Slotted Sub-band Duplex Frame Structure for TDD Latency
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Solution Overview
Problem
Current wireless communication systems employing time-division duplex technologies face inefficiencies in spectral utilization and latency, particularly in supporting diverse latency requirements for different services, leading to challenges in multiplexing traffic with varying latency targets.
Innovation Solution
The implementation of configurable frame structures that allow trade-offs between spectral utilization and signaling latency by using duplex symbols for both uplink and downlink transmissions, enabling efficient scheduling and transmission of control and data signals, including the use of orthogonal frequency division multiplexing and carrier aggregation to optimize bandwidth allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional time-division duplex frame structures are used, then system simplicity is maintained, but spectral utilization efficiency deteriorates
Solution Approach 1:
The frame structure is segmented into multiple slots, each containing duplex symbols with separate uplink and downlink sub-bands. This segmentation allows independent optimization of uplink and downlink resource allocation, improving spectral utilization by enabling simultaneous bidirectional communication on different frequency sub-bands within the same time slot.
Solution Approach 2:
The patent introduces a frequency dimension separation within time-division duplexing by allocating specific sub-bands for uplink and downlink transmissions simultaneously. This adds a frequency-layer dimension to the traditional time-division approach, enabling parallel uplink-downlink communication and improving spectral efficiency without excessive complexity.
2Loss of information
If longer frame durations are used, then more scheduling information can be transmitted, but signaling latency increases
Solution Approach 1:
Scheduling information for future frames is transmitted in advance within the current frame's duplex symbols. This preliminary action allows receiving devices to prepare for upcoming transmissions, reducing signaling latency by eliminating the need to wait for the next frame boundary to receive scheduling decisions.
Solution Approach 2:
The frame structure enables continuous transmission of scheduling information across frame boundaries by utilizing duplex symbols at frame transitions. This continuity ensures that scheduling information flow never interrupts, maintaining low latency while providing sufficient capacity for comprehensive scheduling decisions.
Data Source
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AI summary
A method, an apparatus, and a computer program product for wireless communication are provided. The method includes scheduling at a scheduling entity, a first frame for transmission over a wireless network that supports time division duplexing (TDD), where the first frame includes a first duplex symbol that includes a first bandwidth to be used for uplink transmission to the scheduling entity and a second bandwidth to be used for downlink transmission from the scheduling entity, and using the second bandwidth to transmit scheduling information while the first frame is being transmitted. The scheduling information may be related to a second frame that is scheduled to be transmitted immediately after the first frame. The scheduling information includes an uplink grant or a downlink grant.