ may be distinguished, and the compressed data of the compressed bit area may be decompressed.

8 is a flowchart for explaining the decompression step of FIG. 7 in detail.

Referring to FIG. 8 , the second decompression unit 26 according to an embodiment of the present invention includes compressed data CB, that is, a sine bit area R ₁ , a compressed bit area R ₂ , and a residual bit area ( After distinguishing the bits of R ₃ ) ( S60a ), a different value may be assigned to the decompression bit region according to the size of the compressed bit region R2 .

In this case, the third bit string BS ₃ , which is a bit string of the restored digital data, may include a sine bit area R ₁ , a decompressed bit area and a residual bit area R ₃ .

A third sign bit area of bit sequences (BS ₃₎ (R ₁₎ and a residual bit region (R ₃₎ are each a bit of the compressed data (CB) sign bit region (R ₁₎ and a residual bit region (R ₃₎ of the is allocated, and the decompressed bit area may be allocated a bit in which the compressed bit occupying the compressed bit _{area R 2 is decompressed.}

Specifically, when the number m corresponding to the binary number of the compressed bit area R2 is smaller than the maximum value (2 ^c _{-1) of the compressed bit area R 2} (c is CompBitSize ) (S60b), the sine bit area Repeat the bit of (R ₁ ) by m and assign it to the decompression bit area (S60c), and to the (m+1)th bit, a bit different from the sine bit corresponding to the corresponding bit can be assigned to the decompression bit area. There is (S60d). This is because the (m+1)th bit corresponds to the first point where the sine bit is not repeated.

For example, when CompBit-Flag=0 of the received frame, the size of the compressed bit ( CompBitSize ) means 3, the sine bit area (R ₁ ) is '10', and the compressed bit area (R ₂ ) is Let us consider the case of '101'. Compressed bit region (R ₂₎ '101' corresponding to number 5 is compressed bit region (R ₂₎ the maximum value of ^(23-1) of the count, that is smaller than 7, the decompression zone of the bit is "1 ' and '0' are repeated five times, and '1' instead of '0' is assigned to the 6th digit, so that '101011' may be assigned.

On the other hand, when the number (m) corresponding to the binary number of the compressed bit area (R2) is equal to the maximum value (2 ^c -1) (c is CompBitSize _{) of the compressed bit area (R 2} ) (S60b), the sine bit area ( R ₁ ) may be allocated to the decompression region by repeating m (S60f).

For example, consider a case where the size of the compressed bit ( CompBitSize ) is 4, the sine bit area ( R ₁ ) is '11', and the compressed bit area ( R ₂ ) is '1111'. Number corresponding to '1111' in the compressed bit region (R ₂₎ 15 is compression-bit region (R ₂₎ up to the ^(24-1) value, that is the same as in 15, in the decompression area, the bit '1''111111111111111' may be allocated by repeating 15 times.

Thereafter, the original bit string can be restored by allocating the bits of the sine bit region R ₁ and the residual bit region R ₃ before and after the decompression bit region, respectively (S60e).

In this case, if the residual bit area is determined by the number of bits corresponding to the size of the residual bit ( ResidualBitSize ), '0' or '1' may be filled as much as the number of bits of the original data in S60e. Alternatively, random bits may be filled.

Thus, one embodiment of the present invention, the digital repeater, the first bit stream (BS ₁₎ compression-bit region in the sign bit region (R ₁₎ a bit stream in a second bit stream (BS ₂₎ except for the in (R ₂ ), since it is a method of compressing and decompressing only the corresponding bits, it has advantages of high compression rate, low loss, and short delay time.

Referring back to FIG. 7 , the second DA converter 23 may convert the digital data restored by the second decompressor 26 into a baseband analog signal ( S70 ). At this time, the second DA conversion unit 23 separates the I bits (I ₀ , I ₁ , I ₂ , …) and the Q bits (Q ₀ , Q ₁ , Q ₂ , …) from the second decompression unit 26 . By receiving the digital data, it is possible to generate analog signals of I and Q signals.

Thereafter, the second baseband processing unit 22 may convert the baseband signal into an IF band signal ( S80 ).

The second frequency converter 21 may convert the signal of the IF band processed by the second baseband processor 22 into a signal of the RF band for transmission to the user terminal 3 (S90).

On the other hand, an uplink process in which a mobile communication signal is sequentially transmitted to the user terminal 3, the mobile communication repeater 1 and the base station 2 of the present invention, that is, from the user terminal 3 to the second unit 20 , from the second unit 20 to the first unit 10, and from the first unit 10 to the base station 2, respectively, the signal transmission process is a downlink process described with reference to FIGS. 2 and 7 . It may correspond to S10 to S90. Therefore, a description thereof will be omitted below.

