LDPC Parameter Signaling Using OFDM Symbol Mapping
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Solution Overview
Problem
The proposed IEEE 802.11ac standard introduces changes to the conventional LDPC encoding process, leading to issues with LDPC decoding on the receiving side, where the device may not recognize new signaling components or experience mapping issues between LDPC components, affecting data transmission.
Innovation Solution
A method and system for transmitting LDPC signals that determine LDPC coding parameters by calculating an initial number of OFDM symbols and extra symbols, generating an Nldpc_ext value based on STBC and extra symbols, to ensure accurate LDPC parameter determination and transmission, compatible with both IEEE 802.11n and 802.11ac standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional LDPC encoding process is changed to improve data transmission performance, then data throughput is improved, but the receiving device may not recognize new signaling components or experience mapping issues between LDPC components
Solution Approach 1:
The transmitting device performs preliminary calculations to determine the initial number of OFDM symbols (Nsym_init) and extra symbols (Nsym_ext) before transmission. By pre-determining these parameters and encoding them into the transmitted signal, the receiving device can derive all necessary LDPC coding parameters without encountering recognition issues, thus maintaining reliability while enabling improved throughput through optimized symbol allocation.
2Measurement precision
If more signaling components are added to convey LDPC parameters, then decoding accuracy is improved, but the number of bits needed for parameter determination increases
Solution Approach 1:
The invention changes the parameter representation by encoding LDPC parameters in terms of OFDM symbol counts (Nsym_init and Nsym_ext) rather than traditional bit-based parameters. This parameter transformation allows the receiving device to derive all LDPC coding parameters with fewer transmitted bits, as the symbol-based representation is more compact and directly usable for decoding operations.
3Productivity
If puncturing is increased to reduce overhead, then data throughput is improved, but data reliability deteriorates
Solution Approach 1:
By changing the parameter representation to symbol-based counts (Nsym_init and Nsym_ext), the system achieves more efficient resource allocation. This allows for optimized puncturing patterns that reduce overhead while maintaining reliability, as the symbol-based parameters enable more precise control over the allocation of redundant bits versus data bits in the transmitted signal.
Data Source
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.