Uplink Resource Request Prioritization in LTE Mobile Terminals
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Solution Overview
Problem
In LTE systems, mobile terminals face challenges in requesting uplink resources during continuous downlink transmissions and repeated ACK/NACK transmissions, leading to potential D-SR failures and delayed uplink data transmission, especially in TDD scenarios where uplink subframes are limited.
Innovation Solution
Prioritizing preamble transmission and at least one message of the random access procedure, such as Msg3, relative to repeated ACK/NACK transmissions to facilitate uplink resource requests even during continuous downlink transmissions, thereby reducing the likelihood of D-SR failures and enabling timely uplink data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile terminal transmits repeated ACK/NACK on PUCCH during continuous downlink transmission, then the PUCCH performance is improved, but the mobile terminal cannot transmit scheduling request to request uplink grant
Solution Approach 1:
The system dynamically adjusts transmission priorities based on the state of downlink transmissions and ACK/NACK repetition configuration. When ACK/NACK repetition is configured and downlink transmissions are continuous, the system dynamically allows scheduling request transmission despite the repetition configuration, creating a dynamic exception handling mechanism that adapts to real-time transmission conditions.
2Reliability
If the mobile terminal waits for downlink transmission to complete before transmitting scheduling request, then ACK/NACK repetition can be completed, but uplink resource request is delayed
Solution Approach 1:
The mobile terminal performs preliminary assessment of transmission conditions before initiating scheduling request. When the terminal detects that ACK/NACK repetition is configured but downlink transmission continuity is interrupted or will be interrupted, it proactively transmits the scheduling request in advance rather than waiting for the downlink transmission to complete, thereby preventing time loss while maintaining transmission reliability.
3Reliability
If the scheduling request counter is increased due to failed transmission during ACK/NACK repetition, then transmission attempts are tracked, but D-SR failure occurs and random access procedure is triggered
Solution Approach 1:
The system changes the decision parameter for scheduling request transmission by introducing a new condition: when ACK/NACK repetition is configured but downlink transmission is not continuous (gaps exist), the terminal modifies its behavior to allow scheduling request transmission. This parameter change prevents unnecessary counter increments and avoids triggering random access procedures, thereby maintaining uplink resource acquisition efficiency.
Data Source
AI summary
A method, apparatus and computer program product are provided in order to allow an uplink resource request to be transmitted to the access point even in an instance in which the mobile terminal is receiving a continuous downlink transmission and repeated ACK/NACK transmissions are enabled. In this regard, a method, apparatus and computer program product are provided to prioritize a preamble transmission for a random access procedure relative to the repeated ACK/NACK transmissions. The method, apparatus and computer program also prioritize at least one message of the random access procedure.