TTI Bundling Configuration for Uplink Coverage in TDD Systems
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Solution Overview
Problem
Current mobile communication systems face challenges in improving uplink coverage, particularly at the cell edge, due to limited transmit power of terminals and the need for reduced base station deployment, which is exacerbated by the limited configurations supporting TTI bundling in TDD wireless systems.
Innovation Solution
The method involves configuring variable subframes for data transmission using TTI bundling and adjusting uplink and ACK/NACK transmission timing, allowing TTI bundling to be applied across various TDD configurations, including releasing Carrier Aggregation to enhance uplink data transmission coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TTI bundling is applied to improve uplink coverage, then uplink data transmission coverage is improved, but the number of supported TDD configurations is limited
Solution Approach 1:
The patent makes the TTI bundling configuration dynamic by allowing the base station to flexibly configure and signal the number of bundled subframes to terminals through higher layer signaling. This enables the system to adapt TTI bundling to various TDD uplink/downlink configurations dynamically, rather than being fixed to specific configurations, thereby resolving the contradiction between improving uplink coverage and supporting multiple configurations.
2Reliability
If transmit power of terminal is increased to improve uplink coverage, then uplink coverage is improved, but terminal power constraints are violated
Solution Approach 1:
The patent combines multiple uplink transmissions of the same data across multiple bundled subframes with different redundancy versions. By merging these transmissions and using chase combining or incremental redundancy at the base station, the system achieves improved coverage without requiring the terminal to increase its transmit power, thus resolving the contradiction between coverage improvement and power constraints.
3Ease of manufacture
If the number of base stations is reduced to lower deployment cost, then deployment cost is reduced, but uplink coverage is degraded
Solution Approach 1:
The patent implements continuous transmission of uplink data across multiple bundled subframes, ensuring that the terminal can continuously transmit data even when experiencing poor signal conditions at the cell edge. This continuous transmission approach compensates for the reduced number of base stations by maximizing the utilization of each base station's coverage area, thereby resolving the contradiction between deployment cost and coverage.
Data Source
AI summary
A method of transmitting data for uplink coverage for improvement of a wireless communication system by a terminal improving uplink data transmission reliability so as to be capable of successful data transmission. A method for transmitting and receiving a signal of a terminal in a time division wireless communication system of the present invention includes receiving a TTI bundling setting command from a base station, confirming whether a TTI bundling number is included in the TTI bundling setting command, determining the time when a signal is transmitted and received according to the TTI bundling number, when the TTI bundling number is included and determining the time when a signal is transmitted and received according to a preset TTI bundling number, when the TTI bundling number is not included.