JP2010118781A - Decoding device and decoding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire BCH information even when a communication environment is deteriorated in a decoding device such as a user terminal. <P>SOLUTION: The decoding device for decoding data obtained by encoding a series of N (N is a natural number) data in which the same information is written includes a decoding unit 23 which performs a process for receiving M (M is a natural number of M≤N) data out of the series of N data, performing decoding processing of the M data under supposition that the M data are data from the i-th data up to the (i+M-1)th (i is a natural number of i≤N-M+1) data, and when the decoding fails, performing the processing again by adding one to the value of i, and when decoding further fails, performing the processing again by further adding one to the value of i about all available values of i. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a decoding device and a decoding method.

Currently 3GPP (Third Generation
Partnership Project) LTE (Long
Time Evolution) is being standardized with a new communication method. One of the transport channels used in the communication method is BCH (Broadcast Channel). This channel is used for all UEs (User
Equipment) is a receiving channel, and TTI (Transmit Time) of 40 milliseconds (ms)
Interval). In addition, the transmission method has a feature. The same BCH information (hereinafter referred to as “BCH information”) transmitted in a 40 ms period is transmitted four times by 0.5 ms each by different encoded sequences. .

  The encoding processing is mainly CRC (Cyclic Redundancy Check) addition, convolutional encoding, rate-matching, and scrambling. Then, after the scrambling process, the encoded data is divided into four (see Non-Patent Document 1 or Non-Patent Document 2 for details of encoding). That is, CRC is first added to the data before division, convolutionally encoded, then rate-matching processing is performed, finally scrambling processing is performed, and then divided into four. .

  By dividing one piece of data encoded in this way into four parts, the scrambled sequence is different in the scramble process for each of the divided data. In the rate-matching process, the data extraction start position is different.

  In addition, what performed the encoding process to BCH information is transmitted as PBCH (Physical BCH). These four PBCHs all have the same BCH information, and BCH information can be decoded from only one. Therefore, each UE can acquire BCH information by receiving one of the four PBCHs.

3GPP TS 36.212 V8.3.0 pp. 35-36 3GPP TS 36.211 V8.3.0 pp. 52

  The reason why the same PBCH is transmitted four times is due to the consideration that the reception leakage is reduced in the UE due to the nature of broadcast information. Thus, the UE can acquire BCH information by receiving one portion of the PBCH transmitted four times. However, when the communication environment is bad, it may be difficult to receive even one out of four PBCHs transmitted. No specific proposal has yet been made for how to cope with such a poor communication environment.

  An object of the present invention is to provide a decoding apparatus and a decoding method that are obtained under such a background and can acquire BCH information even when the communication environment is bad. To do.

  The decoding device of the present invention is a decoding device that decodes data obtained by encoding a series of N (N is a natural number) data in which the same information is written. M (M is a natural number, M ≦ N) of data is received, and the M pieces of data are i-th to (i + M−1) -th (i is a series of N data). Decoding is performed on the assumption that i ≦ N−M + 1) as a natural number. When this decoding fails, the value of i is incremented by one and the processing is performed again. When decoding fails. , I is further provided with decoding means for performing the process of incrementing the value of i by one and performing the process again for all values that i can take.

  The decoding method of the present invention is a decoding method by a decoding device that decodes data obtained by encoding a series of N data in which the same information is written. Process of receiving M data of the data and decoding on the assumption that the M data are i-th to (i + M−1) -th of a series of N data When the decoding fails, the process is performed by incrementing the value of i by one and performing the process again. When the decryption fails, the process of incrementing the value of i by one and performing the process again is performed. This is for all possible values.

  Further, the program of the present invention is installed in an information processing apparatus, thereby realizing the function as the decryption means of the decryption apparatus of the present invention in the information processing apparatus.

  According to the present invention, BCH information can be acquired even when the communication environment is bad.

