# US 8,570,986 B2 · Semi-random back-off method for achieving resource reservation in wireless local area networks

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,570,986 B2
- Document ID: US8570986B2
- Status: Granted
- Kind: B2
- Application number: 13/386,923
- Filed: 2010-07-13
- Published: 2012-05-24
- Granted: 2013-10-29
- Earliest claimed: 2009-07-29
- Assignees: Thomson Licensing
- Applicants: Yong He; Xiao-jun Ma; Jun Li
- Inventors: Yong He; Xiao-jun Ma; Jun Li
- Web page: https://patentgrep.com/patent/US8570986B2

## CPC

- H04W 74/085: {collision avoidance}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method and apparatus are described including determining if a successful unicast transmission has occurred, adjusting a contention window to a minimum value and adjusting a time slot back-off counter to one-half of the value of the contention window plus one responsive to the determination and adjusting the contention window using one of a plurality of adjustment schemes and selecting said time slot back-off counter from an interval between zero and the contention window.

## Claims

### Claim 1

A method, said method comprising:
determining if a successful unicast transmission has occurred;
if a successful unicast transmission has occurred, adjusting a contention window to a minimum value and adjusting a time slot back-off counter to one-half of the value of said contention window plus one;
adjusting a service ring size responsive to said time slot back-off counter; and
adjusting said contention window using one of a plurality of adjustment schemes and selecting said time slot back-off counter from an interval between zero and said contention window.

### Claim 2 (depends on 1)

The method according to claim 1 wherein said adjustment schemes include binary exponential back-off, multiplicative increase linear decrease, exponential increase exponential decrease and linear increase linear decrease.

### Claim 3 (depends on 1)

The method according to claim 1 further comprising:
determining if there is more data to transmit; and
transmitting said data responsive to said determination.

### Claim 4

An apparatus comprising:
means for determining if a successful unicast transmission has occurred;
means for adjusting a contention window to a minimum value and adjusting a time slot back-off counter to one-half of the value of said contention window plus one if a successful unicast transmission has occurred;
means for adjusting a service ring size responsive to said time slot back-off counter; and
means for adjusting said contention window using one of a plurality of adjustment schemes and selecting said time slot back-off counter from an interval between zero and said contention window.

### Claim 5 (depends on 4)

The apparatus according to claim 4, wherein said apparatus is one of a mobile device, a server and a base station.

### Claim 6 (depends on 4)

The apparatus according to claim 4, further comprising:
means for determining if there is more data to transmit; and
means for transmitting said data responsive to said determination.