Method and system for allocating convolutional encoded bits into symbols before modulation for wireless communication
View Patent ↗A method and corresponding apparatus for encoding a sequence of bits for transmission as symbols, some of the bit positions of the symbols having a higher bit error rate than other bit positions. A plurality of sequences of bits is provided using a convolutional encoder, in response to a sequence of input bits, each sequence of bits being defined by a predetermined generator polynomial having a predetermined level of sensitivity to puncturing. Then the bits of each sequence of bits are mapped to symbol positions based on the level of sensitivity of the generator polynomial defining the sequence of bits. With interleaving, the mapping of bits of each sequence of bits to symbol positions can precede a symbol interleaving step, or it can follow a bit interleaving step.
1. A method of encoding a sequence of bits for transmission via a transmission channel as symbols consisting of a plurality of bits, some of the bit positions of the symbols having a higher bit error rate than other bit positions, the method comprising:
a) a step of providing a plurality of sequences of bits using a convolutional encoder, in response to a sequence of input bits, each sequence of bits being defined by a predetermined generator polynomial having a predetermined level of sensitivity to puncturing; and
b) a step of mapping the bits of each sequence of bits to symbol positions based on the level of sensitivity of the generator polynomial defining the sequence of bits.
2. A method as in claim 1 , further comprising a step of interleaving.
3. A method as in claim 2 , wherein the interleaving is bit interleaving, and wherein the step of providing a mapping is performed after the step of bit interleaving.
4. A method as in claim 2 , wherein the interleaving is symbol interleaving, and wherein the step of providing a mapping is performed before the step of symbol interleaving.
5. A method as in claim 2 , wherein, in the step of providing a plurality of sequences of bits using a convolutional encoder, at least one of the sequences of bits are punctured after using the convolutional encoder in order to fit the at least one sequence of bits into a transmission channel.
6. A method as in claim 5 , wherein the amount of puncturing of each sequence depends on the level of sensitivity of the polynomial defining the sequence.
7. A method as in claim 1 , wherein, in the step of providing a plurality of sequences of bits using a convolutional encoder, at least one of the sequences of bits are punctured after using the convolutional encoder in order to fit the at least one sequence of bits into a transmission channel.
8. A method as in claim 7 , further comprising a step of interleaving.
9. A method as in claim 8 , wherein the interleaving is bit interleaving, and wherein the step of providing a mapping is performed after the step of bit interleaving.
10. A method as in claim 8 , wherein the interleaving is symbol interleaving, and wherein the step of providing a mapping is performed before the step of symbol interleaving.
11. A method as in claim 7 , wherein the amount of puncturing of each sequence depends on the level of sensitivity of the polynomial defining the sequence.
12. A method as in claim 1 , wherein, in the step of providing output bits from the plurality of sequences of bits, punctured bits are inserted into at least one of the sequences of bits before using the convolutional decoder.
13. A method of decoding a sequence of bits encoded for transmission via a transmission channel as symbols consisting of a plurality of bits, some of the bit positions of the symbols having a higher bit error rate than other bit positions, the method comprising:
a) a step, responsive to received symbols, of demapping the symbols back to a plurality of sequences of bits, each sequence of bits being defined by a predetermined generator polynomial having a predetermined level of sensitivity to puncturing, the demapping based on the level of sensitivity of a generator polynomial defining a respective one of the sequences of bits; and
b) a step, responsive to the plurality of sequences of bits, of providing outputs bits using a convolutional decoder.
14. A method as in claim 13 , further comprising a step of deinterleaving.
15. A method as in claim 14 , wherein the interleaving is bit deinterleaving, and wherein the step of demapping is performed before the step of bit deinterleaving.
16. A method as in claim 12 , wherein the deinterleaving is symbol deinterleaving, and wherein the step of demapping is performed after the step of symbol deinterleaving.
17. A transmitting apparatus for encoding a sequence of bits for transmission via a transmission channel as symbols consisting of a plurality of bits, some of the bit positions of the symbols having a higher bit error rate than other bit positions, the apparatus comprising:
a) means for providing a plurality of sequences of bits using a convolutional encoder, in response to a sequence of input bits, each sequence of bits being defined by a predetermined generator polynomial having a predetermined level of sensitivity to puncturing; and
b) means for mapping the bits of each sequence of bits to symbol positions based on the level of sensitivity of the generator polynomial defining the sequence of bits.
18. A transmitting apparatus as in claim 17 , further comprising means for interleaving.
19. A transmitting apparatus as in claim 18 , wherein the means for interleaving performs bit interleaving, and wherein the means for mapping is operative after the means for interleaving.
20. A transmitting apparatus as in claim 18 , wherein the means for interleaving performs symbol interleaving, and wherein the means for providing a mapping is operative before the means for interleaving.
21. A transmitting apparatus as in claim 18 , wherein, the means for providing a plurality of sequences of bits using a convolutional encoder includes, after the convolutional encoder, means for puncturing at least one of the sequences of bits in order to fit the at least one sequence of bits into a transmission channel.
22. A transmitting apparatus as in claim 21 , wherein the means for puncturing provides puncturing of each sequence in an amount that depends on the level of sensitivity of the polynomial defining the sequence.
23. A transmitting apparatus as in claim 17 , wherein, the means for providing a plurality of sequences of bits using a convolutional encoder includes, after the convolutional encoder, means for puncturing at least one of the sequences of bits in order to fit the at least one sequence of bits into a transmission channel.
24. A transmitting apparatus as in claim 23 , further comprising means for interleaving.
25. A transmitting apparatus as in claim 24 , wherein the means for interleaving performs bit interleaving, and wherein the means for providing a mapping is operative after the means for interleaving.
26. A transmitting apparatus as in claim 24 , wherein the means for interleaving performs symbol interleaving, and wherein the means for providing a mapping is operative before the means for interleaving.
27. A transmitting apparatus as in claim 23 , wherein the means for puncturing provides puncturing of each sequence in an amount that depends on the level of sensitivity of the polynomial defining the sequence.
28. A system for wireless communication, comprising a base station and a mobile station, wherein either the base station or the mobile station includes a transmitting apparatus as claimed in claim 17 .
29. A receiving apparatus for decoding a sequence of bits encoded for transmission via a transmission channel as symbols consisting of a plurality of bits, some of the bit positions of the symbols having a higher bit error rate than other bit positions, the apparatus comprising:
a) means, responsive to received symbols, for demapping the symbols back to a plurality of sequences of bits, each sequence of bits being defined by a predetermined generator polynomial having a predetermined level of sensitivity to puncturing, the demapping based on the level of sensitivity of a generator polynomial defining a respective one of the sequences of bits; and
b) means, responsive to the plurality of sequences of bits, for providing outputs bits using a convolutional decoder.
30. A receiving apparatus as in claim 29 , further comprising means for deinterleaving.
31. A receiving apparatus as in claim 30 , wherein the means for deinterleaving is bit deinterleaving, and wherein the means for demapping is performed before the step of bit deinterleaving.
32. A receiving apparatus as in claim 30 , wherein the means for deinterleaving performs symbol deinterleaving, and wherein the means for demapping is operative after the means for deinterleaving.
33. A receiving apparatus as in claim 29 , wherein, the means for providing output bits using a convolutional decoder includes, before the convolutional decoder , means for inserting bits into at least one of the sequences of bits.
34. A system for wireless communication, comprising a base station and a mobile station, wherein either the base station or the mobile station includes a receiving apparatus as claimed in claim 29 .