IP Library › Granted Patent US 9,426,762
Granted Patent B2
US 9,426,762 · App. 14/160,449 · Granted Aug 23, 2016

Timing synchronization for networks with radio links

Inventors: Kristian Ehlers (Skovlunde, DK); Brian Branscomb (Hopkinton, MA); Thomas Kirkegaard Joergensen (Soeborg, DK)
Assignee: Microsemi Communications, Inc.
H04W56/001H04J3/0664H04J3/0673H04L12/4625H04J3/0682H04J3/0697H04W56/005H04W56/0075
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Quick Facts
Patent No.
US 9,426,762
App. No.
14/160,449
Granted
Aug 23, 2016
Kind
B2
Abstract

Precision Timing Protocol (PTP) related functions for use in packet communications carried in part by a microwave communications link include setting of time of day values across the microwave link and providing transparent clock functions. The PTP functions may be used for synchronizing radio base stations in a cellular network. The transparent clock can bridge Ethernet switches associated with microwave stations providing the microwave communications link.

Claims (48)

1. A method of performing timing related processing in a packet-based network communications over a communications link, the method comprising:

synchronizing a clock of a first Ethernet switch with a clock of a second Ethernet switch separated by a microwave communications link, the first Ethernet switch being part of a first microwave station and the second Ethernet switch being part of a second microwave station;

determining a time of arrival of a packet at the first Ethernet switch using a first time of day (TOD) domain, said first TOD domain associated with the first Ethernet switch;

determining a time of departure of the packet from the first Ethernet switch utilizing the first TOD domain;

determining a time of departure of the packet from the first microwave station utilizing a second TOD domain, said second TOD domain associated with circuitry performing communication link functions of the microwave communications link;

transmitting the packet, including information regarding the determined time of departure of the packet from the first microwave station utilizing the second TOD domain, from the first microwave station to the second microwave station;

determining a time of arrival of the packet at the second microwave station utilizing the second TOD domain;

determining a time of arrival of the packet at the second Ethernet switch utilizing the first TOD domain;

determining a time of departure of the packet from the second Ethernet switch utilizing the first TOD domain; and

setting a correction field of the packet to a value based on at least the determined time of departure of the packet from the first microwave station utilizing the second TOD domain, the determined time of arrival of the packet at the first Ethernet switch utilizing the first TOD domain and one at least one of:

the determined time of departure of the packet from the first Ethernet switch utilizing the first TOD domain;

the determined time of arrival of the packet at the second microwave station utilizing the second TOD domain;

the determined time of arrival of the packet at the second Ethernet switch utilizing the first TOD domain; and

the determined time of departure of the packet from the second Ethernet switch utilizing the first TOD domain.

2. The method of claim 1 , wherein the first TOD domain and the second TOD domain are independent of one another.

3. The method of claim 1 , wherein said synchronizing comprises:

determining, by a one of the first Ethernet switch and the second Ethernet switch, an expected time of day value for a time in the future at which a periodic signal is to be commonly received or generated by the first Ethernet switch and the second Ethernet switch; and

transmitting the expected time of day value over the microwave communications link to the other of the first Ethernet switch and the second Ethernet switch.

4. The method of claim 1 , wherein setting the correction field of the packet is based on all of:

the determined time of departure of the packet from the first Ethernet switch utilizing the first TOD domain;

the determined time of arrival of the packet at the second microwave station utilizing the second TOD domain;

the determined time of arrival of the packet at the second Ethernet switch utilizing the first TOD domain; and

the determined time of departure of the packet from the second Ethernet switch utilizing the first TOD domain.

5. The method of claim 1 , wherein said synchronizing is performed by way of transmission and reception of precision time protocol messages transmitted and received by way of a microwave side channel of the microwave communications link.

