WO2003069819A1

WO2003069819A1 - Method and apparatus for decoding transport format combination indicator data

Info

Publication number: WO2003069819A1
Application number: PCT/CN2003/000058
Authority: WO
Inventors: Huabin Liu
Original assignee: Huawei Technologies Co. Ltd
Priority date: 2002-02-04
Filing date: 2003-01-23
Publication date: 2003-08-21
Also published as: AU2003211811A1; CN1437342A; CN1181633C

Abstract

The present invention discloses a method for decoding transport format combination indicator data. The method obtains a decimal value of TFCI that actual may be sent by searching the TFCS table which was disposed to physical layer by network layer, and expands a received information sequence ν=(ν0’, ν1’, ..νm-1) experienced the demodulation by the wireless channel which is TFCI encoded, sent from a RAKE receiver to an information sequence u=(u0,u1, …u2k-1), further obtains a result H=(h0,h1,...h2k-1) by performing a 2k step fast hadamard transform , and then narrows the hunting zone, which only searching the hadamard transform values with TFCI suffix for the maximum, and regards suffix t; of the maximum obtained as the result of the decimal TFCI value; adopting the above-mentioned scheme makes it need not to go on in possible ranges of all theories when searching for the maximum ,and narrows the range of TFCI decoding , thus changes the distribute of the weight of TFCI codeword, and may increase minimum distances of the TFCI codeword, thereby reduces the operation amount of the decoding, and optimizes the performance of decoding at the same time.

Description

Method and device for decoding transmission format combination indication data

The present invention relates to a decoding method and device in a code division multiple access (CDMA) mobile communication system, and particularly to a decoding method for transmission format combination indicator (TFCI) data in a CDMA system and a device for implementing the method.

Background technique

TFCI indicates the transmission format combination of multiple transmission channels. The transmission format includes information such as the transmission rate, CRC length, and encoding type. Therefore, the correctness of TFCI decoding is a prerequisite for the correct decoding of business data such as voice and data. In order to improve the correctness of TFCI transmission, in the 3rd Generation Mobile Communication Cooperative Organization (3GPP), on the data transmitting end, on the one hand, a linear block code (reed-leg ler) with better performance is used for encoding, and the other The aspect also increases the anti-interference ability by increasing the transmission power (relative to the dedicated physical data channel DPDCH, the transmission power is 0-6dB higher); at the receiving end, the TFCI bit error rate is reduced by selecting a better linear block code decoding method. The traditional and more popular TFCI decoding method can refer to the document "Optimal sof t Deci son Block Decoders Based on Fast Hadamard Transform" YAIR BEERY., IEEE Trans on Information Theory, 1986, May. P355-P365) on page 355-365 of this document defines the maximum release function for TFCI decoding, which is described as:

( ₁₎

Where s is the binary sequence of TFCI information to be encoded

_Si e {0, l}, when the sequence is converted to decimal, the leftmost side of the sequence is the low-order bit, and the right-hand side is the high-order bit. v = ( _VQ , _Vl , ... v _M — 0 is the received information sequence, this sequence contains the noise caused by the wireless channel, which belongs to all real numbers. k is the length of the binary representation sequence of TFCI, is The system pre-defined, it determines the maximum number of different TFCI values that the physical layer can transmit is ^2f . M is the codeword length (number of binary bits) after TFCI encoding. M is also pre-defined by the system and is determined by the system The encoding method used is determined. For example, if the system's TFCI encoding method uses the first order belly (16, 5) linear block code encoding of the split mode, that is, k = 5, m = 16, the physical layer can transmit up to ²⁵ = 32 different TFCI value, and the codeword length after TFCI encoding is 16. Another example is if the system's TFCI encoding method uses the normal mode second-order RM subcode (32, 10) linear block code encoding, that is, k = 10, m = 32, then The physical layer can transmit a maximum of 2 ^1Q = 1024 different TFCI values, and the codeword length after TFCI encoding is 32. It is the vector of the i-th column of the linear block code encoding matrix.

The decoding method directly based on formula (1) is theoretically feasible, but when k is large, the operation when decoding is implemented is very complicated, and an equivalent decoding method that reduces the amount of calculation is usually used: based on fast Hada Decoding method of Fast Hadamard Transform.

