Virtual limited buffer modification for rate matching
View Patent ↗Virtual limited buffer modification for rate matching. A reduced-size memory module is employed within a communication device to assist in storage of log-likelihood ratios (LLRs) employed in accordance with turbo decoding. This architecture is also applicable to other types of error correction code (ECC) besides turbo code as well. The memory size is selected to match the number of coded bits (e.g., including information bits and redundancy/parity bits) that is included within a transmission. The received signals may be various transmissions made in accordance with hybrid automatic repeat request (HARQ) transmissions. When the LLRs calculated from a first HARQ transmission is insufficient to decode, those LLRs are selectively stored in the memory module. When LLRs corresponding to a second HARQ transmission is received, LLRs corresponding to both the first HARQ transmission and the second HARQ transmission are passed from the memory module for joint use in decoding.
1. An apparatus, comprising:
an input to receive a plurality of signals successively from a communication channel;
a memory to store selectively a plurality of log-likelihood ratios (LLRs) corresponding to an entire turbo encoded block such that at least a first of the plurality of LLRs corresponding respectively to a first of the plurality of signals and at least a second of the plurality of LLRs corresponding respectively to a second of the plurality of signals; and
a turbo decoder to employ the plurality of LLRs corresponding to the entire turbo encoded block, selectively stored in the memory, to make a plurality of estimates corresponding to each respective encoded bit of a plurality of encoded bits of the entire turbo encoded block; and wherein:
the turbo decoder to receive all of the plurality of LLRs corresponding to the entire turbo encoded block selectively stored in the memory after a last LLR of the plurality of LLRs corresponding to the entire turbo encoded block selectively stored in the memory.
2. The apparatus of claim 1 , wherein:
the memory includes only a number of memory locations to store one LLR for each respective encoded bit of the plurality of encoded bits of the entire turbo encoded block.
3. The apparatus of claim 1 , further comprising:
a demodulator to process the plurality of signals, successively from the communication channel, to generate a plurality of digital signals; and wherein:
the demodulator includes a metric generator to process a first of the plurality of digital signals to calculate the at least a first of the plurality of LLRs; and
the metric generator to process a second of the plurality of digital signals to calculate the at least a second of the plurality of LLRs.
4. The apparatus of claim 1 , further comprising:
an additional apparatus coupled to the apparatus via the communication channel; and wherein the additional apparatus including:
a zero padding module to pad at least one fill bit to an information block to generate a zero padded block;
a turbo encoding module to encode the zero padded block to generate a turbo coded block;
a dummy padding module to pad at least one pad bit to the turbo coded block to generate a dummy padded block;
a sub-block interleaving module to sub-block interleave the dummy padded block to generate a sub-block interleaved block; and
a circular buffer rate matching module to de-pad each fill bit and each dummy bit from the sub-block interleaved block to generate a sequence of bits for transmission to the apparatus within at least one of the plurality of signals.
5. The apparatus of claim 1 , wherein:
the apparatus being a communication device operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, and a fiber-optic communication system.
6. An apparatus, comprising:
an input to receive a plurality of signals successively from a communication channel;
a memory to store selectively a plurality of log-likelihood ratios (LLRs) corresponding to an entire turbo encoded block such that at least a first of the plurality of LLRs corresponding respectively to a first of the plurality of signals and at least a second of the plurality of LLRs corresponding respectively to a second of the plurality of signals; and
a turbo decoder to employ the plurality of LLRs corresponding to the entire turbo encoded block, selectively stored in the memory, to make a plurality of estimates corresponding to the entire turbo encoded block.
7. The apparatus of claim 6 , wherein:
the turbo decoder to receive all of the plurality of LLRs corresponding to the entire turbo encoded block selectively stored in the memory after a last LLR of the plurality of LLRs corresponding to the entire turbo encoded block selectively stored in the memory.
8. The apparatus of claim 6 , wherein:
the turbo decoder to employ the plurality of LLRs corresponding to the entire turbo encoded block, selectively stored in the memory, to make the plurality of estimates corresponding to each respective encoded bit of a plurality of encoded bits of the entire turbo encoded block.
9. The apparatus of claim 6 , wherein:
the memory includes only a number of memory locations to store one LLR for each respective encoded bit of a plurality of encoded bits of the entire turbo encoded block.
