US 12,641,032 B1Granted

System for latency normalization

AssigneeAmazon Technologies, Inc.

InventorsDaniel Todd Cohn, Mitchell Bernard Skiba, Timothy Dennis Crain, Dandan Wang

Life of this patent

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Abstract

Variations in latency, out-of-order, and duplication may occur for incoming packets delivered via a network including a constellation of low-Earth orbit (LEO) satellites. An incoming packet that comprises time data and a sequence number is received at a user terminal. A delivery deadline time (deadline) is determined for the incoming packet. The incoming packet and its deadline are stored in a waiting buffer. Packets from the waiting buffer are processed for storage into “slots” that correspond to sequence numbers of the incoming packets. A window designates which portion of the slots may be written to or read from. The window may comprise a circular buffer. The window may be “moved” relative to the slots based on sequence number of an incoming packet, highest packet transmitted, maximum permitted movement, lowest window stop, highest window stop, and so forth. Packets in slots within the window that have reached their deadline are sent.

Claims20

Dependent claims

A user terminal (UT) device comprising:

a satellite network interface;
and
a first set of one or more processors executing instructions to:
determine parameters comprising:
a delivery margin indicative of a maximum expected latency of transfer of a packet from a first device to the UT device, and
a window size indicative of a number of sequential slots included in a window;
receive a first incoming packet using the satellite network interface;
determine, based on a first header of the first incoming packet, a first sequence number;
determine, based on the first sequence number, a first sequence number series associated with the first incoming packet;
determine, based on the first header of the first incoming packet, a first transmission time;
determine, based on the first transmission time and the delivery margin, a first deadline that is associated with the first incoming packet;
determine a first set of slots, wherein each slot is associated with a respective sequence number of the first sequence number series and includes the first sequence number;
determine the window with respect to the first set of slots, wherein the window has the window size;
store the first incoming packet in a first buffer, wherein the first incoming packet is associated the first sequence number and the first deadline;
determine the first sequence number is within the window;
and
store the first incoming packet at a slot within the window that is associated with the first sequence number.

14 more elements

A computer-implemented method comprising:

determining parameters comprising:
a delivery margin indicative of a maximum expected latency of transfer of a packet from a first device to a user terminal (UT) device, and
a window size indicative of a number of sequential slots included in a window;
receiving a first incoming packet;
determining, based on a first header of the first incoming packet, a first sequence number;
determining, based on the first sequence number, a first sequence number series associated with the first incoming packet;
determining, based on the first header of the first incoming packet, a first transmission time;
determining, based on the first transmission time and the delivery margin, a first deadline that is associated with the first incoming packet;
determining a first set of slots, wherein each slot is associated with a respective sequence number of the first sequence number series and includes the first sequence number;
determining the window with respect to the first set of slots, wherein the window has the window size;
storing the first incoming packet in a first buffer, wherein the first incoming packet is associated the first sequence number and the first deadline;
determining the first sequence number is within the window;
and
storing the first incoming packet at a slot within the window that is associated with the first sequence number.

11 more elements

A system comprising:

a first set of one or more processors executing instructions to:
receive a first incoming packet;
determine, based on a first header of the first incoming packet, a first sequence number;
determine, based on the first sequence number, a first sequence number series associated with the first incoming packet;
determine a delivery margin indicative of a latency to transfer a packet;
determine, based on the first header of the first incoming packet, a first transmission time;
determine, based on the first transmission time and the delivery margin, a first deadline that is associated with the first incoming packet;
determine a first set of slots, wherein each slot is associated with a respective sequence number of the first sequence number series and includes the first sequence number;
determine a window with respect to the first set of slots, wherein the window has a window size;
store the first incoming packet in a first buffer, wherein the first incoming packet is associated the first sequence number and the first deadline;
determine the first sequence number is within the window;
and
store the first incoming packet at a slot within the window that is associated with the first sequence number.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/900,195Filed 27 Sep 2024 · us provisional application
Priority: 29 Sep 2023
Granted: 26 May 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04L 47/34
Flow control; Congestion control: ensuring sequence integrity, e.g. using sequence numbers
H04L 47/27
Flow control; Congestion control: evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
H04L 49/90
Packet switching elements: buffering arrangements
H04L 67/12
Protocols: specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in…