Base Station Synchronization Signal Transmission in Unlicensed Bands
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Solution Overview
Problem
In wireless communication systems, especially in unlicensed bands, there is a challenge in coordinating channel access to prevent collisions between different terminals, and existing methods struggle with ensuring reliable transmission of synchronization signals due to unpredictable channel conditions.
Innovation Solution
Implementing a method where a base station performs listen-before-talk (LBT) within a defined window duration to transmit synchronization signals, allowing for flexible timing and reducing the likelihood of collisions by including periodicity and duration information within the synchronization signal block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base station transmits synchronization signals in unlicensed bands without coordinated channel access, then transmission simplicity is maintained, but channel collisions occur and transmission reliability deteriorates
Solution Approach 1:
The base station performs listen-before-talk (LBT) procedure before transmitting the synchronization signal block. This preliminary channel sensing action allows the base station to check if the channel is busy or free, thereby avoiding channel collision and improving transmission reliability without requiring complex continuous coordination mechanisms
Solution Approach 2:
The synchronization signal block is transmitted periodically with a defined transmission period. This periodic transmission pattern allows terminals to predict and synchronize with the signal timing, improving reception reliability while maintaining simple channel access coordination through the window duration mechanism
2Ease of operation
If the base station waits for channel availability without a defined window duration, then channel access flexibility is improved, but transmission timing predictability deteriorates
Solution Approach 1:
The base station performs LBT procedure in advance within a defined window duration before the expected transmission time. This preliminary action allows the base station to secure channel access early, reducing the waiting time for terminals while maintaining flexibility in actual transmission timing within the window
Solution Approach 2:
The channel access mechanism dynamically adjusts the transmission timing within the window duration based on LBT results. If the channel becomes available earlier than expected, the base station can transmit sooner; if not, it waits until the channel is free, all within the defined window, providing both flexibility and time predictability
3Measurement precision
If synchronization signal transmission uses fixed timing without periodicity information, then transmission simplicity is maintained, but terminal synchronization accuracy deteriorates
Solution Approach 1:
The base station embeds periodicity information and transmission timing information directly into the synchronization signal block before transmission. This preliminary inclusion of timing data allows terminals to accurately determine the transmission period and synchronize their reception timing without requiring complex external synchronization mechanisms
Solution Approach 2:
The synchronization signal block contains embedded information about the transmission period and timing, which serves as feedback to the terminals about the expected signal pattern. This feedback mechanism enables terminals to accurately synchronize by using the provided periodicity information to predict subsequent transmissions
Data Source
AI summary
The present disclosure relates to a method and apparatus for transmitting and receiving data in a wireless communication system. A method of a base station for transmitting and receiving a synchronization signal includes performing listen-before-talk (LBT) on a channel of a terminal in an unlicensed band, and in case that the LBT succeeds within a window duration for transmitting a synchronization signal block (SSB), transmitting the SSB to the terminal, wherein the window duration includes at least one SSB burst length that is repeated in a specific period and has the specific period as a length of time, and the SSB is transmitted at a specific time within a first SSB burst length of the at least one SSB burst length.