DFT-S-OFDM and CP-OFDM Dynamic Switching via MAC Control
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Solution Overview
Problem
Current 5G NR systems lack dynamic switching between DFT-S-OFDM and CP-OFDM waveforms, leading to high latency and link interruption during RRC reconfiguration, especially for high-speed UEs moving between cell centers and edges.
Innovation Solution
Implement dynamic switching by using Medium Access Control (MAC) layer communication messages (MAC CE) or Downlink Control Information (DCI) to change between DFT-S-OFDM and CP-OFDM waveforms, reducing latency and link interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If RRC reconfiguration is used to switch between DFT-S-OFDM and CP-OFDM waveforms, then the waveform switching can be performed, but the latency increases and link interruption occurs
Solution Approach 1:
The patent applies dynamics by enabling flexible switching between DFT-S-OFDM and CP-OFDM waveforms based on real-time UE location and channel conditions. The system transitions from static RRC reconfiguration to dynamic MAC CE-based switching, allowing the waveform to be adapted dynamically as UEs move between cell center and edge, thereby reducing latency and avoiding link interruption.
Solution Approach 2:
The patent changes the control parameter from RRC layer configuration to MAC CE layer control. By modifying the waveform type parameter through MAC CE messages rather than requiring full RRC reconfiguration, the system achieves faster switching with minimal latency and without causing link interruption, directly addressing the technical contradiction.
2Productivity
If RRC reconfiguration message is used for waveform switching, then the network can control the waveform change, but the processing complexity and latency increase
Solution Approach 1:
The patent extracts the waveform switching function from the complex RRC layer processing and implements it at the MAC CE layer. This extraction simplifies the control mechanism by removing unnecessary RRC layer involvement, enabling faster switching decisions and reducing processing complexity while maintaining network control capability.
Solution Approach 2:
The system introduces dynamic switching capability at the MAC CE layer, allowing rapid waveform changes without the rigid RRC reconfiguration process. This dynamic approach enables the network to respond quickly to changing conditions and improve switching speed while reducing the complexity associated with full RRC layer processing.
3Adaptability or versatility
If static waveform configuration is used, then the network configuration is simple, but the adaptability to UE movement between cell center and edge is poor
Solution Approach 1:
The patent implements dynamic waveform adaptation by enabling the gNB to switch between DFT-S-OFDM and CP-OFDM based on real-time UE location and channel conditions. This dynamic mechanism allows the system to adapt to UE movement between cell center and edge, improving versatility while managing complexity through standardized MAC CE-based control.
Solution Approach 2:
The system changes the configuration parameter from static RRC layer settings to dynamic MAC CE layer control. This parameter change enables flexible waveform adaptation to varying UE conditions and locations, improving versatility while maintaining manageable complexity through the established MAC CE framework.
Data Source
AI summary
There is provided a method of switching between Discrete Fourier Transform spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) and Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) in a mobile communication system. The method is performed by a g NodeB (gNB), and includes (a) preparing a Medium Access Control (MAC) layer communication message that specifies which of DFT-S-OFDM or CP-OFDM will be used for an uplink (UL) waveform, and (b) dynamically transmitting the message to user equipment. There is also provided an apparatus that performs the method, and a storage device that contains instructions that cause a processor to perform the method.