Base Station Channel Preservation in Unlicensed Bands
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Solution Overview
Problem
Wireless communication systems using unlicensed frequency bands face challenges in coexisting with other radio access technologies (RATs) like WLAN, leading to potential loss of transmission opportunities due to unpredictable channel idle times and interference.
Innovation Solution
Implementing a method for base stations to determine and preserve channels using single, synchronous, or asynchronous multi-channel operations, transmitting a channel preservation signal until the start of a subframe to prevent loss of transmission opportunities and minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station waits for the subframe boundary to transmit control information, then the transmission timing is synchronized and controlled, but the base station loses transmission opportunities when the channel is occupied by other RATs
Solution Approach 1:
The base station performs preliminary channel sensing before the subframe boundary and transmits control information as soon as the channel is determined to be idle, rather than waiting for the subframe boundary. This preliminary action allows the base station to capture transmission opportunities immediately when the channel becomes available, reducing channel idle time while maintaining transmission reliability
Solution Approach 2:
The base station dynamically adjusts its transmission timing based on real-time channel conditions. Instead of following a fixed subframe boundary schedule, the base station flexibly transmits control information at variable timings determined by channel availability, optimizing the balance between transmission reliability and time utilization
2Productivity
If the base station transmits control information immediately when the channel is idle, then transmission opportunities are captured quickly, but transmission timing becomes unsynchronized and difficult to control
Solution Approach 1:
The base station performs preliminary actions including channel sensing, terminal identification, and transmission timing determination before actual control information transmission. This structured preliminary sequence enables immediate transmission when channel is idle while maintaining timing control through predefined procedural steps
Solution Approach 2:
The base station autonomously determines transmission timing based on channel conditions and terminal states without requiring complex external coordination. The system self-adjusts its timing by monitoring channel idle status and automatically selecting appropriate transmission moments, reducing timing control complexity while maintaining high transmission speed
3Reliability
If the base station uses channel preservation signals to prevent loss of transmission opportunities, then transmission reliability is improved, but frequency resource utilization decreases due to increased signal usage
Solution Approach 1:
The base station extracts and removes unnecessary channel preservation signals from the transmission sequence. By eliminating redundant preservation signals while maintaining essential ones, the base station preserves transmission opportunities reliably while reducing overall signal usage and improving frequency resource utilization
Solution Approach 2:
The base station applies channel preservation selectively rather than uniformly across all transmissions. Preservation signals are used only in specific local conditions where transmission opportunities are at risk, rather than continuously, thereby maintaining reliability where needed while minimizing impact on frequency resource utilization
Data Source
AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A method and an apparatus for operating a base station and a terminal in a wireless communication system using an unlicensed band are provided. The base station can determine at least one channel in at least one unlicensed band using one of a single channel operation and a multi-channel operation, acquire the at least one channel according to a data transmission request, and transmit a channel preservation signal until a start point of a first subframe transmitted on the acquired at least one channel.