PDSCH TTI Bundling for LTE Coverage
Solution Overview
Problem
Current LTE technologies face challenges in efficiently supporting low-cost, low-rate devices due to high bandwidth and power consumption requirements, and existing TTI bundling methods for PDSCH in LTE systems result in collisions with reference signals, leading to suboptimal performance and coverage issues, especially for machine type communications.
Innovation Solution
Implementing subframe-dependent TTI bundling for PDSCH, where only a subset of subframes is used for data transmission, allowing for the dropping or puncturing of reference signals to avoid collisions, and employing rate matching around resource elements occupied by reference signals, tailored for different types of PDSCH operations such as paging and system information blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional TTI bundling methods are used for PDSCH, then data transmission is performed in all subframes, but collisions with reference signals occur leading to suboptimal performance and coverage issues
Solution Approach 1:
The patent segments the TTI bundle by identifying and excluding specific subframes that contain reference signals from the data transmission subset. This segmentation prevents collisions between PDSCH data and reference signals while maintaining efficient use of remaining subframes, thereby improving coverage performance without harmful collisions.
Solution Approach 2:
The patent applies local quality by treating different subframes differently within the TTI bundle. Subframes containing reference signals are identified and excluded from data transmission, while other subframes continue normal data transmission. This localized adjustment prevents collisions in critical subframes while maintaining overall system efficiency.
2Productivity
If all subframes are used for data transmission in TTI bundling, then transmission efficiency is high, but power consumption increases and low-cost devices cannot be supported
Solution Approach 1:
The patent extracts and removes reference signal resource elements from subframes that would otherwise be used for data transmission. By identifying subframes containing reference signals and excluding them from the data transmission subset, the system reduces unnecessary power consumption while maintaining transmission efficiency in remaining subframes, enabling support for low-cost devices.
3Measurement precision
If reference signals are retained in all subframes, then channel estimation accuracy is maintained, but data transmission efficiency decreases due to collisions
Solution Approach 1:
The patent segments the TTI bundle to separate reference signal subframes from data transmission subframes. Reference signals are maintained in their original subframes for accurate channel estimation, while data transmission is performed only in subframes without reference signals, eliminating collisions and improving overall transmission efficiency.
Data Source
AI summary
Certain aspects of the present disclosure propose techniques for transmission time interval (TTI) bundling for physical downlink shared channel (PDSCH) in long term evolution (LTE). According to certain aspects a method is provided for wireless communications. The method may be performed, for example, by a user equipment (UE). The method generally includes identifying a transmit time interval (TTI) bundle comprising a subset of subframes from a set of subframes for transmitting data on a physical downlink shared channel (PDSCH) and receiving the data on the PDSCH in the subset of subframes.