WO2013000333A1

WO2013000333A1 - Deciphering method and device

Info

Publication number: WO2013000333A1
Application number: PCT/CN2012/074853
Authority: WO
Inventors: 杜文亮
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-28
Filing date: 2012-04-27
Publication date: 2013-01-03
Also published as: CN102857233B; CN102857233A

Abstract

Disclosed are a deciphering method and device. The deciphering method includes: a first decipherer deciphering soft information about a physical downlink control channel to obtain a first deciphering result and attribute information about physical downlink control information; a second decipherer deciphering the soft information according to the attribute information about the physical downlink control information to obtain a second deciphering result; comparing the first deciphering result and the second deciphering result, and determining that the first decipherer has successfully deciphered the soft information if the first deciphering result is consistent with the second deciphering result. The present invention can improve the deciphering accuracy of the physical downlink control channel (PDCCH) and the system performance of the user equipment.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a decoding method and apparatus. BACKGROUND OF THE INVENTION The 3rd Generation Partnership Project (3GPP) proposes a Long Term Evolution (LTE) system for 3GPP over-the-air technology. LTE systems need to achieve lower latency, higher user data rates, greater system capacity, greater coverage and lower cost, and support for multiple antenna technologies. In order to meet its high-rate transmission requirements for real-time service, broadcast and multicast services, in the aspect of channel coding and decoding technology, the LTE system uses tail biting convolutional coding and Turbo coding. The tail biting convolutional code takes the last few bits of the data block to be encoded as the initial state of the registers in the encoder, forcing each codeword to have the same state at the beginning and end. Although this coding method improves the coding efficiency, since the decoder does not know the initial state of the encoder, the complexity of decoding is increased. Since the decoder does not have any information about the initial state of the trellis diagram, Maximum Likelihood (ML) decoding requires that each of the states be treated as its start and end states for each individual Viterbi decoding. Finally, choose the path for the best metric. Due to the high computational complexity of ML decoding, many low-complexity decoding algorithms have been proposed. These decoding algorithms are mostly based on the cyclic Viterbi algorithm (CVA). The CVA uses the loopback characteristic of the tail bit encoding to repeat the received data block several times to form a long sequence for Viterbi decoding until the stop condition is satisfied. In the mobile communication with rapidly changing channel conditions, the received tail-biting convolutional coded data may have a large error, which deteriorates the convergence of the CVA algorithm and increases the variability of the decoding time. In this case, the two-step Viterbi algorithm (TSVA) is proposed to make the decoding time fixed. TSVA performs two different Viterbi decodings. The first step estimates the state with the largest likelihood value, and the second step uses the previously estimated state as the start and end state to perform a conventional Viterbi decoding, but the performance of the TSVA algorithm is not high. Regardless of the length of the data, the performance of the ML algorithm is higher than other algorithms, but such an advantage comes at the cost of computational complexity. Because the computational complexity of the ML algorithm grows exponentially according to the number of registers in the encoder, a large delay is generated for a communication system with high real-time requirements. For LTE systems, the amount of traffic channel data that can be supported is large. In the case of a large amount of data, if the ML algorithm is used for the control channel of each Transmission Time Interval (TTI), there are two problems: a) Data calculation takes a lot of processing time, affecting the entire system. Performance; b) Failure to verify the detected information may result in a higher rate of false positives. For the problem of long calculation time and high false detection rate in the related art, an effective solution has not been proposed yet. SUMMARY OF THE INVENTION The present invention provides a decoding method and apparatus to solve at least one of the above problems. According to an aspect of the present invention, a decoding method is provided, including: decoding, by a first decoder, soft information of a physical downlink control channel to obtain attribute information of a first decoding result and physical downlink control information; The second decoder decodes the soft information according to the attribute information of the physical downlink control information, to obtain a second decoding result, and compares the first decoding result with the second decoding result, where If the first decoding result is consistent with the second decoding result, determining that the first decoder successfully decodes the soft information. Preferably, the attribute information includes: a location where the physical downlink control information is detected, and a length of the physical downlink control information. Preferably, the attribute information further includes: a control channel particle aggregation degree. Preferably, the first decoder decodes the soft information of the physical downlink control channel, and obtains the first decoding result and the attribute information of the physical downlink control information, including: the first decoder is configured to the soft The information is subjected to full blind detection, and the first decoding result and the attribute information of the physical downlink control information are obtained. Preferably, the method further includes: determining, when the first decoding result is inconsistent with the second decoding result, that the first decoder generates a false check when decoding the soft information . According to another aspect of the present invention, a decoding apparatus is provided, including: a first decoding unit configured to decode soft information of a physical downlink control channel to obtain a first decoding result and physical downlink control information The second decoding unit is configured to decode the soft information according to the attribute information of the physical downlink control information to obtain a second decoding result, and the comparing unit is configured to set the first decoding result And the second decoding And comparing, the determining unit is configured to: when the comparing unit determines that the first decoding result is consistent with the second decoding result, determining that the first decoder translates the soft information The code is successful. Preferably, the first decoding unit is configured to perform full blind detection on the soft information to obtain attribute information of the first decoding result and the physical downlink control information. Preferably, the determining unit is further configured to: when the comparing unit determines that the first decoding result is inconsistent with the second decoding result, determine that the first decoding unit performs the soft information A misdetection occurred during decoding. Preferably, the attribute information includes: a location where the physical downlink control information is detected, and a length of the physical downlink control information. Preferably, the attribute information further includes: a control channel particle aggregation degree. Through the invention, different decoders are used for secondary decoding, and the two decoding results are compared, so that the false detection rate is reduced, and the time occupied by the data calculation is not increased, thereby improving the physical downlink control channel (PDCCH). The accuracy of the decoding and the system performance of the user equipment. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 is a flowchart of a decoding method according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a decoding process according to an embodiment of the present invention; FIG. 3 is a schematic diagram of encoding processing according to an embodiment of the present invention; 4 is a flowchart of a decoding process in accordance with a preferred embodiment of the present invention; and FIG. 5 is a block diagram showing the structure of a decoding apparatus according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. In the LTE system, the error check of the downlink control information (Downlink Control Information, DCI for short) is completed by the cyclic redundancy check (CRC) in the DCI transmission information. Assuming that the valid bits of the PDCCH are ^, ^, ^, ^, ..., ^, then the check bits are _{1 2 3} , ..., _ ₁ , where A is the payload number of the PDCCH, and L is the school. The number of check digits, preferably, the DCI information check bit length of the control channel is set to L=16.

