PRACH Preamble Time-of-Arrival Determination Using Beam-Weighted Hypothesis Testing
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Solution Overview
Problem
Existing hypothesis testing methods for determining the time-of-arrival of a PRACH preamble in large cells with high frequency bands are cumbersome and inefficient, particularly when the round-trip time exceeds the period of the Zadoff-Chu sequence.
Innovation Solution
A method for determining the time-of-arrival of a PRACH preamble using hypothesis testing that incorporates a weight factor value dependent on beam information, allowing for more accurate estimation of the time-of-arrival in large cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hypothesis testing methods are used to determine time-of-arrival when round-trip time exceeds Zadoff-Chu sequence period, then time-of-arrival can be determined for large cells, but the method becomes cumbersome and inefficient
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing weight factor values for different beam information scenarios before actual time-of-arrival determination. During operation, the appropriate weight factor is directly retrieved and applied, avoiding complex real-time calculations. This prepares the system in advance with pre-computed parameters that simplify the actual measurement process.
Solution Approach 2:
The patent changes parameters by introducing beam information as an additional parameter that influences the weight factor selection. Instead of using a single fixed hypothesis testing approach, the system adapts the weight factor based on beam-specific parameters, allowing the hypothesis testing to be tailored to specific propagation conditions and improving efficiency for different cell scenarios.
2Productivity
If beam information is incorporated into hypothesis testing with weight factor values, then time-of-arrival determination efficiency is improved, but computation complexity increases
Solution Approach 1:
The patent pre-computes weight factor values for various beam information scenarios and stores them for direct retrieval during operation. This preliminary preparation eliminates the need for complex real-time computations, as the system simply selects the appropriate pre-calculated weight factor based on the observed beam information, thereby improving efficiency without adding computational burden during actual time-of-arrival determination.
Solution Approach 2:
The patent creates copies of weight factor values for different beam conditions and stores them in lookup tables. Instead of performing complex calculations during operation, the system copies and applies the appropriate pre-stored weight factor that matches the observed beam information, significantly reducing computation complexity while maintaining determination efficiency.
Data Source
AI summary
There is provided mechanisms for determining time-of-arrival of a PRACH preamble. A method is performed by a radio access network node. The radio access network node is configured for beamformed communication in a set of beams. The method comprises receiving, from a UE and at a TRP of the radio access network node, a PRACH preamble. The method comprises determining a weight factor value for the PRACH preamble. The weight factor value is dependent on beam information mapped to the PRACH preamble. The beam information identifies one of the beams in the set of beams. The method comprises determining time-of-arrival of the PRACH preamble using hypothesis testing that incorporates the weight factor value.