Interlaced DFT-S PUCCH User Multiplexing Under PSD Constraints
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently multiplexing multiple users in frequency spectra due to PSD requirements, which limit the number of users that can be frequency-multiplexed, especially when transmitting at full power.
Innovation Solution
Implementing DFT precoded frequency interlaces with orthogonal block-spreading codes to assign different UEs on the same frequency interlace, applying block-spreading and DFT precoding to spread information symbols across resource blocks, and performing time-domain spreading and code-hopping to enhance user multiplexing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency occupancy is spread over a wider bandwidth to meet PSD requirements, then power spectral density compliance is improved, but the number of users that can be frequency-multiplexed decreases
Solution Approach 1:
The frequency spectrum is segmented into multiple frequency interlaces, where each interlace consists of non-contiguous resource blocks. This segmentation allows users to be multiplexed across different interlaces while maintaining PSD compliance within each interlace, thereby resolving the contradiction between PSD requirements and user multiplexing capacity.
Solution Approach 2:
The patent introduces a new dimension for user multiplexing by combining frequency interlace domain with code domain. Block-spreading codes are applied in the code domain to spread user signals across resource blocks within the same frequency interlace, enabling multiple users to share the same frequency resources without interfering with each other, thus increasing multiplexing capacity while maintaining PSD compliance.
2Quantity of substance
If block-spreading codes are applied to spread information symbols across resource blocks, then user multiplexing capacity is improved, but signal complexity increases
Solution Approach 1:
Block-spreading codes are pre-defined and assigned to different users before transmission. The spreading operation is performed as a preliminary step before DFT precoding, which simplifies the overall processing chain. The receiver can similarly apply preliminary despreading operations to separate user signals, reducing the complexity of signal separation.
Solution Approach 2:
The block-spreading codes act as an intermediary mechanism between the information symbols and the frequency interlace resources. These codes provide a structured way to map user data to resource blocks, enabling systematic user separation at the receiver while maintaining manageable processing complexity through the use of orthogonal or near-orthogonal code structures.
Data Source
AI summary
Wireless communications systems and methods related user multiplexing with discrete Fourier transform (DFT) precoded frequency interlaces are provided. A first wireless communication device identifies a first block-spreading code from a set of block-spreading codes associated with user multiplexing. The first wireless communication device communicates, with a second wireless communication device using a frequency interlace in a frequency spectrum, a first communication signal including a first block of information symbols spread across a set of resource blocks (RBs) within the frequency interlace based on the first block-spreading code. The first communication signal is generated by block-spreading the first block of information symbols based on the first block-spreading code to produce a first block of spread information symbols, performing a DFT on the first block of spread information symbols, and mapping the first block of spread information symbols to the set of RBs.