# US 11,909,644 B2 · Transport congestion control optimization based on network context

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- Number: US 11,909,644 B2
- Document ID: US11909644B2
- Status: Granted
- Kind: B2
- Application number: 17/510,502
- Filed: 2021-10-26
- Published: 2022-02-10
- Granted: 2024-02-20
- Earliest claimed: 2019-11-26
- Assignees: Verizon Patent and Licensing Inc.
- Applicants: Verizon Patent and Licensing Inc.
- Inventors: Daniel Mindler; Hugo David Munoz Sanchez; Maria Cel Halili Zaballero; Daniel Osorio; Xihong Wang; Lixia Yan
- Web page: https://patentgrep.com/patent/US11909644B2

## CPC

- H04L 43/0864: Round trip delays
- H04L 41/5067: Customer-centric QoS measurements
- H04L 43/0876: Network utilisation, e.g. volume of load or congestion level
- H04L 43/16: Threshold monitoring
- H04W 28/0273: {adapting protocols for flow control or congestion control to wireless environment, e.g. adapting transmission control protocol [TCP] (wireless network protocols or protocol adaptations to wireless operation, e.g. wireless application protocol H04W80/00)}
- H04W 28/0289: {Congestion control (load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12)}
- H04W 40/36: due to handover
- H04W 72/20: Control channels or signalling for resource management
- 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)

## Abstract

A network device transmits data to a user equipment (UE) via a first Radio Access Network (RAN) using first Transmission Control Protocol (TCP) congestion control parameters. The network device receives a notification message indicating that the UE has moved from the first RAN to a second RAN. The network device modifies, responsive to receipt of the notification, the first TCP congestion control parameters to create second TCP congestion control parameters, where the first TCP congestion control parameters include a first slow start threshold (ssthresh), and wherein the second TCP congestion control parameters include a second ssthresh that is different than the first ssthresh. The network device transmits data to the UE via the second RAN using the second TCP congestion control parameters.

## Claims

### Claim 1

A method, comprising:
transmitting, from a network device, first data to a user equipment (UE) via a Long-Term Evolution (LTE) Radio Access Network (RAN) using Transmission Control Protocol (TCP) congestion control parameters, wherein the TCP congestion control parameters comprise a segment size parameter (segsize) associated with a TCP congestion window (CWND) and a slow start threshold parameter (ssthresh) associated with a slow start phase of TCP congestion control;
receiving, by the network device, a notification message indicating that the UE has moved from the LTE RAN to a Next Generation RAN;
increasing, by the network device responsive to receipt of the notification message indicating that the UE has moved from the LTE RAN to the Next Generation RAN, a value of the segsize while simultaneously decreasing the ssthresh such that the CWND increments at a faster rate over a shorter period of time; and
transmitting, from the network device, second data to the UE via the Next Generation RAN using the increased segsize and the decreased ssthresh of the TCP congestion control parameters.

### Claim 2 (depends on 1)

The method of claim 1, wherein the ssthresh controls a period, associated with the CWND, over which a rate of transmission of the second data is increased.

### Claim 3 (depends on 1)

The method of claim 1, wherein the network device comprises a gateway or router that establishes a TCP proxy between a data source and the UE.

### Claim 4 (depends on 1)

The method of claim 1, wherein increasing the value of the segsize while simultaneously decreasing the ssthresh ramps up, during the slow start phase of the TCP congestion control, the transmitting of the second data from the network device to utilize a higher bandwidth associated with the Next Generation RAN.

### Claim 5 (depends on 1)

The method of claim 1, wherein CWND is a current size of the TCP congestion window, the segsize comprises a value used to increment a size of CWND when each ACK is received, the ssthresh comprises a current value for a slow start threshold associated with the slow start phase of TCP congestion control that controls a length of the shorter period of time over which the CWND increments at the faster rate.

### Claim 6 (depends on 1)

The method of claim 1, wherein the slow start phase comprises:
when CWND is less than or equal to ssthresh, then each time an ACK is received, CWND is incremented by the segsize (CWND=CWND+segsize),
wherein CWND is a current size of the TCP congestion window,
segsize is a current value used to increment a size of CWND when each ACK is received,
ssthresh is a current value for the slow start threshold, and
ACK is a respective acknowledgement message received in response to the network device sending each block of the second data to the UE.

### Claim 7

A network device, comprising:
at least one communication interface to:
transmit first data to a user equipment (UE) via a Long-Term Evolution (LTE) Radio Access Network (RAN) using Transmission Control Protocol (TCP) congestion control parameters, wherein the TCP congestion control parameters comprise a segment size parameter (segsize) associated with a TCP congestion window (CWND) and a slow start threshold parameter (ssthresh) associated with a slow start phase of TCP congestion control, and
receive a notification message indicating that the UE has moved from the LTE RAN to a Next Generation RAN; and
a processor, or logic, that increases, responsive to receipt of the notification message indicating that the UE has moved from the LTE RAN to the Next Generation RAN, a value of the segsize while simultaneously decreasing the ssthresh such that the CWND increments at a faster rate over a shorter period of time;
wherein the at least one communication interface further transmits second data to the UE via the Next Generation RAN using the increased segsize and the decreased ssthresh of the TCP congestion control parameters.

### Claim 8 (depends on 7)

The network device of claim 7, wherein the ssthresh controls a period, associated with the CWND, over which a rate of transmission of the second data is increased.

