Wi-Fi Constellation Shaping Rate Matching for LDPC Compatibility
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining compatibility between LDPC rate matching and probability constellation shaping, leading to disruptions in the specific ratio between amplitude and sign bits, affecting data rates, signal quality, and range.
Innovation Solution
Implementing a rate matching algorithm that determines pre-FEC padding boundaries, codeword quantities, and post-FEC padding sizes based on estimated payload sizes after constellation shaping, along with signaling mechanisms to indicate constellation shaping combinations or states, ensuring compatibility between LDPC rate matching and probability constellation shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If probability constellation shaping is applied to change PHY payload size, then spectral efficiency and data rates are improved, but compatibility with LDPC rate matching is disrupted and the ratio between amplitude and sign bits is affected
Solution Approach 1:
The patent applies preliminary action by estimating the PHY payload size after constellation shaping before performing LDPC rate matching. This allows the system to pre-determine the number of codewords and padding bits needed, ensuring that the shaping operation and rate matching operation work together seamlessly. The estimator determines an estimated PHY payload size based on the shaped information bits, which is then used to configure the LDPC encoding parameters in advance.
Solution Approach 2:
The patent changes parameters by dynamically adjusting the LDPC rate matching parameters (number of codewords, pre-FEC padding bits, post-FEC padding bits) based on the estimated PHY payload size from constellation shaping. This parameter adaptation ensures that the LDPC code rate and structure are optimized to work with the shaped signal, maintaining the desired ratio between amplitude and sign bits while achieving the spectral efficiency gains from shaping.
2Ease of manufacture
If LDPC rate matching is performed with fixed parameters, then implementation simplicity is maintained, but flexibility to adapt to constellation shaping is reduced
Solution Approach 1:
The patent applies dynamics by making the LDPC rate matching parameters adaptive rather than fixed. The number of codewords, pre-FEC padding bits, and post-FEC padding bits are dynamically determined based on the estimated PHY payload size from constellation shaping. This dynamic parameter adjustment allows the system to flexibly adapt to different shaping configurations while maintaining a systematic implementation approach through the use of an estimator and standardized parameter determination rules.
3Productivity
If the PHY payload size is changed by constellation shaping, then spectral efficiency is improved, but the number of padding bits and codeword structure becomes complex to determine
Solution Approach 1:
The patent reduces complexity by performing preliminary estimation of the PHY payload size before LDPC rate matching. The estimator determines the estimated PHY payload size based on the shaped information bits, which then serves as the foundation for systematically calculating all subsequent parameters including the number of codewords, pre-FEC padding bits, and post-FEC padding bits. This preliminary determination simplifies the overall parameter selection process.
Solution Approach 2:
The patent uses feedback by having the estimator continuously determine the estimated PHY payload size based on the actual shaped information bits, and using this information to adjust the LDPC rate matching parameters. This feedback loop ensures that the parameters are consistently aligned with the shaping operation, automatically adapting to different shaping configurations without requiring complex manual configuration.
Data Source
AI summary
This disclosure provides methods, components, devices and systems for rate matching and signaling in probability constellation shaping in Wi-Fi systems. Some aspects more specifically relate to a rate matching algorithm and various rules, calculations, procedures, and signaling designs to support rate matching in conjunction with probability constellation shaping. In some examples, a wireless communication device functioning as a transmitter device may implement a rate matching algorithm to determine a pre-forward error correction (FEC) padding boundary, a pre-FEC padding size, a quantity of codewords, and a post-FEC padding size given a presumed payload size after shaping, a codeword size, and an effective code rate. Additionally, or alternatively, a wireless communication device may indicate information associated with an application of a constellation shaping. Such information may indicate a specific constellation shaping combination or whether constellation shaping is set to an ON or OFF sets, or both.