LTE Scheduling via User-Rate Matrix and Dynamic Transmission Mode Selection
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Solution Overview
Problem
Current scheduling systems in LTE networks fail to efficiently allocate resource blocks to multiple users using MU-MIMO, as they restrict each user to a single transmission mode across all resource blocks and do not adapt modulation and coding schemes based on varying channel quality indicators.
Innovation Solution
A method is introduced to generate a user-rate matrix for each base station, sorting transmission modes by achievable rate and allocating resource blocks based on a scheduling list that considers spatial multiplexing, transmit diversity, and multi-user MIMO modes, while adapting modulation and coding schemes to optimize throughput and quality of service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single transmission mode is selected per user per TTI, then device complexity is reduced and ease of operation is improved, but network throughput and resource allocation efficiency deteriorate
Solution Approach 1:
The patent segments the resource allocation process by creating separate transmission mode selections for different resource block groups within a TTI. Instead of selecting one mode for all RBs, the system divides RBs into multiple groups and allows different transmission modes (spatial multiplexing, transmit diversity, or MU-MIMO) for each group, thereby increasing throughput without significantly complicating the operation.
Solution Approach 2:
The patent introduces dynamic transmission mode selection where the transmission mode can change across different resource block groups within the same TTI based on channel conditions and QoS requirements. This dynamic approach allows the system to adapt to varying channel qualities and optimize throughput while maintaining manageable complexity through structured decision-making.
2Device complexity
If the same modulation and coding scheme is used across all resource blocks allocated to a user, then device complexity is reduced, but network throughput and adaptability to varying channel conditions deteriorate
Solution Approach 1:
The patent applies local quality by allowing different modulation and coding schemes (MCS) to be used for different resource block groups allocated to the same user, based on the specific channel quality indicators of each group. This enables the system to use higher-order modulations for good channel conditions and more robust schemes for poor conditions, thereby optimizing throughput without requiring full per-RB adaptation.
3Speed
If resource blocks are allocated without considering quality of service requirements, then allocation speed is improved, but service quality and user experience deteriorate
Solution Approach 1:
The patent implements preliminary action by pre-classifying resource blocks into groups and pre-determining transmission modes and MCS for each group based on channel quality indicators before final allocation. This preliminary preparation allows the scheduler to quickly match users to appropriate RB groups while considering QoS requirements, thereby maintaining fast allocation speed while ensuring service quality.
4Device complexity
If channel feedback overhead is reduced, then system complexity and signaling overhead are reduced, but scheduling accuracy and performance deteriorate
Solution Approach 1:
The patent applies partial action by implementing a simplified channel feedback mechanism that collects essential channel quality indicators for resource block groups rather than full per-subcarrier channel state information. This partial feedback approach reduces signaling overhead and complexity while providing sufficient accuracy for the transmission mode selection and MCS determination needed for optimized throughput.
Data Source
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AI summary
A method to be carried out in a wireless communication network comprising at least one base station associated to a corresponding area for transmitting/receiving data to/from corresponding user terminals located within said area is disclosed. The method comprises generating a user-rate matrix for each base station. Each element of the user-rate matrix provides a corresponding score, in terms of achievable rate, to a user terminal or to a group of user terminals located within the corresponding area when a transmission is made to/from said user terminal or said group of user terminals, respectively, from/to the base station by employing a selected transmission mode among a set of predetermined transmission modes. The method further comprises processing the elements of the user-rate matrix in order to create a scheduling list where the elements are sorted by a decreasing score, and associating to each user terminal a corresponding selected transmission mode based on the scheduling list for the transmission/reception of data to/from the base station. Said set of predetermined transmission modes includes at least a spatial multiplexing transmission mode, a transmit diversity transmission mode and a multi-user multiple-input multiple-output transmission mode.