Wireless Terminal Transmission Timing Coordination
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Solution Overview
Problem
In wireless communications systems using unlicensed bandwidth, existing technologies face challenges in coordinating uplink user multiplexing across terminals, leading to transmission collisions and reduced throughput due to differing transmission timing and carrier sensing methods.
Innovation Solution
A wireless communications system where terminals calculate a common transmission start timing based on a control signal from the base station, performing carrier sensing before transmission, and initiating transmission only when no wireless signal is detected in the shared bandwidth for a predetermined period, thereby synchronizing transmission and avoiding collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If terminals perform independent carrier sensing and transmission without coordination, then transmission timing flexibility is improved, but transmission collisions occur and throughput decreases
Solution Approach 1:
The base station performs preliminary actions by determining a common transmission start timing and notifying all terminals of this timing before actual uplink transmission begins. This preliminary coordination prevents transmission collisions while maintaining operational simplicity, as terminals simply follow the predetermined timing without complex independent sensing conflicts.
2Adaptability or versatility
If terminals use different carrier sensing methods, then adaptability to various signal conditions is improved, but transmission timing synchronization deteriorates leading to collisions
Solution Approach 1:
The invention merges the carrier sensing functions of multiple terminals into a coordinated process controlled by the base station. The base station determines a common transmission start timing that accounts for various signal conditions and notifies all terminals, thereby combining individual sensing adaptability with centralized timing synchronization to prevent collisions.
3Device complexity
If terminals calculate transmission timing independently, then device complexity is reduced, but transmission coordination worsens causing collisions in shared bandwidth
Solution Approach 1:
The base station acts as an intermediary that receives sensing information from terminals and determines a common transmission start timing. This intermediary approach maintains low terminal complexity while improving transmission coordination reliability, as the base station centralizes the complex timing calculation and synchronization functions.
Data Source
AI summary
A wireless communications system configured to use a predetermined bandwidth of an unlicensed bandwidth, the wireless communications system including: a base station configured to transmit a control signal that includes information indicating an offset time from a reference timing; and a terminal connected to the base station and configured to: receive the control signal from the base station; perform a process of detecting a wireless signal of the predetermined bandwidth in a standard period; and start transmission from a transmission start timing according to the offset time after no wireless signal of the predetermined bandwidth is detected in the process, the transmission start timing being a timing at which the terminal is allowed to start transmission of wireless signals.