TRANSMISSION ADAPTATION IN A WIRELESS NETWORK

• US 20120113856A1
• Filed: 01/16/2012
• Published: 05/10/2012
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Dilip Krishnaswamy
• Original Assignee: Dilip Krishnaswamy
• Inventors: Krishnaswamy, Dilip
• Granted Patent: US 8,379,552 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/3065 for real time traffic
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 65/752 adapting media to network capabilities
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04W 28/22 Negotiating communication rate

Abstract

An arrangement is provided for adapting the output bit rate of a multimedia source to the bandwidth available in a wireless network. Depending on the value of the available network idle time, at least a portion of the available network idle time may be used by the source to increase its output bit rate so that the network bandwidth may be more efficiently utilized. If the effective throughput of the network after the increase of source output bit rate drops significantly, the source may reduce its output bit rate until the effective throughput returns to the level before the source output bit rate increase. Additionally, packet delay and queue jitter information may be collected and used for queue rate adaptation as well as bandwidth adaptation.

Claims

1. An apparatus for performing wireless transmission adaptation in a wireless network, the apparatus comprising:

at least one memory unit; and

at least one processor operably coupled to the at least one memory unit and configured to operably execute instructions associated with a set of modules, the set of modules including;

a path selector module arranged to receive a request from a data source to transmit data from a source node to a destination node and to select a transmission path for transmission of packets between the source node and the destination node through a coordinator node in a wireless network, the wireless network being a packet switched wireless network and implementing a collision avoidance protocol;

a statistics collection module at the coordinator node arranged to track a contribution of each node in the transmission path to traffic in the wireless network; and

a wireless transmission adaptation module arranged to determine one or more variable backoff time values for each node in the transmission path, and to provide the variable backoff time values from the coordinator node to the source node and to each node in the transmission path, wherein the variable backoff time values for a particular node are increased based on a higher contribution of the particular node to traffic in the wireless network and decreased based on a lower contribution of the particular node to traffic in the wireless network;

wherein a transmission of the data on the wireless network from the source node and each node in the transmission path is performed in connection with use of the variable backoff time values.

2. The apparatus of claim 1, wherein to select a transmission path from the source node to the destination node, the path selector module is arranged to identify available transmission paths from the source node to the destination node, select a set of candidate paths among the available transmission paths, and select, in the set of candidate paths, one that provides a highest throughput between the source node and the destination node as the transmission path, wherein each candidate path in the set of candidate paths meets requirements of delay between the source node and the destination node provided by the data source.

3. The apparatus of claim 1, further comprising:

a bandwidth adaptation module arranged to adapt an output bit rate of the data source to available bandwidth on the wireless network based on the contribution of each node in the transmission path to traffic in the wireless network.

4. The apparatus of claim 3, wherein the bandwidth adaptation module is arranged to determine the available bandwidth based on network idle time, wherein the network idle time is an amount of time when there are no packetized transmissions over a wireless channel of the wireless network detected by the coordinator node and when the coordinator node is not in a wireless transmission backoff stage, and wherein the bandwidth adaptation module is arranged to increase the output bit rate by using a portion of the network idle time if the network idle time is larger than a predetermined minimum idle time value, to monitor an effective throughput of the network after increasing the output bit rate, and to reduce the output bit rate if the effective throughput drops and the amount of the effective throughput reduction exceeds a predetermined threshold.

5. A coordinator device node, comprising:

at least one processor; and

at least one memory unit, the at least one memory unit providing a plurality of instructions that, in response to being executed by the at least one processor, cause the coordinator device node to perform operations that;

track a contribution of each device node in a transmission path to traffic in the wireless network, the transmission path provided from a source device node to a destination device node through the coordinator device node in a packet switched wireless network implementing a collision avoidance protocol;

determine one or more variable backoff time values for each device node in the transmission path, the variable backoff time values for a particular device node being increased based on a higher contribution of the particular device node to traffic in the wireless network; and

provide the variable backoff time values to the source device node and each device node in the transmission path;

wherein data on the wireless network is transmitted with use of the variable backoff time values at the source device node and each device node in the transmission path.

6. The coordinator device node of claim 5, wherein at least one of the variable backoff time values is provided as a backoff counter value used to provide backoff for a corresponding number of backoff time periods, and wherein the variable backoff time values for device nodes in the transmission path are increased based on a higher contribution of a particular device node to traffic in the wireless network and decreased based on a lower contribution of a particular device node to traffic in the wireless network.

7. The coordinator device node of claim 5, wherein the coordinator device node further performs operations that:

adapt an output bit rate of the data source to available bandwidth on the wireless network based on the contribution of each device node in the transmission path to traffic in the wireless network.

