HARQ Bit Selection Layout for CTC Redundancy Versions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing Hybrid Automatic Repeat Request (HARQ) mechanisms in wireless communication systems, particularly those employing IEEE 802.16 standards, face performance issues due to the bit selection method used in Convolutional Turbo Code (CTC) encoding, which can negatively impact error correction efficiency.
Innovation Solution
A method involving the generation of redundancy versions by permuting and mapping subblocks into a circular buffer, allowing bit selection to start at a fixed position and offset for subsequent versions, optimizing the selection of redundancy versions for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bit selection method is used in CTC encoding for HARQ, then implementation is simple, but error correction performance deteriorates
Solution Approach 1:
The encoded bit sequence is divided into multiple subblocks (first subblock containing information bits, second and third subblocks containing parity bits). Different permutation operations are applied to different subblocks, allowing optimized bit selection for each redundancy version while maintaining manageable complexity
Solution Approach 2:
The patent pre-calculates and stores permutation patterns for different redundancy versions in lookup tables. During HARQ operation, the transmitter and receiver simply retrieve and apply the appropriate permutation pattern, avoiding complex real-time calculations while achieving optimal error correction performance
2Reliability
If multiple redundancy versions are transmitted with optimized bit selection, then data integrity is improved, but transmission overhead increases
Solution Approach 1:
Different portions of the encoded sequence are selectively transmitted for different redundancy versions. The bit selection patterns are designed to transmit the most useful bits for each specific retransmission scenario, avoiding redundant transmission of identical bits and reducing overall overhead while improving data integrity
Solution Approach 2:
The patent designs bit selection patterns that discard previously transmitted bits in subsequent redundancy versions, selecting only new complementary information. The receiver combines these non-redundant bits from multiple transmissions to recover the complete original data, minimizing total transmission overhead
Data Source
AI summary
Methods and apparatuses for encoding data in a wireless communication system including receiving an information sequence, and encoding the received information sequence to generate three subblocks of sequences. A first subblock of the three subblocks is the information sequence, a second subblock of the three subblocks is an encoded sequence, and a third subblock of the three subblocks is an interleaved and encoded sequence. The method further includes permuting the three subblocks of encoded sequences separately by subblock permutation, and continuously mapping the three subblocks into a circular buffer, the circular buffer including a first part, a second part, and a third part. Further, the method includes bit-selecting bits from the circular buffer, in a circular order corresponding to the first part, the second part, and the third part, to generate a first redundancy version and a second redundancy version, wherein bit-selection for a first redundancy version of the plurality of redundancy versions begins at a first position in the circular buffer, bit-selection for each successive redundancy version of the plurality of redundancy versions begins after a last position in the circular buffer corresponding to a previous redundancy version, and wherein, when a complete codeword is selected, bit-selection is offset from the first position by a fixed number of bits X. Finally, the method includes transmitting at least one redundancy version of the plurality of redundancy versions to at least one receiving device.