RLC Reordering for Fast RRC Connection Setup
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Solution Overview
Problem
In mobile communication systems, the existing methods for processing control information in UMTS networks face challenges in quickly completing RRC connection setups and preventing unnecessary standby of user equipment, leading to potential delays and reduced user experience due to the unreliable delivery of RRC connection setup messages over common channels.
Innovation Solution
The method involves using an RLC entity operating in unacknowledged mode with a receiving window and timer to reorder and reassemble protocol data units, ensuring reliable delivery of RRC messages by transmitting them multiple times and utilizing a re-ordering function to improve message reception success, even over common channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RRC connection setup messages are transmitted over common channels using existing methods, then the system maintains simplicity in message delivery, but the reliability of message delivery deteriorates due to potential loss and unnecessary standby
Solution Approach 1:
The transmitting side proactively transmits the same RRC message multiple times before the receiving side needs to process it. This preliminary repeated transmission ensures that the message is delivered reliably without requiring the receiving side to wait unnecessarily, thus improving both reliability and reducing delay.
Solution Approach 2:
The receiving side feeds back information about whether it has successfully received the RRC message to the transmitting side. Based on this feedback, the transmitting side can determine whether to continue transmitting the message or stop, thereby improving delivery reliability while avoiding unnecessary repeated transmissions and reducing overall delay.
2Productivity
If the transmitting side waits for acknowledgment before retransmitting RRC messages, then the system follows standard protocol procedures, but the connection setup speed deteriorates due to unnecessary standby time
Solution Approach 1:
The transmitting side performs preliminary repeated transmissions of the RRC message without waiting for acknowledgment. This preliminary action ensures that the message is already in the receiving side's buffer before the receiving side needs to process it, thereby improving connection setup speed while maintaining reliability through the re-ordering function.
Solution Approach 2:
The receiving side uses its own re-ordering function to automatically handle the reception and reassembly of RRC messages from multiple transmissions. This self-service mechanism ensures reliable message reception without requiring the transmitting side to wait for acknowledgments, thus improving connection setup speed while maintaining reliability.
3Reliability
If RRC messages are transmitted only once over common channels, then the transmission process remains simple and fast, but the reliability of message delivery deteriorates due to potential message loss
Solution Approach 1:
The transmitting side proactively transmits the same RRC message multiple times in advance. This preliminary repeated transmission improves delivery reliability by ensuring the message reaches the receiving side even if some transmissions are lost, while the re-ordering function automatically handles the complexity of processing these repeated messages.
Solution Approach 2:
The re-ordering function acts as an intermediary between the physical layer and higher layers. It automatically reassembles RRC messages from multiple repeated transmissions and presents them as complete messages to higher layers, thereby improving reliability without increasing the complexity visible to higher layers.
4Reliability
If the system uses acknowledged mode for RRC message transmission, then message delivery reliability improves through confirmation, but the connection setup time deteriorates due to waiting for acknowledgments and increased protocol overhead
Solution Approach 1:
The transmitting side proactively transmits the RRC message multiple times in unacknowledged mode before the receiving side needs to process it. This preliminary action ensures reliable delivery without requiring the receiving side to wait for acknowledgments, thus improving both reliability and reducing connection setup delay.
Solution Approach 2:
Instead of using acknowledged mode where the receiver sends acknowledgments back to the transmitter, this invention inverts the approach by having the transmitter proactively send multiple copies without waiting for acknowledgments. The receiver's re-ordering function automatically ensures reliable reception, thereby eliminating the time-consuming acknowledgment exchange while maintaining reliability.
Data Source
AI summary
A method of processing control information in a mobile communication system is disclosed, by which an RRC connection setup can be quickly completed and by which control information can be processed without an unnecessary standby of a mobile terminal. The present invention includes the steps of receiving a plurality of protocol data units transmitted plural time from a transmitting side via one common logical channel by an RLC (radio link control) entity operating in a UM (unacknowledged mode) and having a receiving window and a timer, reordering a plurality of the received protocol data units using sequence numbers of a plurality of the received protocol data units, the receiving window and the timer, reassembling at least one service data unit by processing a plurality of the re-ordered protocol data units, and delivering the at least one service data unit.