PDSCH Scheduling with DFT-s-OFDM for High-Frequency 5G
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining the single carrier property for downlink transmission above 52.6GHz carrier frequency, particularly when using DFT-s-OFDM waveform, which affects resource allocation and multiplexing of physical downlink shared channels (PDSCHs) and physical downlink control channels (PDCCHs).
Innovation Solution
The proposed solution involves a scheduling mechanism for PDSCH with DFT-s-OFDM waveform, including resource allocation, PT-RS design, and multiplexing of PDSCH and PDCCH in a time division multiplexing (TDM) manner prior to the DFT operation. This ensures that multiple PDSCHs from the same or different UEs are multiplexed in a TDM manner, with a same DFT size applied for transmission, and demodulation reference signals (DMRS) are multiplexed with PDSCH in a TDM manner as well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If DFT-s-OFDM waveform is used for downlink transmission above 52.6GHz, then single carrier property is maintained, but resource allocation and multiplexing of PDSCH and PDCCH becomes complex
Solution Approach 1:
The resource allocation is segmented into distinct time-domain regions: PDCCH occupies the first OFDM symbol while PDSCH occupies subsequent symbols within the same slot. This segmentation allows separate handling of control and data channels while maintaining single carrier property through unified DFT-s-OFDM waveform
Solution Approach 2:
The patent introduces a new dimension for resource allocation by applying TDM within the time domain of a single slot, rather than using traditional FDM or spatial multiplexing. This temporal dimension approach simplifies the multiplexing mechanism while preserving single carrier characteristics
2Stability of the object's composition
If multiple PDSCHs are multiplexed in TDM manner with same DFT size, then single carrier property is preserved, but resource allocation flexibility is reduced
Solution Approach 1:
The system dynamically adapts the DFT size based on the number of multiplexed PDSCHs and available resources. While a same DFT size is applied within each transmission for single carrier property, the DFT size itself can be adjusted across different transmissions to optimize resource utilization and adapt to varying traffic conditions
Solution Approach 2:
The patent changes the DFT size parameter to balance between maintaining single carrier property and providing resource allocation flexibility. By adjusting the DFT size according to the number of multiplexed PDSCHs and channel conditions, the system achieves both goals
3Stability of the object's composition
If PDSCH and PDCCH are multiplexed in TDM manner, then single carrier property is maintained, but transmission efficiency is reduced due to sequential transmission
Solution Approach 1:
PDCCH is transmitted in the first OFDM symbol as a preliminary action before PDSCH transmission. This preliminary control signal transmission enables subsequent PDSCH transmissions to proceed efficiently with pre-configured resource allocation and modulation parameters, minimizing overhead
Data Source
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AI summary
An approach is described for a wireless communication for a fifth generation (5G) or new radio (NR) system. The wireless communication includes a gNode (gNB) configured to indicate a time domain resource allocation within one Discrete Fourier Transform (DFT) size in a downlink control information (DCI), and to transmit a physical downlink shared channel (PDSCH) with a Discrete Fourier Transform-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) waveform in accordance with the time domain resource allocation within the one DFT size.