Collision mitigation in low-power, frequency-hopping, wide-area network
AssigneeSemtech Corporation
InventorsBaozhu NING, Olivier Bernard André Seller, Nicolas Sornin
Life of this patent
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Abstract
A hopping spread-spectrum wireless network for IoT applications operating in a predetermined frequency band, with mobile device that have unsynchronized local frequency references and receiving gateways that are capable of detecting whether modulated radio signals will collide in frequency in a collision time interval, and blanking the signals in the collision time. Preferably, the frequency band is subdivided into a sub-bands, and the mobile devices adapt the width of the sub-bands used for transmission based on a synchronization status indicative of the frequency error of the local frequency reference.
Claims18
A wireless communication network comprising a plurality of radio transmitting devices and at least one receiving gateway,
- the transmitting devices, being arranged to modulate a carrier and, processing the modulated signals into a spread spectrum radio signal by switching the frequency of the carrier among several hopping frequencies in the frequency band, according to a sequence, and transmitting the radio signal through a radio interface,
- the receiving gateway being arranged for receiving radio signals from said radio transmitting devices, for predicting whether detected modulated radio signals will collide in frequency in a collision time interval, and for blanking or weighting the signals in the collision time interval.
A radio transmitting device comprising a radio interface operating in a predetermined frequency band and a local frequency reference, wherein the frequency band comprises a plurality of contiguous or separated sub-bands, the device being operatively arranged for:
- obtaining a synchronization status indicative of the frequency error of the local frequency reference,
- adapting a width of the sub-bands in dependence of the synchronization status,
- modulating a carrier having a frequency in the transmission sub-band, to obtain modulated signals that, when measured using the local frequency reference of the transmitting node, are comprised in the adapted width of a sub-band,
- combining the modulated signals into a spread spectrum radio signal by switching the frequency of the carrier among several hopping frequencies in the frequency band, according to a sequence
- transmitting the radio signal through the radio interface.
Dependencies are inferred from the claim text.