RLC Entity State Variable Initialization for D2D Communication
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Solution Overview
Problem
Current D2D communication systems face challenges in efficiently processing received RLC PDUs, particularly in setting appropriate state variables for RLC entities to manage sequence numbers and reordering of data units, which affects data transmission reliability and efficiency.
Innovation Solution
A method and device for processing received RLC PDUs in a D2D communication system by setting state variables such as VR(UH) and VR(UR) to initial values based on the sequence number of the first received RLC PDU, allowing for efficient reordering and delivery of data units, including the use of timers and offset values for managing reordering buffers and PDCP entity synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If state variables VR(UH) and VR(UR) are initialized to zero in conventional RLC entities, then the RLC entity can process RLC PDUs with sequence numbers starting from zero, but it cannot efficiently handle D2D communication where the first received PDU may have a non-zero sequence number, leading to incorrect PDU processing and delivery
Solution Approach 1:
The patent changes the initialization parameters of state variables VR(UH) and VR(UR) from fixed zero values to dynamic values based on the actual first received PDU's sequence number. Specifically, VR(UH) is initialized to the sequence number of the first received PDU, and VR(UR) is initialized to VR(UH) minus the window size. This parameter change enables the RLC entity to correctly process PDUs in D2D communication where sequence numbers may not start from zero, while maintaining the standard RLC operation for conventional communications.
2Ease of manufacture
If the RLC entity uses fixed window size and state variable initialization, then the processing logic is simple and standardized, but it fails to accommodate D2D communication scenarios where the first received PDU may have arbitrary sequence numbers, causing incorrect reordering and delivery
Solution Approach 1:
The patent applies preliminary action by initializing the state variables VR(UH) and VR(UR) based on the sequence number of the first received PDU before normal RLC processing begins. This preliminary initialization ensures that the RLC entity is properly configured to handle the specific D2D communication scenario from the start, preventing errors in PDU reordering and delivery that would occur with fixed zero initialization.
Solution Approach 2:
The invention changes the initialization parameters from fixed values to dynamic values derived from the actual communication context. By setting VR(UH) to the first received PDU's sequence number and VR(UR) to VR(UH) minus window size, the system maintains implementation simplicity while achieving reliable D2D communication processing.
3Ease of operation
If conventional RLC state variable initialization is used in D2D communication, then the implementation follows existing standards and is straightforward, but the sequence number management becomes incorrect when the first PDU has a non-zero sequence number, leading to data loss or incorrect delivery
Solution Approach 1:
The patent modifies the initialization parameters of VR(UH) and VR(UR) to preserve sequence number information accuracy in D2D communication. By initializing VR(UH) to the first received PDU's sequence number rather than zero, the system maintains correct sequence number management throughout the communication process, preventing information loss while keeping the implementation straightforward.
Data Source
AI summary
The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for processing received RLC PDUs for D2D communication system, the method comprising: receiving a first RLC (Radio Link Control) PDU (Protocol Data Unit) for a RLC entity from a peer UE; setting a plurality of state variables for the RLC entity to initial values, respectively, wherein the plurality of state variables for the RLC entity comprises VR(UH) and VR(UR), and the an initial value of VR(UH) is a RLC sequence number (SN) of the first RLC PDU, and an initial value of VR(UR) is ‘the RLC SN of the first RLC PDU-offset’; and processing the first RLC PDU using the initial values.