Subband Full Duplex Resource Allocation for TDD Uplink Bottlenecks
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Solution Overview
Problem
TDD systems in wireless mobile communication face challenges with reduced coverage, increased latency, and reduced capacity due to limited uplink time duration, which can be addressed by implementing sub-band full duplex (SBFD) to enable simultaneous downlink and uplink operations within a conventional TDD band.
Innovation Solution
A method and apparatus support sub-band full duplex by configuring terminals to receive system information, determine DL, UL, and SBFD symbols, and allocate initial BWPs and PRBs, enabling random access procedures based on these resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TDD time domain resource is split between downlink and uplink, then system simplicity is maintained, but uplink coverage is reduced and latency increases
Solution Approach 1:
The patent segments the frequency band into multiple subbands, allowing different subbands to operate in different directions (downlink, uplink, or flexible) simultaneously. This segmentation enables the system to overcome the limitations of TDD by creating dedicated uplink subbands that can operate continuously, thereby improving uplink capacity and reducing latency without affecting the overall system structure.
Solution Approach 2:
The patent transitions from time-domain division (TDD) to frequency-domain division by introducing subband full duplex operation. Instead of allocating different time slots for uplink and downlink, the system divides the frequency spectrum into multiple subbands, allowing simultaneous uplink and downlink transmissions in different frequency ranges. This dimensional change from time to frequency resolves the latency and capacity issues inherent in TDD.
2Productivity
If simultaneous downlink and uplink operations are implemented, then capacity and coverage are improved, but system complexity increases
Solution Approach 1:
The patent introduces dynamic resource allocation where subbands can be flexibly configured as downlink, uplink, or flexible subbands based on traffic demands. The network can dynamically adjust the number, position, and direction of subbands through system information broadcasting and RRC configuration, allowing the system to adapt to varying conditions while maintaining manageable complexity through standardized procedures.
Solution Approach 2:
The patent creates a universal resource allocation framework that can handle multiple operation modes (TDD, FDD, and subband full duplex) within the same system. The flexible subband configuration allows resources to serve multiple purposes - dedicated uplink subbands for continuous transmission, dedicated downlink subbands for broadcast, and flexible subbands that can be dynamically assigned based on needs, thereby improving capacity without proportionally increasing complexity.
3Length of stationary object
If uplink time duration is limited in TDD, then downlink performance is maintained, but uplink coverage is reduced
Solution Approach 1:
The patent enables continuous uplink transmission by allocating dedicated uplink subbands that operate continuously rather than in periodic time slots. This continuity of useful action allows terminals to maintain constant uplink connectivity, improving coverage by eliminating the gaps inherent in TDD time-slot structures and allowing uplink signals to be transmitted without interruption regardless of downlink requirements.
Data Source
AI summary
A method and apparatus to support sub-band full duplex is provided. In the method the terminal receives from a base station a system information; the terminal determines DL symbols, UL symbols, flexible symbols and SBFD symbols; the terminal determines initial uplink BWP, initial downlink BWP and SBFD PRBs; the terminal determines initial uplink time/frequency resource, initial downlink time/frequency resource and SBFD time/frequency resource; and the terminal performs random access procedure based on determined resource.