Sequential Echo Canceller Training for Full Duplex Networks
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Solution Overview
Problem
Full duplex networks face challenges in efficiently training echo cancellers to cancel simultaneous upstream and downstream echoes in the same frequency spectrum, leading to costly N+0 architectures and reduced subscriber capacity.
Innovation Solution
The implementation of a method to train downstream and upstream echo cancellers sequentially, where the downstream echo canceller is trained first, followed by the upstream echo canceller, using network settings adjustments and idle grants to minimize interference and optimize echo cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amplifiers are inserted in between the node and the subscribers to increase subscriber capacity, then the network becomes more cost efficient and can service more subscribers, but echo is generated in both upstream and downstream directions making it hard to train echo cancellers
Solution Approach 1:
The patent applies preliminary action by training the downstream echo canceller first before training the upstream echo canceller. During the downstream echo canceller training phase, upstream transmissions are idle (not transmitting), which eliminates upstream echo interference and allows accurate training of the downstream echo canceller. After downstream echo cancellation is established, upstream transmissions are enabled and the upstream echo canceller is trained, with the downstream echo canceller already in place to handle downstream echo. This sequential training approach resolves the complexity of simultaneous two-directional echo cancellation training.
2Device complexity
If an N+0 architecture is used with no amplifiers between node and modems, then echo cancellation is simpler, but the number of subscribers that can be serviced is small and it is costly
Solution Approach 1:
The patent implements feedback by inserting amplifiers in the network path between the node and subscribers, which enables the network to service more subscribers (increasing productivity). The amplifiers boost signal strength to support additional subscribers while maintaining signal quality. Combined with the sequential echo canceller training approach, the feedback mechanism allows the system to achieve both high subscriber capacity and effective echo cancellation, making the N+1 or N+2 architecture more cost-efficient than N+0.
Data Source
AI summary
In some embodiments, a method receives a first signal that is sent in a first direction in a network. Communications in the network are full duplex communications in a same frequency band. The first signal is amplified in the first direction. The method trains a first echo canceller to cancel a first echo signal from the first signal where the first echo signal is received in a second direction. After training the first echo canceller, the trained first echo canceller is enabled. The method receives a second signal in the second direction that is sent in the second direction in the network. The second signal is amplified in the second direction. The method trains a second echo canceller to cancel a second echo signal received in the first direction from the second signal where the first echo canceller cancels the first echo signal that is received in the second direction.