Decoupled Uplink Burst for TDD Latency Reduction
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Solution Overview
Problem
In wireless communication networks using time division duplex (TDD) technology, there is a challenge in reducing latency for time-sensitive uplink transmissions, particularly in scenarios where uplink-centric subframes are rare, leading to delayed transmission of critical control information and data.
Innovation Solution
The implementation of a common uplink burst in every subframe, decoupling the latency of control channel and uplink/downlink patterns, allows for timely transmission of control information and data, including a sounding reference signal, within a common uplink burst region, which can be configured in both coupled and decoupled modes to accommodate users at cell edges and centers respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If uplink-centric subframes are used for uplink transmissions, then uplink data can be transmitted, but latency increases when uplink-centric subframes are rare
Solution Approach 1:
The patent segments the uplink transmission opportunities by creating two distinct modes: common uplink burst for control information and decoupled mode for data transmission. This segmentation allows control information to be transmitted in every subframe while data transmission occurs in uplink-centric subframes, resolving the latency issue without sacrificing overall transmission efficiency
Solution Approach 2:
The patent implements preliminary action by transmitting control information (such as scheduling requests and channel quality indicators) in the common uplink burst before actual data transmission. This allows the network to prepare and allocate resources in advance, reducing the overall latency for time-sensitive operations while maintaining efficient data transmission in decoupled mode
2Loss of time
If common uplink burst is implemented in every subframe, then latency for control information is reduced, but resource allocation complexity increases
Solution Approach 1:
The patent applies dynamics by making the uplink transmission mode flexible and configurable. Users can be dynamically assigned to either coupled mode or decoupled mode based on their location (cell edge vs. cell center) and traffic requirements. This dynamic assignment simplifies resource allocation by providing clear, location-based rules rather than complex general-purpose scheduling
Solution Approach 2:
The patent implements local quality by providing different transmission modes tailored to specific user locations and requirements. Cell edge users use coupled mode optimized for reliability, while cell center users use decoupled mode optimized for low latency. This localized optimization reduces overall system complexity by addressing specific needs rather than designing a single complex solution for all users
3Loss of time
If decoupled mode is used for users at cell center, then latency is reduced, but coverage for cell edge users deteriorates
Solution Approach 1:
The patent applies local quality by providing different transmission modes tailored to specific user locations and requirements. Cell edge users use coupled mode optimized for reliability, while cell center users use decoupled mode optimized for low latency. This localized optimization reduces overall system complexity by addressing specific needs rather than designing a single complex solution for all users
Solution Approach 2:
The patent applies dynamics by making the uplink transmission mode flexible and configurable. Users can be dynamically assigned to either coupled mode or decoupled mode based on their location (cell edge vs. cell center) and traffic requirements. This dynamic assignment simplifies resource allocation by providing clear, location-based rules rather than complex general-purpose scheduling
Data Source
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AI summary
Various aspects of the present disclosure provide for methods, apparatus, and computer software for transmitting a common uplink burst in time division duplex (TDD) carriers. The common uplink burst includes a sounding reference signal (SRS) transmitted separate from (e.g., decoupled from) a demodulation reference signal (DM-RS). At least one symbol in the common uplink burst includes a control region for carrying control information and a data region for carrying data information. The SRS may be precoded separately from precoding of the control and data regions, so that the control and/or data information may be transmitted utilizing multiple input multiple output (MIMO).