UE-RS Sequence Initialization Orthogonality in MU-MIMO
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Solution Overview
Problem
In wireless communication systems, especially in MU-MIMO configurations, existing methods for initializing UE-RS sequences are dependent on specific UE identifiers and resource bandwidths, leading to non-orthogonality and interference issues among paired UEs, particularly in multi-cell scenarios.
Innovation Solution
The initialization of UE-RS sequences is made independent of specific UE identifiers and resource bandwidths by using cell-dependent, subframe-dependent, and bandwidth-agnostic approaches, such as initializing based on cell identifiers, resource block identifiers, antenna port indices, and cyclic prefix types, ensuring orthogonality and alignment across UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE-RS sequences are initialized using UE-specific identifiers and resource bandwidths, then the sequences can be customized for each UE, but orthogonality and interference issues arise among paired UEs in MU-MIMO configurations
Solution Approach 1:
The patent extracts the UE-specific identifier dependency from the sequence initialization process. By removing the UE ID from the initialization parameters and using only cell ID, subframe number, and resource block index, the patent eliminates the source of non-orthogonality while preserving the ability to generate UE-specific sequences through resource allocation
Solution Approach 2:
The patent creates a universal sequence initialization method that works for all UEs in the cell regardless of their specific identifiers. The initialization function c_init = f(cell_id, subframe_number, resource_block_index) serves all UEs uniformly, ensuring that sequences assigned to different UEs on the same resource blocks remain orthogonal
2Quantity of substance
If UE-RS sequences are initialized based on UE identifiers, then each UE has unique sequences, but alignment and orthogonality problems occur in multi-cell MU-MIMO scenarios
Solution Approach 1:
The patent applies local quality by making sequences unique to specific resource allocations rather than to UEs. The sequence initialization depends on the local resource context (resource block index, subframe number) rather than global UE identity, ensuring that sequences are locally unique for each resource assignment while maintaining orthogonality across UEs sharing the same resources
Solution Approach 2:
The patent creates equipotential conditions by ensuring all UEs in the system use the same initialization function with the same parameters (cell_id, subframe_number, resource_block_index). This uniform approach ensures that sequences from different cells and different UEs maintain consistent orthogonality relationships
3Adaptability or versatility
If UE-RS sequences depend on resource bandwidth assignments, then sequences adapt to UE allocations, but interference occurs when UEs have different bandwidth assignments
Solution Approach 1:
The patent transitions from a one-dimensional UE-specific sequence assignment to a multi-dimensional resource-based assignment. By incorporating resource block index and subframe number as initialization parameters, the patent creates sequences that are unique across multiple dimensions (frequency, time, and resource allocation), allowing UEs with different bandwidth assignments to maintain orthogonality
Data Source
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AI summary
Pseudo-random sequences of a plurality of user equipment specific reference signals (UE-RSs) for use by a plurality of user equipments (UEs) are initialized, the initialization of each pseudo-random sequence associated with each UE-RS being independent of a specific UE identifier and independent of a resource bandwidth assigned to a specific UE. Pseudo-random sequences of the UE-RSs are generated. At least one of the pseudo-random sequences is mapped to a portion of common resources for at least one UE among the plurality of UEs.