Grant-Free Wireless Uplink Mode Switching for Contention
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Solution Overview
Problem
In wireless communication systems, especially in 5G networks, the grant-free transmission mode faces challenges with resource contention and decoding performance degradation due to the lack of centralized scheduling, leading to collisions and data packet loss, especially when the number of users increases rapidly.
Innovation Solution
A method where the base station evaluates the decoding performance of uplink transmissions and switches user terminals from a grant-free mode to a grant mode when the decoding performance falls below a threshold, allowing for more accurate resource management and reduced contention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grant-free transmission mode is used to support massive machine type communication, then device access efficiency and energy consumption are improved, but resource contention and decoding performance degradation occur when user density increases
Solution Approach 1:
The system dynamically switches between grant-free mode and grant mode based on user density conditions. When user density exceeds a threshold, the base station transitions affected user terminals from grant-free mode to grant mode, thereby adapting the transmission mode to current system conditions and resolving the contradiction between access efficiency and decoding performance.
Solution Approach 2:
The system changes the operational parameter (transmission mode) of user terminals from grant-free to grant mode based on user density. This parameter change allows the system to maintain high access efficiency for low-density scenarios while ensuring reliable decoding performance in high-density scenarios.
2Loss of time
If grant-free transmission mode is used to enable direct data transmission, then scheduling overhead is reduced, but resource contention and data packet loss increase due to lack of centralized scheduling
Solution Approach 1:
The system dynamically adjusts the transmission mode based on user density conditions. In low-density scenarios, grant-free mode is maintained to minimize scheduling overhead. In high-density scenarios, the system switches to grant mode to reduce resource contention and data packet loss, thereby dynamically balancing the trade-off between scheduling overhead and packet loss.
Solution Approach 2:
The base station acts as an intermediary that monitors user density and controls the transmission mode switching. When user density exceeds the threshold, the base station intervenes by switching user terminals from grant-free to grant mode, thereby preventing resource contention and data packet loss that would otherwise occur in pure grant-free operation.
3Device complexity
If grant-free mode is used for uplink transmission, then system complexity is reduced, but decoding performance deteriorates when the number of users suddenly increases
Solution Approach 1:
The system maintains low complexity by default through grant-free mode but dynamically switches to grant mode when user density exceeds the threshold. This dynamic approach allows the system to keep complexity low during normal operation while ensuring reliable decoding performance when user density suddenly increases.
Solution Approach 2:
The system uses self-service mechanisms where user terminals continue to operate in grant-free mode without requiring base station scheduling, thereby maintaining low system complexity. When user density exceeds the threshold, the base station intervenes to switch specific terminals to grant mode, providing selective service enhancement without increasing overall system complexity significantly.
Data Source
AI summary
The present invention relates to a wireless communication method and device based on a license-free band. A method for wireless communication between a base station and a user terminal comprises: receiving uplink transmission from a first type user terminal, the first type user terminal operating in a license-free mode; and switching at least one first type user terminal to a licensed mode if the evaluated decoding performance of the uplink transmission does not reach a desired level. The decoding performance is an indicator capable of more accurately reflecting the degree of resource contention, and thus can more reasonably determine the time of switching the user terminal to the licensed mode.