PRACH Preamble Detection Using Symbol Combining for Coverage Extension
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Solution Overview
Problem
The challenge of reducing the coverage of base stations in mobile communication systems due to the use of higher frequency bands, which limits signal transmission distance and increases the need for additional base stations, especially in sparsely populated areas, without modifying the established standard specifications.
Innovation Solution
A method and apparatus for detecting a preamble signal of a random access channel in a base station using a preamble symbol unit data generator, fast Fourier transformer, sequence generator, coverage extension detector, and delay ambiguity detector to extend coverage without altering the standard specification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher frequency bands are used for mobile communication, then data communication capability is improved, but signal transmission distance is reduced
Solution Approach 1:
The patent combines multiple preamble symbols (first preamble symbol and second preamble symbol) into a single detection unit. By merging these symbols and performing joint detection, the system accumulates signal energy over multiple symbols, thereby extending the effective transmission distance and coverage area without changing the frequency band.
2Area of stationary object
If the number of base stations is increased to extend coverage, then coverage area is improved, but infrastructure cost increases
Solution Approach 1:
The patent dynamically adjusts the detection window to include multiple preamble symbols that may arrive at different times. This dynamic detection approach allows the base station to effectively receive signals from farther distances, thereby extending coverage area without requiring additional base stations.
3Area of stationary object
If standard specification is modified to extend PRACH coverage, then coverage is improved, but system complexity increases
Solution Approach 1:
The patent performs detection on a partial set of preamble symbols (specifically, the first and second preamble symbols) rather than requiring complete modification of the entire PRACH structure. This partial action approach extends coverage while maintaining most of the existing standard specification, thereby limiting the increase in system complexity.
Data Source
AI summary
A preamble reception apparatus and a reception method for extending a range of a base station are provided. The apparatus includes a preamble symbol unit data generator for receiving preamble symbols, a first fast Fourier transformer for fast Fourier transforming each output of the preamble symbol unit data generator, a first sequence generator for generating a preamble sequence, a coverage extension detector configured to calculate symbol power of each of the preamble symbols, calculate a non-coherent sum for each consecutive preamble symbol, combine the non-coherent sums, and detect a maximum energy value among the non-coherent sums and a first delay value (DF) of the preamble symbols having the maximum energy value, a delay ambiguity detector configured to calculate power for two consecutive preamble symbols, and estimate a second delay value (DT) of the preamble symbols, and a preamble determiner for determining whether a preamble is received.