LDPC Parameter Signaling for OFDM Packet Decoding Compatibility
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Solution Overview
Problem
The proposed IEEE 802.11ac standard introduces changes to the conventional LDPC encoding process, leading to recognition issues and mapping problems for receiving devices, which may fail to derive necessary LDPC coding parameters.
Innovation Solution
The method involves determining and signaling the necessary LDPC coding parameters, such as Nsym, Ncw, Nshrt, and Npunc, within the LDPC signal, allowing receiving devices to derive all pertinent parameters, including Nldpc_ext, to ensure compatibility and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional LDPC encoding process is changed in the proposed IEEE 802.11ac standard, then data throughput and performance are improved, but receiving devices may not recognize signaling components and mapping issues remain
Solution Approach 1:
The transmitting device determines and signals all necessary LDPC coding parameters (Nsym, Ncw, Nshrt, Npunc) in advance within the signal field before data transmission. This preliminary action ensures that receiving devices have all required parameters available before decoding, preventing recognition failures and mapping issues while enabling the use of improved LDPC encoding processes for higher throughput
2Productivity
If signaling components are modified to improve LDPC encoding efficiency, then encoding performance is enhanced, but receiving devices fail to derive necessary LDPC coding parameters
Solution Approach 1:
The signal field structure is designed to carry multiple LDPC parameters (Nsym, Ncw, Nshrt, Npunc) simultaneously, making it a universal signaling mechanism that provides all necessary information for various LDPC decoding scenarios. This multi-functional signaling approach ensures that receiving devices can derive all required parameters regardless of the specific LDPC encoding configuration used by the transmitter
Data Source
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AI summary
A system and method for transmitting LDPC parameters is provided. In the method, an initial number of OFDM symbols (Nsym_init) is determined for a packet that is based on the number of information bits to be delivered in the packet. An STBC value is also determined. A number of extra symbols (Nsym_ext) value is generated based on the Nsym_init value, wherein a Nsym value is based on said Nsym_init value and said Nsym_ext value. An Nldpc_ext value is determined based on the STBC value and the Nsym_ext value for purposes of determining LDPC parameters associated with the packet.