TDD Special Subframe TTI Bundling for Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing TDD system cannot employ TTI bundling with UL/DL configuration 2 and other configurations to enhance coverage, limiting the ability to improve cell coverage in scenarios where TD-SCDMA networks coexist with LTE TDD systems.
Innovation Solution
The method involves using special subframes for TTI bundling, where a base station determines the need for special subframes based on resource allocation and interference, and sends a message to user equipment (UE) to transmit TTI bundling packets on either special or normal subframes, allowing for enhanced coverage by configuring redundancy versions and resource allocation specific to each subframe type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TTI bundling is used to improve cell coverage, then coverage is enhanced, but it cannot be applied with UL/DL configuration 2 and other configurations in TDD systems
Solution Approach 1:
The patent segments the TDD subframes into different types (first type with more DL subframes, second type with more UL subframes) and applies TTI bundling selectively to uplink subframes within these segmented configurations. This allows TTI bundling to be adapted to work with UL/DL configurations 2, 3, and 4 that previously did not support it, while maintaining coverage enhancement benefits.
2Adaptability or versatility
If UL/DL configuration 2 is used for TDD system coexistence with TD-SCDMA network, then coexistence compatibility is improved, but TTI bundling cannot be used to enhance coverage
Solution Approach 1:
The patent introduces dynamic adaptation by allowing the system to flexibly apply TTI bundling to uplink subframes within UL/DL configuration 2 when coexisting with TD-SCDMA networks. The base station can dynamically determine whether to apply TTI bundling based on channel conditions and interference levels, enabling both configuration 2 compatibility and coverage enhancement to coexist.
3Reliability
If special subframes are introduced for TTI bundling, then coverage enhancement is achieved, but system complexity increases
Solution Approach 1:
The patent makes existing uplink subframes in UL/DL configurations 2, 3, and 4 multi-functional by enabling them to support both normal uplink transmission and TTI bundling operations. Instead of creating entirely new special subframe structures, the invention repurposes existing uplink subframes to serve dual functions, thereby achieving coverage enhancement without significantly increasing system complexity.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Embodiments of the disclosure provide a method and apparatus for enhancing coverage in a TDD system, wherein there is at least one TDD UL/DL configuration for subframes in the TDD system, and the at least one UL/DL configuration comprises at least one special subframe and at least one normal subframe. In the method according to embodiments of the present invention, whether a special subframe is to be applied in TTI bundling is determined first, and then a message with an indication indicating that a special subframe is to be applied in TTI bundling is sent to a UE in response to determining that a special subframe is to be applied in TTI bundling, such that the UE transmits TTI bundling packets on at least one special subframe.