Mobile Station ACK/NACK Control Message Prioritization
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Solution Overview
Problem
In EGPRS communication systems, the reliability of acknowledgment information received via piggy-backed PAN fields is lower than that received via separate packet ACK/NACK control messages, leading to unnecessary retransmissions of data blocks in a TENTATIVE_ACK state, which can stall the transmit window even if the blocks have been successfully received.
Innovation Solution
A mobile station prioritizes transmissions by sending a separate packet downlink ACK/NACK control message instead of retransmitting data blocks in a TENTATIVE_ACK state when polled for acknowledgment, allowing the network to advance its transmit window without requiring confirmation from separate ACK/NACK control messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If acknowledgment information is transmitted via piggy-backed PAN fields to reduce latency, then transmission speed is improved, but reliability of acknowledgment information deteriorates
Solution Approach 1:
The system dynamically adjusts the acknowledgment transmission method based on the state of data blocks. When data blocks are in TENTATIVE_ACK state, the system switches from using PAN fields to using separate ACK/NACK control messages, thereby adapting the reliability of acknowledgment transmission to the current system state.
Solution Approach 2:
The invention changes the parameter of acknowledgment transmission reliability by selecting different transmission methods (PAN field vs. separate control message) based on the acknowledgment state. This parameter change ensures that when reliability is needed (TENTATIVE_ACK state), the more reliable separate control message method is used.
2Reliability
If data blocks in TENTATIVE_ACK state are retransmitted to ensure reliability, then reliability is improved, but unnecessary retransmissions occur causing loss of time
Solution Approach 1:
The system uses feedback from the acknowledgment state (TENTATIVE_ACK vs. confirmed ACK) to determine whether retransmission is necessary. When a separate ACK/NACK control message confirms the acknowledgment, the system stops retransmission, avoiding unnecessary time loss while maintaining reliability.
Solution Approach 2:
The retransmission behavior is made dynamic based on the acknowledgment confirmation state. The system transitions from retransmitting data blocks in TENTATIVE_ACK state to stopping retransmission when confirmation is received, thereby eliminating unnecessary retransmissions and time loss.
3Reliability
If separate ACK/NACK control messages are used to confirm acknowledgment, then reliability is improved, but transmission latency increases
Solution Approach 1:
The system uses periodic separate ACK/NACK control messages to confirm acknowledgment information that was initially transmitted via PAN fields. This periodic confirmation mechanism ensures reliability while minimizing latency by only using separate messages when necessary for confirmation.
Solution Approach 2:
The system performs preliminary acknowledgment transmission via PAN fields to reduce latency, then follows up with separate ACK/NACK control messages for confirmation. This preliminary action approach allows the system to achieve low latency initially while maintaining reliability through subsequent confirmation.
Data Source
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AI summary
Methods and apparatus to prioritize mobile station transmissions in response to network acknowledgment polling are disclosed. An example method in a mobile station (105) disclosed herein comprises receiving a request (206) for acknowledgment information expected to be transmitted with data, and transmitting a control message (214) in response to the request (206) if a previously transmitted data block is associated with a tentative acknowledgment state, the control message including acknowledgment information.