8. The coordinator device node of claim 7, wherein operations that adapt the output bit rate of the data source to the available bandwidth are performed after each period of measurement time and include:

determining the available bandwidth based at least in part on network idle time, wherein the network idle time is an amount of time when there are no packetized transmissions over a wireless channel of the wireless network detected by the coordinator device node and when the coordinator device node is not in a wireless transmission backoff stage;

increasing the output bit rate by using at least a portion of the network idle time if the network idle time is larger than a predetermined minimum idle time value;

monitoring an effective throughput of the wireless network after increasing the output bit rate; and

if the effective throughput drops and the amount of the effective throughput reduction exceeds a predetermined threshold, reducing the output bit rate;

wherein adapting the output bit rate of the data source to the available bandwidth is performed incrementally.

9. A full function device node operable in a wireless network, the full function device node comprising:

at least one processor; and

at least one memory unit, the at least one memory unit providing a plurality of instructions that, in response to being executed by the at least one processor, cause the full function device node to perform operations that;

process a request to forward data in the wireless network from a source device node to a destination device node along a transmission path through the full function device node, the wireless network being a packet switched wireless network implementing a collision avoidance protocol;

receive one or more variable backoff time values from a coordinator full function device node providing variable backoff time values to each device node along the transmission path;

implement the variable backoff time values, wherein the variable backoff time values for the full function device node are determined by the coordinator full function device node and are increased based on a higher contribution of the full function device node to traffic in the wireless network and decreased based on a lower contribution of the full function device node to traffic in the wireless network; and

perform data transmissions from the full function device node with use of the variable backoff time values.

10. The full function device node of claim 9, wherein at least one of the variable backoff time values is provided as a backoff counter value used to provide backoff for a corresponding number of backoff time periods.

11. A method for wireless transmission adaptation in a wireless network, the method comprising:

receiving, at a coordinator node, a request from a data source to transmit data from a source node to a destination node in a packet switched wireless network implementing a collision avoidance protocol;

selecting a transmission path for transmission of packets of the data from the source node to the destination node through the coordinator node;

tracking, at the coordinator node, a contribution of each node in the transmission path to traffic in the wireless network;

determining one or more variable backoff time values differing for each node in the transmission path, the variable backoff time values for a particular node being increased based on a higher contribution of the particular node to traffic in the wireless network;

providing the variable backoff time values from the coordinator node to the source node and each node in the transmission path; and

performing a transmission of the data on the wireless network from the source node and each node in the transmission path in connection with use of the variable backoff time values.

12. The method of claim 11, wherein at least one of the variable backoff time values is provided as a backoff counter value used to provide backoff for a corresponding number of backoff time periods.

13. The method of claim 11, wherein the variable backoff time values for nodes in the transmission path are increased based on a higher contribution of a particular node to traffic in the wireless network and decreased based on a lower contribution of a particular node to traffic in the wireless network.

14. The method of claim 11, wherein selecting a transmission path from the source node to the destination node comprises:

identifying available transmission paths from the source node to the destination node;

selecting a set of candidate paths among the available transmission paths, each candidate path meeting requirements of delay between the source node and the destination node provided by the data source (“

source end-to-end delay requirement”

); and

selecting, from the set of candidate paths, a candidate path that provides a highest throughput between the source node and the destination node as the transmission path.

15. The method of claim 14, further comprising:

determining an initial transmission rate for the data source based on the source end-to-end delay requirements and network characteristics; and

transmitting the data using the initial transmission rate as an output bit rate of the data source.

16. The method of claim 15, wherein the network characteristics comprise transmission channels and a transmission protocol used by the wireless network.

17. The method of claim 11, further comprising:

adapting an output bit rate of the data source to available bandwidth on the wireless network based on the contribution of each node in the transmission path to traffic in the wireless network.

18. The method of claim 17, wherein adapting the output bit rate of the data source to the available bandwidth on the wireless network comprises:

determining the available bandwidth based at least in part on network idle time, wherein the network idle time is an amount of time when there are no packetized transmissions over a wireless channel of the wireless network detected by the coordinator node and when the coordinator node is not in a wireless transmission backoff stage; and

increasing the output bit rate by using at least a portion of the network idle time if the network idle time is larger than a predetermined minimum idle time value.

19. The method of claim 18, further comprising:

monitoring an effective throughput of the wireless network after increasing the output bit rate; and

if the effective throughput drops and the amount of the effective throughput reduction exceeds a predetermined threshold, reducing the output bit rate;

wherein adapting the output bit rate of the data source to the available bandwidth is performed incrementally.

20. The method of claim 19, further comprising performing transmission queue rate adaptation after a period of measurement time based at least on packet delay and queue statistics collected during the period of measurement time.