10. The apparatus of claim 6 , further comprising:
a demodulator to process the plurality of signals, successively from the communication channel, to generate a plurality of digital signals; and wherein:
the demodulator includes a metric generator to process a first of the plurality of digital signals to calculate the at least a first of the plurality of LLRs; and
the metric generator to process a second of the plurality of digital signals to calculate the at least a second of the plurality of LLRs.
11. The apparatus of claim 10 , further comprising:
a rate matching module to indicate a plurality of rate matching operational parameters to each of the demodulator, the memory, and the turbo decoder; and wherein:
the plurality of rate matching operational parameters corresponding to at least one of the plurality of signals successively received from the communication channel;
the demodulator to consider the plurality of rate matching operational parameters in accordance with processing at least one of the plurality of signals;
the turbo decoder to consider the plurality of rate matching operational parameters to make the plurality of estimates corresponding to the entire turbo encoded block; and
at least one of the rate matching operational parameters being at least one of a block size, a code rate, a shortening parameter, a zero padded bit parameter, a dummy bit parameter, a sub-block interleaving parameter, and a starting position parameter.
12. The apparatus of claim 6 , further comprising:
an additional apparatus coupled to the apparatus via the communication channel; and wherein the additional apparatus including:
a zero padding module to pad at least one fill bit to an information block to generate a zero padded block;
a turbo encoding module to encode the zero padded block to generate a turbo coded block;
a dummy padding module to pad at least one pad bit to the turbo coded block to generate a dummy padded block;
a sub-block interleaving module to sub-block interleave the dummy padded block to generate a sub-block interleaved block; and
a circular buffer rate matching module to de-pad each fill bit and each dummy bit from the sub-block interleaved block to generate a sequence of bits for transmission to the apparatus within at least one of the plurality of signals.
13. The apparatus of claim 6 , wherein:
the apparatus being a communication device operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, and a fiber-optic communication system.
14. A method for operating a communication device, the method comprising:
via an input of the communication device, receiving a plurality of signals successively from a communication channel;
within a memory of the communication device, selectively storing a plurality of log-likelihood ratios (LLRs) corresponding to an entire turbo encoded block such that at least a first of the plurality of LLRs corresponding respectively to a first of the plurality of signals and at least a second of the plurality of LLRs corresponding respectively to a second of the plurality of signals; and
employ the plurality of LLRs corresponding to the entire turbo encoded block, selectively stored in the memory, in accordance with turbo decoding to make a plurality of estimates corresponding to the entire turbo encoded block.
15. The method of claim 14 , further comprising:
performing turbo decoding using all of the plurality of LLRs corresponding to the entire turbo encoded block selectively stored in the memory after a last LLR of the plurality of LLRs corresponding to the entire turbo encoded block selectively stored in the memory.
16. The method of claim 14 , wherein:
the memory of the communication device includes only a number of memory locations to store one LLR for each respective encoded bit of a plurality of encoded bits of the entire turbo encoded block.
17. The method of claim 14 , further comprising:
processing the plurality of signals, successively from the communication channel, to generate a plurality of digital signals;
processing a first of the plurality of digital signals to calculate the at least a first of the plurality of LLRs; and
processing a second of the plurality of digital signals to calculate the at least a second of the plurality of LLRs.
18. The method of claim 17 , further comprising:
indicating a plurality of rate matching operational parameters corresponding to at least one of the plurality of signals successively received from the communication channel;
considering the plurality of rate matching operational parameters in accordance with processing at least one of the plurality of signals; and
considering the plurality of rate matching operational parameters in accordance with turbo decoding to make the plurality of estimates corresponding to the entire turbo encoded block, wherein at least one of the rate matching operational parameters being at least one of a block size, a code rate, a shortening parameter, a zero padded bit parameter, a dummy bit parameter, a sub-block interleaving parameter, and a starting position parameter.
19. The method of claim 14 , wherein:
an additional communication device coupled to the communication device via the communication channel; and
the additional communication device including:
a zero padding module to pad at least one fill bit to an information block to generate a zero padded block;
a turbo encoding module to encode the zero padded block to generate a turbo coded block;
a dummy padding module to pad at least one pad bit to the turbo coded block to generate a dummy padded block;
a sub-block interleaving module to sub-block interleave the dummy padded block to generate a sub-block interleaved block; and
a circular buffer rate matching module to de-pad each fill bit and each dummy bit from the sub-block interleaved block to generate a sequence of bits for transmission to the communication device within at least one of the plurality of signals.
20. The method of claim 14 , wherein:
the communication device operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, and a fiber-optic communication system.