The decoding method based on fast Hada code transformation can be summarized as the following steps:

Step 1: After receiving the TFCI code sent by the RAKE receiver and demodulating the information sequence "^., ...-) of the wireless channel, expand the information sequence M = (Uo, Ui,...) According to the following formula (2). .U ₂ k- \) ∑ Vi Aj empty set

U ^{j = {} 0 4 '= empty set (2)

Where. = { _: 0 (^.) =}, Y = 0, l, 2 ... 2 ^A -l (3) In the above formula (3), 6 (^ ·) means to convert the binary column vector into a Decimal value. 4 is a set of subscripts of some column vectors calculated according to formula (3) in the coding matrix. The only thing these column vectors must satisfy is that it is exactly equal to j when it is converted to a decimal number

Step 2: Pair ¾ = 0. , "1, .. -1) Perform ^ -order fast Hada code transformation to get the result

hi two max hj, 0 <i≤2 ^k -l Step 3: The maximum value in the search, that is o≤J≤2M; Step 4: Get the index i of the maximum value obtained in Step 3 is the decimal decoding The resulting TFCI value. The disadvantage of the existing method is that the maximum value search in step 3 is to search for the maximum value among all possible ^{2 / f} values. Due to the large search range, the time and resources required for implementation are also relatively small. There are many TFCI values sent in the actual system, which are not all theoretically possible values, and they are often only a small part. Existing TFCI data decoding methods are not based on this fact, resulting in low decoding efficiency. Summary of the Invention

An object of the present invention is to provide a decoding method for a transmission format combination instruction data with higher decoding efficiency and a device for implementing the method. To achieve the above object, the method for decoding the transmission format combination indication data provided by the present invention includes: (1) The transmission format combination indication (TFCI) decoding device searches from a transmission format combination set (TFCS) table configured to the physical layer by the network layer to obtain a decimal TFCI value that may actually be sent, and uses the symbol as ^ ti , ... J _n _i, where "is the number of TFCs in the TFCS table;

(2) After the TFCI decoding device receives the TFCI-encoded information sequence 2 demodulated by the wireless channel from the RAKE receiver, and then ^, ^, ... ^ ^, it expands to obtain the information sequence according to the following formula " ⁼ (" Q, "1, ·." 2-1):

∑ vt Aj ≠ empty set

U ^{j = {} 0 = empty set

Where 4 =

, l, 2 ... 2 ^k -l, means to convert a binary column vector into a decimal value;.

(3) Determine whether there is a mask in the TFCI encoding. If it exists, perform a demasking process on the information sequence u = (u ₀ , u .. "2-1), and then perform step (4), otherwise, do not perform the demasking. Code processing, and directly execute step (4);

(4) Perform a 2 ^A fast Hada code transformation on the information sequence = ( ₀ , Μι, .Μ ₂ ^) to get the result = (/ '., /",...½-1);

(5) Narrow the search range, and search only the Hada code transformation values subscripted as TFCI.

₇ h — max h _tj , <j <n- \ large value, let the subscript be the maximum transformation value, that is, <¾ · ≤ "-ι;

(6) Obtain the subscript of the maximum value obtained in step 5 as the TFCI value of the decimal decoding result.

The decoding device for the transmission format combination indication data provided by the present invention includes a TFCI searcher, a bit shift truncation processor, a position translator, a demask selection switch, and a mask processing unit. Processor, Hada code converter, maximum value searcher and comparison judger, wherein:

A TFCI searcher, configured to search from a TFCS table configured by the network layer to the physical layer, and obtain a decimal TFCI value that may actually be sent;

A bit shift truncation processor is used to receive the decimal TFCI value sent by the TFCI searcher, and decide whether to pre-process the extraction mask of TFCI according to the current TFCI encoding situation. The mask is used when TFCI encoding, Extract the mask from the TFCI value and send it to the mask processor to remove the mask; it is also used to extract the symbol control information from the TFCI value and send it to the maximum value searcher to adjust the sign of the Hada code transformation value;

