Mobile Terminal State Transition Control via RLC Feedback
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Solution Overview
Problem
In UMTS mobile communication systems, unnecessary state transitions in mobile terminals lead to wastage of radio resources and delayed transmission due to frequent changes from CELL_PCH to CELL_FACH states, even when downlink data is rarely received.
Innovation Solution
A method for mobile terminals to determine whether to stay in the CELL_PCH state or transition to the CELL_FACH state based on response messages, such as RLC ACK or NACK, to minimize state transitions and conserve radio resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile terminal frequently transitions between CELL_PCH and CELL_FACH states to respond to downlink data, then the response reliability is improved, but the radio resource waste and transmission delay increase
Solution Approach 1:
The patent implements a feedback mechanism where the mobile terminal sends response messages (RLC ACK/NACK) to the network based on downlink data reception status. The network uses this feedback to determine whether to maintain or change the terminal's state, eliminating the need for frequent state transitions. The terminal stays in CELL_PCH state and only transitions to CELL_FACH when actually needed, as determined by the network based on feedback information.
2Speed
If the mobile terminal transitions to CELL_FACH state for every downlink data reception, then the data transmission speed is improved, but the transmission delay increases due to frequent state changes
Solution Approach 1:
The patent prepares the terminal for potential data transmission by maintaining it in CELL_PCH state with DRX (Discontinuous Reception) enabled, allowing it to wake up at predetermined intervals to check for downlink data. This preliminary preparation allows the terminal to quickly transition to CELL_FACH only when data is actually present, rather than transitioning for every possible data event, thus reducing unnecessary state change delays.
3Use of energy by moving object
If the mobile terminal uses DRX method to minimize power consumption, then the energy efficiency is improved, but the ability to receive downlink data continuously deteriorates
Solution Approach 1:
The patent dynamically adjusts the terminal's operational state based on actual data reception needs. The terminal operates in DRX mode within CELL_PCH state, dynamically switching between sleeping and active states. When downlink data is detected, the terminal dynamically transitions to CELL_FACH state for data transmission, then returns to CELL_PCH. This dynamic state management allows the terminal to maintain low power consumption while still being able to receive data when needed.
Data Source
AI summary
In a wireless mobile communications system, a state transition method of a mobile terminal is provided. The mobile terminal receives downlink data in a first state of the mobile terminal, a state of the mobile terminal keeps in the first state or transits to a second state based on a response message responding to the received downlink data, thereby minimizing an unnecessary state transition of the mobile terminal.