Unlicensed Spectrum Message Retransmission via Buffer Status
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Solution Overview
Problem
Interference in unlicensed spectrum usage occurs due to multiple devices attempting to communicate simultaneously, leading to co-channel interference and data collisions in LTE and WiFi systems.
Innovation Solution
A cell design integrating a LAA-LTE access point with a channel selector and scheduler that manages channel allocation and retransmissions efficiently, allowing for communication over both licensed and unlicensed bands, and includes features like hybrid automatic repeat request (HARQ) and dynamic timing settings to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple devices transmit simultaneously in unlicensed spectrum, then communication throughput increases, but interference and data collisions increase
Solution Approach 1:
The patent applies preliminary action by performing buffer status checks and initiating retransmissions before acknowledgment messages are received. The access point determines buffer emptiness in advance and proactively retransmits messages to prevent data loss, rather than waiting for collision detection or acknowledgment failures.
Solution Approach 2:
The system implements feedback mechanisms by monitoring buffer status and using acknowledgment messages to trigger retransmission decisions. The access point continuously checks buffer states and adjusts retransmission timing based on feedback from the network state and received acknowledgments.
2Reliability
If retransmission timing is delayed until acknowledgment receipt, then transmission accuracy improves, but transmission delay increases
Solution Approach 1:
The patent performs preliminary buffer status checks and initiates retransmissions before acknowledgment messages are received. This proactive approach reduces transmission delay while maintaining reliability by ensuring retransmissions occur during optimal time windows when the channel is likely still available.
Solution Approach 2:
The system dynamically adjusts retransmission timing based on buffer status and network conditions. Rather than using fixed retransmission intervals, the access point adapts retransmission decisions to current buffer states and channel conditions, optimizing the balance between accuracy and delay.
3Device complexity
If channel allocation is static, then device complexity decreases, but interference management capability worsens
Solution Approach 1:
The patent implements dynamic channel allocation where the access point continuously monitors buffer status and adjusts channel usage and retransmission timing based on current network conditions. This dynamic approach manages interference effectively without requiring complex manual configuration, as the system adapts automatically to changing conditions.
Data Source
AI summary
A method includes transmitting, at an access point configured to transmit data over an unlicensed band, a message to user equipment. The user equipment transmits to the access point an acknowledgement message indicating whether data provided within the message was successfully received in response to the message. The method further includes determining, at the access point, whether a buffer associated with the user equipment is empty. The method further includes retransmitting, from the access point to the user equipment, the message in response to determining the buffer of the user equipment is empty.