Contention Based Uplink Transmission Scheduling Overhead Reduction
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Solution Overview
Problem
The existing contention-based uplink transmission methods in LTE systems face challenges with high overhead and scheduling blocking due to the large overhead of CB Grants and difficulty in scheduling, which hinders the reduction of user plane delay.
Innovation Solution
Configuring a same CB-RNTI for multiple contention-based user groups and a single CB Grant with multiple schedule domains, where the CB Grant includes partial schedule information, allowing users to determine their allocated resources and transmit data without individual grants, thereby reducing the need for multiple CB Grants and lowering scheduling blocking probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple individual CB Grants are transmitted to different contention-based user groups, then each user group can be scheduled separately, but the overhead for transmitting CB Grants increases and scheduling blocking probability increases
Solution Approach 1:
The patent merges multiple CB Grants into a single unified CB Grant structure that can serve multiple contention-based user groups simultaneously. This is achieved by defining a CB Grant that contains multiple schedule domains, where each domain corresponds to a different user group identified by a CB-RNTI. Instead of transmitting separate CB Grants to each user group, the base station transmits one consolidated CB Grant that includes scheduling information for all user groups, thereby reducing overhead while maintaining individual scheduling capability.
Solution Approach 2:
The CB Grant structure is designed to be universal and multi-functional, capable of serving multiple contention-based user groups with different CB-RNTIs through a single grant message. The schedule domains within the CB Grant allow it to allocate resources for different user groups (e.g., uplink data transmission, uplink control information, random access preamble) simultaneously, making the CB Grant a universal scheduling instrument that eliminates the need for multiple specialized grants.
2Reliability
If multiple individual CB Grants are transmitted to different contention-based user groups, then each user group can be scheduled separately, but the PDCCH scheduling blocking increases and CB Grants become hard to schedule
Solution Approach 1:
By combining multiple CB Grants into one unified structure with multiple schedule domains, the patent reduces the total number of PDCCH transmissions required. Instead of sending separate PDCCH messages for each user group, the base station sends a single PDCCH carrying the consolidated CB Grant, which improves scheduling efficiency and reduces blocking probability while maintaining the ability to accurately schedule each user group through their respective schedule domains.
3Quantity of substance
If a single CB Grant with multiple schedule domains is used for multiple user groups, then overhead is reduced and scheduling efficiency improves, but the complexity of the CB Grant structure increases
Solution Approach 1:
The CB Grant structure is segmented into multiple schedule domains, where each domain is dedicated to a specific contention-based user group identified by a unique CB-RNTI. This segmentation allows the complex scheduling information to be organized in a structured and manageable way, with each domain containing relevant parameters for its corresponding user group. The segmentation approach makes the complexity tractable by dividing it into independent, identifiable sections rather than a monolithic structure.
Solution Approach 2:
The CB-RNTI serves as an intermediary that links each schedule domain to its corresponding contention-based user group. This intermediary mechanism simplifies the interpretation of the complex CB Grant structure by providing a clear mapping between schedule domains and user groups, allowing user equipment to identify and process only the relevant schedule domain corresponding to their CB-RNTI, thereby managing complexity through structured identification.
4Loss of time
If CB Grants are transmitted frequently to reduce user plane delay, then responsiveness improves, but the overhead and scheduling blocking increase
Solution Approach 1:
By merging multiple CB Grants into a single consolidated grant that serves multiple user groups, the patent enables more frequent scheduling updates without proportionally increasing overhead. The unified CB Grant structure allows the base station to efficiently allocate resources across multiple user groups in a single PDCCH transmission, reducing the per-scheduling-instance overhead and enabling more responsive user plane transmission with reduced delay while maintaining lower overall overhead compared to individual grants.
Data Source
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AI summary
A method and related apparatuses for Contention Based (CB) uplink transmission are provided by the present invention. And the method includes: configuring CB user group numbers and configuring a same CB Radio Network Temporary Identifier (CB-RNTI) for multiple CB user groups; for the multiple CB user groups having the same CB-RNTI, configuring a same CB Grant. With the present invention, it is not necessary to send a CB Grant for every CB user group, so that the resource overhead for CB Grant transmission is reduced, and thus the occurring probability of scheduling blocking is reduced.