LDPC Ranging Signals for Precise Power and Timing Adjustment
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Solution Overview
Problem
Current communication systems face challenges in accurately determining operational parameters for data transmission between devices, particularly in terms of power and timing, due to limitations in ranging processes which are not effectively fine-tuned.
Innovation Solution
The implementation of Low Density Parity Check (LDPC) coded signals, including initial and fine ranging signals, using specific LDPC codes characterized by triangular matrices with Cyclic Shifted Identity sub-matrices, to facilitate precise power and timing adjustments through a method involving bit filling, encoding, shortening, and puncturing, along with orthogonal frequency division multiplexing (OFDM) and multiple access (OFDMA) techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ranging processes are used to determine operational parameters, then the ranging process is simple, but the accuracy of power and timing determination is insufficient
Solution Approach 1:
The patent applies preliminary action by performing bit filling before encoding, where additional bits are inserted into the information sequence to enable more accurate power and timing estimation. This pre-processing step prepares the signal in advance to facilitate more precise ranging measurements without requiring complex post-processing operations.
Solution Approach 2:
The patent segments the LDPC codeword into multiple parts (information bits and parity bits) and applies different processing to each segment. The information bits undergo bit filling and encoding, while parity bits are generated separately and punctured differently. This segmentation allows optimized processing for power and timing determination in different parts of the signal.
2Manufacturing precision
If LDPC coding with bit filling and puncturing is implemented, then power and timing adjustment accuracy is improved, but the encoding complexity increases
Solution Approach 1:
Bit filling is performed as a preliminary action before LDPC encoding, where specific bits are inserted at predetermined positions in the information sequence. This pre-arranged structure facilitates more accurate power and timing estimation during ranging while maintaining a systematic encoding process that can be efficiently implemented.
Solution Approach 2:
The patent changes the parameters of the LDPC code by using different code rates and puncturing patterns. By adjusting the amount of puncturing and the specific bits retained, the system can optimize the balance between coding gain (which improves power and timing accuracy) and processing complexity. The code rate becomes a variable parameter that can be adapted to different ranging requirements.
3Reliability
If fine ranging signals are transmitted with optimized LDPC codes, then the reliability of data transmission is enhanced, but the signal processing time increases
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and pre-arranging the bit filling patterns and puncturing sequences before actual transmission. This preparation work is done in advance so that during fine ranging operations, the processing can proceed more efficiently with reduced real-time computation requirements, thus maintaining reliability while reducing processing time.
Solution Approach 2:
The patent introduces dynamic elements by allowing the fine ranging signals to be transmitted at different power levels and timing offsets based on initial ranging results. The system dynamically adjusts transmission parameters to optimize reliability for different channel conditions and distances, rather than using fixed parameters for all scenarios.
Data Source
AI summary
A communication device (device) includes a processor configured to generate an initial ranging LDPC coded signal based on a first LDPC code and then transmits the initial ranging LDPC coded signal to another device (e.g., via a communication interface) for use by the other device for coarse power and timing adjustment. Then, the processor processes a received transmit opportunity signal to identify a transmit opportunity time period. The processor then generates a fine ranging LDPC coded signal based on a second LDPC code and transmits the fine ranging LDPC coded signal to the other device during the transmit opportunity time period for use by the other device for fine power and timing adjustment. In some instances, the processor may be configured to generate one or more wideband probe signals for transmission to the other device in conjunction with or instead of the fine ranging LDPC coded signals.