1、m 3404583 0071550 TOT m ETSI/TC SMG Released by : ETSI/PT 12 Release date: February 1992 RELEASE NOTE Recommendation GSM 05.03 Channel Coding Previously distributed version : 3.5.1 (Release 3/90) New Release version February 92 : 3.5.1 (Release 92, Phase 1) 1. Reason for chancres No changes since th
2、e previously distributed version. 4 m 3404583 0073553 946 m ETSI/GSM GSM REC. 05.03/1 version 3.5.1 GSM Recommendation: 05.03 Title: CHANNEL CODING Release Date: February, 1992 CONTENTS : 1. 2. 2.1 2.2 3. 3.1 3.2 3.3 3.4 3.5 3.6 3.7 4. 4.1 4.2 4.3 4.4 4.5 4.6 4.7 SCOPE GENERAL General Organization N
3、aming Convention TRAFFIC CHANNELS (TCH) Speech channel at full rate (TCH/FS) Speech channel at half rate (TCH/HS) (tba) Data channel at full rate, 9.6 kbit/s services (TCH/F9.6) Data channel at full rate, 4.8 kbit/s services (TCH/F4.8) Data channel at half rate, 4.8 kbit/s services (TCH/H4.8) Data c
4、hannel at full rate, I2.4 kbit/s services (TCH/F2.4) Data channel at half rate, 5 2.4 kbit/s services (TCH/H2.4) CONTROL CHANNELS Slow associated control channel (SACCH) Fast associated control channel (FACCH) Broadcast, paging and access grant channels (BCCH, PCH and AGCH) Stand-alone dedicated con
5、trol channel (SDCCH) Random access channel (RACH) Synchronization channel (SCH) Handover Access Burst ANNEXES: 1. Summary of channel types 2. Summary of polynomials for convolutional codes 3. Examples (to be added) Number of pages: 22 Note: (tba) indicates a section to be added later. W 3404583 0073
6、552 882 1. ETSI/GSM GSM REC. 05.03/2 version 3.5.1 Recommendation 05.03 CHANNEL CODING SCOPE : A reference configuration of the transmission chain is shown in Rec.05.01. According to this reference configuration, this recommendation specifies the data blocks given to the encryption unit. It includes
7、 the specification of encoding, reordering, interleaving and the stealing flag. It does not specify the channel decoding method. The definition is given for each kind of logical channel, starting from the data provided to the channel encoder by the speech coder, the data terminal equipment, or the c
8、ontroller of the MS or BS. The definitions of the logical channel types used in this recornendation are given in Rec.05.02, a summary is in annex i. 2. GENERAL 2.1 GENERAL ORGANIZATION: Each channel has its own coding and interleaving scheme. However, the channel coding and interleaving is organized
9、 in order to have as much as possible a unified decoder structure. Each channel uses, in this order, the following sequence of operations: - The information bits are coded with a systematic block code, building words of information + parity bits. - These information + parity bits are encoded with a
10、convolutional code, building the coded bits. - Reordering and interleaving the coded bits, and adding a stealing flag, gives the interleaved bits. All those operations are made block by block, the size of which depends on the channel. However, most of the channels use at one point a comon structure
11、which is a block of 456 coded bits, interleaved and mapped onto bursts in a very similar way for all of them. Figure 1 gives a diagram showing the general structure of the channel coding. This block of 456 coded bits is the basic structure of the channel coding scheme. In the case of speech TCH, thi
12、s block carries the information of one speech frame. In case of control channels, it carries one message. W 3YOY583 O073553 739 W class 1 cyclic code FIRE code cyclic code +tail +tail +tail in : 260 bits in : 184 bits in : PO bits out : 267 bits out : 228 bits out : P1 bits 3.1.1 4.n.l 4.5/4.6 ETSI/
13、GSM GSM REC. 05.03/3 version 3.5.1 cyclic code +tail in : NO bits out : N1 bits 3 .n.2 in : 228 bits out : 456 bits 4.11.3 convolutional code K=5, 2 classes 3.1.2 in : P1 bits out : 2*P1 bits 4.5/4.6 3 7- - I I - reordering and partitioning + stealing flag in : 456 bits out : 8 sub-blocks convolutio
14、nal code K=5, rate r in : N1 bits out : 456 bits 3.n.3 I I block diagonal interleaving out : pairs of sub-blocks 3.1.3.b in : 8 sub-blocks 1-1- block rectangular interleaving out : pairs of sub-blocks 4.1.4.b in : 8 sub-blocks diagonal interleaving + stealing flags out sub-blocks intra-burst interle
