OFDM Waveform Integrity Check With Pre-Decoder LDPC Bypass
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Solution Overview
Problem
Existing wireless communication systems using zero tail (ZT) or unique word (UW) waveforms require efficient error detection and correction methods to maintain high reliability, flexibility, and coding rates, especially for diverse devices like M2M, MTC, and IoT, while minimizing resource usage and latency.
Innovation Solution
Implementing a pre-decoder data check to verify packet integrity before channel decoding, utilizing low-density parity-check (LDPC) encoding, cyclic redundancy check (CRC), and orthogonal frequency-division multiplexing (OFDM) to perform error detection and correction on received waveforms, allowing for flexible and efficient error checking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-decoder data check is implemented to bypass channel decoding for successful packets, then latency is reduced and productivity is improved, but device complexity increases due to additional checking mechanisms
Solution Approach 1:
The patent applies preliminary action by performing a pre-decoder data check using CRC or other error detection codes before channel decoding. This early verification allows the system to identify and handle successful packets without undergoing the full channel decoding process, thereby reducing latency for error-free transmissions while maintaining robust error correction capability when needed.
2Reliability
If LDPC encoding with CRC is used for error detection, then reliability is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent applies segmentation by dividing the error detection process into two stages: a lightweight pre-decoder check using simple CRC or parity checks, and a more comprehensive post-decoder verification using LDPC syndrome checking. This segmented approach allows the system to achieve high reliability through multiple layers of error detection while managing complexity by handling most packets at the simpler first stage.
Solution Approach 2:
The patent applies preliminary action by performing error detection using CRC or parity checks before channel decoding. This preliminary error detection filters out many error-free packets that would otherwise require full LDPC decoding, thereby improving reliability through multiple verification layers while reducing the processing burden on the more complex LDPC decoding mechanism.
3Reliability
If additional CRC or error check signals are appended to waveforms, then data integrity is improved, but resource usage increases
Solution Approach 1:
The patent applies universality by designing the pre-decoder check mechanism to serve multiple functions: it performs error detection, enables latency reduction through selective bypass of channel decoding, and provides flexibility for different device types and channel conditions. This multi-functional approach maximizes the value derived from the additional error check signals while minimizing redundant resource consumption.
4Adaptability or versatility
If flexible error checking is implemented for different device types, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by implementing configurable error checking parameters that can be dynamically adjusted based on device type, channel conditions, and service requirements. The system can adapt the strength and type of pre-decoder checks (e.g., simple parity vs. full CRC) to match the specific needs of different applications such as M2M, MTC, or wearable devices, thereby achieving high adaptability without requiring completely different error checking architectures for each device class.
Data Source
AI summary
A wireless transmit/receive unit (WTRU) may low-density parity-check (LDPC) encode data into LDPC blocks. Further, the WTRU may produce and append a cyclic redundancy check (CRC) to each of the LDPC blocks. Also, the WTRU may concatenate the plurality of LDPC blocks and appended CRCs. Additionally, the WTRU may produce information associated with error checks. Moreover, the WTRU may produce a codeword using a codebook. The codeword may be based on the information associated with the error checks. In addition, the WTRU may produce an orthogonal frequency-division multiplex (OFDM) signal by mapping the codeword and the concatenated plurality of LDPC blocks and appended CRCs onto resource elements of the OFDM signal. Further, the WTRU may transmit the produced OFDM signal. In a further example, the WTRU may produce an additional CRC in addition to the appended CRCs, and the produced OFDM signal may include the additional CRC.