HS-SCCH Part 1 Modulation Bit Reinterpretation for 64QAM
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Solution Overview
Problem
Current HSDPA systems face challenges in integrating 64QAM modulation support without increasing the number of HS-SCCH formats or reducing error correction coding, especially with the introduction of MIMO techniques, which complicates the modulation indication in the HS-SCCH structure.
Innovation Solution
Interpreting the existing modulation indication bit as a QPSK/xQAM indication if both UE and cell support 64QAM, allowing the 7 code information bits in the HS-SCCH part 1 structure to be used for either QPSK interpretation or 6 bits for code information with an additional bit for 16QAM/64QAM selection, without requiring additional bits or reduced error correction coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 64QAM modulation indication is added to HS-SCCH Part 1, then modulation capability is improved, but device complexity increases due to requiring additional bits or reduced error correction coding
Solution Approach 1:
The existing modulation indication bit in HS-SCCH Part 1 is made universal by reinterpreting its meaning based on capability flags. The same bit structure serves both traditional QPSK/16QAM indication and the new 64QAM indication, eliminating the need for separate signaling structures while expanding modulation capability.
Solution Approach 2:
The interpretation parameters of the modulation indication bit are changed dynamically based on capability information. When both UE and cell support 64QAM, the bit is reinterpreted to indicate QPSK/xQAM selection instead of the traditional QPSK/16QAM selection, allowing 64QAM capability to be signaled without adding physical bits.
2Adaptability or versatility
If additional bits are added to HS-SCCH Part 1 for 64QAM indication, then modulation capability is improved, but error correction protection is reduced
Solution Approach 1:
The existing modulation indication bit performs multiple functions: it indicates QPSK/16QAM modulation when 64QAM is not supported, and indicates QPSK/xQAM selection when 64QAM is supported. This universal usage maintains the original error correction coding structure while enabling 64QAM capability.
Solution Approach 2:
Instead of adding a new bit structure, the invention reuses the existing modulation indication bit structure. The same bit position and coding structure are copied and reinterpreted based on capability conditions, preserving error correction protection while adding functional capability.
3Adaptability or versatility
If HS-SCCH Part 1 structure is modified to support MIMO and 64QAM, then adaptability is improved, but the number of HS-SCCH formats increases
Solution Approach 1:
The invention makes the existing HS-SCCH Part 1 structure universal by enabling it to convey both MIMO antenna weight information and 64QAM modulation indication through the same bit structure. The modulation indication bit works in conjunction with MIMO signaling without requiring separate format definitions, reducing the total number of HS-SCCH formats needed.
Data Source
AI summary
The modulation indication bit is interpreted as a QPSK/xQAM modulation indication if both the user equipment and the serving cell support 64QAM modulation, such that if QPSK is indicated, the 7 code-set information bits in the HS-SCCH part 1 structure is interpreted as is presently interpreted today as defined in the 3GPP release 5 specification, and if xQAM is indicated, the 7 code-set information bits in the HS-SCCH part 1 structure is interpreted such that only 6 bits are used for code information and one bit is stolen for use for the 16QAM/64QAM selection.