(Description of configuration of decoding apparatus according to embodiment of present invention)
A decoding apparatus according to an embodiment of the present invention will be described. In the description, a configuration of the base station 1 serving as an encoding device and a user terminal 2 serving as a decoding device will be described as an example. First, configurations of the base station 1 and the user terminal 2 will be described. FIG. 1 is a configuration diagram of the base station 1 and the user terminal 2. Note that the decoding of PBCH, which is standardized as 3GPP-LTE, will be described as a subject and will be described with reference to the drawings.

  The base station 1 includes an encoding unit 10, a modulation unit 11, a D / A conversion unit 12, and a transmission antenna 13. The user terminal 2 includes a reception antenna 20, an A / D conversion unit 21, a demodulation unit 22, and a decoding unit 23.

  In the encoding unit 10 of the base station 1, the encoding processing is mainly CRC addition, convolutional encoding, rate-matching, and scrambling. The transmission data is divided into four after the scrambling process. That is, CRC is first added to the data before division, convolutionally encoded, then rate-matching processing is performed, finally scrambling processing is performed, and then divided into four. .

  By dividing the data including the BCH information into four in this way, in each divided data, the Scramble sequence is different in the Scramble process. In the rate-matching process, the data extraction start position is different. The BCH information subjected to the encoding process is transmitted from the transmitting antenna 13 as PBCH as described above. The PBCH is obtained by dividing the original data into four, and four PBCHs are formed for one original data. Four PBCHs are formed as having the same BCH information.

  FIG. 2 is a configuration diagram of the decoding unit 23. In the description of the embodiment of the present invention, the decoding unit 23 will be mainly described. The decoding unit 23 includes a reception data memory 30 that temporarily stores the reception data demodulated by the demodulation unit 22, and a De-Scrambling unit that performs De-Scrambling (DSC) processing on the reception data output from the reception data memory 30. 31, Rate De-matching unit 32 that performs Rate De-matching processing on received data that has been subjected to De-Scrambling processing, and reception data that has been subjected to De-Scramble processing and De-matching processing are convolutionally encoded. A Viterbi decoding unit 33 that decodes data and performs CRC check, and a control unit 34 that controls these units.

(Description of operation of user terminal 2)
Next, the operation of the user terminal 2 will be described. In the user terminal 2, each PBCH is subjected to a plurality of different encodings, receives one of the PBCHs transmitted in a plurality of transmission units, and performs decoding processing corresponding to all possible encoding sequences for the PBCH. By doing so, BCH information and its transmission interval (TTI boundary) are detected in the shortest time. Even if the detection fails, the received data is stored in the received data memory 30 and is decoded as a unit of data when the next data is received, so that only data for one transmission unit is used. The detection rate can be increased over decoding.

  As a result, even if the communication environment is bad and the detection fails, the received data is held in the received data memory 30 and decoded as a unit of data when the next data is received. The detection rate can be increased as compared with the decoding using only the data. That is, since the PBCH is originally one encoded sequence, it is possible to decode the BCH information from one of the four consecutive PBCHs, and the four consecutive PBCHs can be grouped into the BCH. It is also possible to decrypt the information.

  In the base station 10, for example, first, a CPU (not shown) of the base station 10 inputs data to be transmitted to the encoding unit 10 as information bits. The encoding unit 10 performs CRC addition, convolutional encoding, rate-matching, scrambling, and the like on the input information bits.

  The modulation unit 11 modulates the input encoded data and outputs transmission data that is data after modulation to the D / A conversion unit 12. The D / A converter 12 converts the transmission data output from the modulator 11 from a digital signal to an analog signal. The transmission data converted into an analog signal is transmitted via the transmission antenna 13.

  The user terminal 2 on the receiving side receives data transmitted from the transmission antenna 13 of the base station 1 via the reception antenna 20. However, it should be noted that the data received by the receiving antenna 20 is influenced by noise when propagating in space after being output from the transmitting antenna 13.

