Interference Aware Packet Transmission for OBSS

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Solution Overview

Problem

In communications networks, overlapping basic service sets (OBSSs) cause interference due to the lack of sufficient channel estimation mechanisms for radio transceiver devices with multiple antennas, especially during non-multi-stream transmissions, leading to performance losses.

Innovation Solution

A radio transceiver device equipped with processing circuitry that estimates interference and determines the number of symbols for channel estimation in packets to be transmitted, allowing other devices to estimate the channel and reduce interference by adjusting beamforming weights and transmission power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If channel estimation is performed using available LTF symbols in non-multi-stream transmissions, then interference reduction is attempted, but the channel estimation is insufficient for multiple antennas leading to performance loss

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidtransmission structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The packet structure is segmented to include dedicated LTF symbols specifically for channel estimation purposes. The transmission is divided into distinct segments: LTF symbols for channel estimation, data symbols for information transfer, and the segmentation allows receivers to properly estimate channels for multiple antennas even in non-multi-stream transmissions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

LTF symbols are placed at the beginning of the packet transmission to perform channel estimation before data transmission. This preliminary action allows receivers to obtain accurate channel state information upfront, which is then used for subsequent data reception and interference mitigation through beamforming

Inventive Principle:

Principle #10Preliminary action

2Productivity

If beamforming is used to improve transmission efficiency, then the gain from beamforming is improved, but high overhead is introduced through the sounding procedure

Engineering Contradiction:

Improvebeamforming transmission efficiencyVSAvoidsounding procedure overhead

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

Instead of performing complete Null Data Packet (NDP) sounding procedures which require separate announcement frames and feedback exchanges, the invention uses partial channel estimation information embedded directly in the data packets. This partial action approach provides sufficient channel state information for beamforming without the full overhead of traditional sounding procedures

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The channel estimation function is merged with the data transmission process. LTF symbols that would traditionally be part of a separate sounding procedure are combined with and embedded within the data packet structure, allowing channel estimation and data transmission to occur simultaneously rather than as separate overhead operations

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If orthogonal channels are assigned to neighboring BSSs to avoid interference, then interference is reduced, but channel availability is limited in dense deployments

Engineering Contradiction:

Improveinterference between BSSsVSAvoidchannel reuse capability

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The invention converts the harmful effect of co-channel interference into a beneficial feature by using the interference information for channel estimation. Receivers estimate the channel including interference components, then use this information to compute beamforming weights that null or suppress the interfering signals, effectively turning the presence of interference into an opportunity for adaptive beamforming

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The beamforming weights are dynamically adjusted based on real-time channel estimation from embedded LTF symbols. This dynamic adaptation allows the system to respond to changing interference conditions in dense deployments, continuously optimizing transmission directions to mitigate interference from neighboring BSSs that reuse the same channels

Inventive Principle:

Principle #15Dynamics

4Productivity

If served terminal devices compete for channel access in OBSS, then channel utilization is improved, but co-channel interference and performance loss increase

Engineering Contradiction:

Improvechannel access efficiencyVSAvoidcommunication performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system implements feedback mechanisms where terminal devices send acknowledgments and channel state information back to access points using the embedded LTF symbols for accurate channel estimation. This feedback loop enables access points to adjust their transmissions and beamforming strategies based on actual channel conditions and interference levels experienced by terminal devices

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11848694B2Interference aware packet transmission

Publication Date: 2023.12.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is provided mechanisms for interference aware packet transmission. A method is performed by a radio transceiver device. The method comprises obtaining an estimate of interference in a surrounding of the radio transceiver device. The method comprises determining how many symbols for channel estimation to include in a packet to be transmitted based on amount of estimated interference. The method comprises transmitting the packet towards another radio transceiver device, where the packet comprises the determined amount of symbols for channel estimation.