Wireless Device Transmission Scheduling in Unlicensed Spectrum
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Solution Overview
Problem
Current multicarrier communication systems face challenges in efficiently managing carrier aggregation, especially in scenarios requiring high data rates and seamless mobility, where the increasing demand for data traffic necessitates more spectrum, and the use of unlicensed spectrum to complement licensed spectrum is becoming essential.
Innovation Solution
The implementation of Licensed Assisted Access (LAA) technology, which employs listen-before-talk procedures for fair coexistence with other unlicensed spectrum users, and adaptive energy detection thresholds to dynamically manage channel access, along with multi-subframe grants for efficient uplink HARQ operations, enables efficient use of unlicensed spectrum while maintaining compatibility with licensed spectrum operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented to increase data rates, then network capacity and data throughput are improved, but system complexity and interference management difficulty increase
Solution Approach 1:
The patent segments the uplink transmission by dividing it into multiple parts: initial transmission in licensed spectrum, and subsequent transmissions in unlicensed spectrum. This segmentation allows the system to leverage both licensed and unlicensed spectrum resources while managing complexity through structured, phased transmission approaches.
Solution Approach 2:
The patent introduces licensed spectrum as an intermediary resource that facilitates reliable HARQ feedback transmission. By using licensed spectrum for initial transmissions and control signaling, the system mediates between the reliability requirements of HARQ and the capacity benefits of unlicensed spectrum, reducing overall system complexity.
2Productivity
If unlicensed spectrum is used to complement licensed spectrum, then network capacity increases, but interference from other unlicensed spectrum users increases
Solution Approach 1:
The patent implements dynamic spectrum access by monitoring channel conditions and adapting transmission behavior. The system dynamically switches between licensed and unlicensed spectrum based on channel availability, interference levels, and HARQ feedback requirements, optimizing network capacity while managing interference through adaptive resource allocation.
Solution Approach 2:
The patent employs HARQ feedback mechanisms where the receiver sends acknowledgments about received packets. This feedback loop allows the transmitter to adapt to channel conditions and interference levels in real-time, adjusting retransmission strategies and spectrum selection to maintain high network capacity while minimizing interference impact.
3Productivity
If HARQ feedback is transmitted reliably over unlicensed spectrum, then data transmission efficiency improves, but channel access conflicts and interference increase
Solution Approach 1:
The patent segments the control signaling (HARQ feedback) from data transmission by initially using licensed spectrum for reliable feedback exchange. This segmentation ensures that critical control information is transmitted with high reliability while data transmissions can utilize unlicensed spectrum resources, reducing channel access conflicts for control signaling.
Solution Approach 2:
The patent uses licensed spectrum as an intermediary channel for HARQ feedback transmission. By mediating the feedback process through the more reliable licensed spectrum, the system achieves reliable transmission efficiency while minimizing channel access conflicts that would occur if all feedback were transmitted over contested unlicensed spectrum.
Data Source
AI summary
A wireless device receives a downlink control information comprising: a first field indicating a number of scheduled time intervals; a modulation and coding scheme field; a transmit power control field; and a listen before talk (LBT) field indicating timing information for performing an LBT procedure. The LBT procedure for transmission in the number of scheduled time intervals is performed based on the timing information. A transmission power of each time interval in the number of scheduled time intervals is determined based on a same closed loop adjustment factor and the transmit power control field, wherein the transmission power of each time interval of the number of scheduled time intervals is adjusted in response to a total transmit power for a respective time interval exceeding a power value. The wireless device transmits, in each time interval of number of scheduled time intervals, employing the modulation and coding scheme field.