RLC Status PDU Construction for Radio Resource Constraints
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Solution Overview
Problem
In the LTE mobile communication system, when the size of available radio resources is smaller than the STATUS PDU, the RLC protocol encounters a deadlock situation as the MAC layer does not allocate sufficient radio resources for the RLC STATUS PDU transmission.
Innovation Solution
The method involves constructing a partial STATUS PDU, where the ACK_SN is set to a random value within the range of VR(R) to VR(MS), allowing the transmission of NACK_SN elements up to the limit of available radio resources, enabling the transmission of status information even when resources are insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the RLC protocol sends a complete STATUS PDU containing all NACK_SN elements, then the transmitting side can accurately identify all unsuccessfully received PDUs, but the STATUS PDU size exceeds the available radio resources causing transmission failure
Solution Approach 1:
The patent applies partial action by transmitting only a subset of NACK_SN elements that fit within the available radio resources rather than all NACK_SN elements. The receiving side determines how many NACK_SN elements can be included based on the allocated resource size, and the transmitting side processes only those included elements, achieving partial status reporting that prevents deadlock while working within resource constraints.
2Productivity
If the MAC layer allocates radio resources based on buffer status, then efficient resource utilization is achieved, but insufficient resources are allocated when the buffer contains more status information than can be transmitted
Solution Approach 1:
The patent implements dynamics by making the STATUS PDU content adaptive to the allocated radio resource size. The receiving side dynamically adjusts the number of NACK_SN elements included in the STATUS PDU based on the resource allocation received from the MAC layer. This dynamic adjustment allows the protocol to operate reliably under varying resource conditions without causing deadlock, while the MAC layer maintains efficient resource allocation based on actual buffer status.
Data Source
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AI summary
A method for transmitting a status protocol data unit, PDU, in a mobile communications system is proposed, which comprises: constructing a status PDU providing positive and/or negative acknowledgements of acknowledged mode data, AMD, PDUs or portions of AMD PDUs by considering available resources, such that the constructed status PDU fits to a total size of the available resources; and transmitting the constructed status PDU to a peer radio link control, RLC, entity.