6. A communication system comprising:

a first microwave station comprising a first packet handling circuitry; and

a second microwave station comprising a second packet handling circuitry, the second packet handling circuitry separated from the first packet handling circuitry by a microwave communications link between the first and second microwave stations, a clock of the first packet handling circuitry synchronized with a clock of the second packet handling circuitry,

the first packet handling circuitry configured to determine a time of arrival of a packet at the first packet handling circuitry utilizing a first time of day (TOD) domain, and further configured to determine a time of departure of the packet from the first packet handling circuitry utilizing the first TOD domain, said first TOD domain associated with the first packet handling circuitry,

a circuitry performing communication link functions of the microwave communications link of said first microwave station configured to determine a time of departure of the packet from the first microwave station utilizing a second TOD, said second TOD domain associated with the circuitry performing communication link functions of the microwave communications link,

the circuitry performing communication link functions of the microwave communications link further configured to transmit the packet, including information regarding the determined time of departure of the packet from the first microwave station utilizing the second TOD domain, from the first microwave station to the second microwave station, the circuitry performing communication link functions of the microwave communications link of the second microwave station configured to determine a time of arrival of the packet at the second microwave station utilizing the second TOD domain,

the second packet handling circuitry configured to determine a time of arrival of the packet at the second packet handling circuitry utilizing the first TOD domain and further configured to determine a time of departure of the packet from the second packet handling circuitry utilizing the first TOD domain,

the second packet handling circuitry further configured to set a correction field of the packet to a value based on at least the determined time of departure of the packet from the first microwave station using the second TOD domain and the determined time of arrival of the packet at the first packet handling circuitry utilizing the first TOD domain and further based on at least one of:

the determined time of departure of the packet from the first packet handling circuitry utilizing the first TOD domain;

the determined time of arrival of the packet at the second microwave station utilizing the second TOD domain;

the determined time of arrival of the packet at the second packet handling circuitry utilizing the first TOD domain; and

the determined time of departure of the packet from the second packet handling circuitry utilizing the first TOD domain.

7. The communication system of claim 6 , wherein the first time of day domain and the second time of day domain are independent of one another.

8. The communication system of claim 6 , wherein:

one of the first packet handling circuitry and the second packet handling circuitry is configured to:

determine an expected time of day value for a time in the future at which a periodic signal is to be commonly received or generated by the first packet handling circuitry and the second packet handling circuitry; and

transmit the expected time of day value over the microwave communications link to the other of the first packet handling circuitry or the second packet handling circuitry,

thereby synchronizing the clock of the first packet handling circuitry with the clock of the second packet handling circuitry.

9. The communication system of claim 6 , wherein the microwave communications link comprises a microwave side channel, and wherein said first packet handling circuitry and said second packet handling circuitry are further configured to transmit and receive precision time protocol messages by way of said microwave side channel.

10. The communication system of claim 6 wherein the second packet handling circuitry is arranged to set the correction field of the packet based on all of:

the determined time of departure of the packet from the first packet handling circuitry utilizing the first time day domain;

the determined time of arrival of the packet at the second microwave station utilizing the second time of day domain;

the determined time of arrival of the packet at the second packet handling circuitry utilizing the first time of day domain; and

the determined time of departure of the packet from the second packet handling circuitry utilizing the first time of day domain.