A position switcher is used to demodulate the TFCI information sequence ^ν = ( ^ν ， ^νι , ... ^ν 『ι) after demodulation of the RAKE receiver to obtain the information sequence" = 0 "according to the following formula, _Ml , ^..w _2M );

∑ v _t Aj ≠ empty set

U ^{j = (} empty set

Formula _{4 = {:) =},} j = 0, l, 2 ... 2 ^ -l, shows a binary column vector into a decimal value;

A demasking selection switch is used to judge whether the information sequence ^^^^^, ^^ — ^ needs to be demasked according to the TFCI encoding mode, and if necessary, the information sequence u = (u ₀ , u .. ₂ ' _£ — 1) is sent to the mask processor, otherwise the information sequence is directly sent to the Hada code converter;

A mask processor for demasking an information sequence that needs to be demasked using a mask sent by a bit shift truncation processor "= (" Q, "1, .." 2), Then send the masked information sequence "= (" o, "i, 1) to the Hada code converter;

Hada code converter, used for ^ -order fast ha for the information sequence "= (" 0 ^ 1, .. "2-1) Result obtained by the code conversion ^^ (^… ^ a); a maximum value searcher, which is used to transform the output of the code of the hard code converter

H ^ / ^ / ^ J ^) search for the maximum value in the Hada code transform value of the subscript TFCI, and send the search result to the comparison decider, and decide to output the TFCI value of the decimal decoding result. Since the present invention obtains the actually possible TFCI value sent from the network layer, it makes full use of

The information in the TFCS table makes searching for the maximum value not necessary in all theoretically possible ranges. It only needs to be performed in the Hada code transformation value of the n TFCI values that may be actually sent, reducing the scope of TFCI decoding. As a result, the weight distribution of the TFCI codeword is changed, and the minimum code distance of the TFCI codeword may be increased, thereby reducing the amount of decoding operations and optimizing the decoding performance. Therefore, the present invention is more efficient for TFCI decoding . BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart of an embodiment of the method of the present invention; FIG. 2 is a flowchart of TFCI decoding in a normal mode by applying the present invention; and FIG. 3 is a block diagram of an embodiment of the apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in further detail below with reference to the drawings and embodiments. It can be known from the existing decoding method of TFC I that the maximum likelihood decoding of the existing method is — 1

Find one of all possible ^2A pieces of information s that makes the formula ^^) ⁼ S ( ^-1 ) ^^ 'the calculated value is the largest', and search for the maximum value from all the ²⁰ values, so as to recover from the maximum value Out S, realize decoding. Because the maximum value is searched among all possible ² values, and the TFCI value sent by the actual system is not all theoretically 2 possible values, it is often only a small part. For example, there are two or six. The few possible TFCI values actually sent can be obtained from the information configured by the network layer to the physical layer. The present invention will use this information to simplify the calculation amount and optimize the performance. .

FIG. 1 is a flowchart of an embodiment of a method according to the present invention. According to Figure 1,

First, in step 1, the TFCI decoding device searches and extracts the TFCI value that can be actually sent from the TFCS table configured by the network layer to the physical layer, and uses the symbol to, t _x , .... t _n- , Where w is the number of TFCs in the TFCS table. It is also the number of TFCI values that may actually be sent. This step is a critical step. Because this step reduces the scope of TFCI decoding, and thus changes the TFCI codeword weighting division, it may also increase the minimum code distance of the TFCI codeword, resulting in a final reduction in the amount of decoding operations. At the same time, the decoding performance is optimized.

In step 2, after the TFCI decoding device receives the TFCI code sent from the RAKE receiver and demodulates the information sequence two (^, ¹¹ , "" 1) of the wireless channel, it expands to obtain the information according to the following formula (2) Sequence ^{M =} (Q, Ul, ..U ₂ kl)

∑ vi Aj Φ empty set

^{Uj = x} 0 ^ = empty set (2)

