# US 2008/0186849 A1 · Technique for Dynamically Controlling Data Packet Transmissions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0186849 A1 - Document ID: US20080186849A1 - Status: Published application - Kind: A1 - Application number: 11/911,246 - Filed: 2005-04-11 - Published: 2008-08-07 - Earliest claimed: 2005-04-11 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Markus Kampmann; Christoph Plum - Web page: https://patentgrep.com/patent/US20080186849A1 ## CPC - H04L 47/263: Rate modification at the source after receiving feedback - H04L 47/29: {using a combination of thresholds} - H04L 47/30: in combination with information about buffer occupancy at either end or at transit nodes - H04L 65/65: Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP] - H04L 65/70: Media network packetisation - H04L 65/80: Responding to QoS - Y02D 30/50: in wire-line communication networks, e.g. low power modes or reduced link rate - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract A technique is disclosed for controlling data packet transmissions from a server to a client having a client buffer in accordance with a waiting mode and a dynamic mode. The waiting mode is performed before packets containing data encoded subject to a current bit rate have reached the client buffer; the dynamic mode is performed otherwise. In the waiting mode, down-switches to lower bit rates are allowed but up-switches to higher bit rates are disabled. In the dynamic mode, up-switches and down-switches are both allowed, with adjustments in the bit rate of packets controlled based, in part, on the amount of data contained within the client buffer when packets containing data encoded subject to the current bit rate first reached the client buffer. The two modes help avoid unnecessary rate switches. ## Claims ### Claim 1 A method for controlling packet transmissions from a server to a client having a client buffer, wherein a bit rate of data to be transmitted within the packets is selectable by the server based on a status of the client buffer, the method comprising the steps of: starting to transmit packets containing data encoded subject to a current bit rate; monitoring the client buffer to detect when packets containing data encoded subject to the current bit rate first reach the client buffer; detecting a reference value representative of an amount of data within the client buffer when the packets containing data encoded subject to the current bit rate first reached the client buffer; tracking a value representative of an amount of data currently within the client buffer; and controlling adjustments to the bit rate of data being transmitted in accordance with a dynamic mode based on the value representative of the amount of data currently within the client buffer and based on the reference value. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of controlling adjustments in accordance with the dynamic mode includes the step of: switching to a higher bit rate if the amount of data currently within the client buffer exceeds an adjustable up-switch threshold set based on the reference value. ### Claim 3 (depends on 2) The method of claim 2, wherein the adjustable up-switch threshold is set equal to a predetermined safety margin multiplied by the reference value. ### Claim 4 (depends on 2) The method of claim 2, wherein the step of switching to a higher bit rate in the dynamic mode is only performed if the amount of data currently within the client buffer also exceeds a minimum threshold. ### Claim 5 (depends on 1) The method of claim 1, wherein the step of controlling adjustments in accordance with the dynamic mode includes the step of: switching to a lower bit rate if the amount of data currently within the client buffer falls below an adjustable down-switch threshold which is set based on the reference value. ### Claim 6 (depends on 5) The method of claim 5 wherein the adjustable down-switch threshold is set approximately midway between a predetermined minimum threshold and the reference value. ### Claim 7 (depends on 5) The method of claim 5 wherein the step of switching to a lower bit rate in the dynamic mode is alternatively performed if the amount of data currently within the client buffer falls below the predetermined minimum threshold. ### Claim 8 (depends on 6) The method of claim 6 wherein the minimum threshold is a fixed down-switch threshold. ### Claim 9 (depends on 1) The method of claim 1 wherein the step of controlling adjustments in the bit rate of packets in accordance with the dynamic mode is only performed after packets sent containing data encoded subject to the current bit rate have reached the client buffer. ### Claim 10 (depends on 9) The method of claim 9, further including the step of controlling further adjustments in the bit rate of data in accordance with a waiting mode. ### Claim 11 (depends on 10) The method of claim 10, wherein the step of controlling further adjustments in the bit rate of data in accordance with the waiting mode is only performed after a rate adjustment and before packets sent containing data encoded subject to a newly adjusted bit rate have reached the client buffer. ### Claim 12 (depends on 11) The method of claim 11, wherein the step of controlling further adjustments in the bit rate of packets in accordance with the waiting mode includes the step of: switching to a lower bit rate if the amount of data currently within the client buffer falls below a fixed down-switch threshold. ### Claim 13 (depends on 11) The method of claim 11 wherein the step of controlling further adjustments in the bit rate of packets in accordance with the waiting mode includes the step of: disabling increases in the bit rate. ### Claim 14 (depends on 1) The method of claim 1, wherein the value representative of the amount of data within the client buffer is representative of a playout length of the data or a buffer fill level. ### Claim at position 15 15-17. (canceled) ### Claim 18 An apparatus for controlling packet transmissions from a server to a client having a client buffer, wherein a bit rate of packets from the server to the client is adjustable by the server based on a current status of the client buffer, the apparatus comprising: a bit rate controller for starting to transmit data in packets at a current bit rate; a client buffer monitor for monitoring the client buffer to detect when packets containing data encoded subject to the current bit rate first reach the client buffer and for detecting a reference value representative of an amount of data within the client buffer when the packets containing data encoded subject to the current bit rate first reached the client buffer; a tracking unit for backing a value representative of an amount of data currently within the client buffer; and a dynamic mode controller for controlling adjustments in the bit rate of packets based on the value representative of the amount of data currently within the client buffer and based on the reference value.