  Data received by the receiving antenna 20 is input to the A / D converter 21. The A / D converter 21 converts the input data from an analog signal to a digital signal. The A / D converter 21 outputs the converted digital signal to the demodulator 22. The demodulator 22 demodulates the data output from the A / D converter 21. The demodulator 22 outputs the received data obtained by demodulation to the decoder 23.

  The decryption unit 23 temporarily stores the received data in the reception data memory 30. The data temporarily stored in the reception data memory 30 is used for a decryption process to be described later. The received data memory 30 temporarily holds a series of four PBCHs. At this time, if decoding is successful with the first, second, or third PBCH in the decoding process described later, the remaining PBCH is discarded because it is useless.

  Further, the De-Scrambler 31 performs a De-Scrambling (DSC) process on the reception data output from the reception data memory 30. The rate de-matching unit 32 performs rate de-matching processing on the received data that has been subjected to the de-scrambling processing. Finally, the Viterbi decoding unit 33 decodes the convolutionally encoded data for the reception data that has been subjected to the De-Scrambling process and the De-matching process, and performs a CRC check. A processing circuit such as a CPU (Central Processing Unit) in the subsequent stage performs predetermined processing using the decoded data obtained as a result.

(Description of operation of decryption unit 23)
Next, the operation of the decoding unit 23 will be described using the operation examples of FIGS. 3 to 9 and the timing chart of FIG. Each of the leftmost arrows in FIGS. 3 to 9 indicates the decoding start position.

  In the PBCH, the encoded data is divided into four, and one slot (one slot is 0.5 ms) is transmitted in each of four consecutive frames (one frame is 10 ms).

  In the embodiment of the present invention, the method of using data differs depending on the number of received PBCH frames (hereinafter referred to as “the number of received frames”). In FIG. 3, first, when the number of received frames is 1, decoding is performed on the assumption that the data D1 for one frame is each of data divided into four. Which frame of the data divided into four frames has equal probability. Therefore, for example, decoding is first attempted as the first division (hereinafter referred to as frame # 0), and then decoding is attempted as the second division (hereinafter referred to as frame # 1). The third division is frame # 2, and the last division is frame # 3. Since the transmission data is one of these four frames, if the communication environment is good, a CRCOK is obtained as a result of one of the four decoding processes, and the decoding is successful. Thereby, the BCH information and the transmission interval can be known only from the data D1 received first. Note that the number of transmission antennas can also be known by decoding the BCH information.

  However, when the communication environment is poor, there is a case where error correction cannot be performed sufficiently with the data D1 for one frame, and CRCOK cannot be obtained. In that case, in the embodiment of the present invention, since the received data D1 is held in the received data memory 30, if the CRCOK is not obtained, the holding is continued and the reception of the data D2 of the next frame is awaited. . When the data D2 of the next frame is obtained, the received data is for two frames. Since the data D1 and D2 of each frame are originally one encoded data, the data D1 and D2 for two consecutive frames are a part thereof. Therefore, two frames can be decoded as a single piece of data.

An example of this operation is shown in FIG. That is, decoding is performed assuming that data D1 received one frame before is frame # 0, the current received frame is frame # 1, and the like. However, assuming that the current received frame is frame # 0, the data D1 one frame before is frame # 3 having other BCH information, and therefore, no batch decoding is performed. If the usage method of the data D1 of the previous frame and the current data D2 is expressed as “(received data of the previous frame, current received data)”, decoding is performed as the following combination.
Assuming frame # 0 (not used, frame # 0),
Assuming frame # 1 (frame # 0, frame # 1),
Assuming frame # 2 (frame # 1, frame # 2),
Assuming frame # 3 (frame # 2, frame # 3)
As a result, by using the data D1 and D2 for two frames, it is possible to perform decoding more resistant to deterioration of the reception environment than using only one frame of data.

