Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Collision avoidance in IEEE 802.11 contention free period (CFP) with overlapping basic service sets (BSSs)

a technology of overlapping basic service sets and avoiding collisions, which is applied in the field of wireless network protocols, can solve the problems of physical limitations of physical networks, and limited access to network nodes, and achieve the effect of facilitating the effectiveness of hardware or softwar

Inactive Publication Date: 2006-02-09
CERVELLO GERARD +1
View PDF10 Cites 91 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0023] It is yet another object of the present invention to define a new counter called Overlapping Network Allocation Vector (ONAV) to render the RTS / CTS during CFP truly effective even in the existence of the STAs in CFP in the case of overlapping BSSs.
[0024] It is still yet another aspect of the invention to provide a hybrid wireless MAC protocol for isochronous traffic support which uses a novel Ready To Send(RTS) / Clear T o Send(CTS) exchange during a contention free period (CFP) in order to avoid contention from Stations (STAs) in overlapping BSSs, combined with a new counter called Overlapping Network Allocation Vector (ONAV) to render the RTS / CTS during CFP truly effective even in the existence of the STAs in CFP in the case of overlapping BSSs. To that end, the present invention sets forth a medium access control (MAC) protocol for avoiding collisions from stations (STAs) comprising two or more IEEE 802.11 basic service sets (BSSs) collocated and operating in the same channel during contention free periods (CFPs). The MAC protocol includes hardware or software for utilizing request-to-send(RTS) / clear-to-send(CTS) exchange during CFPs to avoid potential collision from STAs in overlapping BSSs and hardware or software for providing overlapping network allocation vectors (ONAV) in addition to a network allocation vector (NAV), the ONAV included to facilitate the effectiveness of the hardware or software for utilizing.
[0026] A third embodiment of the present invention provides a method for avoiding collisions from stations (STAs) comprising two or more IEEE 802.11 basic service sets (BSSs) collocated and operating in the same channel during contention free periods (CFPs). The MAC protocol includes hardware or software for utilizing request-to-send(RTS) / clear-to-send(CTS) exchange during CFPs to avoid potential collision from STAs in overlapping BSSs. The method may further include steps for providing an overlapping network allocation vectors (ONAV) in addition to a network allocation vector (NAV), the ONAV included to facilitate the effectiveness of the collision avoidance.

Problems solved by technology

Until recently, however, LANs were limited to physical, hard-wired (wireline) infrastructure.
Even with phone dial-ups, network nodes were limited to access through wireline connections.
A problem will arise in the case where two (2) STAs sense the medium as being free, for example, contemporaneously, and each transmit a data packet at the same time resulting in a collision.
Note that in wireless environment, transmitting and receiving at the same time is almost impossible even with a full duplex radio due to the high signal attenuation.
Moreover, in such a wireless LAN system, not all STAs can “hear” each other.
As the reader can guess, this is certainly not a complete solution to the above-stated problem.
Moreover, radio transmissions based on IEEE 802.11 may also be ineffective because transmitting nodes within the wireless LAN cannot hear any other node in the system (network) which may be transmitting.
The problem can be analogized to the problem of hearing impairment, that is, some nodes are hearing impaired for any of various reasons.
Hidden nodes or stations (STAs) prevent efficient use of bandwidth as a result of their hearing impairment to certain transmissions.
This kind of collision during the CFP can result in severe degradation of the effectiveness of the PCF in terms of the throughput, and it makes really difficult to support QoS using this polling-based PCF.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Collision avoidance in IEEE 802.11 contention free period (CFP) with overlapping basic service sets (BSSs)
  • Collision avoidance in IEEE 802.11 contention free period (CFP) with overlapping basic service sets (BSSs)
  • Collision avoidance in IEEE 802.11 contention free period (CFP) with overlapping basic service sets (BSSs)

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0035] Said first embodiment may further comprise a new counter called Overlapping Network Allocation Vector (ONAV) to render the RTS / CTS during CFP truly effective even in the existence of the STAs in CFP in the case of overlapping BSSs.

third embodiment

[0036] the invention provides a hybrid wireless MAC protocol for isochronous traffic support which uses a novel Ready To Send(RTS) / Clear To Send(CTS) exchange during a contention free period (CFP) in order to avoid contention from Stations (STAs) in overlapping BSSs, combined with a new counter called Overlapping Network Allocation Vector (ONAV) to render the RTS / CTS during CFP truly effective even in the existence of the STAs in CFP in the case of overlapping BSSs.

[0037] More particularly, the inventions disclosed herein utilize a work frame which could included and used in a conventional WLAN such as that shown in FIG. 1. Within the invention, the network frame starts with a beacon transmission from the access point (AP) to all the stations (STA) in the receiving range of the AP (as shown in FIGS. 2 and 3). The beacon includes the information about the time slot allocation for each STA, synchronization information and information about the AP itself, which is necessary for new STA...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A medium access control (MAC) protocol is provided for avoiding collisions from stations (STAs) comprising two or more IEEE 802.11 basic service sets (BSSs) collocated and operating in the same channel during contention free periods (CFPs). The MAC protocol includes hardware / software for utilizing ready-to-send (RTS) / clear-to-send(CTS) exchange during CFPs to avoid potential collision from STAs in overlapping BSSs and hardware / software for providing overlapping network allocation vectors (ONAV) in addition to a network allocation vector (NAV), the ONAV included to facilitate the effectiveness of the RTS / CTS during CFPs.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a wireless medium access control (MAC) protocol, and more particularly relates to a hybrid wireless MAC protocol which uses a Ready To Send(RTS) / Clear To Send(CTS) exchange during a contention free period (CFP) in order to avoid contention from Stations (STAs) in overlapping basic service sets (BSSs). [0003] 2. Description of Related Art [0004] The wireless communication market has lately enjoyed tremendous growth and is now capable of reaching every place on earth. Hundreds of millions of people exchange information every day using pagers, cellular telephones and other wireless communication products. Wireless communication has broken the harnesses of wireline networks, allowing users to access and share information on a global scale nearly everywhere they venture. [0005] Standard LAN protocols (wireline), such as ETHERNET™, operate on wireline networks using various MAC protocols, ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): H04L12/56H04L12/28
CPCH04W74/0816H04W88/10H04W84/12H04W80/02
Inventor CERVELLO, GERARDCHOI, SUNGHYUN
Owner CERVELLO GERARD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products