Uplink Reference Signal Extension for Odd Resource Block Mapping
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Solution Overview
Problem
Existing wireless communication technologies face challenges in maintaining orthogonality of reference signal sequences when using spectral extension, leading to increased interference and inefficiency in resource allocation, particularly when odd numbers of resource blocks are allocated in the spectrally extended frequency band.
Innovation Solution
The proposed solution involves applying a frequency shift and cyclic extension to the reference signal sequence, either symmetrically or asymmetrically, based on the number of resource blocks inside and outside the frequency interval, to maintain orthogonality and reduce spectral shaping overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spectral extension is applied to widen frequency extent, then spectral efficiency is improved, but reference signal sequence orthogonality deteriorates
Solution Approach 1:
The patent applies asymmetric cyclic extension to the reference signal sequence, where the extension length at the first end differs from the extension length at the second end. This asymmetric approach allows the sequence to accommodate odd numbers of resource blocks in spectrally extended bands while maintaining orthogonality properties, resolving the contradiction between spectral efficiency improvement and reference signal orthogonality preservation.
Solution Approach 2:
The patent modifies the reference signal sequence parameters by applying cyclic shifts and asymmetric cyclic extensions based on the number of resource blocks allocated in different frequency intervals. This parameter change enables the reference signal to adapt to various spectral extension configurations, maintaining orthogonality while achieving improved spectral efficiency.
2Productivity
If frequency shift is applied to handle odd resource blocks, then resource allocation efficiency is improved, but sequence mapping complexity increases
Solution Approach 1:
The patent segments the frequency band into different intervals (first frequency interval and second frequency interval) and applies different reference signal sequence extension strategies to each segment. This segmentation allows efficient handling of odd resource block allocations in spectrally extended bands while managing complexity through structured, interval-based processing.
Solution Approach 2:
The patent performs preliminary cyclic extension and cyclic shift operations on the reference signal sequence before mapping it to the resource blocks. This preliminary action prepares the sequence in advance for the frequency shift and resource allocation process, improving resource allocation efficiency while keeping the overall mapping process systematic and manageable.
Data Source
AI summary
According to an example aspect of the present invention, there is provided an apparatus configured to select a reference signal sequence, determine a number of resource blocks located outside a frequency interval via spectrally extending the signal, and when the number is an odd number, perform exactly one of the following: symmetrically extend a cyclically shifted version of the selected reference signal sequence, or asymmetrically extend the selected reference signal sequence without shifting it, map the extended reference signal sequence to resource blocks located in the frequency interval and resource blocks located outside the frequency interval, perform spectral shaping of a second signal comprising the resource blocks located both inside and outside the frequency interval, and transmit the second signal in uplink direction.