TD-SCDMA Rate Matching for Check Bit Puncturing Stability
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Solution Overview
Problem
The decoding performance of TD-SCDMA systems is severely degraded at certain specific data rates due to the puncturing ratio of check bits, leading to systematic bits being unprotected and unable to be checked, resulting in a loss of encoding gain.
Innovation Solution
A method for configuring services in TD-SCDMA systems that avoids puncturing ratios close to 7, by adjusting the check bit puncturing ratio within specific ranges and modifying the transport block sizes, ensuring each systematic bit is protected by check bits, and implementing alternative position determination for reserved check bits during rate matching to prevent performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the check bit puncturing ratio is set to certain specific values (close to 7), then the data rate is improved, but the decoding performance is severely degraded
Solution Approach 1:
The patent changes the puncturing ratio parameter from values close to 7 (which cause performance degradation) to values that are multiples of 7. This parameter change resolves the contradiction by finding specific values that maintain both high data rate and good decoding performance, avoiding the harmful range while preserving productivity.
2Productivity
If the puncturing ratio is increased to achieve higher data rates, then the encoding gain is lost due to systematic bits being unprotected, but increasing the puncturing ratio further reduces reliability
Solution Approach 1:
The patent applies local quality by differentiating the treatment of systematic bits and check bits. Systematic bits are protected from puncturing while check bits are punctured according to a specific ratio that is a multiple of 7. This localized protection strategy ensures that systematic bits remain protected (maintaining encoding gain) while achieving high data rates through selective puncturing of check bits.
3Device complexity
If the Turbo code internal interleaver is used as defined in the protocol, then the encoding structure is simplified, but the decoding performance is severely degraded at certain data rates
Solution Approach 1:
The patent changes the puncturing ratio parameter in the Turbo coding system to values that are multiples of 7, which resolves the performance degradation issue while maintaining the simple protocol-defined interleaver structure. This parameter change allows the system to achieve both low complexity and high reliability.
Data Source
AI summary
A method for configuring a service and a method and apparatus for rate matching in a TD-SCDMA system, this method for configuring the service includes: taking that a check bit puncturing ratio should be more than 7i+a or less than 7i−a as a newly added constraint condition, and the check bit puncturing ratios of each configured service being outside a range of [7i+a, 7i−a], the method for rate matching includes: when puncturing each path of check bits of the current data block, if a difference between a position Pk of kth reserved check bit calculated according to a method defined by the service and a previously determined position NPk−1 of k−1th reserved check bit is a positive integral multiple of 7, determining a position NPk of kth reserved check bit as Pk plus 1 or Pk minus 1, and Pk plus 1 and Pk minus 1 requiring carrying out alternately.