Detection of fast poll responses in a TWACS inbound receiver
First Claim
1. In a power line communication system for an electrical distribution network, a fast polling method for quickly and accurately polling electrical meters installed at user facilities to determine whether a meter is connected to the power line comprising:
- sending an outbound message over the network to a meter to ascertain whether or not an outage has occurred at the meter'"'"'s location;
the meter, if it receives the message, sending a fast poll response consisting of a known bit pattern back over the network;
processing the received signal using the known bits in the fast poll response to estimate a plurality of signal quality parameters;
combining values representing the signal quality parameters, using a weighted sum, to produce a single quality parameter; and
,comparing the quality parameter to an adaptively computed threshold to determine whether the response received from the meter was an actual response.
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Accused Products
Abstract
A method for use in a power line communication systems for an electrical distribution system (1) to quickly and accurately poll electrical meters (6) installed at user facilities to determine if an outage has occurred at a facility. An outbound communications message is transmitted to the meter at the facility requesting a short response consisting of a bit pattern that is either partially or completely known to the receiver. Any perceived response from the meter is then processed to ascertain whether or not the meter actually transmitted a message. Receipt of a message indicates that an outage has not occurred at that site, while an indication the message was not received indicates an outage has likely occurred. In processing the received message, two types of errors can potentially occur; i.e., a false positive or a false negative. A false positive occurs when a detection algorithm used to process the response indicates that the meter sent a response when actually it did not. A false negative occurs when the detection algorithm indicates the meter did not send a response when actually it did. The method utilizes a signal processing algorithm to determine if a response was actually sent by the meter and is important because it minimizes the probability of both types of errors.
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Citations
15 Claims
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1. In a power line communication system for an electrical distribution network, a fast polling method for quickly and accurately polling electrical meters installed at user facilities to determine whether a meter is connected to the power line comprising:
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sending an outbound message over the network to a meter to ascertain whether or not an outage has occurred at the meter'"'"'s location; the meter, if it receives the message, sending a fast poll response consisting of a known bit pattern back over the network; processing the received signal using the known bits in the fast poll response to estimate a plurality of signal quality parameters; combining values representing the signal quality parameters, using a weighted sum, to produce a single quality parameter; and
,comparing the quality parameter to an adaptively computed threshold to determine whether the response received from the meter was an actual response. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In a power line communications system for an electrical distribution network, a fast polling method for quickly and accurately polling electrical meters installed at user facilities to determine if an outage has occurred at a facility comprising:
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sending a message over the network to a meter to ascertain whether or not an outage has occurred at the meter'"'"'s location, the meter, if it receives the message, sending a fast poll response consisting of a known bit pattern; monitoring the network to detect the response and processing any perceived response to determine if the known bit pattern is present, presence of the known bit pattern indicative of the meter having received the fast poll message and that an outage has not occurred, while absence of the known bit pattern is indicative that the meter did not receive the fast poll message and an outage has occurred, processing of the perceived response including sampling of any bits comprising the response, generating a matrix comprising data obtained from the samples, and correlating the data in the matrix to produce an output vector upon which a determination is made with respect to the outage, the output vector incorporating factors relating to the signal power of the perceived response and its signal-to-noise ratio (SNR), the output vector x produced by the correlation being defined as; - View Dependent Claims (10, 11, 12, 13)
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14. In a power line communications system for an electrical distribution network, a fast polling method for quickly and accurately polling electrical meters installed at user facilities to determine if an outage has occurred at a facility comprising:
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sending a message over the network to a meter to ascertain whether or not an outage has occurred at the meter'"'"'s location, the meter, if it receives the message, sending a fast poll response consisting of a known bit pattern; monitoring the network to detect the response and processing any perceived response to determine if the known bit pattern is present, presence of the known bit pattern indicative of the meter having received the fast poll message and that an outage has not occurred, while absence of the known bit pattern is indicative that the meter did not receive the fast poll message and an outage has occurred, processing of the perceived response including sampling all of the bits comprising the response, generating a matrix S whose columns contain signal samples corresponding to each bit in the response, and computing signal parameters from the data in the matrix to produce an output vector xx upon which a determination is made with respect to the outage, the output vector incorporating factors relating to the quality of the received signal and being defined as;
xx=((STSkdk)/n)*nSdSkdkx,
where n is the number of reference bits, S is the matrix whose columns contain the signal samples corresponding to each bit in the response and ST is the matrix transposed, d is a column vector of a given dimension containing the transmitted data, and Sk and dk represent a known subset of the data represented by the bits, and the vector x represents the signal strength for each message bit; and
,at least one of signal quality metrics being a “
max-min”
metric used to determine the presence of absence of the signal and defined as; - View Dependent Claims (15)
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Specification