When the number of received frames is 3, data D1, D2, D3 for 3 frames is used, and when the number of received frames is 4, data D1, D2, D3, D4 for 4 frames are used, but from frame # 0 The data assumed before is not used. As in the case where the number of received frames is 2, the usage of each received data is expressed as “(received data before 3 frames, received data before 2 frames, received data before 1 frame, current received data)”. In the case where the number of received frames is 3, as shown in FIG.
Assuming frame # 0 (not used, not used, frame # 0),
Assuming frame # 1 (not used, frame # 1, frame # 2),
Assuming frame # 2 (frame # 0, frame # 1, frame # 2),
Assuming frame # 3 (frame # 1, frame # 2, frame # 3)
It becomes.

In the number of received frames 4, as shown in FIG.
Assuming frame # 0 (not used, not used, not used, frame # 0),
Assuming frame # 1 (not used, not used, frame # 0, frame # 1),
Assuming frame # 2 (not used, frame # 0, frame # 1, frame # 2),
Assuming frame # 3 (frame # 0, frame # 1, frame # 2, frame # 3)
It becomes.

  When the data D5, D6,... After the fifth frame is received, the control unit 34 overwrites old received data with new received data, and the received data memory 30 always holds the latest four frames. Keep it. Along with this, the decoding start position is changed as shown in FIGS.

  Generalizing the operations described with reference to FIGS. 3 to 8, in a decoding apparatus that decodes data obtained by encoding a series of N information (N is a natural number) in which the same information is written. When M (M is a natural number, M ≦ N) data of a series of N data is received, the M data are the i-th to (i + M) th of the series of N data. -1) Decoding is performed assuming that i is a natural number and i ≦ N−M + 1. When this decoding fails, the value of i is incremented by one and the processing is performed again. Further, when decoding fails, the process of incrementing the value of i by one and performing the process again is performed for all values that i can take. Furthermore, j (j ≦ (M−1)) pieces of data among the received M pieces of data are data included in a series of N pieces of data transmitted last time, and a series of pieces of data transmitted this time. It is assumed that it is not part of the data and is not used, and the remaining (M−j) pieces of data are decoded as data including the first data for all possible values of j. It will be.

  FIG. 9 shows a decoding process when a part of continuous received data is not valid. If there is an invalid part, the data is used as intermediate data “0” which is neither “−1” nor “1”. However, the received data takes a value between “−1” and “1”. Thereby, even if a part of four consecutive frames is lost, decoding can be performed with the remaining received data.

  Even if the CRC check can be confirmed, if the decoding result cannot be determined by the likelihood information such as the path metric obtained during Viterbi decoding, the decoding is not completed and the next frame data is decoded. Processing such as continuation may be performed. Such a case can be dealt with by using some frames as intermediate data as shown in FIG. If the CRC check is NG but there is a frame likelihood with a high likelihood in the previous decoding, the frame with a high likelihood is not used in the previous decoding without performing decoding based on other frame assumptions. Decoding only by assumption may be performed. That is, the natural number i is not necessarily incremented one by one, and the decoding attempt may be started from a frame assumption that has been successfully decoded with reference to the likelihood in the previous decoding.

  FIG. 10 shows a control unit 34, a De-scrambling unit (DSC) 31, a Rate De-matching unit (RDM) 32, and a Viterbi decoding unit (VTA) 33 when decoding data for four frames (see FIG. 6). Is a timing chart. The length of the band in the horizontal direction is the length of processing time for each part. The band of frames 40, 41, 42, and 43 shows the decoding operation assuming that the frames are # 0, # 1, # 2, and # 3, respectively. In frame 40, the assumed frame # 0 is processed, The frame 41 processes assumed frames # 0 and # 1, the frame 42 processes assumed frames # 0, # 1, and # 2, and the frame 43 processes assumed frames # 0, # 1, # 2, and # 3. Process. Thus, the larger the frame number, the longer the processing time because more received data is used.

(Explanation of a flowchart showing the operation of the decoding unit 23)
Next, the operation of the decoding unit 23 will be described using the flowcharts shown in FIGS. Here, four types of modes of 1 frame mode, 2 frame mode, 3 frame mode, and 4 frame mode are provided. That is, the mode for receiving only one frame of the four PBCHs is the 1-frame mode, and the mode for receiving two frames of the four PBCHs is the two-frame mode. Similarly, a mode for receiving three frames of the four PBCHs is a three-frame mode, and a mode for receiving all the frames of the four PBCHs is a four-frame mode.

