Uplink Grant Transmission in LTE FDD Subframes
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Solution Overview
Problem
In wireless communication systems, transmitting an uplink grant in certain subframes is challenging due to resource constraints and interference, particularly in subframes where downlink control information is difficult to detect or resources are insufficient for proper transmission.
Innovation Solution
A method and device for transmitting an uplink signal by receiving a downlink control information including an uplink grant, where the uplink grant is applied to a subsequent subframe, allowing for efficient resource allocation and maintaining HARQ timing by using US-RNTI masking and offset values, and optionally applying to both the subframe with the grant and subsequent subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an uplink grant is transmitted in a subframe with resource constraints or interference, then the uplink resource allocation flexibility is improved, but the transmission reliability deteriorates
Solution Approach 1:
The patent segments the uplink grant transmission by applying it to multiple different subframes (kth subframe and Lth subframe) rather than a single subframe. This segmentation allows the system to distribute the grant transmission across multiple opportunities, improving flexibility while maintaining reliability through redundant transmission paths.
Solution Approach 2:
The patent applies preliminary action by transmitting the uplink grant in advance in a subframe before the actual uplink data transmission. This allows the user equipment to prepare and allocate resources beforehand, improving both flexibility in resource allocation and reliability by ensuring grants are received before needed.
2Productivity
If the uplink grant is applied to both the current subframe and subsequent subframe, then the resource utilization is improved, but the system complexity increases
Solution Approach 1:
The patent makes the uplink grant universal by applying it to multiple subframes (both the kth subframe and the Lth subframe). This multi-functionality allows a single grant transmission to serve multiple purposes and time periods, improving resource utilization without requiring separate grant transmissions for each subframe.
Solution Approach 2:
The patent implements periodic action by establishing a pattern where the uplink grant applies periodically to the kth subframe and then to the Lth subframe appearing after the first subframe. This periodic application improves resource utilization by creating predictable, repeating grant patterns that reduce the need for frequent re-transmissions.
3Reliability
If HARQ timing is maintained by transmitting uplink grant in difficult subframes, then the communication reliability is improved, but the timing synchronization becomes more challenging
Solution Approach 1:
The patent uses feedback mechanisms where the uplink grant includes timing information that provides feedback to the user equipment about when to transmit uplink data. This feedback loop maintains HARQ timing by ensuring the UE transmits at the correct time even when grants are received in difficult subframes, improving reliability while managing timing synchronization.
Data Source
AI summary
A user equipment (UE) is provided in a long term evolution (LTE) frequency division duplex (FDD) system. The UE receives a downlink control information (DCI) including a UL grant for transmitting the UL signal in an N-th subframe, and transmits the UL signal using the UL grant, in at least one of an (N+4)-th subframe and an (M+4)-th subframe. An M-th subframe is a subframe in which both of a physical downlink control channel (PDCCH) and an enhanced PDCCH (EPDCCH) are not transmitted. N and M are integers, and M is greater than N.