Wireless Access Point Downlink Duration Field Collision Avoidance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In wireless communication networks, the Collision Avoidance mechanism and retransmission procedures lead to poor network performance, such as low throughput, due to contention among multiple stations for the wireless medium, which is not effectively resolved by adjusting the Contention Window parameter.

Innovation Solution

A wireless access point transmits a downlink frame with a duration field value that includes the time for the downlink frame, acknowledgement frame, a constant waiting period, and a backoff period calculated using the maximum contention window parameter, allowing stations to set or maintain their Network Allocation Vector accordingly to avoid collisions and manage medium access efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the Contention Window parameter is adjusted to resolve collisions, then communication collisions are reduced, but network throughput deteriorates due to increased transmission delays

Engineering Contradiction:

Improvecommunication collision reductionVSAvoidnetwork throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The access point sets the duration field in advance to include the backoff period, allowing stations to prepare their Network Allocation Vectors before actual transmission occurs. This preliminary setup enables collision avoidance without requiring extended transmission delays, thus maintaining throughput while reducing collisions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The access point uses the duration field as a feedback mechanism to communicate the required waiting period to stations. By incorporating the backoff period into the duration field value, the system provides stations with precise information about when they can transmit, enabling collision avoidance while maintaining efficient medium access and throughput.

Inventive Principle:

Principle #23Feedback

2Productivity

If multiple stations contend simultaneously for the wireless medium, then medium access is achieved, but communication collisions occur due to insufficient coordination

Engineering Contradiction:

Improvemedium access efficiencyVSAvoidcommunication collision avoidance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Stations set their Network Allocation Vectors in advance based on the duration field value that includes the backoff period. This preliminary action allows stations to coordinate their transmission timing before actual communication occurs, enabling simultaneous medium access without collisions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The duration field acts as an intermediary mechanism that mediates between stations' desire for simultaneous medium access and the need for collision avoidance. By incorporating the backoff period into the duration field, the system enables coordinated access while preventing collisions through centralized timing information.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7489670B2Device, system and method of uplink/downlink communication in wireless network

Publication Date: 2009.02.10 CELENO COMMUNICATIONS (ISRAEL) LTD

AI summary

Devices, systems and methods of uplink/downlink communication in wireless network. For example, a wireless access point includes a transmitter to transmit a downlink frame having a duration field value equal to or greater than a sum of: a time period corresponding to transmission of the downlink frame, a time period corresponding to transmission of an acknowledgement frame, a constant waiting period, and a backoff period calculated using a maximum contention window parameter.