Unlicensed Band Transmission Timing Shift for LTE-LAA
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Solution Overview
Problem
The existing LTE-LAA technology limits the transmission opportunity to twice per subframe in Unlicensed bands, which can degrade throughput due to the restrictive subframe timing and carrier sensing methods, leading to inefficient data transmission in 4G and anticipated 5G wireless communication systems.
Innovation Solution
A transmission device that shifts the timing of control and shared channels in Unlicensed bands, allowing data transmission across multiple symbols within a slot, including the use of Cross-TTI (Cross-TTI) to transmit remaining data without waiting for ACK or NACK, thereby increasing transmission opportunities and reducing processing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE-LAA uses subframe timing for transmission in Unlicensed bands, then transmission timing is standardized and synchronized, but transmission opportunity is confined to only twice per subframe
Solution Approach 1:
The patent segments the transmission opportunity into multiple parts by allowing transmissions at both the head symbol and the middle symbol (eighth symbol from head) of the subframe. This segmentation enables the transmission side to utilize more time resources within the same subframe structure, increasing transmission opportunities from twice to potentially more frequent transmissions without changing the fundamental subframe timing structure.
Solution Approach 2:
The patent introduces dynamic selection of transmission timing within the subframe structure. By specifying that transmission can occur at both head symbol and middle symbol positions, the system dynamically adapts transmission opportunities based on channel conditions and scheduling requirements, rather than being fixed to a single timing position.
2Productivity
If LTE-LAA transmits data at half the timing of a subframe, then transmission opportunity increases, but the amount of data in each transport block is reduced to half
Solution Approach 1:
The patent employs periodic transmission opportunities at regular intervals within the subframe - specifically at the head symbol and middle symbol positions. This periodic structure allows the system to transmit multiple smaller transport blocks at different time points rather than waiting for larger blocks, effectively distributing data transmission across multiple periodic opportunities.
Solution Approach 2:
By establishing predetermined transmission timing positions (head symbol and middle symbol) in advance, the system prepares multiple transmission opportunities beforehand. This allows the transmission side to efficiently utilize available channel conditions at these pre-planned time points without requiring complex real-time scheduling decisions.
3Reliability
If LTE-LAA uses carrier sensing before transmission, then channel access is fair and coexistence with other networks is improved, but transmission delay increases due to waiting for channel availability
Solution Approach 1:
The patent performs carrier sensing in advance at multiple predetermined time points within the subframe (at head symbol and middle symbol positions). By preparing and checking channel availability at these pre-planned time points, the system reduces the uncertainty and delay associated with waiting for channel access, as the transmission opportunities are already identified and scheduled.
Solution Approach 2:
The patent maintains continuous channel monitoring and transmission readiness by having multiple transmission opportunities within the subframe. Instead of a single transmission attempt followed by waiting, the system continuously checks and transmits at multiple points, reducing idle time and maintaining more continuous useful transmission action.
Data Source
AI summary
A transmission device, which is capable of wirelessly communicating with a reception device by using a first frequency band that does not need a license, the transmission device including, a controller configured to verify whether the first frequency band is not used by other transmission devices, and shift, in a time direction, a first symbol including a first control channel and a first shared channel in a first communication direction, or a second symbol including a second shared channel in a second communication direction different from the first communication direction, and a transmitter configured to transmit, to the reception device, a first control signal and first data, which are allocated to the first symbol, by using the first control channel and the first shared channel, respectively, or second data allocated to the second symbol by using the second shared channel.