Adaptive Modulation Orders for Unlicensed-Band Partial Subframes
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Solution Overview
Problem
In wireless communication systems operating in unlicensed bands, the use of partial subframes due to listen before talk procedures is inefficient, as the length of subframes is unpredictable and current methods do not effectively utilize these partial subframes for data transmission.
Innovation Solution
Adapt the modulation order based on whether a partial or complete subframe is available for transmission, adjusting the modulation scheme to optimize data transmission in both partial and complete subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If listen before talk procedure is employed in unlicensed bands, then channel access compliance is achieved, but subframe transmission time becomes unpredictable and inefficient
Solution Approach 1:
The patent applies dynamics by making the modulation order adaptive rather than fixed. The modulation order is dynamically selected based on the actual subframe length determined by the listen-before-talk procedure, allowing the system to adapt to variable transmission time conditions in unlicensed bands
Solution Approach 2:
The patent changes the modulation order parameter according to subframe length conditions. Different modulation orders are selected based on whether the subframe is short or long, optimizing transmission efficiency for each condition while maintaining compliance with listen-before-talk requirements
2Adaptability or versatility
If partial subframes are used due to listen before talk, then channel access flexibility is improved, but spectral efficiency deteriorates due to unpredictable subframe lengths
Solution Approach 1:
The patent changes the modulation order parameter based on subframe length to optimize spectral efficiency. By selecting appropriate modulation orders for different subframe conditions, the system maintains high productivity even with variable partial subframe lengths
Solution Approach 2:
The system dynamically adapts modulation parameters to match the actual transmission conditions in partial subframes, transforming the static modulation approach into a dynamic one that responds to channel access outcomes, thereby improving spectral efficiency while preserving channel access flexibility
Data Source
AI summary
A system includes a base station and a user equipment. The base station transmits, to the user equipment, downlink control information including an index indicating a first modulation order, a second modulation order, and a transport block size; and uses the second modulation order for a first transport block to be transmitted in a partial subframe, wherein the second modulation order is higher than the first modulation order which is used for a second transport block to be transmitted in a complete subframe of a defined length. The base station transmits the first transport block in the partial subframe to the user equipment. The user equipment receives, from the base station, the downlink control information including the index indicating the first modulation order, the second modulation order, and the transport block size, and receives, from the base station, the first transport block.