Method and apparatus for convolutional coding to support multiplexing in a wideband communications system
An approach for encoding a physical layer (PL) header of a PL data frame is provided. The PL header comprises sixteen information bits u i , (i=0, 1, 2, . . . , 15), and the encoding is based on a convolutional code, whereby, for each information bit, five associated parity bits p i,k , (k=0, 1, 2, 3, 4) are generated, resulting in 80 codebits. The resulting 80 codebits are punctured to form a (16,77) codeword (c 0 , c 1 , c 2 , . . . , c 76 ). The codebits of the (16,77) codeword are repeated to generate a (16,154) physical layer signaling codeword (c 0 , c 0 , c 1 , c 1 , c 2 , c 2 , . . . , c 76 , c 76 ) for transmission of the PL data frame over a channel of a communications network. Further, for each information bit, each of the associated five parity bits is generated based on a parity bit generator, as follows: p i,k =(u i *g k,0 )⊕(S 0 *g k,1 )⊕(S 1 *g k,2 )⊕(S 2 *g k,3 )⊕(S 3 *g k,4 ), where S 0 =u i-1 , S 1 =u i-2 , S 2 =u i-3 , S 3 =u i-4 , and wherein generator polynomials for g k =(g k,0 , g k,1 , g k,2 , g k,3 , g k,4 ), are as follows: g 0 =(1, 0, 1, 0, 1); g 1 =(1, 0, 1, 1, 1); g 2 =(1, 1, 0, 1, 1); g 3 =(1, 1, 1, 1, 1); g 4 =(1, 1, 0, 0, 1).
1. A method comprising:
encoding, by a processor of a device, a physical layer header of a physical layer data frame, wherein the physical layer header comprises sixteen information bits u i , i=0, 1, 2, . . . , 15, and the encoding is based on a rate 1/5 convolutional code, wherein, for each information bit u i , i=0, 1, 2, . . . , 15, five associated parity bits p i,k , k=0, 1, 2, 3, 4 are generated, resulting in a first codeword of 80 codebits; and
repeating the codebits of the first codeword to generate a physical layer signaling codeword for transmission of the physical layer data frame over a channel of a communications network;
wherein, for each information bit u i , i=0, 1, 2, . . . , 15, each of the associated five parity bits p i,k , k=0, 1, 2, 3, 4 is generated based on a parity bit generator, as follows:
p i,k =( u i *g k,0 )⊕( S 0 *g k,1 )⊕( S 1 *g k,2 )⊕( S 2 *g k,3 )⊕( S 3 *g k,4 ),
where S 0 =u i-1 , S 1 =u i-2 , S 2 =u i-3 , S 3 =u i-4 , and
wherein generator polynomials for g k =(g k,0 , g k,1 , g k,2 , g k,3 , g k,4 ), are as follows:
g 0 =(1, 0, 1, 0, 1)
g 1 =(1, 0, 1, 1, 1)
g 2 =(1, 1, 0, 1, 1)
g 3 =(1, 1, 1, 1, 1)
g 4 =(1, 1, 0, 0, 1).
2. The method of claim 1 , wherein the rate 1/5 convolutional code includes tail-biting.
3. The method of claim 2 , wherein the tail-biting is configured whereby, depending on the information bits, an initial state of the encoding is set such that the initial state and a final state are equal.
4. The method of claim 3 , wherein the initial state S 0 , S 1 , S 2 , S 3 is set as
S 0 =u 15 , S 1 =u 14 , S 2 =u 13 , S 3 =u 12 .
5. The method of claim 1 , wherein the physical layer header information bits comprise a seven bit modulation and coding field indicating modulation and coding schemes applied to a data payload portion of the physical layer data frame, a one bit type field indicating whether a normal or a short codeblock is employed, and an eight bit stream identification field indicating a source data stream from which the data payload portion of the physical layer data frame originated.
6. An apparatus comprising:
an encoder configured to encode a physical layer header of a physical layer data frame, wherein the physical layer header comprises sixteen information bits u i , i=0,1,2, . . . ,15, and the encoding is based on a rate 1/5 convolutional code, wherein, for each information bit u i , i=0,1,2, . . . ,15, five associated parity bits p i,k , k=0,1, 2, 3,4 are generated, resulting in a first codeword of 80 codebits;
a repeater device configured to repeat the codebits of the first codeword to generate a physical layer signaling codeword for transmission of the physical layer data frame over a channel of a communications network; and
a parity bit generator configured to generate, for each information bit u i , i=0, 1, 2, . . . , 15, five associated parity bits p i,k , k=0, 1, 2, 3, 4, as follows:
p i,k =( u i *g k,0 )( S 0 *g k,1 )( S 1 *g k,2 )( S 2 *g k,3 )( S 3 *g k,4 ),
where S 0 =u i-1 , S 1 =u i-2 , S 2 =u i-3 , S 3 =u i-4 , and
wherein generator polynomials for g k =(g k,0 , g k,1 , g k,2 , g k,3 , g k,4 ), are as follows:
g 0 =(1, 0, 1, 0, 1)
g 1 =(1, 0, 1, 1, 1)
g 2 =(1, 1, 0, 1, 1)
g 3 =(1, 1, 1, 1, 1)
g 4 =(1, 1, 0, 0, 1).
7. The apparatus of claim 6 , wherein the rate 1/5 convolutional code includes tail-biting.
8. The apparatus of claim 7 , wherein the tail-biting is configured whereby, depending on the information bits, an initial state of the encoding is set such that the initial state and a final state are equal.
9. The apparatus of claim 8 , wherein the initial state S 0 , S 1 , S 2 , S 3 is set as
S 0 =u 15 ,S 1 =u 14 ,S 2 =u 13 ,S 3 =u 12 .
10. The apparatus of claim 6 , wherein the physical layer header information bits comprise a seven bit modulation and coding field indicating modulation and coding schemes applied to a data payload portion of the physical layer data frame, a one bit type field indicating whether a normal or a short codeblock is employed, and an eight bit stream identification field indicating a source data stream from which the data payload portion of the physical layer data frame originated.