Uplink Scheduling Method for Cellular Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LTE uplink scheduling methods face challenges in maximizing user transmissions due to limited control channel resources, power limitations, and the need to balance new data and retransmissions, while ensuring fairness and minimizing fragmentation losses.
Innovation Solution
A method for scheduling uplink transmission resources that spreads user transmissions over multiple subframes, prioritizes new data over retransmissions, and allocates resources to maximize spectral efficiency, ensuring a minimum resource guarantee for users and minimizing fragmentation by placing retransmissions at subframe edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of users scheduled per subframe is increased to maximize spectral efficiency, then the control channel resources become overloaded and cannot transmit all necessary scheduling grants
Solution Approach 1:
The patent segments the scheduling process into two parts: first determining the number of users to schedule (which may be less than the actual number of users with data), and second determining which specific users to schedule. This segmentation allows the system to manage control channel resources efficiently by not always transmitting grants for all users, thereby resolving the contradiction between maximizing spectral efficiency and maintaining control channel capacity.
2Reliability
If retransmissions are scheduled immediately after initial transmission, then the time between transmission and retransmission is fixed as required by synchronous HARQ, but the control channel resources are consumed and cannot be reused
Solution Approach 1:
The patent applies preliminary action by determining the number of users to schedule in advance, before actually transmitting the scheduling grants. This allows the system to pre-calculate the optimal number of users based on control channel capacity, ensuring that sufficient resources are allocated for both initial transmissions and subsequent retransmissions without overloading the control channel.
3Device complexity
If the number of scheduling grants transmitted is limited to fit control channel capacity, then fewer users can be scheduled per subframe, but this reduces spectral efficiency
Solution Approach 1:
The patent implements dynamics by making the number of users to schedule variable and adaptive rather than fixed. The system dynamically determines the optimal number of users based on current control channel capacity, user priorities, and data availability, allowing flexible adjustment between the number of users scheduled and the control channel resources consumed, thereby resolving the contradiction between resource limitations and spectral efficiency.
4Productivity
If all users with data are scheduled immediately, then the number of active transmissions increases, but fragmentation losses increase and fairness among users deteriorates
Solution Approach 1:
The patent applies local quality by treating different users differently based on their specific characteristics and needs. Instead of uniform scheduling, the system considers individual user priorities, data buffer status, and channel conditions to determine the optimal subset of users to schedule, thereby achieving both high spectral efficiency and fairness among users with different requirements.
Data Source
AI summary
A method (1000) for scheduling uplink transmission resources such as transmission duration and frequency to users (120) in a cell (110) of a cellular system (100). Grants for the use of uplink transmission resources are sent (1005) on a downlink control channel to users in the cell and the users' uplink transmissions are sent (1010) in subframes which have a certain extension in time and frequency. For each of at least a number of subframes, a decision (1015) is made on the number of users that will be scheduled resources for uplink transmission in the subframe, so that said number of users is maximized (1020) with respect to the control channel's capacity to transmit uplink grants for that subframe.