Where = {z ': bfe)'} '= 0, l, 2 ... 2 ^{/ / c} -l, which translates a binary column vector into a decimal value. That is, 'is a set of subscripts of some column vectors calculated according to formula (3) in the coding matrix. The condition that these column vectors must meet is that when it is converted to a decimal number, it is exactly equal to j. The purpose of this step to expand the information sequence ^^^, ^, ...-is to establish an internal relationship between formula (1) and the fast Hada code transformation, so that the extended information sequence M = 0 _G can be directly used in the next step. " i, .. W2M) for fast Hada code transformation. In step 3, it is determined whether there is a mask in the TFCI encoding. If it exists, in step 4 the information sequence " ⁼ (" Q, "i, .." ² ) is demasked, and then step 5 is performed, otherwise it is directly performed. Step 5: ^ order fast Hada code transformation is performed on the information sequence u = (uo, u 2) to obtain the results i ^ d /, ... ½—). The above 2 ^{/ f} transformation results correspond to the formula (1), which is a result obtained by traversing 2 ^{/ £} possible TFCI binary to-be-encoded information sequences. 'Because the received information sequence is expanded in step 2, the result obtained by performing a fast Hada code transformation on the expanded information in this step corresponds to the result obtained by traversing all ^ possible s calculations in formula (1). Therefore, compared with the direct use of formula (1), the calculation in this step can greatly reduce the amount of calculation and is easy to implement.

Step 6. Narrow the search range and search only in the Hada code transform value subscripted as TFCI

_T = max h _t!, 0 <j≤n- l maximum value, suppose the transformation value of subscript ^ is the largest, that is, Q≤≤ "-1.

Step 6 is another key step of the present invention. Since step 1 has already obtained the actual possible TFCI value sent from the network layer, the search for the maximum value in this step does not need to be performed in all theoretically possible ranges, only the subscript is actually possible Search for the maximum value in the Hada code transform value of the sent n TFCI values. This step is closely combined with step 1 to reduce the scope of TFCI decoding, so that the TFCI codeword weight distribution can be changed, and the minimum code distance of the TFCI codeword may be increased, resulting in a reduction in the amount of decoding operations and optimization of decoding performance. . In step 7, the index of the maximum value obtained in step 6 is the TFCI value of the decimal decoding result. This is because the processing of step 2 implies a fact: if the TFCI binary sequence to be encoded information s = (s.,, ..., -i), ^ -6 {0,1}, converted to decimal The number is then M calculated according to formula (1) is exactly equal to /. So if it is the maximum value, the subscript ^ is the decimal value of the decoded result TFCI. In the following, two encoding methods of TFCI in 3GPP are used: first-order RM (16, 5) linear block code coding in split mode and second-order M code subcode (32, 10) linear block code coding in normal mode. The decoding method is further explained.

Refer to Figure 2 for the decoding implementation method of the second-order RM code subcode (32, 10) TFCI code in normal mode. Because (32, 10) TFCI encoding adds a mask, it needs to be unmasked and then combined with the present invention to perform TFCI decoding.

First, in step 11, search TFCI set to give 10 decimal in the TFCS, referred to as _{a, t x, ... J "-i} , which" is the number of TFCS a TFC table. Then in step 12, use c ₀ , c _l5 ... c „-1 to record the mask obtained by shifting the TFCI right by 6 bits. At this time, the mask set obtained may be duplicated. Delete the duplicated mask to obtain a valid mask. Code set, re-recorded as CQ,

Where is the number of valid masks. In step 13, the 32 received TFCI data to be decoded are buffered and transformed into the normal order. The original 30th data is transferred to the current 0th data, the original 31st data is transferred to the current 16th data, and the original 0-14 These data are adjusted to the current 1-15 data, and the original 15-29 data are adjusted to the current 17-31 data, denoted as ^ 2 ^. ,, ...). At step 14, an initial value is assigned to the global maximum value variable max_value of the Hada code transformation value, and an initial value ^ ^ 0 is assigned to the mask counter. In step 15, the 32 TFCI data to be decoded are demasked and subjected to a 32-level Hada code transformation, and 32 transformation values are recorded, which are denoted as Ao, hj ₃₁ . In step 16, the lower 5 bits of the TFCI are intercepted (& 31J = 0,1,… "-1) to obtain the index of the transform value that needs to participate in the comparison decision under the current mask, and count according to the 5th bit (counting from the 0th bit) 1) adjusts the sign of the transformation value. If the 5th bit is 1, the transformation value is adjusted to the opposite number. If the 5th bit is 0, the adjustment is not performed. Then only the subscript is (& 31, = 0, l, J -1) Search for the maximum value of the adjusted Hada code transformation value of the symbol, for example, the transformation value of the subscript (& ³ 1), · & Μ)

& 3 Update the global maximum value max— va 1 ue and update and save the corresponding index.

