NOMA Spreading Sequence Configuration for Inter-Cell Interference Reduction
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Solution Overview
Problem
Current wireless communication technologies, such as LTE and NR, face challenges in reducing inter-cell interference in NOMA communications, which affects throughput and the complexity of modulation schemes, especially in scenarios with cell-edge UEs.
Innovation Solution
The use of multiple sets of spreading sequences, where a first set is assigned to cell-center UEs and a second set to cell-edge UEs, configured to reduce inter-cell interference by employing different codebooks or applying mask sequences, thereby improving radio performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single set of spreading sequences is used for all UEs, then device complexity is reduced, but inter-cell interference increases
Solution Approach 1:
The patent segments the UE population into different groups (cell-center UEs and cell-edge UEs) and assigns different spreading sequence sets to each group. This segmentation allows optimized interference management for different UE locations while maintaining manageable complexity through structured grouping rather than individual UE customization.
Solution Approach 2:
The patent applies local quality by assigning different spreading sequence sets based on UE location within the cell. Cell-center UEs receive one set of sequences while cell-edge UEs receive another set, optimizing the solution locally for each UE's interference characteristics rather than applying a uniform approach.
2Object-affected harmful factors
If multiple sets of spreading sequences are configured for different UE locations, then inter-cell interference is reduced, but configuration complexity increases
Solution Approach 1:
The patent divides the spreading sequence configuration into discrete sets that can be independently managed and assigned. By segmenting sequences into distinct groups for different UE types, the system reduces configuration complexity compared to individual UE customization while still achieving interference reduction.
Solution Approach 2:
The patent utilizes parameter changes by switching between different spreading sequence sets based on UE location. This parameter switching approach allows the system to adapt to different interference conditions without requiring complex continuous adjustment, maintaining manageable configuration complexity.
3Productivity
If cell-edge UEs use the same spreading sequences as cell-center UEs, then device complexity is minimized, but throughput is reduced due to interference
Solution Approach 1:
The patent implements local quality by providing cell-edge UEs with dedicated spreading sequence sets that are optimized for their interference-prone locations. This localized optimization enables cell-edge UEs to achieve improved throughput without requiring complex individualized configurations, as the solution is applied uniformly to all cell-edge UEs.
Solution Approach 2:
By segmenting UEs into cell-center and cell-edge groups with separate sequence sets, the patent enables throughput optimization for cell-edge UEs while maintaining configuration simplicity through group-based management rather than individual UE customization.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network controller may determine a first set of spreading sequences and a second set of spreading sequences for non-orthogonal multiple access (NOMA) communication, wherein the first set of spreading sequences is different than the second set of spreading sequences; and configure a first cell to use the first set of spreading sequences and a second cell to use the second set of spreading sequences; or configure the first set of spreading sequences to be used for first user equipment associated with a cell center of the first cell and the second set of spreading sequences to be used for second user equipment associated with a cell edge of the first cell or the second cell. Numerous other aspects are provided.