Variable downlink-uplink boundary
First Claim
1. A method of operating an end node to communicate with a central node, the method comprising:
- wirelessly receiving, a beacon signal periodically-transmitted from the central node;
each beacon signal denoting the start of a single frame;
each frame being organized to include a downlink (DL) phase which precedes an uplink (UL) phase; and
a payload of the beacon signal including an offset which represents a starting time of the UL phase;
generating a message;
selecting, unbeknownst to the central node, at least one UL logical-channel, respectively; and
wirelessly transmitting, during the UL phase, at least a portion of the message from the end node over the selected at least one UL logical-channel according to a slotted ALOHA technique,wherein the wirelessly transmitting includes;
packetizing the message according to a slot size common to a predefined first group of M orthogonal spreading factors, respectively, thereby yielding one or more packets, with M being a non-zero, positive integer; and
awaiting, based on the offset, a start of the UL phase; and
sending, during the UL phrase, at least one of the one or more packets as the at least a portion of the message.
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Accused Products
Abstract
A method of operating an end node to communicate with a central node, the method comprising: wirelessly receiving, a beacon signal periodically-transmitted from the central node; each beacon signal denoting the start of a single frame; each frame being organized to include a downlink (DL) phase which precedes an uplink (UL) phase; and a payload of the beacon signal including an offset which represents a starting time of the UL phase. The method further comprises: generating a message; selecting, unbeknownst to the central node, at least one UL logical-channel, respectively; and wirelessly transmitting, during the UL phase, at least a portion of the message from the end node over the selected at least one UL logical-channel according to a slotted ALOHA technique.
21 Citations
26 Claims
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1. A method of operating an end node to communicate with a central node, the method comprising:
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wirelessly receiving, a beacon signal periodically-transmitted from the central node; each beacon signal denoting the start of a single frame; each frame being organized to include a downlink (DL) phase which precedes an uplink (UL) phase; and a payload of the beacon signal including an offset which represents a starting time of the UL phase; generating a message; selecting, unbeknownst to the central node, at least one UL logical-channel, respectively; and wirelessly transmitting, during the UL phase, at least a portion of the message from the end node over the selected at least one UL logical-channel according to a slotted ALOHA technique, wherein the wirelessly transmitting includes; packetizing the message according to a slot size common to a predefined first group of M orthogonal spreading factors, respectively, thereby yielding one or more packets, with M being a non-zero, positive integer; and awaiting, based on the offset, a start of the UL phase; and sending, during the UL phrase, at least one of the one or more packets as the at least a portion of the message. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An end node configured to communicate with a central node, the end node comprising:
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a wireless transceiver configured to receive and transmit messages, respectively; a memory; and one or more processors operatively connected with the wireless transceiver, and configured to execute contents of the memory comprising a wireless interface configured to receive, via the wireless transceiver, a beacon signal periodically-transmitted from the central node; each beacon signal denoting the start of a single frame; each frame being organized to include a downlink (DL) phase which precedes an uplink (UL) phase; and a payload of the beacon signal including an offset which represents a starting time of the UL phase; a message generator configured to generate a message; a logical-channel (LC) selector configured to select, unbeknownst to the central node, at least one UL logical-channel, respectively; a timer configured to elapse a delay time based on the offset and thereby then indicate a start of the UL phase; and a packetizer configured to packetize the message according to a slot size common to a predefined first group of M spreading factors, respectively, thereby yielding one or more packets, with M being a non-zero, positive integer; wherein the wireless interface is further configured to await, based on the offset, the start of the UL phase; and transmit, during the UL phase, at least a portion of the message over the selected at least one UL logical-channel according to a slotted ALOHA technique; in which at least one of the one or more packets is transmitted as the at least a portion of the message. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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11. The end node of claim 8, wherein the wireless interface is further configured to:
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wirelessly receive, via the wireless transceiver, in half-duplex; and wirelessly transmit, via the wireless transceiver, in half-duplex.
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12. The end node of claim 8, wherein:
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the wireless interface, via the wireless transceiver, is further configured to wirelessly receive the beacon signal on a DL logical-channel corresponding to a predefined physical channel and a predefined spreading factor selected from a second group of N orthogonal spreading factors; and the physical channel has a sufficiently wide bandwidth such that the beacon signal is exempted from a frequency-hopping requirement.
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13. The end node of claim 8, wherein:
the wireless interface, via the wireless transceiver, is further configured to use an unlicensed spectrum.
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14. The end node of claim 8, wherein:
the wireless interface, via the wireless transceiver, is further configured to wirelessly receive and to wirelessly transmit according to a low-power, low-bandwidth modulation format.
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15. A method of operating a central node to wirelessly communicate with an end node, the method comprising:
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generating periodically a beacon signal; each beacon signal denoting the start of a single frame; and each frame being organized to include a downlink (DL) phase which precedes an uplink (UL) phase; adaptively determining a duration of the DL phase and a start of the UL phase; configuring the beacon signal with a payload which includes; an offset indicating when the UL phase will begin; wirelessly transmitting periodically the beacon signal; awaiting a start of the UL phase based on the offset; and wirelessly listening, beginning at the UL phase-start, as follows; on each of M*N UL logical-channels resulting from a predefined first group of M physical-channels, respectively, and a predefined second group of N orthogonal spreading factors usable on each physical-channel, respectively; and for one or more messages transmitted from the end node, respectively, according to a slotted ALOHA technique; wherein M and N are non-zero, positive integers, respectively. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A central node configured to wirelessly communicate with an end node, the central node comprising:
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a wireless transceiver configured to at least receive and transmit messages, respectively; a memory; and one or more processors operatively connected with the wireless transceiver, and configured to execute contents of the memory comprising a beacon-signal generator configured to generate periodically a non-hopping beacon signal; each beacon signal denoting the start of a single frame; and each frame being organized to include a downlink (DL) phase which precedes an uplink (UL) phase; a time-boundary determiner configured to adaptively determine a duration of the DL phase and a start of the UL phase; the beacon-signal generator being further configured to include, in a payload of the beacon signal, an offset indicating when the UL phase will begin; a wireless interface configured to transmit periodically, via the wireless transceiver, the beacon signal; and a timer configured to elapse a delay time based on the offset and thereby then indicate a start of the UL phase; the wireless interface being further configured to listen, via the wireless transceiver and beginning at the UL phase-start, as follows; on each of M*N UL logical-channels resulting from a predefined first group of M physical-channels, respectively, and a predefined second group of N orthogonal spreading factors usable on each physical-channel, respectively; and for one or more messages transmitted from the end node, respectively, according to a slotted ALOHA technique; wherein M and N are non-zero, positive integers, respectively. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification