PSE Powered Device Detection via Pseudo-Random Pulse Sequences
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Solution Overview
Problem
There is a need for a mechanism to detect powered devices over a network that prevents Power Sourcing Equipment (PSE) from sourcing power to non-powered devices and avoids being fooled by other PSEs, ensuring interoperability and secure power distribution in communication networks.
Innovation Solution
A method and apparatus that generate and transmit a unique, infinite pseudo-random sequence of pulses with pseudo-random inter-pulse delays and polarities to determine if a link partner is a powered device, using a pulse generator and detector to listen for expected behavior and declare the presence of a powered device if a sufficient number of matches are observed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a PSE uses a simple detection method to identify powered devices, then the device complexity is reduced, but the reliability of detection decreases leading to false identification of powered devices
Solution Approach 1:
The patent employs dynamic detection sequences with varying pulse patterns, delays, and polarities rather than static detection signals. The PSE transmits a series of detection pulses with randomized characteristics that change over time, making the detection process adaptive and dynamic. This resolves the contradiction by implementing a relatively complex but dynamically adjustable detection mechanism that maintains reliability while avoiding unnecessary static complexity.
Solution Approach 2:
The detection mechanism incorporates feedback loops where the PSE monitors the response to transmitted detection pulses and adjusts subsequent detection parameters based on observed behavior. The system uses match counters and threshold comparisons to evaluate responses, creating a feedback-driven detection process that improves reliability through iterative validation rather than relying on simple single-shot detection.
2Measurement precision
If a PSE transmits frequent detection pulses to accurately identify powered devices, then the measurement precision improves, but the use of energy increases
Solution Approach 1:
The patent implements periodic detection pulse transmission with configurable intervals rather than continuous transmission. The PSE sends detection pulses at specific periodic intervals, allowing the system to achieve adequate measurement precision through repeated sampling while consuming energy only during pulse transmission events. This periodic approach balances detection precision requirements with energy conservation.
Solution Approach 2:
The detection mechanism uses a series of detection pulses with a predetermined number of trials rather than exhaustive continuous detection. By transmitting a sufficient but limited number of detection pulses and using threshold-based decision making, the system achieves adequate detection precision without the excessive energy consumption that would result from continuous or overly frequent detection attempts.
3Reliability
If the PSE uses a long detection sequence to reduce false detection, then the reliability improves, but the loss of time increases
Solution Approach 1:
The patent implements preliminary detection steps using quick-response indicators before initiating full detection sequences. The system first checks for basic presence indicators and only proceeds to longer, more accurate detection sequences when initially suspected. This preliminary filtering reduces the average detection time while maintaining high reliability by applying comprehensive detection only when necessary.
Solution Approach 2:
The detection sequence length and complexity are dynamically adjusted based on initial observations and intermediate results. The system can terminate detection early when conclusive evidence is found or when thresholds are clearly met, rather than always executing fixed-length sequences. This dynamic adaptation reduces average detection time while preserving detection reliability through conditional early termination.
Data Source
AI summary
A novel mechanism for detecting the presence of powered devices over a network. A unique, infinite pseudo-random sequence of pulses are generated and transmitted over the network to the link partner attached to the other end of the cable. At each time unit, the PSE decides whether or not to transmit a pulse at that time. Thus, the pulses generated have pseudo-random inter-pulse delays between them. In addition, each pulse is pseudo-randomly selected to have either positive or negative polarity. If the link partner is a powered device it will be in loopback mode and the transmitted pulses will be looped back to the transmitter (i.e. the PSE). The PSE, at each time unit regardless of whether or not a pulse was transmitted, opens a search window in which it listens to the RX line for the appropriate expected behavior. If a pulse was transmitted, the PSE expects to see a pulse looped back. Similarly, if no pulse was transmitted, the PSE does not expect to receive a signal during the search window. If the expected behavior is observed, a match counter is incremented, otherwise a mismatch counter is incremented. If a sufficient number of matches are received, the PSE concludes that a powered device is present on the network.