Adaptive LDPC FEC Selection for Variable NOMA User Interference
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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 and not effectively adaptable 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 bit node degrees that are selected based on the target average number of simultaneous users, allowing for dynamic adaptation of FEC codes in response to changing interference statistics, enabling efficient multi-user simultaneous asynchronous communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If system parameters are fixed for worst-case scenario design, then reliability is improved, but adaptability deteriorates
Solution Approach 1:
The patent implements dynamic selection of FEC code parameters (specifically LDPC code rate and block length) based on the detected number of active users. The system transitions from fixed worst-case parameters to adaptive parameters that change with system conditions, resolving the contradiction between reliability and adaptability by making the system flexible while maintaining performance guarantees.
Solution Approach 2:
The patent changes key system parameters (FEC code rate, block length) according to the number of simultaneous users. By adjusting these parameters dynamically, the system achieves both high reliability through appropriate error correction and adaptability to varying user loads, directly resolving the technical contradiction.
2Reliability
If system resources are allocated for worst-case scenario, then reliability is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts resource allocation (FEC overhead, code rate) based on actual user load conditions. During light loading, fewer resources are allocated to error correction, improving efficiency. During heavy loading, more resources are allocated to maintain reliability, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent changes FEC parameters (code rate, block length) according to user load, optimizing the balance between reliability and resource utilization efficiency. This parameter adaptation allows the system to achieve high reliability when needed while maximizing resource efficiency during normal operation.
3Reliability
If FEC codes are optimized for single user scenario, then communication performance is improved, but multi-user performance deteriorates
Solution Approach 1:
The patent implements dynamic FEC code selection that adapts to the number of active users. The system maintains single-user optimized performance when one user is active and transitions to multi-user optimized performance when multiple users are present, resolving the contradiction between single-user and multi-user performance optimization.
Solution Approach 2:
The patent changes FEC code parameters based on user scenario (single-user vs. multi-user conditions), allowing the system to achieve optimal communication performance for each scenario. This adaptive parameter selection resolves the contradiction by providing scenario-specific optimization rather than a single fixed configuration.
Data Source
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.