Preemption Signal Interference Avoidance in Unlicensed Bands
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Solution Overview
Problem
In wireless communication systems using unlicensed bands, interference between various communication protocols is significant, leading to unpredictable quality of service and mobility issues due to shared channel access, which existing methods like LTE-U and LAA struggle to fully mitigate.
Innovation Solution
A method involving a transmission node sending a preemption signal using a narrow beam to a target reception node in the unlicensed band, with the option to switch to a wide beam if interference is detected, and using a processor to manage channel access and power allocation based on interference levels, ensuring effective interference avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If narrow beam is used for transmission in unlicensed band, then interference to other nodes is reduced, but channel access reliability deteriorates due to difficulty in detecting idle channels
Solution Approach 1:
The transmitting node performs Clear Channel Assessment (CCA) before transmitting the preemption signal to determine if the channel is idle. This preliminary channel sensing ensures that the narrow beam transmission only occurs when the channel is confirmed to be free, thereby maintaining channel access reliability while using narrow beams to reduce interference to other nodes.
Solution Approach 2:
The preemption signal acts as an intermediary between the transmitting node and target reception node. It is transmitted using a narrow beam to specifically notify the target node about upcoming data transmission, allowing the target node to prepare its receive beam without requiring wide channel sensing, thus reducing interference while maintaining reliable communication.
2Object-generated harmful factors
If preemption signal is transmitted using narrow beam, then interference avoidance is improved, but transmission complexity increases due to beam management
Solution Approach 1:
The preemption signal is transmitted using a narrow beam with specific directional properties tailored for the target reception node. This localized transmission approach concentrates energy in a specific direction, improving interference avoidance while the beam parameters are optimized for the specific communication scenario, reducing overall system complexity.
Solution Approach 2:
The preemption signal serves multiple functions: it notifies the target node of upcoming transmission, enables the target node to configure its receive beam, and reserves the channel for the transmitting node. This multi-functionality reduces the need for separate signaling messages and simplifies the overall beam management process.
3Measurement precision
If wide beam is used for channel sensing, then channel detection accuracy is improved, but interference to other communication nodes increases
Solution Approach 1:
The channel sensing process is segmented into two distinct phases: wide beam sensing for initial channel detection to determine if the channel is idle, and narrow beam transmission for actual data communication. This segmentation allows accurate channel detection while minimizing interference during the transmission phase by using directional narrow beams.
Solution Approach 2:
The transmitting node performs periodic Clear Channel Assessment (CCA) using wide beams before each preemption signal transmission to ensure the channel remains idle. This periodic sensing approach maintains accurate channel detection while limiting interference exposure to brief intervals, as narrow beams are used for the actual data transmission between sensing events.
Data Source
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AI summary
Provided is a communication method for interference avoidance in an unlicensed band. A transmission node transmits in the unlicensed band a preemption signal to a target reception node. Upon receiving a ready signal from the target reception node, the transmission node transmits in the unlicensed band a data signal to the target reception node. The preemption signal is transmitted by means of a narrow beam having substantially the same width and direction as the data signal.