DFT-Spread PDCCH Code Multiplexing for High-Frequency PA Efficiency
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Solution Overview
Problem
Power amplifiers (PAs) in wireless transmit/receive units (WTRUs) exhibit lower efficiency and saturated power at higher frequencies, especially above 100 GHz, particularly for signals with high peak to average power ratio (PAPR), necessitating a solution for improved power and coverage efficiency in beyond 5G NR downlink operations.
Innovation Solution
A WTRU configuration for discrete Fourier Transform (DFT)-spread orthogonal frequency division multiplexing (DFT-s-OFDM) that includes determining resource groups (RGs) and orthogonal cover codes (OCCs) based on network configurations, with code domain multiplexing and dynamic adaptation for efficient PDCCH decoding, enabling channel frequency-selective diversity processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If DFT-s-OFDM waveform is adopted for downlink at high frequencies, then power amplifier efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments the control channel resources into multiple resource groups (RGs) that can be independently configured and processed. Each RG can be associated with different orthogonal cover codes (OCCs) and spreading factors, allowing the system to divide the complex PDCCH decoding task into manageable segments while maintaining the power efficiency benefits of DFT-s-OFDM
Solution Approach 2:
The patent introduces dynamic configuration parameters including variable spreading factors (SF), configurable resource group sizes, and adaptive orthogonal code lengths. These dynamic parameters allow the system to optimize the balance between power amplifier efficiency and device complexity based on specific operational conditions, frequency bands, and signal characteristics
2Quantity of substance
If code domain multiplexing is implemented for PDCCH, then resource utilization is improved, but measurement precision deteriorates
Solution Approach 1:
The patent applies local quality by assigning different orthogonal cover codes (OCCs) to different resource groups within the control channel. Each RG can have locally optimized code properties and spreading factors tailored to its specific channel conditions and resource allocation, thereby maintaining decoding accuracy while improving overall resource utilization through code domain multiplexing
3Reliability
If spreading factor is increased for PDCCH, then reliability is improved, but productivity decreases
Solution Approach 1:
The patent implements partial action by applying spreading selectively to different resource groups rather than uniformly across the entire control channel. The spreading factor can be configured differently for each RG, allowing the system to apply enhanced spreading (higher reliability) only where needed while maintaining faster decoding (higher productivity) in other regions with less stringent requirements
Data Source
AI summary
A wireless transmit/receive unit (WTRU) is configured to report to a network the WTRU capability for physical downlink control channel (PDCCH) decoding including supported number of discrete fourier transform (DFT) modules and sizes and receive from the network a PDCCH configuration as a search space and control resource set (CORESET) configurations having a spreading factor or an orthogonal code length, a number of frequency resource groups (FRGs) and associated sizes, an indication of code domain multiplexing, and a CORESET format. The WTRU determines resource groups (RG) size and a number of RGs per control channel elements (CCE) based on configured spreading factor and FRG size, and determines an association between RGs and orthogonal cover codes (OCCs) per FRG and orthogonal frequency division multiplexing (OFDM) symbol based on, among other things, the configured spreading factor.