1. A data transmission method comprising the following steps of:
A. segmenting data to be transmitted into information file segments with a length of Tb bits;
B. performing forward error correction (FEC) coding for Tb information bit sequences composed of bits in same positions in a plurality of continuous information file segments to generate Tb check bit sequences, generating check file segments with a length of Tb bits based on the Tb check bit sequences, and putting each bit of the check bit sequences in the same position in the check file segments as the corresponding information bit sequences; and
C. transmitting each of the information file segments and check file segments, and wherein
the number of bits contained in the information bit sequences is less than or equal to the maximum length of Kmax bits of the FEC-coded information bit sequences;
wherein in the step B, the operation of putting each bit of the check bit sequences in the same position in the check file segments as the corresponding information bit sequences comprises: putting a jth bit of a ith check bit sequence in a jth bit position of a jth check file segment, and a ith information bit sequence is composed of the ith bits in the plurality of continuous information file segments, where i=1, . . . , Tb;
wherein in the step C, the information file segments and check file segments are packaged in a transmission packet and transmitted, and a header of the transmission packet contains file segment serial numbers, which are serial numbers of the information file segments or check file segments; and
wherein, the data to be transmitted is divided into Z file blocks with each file block containing a plurality of continuous information file segments in the following manner:
a) calculating the total number Kt of the information file segments contained in the data to be transmitted based on a length of F bytes of the data to be transmitted: Kt=\u250cFT\u2510;
b) calculating the total number Z of the file blocks: Z=\u250cKtKmax\u2510; and
c) if KtKmax is an integer, then containing, in each file block, Kmax, information file segments; and
in the step B, performing the FEC coding for the plurality of information file segments contained in one file block to generate the check file segments of the file block, where T=Tb8 and \u250c\u25cf\u2510 represents rounding up.
2. The data transmission method according to claim 1, wherein if KtKmax is not an integer, the number of the information file segments contained in each file block is calculated in the following manner:
d) include KL=\u250cKtZ\u2510 information file segments into ZL file blocks and include KS=\u2514KtZ\u2518 information file segments into ZS file blocks; and
calculate ZL and ZS according to the following formulae:
if KL>KS, then ZL=(Kt\u2212KS\xd7Z)(KL\u2212KS), if KL=KS, then ZL=Z; Zs=Z\u2212ZL and \u2514\u25cf\u2518 represents rounding down.
3. The data transmission method according to claim 1, wherein the FEC coding uses system codes.
4. The data transmission method according to claim 3, wherein the FEC coding uses low density generator matrix codes (LDGC).
5. The data transmission method according to claim 1, wherein the header of the transmission packet includes a resource identifier for identifying the data to be transmitted and an update serial number for identifying version information of the data to be transmitted.
6. A data transmission apparatus comprising a packet packaging and transmitting unit, a data segmenting unit, a memory and a forward error correction (FEC) coding unit, wherein:
the data segmenting unit is used for segmenting data to be transmitted into information file segments with a length of Tb bits and storing the information file segments into the memory;
the FEC coding unit is used for performing FEC coding for Tb information bit sequences composed of bits in same positions in a plurality of continuous information file segments to generate Tb check bit sequences, generating check file segments with a length of Tb bits based on the Tb check bit sequences, and putting each bit of the check bit sequences according to the order thereof in the same position in the check file segments as the corresponding information bit sequences, where the check file segments are stored in the memory; and
the packet packaging and transmitting unit is used for transmitting each of the information file segments and check file segments in the memory;
and wherein the number of bits contained in the information bit sequences is less than or equal to the maximum length of Kmax bits in the FEC-coded information bit sequences;
wherein, the FEC coding unit putting each bit of the check bit sequences in the same position in the check file segments as the corresponding information bit sequences comprises: the FEC coding unit putting a jth bit of a ith check bit sequence in a ith bit position of a jth check file segment; the ith information bit sequence is composed of the ith bits in the plurality of continuous information file segments, where i=1, . . . , Tb; and
wherein, the parameter setting unit is used for calculating the total number Kt of the information file segments contained in the data to be transmitted based on a length of F bytes of the data to be transmitted: Kt=\u250cFT\u2510, and calculating the total number Z of the file blocks: Z=\u250cKtKmax\u2510; wherein if KtKmax is an integer, then each file block contains Kmax information file segments; and
the FEC coding unit performs the FEC coding for the Kmax information file segments in the same file block based on the number of the information file segments contained in the file blocks output by the parameter setting unit, to generate the check file segments of the file block;
where T=Tb8 and \u250c\u25cf\u2510 represents rounding up.
