Unified UL/DL Waveform Layout for 5G Interference Cancellation
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Solution Overview
Problem
Existing wireless communication technologies have not effectively addressed the diverse performance requirements of 5G wireless networks, particularly in managing interference and optimizing downlink and uplink transmissions to support various services and applications with varying latency and spectral efficiency needs.
Innovation Solution
Implementing a symmetric downlink and uplink design in 5G systems using a unified waveform for both uplink and downlink transmissions, combined with hybrid DM-RS patterns and a hybrid mode for uplink transmission that switches between SC-FDMA and OFDMA based on coverage needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate waveform designs are used for downlink and uplink transmissions, then each direction can be optimized independently, but receiver design becomes more complex and interference cancellation is less effective
Solution Approach 1:
The patent merges the downlink and uplink waveform designs by using the same OFDM-based waveform for both directions. This unification allows the receiver to use identical processing algorithms for both downlink and uplink signals, significantly reducing receiver design complexity while improving interference cancellation effectiveness through consistent waveform characteristics.
Solution Approach 2:
The patent creates a universal waveform design that serves both downlink and uplink transmissions. The same OFDM waveform structure, reference signal patterns, and processing techniques are applied universally to both transmission directions, eliminating the need for separate optimization and reducing overall system complexity.
2Device complexity
If a unified waveform is used for both uplink and downlink, then receiver design is simplified and interference cancellation is enhanced, but flexibility in optimizing for specific service requirements is reduced
Solution Approach 1:
The patent introduces dynamic adaptability within the unified OFDM waveform framework by allowing flexible configuration of parameters such as subcarrier spacing, cyclic prefix length, and resource allocation patterns. This enables the system to adapt to different service requirements (e.g., eMBB, uRLLC, mMTC) while maintaining the benefits of a unified waveform design.
Solution Approach 2:
The patent achieves service-specific optimization by changing key waveform parameters such as subcarrier spacing, symbol duration, and resource block allocation within the unified OFDM structure. These parameter adjustments allow the system to meet diverse service requirements without abandoning the unified waveform approach.
3Loss of time
If hybrid ARQ round trip time is reduced to meet latency requirements, then control signaling latency is improved, but the system requires more frequent link direction switching which increases complexity
Solution Approach 1:
The patent prepares for frequent link direction switching by pre-configuring the unified OFDM waveform structure and reference signal patterns to be compatible with both downlink and uplink transmissions. This preliminary preparation allows rapid switching between link directions without requiring complex reconfiguration, thus reducing control signaling latency while managing switching complexity.
Data Source
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AI summary
Technology described herein addresses symmetric uplink (UL) / downlink (DL) designs that can be applied to both uplink and downlink transmissions. A symmetric UL/DL design can define a Transmission Time Interval (TTI) format with control channels and data channels multiplexed using Frequency Division Multiplexing (FDM) or Time Division Multiplexing (TDM) to partition the control channels and the data channels within a Transmission Time Interval (TTI). A unified waveform can be applied to both UL and DL transmissions. Several Demodulation Reference Signal (DM-RS) designs are also described. A hybrid mode for UL transmissions is also described.