Orthogonal Cover Code Sequences for PUCCH PAPR Reduction
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Solution Overview
Problem
Existing orthogonal cover code (OCC) sequences for physical uplink control channel (PUCCH) transmissions in wireless communication systems, such as those used in NR release 15, suffer from increased peak to average power ratios (PAPR) when combined with certain modulation schemes like pi/2-BPSK and QPSK, leading to performance issues.
Innovation Solution
A new set of OCC sequences is designed to achieve target PAPRs for a plurality of different modulation schemes, specifically reducing PAPR while maintaining frequency orthogonality, by selecting OCC sequences from a first set that optimize power distribution across subcarriers for uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing OCC sequences are used for PUCCH transmissions, then frequency orthogonality is maintained, but peak to average power ratio (PAPR) increases leading to performance issues
Solution Approach 1:
The patent modifies the OCC sequences by changing their mathematical parameters and structure. Specifically, it introduces new OCC sequences with different phase rotations and amplitude distributions that maintain orthogonality while reducing PAPR. The patent applies parameter transformations to the existing OCC sequences to achieve lower peak power ratios without sacrificing the orthogonality property that enables frequency multiplexing.
Solution Approach 2:
The patent creates composite OCC sequences by combining multiple mathematical components. The new OCC sequences are constructed as composite structures that integrate phase rotation factors, amplitude weighting, and orthogonal code elements. This composite approach allows the sequences to simultaneously achieve low PAPR and maintain frequency orthogonality, resolving the contradiction between these two requirements.
2Reliability
If OCC sequences are optimized for one modulation scheme, then PAPR is reduced for that scheme, but performance degrades for other modulation schemes
Solution Approach 1:
The patent designs OCC sequences that serve multiple modulation schemes simultaneously. The new OCC sequences are constructed to be universally applicable across different modulation types (QPSK, 16QAM, 64QAM, etc.) while maintaining optimized PAPR performance for each. This is achieved by creating sequences with mathematical properties that are invariant to modulation scheme changes, allowing a single OCC sequence design to benefit multiple modulation schemes.
Solution Approach 2:
The patent introduces dynamic adaptability in OCC sequence selection. The system can dynamically choose appropriate OCC sequences based on the specific modulation scheme being used and the current channel conditions. This dynamic approach ensures that the most suitable OCC sequence is selected for each transmission, optimizing power efficiency while maintaining compatibility across different modulation schemes.
Data Source
AI summary
The present disclosure relates generally to wireless communication systems, and more particularly, to a design for generating and utilizing orthogonal cover code (OCC) sequences for physical uplink control channel (PUCCH) transmissions. An exemplary method includes a user equipment (UE) selecting an orthogonal cover code (OCC) sequence for an uplink transmission, wherein the OCC sequence is selected from a first set of OCC sequences designed to achieve target peak to average power ratios (PAPRs) for a plurality of different modulation schemes; and transmitting the uplink transmission, via a wireless medium, with one of the modulation schemes using the selected OCC sequence.