Access Point Spatial Weighting for Downlink Throughput

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Solution Overview

Problem

Existing wireless communication systems, particularly those adhering to the IEEE 802.11 standard, face challenges in achieving high downlink throughput due to differences in radio conditions between transmitters and receivers, and the interference caused by multiple acknowledgement bursts from mobile stations, which complicates accurate channel estimation and data transmission.

Innovation Solution

The implementation of a method using an access point with multiple antennas to weight and transmit data selectively to each mobile station, ensuring each station receives only its intended data, thereby increasing downlink throughput without modifying existing IEEE 802.11 compliant mobile stations and reducing acknowledgement burst overlap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple mobile stations transmit acknowledgement bursts simultaneously, then the system maintains simple operation, but the acknowledgement bursts interfere with each other causing loss of information and reduced reliability

Engineering Contradiction:

Improveoperation simplicityVSAvoidacknowledgement burst interference

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The patent segments the downlink transmission by applying different spatial weights to different mobile stations across multiple antennas. Each mobile station receives a segmented portion of the transmitted signal tailored to its specific channel characteristics, preventing acknowledgement burst interference while maintaining operational simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by customizing the transmission weights for each mobile station based on its specific radio conditions and channel state. Each mobile station experiences optimized local signal quality through station-specific weighting, eliminating acknowledgement interference without complicating overall system operation

Inventive Principle:

Principle #3Local quality

2Productivity

If the system transmits data to multiple mobile stations simultaneously using the same frequency, then the productivity increases, but the channel estimation accuracy deteriorates due to radio condition differences

Engineering Contradiction:

Improvedownlink throughputVSAvoidchannel estimation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary channel estimation and weight calculation for each mobile station before simultaneous data transmission. The access point pre-computes optimal spatial weights based on current channel conditions, enabling accurate multi-user transmission without compromising channel estimation precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent dynamically changes transmission parameters (spatial weights, beamforming vectors) for each mobile station based on real-time radio conditions. By adapting these parameters per user, the system achieves high productivity through simultaneous transmission while maintaining accurate channel estimation for each user's specific conditions

Inventive Principle:

Principle #35Parameter changes

3Speed

If sophisticated beam-forming techniques are implemented, then the data rate increases, but the device complexity increases making implementation difficult

Engineering Contradiction:

Improvedata rateVSAvoidimplementation complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent implements partial beam-forming by applying spatial weighting only to the downlink transmission from the access point, while leaving mobile station receivers relatively simple. This partial application of sophisticated techniques achieves high data rates without requiring complex implementation at all devices

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses the access point as an intermediary that performs the complex beam-forming calculations and weight adjustments. The access point mediates between multiple mobile stations with different channel conditions, applying sophisticated techniques centrally while keeping individual mobile station implementations simple

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7512096B2Communicating data between an access point and multiple wireless devices over a link

Publication Date: 2009.03.31 WSOU INVESTMENTS LLC

AI summary

The present invention provides a method and an apparatus for communicating data over a network between a communication node, for example, an access point having a first and a second antenna and a first and a second mobile station. The method comprises weighting a first data at the access point to transmit the first data using the first and second antennas so that the first mobile station only receives the first data and weighting a second data at the access point to transmit the second data using the first and second antennas so that the second mobile station only receives the second data. A space division multiple access (SDMA) module may cause a transmission protocol to transmit the first data to the first mobile station on the downlink and transmit the second data to the second mobile station in parallel to the transmission of the first data on the downlink. In a telecommunication system, this substantially simultaneous transmission of the first and second data using a similar carrier frequency in a radio frequency communication over a wireless local area network (WLAN) may increase throughput of a downlink, for example, by a factor nominally equal to the number of antennas at an access point.