Fragmented Downlink Carrier Combining for UE Bandwidth Limits
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Solution Overview
Problem
User equipment (UE) processing circuitry faces challenges in handling fragmented spectrum blocks due to hardware limitations when the total bandwidth of carriers exceeds a threshold, including issues with in-gap blocking and exceeding maximum carrier bandwidth, which current 5G standards do not support.
Innovation Solution
The UE employs an analog signal path with frequency down-conversion mixers, tunable complex bandpass IF filters, and ADCs to shift and combine fragmented carriers, reducing the total bandwidth to below the threshold by eliminating frequency gaps and in-gap blockers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE processes multiple fragmented spectrum blocks separately through digital front end, then each spectrum block can be handled independently, but the hardware complexity and processing requirements increase significantly
Solution Approach 1:
The patent combines multiple fragmented spectrum blocks into a single aggregated carrier by mapping resource blocks from different frequency locations to contiguous resource blocks in the frequency domain. This merging approach allows the UE to process multiple spectrum blocks as one unified carrier, reducing hardware complexity while maintaining the ability to handle fragmented spectra. The resource block mapping function reindexes resource blocks such that RBs from different component carriers are mapped to contiguous indices in the aggregated carrier.
2Quantity of substance
If the total bandwidth of fragmented carriers exceeds the threshold, then more spectrum resources can be utilized, but the UE's processing circuitry cannot handle the signal due to hardware limitations
Solution Approach 1:
The patent transforms the problem from the frequency domain to a resource block index domain through a mapping function. By reindexing resource blocks from multiple fragmented carriers into a contiguous sequence of indices, the system effectively changes the dimensional representation of the spectrum. This allows the UE to process large total bandwidths by mapping them to a unified resource grid that fits within hardware processing limits, while still utilizing the full aggregated bandwidth for data transmission.
3Object-affected harmful factors
If frequency gaps exist between fragmented carriers, then interference between carriers is reduced, but the total bandwidth utilization decreases and processing becomes more complex
Solution Approach 1:
The patent extracts and removes the frequency gap information from the resource block mapping process. By reindexing resource blocks such that RBs from different component carriers are mapped to contiguous indices without preserving the original frequency gaps, the system eliminates the impact of gaps on bandwidth utilization. The mapping function takes out the gap structure and creates a dense, contiguous resource allocation in the aggregated carrier, maximizing bandwidth usage while the physical frequency separation remains for interference reduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the UE to process fragmented carriers as a single carrier within the supported bandwidth limits, ensuring accurate signal demodulation and reducing hardware complexity.
Implementation Method 1
The UE employs an analog signal path with frequency down-conversion mixers, tunable complex bandpass IF filters, and ADCs to shift and combine fragmented carriers
Data Source
AI summary
Techniques for described for combining fragmented carriers. An example method can include processing, using a first local oscillator (LO), a first analog signal and a second analog signal that are separated by a frequency offset, an output of the first LO used to generate a first digital signal and a second digital signal. The method can further include downshifting the first digital signal based on the center frequency to generate a downshifted digital signal. The method can further include upshifting the second digital signal based on the center frequency to generate an upshifted digital signal. The method can further include combining the downshifted signal and the upshifted signal to generate a combined digital signal, wherein the downshifted digital signal is orthogonal to the upshifted digital signal, and wherein a second total bandwidth of the combined digital signal is less than the threshold bandwidth.