Uplink Signal Transmission Timing in Unlicensed Bands
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Solution Overview
Problem
In wireless communication systems, particularly in 5G networks, there is a challenge in accurately setting uplink signal transmission timing for terminals operating in unlicensed bands, leading to potential delays or failures in signal transmission due to unavailability of idle states, which affects performance and synchronization between base stations and terminals.
Innovation Solution
A method is introduced where the base station configures uplink signal transmission timing for terminals, allowing them to perform channel access procedures before transmission and adjust start times based on idle state determinations, enabling flexible transmission schedules to improve performance even when initial scheduled times are not feasible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station schedules uplink signal transmission at a specific timing, then the transmission timing is determined and synchronized, but the terminal cannot transmit when the unlicensed band is not idle, leading to transmission failures or delays
Solution Approach 1:
The patent applies dynamics by making the uplink transmission timing flexible rather than fixed. The base station configures multiple candidate transmission timings, and the terminal dynamically selects from these candidates based on the actual channel access outcome. This dynamic adjustment allows the system to adapt to the unlicensed band's idle state availability, resolving the contradiction between maintaining scheduled transmission reliability and avoiding transmission delays when the band is busy.
Solution Approach 2:
The patent changes the timing parameter from a single fixed value to multiple configurable candidate values. The base station configures a set of candidate transmission timings, and the terminal selects one based on channel conditions. This parameter change enables the system to transition between different transmission timing states, allowing reliable transmission when the band is idle and avoiding delays by selecting alternative timings when the band is busy.
2Ease of operation
If the terminal performs channel access procedure before scheduled transmission, then it can determine if the band is idle, but the transmission timing may be missed requiring alternative timing selection
Solution Approach 1:
The patent applies preliminary action by having the terminal perform the channel access procedure before the scheduled transmission timing. This advance channel checking allows the terminal to determine whether the unlicensed band is idle before committing to transmission. If the band is found to be busy, the terminal can proactively select an alternative timing from the configured candidates, avoiding transmission conflicts and timing losses.
Solution Approach 2:
The patent implements feedback by using the channel access outcome to determine transmission timing selection. The terminal receives feedback from the channel access procedure about band availability and uses this feedback to select appropriate transmission timing from the configured candidates. This feedback mechanism ensures that transmission decisions are based on actual channel conditions, resolving the contradiction between ease of channel access operation and transmission timing accuracy.
3Adaptability or versatility
If multiple uplink signal transmission timings are configured, then flexibility is improved for channel access, but the complexity of determining the correct timing increases
Solution Approach 1:
The patent applies segmentation by dividing the transmission timing into multiple discrete candidate values configured by the base station. Instead of requiring the terminal to calculate or determine timing continuously, the base station segments the timing space into specific candidate slots. The terminal then simply selects from these pre-segmented options based on channel access outcomes, reducing determination complexity while maintaining flexibility.
Solution Approach 2:
The patent implements self-service by enabling the terminal to autonomously select transmission timing from the configured candidates based on its own channel access results. The terminal uses its received signal strength measurements and pre-configured candidate timings to independently determine the appropriate transmission timing without requiring complex base station coordination or additional signaling, thus reducing overall system complexity while maintaining adaptability.
Data Source
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AI summary
A communication method and system for converging a 5th-generation (5G) communication system for supporting higher data rates beyond a 4th-generation (4G) system with a technology for internet of things (IoT). The disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology. The method of a terminal in a wireless communication system are provided. The method includes receiving information, which is related to a first transmission time and a second transmission time of an uplink signal of a terminal, from a base station, when the uplink signal of the terminal is configured in an unlicensed band, performing a channel access in the unlicensed band, and when the unlicensed band is not in an idle state based on a channel access result before the first transmission time, performing a channel access until the second transmission time.