Contention-Based Uplink Transmission State Transition
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Solution Overview
Problem
In wireless communication systems, the transition from a dormant state to an active state for uplink transmission is delayed due to the need for a scheduling request (SR) transmission, which increases the transition time and does not meet the requirements of 3GPP LTE-Advanced for a transition time of less than or equal to 10 ms.
Innovation Solution
A contention-based uplink transmission method is implemented, where user equipment (UE) can transition to an active state without SR transmission by sending a contention-based uplink signal, receiving a UL grant, and transitioning based on acknowledgment (ACK)/non-acknowledgment (NACK) from the base station, allowing for immediate data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scheduling request (SR) transmission is used for state transition, then the transition process is controlled and reliable, but the transition time increases beyond 10 ms requirement
Solution Approach 1:
The UE performs preliminary actions by monitoring PDCCH for UL grant in dormant state and prepares transmission resources in advance. The base station pre-configures uplink resources and monitors for contention-based signals, enabling faster state transition without SR transmission delay.
Solution Approach 2:
The invention extracts and removes the SR transmission step from the state transition process. By allowing direct contention-based uplink transmission without SR, the patent eliminates the waiting time for SR opportunity while maintaining reliable state transition through UL grant-based acknowledgment.
2Device complexity
If SR transmission is required for uplink transmission, then resource allocation is controlled, but the system responsiveness and efficiency decrease
Solution Approach 1:
The UE performs self-service by autonomously selecting and transmitting on pre-configured uplink resources without requiring SR permission. The base station provides resource pools in advance, and UEs independently access them based on contention resolution, eliminating SR overhead while maintaining controlled resource allocation.
Solution Approach 2:
The uplink resources configured for contention-based transmission serve multiple functions: they can be used for data transmission, acknowledgment response, and state transition signaling. This multi-functionality eliminates the need for separate SR mechanisms while maintaining resource allocation control.
Data Source
AI summary
The present invention provides a method and apparatus for performing contention-based uplink transmission in a wireless communication system. A terminal transmits a contention-based uplink signal to a base station. The base station detects a contention-based uplink signal that is transmitted from at least one terminal, and determines whether there exists a terminal corresponding to the detected contention-based uplink signal. The terminal receives an uplink (UL) grant from the base station. The terminal switches from a dormant station into an active state, based on the uplink grant. Here, the dormant state is a state where radio resource control connection is formed between the base station and the terminal but data is not actually transmitted, and the active state is a state where data transmission is actually performed.