Two-Stage Reordering in MAC and RLC for Multi-Node Wireless Reception
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Solution Overview
Problem
Existing wireless communication systems face challenges in processing and reconstructing packets received from multiple Node-Bs, leading to out-of-order reception and potential data dropping due to the lack of inter-site operation and reordering capabilities in MAC and RLC entities.
Innovation Solution
A two-stage reordering procedure is implemented in the WTRU, creating multiple MAC-ehs entities to ensure in-order delivery of packets from multiple Node-Bs, with additional MAC architecture configurations to manage and reorder packets before transmission to higher layers, utilizing sequence numbers and timers to handle out-of-order packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packets are received from multiple Node-Bs simultaneously, then data transmission rate is improved, but packet delivery order cannot be guaranteed and data dropping occurs
Solution Approach 1:
The patent divides the packet processing system into multiple MAC-ehs entities, with each entity dedicated to handling packets from a specific Node-B. This segmentation allows independent processing of packets from different sources while maintaining the ability to reorder them sequentially at the RLC layer, thus preserving delivery order despite simultaneous reception from multiple Node-Bs.
Solution Approach 2:
The patent introduces an intermediary reordering mechanism between the MAC-ehs entities and the RLC entity. This intermediary layer buffers incoming packets and reorders them based on sequence numbers before forwarding to RLC, acting as a mediator that ensures in-order delivery even when packets arrive out of order from multiple Node-Bs.
2Device complexity
If existing MAC architecture is used for inter-site operation, then device complexity is reduced, but out-of-order reception causes data dropping in MAC-ehs entities
Solution Approach 1:
The patent creates multiple MAC-ehs entities instead of using a single MAC entity for inter-site operation. Each MAC-ehs entity handles packets from a specific Node-B independently, which prevents the data dropping issues that occur in the existing single-MAC architecture when receiving out-of-order packets from multiple sites.
Solution Approach 2:
The patent performs preliminary reordering of packets at the MAC-ehs entity level before packets are passed to the RLC layer. By reordering packets early in the processing chain based on sequence numbers, the system prevents out-of-order packets from causing data dropping in subsequent processing stages.
3Adaptability or versatility
If packets are received from different sites, then network coverage and capacity are improved, but premature RLC status reporting occurs due to out-of-order reception
Solution Approach 1:
The patent introduces an intermediary reordering buffer between the MAC-ehs entities and the RLC entity. This buffer holds incoming packets temporarily and releases them in the correct sequence order, preventing premature RLC status reporting that would occur if out-of-order packets were forwarded directly to RLC.
Solution Approach 2:
The patent performs preliminary sequencing and reordering of packets at the MAC-ehs entity level before forwarding to RLC. By ensuring packets are in the correct order before RLC processing, the system prevents premature status reporting and allows RLC to operate efficiently with properly ordered input.
Data Source
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AI summary
A method for use in a wireless transmit receive unit (WTRU) for two-stage reordering of received protocol data units (PDUs). The method comprising receiving PDUs from a plurality of Node-Bs, wherein each of the received PDUs has a transmission sequence number (TSN), reordering the received PDUs from each of the plurality of Node-Bs using the TSN in a MAC layer in different reordering queues, delivering the received PDUs from a plurality of reordering queues to one logical channel in the RLC layer, reordering the received PDUs in the RLC layer based on a sequence number (SN), starting a timer when at least a RLC PDU is missing based on SN of the RLC PDU, and transmitting a status report indicating a missing RLC PDU based on SN of the RLC PDU on a condition that the timer expires, wherein transmission of the status report is delayed on a condition that a RLC PDU is missing based on SN of the RLC PDU and the timer is running.