Wireless Signal Reception in Licensed-Unlicensed Cell Systems
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Solution Overview
Problem
Current wireless communication systems, such as LTE, face challenges in efficiently transmitting and receiving signals across cells configured with different characteristics, particularly in environments where licensed and unlicensed bands are used simultaneously, leading to issues with interference and resource management.
Innovation Solution
A method is introduced where user equipment performs blind decoding to treat an uplink subframe of one cell as a downlink subframe in a TDD frame structure, allowing for signal reception from a second cell on an unlicensed band, with dynamic reconfiguration of subframe configurations and HARQ reference configurations, enabling efficient signal transmission and reception across multiple bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blind decoding is performed to treat uplink subframe as downlink subframe for receiving signals from unlicensed band cells, then signal reception capability is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic subframe configuration where the base station can dynamically indicate whether a specific uplink subframe should be treated as a downlink subframe through downlink control information. This allows the user equipment to adaptively switch between uplink and downlink reception modes based on real-time scheduling requirements, improving signal reception capability while avoiding permanent structural complexity
Solution Approach 2:
The patent changes the operational parameter of subframe direction (uplink/downlink) dynamically through control signaling. By modifying the subframe configuration parameter based on whether the subframe falls within an on-duration of a discontinuous reception cycle, the system enables flexible signal reception without requiring complex hardware modifications
2Productivity
If multiple cells with different characteristics are configured simultaneously, then resource utilization is improved, but interference increases
Solution Approach 1:
The patent segments the operation of unlicensed band cells by introducing discontinuous reception cycles with specific on-durations and off-durations. By dividing the time domain into active reception periods and idle periods, the system allows multiple cells to operate simultaneously during off-durations without interfering with each other, while maintaining resource utilization during on-durations
Solution Approach 2:
The patent implements periodic discontinuous reception cycles where the user equipment alternates between monitoring and non-monitoring states. This periodic action creates predictable interference patterns that can be managed through coordination, allowing multiple cells to share the unlicensed spectrum efficiently by staggering their active periods
3Adaptability or versatility
If dynamic reconfiguration of subframe configurations is performed, then adaptability is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary configuration by establishing discontinuous reception cycles and subframe patterns in advance through system information broadcasting. The user equipment is pre-configured with the structure of on-durations and off-durations, eliminating the need for real-time negotiation and reducing the time loss associated with dynamic reconfiguration
Data Source
AI summary
A method for receiving a signal by a terminal, having a plurality of cells configured, in a wireless communication system according to an embodiment of the present invention comprises the steps of: assuming a first uplink subframe of a first cell, having a time division duplex (TDD) frame structure among a plurality of cells, to be a downlink subframe on the basis of a predetermined condition and blind-decoding same; and, if a downlink grant with respect to a second cell, located in an unlicensed band among the plurality of cells, is detected by means of the blind-decoding, receiving downlink data through the second cell, wherein the first uplink subframe is indicated as an uplink subframe by means of a first uplink-downlink subframe configuration in an enhanced interface mitigation and traffic adaptation (eIMTA) fallback comprised in a system information block type 1 (SIB 1) and at the same time is indicated as a downlink subframe by means of downlink hybrid automatic repeat request (HARQ) reference configuration in the eIMTA fallback.