7. The data transmission apparatus according to claim 6, wherein
if KtKmax is not an integer, the parameter setting unit sets the number of the information file segments contained in ZL file blocks to be KL=\u250cKtZ\u2510 and sets the number of the information file segments contained in ZS file blocks to be KS=\u2514KtZ\u2518;
wherein if KL>KS, then ZL=(Kt\u2212KS\xd7Z)(KL\u2212KS), if KL=KS, then ZL=Z; Zs=Z\u2212ZL and \u2514\u25cf\u2518 represents rounding down;
the FEC coding unit performs the FEC coding for KL or KS information file segments in the same file block based on the number of the information file segments contained in the file blocks output by the parameter setting unit, to generate the check file segments of the file block.
8. The data transmission apparatus according to claim 6, wherein the data packaging and transmitting unit packages information file segments and check file segments into a transmission packet and transmits the transmission packet, wherein a header of the transmission packet contains file segment serial numbers, which are serial numbers of the information file segments or check file segments.
9. The data transmission apparatus according to claim 6, wherein the FEC coding unit performs the FEC coding using system codes.
10. The data transmission apparatus according to claim 9, wherein the FEC coding unit performs the forward error correction-coding using low density generator matrix codes (LDGC).
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An output shaft of a starting device (1) for a motor vehicle, comprising:
a mounting support;
a driving element integrally and non-movably attached to the mounting support for transmitting a rotation movement to a thermal engine; and
a track integrally and non-movably attached to the mounting support for transmitting a rotation movement to the mounting support, the track being driven by a freewheel (12) of a starter-head assembly of the starting device.
2. The output shaft according to claim 1, wherein the mounting support comprises a rear end and a deformed rear portion (162) at the rear end (160) thereof; and wherein the track comprises a material reception indentation receiving the deformed rear portion, the material reception indentation is at least partially formed on a rear face of the track.
3. Output shaft (14) according to claim 1, wherein the mounting support (16a) comprises a rear end (160a), and wherein the attached track (15a) comprises a fluted portion (154a) and the mounting support (16a) comprises, at its rear end (160a), a fluted rear portion (163a) able to cooperate with the fluted portion (154a) of the attached track (15a), and a holding element (21a) intended to lock the attached track (15a) in translation on the mounting support (16a).
4. The output shaft (14b) according to claim 1, wherein the mounting support (16b) comprises a front end (161b) and a deformed front portion (164b) at the front end (161b) thereof; and wherein the driving element (17b) comprises a material reception indentation (172b) receiving the deformed front portion (164b), the material reception indentation (172b) is at least partially formed on a rear face of the driving element (17b).
5. Output shaft (14b, 14c) according to claim 1, wherein the mounting support (16c) comprises a front end (161c), and wherein the driving element (17c) comprises a fluted portion (174c) and the mounting support (16c) comprises, at its front end (161c), a fluted front portion (164c) able to cooperate with the fluted portion (174c) of the driving element (17c) and a holding element (25c) intended to lock the driving element (17c) in translation on the mounting support (16c).
6. A starting device (1) for a motor vehicle, comprising a starter-head assembly (10) intended to drive the output shaft (14, 14a, 14b, 14c) according to claim 1.
7. Starting device (1) according to claim 6, comprising:
a housing (13) in which the output shaft (14, 14a, 14b, 14c) is at least partially mounted,
the housing (13) comprising an orifice (1164b) able to have the output shaft (14, 14a, 14b, 14c) pass through it,
wherein the housing (13) comprises at least one means (24) of fixing the driving element (17, 17b, 17c) intended to fix said driving element (17, 17b, 17c) in an idle position.
8. The output shaft according to claim 1, wherein the track is integrally and non-movably attached and secured to the mounting support by local deformation of material of the mounting support.
9. The output shaft according to claim 8, wherein the mounting support comprises a rear end and a deformed rear portion at the rear end thereof; and wherein the track comprises a material reception indentation receiving the deformed rear portion, the material reception indentation is at least partially formed on a rear face of the track.
10. The output shaft according to claim 9, wherein the track is made of material having hardness greater than hardness of the material of the mounting support.
11. The output shaft according to claim 8, wherein the driving element is integrally and non-movably attached and secured to the mounting support by local deformation of the material of the mounting support.
12. The output shaft according to claim 11, wherein the driving element is made of material having hardness equal or greater than hardness of material of the mounting support.
13. The output shaft according to claim 1, wherein the mounting support comprises a rear end and a deformed rear portion at the rear end thereof;
wherein the track comprises a material reception indentation receiving the deformed rear portion, the material reception indentation is at least partially formed on a rear face of the track;
wherein the driving element is attached and secured to the mounting support by local deformation of the material of the mounting support;
wherein the mounting support comprises a front end and a deformed front portion at the front end thereof; and
wherein the driving element comprises a material reception indentation receiving the deformed front portion, the material reception indentation is at least partially formed on a rear face of the driving element.