Uplink Reference Signal Configuration for Non-Contiguous Bandwidth
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Solution Overview
Problem
Current wireless communication systems face challenges in enabling SRS transmissions over non-contiguous bandwidths and efficient orthogonal DMRS multiplexing, particularly in heterogeneous networks and scenarios requiring interference-free channel estimates for MU-MIMO operations.
Innovation Solution
The solution involves configuring DMRS transmission parameters using cyclic shifts and orthogonal covering codes to support SRS bandwidth hopping within parts of a maximum SRS bandwidth and enabling simultaneous SRS transmissions across non-contiguous operating bandwidths, optimizing the use of cyclic shifts and OCCs for orthogonal DMRS multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SRS transmissions are enabled over non-contiguous bandwidths, then spectral efficiency is improved, but device complexity increases
Solution Approach 1:
The SRS transmission bandwidth is segmented into multiple non-contiguous bandwidth parts. The UE is configured with separate bandwidth indicators that specify which segments to transmit on, allowing flexible non-contiguous bandwidth utilization without requiring the device to handle the entire contiguous bandwidth simultaneously, thus improving spectral efficiency while managing complexity through modular configuration
Solution Approach 2:
The SRS transmission configuration is made dynamic through RRC signaling that can adjust bandwidth indicators, hopping patterns, and resource allocations based on network conditions. This dynamic adaptability allows the system to optimize spectral efficiency in real-time while the UE implements complex hopping patterns and bandwidth selections that are dynamically determined rather than fixed
2Measurement precision
If orthogonal DMRS multiplexing is optimized using cyclic shifts and OCCs, then channel estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the form of cyclic shifts and orthogonal covering codes (OCCs) to generate orthogonal DMRS sequences. By varying these parameters across different UEs and time-frequency resources, the system achieves improved channel estimation accuracy through orthogonal separation while the complexity is managed through standardized mathematical transformations rather than custom complex algorithms
Solution Approach 2:
The DMRS configuration framework is designed to be universal, supporting multiple UEs with different cyclic shifts and OCC lengths through a unified RRC configuration mechanism. This multi-functional approach allows the same basic DMRS structure to serve multiple purposes (orthogonal multiplexing, channel estimation, interference reduction) across different UEs and scenarios, improving accuracy without proportionally increasing individual UE complexity
3Object-generated harmful factors
If SRS bandwidth hopping is restricted to parts of maximum SRS bandwidth, then interference reduction is achieved, but adaptability decreases
Solution Approach 1:
The patent applies local quality by restricting SRS bandwidth hopping to specific parts or subsets of the maximum SRS bandwidth based on network conditions and interference patterns. Instead of uniform hopping across the entire bandwidth, the configuration allows selective hopping in specific frequency regions where interference is lower, achieving interference reduction while maintaining adaptability through flexible configuration of which parts to hop in
Solution Approach 2:
The SRS bandwidth hopping configuration is made dynamic through RRC signaling that can adjust the hopping pattern, bandwidth indicators, and restricted regions based on changing network conditions. This dynamic approach allows the system to adapt to different interference scenarios by modifying which parts of the bandwidth are used for hopping, maintaining versatility while achieving interference reduction in specific locations
Data Source
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AI summary
The invention provides a user equipment (UE) for transmitting a physical uplink shared channel (PUSCH) and a demodulation (DM) reference signal (RS) associated with transmission of the PUSCH in a communication system, the UE comprising: a receiver configured to receive a downlink control information (DCI) including a plurality of information elements (IEs) over physical downlink control channel (PDCCH) based on a UE identifier (ID) corresponding to the UE, where the plurality of IEs include a resource allocation (RA) and information indicating a combination of a cyclic shift (CS) for the DM RS and an orthogonal cover code (OCC), and identify the CS for the DM RS and the OCC using the information indicating the combination of the CS for the DM RS and the OCC; and a controller configured to acquire a DM RS sequence based on the identified CS, the identified OCC, and a constant amplitude zero auto-correlation (CAZAC)-based sequence, controlling an inverse fourier transform (IFT) operation performed based on the DM RS sequence and the RA to generate the DMRS, and control a transmitter configured to transmit the DMRS associated with the PUSCH. The invention further provides a base station (BS) and methods to operate the UE and BS.