gcRci6(D) = [D ₁₆ + D ₁₂ + D ₅ + l], CRC length L = 16, input bit and polynomial after a certain operation to get the output sequence „ ₂ , , ..., _,, B = A+ L Since the check bit of the DCI information is 16 bits, under ideal conditions, the probability of false detection when the decoder decodes the soft information of the DCI is 1/2 ¹⁶ . However, it is impossible to completely achieve this due to the performance of the decoder. The ideal requirement causes the false detection rate of DCI to change with the performance of the decoder in practical applications. Therefore, considering the complexity of algorithms such as ML and CVA, in order to greatly reduce the false detection rate of the decoder, the present invention is implemented. The example provides a decoding method, which uses two decoders to perform decoding twice. Figure 1 is a flowchart of a decoding method according to an embodiment of the present invention, as shown in Figure 1, in the embodiment of the present invention. The decoding processing flow mainly includes the following steps S102 to S106. Step S102, the first decoder decodes the soft information of the physical downlink control channel, and obtains the first decoding result and the physical downlink control information (DCI). Attribute information, where the physical downlink control channel (PDCCH) The soft information may be obtained by the decoding pre-processing unit. In a preferred embodiment of the present invention, the attribute information of the DCI includes but is not limited to: the length of the DCI, the location at which the DCI is detected. Another preferred implementation of the embodiment of the present invention In the mode, the attribute information of the DCI further includes at least one of the following: a size of the DCI, a control channel element (CCE) degree of aggregation, and the like, where the first decoder can completely blind the soft information of the PDCCH. Detecting, thereby obtaining the first decoding result and the attribute information of the DCI. In step S104, the second decoder decodes the soft information according to the attribute information of the physical downlink control information to obtain a second decoding result. The decoder decodes the corresponding soft information again based on the attribute information of the DCI obtained by the first decoder, thereby obtaining a second decoding result. For example, the second decoder may perform the first decoding according to the first decoding. The device detects the position and length of the DCI, and detects the DCI of the same length at the same position of the soft information of the PDCCH, thereby obtaining a second detection result. Step S106, comparing the first decoding result with the second decoding result, and determining, in the case that the first decoding result is consistent with the second decoding result, determining the first decoding. The device successfully decodes the soft information. In the embodiment of the present invention, if the first decoding result is inconsistent with the second decoding result, determining that the first decoder in step S102 decodes the soft information occurs, that is, the first The decoder decodes the soft information error. In a preferred embodiment of the present invention, the first decoding result may be a CRC check code of the DCI detected by the first decoder, and the second decoding result may be a CRC of the DCI detected by the second decoder. Check code. The above method provided by the embodiments of the present invention utilizes the combined advantages of the decoders, so that in the case of low decoding accuracy, the second decoder is performed by using different decoders, and the two decoding results are performed. Compared, the false detection rate can reach 1/2 ³² under ideal conditions, which greatly improves the accuracy of UE PDCCH blind detection and UE system performance. 2 is a flow diagram of a decoding process in accordance with a preferred embodiment of the present invention. As shown in FIG. 2, in a preferred embodiment of the present invention, the decoder A decodes the soft information (Soft lnfo) of the control channel and outputs DCI information. The output DCI information includes: a DCI length, a location where the DCI is detected, and a size information of the DCI. Based on the DCI information output by the decoder A, the decoder B detects information such as the position of the DCI, the degree of CCE aggregation, and the like, and decodes the corresponding soft information again. Then, the subsequent processing is performed, that is, the decoding result of the decoder B is compared with the decoder A result, and the two are consistent. When the CRC check is passed, the control information is successfully detected. No Bay U, it is considered that the decoder A is falsely detected. 