METHODS AND APPARATUS FOR ASSET TRACKING
A method for enabling asset tracking that includes the steps of: receiving ( 910 ) a first excitation signal at a first power level using a first frequency band; and ( 920 ) upon determining that a first set of parameters is satisfied, awakening from an inactive mode to an active mode, transmitting data at a second power level that is greater than the first power level using a second frequency band that is different from the first frequency band, and returning to the inactive mode, wherein determining that the first set of parameters is satisfied comprises at least determining that the first excitation signal corresponds to a first wake-up circuit.
1 . A method for enabling asset tracking comprising the steps of:
receiving a first excitation signal at a first power level using a first frequency band; and
upon determining that a first set of parameters is satisfied,
awakening from an inactive mode to an active mode,
transmitting data at a second power level that is greater than the first power level using a second frequency band that is different from the first frequency band, and
returning to the inactive mode,
wherein determining that the first set of parameters is satisfied comprises at least determining that the first excitation signal corresponds to a first wake-up circuit.
2 . The method of claim 1 , wherein the first excitation signal corresponds to the first wake-up circuit when the first frequency band comprises a predetermined frequency band corresponding to the first wake-up circuit, and the first power level one of exceeds a predetermined threshold corresponding to the first wake-up circuit and is with a predetermined range corresponding to the first wake-up circuit.
3 . The method of claim 2 , wherein the second frequency band is lower than the first frequency band.
4 . The method of claim 3 , wherein the first frequency band in within at least one of an 800 MHz frequency band and a 900 MHz frequency band, and the second frequency band is within one of a 433 MHz frequency band.
5 . The method of claim 1 , wherein determining that the first set of parameters is satisfied further comprises determining that the first wake-up circuit has not been deactivated.
6 . The method of claim 5 , wherein if the first wake-up circuit has been deactivated, remaining in the inactive mode when the first excitation signal corresponds to the first wake-up circuit.
7 . The method of claim 1 , wherein the first wake-up circuit is one of a plurality of wake-up circuits.
8 . The method of claim 7 further comprising the step of receiving an instruction signal comprising an instruction to inactivate all but one of the plurality of wake-up circuits.
9 . The method of claim 8 further comprising the step of receiving a second excitation signal corresponding to a wake-up that has been deactivated and remaining in the inactive mode.
10 . The method of claim 1 , wherein the data is transmitted on a first channel selected from a plurality of channels.
11 . The method of claim 10 , wherein the first channel is selected using a random number process.
12 . Apparatus comprising:
an antenna
a receiver circuit coupled to the antenna and comprising at least one wake-up circuit, the receiver circuit,
receiving a first excitation signal at a first power level using a first frequency band; and
upon determining that a first set of parameters is satisfied, awakening from an inactive mode to an active mode, transmitting data at a second power level that is greater than the first power level using a second frequency band that is different from the first frequency band, and returning to the inactive mode, wherein determining that the first set of parameters is satisfied comprises at least determining that the first excitation signal corresponds to the at least one wake-up circuit; and
a transmitter circuit coupled to the antenna and to the receiver circuit to transmit the data.
13 . The apparatus of claim 12 , wherein the receiver circuit comprises a plurality of wake-up circuits to awaken the tag device, each wake-up circuit in the plurality being activated by a different excitation signal.
14 . The apparatus of claim 13 , wherein each wake-up circuit in the plurality is activated by a different corresponding frequency band used to receive its corresponding excitation signal, and each wake-up circuit comprises a Q-filter for controlling its corresponding frequency band.
15 . The apparatus of claim 14 , wherein the receiver comprises:
a first wake-up circuit comprising a first Q-filter coupled to a first envelop detection circuit for detecting an excitation signal received using an 800 MHz frequency band for activating the first wake-up circuit; and
at least a second wake-up circuit comprising a second Q-filter coupled to a second envelop detection circuit for detecting an excitation signal received using a 900 MHz frequency band for activating the second wake-up circuit.
16 . The apparatus of claim 12 further comprising a random number generator for selecting one of a plurality of channels for transmitting the data.
17 . A method for enabling asset tracking comprising the steps of:
receiving a first excitation signal at a first power level using a first frequency band; and
upon determining that a first set of parameters is satisfied,
awakening from an inactive mode to an active mode,
transmitting data at a second power level that is greater than the first power level using a second frequency band that is different from the first frequency band, and
returning to the inactive mode,
wherein determining that the first set of parameters is satisfied comprises at least determining that the first excitation signal corresponds to a first wake-up circuit of a plurality of wake-up circuits.