Digital Beamforming With Short Repetitive Sync Sequences
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Solution Overview
Problem
Existing digital beamforming techniques for multi-element array antennas struggle with accurate signal estimation in noise and jamming environments when using short repetitive synchronization sequences, as they provide poor estimates due to limited sequence lengths and hardware constraints.
Innovation Solution
The method involves calculating relative phases and cross correlation vectors for each element of the multi-element array antenna, converting them into relative phase arrays, and generating a relative cross correlation vector estimate to improve signal estimation and interference reduction, enabling effective digital beamforming even with short synchronization sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If many samples are used when calculating cross correlation vector and covariance matrix, then measurement precision is improved, but device complexity increases due to hardware processing and memory constraints
Solution Approach 1:
The patent segments the long sequence into multiple shorter subsequences and processes them separately. Each subsequence is correlated with the known sequence independently, and the results are combined to form the final cross correlation vector estimate. This segmentation allows accurate estimation without requiring the full long sequence to be processed at once, reducing memory and processing constraints.
Solution Approach 2:
The patent performs preliminary processing by pre-calculating and storing the known sequence and its properties before receiving the actual signal. This preliminary preparation allows the receiver to efficiently process incoming short subsequences without requiring extensive real-time computation, reducing the processing burden during actual operation.
2Productivity
If short synchronization sequences are used, then productivity is improved, but measurement precision deteriorates due to poor correlation output estimates
Solution Approach 1:
The patent merges multiple correlation outputs from different short subsequences to form a single, more accurate cross correlation vector estimate. By combining the results from multiple independent correlations, the patent achieves estimation accuracy comparable to processing a single long sequence, while maintaining the productivity benefits of using short sequences.
Solution Approach 2:
The patent employs periodic correlation operations on repeatedly received short synchronization sequences. Each reception of the short sequence triggers a correlation operation, and these periodic operations accumulate evidence that improves the overall estimate accuracy over time, bridging the gap between short sequence usage and accurate measurement.
3Ease of operation
If standard DBF algorithms are used with short sequences, then ease of operation is maintained, but reliability deteriorates in noise and jamming environments
Solution Approach 1:
The patent introduces an intermediary processing stage between receiving short sequences and performing DBF algorithms. This intermediary stage computes enhanced cross correlation vector estimates by combining multiple correlations, serving as a mediator that improves reliability without complicating the overall system operation or requiring changes to standard DBF algorithms.
Data Source
AI summary
A system and method of enabling digital beamforming (DBF) for use with RF receiver systems with a multi-element array antenna having short repetitive synchronizaton sequences in a noise and/or jamming environment. The method includes the following steps: a) receiving repetitive synchronization RF signals utilizing a multi-element array antenna, each of the repetitive synchronization RF signals includes an ideal known synchronization sequence, the ideal known synchronization sequence is denoted as yd and a length of the ideal known synchronization sequence is denoted as Nd; b) calculating a sequence of magnitudes and phases for each element of the multi-element array antenna corresponding to each of the ideal known synchronization sequences in the received synchronization RF signals, the sequence of the magnitudes and the phases comprises an array of N elements and is denoted as x, wherein the phases are also referred to as absolute phases; c) calculating a relative phase for each element in the sequence of the magnitudes and the absolute phases by referencing the absolute phases of all elements in the array x of N elements to a phase of a single element in the array x of N elements; d) converting the array x of N elements with the magnitudes and the absolute phases into an array of N elements with the magnitudes and the relative phases by replacing each of the absolute phases in the array x of N elements with the calculated relative phase for each element, the array of N elements with the magnitudes and the relative phases is denoted as xr; e) calculating a relative cross correlation vector for each element of the multi-element array antenna utilizing xr and yd, the relative cross correlation vector is denoted as rxd, where rxd=E{xryd*} and * is a complex conjugate; and, f) generating a relative cross correlation vector estimate by filtering rxd, for use with DBF techniques.