15、aving in : pairs of sub-blocks out : pairs of sub-blocks 3.1.3.c I 1 Encryption Unit 4 I Figure 1: CHANNEL CODING AND INTERLEAVING ORGANIZATION In the case of DATA TCHS. NO, N1. n depends on the type of data TCH. In each box, the last line indicates the chapter defining the function. interface 1 : I
16、nformation bits (d) 3 : coded bits (c) 2 : Information + parity bits (u) 4 : interleaved bits (e) 3404583 00711554 655 2.2 ETSI/GSM GSM REC. 05.03/4 version 3.5.1 In the case of fast ACCH, such a block is stolen from the TCH, used for an ACCH message, and is inserted in the TCH interleaving structur
17、e. Each block of 456 coded bits has in addition a stealing flag (8 bits), indicating if the block belongs to the TCH or to the fast ACCH. In case of slow ACCH, BCCH or CCCH, this stealing flag is dummy. Some cases do not fit in the general organization, and do not use the block of 456 coded bits. Th
18、ey are the random access messages of the RACH on uplink and the synchronization information broadcast on the SCH. Naming Convention For ease of understanding a naming convention for bits is given for use throughout the recommendation : - General naming “k“ and ,jn for numbering of bits in data block
19、s and bursts. “KxW gives the amount of bits in one block, where “x“ refers to the data type “nn is used for numbering of delivered data blocks where “Nn marks a certain data block .Bn is used for numbering of bursts or blocks where “BO“ marks the first burst or block carrying bits from the data bloc
20、k with n = O (first data block in the transmission) - Data delivered to the encoding unit (interface 1 in fig. 1) : d (n, k) or d (k) for k = 0,1, ., Kd-1 n = 0,1, ., N,N+1, - Data after the first encoding step (block code, cyclic code ; interface 2 in fig. 1) : u(n,k) or u (k) for k = 0,1, ., Q-1 n
21、 = 0, ,., N,N+1, . - Data after the second encoding step (convolutional code ; interface 3 in fig. 1) : c(n,k) or c(k) for k = 0,1, ., ,-l n = 0,1, ., N,N+1, 3404583 0073555 573 3 ETSI/GSM GSM REC. 05.03/5 version 3.5.1 - Interleaved data : i(B,k) for k = 0,l , ,Ki-l B = Bo, B0+1, - Bits in one burs
22、t (interface 4 in fig. 1) : e(B,k) for k = 0,1, ,114,115 B = BO, Bo + 1, TRAFFIC CHANNELS (TCH): Two kinds of traffic channels are considered: speech and data, Both of them use the same general structure (see fig.l), and in both cases, a piece of information can be stolen by the fast ACCH. 3-1 Speec
23、h channel at full rate (TCH/FS) : The speech coder delivers to the channel encoder a sequence of blocks of data. In case of a full rate speech TCH, one block of data corresponds to one speech frame. Each block contains 260 information bitstincluding 182 bits of class 1 (protected bits), and 78 bits
24、of class 2 (no protection), (see Tables 2 and 3) The bits delivered by the speech codec are labelled d(O), d(l), ., d(259), defined in the order of decreasing importance, as specified in 06.10. 3.1.1 Parity and tailing for a speech frame: a) Parity bits: The 50 first bits of class 1 are protected by
25、 three parity bits used for error detection. These parity bits are added to the 50 bits, according to a degenerate (shortened) cyclic code (53,50,2), using the generator polynomial: g(D) = D3 + D + 1 The encoding of the cyclic code is performed in a systematic form, which means that, in GF(2), the p
26、olynomial: d(0)D52 + d(l)D51 + + d(49)D3 + p(0)D2 + p(l)D+ p(2) where p(O), p(i), p(2) are the parity bits, when divided by g(D) , yields a remainder equal to 1 + D + D2 ETSIJGSM GSM REC. 05.03/6 version 3.5.1 b) Tailing bits and reordering: The information and parity bits of class 1 are reordered,
27、defining 189 information + parity + tail bits of class 1, u(O), u(i), . , (188) defined by: u(k) = d(2k) and (184-k) = d(2k+l) for k=0,1,. ,go u(91+k) = p(k) for k=0,1,2 (k) = O (tail bits) for k=185, 186, 187, 188 3.1.2 Convolutional encoder: The class 1 bits are encoded with the 1/2 rate convoluti
28、onal code defined by the polynomials: GO = 1 + D3+ D4 G1 = 1 + D + D3+ D4 The coded bits c(O), c(l), ., (455) are then defined by: - class 1 : c(2k) = u(k) + u(k-3) + u(k-4) (2k+l) = u(k) + u(k-1) + (k-3) + (k-4) for k=0,1,. . . . . ,188 and u(k)=O if kO - class 2 : c(378+k) = d(182+k) for k=O, 1, .