3 is a schematic diagram of an encoding process in accordance with a preferred embodiment of the present invention. As shown in FIG. 3, in the preferred embodiment, for a tail-biting convolutional code with a constraint length of 7 and a code rate of 1/3, the initial value of the encoder's shift register is set to the last 6 pieces of information of the input stream. The value corresponding to the bit is such that the initial and final states of the shift register are the same. Therefore, in the preferred embodiment, with the shift register representing the encoder, the initial value of the shift register is set to: = c ( _K + where the output stream of the encoder, and ²⁾ correspond to the first and second, respectively. And the third check data stream. 4 is a flow chart of a decoding process in accordance with a preferred embodiment of the present invention. As shown in FIG. 4, in a preferred embodiment of the present invention, the decoding processing flow mainly includes the following steps S402 to S412. Step S402, obtaining soft information of the PDCCH control channel. For example, it can be acquired by the decoding pre-processing unit. Step S404, the decoder A performs full blind detection on the soft information, and outputs the detected DCI detailed information and the decoding result. Step S406, based on the DCI detailed information outputted in step S404, the decoder B performs secondary decoding on the soft information to obtain a decoding result. Step S408, comparing the decoding result obtained by the decoder A with the decoding result obtained by the decoder B, determining whether the two are consistent, if yes, executing step S410, if not, performing step S412; step S410 The feedback decoder A successfully detects the soft information of the PDCCH. In step S412, the feedback decoder A is erroneously detected. Corresponding to the foregoing method, the embodiment of the present invention further provides a decoding apparatus, which may be used to implement the foregoing decoding method provided by the embodiment of the present invention. FIG. 5 is a schematic structural diagram of a decoding apparatus according to an embodiment of the present invention. As shown in FIG. 5, the apparatus mainly includes: a first decoding unit 10 configured to decode soft information of a physical downlink control channel to obtain a first The decoding result and the attribute information of the physical downlink control information; the second decoding unit 20 is connected to the first decoding unit 10, and configured to decode the soft information according to the attribute information of the physical downlink control information, to obtain the second decoding. As a result, the comparing unit 30 is connected to the second decoding unit 20, and is configured to compare the first decoding result with the second decoding result. The determining unit 40 is connected to the comparing unit 30, and is configured to determine in the comparing unit 30. When a decoding result is consistent with the second decoding result, it is determined that the first decoder 10 successfully decodes the soft information. Wherein, the first decoding unit 10 and the second decoding unit 20 can be implemented by two different decoders. In a preferred embodiment of the present invention, the first decoding unit 10 is configured to perform full blind detection on the soft information of the PDCCH to obtain the first decoding result and the attribute information of the physical downlink control information. In another preferred embodiment of the embodiment of the present invention, the determining unit 40 is further configured to determine, by the comparing unit 30, that the first decoding result is inconsistent with the second decoding result, determining the first decoding unit 10 to soft information. A misdetection occurred during decoding. In still another preferred embodiment of the present invention, the attribute information includes but is not limited to: a location where the physical downlink control information is detected, and a length of the physical downlink control information. In another preferred embodiment of the embodiment of the present invention, the foregoing attribute information may further include: a CCE aggregation degree. Through the foregoing apparatus provided by the embodiment of the present invention, the first decoding unit 10 and the second decoding unit 20 use the first decoding unit 10 and the second decoding unit 20 to decode the soft information twice, and compare the two decoding results, so that the false detection rate is ideal. It can reach 1/2 ³² , which greatly improves the accuracy of blind detection of the physical downlink control channel (UE PDCCH) of the user equipment and the system performance of the user equipment (UE). From the above description, it can be seen that in the embodiment of the present invention, different decoders are used for decoding twice, and the two decoding results are compared, so that the false detection rate is reduced, and the data calculation is not increased. The occupied time further improves the accuracy of the physical downlink control channel (PDCCH) decoding and the system performance of the user equipment. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A decoding method comprising:

