Re-timing a packetized radio flow to clean noise induced by packet delay variation of a packet network

Patent metadata

Field	Value
Publication number	US-11095384-B2
Application number	US-202016751509-A
Country	US
Kind code	B2
Filing date	Jan 24, 2020
Priority date	Sep 9, 2019
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

Techniques are described to provide for re-timing a packetized radio flow to clean noise induced by packet delay variation of a packet network. In one example, a method includes receiving, at a first node of a fronthaul network, a Radio over Ethernet (RoE) frame transmitted by a second node in which the RoE frame comprises a Common Public Radio Interface (CPRI) bit stream associated with a first radio device, a sequence number, and a first time stamp. The method may further include generating a second time stamp by the first node upon obtaining the RoE frame; calculating an induced delay value based, at least in part, on the first time stamp and the second time stamp; calculating a re-timing value based on a re-timing interval and the induced delay value; and transmitting the CPRI bit stream to a second radio device based on the re-timing value.

First claim

What is claimed is:

1. A method comprising:
obtaining a Radio over Ethernet (RoE) frame, wherein the RoE frame comprises a Common Public Radio Interface (CPRI) bit stream and a first time stamp;
determining an induced delay value associated with the RoE frame, wherein determining the induced delay value includes comparing a seconds-bit of the first time stamp to a seconds-bit of a second time stamp generated when the RoE frame is obtained to determine whether a second rollover has occurred and wherein based on determining that a second rollover has not occurred, the induced delay value is determined by calculating a difference between the first time stamp and the second time stamp, and based on determining that a second rollover has occurred, the induced delay value is determined by calculating a difference between a maximum counter value and the first time stamp and adding the second time stamp to the difference;
calculating a re-timing value based on a difference between a re-timing interval and the induced delay value; and
transmitting the CPRI bit stream based on the re-timing value.

2. The method of claim 1 , wherein the transmitting is performed using a re-timer buffer.

3. The method of claim 1 , wherein at least one of:
a sequence number and the first time stamp are contained within an ordering information field of the RoE frame;
the first time stamp is contained within a fixed-sized RoE extension header; and
the first time stamp is contained with a variable-sized RoE extension header list.

4. The method of claim 3 , wherein the first time stamp is contained within a q-bits counter field comprising the ordering information field and the sequence number is contained within a p-bits counter field comprising of the ordering information field.

5. The method of claim 4 , wherein the q-bits counter field is 16-bits and the p-bits counter field is 12-bits.

6. The method of claim 4 , wherein a most significant bit of the q-bits counter field represents a seconds-bit and a remaining number of bits of the q-bits counter field represent a microsecond counter value.

7. The method of claim 1 , wherein the RoE frame is obtained from a packet-switched network.

8. The method of claim 7 , wherein the re-timing interval is based on a maximum packet delay variation (PDV) of the packet-switched network.

9. One or more non-transitory computer readable storage media encoded with instructions that, when executed by a processor, cause the processor to perform operations, comprising:
obtaining a Radio over Ethernet (RoE) frame, wherein the RoE frame comprises a Common Public Radio Interface (CPRI) bit stream and a first time stamp;
determining an induced delay value associated with the RoE frame, wherein determining the induced delay value includes comparing a seconds-bit of the first time stamp to a seconds-bit of a second time stamp generated when the RoE frame is obtained to determine whether a second rollover has occurred and wherein based on determining that a second rollover has not occurred, the induced delay value is determined by calculating a difference between the first time stamp and the second time stamp, and based on determining that a second rollover has occurred, the induced delay value is determined by calculating a difference between a maximum counter value and the first time stamp and adding the second time stamp to the difference;
calculating a re-timing value based on a difference between a re-timing interval and the induced delay value; and
transmitting the CPRI bit stream based on the re-timing value.

10. The media of claim 9 , wherein at least one of:
a sequence number and the first time stamp are contained within an ordering information field of the RoE frame;
the first time stamp is contained within a fixed-sized RoE extension header; and
the first time stamp is contained with a variable-sized RoE extension header list.

11. The media of claim 10 , wherein the first time stamp is contained within a q-bits counter field comprising the ordering information field and the sequence number is contained within a p-bits counter field comprising of the ordering information field.

12. The media of claim 11 , wherein a most significant bit of the q-bits counter field represents a seconds-bit and a remaining number of bits of the q-bits counter field represent a microsecond counter value.

13. The media of claim 9 , wherein the re-timing interval is based on a maximum packet delay variation (PDV) of a packet-switch network from which the RoE frame is obtained.

14. A system comprising:
at least one memory element for storing data; and
at least one processor for executing instructions associated with the data, wherein executing the instructions causes the system to perform operations, comprising:
obtaining a Radio over Ethernet (RoE) frame, wherein the RoE frame comprises a Common Public Radio Interface (CPRI) bit stream and a first time stamp;
determining an induced delay value associated with the RoE frame, wherein determining the induced delay value includes comparing a seconds-bit of the first time stamp to a seconds-bit of a second time stamp generated when the RoE frame is obtained to determine whether a second rollover has occurred and wherein based on determining that a second rollover has not occurred, the induced delay value is determined by calculating a difference between the first time stamp and the second time stamp and based on determining that a second rollover has occurred, the induced delay value is determined by calculating a difference between a maximum counter value and the first time stamp and adding the second time stamp to the difference;
calculating a re-timing value based on a difference between a re-timing interval and the induced delay value; and
transmitting the CPRI bit stream based on the re-timing value.

15. The system of claim 14 , wherein the transmitting is performed using a re-timer buffer.

16. The system of claim 14 , wherein at least one of:
a sequence number and the first time stamp are contained within an ordering information field of the RoE frame;
the first time stamp is contained within a fixed-sized RoE extension header; and
the first time stamp is contained with a variable-sized RoE extension header list.

17. The system of claim 16 , wherein the first time stamp is contained within a q-bits counter field comprising the ordering information field and the sequence number is contained within a p-bits counter field comprising of the ordering information field.

18. The system of claim 17 , wherein the q-bits counter field is 16-bits and the p-bits counter field is 12-bits.

19. The system of claim 17 , wherein a most significant bit of the q-bits counter field represents a seconds-bit and a remaining number of bits of the q-bits counter field represent a microsecond counter value.

20. The system of claim 14 , wherein the re-timing interval is based on a maximum packet delay variation (PDV) of a packet-switched network from which the RoE frame is obtained.

Assignees

• Cisco Tech Inc

Inventors

• Anand Prashant
• Kayamkulangara Sudhir
• K Dinuraj
• Boopalan Manigandan
• Kumar Manoj

Classifications

• H04L47/35

  by embedding flow control information in regular packets, e.g. piggybacking · CPC title

• H04J3/0682

  by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging · CPC title

• H04L47/28

  in relation to timing considerations · CPC title

• H04J3/0664 Primary

  unidirectional timestamps · CPC title

• H04J3/0655

  using timestamps · CPC title