Coding method and apparatus for data communication
A coding method and apparatus for data communication are provided, and may be applied to a plurality of scenarios such as a metro network, a backbone network, and a data center interconnection. As an example method, a first codeword is formed, where the first codeword includes n image bits and n to-be-transmitted bits. The n image bits are selected from to-be-transmitted bits in m source codewords. The m source codewords are formed before the first codeword. Both n and m are positive integers, and n>m; The n to-be-transmitted bits in the first codeword are sent. The bit in the first codeword can be protected by a plurality of codewords generated at different moments. In addition, the bit in the codeword can be protected by different quantities of codewords.
1. A coding method for data communication, wherein the method comprises:
forming, by a coder, m source codewords;
forming, by the coder, a first codeword based on the m source codewords, wherein the first codeword comprises n image bits and n to-be-transmitted bits, the n image bits are selected from the m source codewords formed before the first codeword, both n and m are positive integers, and n>m; and
sending, by an interface, the n to-be-transmitted bits in the first codeword without sending the n image bits in the first codeword.
2. The coding method according to claim 1 , wherein the n to-be-transmitted bits comprise p check bits and (n-p) information bits, and the p check bits are obtained by coding the n image bits and the (n-p) information bits, wherein p is a positive integer less than n.
3. The coding method according to claim 2 , wherein the n image bits comprise at least one image check bit and at least one image information bit, the at least one image check bit is selected from check bits in the m source codewords, and the at least one image information bit is selected from information bits in the m source codewords.
4. The coding method according to claim 3 , wherein a quantity of the at least one image check bits is the same as a quantity of the at least one check bits.
5. The coding method according to claim 1 , wherein a maximum value of a difference between quantities of bits provided by different source codewords in the m source codewords to the first codeword is greater than 1 bit.
6. The coding method according to claim 1 , wherein a code length of the first codeword is not greater than 2048, and a quantity of error correction bits is not greater than 5.
7. The coding method according to claim 1 , wherein in the m source codewords, a quantity of bits provided by at least one source codeword to the first codeword is different from a quantity of bits provided by another source codeword to the first codeword; or
each source codeword provides q bits to the first codeword, wherein q is an integer greater than 1, and n is an integer multiple of m.
8. The coding method according to claim 1 , wherein p_word first codewords constitute a first frame, and image bits in the p_word first codewords in the first frame are from to-be-transmitted bits in codewords in h second frames generated before the first frame, wherein both h and p_word are positive integers greater than 1.
9. The coding method according to claim 8 , wherein frame coordinates, row coordinates, and column coordinates of bits in the h second frames are obtained through calculation by using three functions: Φf( ) Φr( ), and Φc( ):
Φ f ([Frame,Row_str,Col_str])=Frame−1−frm_map(floor((Col_str+Δ)/ceiling( n/h )));
Φ r ([Frame,Row_str,Col_str])=(Col_str⊗Row_str)% p _word; and
Φ c ([Frame,Row_str,Col_str])= n+h *((Col_str+Δ)% ceiling( n/h ))+( h− 1−floor((Col_str+Δ)/ceiling( n/h ))),
wherein Frame is a frame coordinate, Row_str is a row coordinate, and Col_str is a column coordinate of an image bit in a codeword in the first frame, and Frame, Row_str, and Col_str are all integers, wherein Frame∈(−∞, +∞), Row_str∈[0, p_word−1], Col_str∈[0, 2n−1], frm_map (i)=h−1−i, and i∈[0, h−1]; and
if n/h is an integer, Δ=0;
if Col_str/floor (n/h)<ceiling (n/h) *h−n, Δ=floor (Col_str/floor (n/h)); or
if Col_str/floor (n/h) ceiling (n/h) *h−n, Δ=ceiling (n/h) *h−n.
10. The coding method according to claim 9 , wherein a set of column coordinates of image check bits in the p_word first codewords in the first frame is shown as follows:
Col_str_vec( i ,:)=[ i _base( i )−Range( i )+1: i _base( i )], wherein 0 i h− 1; and
if i <ceiling( n/h )* h−n, i _base( i )=( i+ 1)*ceiling( n/h )− i− 2; or
if i>=ceiling(n/h)*h−n, i_base(i)=(i+1)*ceiling(n/h)−ceiling(n/h)*h−n−1; and Range(i)=ceiling((p−i)/h)ROR(ceiling(n/h)*h−n), where ROR is cyclic right shifting of an array.