The first decoder decodes the soft information of the physical downlink control channel, and obtains the first decoding result and the attribute information of the physical downlink control information;

The second decoder decodes the soft information according to the attribute information of the physical downlink control information, to obtain a second decoding result;

Comparing the first decoding result with the second decoding result, and determining, in a case where the first decoding result is consistent with the second decoding result, determining the first decoder pair The soft information is successfully decoded.

The method according to claim 1, wherein the attribute information comprises: a location at which the physical downlink control information is detected, and a length of the physical downlink control information.

The method according to claim 2, wherein the attribute information further comprises: a control channel particle CCE aggregation degree.

The method according to claim 1, wherein the first decoder decodes the soft information of the physical downlink control channel, and obtains the first decoding result and the attribute information of the physical downlink control information, including: The first decoder performs full blind detection on the soft information to obtain attribute information of the first decoding result and the physical downlink control information.

The method according to any one of claims 1 to 4, wherein the method further comprises: determining, in a case where the first decoding result is inconsistent with the second decoding result, A decoder performs a false check when decoding the soft information.

6. A decoding device comprising:

The first decoding unit is configured to decode the soft information of the physical downlink control channel, to obtain attribute information of the first decoding result and the physical downlink control information;

a second decoding unit, configured to decode the soft information according to the attribute information of the physical downlink control information, to obtain a second decoding result;

a comparing unit, configured to compare the first decoding result with the second decoding result; a determining unit, configured to determine that the first decoder successfully decodes the soft information if the comparing unit determines that the first decoding result is consistent with the second decoding result. The apparatus according to claim 6, wherein the first decoding unit is configured to perform full blind detection on the soft information to obtain attribute information of the first decoding result and the physical downlink control information. The apparatus according to claim 6, wherein the determining unit is further configured to determine the first translation if the comparing unit determines that the first decoding result is inconsistent with the second decoding result The code unit misdetects when the soft information is decoded. The device according to any one of claims 6 to 8, wherein the attribute information comprises: a location at which the physical downlink control information is detected, and a length of the physical downlink control information. The apparatus according to claim 9, wherein the attribute information further comprises: a control channel particle CCE aggregation degree.