LDPC FEC Switching for Varying NOMA User Loads
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Solution Overview
Problem
Conventional Non-Orthogonal Multiple Access (NOMA) systems face challenges in adaptiveness due to fixed system parameters, leading to under-utilization of resources during light loading intervals, as they are designed for worst-case scenarios, failing to effectively adapt to changing environments such as varying numbers of concurrent users.
Innovation Solution
The implementation of optimized Low-Density Parity-Check (LDPC) Forward Error Correction (FEC) codes with adjustable bit node degrees, selected based on the target average number of simultaneous users, allowing for dynamic adaptation of FEC codes to optimize performance across different user scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If system parameters are fixed for worst-case scenario design, then reliability is improved, but resource utilization deteriorates during light loading intervals
Solution Approach 1:
The patent implements dynamic adaptation of FEC code parameters (code rate, block length) based on the number of simultaneous users. The system transitions from fixed worst-case parameters to dynamically adjustable parameters that adapt to current loading conditions, resolving the contradiction between reliability and resource utilization
Solution Approach 2:
The patent changes system parameters (FEC code rate, block length) according to the number of simultaneous users. By adjusting these parameters dynamically rather than fixing them for worst-case scenarios, the system achieves both reliable communication and efficient resource utilization across different loading conditions
2Reliability
If system parameters are optimized for single user scenario, then communication performance is improved, but adaptability to varying user loads deteriorates
Solution Approach 1:
The patent makes the FEC coding parameters dynamic by linking them to the number of simultaneous users. This allows the system to maintain optimal communication performance across different user scenarios rather than being fixed for single-user optimization
Solution Approach 2:
The patent creates a universal FEC coding scheme that can adapt to multiple user scenarios (single user, multiple users, varying loads) through parameter adjustment. The same base code structure serves multiple functions across different operating conditions
3Quantity of substance
If FEC codes are optimized for high user loads, then system capacity is improved, but performance under light loading conditions deteriorates
Solution Approach 1:
The patent adjusts FEC parameters (code rate, block length) based on user load conditions. For light loading, more aggressive error correction is applied; for heavy loading, parameters are adjusted to maximize capacity, achieving optimal performance across all load conditions
Data Source
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AI summary
Various methods and apparatuses are disclosed, including a method for optimizing FEC code for an average number of interfering users in a multiple access communication, that includes receiving an FEC code optimization information, switchable between at least a first value and a second value, and selecting a first optimized FEC code based at least in part on the FEC code selection information being at the first value, and selecting a second optimized FEC code based at least in part on the FEC code selection information being at the second value. The method can include receiving a source bit stream, encoding bits of the source bit stream according to the selected optimized FEC code into a series of FEC encoded bits, and a parity check matrix of the first optimized FEC code has a first average information bit node degree, and a parity check matrix of the second optimized FEC code has a second average information bit node degree.