In step 17, it is judged whether the mask set has been traversed. If not, the mask counter is incremented by 1, that is, steps 15 and 16 are repeated; if it has been traversed, the decoded TFCI value of step 18 is output, that is, the step after the last demasking process. The subscript of the maximum of the Harda code of 16.

The decoding method of the present invention corresponding to the first-order (16, 5) TFCI encoding of the split mode, first searches for the TFCI set in base 10 from the TFCS, and records it as ti,…! Where "" is the number of TFCs in the TFCS table. Step 2 will receive the TFCI-encoded information sequence through the wireless channel.

Adjust the order, put the last data first, that is, the original 15th data V15 is adjusted to the current 0th data ν. , 0 to 14 of the original data is now adjusted VQ~vu Γ15 data of vi ~ v _15. Since the last column of the encoding matrix is all 1, we can reduce the order pair in step 3.

Perform the 16th-order fast Hada code transformation to get the result Η = (, ... ^. In step 4, intercept the lower 4 bits of TFCI (& 15, = 0,1, ... "-1) to obtain the transformation that needs to participate in the comparison decision Value subscript, and the highest bit of TFC I, which is the 4th bit (counting from 0th bit), adjusts the sign of the transformation value. If the 4th bit is 1, the transformation value is adjusted to the opposite number. If the 4th If the bit is 0, it will not be adjusted, and the transformed value after adjusting the sign will still be represented by ... ^ ⁵ ). In step 5, the search range is narrowed down, and only the Hada code with the subscript (& 15, = 0,1, — "-1) Search for the maximum value in the transformation value (adjusted sign), and set the transformation value h ₅ with the subscript () to the maximum value, that is, 0 <j≤nl

. Finally, the subscript of the maximum value obtained in step 6 in step 6 is the TFCI value of the decimal decoding result. Fig. 3 is a block diagram of an embodiment of the device according to the present invention. The decoding device for the transmission format combination indication data shown in FIG. 3 includes a module 103 for demodulating the TFCI information sequence of the RAKE receiver, and a TFCI searcher 101, a bit shift truncation processor 102, a position switch 104, and a demasking. The code selection switch 105, the mask processor 106, the Hada code converter 107, the maximum value searcher 108, and the comparison decision device 109, wherein:

The TFCI searcher 101 is configured to search from a TFCS table configured by the network layer to the physical layer, and obtain a decimal TFCI value that may actually be sent, and the value is sent to the bit-shift interception processor 102, according to the current TFCI The encoding situation determines whether to pre-process the TFCI extraction mask. When the TFCI encoding is used, the mask is extracted from the TFCI value and sent to the mask processor 106 to remove the mask. Bit shift truncation processing The processor 102 also extracts symbol control information from the TFCI value and sends it to the maximum value searcher 108 to adjust the sign of the Hada code transformation value;

A module 103 for demodulating the TFCI information sequence of a RAKE receiver, for receiving Ding from a wireless channel? ^ Encode the demodulated information sequence ¹ ^ ^ ¹ , ^...- !) Of the wireless channel, and send the sequence to the position translator 104, and the position translator 104 sends the information sequence ^{ν =} ( ^ν ， ^νι , ... · ^Ν «_ι) is expanded according to the following formula to obtain the information sequence" = ("., ^, .. 1 ^ —0:

∑ Vi Aj Φ empty set

^{Uj = {} 0 = in the empty set ^ = {6 (^) =} 'y = 0, l, 2 ... 2 ^A -l, which means that the binary column vector is converted into a decimal value;

