IAB AP-to-AP Link Deterioration Handling via CPE Relay
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Solution Overview
Problem
Integrated access and backhaul (IAB) networks face challenges in handling blockage and error propagation in AP-to-AP wireless links, which can lead to outages due to signal deterioration, especially in multi-hop configurations where blockages like trucks or birds can disrupt line-of-sight signals, causing errors to propagate across the network.
Innovation Solution
The method involves identifying signal deterioration in AP-to-AP wireless links and relaying data through a designated CPE (Customer Premises Equipment) on a direct wireless link, isolating the affected link from other APs and establishing alternative paths to prevent error propagation and reduce link failure probabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If narrow beams at millimeter wave bandwidths with strong line of sight (LOS) signal components are used to support high data rates, then data rate is improved, but the system performance is significantly affected if the LOS link is blocked
Solution Approach 1:
A CPE acts as an intermediary relay node between the source AP and destination AP when the direct LOS link is blocked. The CPE receives data from the source AP and forwards it to the destination AP, enabling data transmission without requiring a direct LOS path between APs. This resolves the contradiction by maintaining link reliability through alternative paths while preserving high data rates through the use of narrow beams and millimeter wave bandwidths on available paths.
2Reliability
If non-LOS paths with reflections are used to bypass blockage, then link continuity is improved, but the signals are by orders of magnitude weaker and retransmissions may be needed
Solution Approach 1:
The network path is segmented into multiple hops: source AP to CPE, and CPE to destination AP. Each segment uses direct LOS connections with narrow beams, avoiding the need for weak reflected non-LOS paths. This segmentation allows the system to maintain link continuity through relay nodes while preserving transmission efficiency by using high-gain narrow beams on each segment rather than relying on weak single-hop non-LOS signals.
3Device complexity
If a direct AP-to-AP wireless link is used for backhauling data, then the transmission path is simple, but error propagation occurs and outage will occur for all APs in successive hops if the link is blocked
Solution Approach 1:
The network topology is made dynamic by enabling CPEs to act as relay nodes when direct AP-to-AP links are blocked. Instead of a fixed simple path, the system can adaptively route data through alternative paths involving CPEs. This dynamic approach maintains network availability by providing fallback paths while keeping the normal operation simple through direct AP-to-AP links when available.
Data Source
AI summary
There is provided mechanisms for handling a deteriorating AP-to-AP wireless link in an IAB network. A method is performed by a first AP in the IAB network. The method comprises identifying signal deterioration of a first AP-to-AP wireless link between the first AP and a second AP in the IAB network. The first AP-to-AP wireless link is used for backhauling data for CPEs served by the second AP and for backhauling data for CPEs served by a third AP in the IAB network. The second AP has a second AP-to-AP wireless link to the third AP for backhauling data for the CPEs served by the third AP. The method comprises, in response thereto, relaying the data via a first CPE of the CPEs served by the second AP on a first direct wireless link between the first AP and the first CPE.