LATENCY-AWARE ADAPTIVE BANDWIDTH REQUEST MECHANISM FOR REAL-TIME COMMUNICATION IN WIMAX

• US 20090147737A1
• Filed: 12/10/2007
• Published: 06/11/2009
• Est. Priority Date: 12/10/2007
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Tacconi, Pablo, Agami, Gregory M.
• Granted Patent: US 8,194,556 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 41/0896 Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities flow or congestion control using dynamic resource allocation, e.g. in-call renegotiation, H04L47/76
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/765 triggered by the end-points
• CPC Class Codes: H04L 47/824 Applicable to portable or mobile terminals
• CPC Class Codes: H04L 47/83 based on usage prediction
• CPC Class Codes: H04W 28/20 Negotiating bandwidth

Abstract

A method and apparatus for requesting bandwidth in a subscriber station is disclosed. The method dynamically changes the size of the bandwidth request based on the prediction of the number of packets needed to be transmitted. The average delay experienced by packets in a queue is measured, and this information is then used to change the coefficient of a prediction equation. When the experienced average delay is below the agreed upon QoS latency parameter or delay target, the method reduces the size of the bandwidth requests by making the prediction equation more conservative. On the other hand, when the experienced delay is above the agreed upon latency, the algorithm will make the prediction equation more aggressive, increasing the bandwidth requests and reducing the latency for future packets. By modifying the prediction equation based on the measured delay, the method is able to select the optimal point for achieving time delay requirements while preserving air-link resources.

Claims

9. A subscriber station of a wireless communication system, comprising:

a transceiver capable of transmitting packets to a base station;

a processor capable of determining packet latency from previous transmission; and

controller capable of adjusting the size of a bandwidth request based on the determined packet latency.

10. The subscriber station of claim 9, the subscriber station further comprising:

a scheduler capable of requesting from the base station the adjusted bandwidth request.

11. The subscriber station of claim 10, wherein adjusting is at least one of requesting a bandwidth higher than the previous bandwidth request, requesting a bandwidth lower than the previous bandwidth request, or requesting the previous bandwidth request.

12. The subscriber station of claim 11, wherein bandwidth request is based on packets at the subscriber station at the time of the bandwidth request transmission and a prediction of the packets that will arrive before the bandwidth grant is received.

13. The subscriber station of claim 12, wherein the packet arrival prediction is adjusted based on packet latency.

14. The subscriber station of claim 13, wherein packet latency is the average of the packet delay experienced by the packets at the subscriber station.

15. The subscriber station of claim 14, wherein adjusting is based on a target transmission delay and the determined packet latency.

16. The subscriber station of claim 14, wherein adjusting is proportional to a difference between the target transmission delay and the determined packet latency.

17. An article of manufacture comprising a tangible medium having machine readable instructions stored thereon, the machine readable instructions when executed by a processing platform results in:

transmitting packets to a base station;

determining packet latency from previous packet transmission;

adjusting the size of the bandwidth request based on the determined packet latency; and

requesting from the base station the adjusted bandwidth request.

18-1. The article of claim 18, wherein bandwidth request is based on packets at the subscriber station at the time of the bandwidth request transmission and a prediction of the packets that will arrive before the bandwidth grant is received;

wherein the packet arrival prediction is adjusted based on packet latency;

wherein packet latency is an average of packet delay experienced by the packets at the subscriber station.

19. The article of claim 19, wherein adjusting is based on a target transmission delay and the determined packet latency;

wherein adjusting is proportional to a difference between the target transmission delay and the determined packet latency.