Grant-Free Uplink Link Adaptation for Wireless Systems
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Solution Overview
Problem
Wireless networks face inefficiencies due to high signaling resource overhead and latency in grant-based scheduling mechanisms, especially for small data transmissions, which can consume up to 30-50% of the packet size and introduce initial delays of 7-8 ms.
Innovation Solution
Implementing a grant-free uplink transmission scheme with link adaptation, where a base station determines resource overloading and sets a modulation and coding scheme (MCS) limit for contention transmission units (CTUs), allowing user equipment (UEs) to adapt their MCS levels within the limit based on local conditions, reducing the need for explicit resource requests and grants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If grant-based scheduling mechanism is used for uplink transmission, then resource allocation control is improved, but signaling resource overhead increases to 30-50% of packet size
Solution Approach 1:
The patent extracts the scheduling request and grant signaling elements from the transmission process by implementing grant-free uplink access. UEs are pre-configured with uplink resources and can transmit data immediately without requesting scheduling grants, removing the problematic signaling overhead while preserving resource allocation control through pre-configuration.
Solution Approach 2:
The patent applies preliminary action by pre-configuring uplink resources and modulation and coding scheme (MCS) limits for UEs before data transmission. This allows UEs to transmit data immediately without real-time scheduling requests, as all necessary parameters are predetermined and available in advance.
2Ease of operation
If grant-based scheduling mechanism is used for uplink transmission, then resource allocation control is improved, but transmission delay increases to 7-8 ms
Solution Approach 1:
The patent applies preliminary action by pre-configuring uplink resources and modulation and coding scheme (MCS) limits for UEs before data transmission. This allows UEs to transmit data immediately without real-time scheduling requests, as all necessary parameters are predetermined and available in advance, reducing latency to near-zero.
Solution Approach 2:
The patent removes the scheduling request and grant signaling elements from the transmission process. By implementing grant-free uplink access where UEs can transmit data immediately on pre-configured resources, the patent eliminates the 7-8 ms delay inherent in traditional grant-based scheduling.
3Productivity
If MCS limit is set based on resource overloading for CTU access region, then system capacity is improved, but transmission reliability may deteriorate
Solution Approach 1:
The patent applies dynamics by making the MCS limit adaptive rather than fixed. The base station determines the MCS limit dynamically based on the measured resource overloading condition in each CTU access region. When overloading is high, the MCS limit is reduced to maintain reliability; when overloading is low, the MCS limit is increased to maximize capacity. This dynamic adjustment resolves the contradiction between capacity and reliability.
Solution Approach 2:
The patent changes the MCS parameter based on resource overloading conditions. The base station monitors the number of UEs accessing each CTU access region and adjusts the MCS limit accordingly. This parameter adaptation allows the system to optimize the trade-off between transmission capacity and reliability in real-time based on actual network conditions.
Data Source
AI summary
A BS determines an amount of resource overloading for a contention transmission unit (CTU) access region associated with a grant-free uplink transmission scheme in a multiple access system. The BS determines a modulation and coding scheme (MCS) limit indicating a maximum MCS level for the CTU access region. The BS sends the MCS limit to a plurality of user equipments (UEs) associated with the first CTU access region. A UE receives from the base station the MCS limit and determines a first MCS index within the MCS limit for a first uplink transmission. The UE sends the first uplink transmission to the base station using a CTU in the CTU access region. The first uplink transmission includes user data and the first MCS index determined at the first UE.