The demasking selection switch 105 is used to judge whether the information sequence "= (" Q, "1, 2M) needs to be demasked according to the TFCI encoding mode, and if necessary, the information received from the position changer 104 The sequence M = ("Ο," Ι,. · Μ2Μ) is sent to the mask processor 106, The mask processor 106 uses the mask sent by the bit shift truncation processor to demask the information sequence that needs to be masked "= (MG," 1, 2), and then removes the masked The information sequence "= (" 0, "1, ·· M2) is sent to the Hada code converter 107; otherwise, the information sequence is directly sent to the Hada code converter 107. The Hada code converter 107 pairs the information sequence" ^ (^, ^, ^^ — ^ perform a ^ -order fast Hada code transformation to obtain the result ^ /, ^, ... /? ^), And the result is sent to the maximum value searcher 108, and the maximum value searcher 108 transforms the output of the Hada code converter Result = (i,) searches for the maximum value in the Hada code transform value of the subscript TFCI, sends the search result to the comparison judger, and judges and outputs the TFCI value of the decimal decoding result.

Claims

Rights request

1. A decoding method for transmission format combination indication data, including:

(1) The transmission format combination indication (TFCI) decoding device searches from a transmission format combination set (TFCS) table configured to the physical layer by the network layer, and obtains a decimal TFCI value that may actually be sent. ... J „-i, where" is the number of TFCs in the TFCS table;

(2) After receiving the TFCI code sent by the RAKE receiver, the TFCI decoding device demodulates the information sequence II of the wireless channel, ^, ...-and then expands to obtain the information sequence according to the following formula "= (Uo, U : U ₂ kl):

∑ Vi Aj ≠ empty set

U ^{j = {} o = empty set

Where

Represents a binary column vector into a decimal value;

(3) Determine whether there is a mask in the TFCI encoding, and if it exists, the information sequence

Then step (4) is performed, otherwise no demasking processing is performed, and step 4 is directly performed;

(4) The result is obtained by performing a second-order fast Hada code transformation on the information sequence "= OQ, WI, .. M ₂ );

_T h _ti = max h _ti , a large value of 0≤j≤nl, and set the transformation value of the subscript ^ max, that is, 0≤ · ≤ «-1; (6) obtain the subscript of the maximum value obtained in step 05 as Decoded TFCI value in decimal. 2. A decoding device for transmission format combination instruction data, including a TFCI searcher, a bit shift truncation processor, a position translator, a demask selection switch, a mask processor, a Hada code converter, and a maximum search And a comparison decider, wherein:

A bit shift truncation processor is used to receive the decimal TFCI value sent by the TFCI searcher, and decide whether to pre-process the extraction mask of TFCI according to the current TFCI encoding situation. When TFCI encoding is used, Extract the mask from the TFCI value and send it to the mask processor to remove the mask; it is also used to extract the symbol control information from the TFCI value and send it to the maximum value searcher to adjust the sign of the Hada code transformation value;

A position switcher is used to demodulate the TFCI information sequence ^{ν = (} ， ^νι , ... ^ν 『1） after the RAKE receiver is demodulated to obtain the information sequence“ 二 ^., ”..” —) :

∑ v _t Aj Φ empty set

^{Uj = {} 0 4 = empty set

In the formula, 4 = { _Z ':'; = 0,1,2 ... 2 ^ -1, which means that the binary column vector is converted into a decimal value, and the order of the data streams is appropriately switched according to the characteristics of the encoding matrix;

Demasking selection switch, used to judge whether the information sequence is required according to the TFCI encoding mode "= (" 0, ^, .. 2 ^ · — perform demasking processing, and if necessary, the information sequence

U = {Uo, U 2M) is sent to the mask processor, otherwise the information sequence is directly sent to the Hada code converter;

Mask processor, which is used to use the mask pair sent by the bit-shift truncation processor. De-masking information sequence "= θθ, Μΐ, perform de-masking processing, and then send the de-masking information sequence" = ("Q," 1, 2) to the Hada code converter;

Hada code converter, used to perform ² fast Hada code transformations on the information sequence "= (" 0, "1, j _2M ) = (ho, hj _2M );

Maximum value searcher, used for transforming the output of Hada code converter

H ^ / ^ / ^ JsM), the maximum value is searched in the Hada code transform value of TFCI, and the search result is sent to the comparison judger, and the TFCI value of the decimal decoding result is output.