TTI Bundling in Special Subframes for Uplink Coverage
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Solution Overview
Problem
The TD-LTE system's limited uplink coverage in certain subframe configurations, particularly in configurations #2 and #3, due to the lack of support for Physical Uplink Shared Channel (PUSCH) transmission within special subframes and TTI bundling in Time Division Duplexing (TDD) systems, results in insufficient coverage for some subframe configurations.
Innovation Solution
A method for determining the first start subframe for PUSCH transmission and bundling multiple subframes, including a special subframe with an Uplink Pilot Time Slot (UpPTS), to achieve TTI bundling transmission, thereby improving uplink coverage by scaling the quantity of physical blocks and configuring transmission power for each subframe and UpPTS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TTI bundling is implemented in conventional TDD subframe configurations, then uplink coverage is improved, but it is not supported in configurations #2 and #3
Solution Approach 1:
The patent makes the TTI bundling mechanism adaptable to different subframe configurations by dynamically determining which subframes can be bundled based on their types. The system selectively applies bundling to compatible subframe configurations while excluding configurations #2 and #3, thereby maintaining both coverage improvement and configuration adaptability.
Solution Approach 2:
The patent changes the parameter of subframe bundling eligibility based on subframe configuration type. By introducing configuration-specific bundling rules, the system allows TTI bundling to function in supported configurations while gracefully handling unsupported configurations, thus resolving the contradiction between coverage improvement and configuration compatibility.
2Reliability
If PUSCH transmission is not supported in special subframes, then system complexity is reduced, but uplink coverage becomes insufficient
Solution Approach 1:
The patent applies local quality by allowing PUSCH transmission only in specific subframe types (normal uplink subframes and special subframes with UpPTS) while maintaining the restriction for other subframe configurations. This selective approach improves uplink coverage in supported configurations without unnecessarily increasing system complexity across all configurations.
3Reliability
If basic TTI length of 1ms is used, then time delay is reduced, but coverage at cell edges is limited
Solution Approach 1:
The patent merges multiple 1ms TTI subframes into a bundled transmission group, allowing the UE to transmit the same data across multiple subframes. This combining approach maintains the basic 1ms TTI timing for low latency while achieving extended coverage through cumulative transmission energy across the bundled subframes.
Data Source
Figure 1~2
Figure 3A~3C
Figure 3D~4B
AI summary
The present disclosure provides a transmission method, a transmission device, a mobile communication terminal, and a network side device, so as to implement bundling transmission of an uplink shared channel. The transmission method includes: a subframe determination step of determining, by a UE, a first start subframe within which a PUSCH is to be transmitted currently; and a first transmission step of, when a bundling transmission condition has been met, bundling a plurality of subframes from the first start subframe, and transmitting the PUSCH through uplink resources in the bundled subframes, the bundled subframes at least comprising a special subframe having an UpPTS capable of being adopted for transmitting the PUSCH.