Hybrid Beamforming and Dynamic TTI Frame Structure
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Solution Overview
Problem
Current wireless communication systems, particularly in new radio access technologies (RAT), face challenges in efficiently configuring frame structures to support diverse use cases such as massive machine-type communications (mMTC) and enhanced mobile broadband (eMBB) within the same spectrum, while also addressing limitations in beamforming techniques that restrict frequency selective capabilities and increase costs.
Innovation Solution
A method and apparatus for configuring a frame structure in wireless communication systems that includes a network node capable of using both legacy and multiple short transmission time intervals (TTIs), allowing for flexible operation and simultaneous support of different use cases by configuring a first frame with one legacy TTI and a second frame with multiple short TTIs, and utilizing hybrid automatic repeat request acknowledgement (HARQ-ACK) operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple antenna elements are installed to increase beamforming gain, then coverage and throughput are improved, but cost increases due to requiring TXRU on each antenna element
Solution Approach 1:
The patent combines digital beamforming (using multiple TXRUs) and analog beamforming (using phase shifters) into a hybrid beamforming system. This merging allows the system to achieve high beamforming gain through digital processing while using analog components to reduce the number of required TXRUs, thereby lowering cost while maintaining performance.
Solution Approach 2:
The patent applies different beamforming approaches to different frequency resources. Digital beamforming is used where frequency selectivity is needed, while analog beamforming is used where it is not required. This local differentiation optimizes the balance between performance and cost by applying the more expensive digital approach only where necessary.
2Ease of manufacture
If analog beamforming is used to reduce cost, then cost is reduced, but frequency selective beaming capability is lost
Solution Approach 1:
The hybrid beamforming system merges digital and analog beamforming capabilities, allowing the system to perform frequency selective beaming when needed (using digital processing on selected antenna subsets) while maintaining cost efficiency (using analog phase shifters for other antenna elements).
Solution Approach 2:
The patent segments the antenna array into multiple subsets, with each subset handled by a separate TXRU. This segmentation allows digital beamforming to be applied selectively to specific antenna groups, providing frequency selective capability without requiring digital processing for all antenna elements, thus balancing adaptability and cost.
3Ease of manufacture
If hybrid beamforming with B TXRUs is used, then cost is reduced compared to full digital beamforming, but the number of simultaneous beam directions is limited to B or less
Solution Approach 1:
The antenna array is divided into B subsets, with each subset connected to one TXRU. This segmentation allows each TXRU to independently control a subset of antenna elements, enabling B simultaneous beam directions. The segmentation approach maximizes the utilization of limited TXRU resources while maintaining spatial diversity and adaptability.
4Device complexity
If a single legacy TTI frame structure is used, then system simplicity is maintained, but flexibility to support diverse use cases (mMTC, eMBB, URLLC) is limited
Solution Approach 1:
The patent introduces dynamic TTI length adaptation, allowing the system to switch between legacy TTI and shortened TTI configurations based on service requirements. This dynamic adjustment enables the same frame structure to support diverse use cases: legacy TTI for eMBB, shortened TTI for URLLC, and configured TTI patterns for mMTC, without requiring fundamentally different frame structures.
Solution Approach 2:
The enhanced frame structure is designed to be universal, capable of supporting multiple use cases through configuration rather than requiring separate dedicated structures. By using parameters such as TTI length, subcarrier spacing, and resource allocation patterns, a single frame structure design can serve eMBB, mMTC, and URLLC requirements.
Data Source
AI summary
A frame structure for a new radio access technology (RAT) is configured by a network node. The network node configures a first frame which has one legacy transmission time interval (TTI) and a second frame which has multiple short TTIs, and communicates with a user equipment (UE) by using at least one of the first frame and the second frame. The UE may be a one of a massive machine-type communication (mMTC) UE, an ultra-reliable and low latency communication (URLLC) UE or an enhanced vehicle-to-everything (eV2X) UE.