### Claim 9 (depends on 7)

The network device of claim 7, wherein the network device comprises a gateway or router that establishes a TCP proxy between a data source and the UE.

### Claim 10

A non-transitory storage medium storing instructions executable by a network device with one or more processors, wherein execution of the instructions causes the network device to:
transmit first data to a user equipment (UE) via a Long-Term Evolution (LTE) Radio Access Network (RAN) using Transmission Control Protocol (TCP) congestion control parameters, wherein the TCP congestion control parameters comprise a segment size parameter (segsize) associated with a TCP congestion window (CWND) and a slow start threshold parameter (ssthresh) associated with a slow start phase of TCP congestion control;
receive a notification message indicating that the UE has moved from the LTE RAN to a Next Generation RAN;
increase, responsive to receipt of the notification message indicating that the UE has moved from the LTE RAN to the Next Generation RAN, a value of the segsize while simultaneously decreasing the ssthresh such that the CWND increments at a faster rate over a shorter period of time; and
transmit second data to the UE via the Next Generation RAN using the increased segsize and the decreased ssthresh of the TCP congestion control parameters.

### Claim 11 (depends on 10)

The non-transitory storage medium of claim 10, wherein the ssthresh controls a period associated with the CWND, over which a rate of transmission of the second data is increased.

### Claim 12 (depends on 10)

The non-transitory storage medium of claim 10, wherein the network device comprises a gateway or router that establishes a TCP proxy between a data source and the UE.

### Claim 13

A method, comprising:
transmitting, from a network device, first data to a user equipment (UE) via a Next Generation Radio Access Network (RAN) using Transmission Control Protocol (TCP) congestion control parameters, wherein the TCP congestion control parameters comprise a segment size parameter (segsize) associated with a TCP congestion window (CWND) and a slow start threshold parameter (ssthresh) associated with a slow start phase of TCP congestion control;
receiving, by the network device, a notification message indicating that the UE has moved from the Next Generation RAN to a Long-Term Evolution (LTE) RAN;
increasing, by the network device responsive to receipt of the notification message indicating that the UE has moved from the Next Generation RAN to the LTE RAN, a value of the segsize while simultaneously decreasing the ssthresh such that the CWND decrements at a faster rate over a shorter period of time; and
transmitting, from the network device, second data to the UE via the LTE RAN using the increased segsize and the decreased ssthresh of the TCP congestion control parameters.

### Claim 14 (depends on 13)

The method of claim 13, wherein CWND is a current size of the TCP congestion window, the segsize comprises a value used to decrement a size of CWND when each ACK is received, the ssthresh comprises a current value for a slow start threshold associated with the slow start phase of TCP congestion control that controls a length of the shorter period of time over which the CWND decrements at the faster rate.

### Claim 15 (depends on 13)

The method of claim 13, wherein the slow start phase comprises:
when CWND is less than or equal to ssthresh, then each time an ACK is received, CWND is decremented by the segsize (CWND=CWND−segsize),
wherein CWND is a current size of the TCP congestion window,
segsize is a current value used to decrement a size of CWND when each ACK is received,
ssthresh is a current value for the slow start threshold, and
ACK is a respective acknowledgement message received in response to the network device sending each block of the second data to the UE.

### Claim 16 (depends on 13)

The method of claim 13, wherein the ssthresh controls a period, associated with the CWND, over which a rate of transmission of the second data is decreased.

### Claim 17

A network device, comprising:
at least one communication interface to:
transmit first data to a user equipment (UE) via a Next Generation Radio Access Network (RAN) using Transmission Control Protocol (TCP) congestion control parameters, wherein the TCP congestion control parameters comprise a segment size parameter (segsize) associated with a TCP congestion window (CWND) and a slow start threshold parameter (ssthresh) associated with a slow start phase of TCP congestion control, and
receive a notification message indicating that the UE has moved from the Next Generation RAN to a Long-Term Evolution (LTE) RAN; and
a processor, or logic, that increases, responsive to receipt of the notification message indicating that the UE has moved from the Next Generation RAN to the LTE RAN, a value of the segsize while simultaneously decreasing the ssthresh such that the CWND decrements at a faster rate over a shorter period of time;
wherein the at least one communication interface further transmits second data to the UE via the LTE RAN using the increased segsize and the decreased ssthresh of the TCP congestion control parameters.

### Claim 18 (depends on 17)

The network device of claim 17, wherein the ssthresh controls a period, associated with the CWND, over which a rate of transmission of the second data is decreased.

### Claim 19 (depends on 17)

The network device of claim 17, wherein CWND is a current size of the TCP congestion window, the segsize comprises a value used to decrement a size of CWND when each ACK is received, the ssthresh comprises a current value for a slow start threshold associated with the slow start phase of TCP congestion control that controls a length of the shorter period of time over which the CWND decrements at the faster rate.

### Claim 20 (depends on 17)

The network device of claim 17, wherein the slow start phase comprises:
when CWND is less than or equal to ssthresh, then each time an ACK is received, CWND is decremented by the segsize (CWND=CWND−segsize),
wherein CWND is a current size of the TCP congestion window,
segsize is a current value used to decrement a size of CWND when each ACK is received,
ssthresh is a current value for the slow start threshold, and
ACK is a respective acknowledgement message received in response to the network device sending each block of the second data to the UE.