Grant-Free Scheduling via Large-Scale Fading Classification
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Solution Overview
Problem
Conventional mobile communication systems face challenges in predicting channel performance between user terminals and base stations, leading to inaccurate scheduling, decreased spectral efficiency, and increased delays due to the need for frequent reference signal transmissions and channel information acquisition in massive MIMO environments.
Innovation Solution
A scheduling method that classifies user terminals into groups based on large-scale fading information, sets transmission power and scheduling periods, and allocates resource elements without requiring reference signals or immediate channel state information, allowing for grant-free multiple access and reduced latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional scheduling with reference signal transmission is used, then channel information can be acquired for user scheduling, but spectral efficiency decreases and delays increase
Solution Approach 1:
The patent extracts and removes the reference signal transmission step from the conventional scheduling process. By using grant-free uplink transmission where user terminals transmit data directly without prior scheduling, the system eliminates the need for reference signals while still achieving effective channel information acquisition through the data transmission itself, thereby resolving the contradiction between measurement precision and spectral efficiency
Solution Approach 2:
The patent implements preliminary classification of user terminals into groups based on large-scale fading information before transmission. This preliminary action allows the base station to pre-configure resource allocations and scheduling parameters, enabling direct uplink transmission without requiring real-time reference signals during the scheduling process, thus improving spectral efficiency while maintaining adequate channel knowledge
2Measurement precision
If reference signals are transmitted before scheduling, then channel information can be obtained, but energy efficiency of user terminals decreases
Solution Approach 1:
The patent removes the separate reference signal transmission step that consumes user terminal energy. Instead, user terminals transmit only their data signals directly to the base station using grant-free access. The base station extracts channel information from these data transmissions, thereby eliminating unnecessary energy consumption at user terminals while maintaining channel information availability
Solution Approach 2:
The system enables user terminals to transmit data directly without requiring energy-consuming reference signal transmissions. The base station performs self-service by extracting channel information from the incoming data transmissions and autonomously performing scheduling decisions, eliminating the need for user terminals to expend additional energy on reference signal generation and transmission
3Measurement precision
If uplink reference signals are transmitted before scheduling, then channel estimation can be performed, but transmission delays increase due to uplink-downlink conversions
Solution Approach 1:
The patent performs preliminary classification of user terminals into groups based on large-scale fading information before the transmission occurs. This pre-processing allows the base station to prepare resource allocations and scheduling decisions in advance, enabling direct uplink data transmission without requiring subsequent downlink scheduling commands, thereby eliminating the time-consuming uplink-downlink conversion cycles
Solution Approach 2:
The patent removes the sequential uplink reference signal transmission and downlink scheduling command exchange from the process. By implementing grant-free uplink access, user terminals transmit data directly, and the base station performs channel estimation and scheduling autonomously based on pre-acquired large-scale fading information, eliminating the time delay associated with multiple uplink-downlink conversions
Data Source
AI summary
A scheduling apparatus and method are disclosed. An embodiment of the invention provides a scheduling apparatus that includes: a scheduling group classification unit that classifies user terminals located within a serving cell of a base station into a multiple number of scheduling groups by using large-scale fading information of the user terminals; a transmission power setting unit that sets the transmission power of the user terminals for each of the classified scheduling groups; a scheduling period setting unit that sets the scheduling period for each of the scheduling groups by determining a resource element usage proportion for each of the scheduling groups based on the data rate of each of the scheduling groups and determining the data rate expected for all user terminals; and a resource element allocation unit that allocates resource elements used for each of the scheduling groups according to each of the determined scheduling periods.