TTI Bundling for Coverage Enhancement in Low-Complexity UEs
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Solution Overview
Problem
Current wireless communication systems face challenges in providing effective coverage to low-complexity user equipment (UEs) with intermittent communication needs, particularly at the periphery of a base station's coverage range, due to limitations in signal strength and power efficiency.
Innovation Solution
The implementation of transmission time interval (TTI) bundling and threshold-dependent encoding schemes, which allow for the identification of optimal encoding methods based on TTI bundling length and channel associations, to enhance signal strength and power efficiency for low-complexity UEs, including those with reduced peak data rates and transmit power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional wireless communication methods are used for low-complexity UEs, then device complexity is reduced, but coverage range and signal strength deteriorate at the periphery of base station coverage
Solution Approach 1:
The patent combines multiple transmission time intervals (TTIs) into a single bundled transmission unit. By merging consecutive TTIs carrying the same transport block with identical encoding, the system achieves signal reinforcement through combining at the receiver, thereby extending coverage to low-complexity UEs at the periphery without increasing device complexity
Solution Approach 2:
The patent changes the transmission parameter by introducing TTI bundling length as a controllable variable. By adjusting the bundling length parameter, the system optimizes the trade-off between coverage enhancement and resource consumption, enabling low-complexity UEs to operate effectively at coverage edges while maintaining acceptable power efficiency
2Area of stationary object
If transmission power is increased to extend coverage, then coverage range improves, but power consumption increases
Solution Approach 1:
Instead of increasing transmit power, the patent merges multiple TTIs into bundles and combines signals at the receiver side. This approach achieves coverage extension through constructive signal combining rather than power amplification, thereby maintaining power efficiency while extending coverage range for low-complexity UEs
Solution Approach 2:
The patent introduces TTI bundling as an intermediary mechanism between the transmitter and receiver. By using bundling length as a mediator parameter, the system achieves coverage enhancement through controlled signal repetition and combining, avoiding direct power increase while extending effective coverage area
3Strength
If TTI bundling is used to enhance coverage, then signal strength improves, but transmission overhead increases
Solution Approach 1:
The patent introduces TTI bundling length as a configurable parameter to control the degree of bundling. By optimizing this parameter, the system achieves sufficient signal strength enhancement while minimizing the overhead introduced by repeated transmissions, balancing coverage improvement with resource efficiency
Solution Approach 2:
The patent applies partial bundling rather than bundling all transmissions. By selectively applying TTI bundling only when needed for coverage enhancement and using minimal bundling length, the system achieves necessary signal strength improvement while avoiding excessive overhead, implementing just enough repetition to reach the coverage target
Data Source
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AI summary
Methods, systems, and devices are described for wireless communication within and for user equipment (UE), including lower-complexity devices, which may have intermittent communication needs, low data rates, hard-to-reach locations, and the like. Devices within a wireless communication system may utilize transmission time interval (TTI) bundling to identify and employ various encoding schemes according to particular channel, transmission, and/or environmental conditions. Devices may also monitor and/or decode control-based transmission, control-less transmission, or both. In some examples, devices may monitor various channels based on a TTI bundling length. Some or any of these techniques may allow for coverage enhancement of UEs, including low-complexity UEs.