Assignments (19)
RELEASE OF SECURITY INTEREST Recorded Mar 14, 2022
From: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
To: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 060894/0437 →
RELEASE OF SECURITY INTEREST Recorded Mar 11, 2022
From: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
To: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 059363/0001 →
RELEASE OF SECURITY INTEREST Recorded Mar 10, 2022
From: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
To: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 059863/0400 →
RELEASE OF SECURITY INTEREST Recorded Mar 9, 2022
From: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
To: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 059358/0001 →
RELEASE OF SECURITY INTEREST Recorded Feb 25, 2022
From: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
To: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 059333/0222 →
SECURITY INTEREST Recorded Jun 4, 2021
From: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
To: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
Reel/Frame 057935/0474 →
SECURITY INTEREST Recorded Dec 24, 2020
From: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
To: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 055671/0612 →
SECURITY INTEREST Recorded Jun 5, 2020
From: MICROCHIP TECHNOLOGY INC.; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
To: WELLS FARGO BANK, NATIONAL ASSOCIATION
Reel/Frame 053468/0705 →
RELEASE OF SECURITY INTEREST Recorded May 30, 2020
From: JPMORGAN CHASE BANK, N.A, AS ADMINISTRATIVE AGENT
To: MICROCHIP TECHNOLOGY INC.; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 053466/0011 →
SECURITY INTEREST Recorded Apr 24, 2020
From: MICROCHIP TECHNOLOGY INC.; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 053311/0305 →
SECURITY INTEREST Recorded Sep 18, 2018
From: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
To: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
Reel/Frame 047103/0206 →
SECURITY INTEREST Recorded Jun 25, 2018
From: MICROCHIP TECHNOLOGY INCORPORATED; SILICON STORAGE TECHNOLOGY, INC.; ATMEL CORPORATION; MICROSEMI CORPORATION; MICROSEMI STORAGE SOLUTIONS, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 046426/0001 →
RELEASE OF SECURITY INTEREST Recorded May 29, 2018
From: MORGAN STANLEY SENIOR FUNDING, INC.
To: MICROSEMI CORPORATION; MICROSEMI SEMICONDUCTOR (U.S.), INC.; MICROSEMI FREQUENCY AND TIME CORPORATION; MICROSEMI COMMUNICATIONS, INC.; MICROSEMI SOC CORP.; MICROSEMI CORP. - POWER PRODUCTS GROUP; MICROSEMI CORP. - RF INTEGRATED SOLUTIONS
Reel/Frame 046251/0391 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 22, 2017
From: MICROSEMI COMMUNICATIONS, INC.
To: MICROSEMI STORAGE SOLUTIONS, INC.
Reel/Frame 042523/0577 →
PATENT SECURITY AGREEMENT Recorded Feb 3, 2016
From: MICROSEMI CORPORATION; MICROSEMI SEMICONDUCTOR (U.S.) INC. (F/K/A LEGERITY, INC., ZARLINK SEMICONDUCTOR (V.N.) INC., CENTELLAX, INC., AND ZARLINK SEMICONDUCTOR (U.S.) INC.); MICROSEMI FREQUENCY AND TIME CORPORATION (F/K/A SYMMETRICON, INC.); MICROSEMI COMMUNICATIONS, INC. (F/K/A VITESSE SEMICONDUCTOR CORPORATION); MICROSEMI SOC CORP. (F/K/A ACTEL CORPORATION); MICROSEMI CORP. - POWER PRODUCTS GROUP (F/K/A ADVANCED POWER TECHNOLOGY INC.); MICROSEMI CORP. - RF INTEGRATED SOLUTIONS (F/K/A AML COMMUNICATIONS, INC.)
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 037691/0697 →
RELEASE OF SECURITY INTEREST Recorded Jan 19, 2016
From: BANK OF AMERICA, N.A.
To: MICROSEMI CORPORATION; MICROSEMI CORP.-ANALOG MIXED SIGNAL GROUP, A DELAWARE CORPORATION; MICROSEMI SOC CORP., A CALIFORNIA CORPORATION; MICROSEMI SEMICONDUCTOR (U.S.) INC., A DELAWARE CORPORATION; MICROSEMI FREQUENCY AND TIME CORPORATION, A DELAWARE CORPORATION; MICROSEMI COMMUNICATIONS, INC. (F/K/A VITESSE SEMICONDUCTOR CORPORATION), A DELAWARE CORPORATION; MICROSEMI CORP.-MEMORY AND STORAGE SOLUTIONS (F/K/A WHITE ELECTRONIC DESIGNS CORPORATION), AN INDIANA CORPORATION
Reel/Frame 037558/0711 →
MERGER AND CHANGE OF NAME Recorded May 13, 2015
From: VITESSE SEMICONDUCTOR CORPORATION; LLIU100 ACQUISITION CORP.
To: MICROSEMI COMMUNICATIONS, INC.
Reel/Frame 035623/0632 →
SUPPLEMENTAL SECURITY AGREEMENT Recorded Apr 29, 2015
From: MICROSEMI COMMUNICATIONS, INC.
To: BANK OF AMERICA, N.A., AS COLLATERAL AGENT
Reel/Frame 035532/0925 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 16, 2015
From: EHLERS, KRISTIAN; BRANSCOMB, BRIAN; JOERGENSEN, THOMAS KIRKEGAARD
To: VITESSE SEMICONDUCTOR CORPORATION
Reel/Frame 035172/0215 →
Continuity (2)
Continuation 13470092 · May 11, 2012
Related Publication 20140133480A1 · May 15, 2014