Quality of service scheme for collision-based wireless networks

• US 20100067451A1
• Filed: 09/16/2008
• Published: 03/18/2010
• Est. Priority Date: 09/16/2008
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Hall, Robert J.
• Granted Patent: US 9,544,922 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 74/0875 with assigned priorities based access

Abstract

A method for enabling different priority messages in a contention-based wireless network where units use a common channel. Relative to high priority messages, if the channel is not busy when a message is ready for transmission, then the message is transmitted immediately. When the channel is busy, the message is not transmitted until the channel becomes available and a selected back-off period (while the channel is available) expires. Back off periods are illustratively randomly selected by the units. Low priority messages are similarly not transmitted when the channel is busy, and additionally are not transmitted for a preselected pre-emption interval when the channel is available to high priority messages but not to low priority messages. Like with high priority messages, low priority messages that not transmitted when ready are held back a back-off period before they are transmitted.

Claims

1. A method for transmitting a message over a channel in an environment where a plurality of units may transmit over said channel, said message having a priority lower than a highest priority of messages are possible to be transmitted over said channel, comprising the steps of:

determining whether said channel is busy or is in midst of a low priority pre-emption interval (LPPI) that occurs following a transition from said channel being busy to said channel being not busy, said LPPI having a duration that is related to said priority of said message;

if said step of determining concludes that said channel is busy, waiting till said channel becomes not busy, and till said LPPI expires;

if said step of determining concludes that said channel is in midst of said LPPI, waiting till said LPPI expires; and

transmitting said message after said LPPI expires.

2. The method of claim 1 where said LPPI advances in time toward expiration, but only when said channel is not busy.

3. The method of claim 1 where said LPPI expires when said channel is not busy, and said transmitting of said message commences immediately thereafter, while the channel is not busy.