  The decoding unit 23 first attempts to decode in the 1-frame mode, and if that is not possible, the decoding unit 23 sequentially shifts to the 2-frame mode, the 3-frame mode, and the 4-frame mode. Thus, the number of received frames is increased according to the deterioration of the communication environment. According to this, since the decoding can be performed with the minimum number of frames depending on the quality of the communication environment, the decoding can be performed with the minimum processing time.

  That is, the decoding unit 23 first attempts decoding in the 1 frame mode. If decoding in this one-frame mode is successful, BCH information can be acquired in the shortest time. Note that the decoding in the 1-frame mode is successful when the communication environment is good. That is, if the communication environment is good, there is little noise in the transmission path, and almost no BCH information code error occurs. Therefore, when the decoding unit 23 decodes the convolutionally encoded data, it is sufficient if there is one frame of code used for error correction. On the other hand, when the communication environment is not good, there are many noises in the transmission path and many BCH information code errors occur. Therefore, when the decoding unit 23 decodes the convolutionally encoded data, the code used for error correction is not enough for one frame. Thereby, when the communication environment is not good, it is necessary to receive two frames or more.

  FIG. 11 is a flowchart showing the operation of the 1-frame mode in the decoding unit 23. When receiving one frame (step S1), the decoding unit 23 first attempts to decode assuming that the received one frame is frame # 0 (step S2). Here, if the decryption unit 23 succeeds in decryption (No in step S3), the data is output (step S11), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S3), the decoding is attempted assuming that one received frame is frame # 1 (step S4). Here, if the decryption unit 23 succeeds in decryption (No in step S5), the data is output (step S11), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S5), the decoding is attempted assuming that one received frame is frame # 2 (step S6). If the decryption unit 23 succeeds in decryption (No in step S7), the data is output (step S11), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S7), the decoding is attempted assuming that the received one frame is frame # 3 (step S8). If the decryption unit 23 succeeds in decryption (No in step S9), the data is output (step S11), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S9), the decoding unit 23 transitions to the 2-frame mode (step S10).

  FIG. 12 is a flowchart showing the operation in the 2-frame mode in the decoding unit 23. When the decoding unit 23 fails in the decoding in the 1-frame mode shown in FIG. 11, the decoding unit 23 executes the 2-frame mode shown in FIG.

  When the decoding unit 23 receives two frames (step S20), first, it is assumed that the first frame of the two received frames is the frame # 3 of the previously transmitted data. Decoding is attempted on the assumption that the second frame is frame # 0 and not used (step S21). If the decryption unit 23 succeeds in decryption (No in step S22), the data is output (step S30), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S22), the first frame of the two received frames is frame # 0, and the second frame is frame # 1. Decoding is attempted on the assumption (step S23). If the decryption unit 23 succeeds in decryption (No in step S24), the data is output (step S30), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S24), the first frame of the two received frames is the frame # 1, and the second frame is the frame # 2. Decoding is attempted on the assumption (step S25). Here, if the decryption unit 23 succeeds in decryption (No in step S26), the data is output (step S30), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails to decode (Yes in step S26), the first frame of the two received frames is frame # 2, and the second frame is frame # 3. Decoding is attempted on the assumption (step S27). Here, if the decryption unit 23 succeeds in decryption (No in step S28), the data is output (step S30), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S28), the decoding unit 23 transitions to the 3-frame mode (step S29).

  FIG. 13 is a flowchart showing the operation in the 3-frame mode in the decoding unit 23. When the decoding unit 23 fails in decoding in the two-frame mode shown in FIG. 12, the decoding unit 23 executes the three-frame mode shown in FIG.

