5G NR Link Adaptation Algorithm for Memory Reduction
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Solution Overview
Problem
The complexity and memory requirements of link adaptation in 5G NR systems are increased due to the higher number of physical resource blocks compared to LTE, making existing LTE-like approaches inefficient for 5G NR.
Innovation Solution
A new modulation and coding scheme (MCS) and transport block size (TBS) selection algorithm that calculates information bits per resource block group, estimates required resources, and adjusts MCS and TBS based on channel conditions and desired bit transmission, using smaller tables to simplify the process and reduce memory needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LTE-like link adaptation approaches are used in 5G NR, then the system can maintain compatibility with existing protocols, but the complexity and memory requirements increase significantly due to the higher number of physical resource blocks
Solution Approach 1:
The patent segments the link adaptation process by introducing a separate determination step for the number of resource blocks (RBs) independent of the modulation and coding scheme (MCS) selection. This divides the originally coupled two-dimensional table lookup into independent one-dimensional determinations, reducing complexity while maintaining 5G NR compatibility
Solution Approach 2:
The patent transitions from the LTE two-dimensional MCS-TBS table approach to a new dimension by introducing explicit RB count determination as a separate parameter. This dimensional change allows the system to handle 5G NR's larger resource block allocations without requiring exponentially larger lookup tables
2Reliability
If LTE-like large TBS tables are used in 5G NR, then comprehensive transport block size coverage is achieved, but memory requirements become prohibitively large
Solution Approach 1:
The patent segments the transport block size determination into multiple independent steps: first determining the number of RBs, then determining MCS based on spectral efficiency, and finally calculating TBS from these independent parameters. This eliminates the need for storing large two-dimensional tables while maintaining complete TBS coverage
Solution Approach 2:
The patent extracts the RB count determination from the traditional MCS-TBS table lookup process. By explicitly determining RBs as a separate parameter before MCS selection, the system removes the need to store comprehensive two-dimensional mappings, significantly reducing memory requirements
3Productivity
If the number of physical resource blocks is increased for 5G NR, then system capacity and throughput are improved, but the complexity of link adaptation calculations increases
Solution Approach 1:
The patent segments the link adaptation calculation by treating RB count determination as an independent preliminary step before MCS selection. This segmentation allows the system to efficiently handle variable RB allocations in 5G NR without increasing the complexity of the MCS determination process itself
Solution Approach 2:
The patent changes the parameter determination sequence by introducing explicit RB count as a primary parameter determined before MCS selection. This parameter reordering simplifies the calculation complexity by establishing RB allocation independently, allowing the MCS determination to focus only on spectral efficiency considerations
Data Source
AI summary
According to some embodiments, a method for use in a wireless transmitter of a wireless communication network comprises (1) calculating information carrying bits per resource block group (RBG) or physical resource block (PRB) based on a channel condition (e.g., signal to interference plus noise ratio (SINR)); (2) estimating the required information bits and number of RBGs based on the desired number of bits to be transmitted and the number of available RBGs; (3) determining the MCS and TBS based on the estimated information bits, the required number of RBGs, number of layers, and RBG size; (4) adjusting the MCS and TBS based on the MCS index and TBS calculated at step 3, the number of required RBGs, and the accumulated information bits calculated from step 2; and (5) determining an MCS state based on the TBS and the accumulated information bits.