9 is a schematic diagram for explaining an example of compressing and decompressing an I/Q signal in a mobile communication repeater of an embodiment of the present invention, wherein the I signal is I = -0.06669398V, the Q signal is Q = 0.12286503V, A case in which the target compression bit is set to 9 bits is shown. When the target compression bit is 9 bits, it means that digital data of the sum of 28 bits of IQ data is compressed into 18 bits of digital data and transmitted.

The input signal passing through the first AD conversion unit 13 is converted into a bit string in the form of two's complement, I=11110110010000, and may be converted into Q=00010001111110.

The first compression unit 15 may combine the I/Q bit string into one bit string _{to generate the first bit string BS 1} , and in one embodiment of the present invention, it is _{equal to 'BS 1} =1010101100101001011101010100' .

The first compression unit 15 may determine the size of the compression bit ( CompBitSize ) according to the level of the input signal. In the example of FIG. 9 , since the size of the input signal is -10 dBm or more, the size of the compression bit ( CompBitSize ) is 3 can be determined as

In addition, since the sine bit is '10', the number of consecutive 0s and 1s compressed bit count ( CompBitCount ) may be determined to be 5. Therefore, since the compressed bit count ( CompBitCount ) is smaller than 7, which is (2 ³ -1), a 3-bit binary number '101' corresponding to 5 _{can be allocated as the compressed bit area (R 2} ), and the sine bit area ( R ₁ ) is assigned '10'.

And the size ( ResidualBitSize ) of the residual bit area (R ₃ ) is determined to be 13 bits, '0010100101110' which is 13 bits from the 7th bit of the second bit string (BS _{2 ) is the residual bit area (R 3} ) may be assigned to

That is, the compressed data CB is determined to be 18 bits of '101010010100101110', and the first frame processing unit 17 may form a frame as shown in FIG. 6 and transmit it to the second unit 20 through the transmission line 30 .

The second transmission unit 28 of the second unit 20 may receive the frame data, and the second frame processing unit 27 may deframe it and provide the compressed data to the second decompression unit 26 . In this case, the deframed compressed data CB is 18 bits of '10101010100101110'.

The second decompression unit 26 divides the sine bit area R ₁ , the compressed bit area R ₂ , and the residual bit area R ₃ with reference to the size of the compressed bit ( CompBitSize ), and the compressed bit area Since the 5 corresponding to "101" in a binary number of (R ₂₎ is smaller than the maximum value of ^(23-1) of the compression bit region (R _2), after a sign bit "10" was repeated 5, 6 The th bit is assigned 1 to assign '101011' to the decompression bit area, and 13 bits after that are assigned to '0010100101110' of the residual bit area.

In addition, after allocating 21 bits (2 sine bit areas, 6 decompressed bit areas, and 13 residual bit areas), the remaining 7 bits among 28 bits are all assigned '0', or all By allocating '1' or by allocating random bits, the 28-bit third bit string BS ₃ may be completed.

In an embodiment of the present invention, BS ₃ =1010101100101001011101100000' by randomly allocating the last 7 bits. When this is divided into I bits and Q bits, I' = 11110110010100 and Q' = 00010001111000.

The second DA converter 23 may convert the IQ digital data to output analog signals I=-0.06622314V and Q=0.12220730V.

In the example of FIG. 9 , it can be seen that an error occurs after the fourth decimal place. According to the present invention, since the EVM representing the difference between the vector of the decoded signal and the original signal exhibits a performance of less than 2%, it can be seen that the actual commercial system can be applied.

* Figure 10 is an exemplary diagram showing the SQNR performance according to the input signal level of the digital repeater according to an embodiment of the present invention.

As shown in the figure, according to an embodiment of the present invention, a high signal-to-quantization noise ratio (SQNR) performance can be expected through the use of adaptive parameters, and a higher gain can be realized compared to the conventional partial bit method.

According to the present invention, there is no limitation on the target compressed transmission bit, and since it can be implemented in various ways according to the size of the compressed bit (CompBitSize), an organic compression algorithm may be applied.

In addition, since it is possible to determine the size of the optimal compression bit according to the level of the input signal, it is possible to expect high radio quality by minimizing the loss of information.

Although the embodiments according to the present invention have been described above, these are merely exemplary, and those of ordinary skill in the art will understand that various modifications and equivalent ranges of embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be defined by the following claims.

