LAA-LTE Clear Channel Assessment Backoff Adjustment
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Solution Overview
Problem
In Licensed-Assisted Access Using Long Term Evolution (LAA-LTE) systems, devices face a high probability of collision when preempting unlicensed spectra, leading to recurring data transmission collisions with other devices like WiFi, as existing methods lack effective prevention mechanisms.
Innovation Solution
A data transmission method that adjusts the initial backoff value of clear channel assessment (CCA) in the unlicensed spectrum by randomly increasing or decreasing a variable value, and adjusts the detection moment or quantity of CCA, allowing devices to stagger data transmission and change competition dynamics, thereby reducing collision reoccurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If devices use traditional LBT methods (LBE or FBE operation modes) to access unlicensed spectrum, then channel access can be achieved, but collision probability increases and collision reoccurrence cannot be prevented
Solution Approach 1:
The patent dynamically adjusts the initial backoff value based on collision detection results. When a collision is detected, the device modifies its backoff behavior by randomly increasing or decreasing the initial backoff value, transforming the static LBT parameter into a dynamic adaptive parameter that responds to channel conditions and collision events.
Solution Approach 2:
The patent implements a feedback mechanism where the device monitors channel occupancy and detects collisions during data transmission. Based on this feedback information, the device adjusts its subsequent backoff behavior, creating a closed-loop control system that learns from past collisions and adapts to prevent future collisions.
2Productivity
If devices transmit data simultaneously in unlicensed spectrum without coordination, then transmission opportunities increase, but collision frequency increases
Solution Approach 1:
The patent changes the backoff parameter values dynamically based on collision events. By randomly increasing or decreasing the initial backoff value after detecting a collision, the system modifies the timing parameters of channel access, thereby spreading out transmission opportunities and reducing the probability of simultaneous transmissions that cause collisions.
3Ease of operation
If devices use fixed backoff values for channel access, then access behavior is predictable, but collision reoccurrence cannot be prevented
Solution Approach 1:
The patent transforms the fixed backoff value into a dynamic parameter that changes based on collision events. The initial backoff value is randomly adjusted (increased or decreased) when collisions are detected, making the access behavior adaptive rather than static, thereby preventing collision reoccurrence while maintaining operational simplicity.
Data Source
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AI summary
Embodiments of the present invention relate to the communications field, and provide a data transmission method and an apparatus, to effectively reduce a collision reoccurrence probability after a device in an LAA-LTE system preempts an unlicensed spectrum and collides with another device. A first device adjusts a detection moment or a quantity of detection times of clear channel assessment CCA of a channel in an unlicensed spectrum after the first device determines that the first device collides with another device when occupying the channel in the unlicensed spectrum to transmit data, and the first device occupies, according to an adjusted detection moment or an adjusted quantity of detection times of clear channel assessment CCA of the channel in the unlicensed spectrum, the channel in the unlicensed spectrum to transmit data. The data transmission method and the apparatus are applied to data transmission.