Time-hopping low-power wireless network for turning off and on fluorescent lamps
First Claim
1. A time-hopping wireless network system comprising:
- a master unit; and
a remote lighting control unit, wherein the master unit is in wireless Radio Frequency (RF) communication with the remote lighting control unit, wherein the master unit transmits beacons in some but not all of a plurality of beacon slot times, wherein there is one beacon slot time in each of a corresponding one of a plurality of intervals, wherein the intervals of the plurality of intervals are all of identical duration, wherein the beacon slot times of a sequence of the plurality of intervals vary in time within their respective intervals from interval to interval in the sequence of intervals, and wherein the remote lighting control unit only transmits if commanded to by a beacon received from the master unit.
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Accused Products
Abstract
A low-power wireless network involves a master and a plurality of RF-enabled fluorescent lamp starter units. In each of a plurality of intervals, a starter wakes up and listens for a beacon, regardless of whether a beacon is transmitted during that interval or not. The starter operates in a low power sleep mode during the majority of the interval. The master can transmit during the beacon slot time of any interval, but typically only transmits frequently enough to maintain starter synchronization. If the master wishes to communicate with the starters with reduced latency, then the master can transmit a beacon in the next interval. Beacon slot time is varied within the interval (for example, from interval to interval or from group of intervals to group of intervals) in a pseudo-random time-hopping fashion known to both the starters and the master, thereby reducing persistence of collisions with similar networks.
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Citations
20 Claims
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1. A time-hopping wireless network system comprising:
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a master unit; and a remote lighting control unit, wherein the master unit is in wireless Radio Frequency (RF) communication with the remote lighting control unit, wherein the master unit transmits beacons in some but not all of a plurality of beacon slot times, wherein there is one beacon slot time in each of a corresponding one of a plurality of intervals, wherein the intervals of the plurality of intervals are all of identical duration, wherein the beacon slot times of a sequence of the plurality of intervals vary in time within their respective intervals from interval to interval in the sequence of intervals, and wherein the remote lighting control unit only transmits if commanded to by a beacon received from the master unit. - View Dependent Claims (2, 3)
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4. A method comprising:
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(a) in each of a plurality of intervals placing a receiver of a receiver unit into a receive mode, and then listening for a beacon during a predefined beacon slot time within the interval, and operating the receiver in a low-power sleep mode for substantially all the rest of the interval, wherein beacons are received by the receiver during the beacon slot times of some of the intervals but wherein no beacon is received during the beacon slot times of others of the intervals, wherein the beacon slot time of an interval has an offset time with respect to a time point within the interval, and wherein the offset time is varied in pseudo-random fashion from interval to interval; and (b) using the beacons received in (a) to synchronize the placing of the receiver into the receive mode with respect to the beacon slot times of the intervals. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system comprising:
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an occupancy detector that transmits a plurality of beacons, wherein each beacon is transmitted in a beacon slot time of a respective one of a plurality of intervals, wherein the beacon slot time of an interval has an offset time with respect to a time point within the interval, wherein the offset time is varied in pseudo-random fashion from interval to interval, and wherein the occupancy detector transmits no beacon in some beacon slot times of some of the intervals but does transmit beacons in beacon slot times of other ones of the intervals; and a fluorescent lamp starter unit that receives the beacons and uses the beacons to synchronize the placing of a receiver of the fluorescent lamp starter unit into a receive mode with respect to the beacon slot times of the intervals, wherein the receiver is placed into the receive mode during the beacon slot time of every one of the plurality of intervals. - View Dependent Claims (15)
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16. An apparatus comprising:
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a pair of terminals adapted to be coupled to a fluorescent lamp; and means for turning on the fluorescent lamp and for using a time-hopping Radio Frequency (RF) network protocol to receive a plurality of beacons, wherein each of a plurality of intervals has a beacon slot time, wherein the plurality of beacons is received by the means during the beacon slot times of some of the intervals but wherein no beacon is received during the beacon slot times of others of the intervals, wherein the means wakes up and operates in a higher power receive mode during a portion of each interval to listen for a beacon even if there is no beacon to receive during said each interval, wherein the means operates in a lower power sleep mode during a majority of each interval, and wherein the beacon slot times of at least some of the intervals vary in time-position within their respective intervals. - View Dependent Claims (17, 18, 19, 20)
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Specification