11. A coding apparatus for data communication, wherein the coding apparatus comprises a coder and an interface, and the coder is configured to:
form m source codewords;
form a first codeword based on the m source codewords, wherein the first codeword comprises n image bits and n to-be-transmitted bits, the n image bits are selected from the m source codewords formed before the first codeword, both n and m are positive integers, and n>m; and
the interface is configured to send the n to-be-transmitted bits in the first codeword without sending the n image bits in the first codeword.
12. The coding apparatus according to claim 11 , wherein the n to-be-transmitted bits comprise p check bits and (n−p) information bits, and the p check bits are obtained by coding the n image bits and the (n−p) information bits, wherein p is a positive integer less than n.
13. The coding apparatus according to claim 12 , wherein the n image bits comprise at least one image check bit and at least one image information bit, the at least one image check bit is selected from check bits in the m source codewords, and the at least one image information bit is selected from information bits in the m source codewords.
14. The coding apparatus according to claim 13 , wherein a quantity the at least one image check bits is the same as a quantity of the at least one check bits.
15. The coding apparatus according to claim 11 , wherein a maximum value of a difference between quantities of bits provided by different source codewords in the m source codewords to the first codeword is greater than 1 bit.
16. The coding apparatus according to claim 11 , wherein a code length of the first codeword is not greater than 2048, and a quantity of error correction bits is not greater than 5.
17. The coding apparatus according to claim 11 , wherein in the m source codewords, a quantity of bits provided by at least one source codeword to the first codeword is different from a quantity of bits provided by another source codeword to the first codeword; or
each source codeword provides q bits to the first codeword, wherein q is an integer greater than 1, and n is an integer multiple of m.
18. The coding apparatus according to claim 11 , wherein p_word first codewords constitute a first frame, and image bits in the p_word first codewords in the first frame are from to-be-transmitted bits in codewords in h second frames generated before the first frame, wherein both h and p_word are positive integers greater than 1.
19. The coding apparatus according to claim 18 , wherein frame coordinates, row coordinates, and column coordinates of bits in the h second frames are obtained through calculation by using three functions: Φf( ) Φr( ), and Φc( ):
Φ f ([Frame,Row_str,Col_str])=Frame−1−frm_map(floor((Col_str+Δ)/ceiling( n/h )));
Φ r ([Frame,Row_str,Col_str])=(Col_str⊗Row_str)% p _word; and
Φ c ([Frame,Row_str,Col_str])= n+h *((Col_str+Δ)% ceiling( n/h ))+( h− 1−floor((Col_str+Δ)/ceiling( n/h ))),
wherein Frame is a frame coordinate, Row_str is a row coordinate, and Col_str is a column coordinate of an image bit in a codeword in the first frame, and Frame, Row_str, and Col_str are all integers, wherein Frame∈(−∞, +∞), Row_str∈[0, p_word−1], Col_str∈[0, 2n−1], frm_map (i)=h−1−i, and i∈[0, h−1]; and
if n/h is an integer, Δ=0;
if Col_str/floor (n/h)<ceiling (n/h) *h−n, Δ=floor (Col_str/floor (n/h)); or
if Col_str/floor (n/h) ceiling (n/h) *h−n, Δ=ceiling (n/h) *h−n.
20. The coding apparatus according to claim 19 , wherein a set of column coordinates of image check bits in the p_word first codewords in the first frame is shown as follows:
Col_str_vec( i ,:)=[ i _base( i )−Range( i )+1: i _base( i )], wherein 0 i h− 1; and
if i <ceiling( n/h )* h−n, i _base( i )=( i+ 1)*ceiling( n/h )− i− 2; or
if i>=ceiling(n/h)*h−n, i_base(i)=(i+1)*ceiling(n/h)−ceiling(n/h)*h−n−1; and Range(i)=ceiling((p−i)/h)ROR(ceiling(n/h)*h−n), where ROR is cyclic right shifting of an array.