  When the decoding unit 23 receives three frames (step S40), the first frame of the received three frames is the frame # 2 of the data transmitted last time, and the second frame The frame is not used on the assumption that it is frame # 3 of the previous data, and decoding is attempted assuming that the third frame is frame # 0 (step S41). Here, if the decryption unit 23 succeeds in decryption (No in step S42), the data is output (step S50), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S42), the first frame of the received three frames is assumed to be the frame # 3 of the previous data and is not used. Decoding is attempted on the assumption that the second frame is frame # 0 and the third frame is frame # 1 (step S43). If the decryption unit 23 succeeds in decryption (No in step S44), the data is output (step S50), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S44), the first frame of the three received frames is frame # 0, and the second frame is frame # 1. Yes, decoding is attempted assuming that the third frame is frame # 2 (step S45). If the decryption unit 23 succeeds in decryption (No in step S46), the data is output (step S50), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S46), the first frame of the three received frames is the frame # 1, and the second frame is the frame # 2. Yes, decoding is attempted assuming that the third frame is frame # 3 (step S47). If the decryption unit 23 succeeds in decryption (No in step S48), the data is output (step S50), and the process is terminated (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S48), the decoding unit 23 transitions to the 4-frame mode (step S49).

  FIG. 14 is a flowchart showing the operation of the 4-frame mode in the decoding unit 23. When the decoding unit 23 fails in decoding in the 3-frame mode shown in FIG. 13, the decoding unit 23 executes the 4-frame mode shown in FIG. If decoding is not successful in the 4-frame mode, it can be said that the communication environment is so bad that communication must be interrupted.

  When the decoding unit 23 receives four frames (step S60), the first frame of the received four frames is the frame # 1 of the previous data, and the second frame is the previous frame. The third frame is unused, assuming that it is frame # 3 of the previous data, and decoding is attempted assuming that the fourth frame is frame # 0 (step S61). If the decryption unit 23 succeeds in decryption (No in step S62), the data is output (step S71), and the process is terminated (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S62), the first frame of the received four frames is assumed to be the frame # 2 of the previous data and is not used. The second frame is assumed to be unused, assuming that it is frame # 3 of the previous data, the third frame is assumed to be frame # 0, and the fourth frame is assumed to be frame # 1. Then, decoding is attempted (step S63). If the decryption unit 23 succeeds in decryption (No in step S64), the data is output (step S71), and the process is terminated (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S64), the first frame of the received four frames is assumed to be the frame # 3 of the previous data and is not used. Decoding is attempted on the assumption that the second frame is frame # 0, the third frame is frame # 1, and the fourth frame is frame # 2 (step S65). If the decryption unit 23 succeeds in decryption (No in step S66), the data is output (step S71), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S66), the first frame of the received four frames is the frame # 0, and the second frame is the frame # 1. Yes, decoding is attempted on the assumption that the third frame is frame # 2 and the fourth frame is frame # 3 (step S67). If the decryption unit 23 succeeds in decryption (No in step S68), the data is output (step S71), and the process ends (Finish).

  On the other hand, if the decoding unit 23 fails in decoding (Yes in step S68), the decoding unit 23 determines that the new frame received next is the oldest among the four frames that have already been received. The frame is overwritten (step S69). Subsequently, the decoding unit 23 sets the decoding start position of the four frames as the next frame of the overwritten frame (step S70). Then, the process returns to step S61, and the subsequent processing is executed again.

  Further, in the flowcharts of FIGS. 11 to 14, it has been described that the decoding is started from the 1-frame mode and the process finally proceeds to the 4-frame mode. However, if there is a frame assumption with a high likelihood in the previous decoding, the decoding based on the frame assumption only with a high likelihood is not performed in the previous decoding without performing the decoding based on other frame assumptions. May be.