29、 . . . ,77 3.1.3 Interleaving The coded bits following rule i(B,j) = for k = are reordered and interleaved according to the n = 0,1, , N,N+1, B = Bo + 4. n + k mod (8) j = 2(49k) mod 571 + (k mod 8) div 41 The result of the interleaving is a distribution of the reordered 456 bits of a given data blo
30、ck, n=N, over 8 blocks using the even numbered bits of the first 4 blocks (B = Bo + 4N + 0,1,2,3) and odd numbered bits of the last 4 blocks (B = Bo + 4 N + 4,5,6,7). The reordered bits of the following data block, n = N+1, use the even numbered bits of the blocks B = Bo + 4 N + 4,5,6,7 and the odd
31、numbered bits of the blocks B= Bo + 4 (N+2) + 0,1,2,3. Continuing with the next data blocks shows that one block always carries 57 bit of data from one data blocks (n =N) and 57 bit of data from the next block (n = N+1), where the bits from the data block with the higher number always are the even n
32、umbered data bits, else the odd numbered. The block of coded data is interleaved “block diagonal“, where a new data block starts every 4th block and is distributed over 8 blocks. 3404583 0073557 3blt ETSI/GSM GSM REC. 05.03/7 version 3.5.1 3.1.4 Mapping on a Burst The mapping is given by the rule :
33、e(B,j) = i(B,j) and e(B, 59+j) = i(B,57 + j) for j = O, . 56 and e(B,57) = hl(B) and e(B,58) = hu(B) The two bits, labelled hl(B) and hu(B) on burst number B are flags used for indication of control channel signalling. - hl(B) = O and hu(B) = O indicates, that all bits in burst B belong to a traffic
34、 channel frame. - hu(B) = 1 indicates that all even numbered bits are used for signalling purposes. - hl(B) = 1 indicates that all odd numbered bits are used for signalling purposes. In a traffic channel these flags indicate stolen bits for signalling purposes (see section 4.2.5). 3.2 Speech channel
35、 at half rate (TCH/HS) : To be defined for a future evolution of the system. 3.3 Data channel at full rate, 9.6 kbit/s services: The definition of a 12.0 kbit/s data flow for data services is given in Recommendation 04.21. 3.3.1 Interface with user unit: The user unit delivers to the encoder a bit s
36、tream organized in blocks of 60 information bits (data frames) every 5 ms. Four such blocks are dealt with together in the coding process d(O), ., d(239). For non-transparent services those four blocks will align with one 240-bit RLP frame. 3 -3.2 Block code: The block of 4 * 60 information bits is
37、not encoded, but only increased with 4 tail bits equal to O at the end of the block. U (k) =d (k) u(k) =O k=O, . . . ,239 k=240, . . . ,243 m 3404543 0071,554 ZTO ETSI/GSM GSM REC. 05.03/8 version 3.5.1 3.3.3 Convolutional encoder : This block of 244 bits u(O), ., (243) is encoded with the punctured
38、 convolutional code of rate 1/2 defined by the following polynomials: GO = 1 + D3+ D4 G1 = 1 + D + D3+ D4 resulting in 488 coded bits C(O), C(l), ., C(487) with C(2k) = u(k)+ +U (k-3 ) +U (k-4) C(2k+l) = u(k) + (k-1) +u(k-3) +u(k-4) for k = O, . 243 ; u(k)=O,KO The code is punctured in such a way th
39、at the following 32 coded bits: (C(i1 + 15j); j = 0,31 are not transmitted. The result is a block of 456 coded bits, c(O), ., (455) 3.3.4 interleaving: The coded bits are reordered and interleaved according to the following rule : i(B,j) = c(n,k) for k = O, , 455 n = 0,1, ., N,N+1, B = Bo +4n + k mo