10: first unit 20: second unit
11, 21: frequency converter 12, 22: baseband generator
13, 23: AD conversion unit 14, 24: DA conversion unit
15, 25: compression unit 16, 26: decompression unit
17, 27: frame processing unit 18, 28: transmission unit

Claims (14)

A method of generating compressed data of a second bit string by compressing a first bit string obtained by converting an input signal into digital data,
allocating a sine bit, which is a first predetermined number of consecutive bits of the first bit string, to a first region of the second bit string;
counting the number of bits in which the sign bit is repeated in the bit string after the sign bit of the first bit string; and
allocating the counted number to the second region of the second bit string as a binary number having a length corresponding to the size of the compressed bit;
In the step of allocating to the second region, when the size of the compressed bit is the maximum value of the count of the second region, a binary number corresponding to the maximum value of the count of the second region with a length corresponding to the size of the compressed bit A data compression method for allocating to the second area.
According to claim 1,
and allocating the sign bit of the first bit string and the bits after the bit corresponding to the counted number to a third region of the second bit string according to the size of the remaining bits.
According to claim 1,
The data compression method further comprising the step of determining the size of the compression bit according to the input signal.
4. The method of claim 3,
The step of determining the size of the compression bit includes setting a value of a first size when the input signal is greater than or equal to a predetermined level, and setting a value of a second size greater than the first size when the input signal is below the predetermined level. Data compression method.
4. The method of claim 3,
In the step of determining the size of the compression bit, data of setting a value of a first size when the input signal is downlink, and setting a value of a second size larger than the first size when the input signal is uplink. compression method.
3. The method of claim 2,
In the step of allocating to the third region, when the size of the compressed bit is smaller than the maximum value of the count of the second region, after the sine bit and the bit corresponding to the next count of the counted number in the first bit string A data compression method for allocating bits of to the third area.
According to claim 1,
The data compression method further comprising generating a frame including the compressed data of the second bit string.
8. The method of claim 7,
The frame is a data compression method including information on the size of the compression bit.
A method of decompressing compressed data of a first bit string to generate digital data of a second bit string, the method comprising:
dividing the first bit string into a first area corresponding to a sine bit, which is a first predetermined number of consecutive bits, a second area corresponding to a compressed bit, and a third area corresponding to a residual bit;
repeating the sine bit by a number (m) corresponding to the binary number of the second region and assigning it to a fourth region of the second bit string; and
allocating a sine bit of the first region to a fifth region of the second bit string,
In the step of dividing into the fourth region, when m corresponds to the maximum value of the count of the second region, the sine bit is repeated as much as the maximum value and allocated to the fourth region.
10. The method of claim 9,
and allocating the remaining bits of the third region to a sixth region of the second bit string.
10. The method of claim 9,
The data decompression method further comprising the step of determining a size of a compression bit from a predetermined flag of a frame including the first bit string.
12. The method of claim 11,
When m is less than the maximum value of the count of the second region, data decompression further comprising allocating a bit different from the sine bit corresponding to the corresponding bit to the next bit of the bit corresponding to m Way.
In a mobile communication repeater that relays a signal between a base station and a user terminal,
a first conversion unit converting an input signal received from the base station or the user terminal into digital data to generate a first bit stream; and
and a compression unit that compresses the first bit string to generate compressed data of a second bit string,
The compression unit,
A sign bit, which is a first predetermined number of consecutive bits of the first bit string, is allocated to a first region of the second bit string, and in the bit string after the sign bit of the first bit string, the sign bit is repeated. Count the number and allocate the counted number to the second area of the second bit string as a binary number having a length corresponding to the size of the compressed bit,
When the size of the compressed bit is the maximum value of the count of the second region, a binary number corresponding to the maximum value of the count of the second region with a length corresponding to the size of the compressed bit is assigned to the second region communication repeater.
In a mobile communication repeater that relays a signal between a base station and a user terminal,
a frame processing unit for extracting compressed data of a first bit string from a frame received through a transmission line; and
and a decompression unit for decompressing the compressed data into data data of a second bit string,
The decompression unit,
In the first bit string, a number (m) corresponding to the binary number of the second area by dividing a first area corresponding to a sine bit, which is the first predetermined number of consecutive bits, and a second area corresponding to a compressed bit The sine bit is repeatedly allocated to the third region of the second bit string, and the sine bit of the first region is allocated to the fourth region of the second bit string, wherein m is the maximum of the count of the second region. If it corresponds to a value, the mobile communication repeater repeats the sign bit as much as the maximum value and allocates it to the third area.

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