  For example, in the previous three-frame mode, although decoding was not successful, it is assumed that the likelihood of decoding based on the frame assumption of frame # 0, frame # 1, and frame # 2 is high. If so, in the next four-frame mode to which data of one frame is further added, the processing is started from the assumption of frame # 0, frame # 1, frame # 2, and frame # 3. According to this, in FIG. 14, “decoding as frame # 0”, “decoding as frame # 0 and frame # 1” and “decoding as frame # 0, frame # 1 and frame # 2” are performed. The probability of successful decoding in a short time may increase. That is, it can be said that the frame assumption having a high likelihood in the previous decoding has a high probability of successful decoding if there is a little more data. If the process is started from “decode as frame # 0” on the insulator ruler without taking this into consideration, there is a high probability that decoding will fail, and time may be wasted. Therefore, by following the previous experience with frame assumptions, the probability of successful decoding in a shorter time becomes higher than when all frame assumptions are attempted with the lever ruler.

(Example of the program)
Next, an example of a program that, when installed in the information processing apparatus, realizes the function as the decoding unit 23 of the user terminal 2 (decoding apparatus) according to the embodiment of the present invention in the information processing apparatus will be described. To do. Here, the information processing apparatus is, for example, a general-purpose computer apparatus, and includes a CPU, a DSP (Digital Signal Processor), or a microprocessor.

  By recording the program of this embodiment on a recording medium, the information processing apparatus can install the program of this embodiment using this recording medium. Or the program of a present Example can also be installed in an information processing apparatus directly from the server holding the program of a present Example via a network.

  Thereby, the function (De-Scrambling part 31, Rate De-matching part 32, Viterbi decoding part 33, etc.) of the decoding part 23 of the user terminal 2 is realizable using information processing apparatus. Note that other functions that can be realized by software may also be realized by the program of this embodiment.

  The program of this embodiment includes not only a program that can be directly executed by the information processing apparatus but also a program that can be executed by being installed on a hard disk or the like. Also included are those that are compressed or encrypted.

(Explanation of effects in the embodiment of the present invention)
The first effect is that information can be acquired in the shortest time. The reason is that the decoding process corresponding to all possible encoding formats is performed on the reception data for one frame.

  The second effect is that a higher detection rate than that obtained by decoding data for one frame can be obtained. The reason is that the received data is held, and the received data held when the next data is received and the newly received data are decoded as one continuous data. Moreover, even when it is determined that one or more of the plurality of received frames are not valid, decoding can be performed without being affected by the data.

(Modification)
The embodiment of the present invention can be variously modified without departing from the gist thereof. For example, in FIG. 1, the base station 1 and the user terminal 2 are illustrated and connected between them by a wireless line. However, replacing the wireless line in FIG. 1 with a wired line does not depart from the gist of the embodiment of the present invention. Furthermore, although the base station 1 and the user terminal 2 are illustrated, the base station 1 may be replaced with any type of encoding device, and the user terminal 2 may be replaced with any type of decoding device.

  In the above-described embodiment, decoding of PBCH, which is standardized as 3GPP-LTE, is described as a theme. However, the PBCH in the embodiment of the present invention can be replaced with any data obtained by encoding a series of N data in which the same information is written. Various methods can be applied to the encoding method and the decoding method.

It is a figure for demonstrating the decoding apparatus which concerns on embodiment of this invention, and is a block diagram of the user terminal used as a base station and a decoding apparatus. It is a block block diagram of the decoding part of the user terminal of FIG. It is a figure explaining the operation | movement which decodes one received frame in the decoding part of FIG. It is a figure explaining the operation | movement which decodes two received frames in the decoding part of FIG. It is a figure explaining the operation | movement which decodes three received frames in the decoding part of FIG. It is a figure explaining the operation | movement which decodes four received frames in the decoding part of FIG. It is a figure explaining the operation | movement which decodes five received frames in the decoding part of FIG. It is a figure explaining the operation | movement which decodes six received frames in the decoding part of FIG. It is a figure which shows a mode that the frame of a low likelihood is decoded as an intermediate value in the decoding part of FIG. It is a figure which shows the time chart which shows the operation | movement of each part at the time of decoding four received frames in the decoding part of FIG. It is a flowchart which shows the operation | movement of decoding in the decoding part of FIG. 2, and is a figure which shows operation | movement of 1 frame mode. It is a flowchart which shows the operation | movement of decoding in the decoding part of FIG. 2, and is a figure which shows operation | movement of 2 frame mode. It is a flowchart which shows the operation | movement of decoding in the decoding part of FIG. 2, and is a figure which shows operation | movement of 3 frame mode. It is a flowchart which shows the operation | movement of decoding in the decoding part of FIG. 2, and is a figure which shows operation | movement of 4 frame mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base station (encoding apparatus), 2 ... User terminal (decoding apparatus), 10 ... Encoding part, 11 ... Modulation part, 12 ... D / A conversion part, 13 ... Transmission antenna, 20 ... Reception antenna, 21 A / D conversion unit, 22 ... demodulation unit, 23 ... decoding unit (decoding means), 30 ... received data memory, 31 ... De-Scrambling unit, 32 ... Rate De-matching unit, 33 ... Viterbi decoding unit, 34 ... Control unit