40、d (19) + k div 114 The result of the interleaving is a distribution of the reordered 114 bit of a given data block, n = N, over 19 blocks, 6 bits equally distributed in each block, in a diagonal way over consecutive blocks. The block of coded data is interleaved “diagonal“, where a new block of code
41、d data starts with every block and is distributed over 19 blocks. 3.3.5 Mapping on a Burst The mapping is done as specified for TCH/FS in section 3.1.4 On bitstealing by a FACCH, see section 4.2.5. m 3404583 0073559 L37 m ETSI/GSM GSM REC. 05.03/9 version 3.5.1 3.4 Data channel at full rate, 4.8 kbi
42、t/s services (TCH/F4.8): The definition of a 6.0 kbit/s data flow for data services is given in Reconmiendation 04.21. 3.4.1 Interface with user unit: The user unit delivers to the encoder a bit stream organized in blocks of 60 information bits (data frames) every 10 ms, d(O) , I d(59) I. 3.4.2 Bloc
43、k code: Sixteen bits equal to O are added to the 60 information bits, the result being a block of 76 bits, u(O), . . ., u(75), with: u(l9k+p) = d(l5k+p) for k = O,. . .,3 and p = O,. . .,14; u(l9k+p) = O for k = O ,., 3 and p = 15, ., 18. Two such blocks forming a block of 152 bits dealt with togeth
44、er in the rest of the coding process u (O), . . . ,u (151) I are u (k) = ul(k) , k=0,75 (u1 = 1:St block) u(k+76) = u2(k) , k=0,75 (u2 = 2:nd block) 3.4.3 Convolutional encoder: This block of 152 bits is encoded with the convolutional code of rate 1/3 defined by the following polynomials: G1=1+D +D3
45、+D4 G2 = 1 + D2 + D4 G3=1+D +D2+D3+D4 The result is a block of 3 * 152 = 456 coded bits, C(O) .c(455) 1, c (3k) = U (k)+u (k-l)+ U (k-3)+ (k-4) c(3k+l) = U (k)+ U (k-2) + U (k-4) c(3k+2) = U (k)+u (k-l)+u (k-2)+ (k-3)+ (k-4) for k = O, ., 151 ; u(k)=O, kO 3.4.4 interleaving: The interleaving is done
46、 as specified for the TCH/F.9.6 in section 3.3.4 3.4.5 Mapping on a Burst The mapping is done as specified for the TCH/FS in section 3.1.4. on bitstealing for signalling purposes by a FACCH, see section 4.2.5. ETSI/GSM GSM REC. 05.03/10 version 3.5.1 3.5 Data channel at half rate, 4.8 kbit/s service
47、s (TCH/H4.8) : The definition of a 6.0 kbit/s data flow for data services is given in Recommendation 04.21. 3.5.1 Interface with user unit: The user unit delivers to the encoder a bit stream organized in blocks of 60 information bits (data frames) every 10 ms. Four such blocks are dealt with togethe
48、r in the coding process d(O), . . .,d(239) 1. For non transparent services those four blocks shall align with one complete 240-bit RLP frame. 3.5.2 Block code: The block encoding is done as specified for the TCH/F9.6 in section 3.3.2. 3.5.3 Convolutional encoder: The convolutional encoding is done a
49、s specified for the TCH/F9.6 in section 3.3.3. 3.5.4 interleaving: The interleaving is done as specified for the TCH/F9.6 in section 3.3.4. 3.5.5 Mapping on a Burst The mapping is done as specified for the TCH/FS in section 3.1.4. On bitstealing for signalling purposes by a FACCH, see section 4.2.5. 3.6 Data channel at full rate, 2.4 kbit/s and less services (TCH/F2.4) : The definition of a 3.6 kbit/s data flow for data services is given in Recommendation 04.21. 3.6.1 Interface with user unit: 4 The user unit delivers to the e
