Frequency Division Multiplexing for Mixed TTI User Equipment
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Solution Overview
Problem
Current wireless communication technologies face challenges in efficiently multiplexing communications of user equipment with different transmission time interval (TTI) lengths, particularly in scenarios requiring ultra-reliable low latency communication, where traditional time division multiplexing increases latency and is inefficient in utilizing shared spectrum.
Innovation Solution
Implementing frequency division multiplexing to allocate separate frequency bands for user equipment capable and incapable of using shortened TTIs, synchronizing uplink/downlink TDD patterns across bands to enable concurrent communication while adhering to half-duplex constraints, thereby optimizing spectrum use and meeting stringent latency requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time division multiplexing is used to multiplex communications of user equipment with different TTI lengths, then the system can support both categories of UEs, but latency increases and spectrum utilization becomes inefficient
Solution Approach 1:
The patent transitions from time-domain multiplexing to frequency-domain multiplexing. By introducing frequency as an additional dimension for resource allocation, the system can simultaneously support both shortened TTI and normal TTI UEs without time-based conflicts, thereby reducing latency while maintaining versatility.
Solution Approach 2:
The patent segments the available spectrum into different frequency bands or portions, allocating specific frequency resources to shortened TTI UEs and other frequency resources to normal TTI UEs. This segmentation allows concurrent operations without interference and eliminates the need for time-division multiplexing delays.
2Adaptability or versatility
If time division multiplexing is used to multiplex communications of user equipment with different TTI lengths, then the system can support both categories of UEs, but spectrum utilization becomes inefficient
Solution Approach 1:
By moving from time-based to frequency-based multiplexing, the system utilizes the frequency dimension to allocate resources simultaneously for different TTI types. This enables continuous spectrum utilization without the gaps and delays inherent in time-division approaches, significantly improving spectrum efficiency.
Solution Approach 2:
The patent divides the total available spectrum into distinct segments or bands, assigning specific frequency portions to shortened TTI UEs and others to normal TTI UEs. This segmentation allows parallel, efficient use of spectrum resources without the waste associated with time-division multiplexing.
3Productivity
If separate frequency bands are allocated for different TTI types, then spectrum utilization improves and latency reduces, but system complexity increases
Solution Approach 1:
The patent employs a universal frequency allocation framework where the same frequency division principles can be applied across different network configurations and UE types. This multi-functional approach, combined with standardized control signaling mechanisms, manages the added complexity through uniform procedures rather than case-specific handling.
Data Source
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AI summary
In some aspects, a user equipment (UE) may receive first downlink control information (DCI) scheduling a start of a data communication in a first transmission time interval (TTI) on a first frequency band configured with an uplink/downlink time division duplexing (TDD) pattern that is synchronized with a second frequency band. The UE may receive or transmit a first portion of the data communication in the first TTI based at least in part on receiving the first DCI. The UE may receive second DCI that schedules a second portion of the data communication in a second TTI on the first frequency band, the second DCI indicating that the second portion is part of the data communication. The UE may receive or transmit the second portion of the data communication in the second TTI based at least in part on receiving the second DCI.