# US 10,320,711 B2 · Real-time wireless multicast router

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- Number: US 10,320,711 B2
- Document ID: US10320711B2
- Status: Granted
- Kind: B2
- Application number: 15/114,804
- Filed: 2015-01-20
- Published: 2016-11-24
- Granted: 2019-06-11
- Earliest claimed: 2014-01-31
- Assignees: Signify Holding B.V.
- Applicants: Signify Holding B.V.
- Inventors: Theodorus Jacobus Johannes Denteneer; Petrus Desiderius Victor Van Der Stok
- Web page: https://patentgrep.com/patent/US10320711B2

## CPC

- H04L 49/201: Multicast operation; Broadcast operation
- H04L 45/20: {Hop count for routing purposes, e.g. TTL}
- H04L 47/286: {Time to live}
- H04L 47/32: by discarding or delaying data units, e.g. packets or frames
- H04L 47/564: {Attaching a deadline to packets, e.g. earliest due date first}
- H04L 65/65: Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
- H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
- H04L 2101/622: Layer-2 addresses, e.g. medium access control [MAC] addresses
- H04W 84/12: WLAN [Wireless Local Area Networks]
- Y02D 30/70: in wireless communication networks
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

This invention generally relates to Low-power and Lossy Wireless Networks. The proposed solution takes advantage of the fact that retry mechanism and back-off mechanism are already present in trickle-based algorithms. This way, it is possible to disable the equivalent features present at the MAC level which are the main causes of the large maxima of the fluctuating end-to-end delay. Also, it has been done away with the additional waiting time which comes from the packet waiting in the buffer in the MAC. Therefore, it has been provided a real-time layer with a limited size buffer able to allocate a deadline to a multicast packet and to select packets for transmission or rejection on the basis of the packet deadline. This way, it is kept a tighter hold on the rejection and waiting of the packets.

## Claims

### Claim 1

A router for controlling multicast transmission in a low-power wireless network, the router comprising:
a trickle-based multicast protocol layer, MPL, interface adapted to create a multicast packet; and,
a Medium Access Control, MAC, layer interface comprising a MAC layer queue adapted to receive a plurality of multicast packets, the MAC layer interface being adapted to transmit, over the network, the multicast packets stored in the MAC layer queue in their order of arrival, the MAC layer interface further comprising a MAC retry mechanism associated with a backoff mechanism and adapted to retransmit unsuccessfully transmitted multicast packets;
a real-time layer, RTL, interface coupled to the MPL layer interface and the MAC layer interface, wherein the RTL interface disables the MAC layer queue, the MAC retry mechanism and the MAC backoff mechanism and receives the multicast packet from the MPL layer interface,
alters the multicast packet by adding a deadline by which said altered ,multicast packet is to be discarded by a router of the network, and, discards said multicast packet where said deadline has already passed;
wherein the RTL interface further forwards said altered multicast packet to the MAC layer interface when the latter is ready to transmit puts said altered multicast packet on hold when the MAC layer is not ready to transmit, and forwards or puts on hold said altered multicast packet based on said deadline.

### Claim 2 (depends on 1)

The router of claim 1, wherein when the MAC layer interface is not ready to transmit and that at least two altered multicast packets are put on hold, the RTL interface is further adapted to discard at least the multicast packet having the shortest deadline.

### Claim 3 (depends on 1)

The router of claim 1, wherein when the MAC layer interface has unsuccessfully transmitted a first altered multicast packet and that at least a second altered multicast packet originating from the MPL interface is put on hold, the RTL interface is further adapted to receive and put on hold the first altered multicast packet received from the MAC layer interface and to discard at least the multicast packet having the shortest deadline.

### Claim 4 (depends on 1)

The router of claim 1, wherein the deadline is based on the time of generation of the multicast packet at its source router on the network.

### Claim 5 (depends on 1)

The router of claim 1, wherein the deadline is based on an actual clock time of the router and a number of hops travelled by the altered multicast packet from its source router to the router.

### Claim 6 (depends on 1)

The router of claim 1, wherein the low-power wireless network is a wireless lighting network.

### Claim 7 (depends on 1)

The router of claim 1, wherein the MPL layer interface is the Multicast Protocol for Low power and Lossy Networks.

### Claim 8 (depends on 1)

The router of claim 1, wherein the MAC layer interface is one the IEEE 802.15.4, Bluetooth or Low Power Wi-Fi.

### Claim 9

Method of controlling multicast transmission in a low-power wireless network, the method comprising:
providing a trickle-based multicast protocol layer, MPL, interface adapted to create a multicast packet; and,
providing a Medium Access Control, MAC, layer interface comprising a MAC layer queue adapted to receive a plurality of multicast packets, the MAC layer interface being adapted to transmit, over the network, the multicast packets stored in the MAC layer queue in their order of arrival, the MAC layer interface further comprising a MAC retry mechanism associated with a backoff mechanism and adapted to retransmit unsuccessfully transmitted multicast packets;
providing a real-time layer, RTL, interface coupled to the MPL layer interface and the MAC layer interface, wherein the RTL interface disables the MAC layer queue, the MAC retry mechanism and the MAC backoff mechanism; and receives the multicast packet from the MPL layer interface; and alters the multicast packet by adding a deadline by which said altered multicast packet is to be discarded by a router of the network; and discards said multicast packet where said deadline has already passed; and forwards said altered multicast packet to the MAC layer interface when the latter is ready to transmit; and puts said altered multicast packet on hold when the MAC layer is not ready to transmit; and forwards or puts on hold said altered multicast packet based on the deadline.

### Claim 10 (depends on 9)

The method of claim 9, wherein when the MAC layer interface is not ready to transmit and that at least two altered multicast packets are put on hold, the method further comprises discarding at least the multicast packet having the shortest deadline.

### Claim 11 (depends on 9)

The method of claim 9, wherein when the MAC layer interface has unsuccessfully transmitted a first altered multicast packet and that at least a second altered multicast packet originating from the MPL interface is put on hold, the method further comprises receiving and putting on hold the first altered multicast packet received from the MAC layer interface and discarding at least the multicast packet having the shortest deadline.

### Claim 12 (depends on 9)

The method of claim 9, wherein the deadline is based on the time of generation of the multicast packet at its source router on the network.

### Claim 13 (depends on 9)

The method of claim 9, wherein the deadline is based on an actual clock time of the router and a number of hops travelled by the altered multicast packet from its source router to the router.

### Claim 14 (depends on 9)

The method of claim 9, wherein the MPL layer interface is the Multicast Protocol for Low power and Lossy Networks layer interface and the MAC layer interface is one the IEEE 802.15.4, Bluetooth or Low Power Wi-Fi.

### Claim 15 (depends on 9)

A non-transitory computer readable medium having stored thereon instructions for causing one or more processing units to execute the method according to claim 9.