Multi-band channel capacity for meter network
A communication system that relays data messages from or to a plurality of remote endpoints via RF gateways to a data accumulation site over one of a series of communication channels. The communication system monitors the signal-to-noise ratio of communication from each individual endpoint, which can be utility meters and related control or monitoring points, to a gateway. Based upon a quality of service and/or the signal-to-noise ratio of the communication of the endpoints to the gateways, the system assigns a desired communication channel to the endpoint. Each of the desired communication channels have varying data transmission rate and required SNR and each channel is selected based upon the signal-to-noise ratio of the transmissions from the endpoint to the gateways. If the signal-to-noise ratio changes for an endpoint, the system dynamically reassigns a different channel to the meter based upon the updated signal-to-noise ratio.
1. A method of selecting a communication channel for each meter of a plurality of meters in a communication system including a plurality of gateways that each communicate to a back end server, the method comprising the steps of:
defining a plurality of communication channels in a continuous sequence between a first communication channel and a last communication channel, wherein the plurality of communication channels have increasing transmission rates and decreasing message durations from the first communication channel to the last communication channel;
initially assigning a default communication channel to each of the plurality of meters;
relaying a plurality of messages from each of the meters along the default communication channel;
determining the signal-to-noise ratio of the messages received at each of the gateways for each of the plurality of meters;
selecting one of the plurality of communication channels for each of the meters to optimize the modulation rate and message duration based upon the highest signal-to-noise ratio at one of the gateways for the plurality of message sent by the plurality of meters; and
assigning the selected communication channel to each of the plurality of meters, wherein the communication channels are assigned to the plurality of meters such that the plurality of meters are distributed across all of the plurality of communication channels such that at least one of the plurality of meters is assigned to each of the plurality of communication channels,
where tri-band operation is used such that the number of channels assigned is three where a first channel is assigned only endpoints having signal to noise ratio (SNR) to its best link margin gateway is low, and where a second channel is assigned only endpoints having a SNR to its best link margin gateway is medium, and where a third channel is assigned only endpoints having a SNR to its best link margin gateway is high.
2. The method of claim 1 where the first, second and third SNR channels are assigned endpoint traffic in a manor to normalize the total on-time or duty cycle of traffic such that the traffic is evenly spread.
3. The method of claim 1 where the first, second and third SNR channels are assigned endpoint traffic in a manor to normalize the total on-time or duty cycle of traffic such that the traffic is maximized into the high channel since more messages can be transacted per unit time.
4. The method of claim 1 wherein the default communication channel has a default modulation rate and a default message duration.
5. The method of claim 1 wherein at least one of the plurality of communication channels is defined as a priority channel, wherein each of the plurality of meters selectively communicates over the priority channel in addition to the communication channel assigned to the meter.
6. The method of claim 5 wherein the priority channel includes both an alarm sub-channel and a reply sub-channel.
7. The method of claim 6 wherein alarm messages are relayed to each of the plurality of meters over the alarm sub-channel and replies are communicated from each of the plurality of meters over the reply sub-channel.
8. The method of claim 1 wherein the plurality of meters are distributed into each of the plurality of communication channels such that meters having similar signal-to-noise ratios are assigned to the same communication channel.