Relay ARQ Process for Millimeter Wave Network Reliability
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Solution Overview
Problem
Millimeter wave (mmW) networks face challenges in providing reliable end-to-end transmission services due to the limitations of hop-by-hop RLC protocols, which fail to ensure packet delivery during handovers and intermediate node failures, especially in ultra-dense networks with wireless backhaul connections.
Innovation Solution
Implementing a Relay ARQ process that uses a local ARQ protocol at each hop, with a unified sequence number and flow ID for data packets, allowing temporary retransmissions at each node until end-to-end acknowledgment is received, and enabling dynamic addition of nodes to the Relay ARQ chain without explicit signaling, reducing latency and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hop-by-hop RLC protocols are used in mmW networks, then local packet transmission can be achieved, but reliable end-to-end packet delivery cannot be ensured during handovers and intermediate node failures
Solution Approach 1:
The patent implements nested ARQ protocols where a local ARQ process (inner loop) is embedded within an end-to-end ARQ process (outer loop). The local ARQ handles hop-by-hop retransmissions while the end-to-end ARQ ensures overall delivery reliability. This nested structure allows multiple levels of error correction without requiring a completely new protocol architecture.
Solution Approach 2:
The patent segments the ARQ functionality into separate local and end-to-end processes. Each process operates independently with its own sequence number space and acknowledgment mechanism. This segmentation allows the system to benefit from both local fast retransmission and global reliability without the complexity of a monolithic protocol.
2Reliability
If retransmissions are performed at each hop until end-to-end acknowledgment is received, then packet delivery reliability is improved, but latency increases
Solution Approach 1:
The patent implements preliminary retransmission actions at each local hop before waiting for end-to-end acknowledgment. Nodes perform local ARQ retransmissions proactively based on local feedback, reducing the need for repeated end-to-end retransmission cycles and thereby reducing overall latency.
Solution Approach 2:
The patent maintains continuous transmission flow by allowing parallel local and end-to-end ARQ processes. While end-to-end acknowledgment is pending, local retransmissions continue uninterrupted, ensuring continuous useful action rather than idle waiting, thus reducing effective latency.
3Ease of operation
If explicit signaling is used to add nodes to the Relay ARQ chain, then node management is simplified, but signaling overhead increases
Solution Approach 1:
The patent implements self-service node joining where new nodes automatically integrate into the Relay ARQ chain by listening to existing ARQ messages and adopting the established sequence number scheme. Nodes autonomously configure themselves without requiring explicit signaling from the network controller, eliminating signaling overhead for node addition.
Solution Approach 2:
The patent uses the existing ARQ message structure as an intermediary mechanism for node integration. Rather than introducing separate signaling messages, the ARQ protocol itself serves as the medium through which nodes learn about chain members and configure their ARQ parameters, reducing additional signaling overhead.
4Device complexity
If unified sequence number and flow ID are used for data packets, then routing without explicit path signaling is enabled, but packet tracking complexity increases
Solution Approach 1:
The patent makes the sequence number field universal by using it for multiple purposes: packet identification, routing decision, and ARQ acknowledgment matching. This multi-functionality eliminates the need for separate path signaling fields while maintaining packet tracking capability through the versatile sequence number mechanism.
Data Source
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AI summary
26 ABSTRACT There is disclosed a method for operating a network node (100) in a millimeter network, mmW network. The method comprises receiving a data packet comprising header information, the header information indicating a source ID, a destination ID, 5 a flow ID and a UE ID; and transmitting, to the preceding network node, an ARQ response message indicating the flow ID and the UE ID and ACK/NACK pertaining to the received data packet. The disclosure also pertains to related devices and methods.10 (Fig. 12)