US 10,764,855 B1Granted

Synchronizing clocks in a wireless network

AssigneeMarvell Asia Pte Ltd

InventorsLiwen Chu, Hongyuan Zhang, Hui-Ling Lou

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Abstract

A first communication device includes a first timer and a second communication device includes a second timer. The first communication device receives, from the second communication device, a packet that includes a timestamp that corresponds to a least significant portion of the second timer. The first communication device determines whether a most significant bit of a least significant portion of the first timer is different than a most significant bit of the timestamp. At least when the most significant bit of the least significant portion of the first timer is different than the most significant bit of the timestamp: the first communication device determines a mathematical difference between i) the least significant portion of the first timer and ii) the timestamp, and selectively adjusts a most significant portion of the first timer based on the mathematical difference. The first communication device uses the timestamp to set the least significant portion of the first timer.

Claims10

Dependent claims

A method of synchronizing a first timer at a first communication device with a second timer at a second communication device, wherein the first timer comprises a least significant portion and a most significant portion, and wherein the second timer comprises a least significant portion and a most significant portion, the method comprising:

receiving, at the first communication device, a packet that includes a timestamp, wherein the packet is from the second communication device, wherein the timestamp corresponds to the least significant portion of the second timer of the second communication device, and wherein the packet does not include any bits of the most significant portion of the second timer;
determining, at the first communication device, whether a most significant bit of the least significant portion of the first timer is different than a most significant bit of the timestamp;
at least when the most significant bit of the least significant portion of the first timer is different than the most significant bit of the timestamp, determining, at the first communication device, a mathematical difference between i) the least significant portion of the first timer and ii) the timestamp;
when the most significant bit of the least significant portion of the first timer is different than the most significant bit of the timestamp, selectively adjusting, at the first communication device, the most significant portion of the first timer based on the mathematical difference between i) the least significant portion of the first timer and ii) the timestamp;
and
using, at the first communication device, the timestamp to set the least significant portion of the first timer.

3 more elements

An apparatus for use in a communication network having a first communication device and a second communication device, wherein the first communication device includes a first timer and the second communication device includes a second timer, wherein the first timer comprises a least significant portion and a most significant portion, and wherein the second timer comprises a least significant portion and a most significant portion, the apparatus comprising:

a network interface device associated with the first communication device, wherein the network interface device includes i) one or more integrated circuits (ICs), and ii) a timer circuit implemented on the one or more ICs, wherein the timer circuit corresponds to the first timer;
wherein the one or more ICs are configured to:
receive a packet that includes a timestamp, wherein the packet is from the second communication device, wherein the timestamp corresponds to the least significant portion of the second timer of the second communication device, and wherein the packet does not include any bits of the most significant portion of the second timer;
determine whether a most significant bit of the least significant portion of the first timer is different than a most significant bit of the timestamp;
at least when the most significant bit of the least significant portion of the first timer is different than the most significant bit of the timestamp, determine a mathematical difference between i) the least significant portion of the first timer and ii) the timestamp;
when the most significant bit of the least significant portion of the first timer is different than the most significant bit of the timestamp, selectively adjust the most significant portion of the first timer based on the mathematical difference between i) the least significant portion of the first timer and ii) the timestamp;
and
use the timestamp to set the least significant portion of the first timer.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/262,616Filed 30 Jan 2019 · us provisional application
Priority: 26 Feb 2018
Granted: 1 Sep 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04W 56/0045
Compensating for timing error of reception due to propagation delay: compensating for timing error by altering transmission time
H04W 56/001
Synchronisation arrangements: synchronization between nodes
H04W 56/0065
Determining timing error of reception due to propagation delay: using measurement of signal travel time
H04W 84/12
Small scale networks; Flat hierarchical networks: wLAN [Wireless Local Area Networks]