PRB Bundle Alignment in 5G O-RAN Beamforming
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Solution Overview
Problem
In wireless communications systems, particularly in 5G NR systems with disaggregated base stations, there is a challenge in aligning beamforming weights with physical resource blocks (PRBs) due to misalignment issues between PRB bundles and precoding resource block groups or static beamforming grids, leading to suboptimal beamforming performance.
Innovation Solution
The solution involves signaling parameters such as precoding resource block group size and offset between allocated PRBs and the start of a PRG or PRB bundle from the O-DU to the O-RU, allowing the O-RU to compute and correct misalignment, thereby accurately associating beamforming weights with PRBs, improving overall performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming weights are applied to PRB bundles without alignment correction, then processing is simpler, but beamforming performance deteriorates due to misalignment with logical structures
Solution Approach 1:
The patent applies preliminary action by computing the misalignment offset between PRB bundles and logical structures (PRGs or beamforming grids) before applying beamforming weights. The O-DU calculates this offset and signals it to the O-RU in advance, allowing the O-RU to correctly align beamforming weights with the intended logical structures, thereby resolving the contradiction between simplicity and performance.
2Loss of information
If PRB bundle size is increased to reduce signaling overhead, then signaling efficiency improves, but alignment precision with logical structures deteriorates
Solution Approach 1:
The patent applies parameter changes by introducing a misalignment offset parameter that compensates for the mismatch between PRB bundle boundaries and logical structure boundaries. This parameter is signaled from O-DU to O-RU and used to adjust the application of beamforming weights, allowing larger PRB bundles to be used without sacrificing alignment precision, thus resolving the contradiction between signaling efficiency and alignment precision.
3Productivity
If beamforming weights are applied without misalignment compensation, then processing speed is faster, but transmission reliability deteriorates
Solution Approach 1:
The patent introduces an intermediary parameter (misalignment offset) that mediates between the simple application of beamforming weights and the requirement for precise alignment with logical structures. This offset parameter is calculated by the O-DU and provided to the O-RU, enabling the O-RU to apply beamforming weights with correct alignment without complex real-time processing, thus resolving the contradiction between processing speed and transmission reliability.
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for physical resource block allocation alignment. An example method, performed at a first network entity, includes transmitting beamforming weights (BFWs) to a second network entity, each beamforming weight to be applied to a different bundle of one or more physical resource blocks (PRBs), transmitting, to the second network entity, one or more parameters indicative of a misalignment between an allocation of PRBs and at least one logical structure, and processing signals transmitted between the first and second network entities, with beamforming applied to PRB bundles using the BFWs, in accordance with the one or more parameters.