1. A method for encoding a rate-compatible block Low Density Parity Check (LDPC) code, the method comprising the steps of:
designing, by a puncturing unit, specific LDPC codes for a predetermined number of coding rates, and generating a pruning pattern by comparing information node degrees of the predetermined number of LDPC codes;
matching, by the puncturing unit, check node degrees of the predetermined number of LDPC codes;
generating a predetermined number of puncturing patterns according to the check node degrees when the matched check node degrees are calculated;
determining, by the puncturing unit, whether a first condition given for the generated puncturing patterns is satisfied; and
determining the generated puncturing patterns as rate-compatible puncturing patterns when the puncturing patterns satisfy the first condition.
2. The method of claim 1, further comprising generating rate-compatible puncturing patterns according to a second condition given for the predetermined number of the generated puncturing patterns when the puncturing patterns do not satisfy the first condition.
3. The method of claim 2, wherein the second condition represents a condition of generating rate-compatible puncturing patterns while maintaining a property of a puncturing pattern corresponding to a low coding rate.
4. The method of claim 1, wherein the step of generating a pruning pattern comprises generating a pruning pattern by comparing degree distribution of each variable node, wherein the pruning pattern reduces the degree of the variable node.
5. The method of claim 1, wherein the step of matching check node degrees comprises matching a number of \u20181\u2019s per row of a predetermined number of parity check matrixes, wherein the matched check node degrees are calculated by an equation
dc=gcd(dc,1\u22122,dc,2\u22122, . . . , dc,m\u22122)+2
where dc denotes a matched check node degree.
6. The method of claim 1, further comprising calculating the matched check node degree, and converting the LDPC codes into a predetermined number of punctured LDPC codes according to the calculated check node degree.
7. The method of claim 6, wherein the LDPC code converting step is differently applied according to structure of the LDPC codes.
8. The method of claim 1, wherein the puncturing pattern generating step comprises combining a predetermined number of punctured LDPC codes changed according to the check node degree, into one rate-compatible LDPC code.
9. The method of claim 1, wherein the first condition is defined so for all i, a puncturing pattern (Pi) is a prime factor of (Pj), where j=i+1, . . . , m.
10. An apparatus for encoding a rate-compatible block Low Density Parity Check (LDPC) code, the apparatus comprising:
an encoder for encoding information data into coded symbols with a predetermined coding scheme;
a puncturing and pruning unit for puncturing a predetermined number of coded symbols from the coded symbols received from the encoder, the predetermined number corresponding to coding rate information set in a system; and
a modulator for modulating the coded symbols into modulation symbols with a predetermined modulation scheme,
wherein the puncturing and pruning unit generates LDPC codes for a predetermined number of coding rates, generates a pruning pattern by comparing information node degrees of a predetermined number of LDPC codes, matches check node degrees of the predetermined number of LDPC codes, generates a predetermined number of puncturing patterns according to the check node degree if the matched check node degree is calculated, compares the puncturing patterns with a first condition, and generates rate-compatible puncturing patterns according to the comparison result.
11. The apparatus of claim 10, wherein the puncturing and pruning unit performs pruning on an information node for generating an information node corresponding to a set degree from a mother code for each coding rate, and punctures a predetermined number of bits every parity bits given for each coding rate, for the parity bits left after the pruning.
12. The apparatus of claim 11, wherein the puncturing and pruning unit generates a pruning pattern by comparing degree distribution of each variable node, and reduces a degree of the variable node according to the pruning pattern.
13. The apparatus of claim 10, wherein the puncturing and pruning unit determines the generated puncturing patterns as the rate-compatible puncturing patterns when the puncturing patterns satisfy the first condition, and the puncturing and pruning unit generates rate-compatible puncturing patterns according to a second condition given for the puncturing patterns when the puncturing patterns do not satisfy the first condition.
14. The apparatus of claim 13, wherein the second condition represents a condition of generating rate-compatible puncturing patterns while maintaining a property of a puncturing pattern corresponding to a low coding rate.
15. The apparatus of claim 10, wherein the puncturing and pruning unit matches the check node degrees by matching a number of \u20181\u2019s per row of a predetermined number of parity check matrixes, wherein the matched check node degrees are calculated by the equation
dc=gcd(dc,1\u22122,dc,2\u22122, . . . , dc,m\u22122)+2
where dc denotes the matched check node degree.
16. The apparatus of claim 10, wherein the puncturing and pruning unit generates puncturing patterns by combining a predetermined number of punctured LDPC codes changed according to the check node degree, into one rate-compatible LDPC code.
17. The apparatus of claim 10, wherein the first condition is defined so for all i, a puncturing pattern (Pi) is a prime factor of (Pj), where j=i+1, . . . , m.
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. A device (10) for gripping and handling a metal container (26), said container (26) being obtained from an extruded, deep-drawn or deep-drawnwire-drawn metal rough piece, said device (10) being suitable for use with a high speed metal container deformation machine for performing a plurality of mechanical working sequences on the metal container (26), said device (10) including:
a) a first lower portion (12) adapted to interface-connect said device (10) to said high speed metal container deformation machine during the performance of the plurality of working sequences and during high speed transfer stages from one work station to the next of said machine; and
b) a second upper portion (16) including a retaining means adapted to mechanically firmly grip and stabilize said metal container (26) during the plurality of working sequences and high speed transfer stages of said metal container deformation machine, wherein said upper portion (16) has an interior with an inner surface having a diameter that progressively increases in the direction from the bottom of said metal container (26) toward the open top of the upper portion so as to define a taper for receiving said retaining means and to permit axial movement of said retaining means relative to the interior of said upper portion (16).
2. The device according to claim 1, wherein said lower portion (12) includes at least one reference member for the correct positioningbalancing of the device relative to a part bearing table (14) of said high speed metal container deformation machine.
3. The device according to claim 1, wherein said axially movable retaining means comprises a snap ring (24) axially arranged within said upper portion (16).
4. The device according to claim 3, wherein said snap ring (24) has an outer surface tapered to match the taper of the inner surface of said upper portion (16).
5. The device according to claim 3, wherein said snap ring (24) grips and stabilizes said metal container (26) along a limited length of a side surface of the metal container ranging from 10 to 35 mm.
6. The device according to claim 3, wherein said snap ring (24) is axially moved by an actuating means which cooperates with a return member to exert a thrusting action on a lower front of said snap ring opposed to an upper front of insertion of said metal container (26) into said snap ring.
7. The device according to claim 6, wherein said return member is a spring (38).
8. The device according to claim 3, which further includes a member (28) arranged coaxially within said snap ring (24), said member (28) having a hollow center and an upper portion defining a concave shaped disk (30).
9. The device according to claim 8, which further includes a stem (40) disposed in the hollow center of said member (28) and coaxial thereto which functions to extract the metal container (26) from said snap ring (24).
10. The device according to claim 9, wherein said stem (40) extracts the metal container (26) from said snap ring (24) by the axial movement of said stem in said snap ring so as to push said metal container from said snap ring, said stem movement being activated by actuating means cooperating with a stem return member.
11. The device according to claim 10, wherein said stem return member comprises a spring (52).
12. The device according to claim 8, which further includes a bearing (34) disposed between a lower surface of said concave shaped disk (30) and an upper front of a sleeve (32) within which said member (28) is disposed, thereby allowing the metal container (26) disposed on said disk (30) to be oriented in said device.