US 12,621,053 B2 · Synchronization in optical wireless networks for interference suppressing

Abstract

In an optical wireless communication, OWC, network (100), time division multiple access, TDMA, is commonly used for interference suppression among multiple network devices (D1-Dn) associated to a single coordinator, or among adjacent coordinators (C1-Cn). However, an offset of MAC cycles among two adjacent coordinators (C1-C2) may still result in interference to a network device (D1) located in the overlapping area of the coverage areas of these two adjacent coordinators (C1-Cn). This invention is directed to various methods, apparatus, systems, computer program and computer-readable media for providing a mechanism to make use of an out-of-band channel to send a signal from a network device (D1) to the two adjacent coordinators (C1-C2), for assisting the alignment of MAC cycles among the two adjacent coordinators (C1-C2), and the out-of-band channel has a line-of-sight character, and is out-of-band as compared to the OWC network (100).

Claims20

Dependent claims

A network device out of a plurality of network devices for reducing interference in an optical wireless communication (OWC) network having a line-of-sight character, the OWC network comprising at least two coordinators and the plurality of network devices selectively associated to and synchronized with a respective one of the coordinators, and wherein the at least two coordinators and the plurality of network devices share a same optical wireless medium of the OWC network covering a first pre-defined spectrum range via a time-division multiple access (TDMA) approach by dividing the wireless medium into consecutive time slots,

the network device comprising:
a first receiver configured to detect downlink communication over the OWC network within the first pre-defined spectrum range;
a controller configured to decide on assisting with alignment of Medium Access Control (MAC) cycles between at least two adjacent coordinators, based on the downlink communication from the at least two adjacent coordinators detected by the first receiver;
a second transmitter configured to send a signal comprising timing information related to MAC cycles of the at least two adjacent coordinators, via an out-of-band channel outside the first pre-defined spectrum range, upon the decision on assisting with the alignment of MAC cycles between the at least two adjacent coordinators for interference suppression;
wherein the timing information is one of a signal to indicate the start time of individual MAC cycles of the two adjacent coordinators, an offset among individual MAC cycles of the adjacent coordinators, and a start time of MAC cycles of one coordinator out of the adjacent coordinators;
and
wherein the out-of-band channel has a line-of-sight character.

4 more elements

A coordinator out of at least two coordinators for reducing interference in an optical wireless communication (OWC) network having a line-of-sight character, the OWC network comprising the at least two coordinators and a plurality of network devices selectively associated to and synchronized with a respective one of the coordinators, and wherein the at least two coordinators and the plurality of network devices share a same optical wireless medium of the OWC network covering a first pre-defined spectrum range via a time-division multiple access (TDMA) approach by dividing the wireless medium into consecutive time slots, the coordinator comprising:

a first transmitter configured to send out data via downlink communication over the OWC network within the first pre-defined spectrum range;
a second receiver configured to receive a signal from a network device via an out-of-band channel outside the first pre-defined spectrum range, and wherein the signal comprising timing information related to MAC cycles of at least two adjacent coordinators is intended to assist with alignment of MAC cycles between the at least two adjacent coordinators, from which the network device detects downlink communication;
wherein the out-of-band channel has a line-of-sight character.

A method for reducing interference at a coordinator out of at least two coordinators in an optical wireless communication (OWC) network having a line-of-sight character, the OWC network comprising the at least two coordinators and a plurality of network devices selectively associated to and synchronized with a respective one of the coordinators, and wherein the at least two coordinators and the plurality of network devices share a same optical wireless medium of the OWC network covering a first pre-defined spectrum range via a time-division multiple access (TDMA) approach by dividing the wireless medium into consecutive time slots, the method comprising the coordinator out of the at least two coordinators:

sending out data via downlink communication over the OWC network within the first pre-defined spectrum range;
and
receiving a signal from a network device comprising timing information related to MAC cycles of at least two adjacent coordinators via an out-of-band channel outside the first pre-defined spectrum range, and wherein the signal is intended to assist with alignment of MAC cycles between the at least two adjacent coordinators, from which the network device detects downlink communication;
wherein the out-of-band channel has a line-of-sight character.

1 more element

Dependencies are inferred from the claim text.

Synchronization in optical wireless networks for interference suppressing

Life of this patent

Synchronization in optical wireless networks for interference suppressing

Life of this patent

Abstract

Claims20