Claims (13)

In a decoding apparatus for decoding data obtained by encoding a series of N data (N is a natural number) data in which the same information is written,
M (M is a natural number, M ≦ N) of the series of N data is received, and the M pieces of data are from i-th to (i + M) of the series of N data. -1) Decoding is performed assuming that i is a natural number and i ≦ N−M + 1. When this decoding fails, the value of i is incremented by one and the above process is performed again. And when the decoding fails, the decoding is further provided with decoding means for performing the process of incrementing the value of i by one and performing the process again for all values that i can take. Device. The decoding device according to claim 1, wherein
The decoding means regards j (j ≦ (M−1)) pieces of data among the received M pieces of data as data included in a series of N pieces of data transmitted last time. A decoding apparatus characterized by including a step of performing a decoding process using the remaining (M−j) data as data including the first data, which is not used. The decoding device according to claim 1 or 2,
The decoding apparatus according to claim 1, wherein the decoding means performs decoding only on data with high likelihood among the i-th to (i + M-1) -th data. The decoding device according to claim 3, wherein
The decoding apparatus according to claim 1, wherein the likelihood is based on likelihood information obtained during Viterbi decoding. The decoding device according to any one of claims 1 to 4,
The decoding device, wherein the decoding means increases the value of M according to deterioration of a communication environment. The decoding device according to any one of claims 1 to 5,
The decoding apparatus according to claim 1, wherein the decoding means performs decoding only for an i-th frame assumption having a high likelihood in the previous decoding. In a decoding method by a decoding apparatus that decodes data obtained by encoding a series of N data (N is an integer of 2 or more) in which the same information is written,
M (M is a natural number, M ≦ N) of the series of N data is received, and the M pieces of data are from i-th to (i + M) of the series of N data. -1) Decoding is performed assuming that i is a natural number and i ≦ N−M + 1. When this decoding fails, the value of i is incremented by one and the above process is performed again. A decoding method characterized in that when the decoding fails, the value i is incremented by one and the process is performed again for all values that i can take. The decoding method according to claim 7, wherein
Of the received M data, j (j ≦ (M−1)) data is regarded as data included in a series of N data transmitted last time, and is not used. A decoding method comprising a step of performing a decoding process using (M−j) pieces of data as data including the first data. The decoding method according to claim 7 or 8,
A decoding method characterized in that decoding is performed only on data with high likelihood among the i-th to (i + M-1) -th data. The decoding method according to claim 9, wherein
The decoding method according to claim 1, wherein the likelihood is based on likelihood information obtained during Viterbi decoding. The decoding method according to any one of claims 7 to 10,
A decoding method, wherein the value of M is increased in accordance with deterioration of a communication environment. The decoding method according to any one of claims 7 to 11,
A decoding method, wherein decoding is performed only on the i-th frame assumption that has a high likelihood in the previous decoding.   A program that, when installed in an information processing apparatus, causes the information processing apparatus to realize the function of the decoding unit of the decoding apparatus according to any one of claims 1 to 6.

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