Dynamic Receiver Filter Switching for Interference Mitigation

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Solution Overview

Problem

In wireless communication networks, using multiple carriers for downlink communication increases susceptibility to interference due to the need for wider receiver filters, which can lead to reduced quality and throughput, and potentially result in lost connections, especially when severe interference occurs.

Innovation Solution

Implementing a mode switching scheme that temporarily switches between multi-carrier and single-carrier modes, using a narrower filter configuration during single-carrier intervals to maintain connection and receive critical messages and control signaling, thereby reducing interference sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a wide receiver filter is used to receive multiple frequency carriers simultaneously, then the data throughput is increased, but the receiver becomes more sensitive to interference from other transmissions

Engineering Contradiction:

Improvedata throughputVSAvoidinterference sensitivity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The receiver filter bandwidth is made dynamic by switching between wide bandwidth mode (for receiving multiple carriers) and narrow bandwidth mode (for rejecting interference). The system adapts the filter characteristics based on whether data transmission or interference rejection is the priority at any given moment.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The receiver periodically switches between wide and narrow filter modes in a time-division manner. During wide filter periods, multiple carriers are received for high throughput; during narrow filter periods, interference is rejected. This periodic switching allows the system to achieve both high data rates and interference immunity.

Inventive Principle:

Principle #19Periodic action

2Area of stationary object

If a wide receiver filter is used to receive multiple frequency carriers, then the filter bandwidth is increased, but the suppression of frequencies outside the nominal bandwidth is reduced

Engineering Contradiction:

Improvefilter bandwidthVSAvoidout-of-band interference

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The filter bandwidth is dynamically adjusted between wide and narrow configurations. When wide bandwidth is needed to capture multiple carriers, the system accepts reduced out-of-band suppression but compensates by switching to narrow bandwidth mode periodically to reject interference that passes through.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The receiver alternates between wide filter mode (capturing multiple carriers with reduced out-of-band rejection) and narrow filter mode (strongly suppressing out-of-band frequencies). This periodic action ensures that even though out-of-band suppression is reduced during wide filter operation, the overall system maintains interference immunity through the narrow filter periods.

Inventive Principle:

Principle #19Periodic action

3Object-affected harmful factors

If separate receiver equipment is used for each carrier, then the interference rejection is improved, but the cost and space requirements become intolerable

Engineering Contradiction:

Improveinterference rejectionVSAvoidreceiver equipment quantity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A single receiver equipment is designed to perform multiple functions by dynamically changing its filter bandwidth. The same receiver handles both wide bandwidth reception (for multiple carriers) and narrow bandwidth interference rejection, eliminating the need for separate receiver equipment for each carrier while maintaining interference immunity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The receiver's filter bandwidth parameter is changed dynamically between wide and narrow values. This parameter change allows a single receiver to achieve the interference rejection performance that would otherwise require multiple separate receivers, while keeping the physical equipment count low and costs acceptable.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10721790B2Methods and nodes for maintaining a wireless connection in a wireless communications network

Publication Date: 2020.07.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method and user node for maintaining a connection with a network node when operating in a multi-carrier mode using a first filter configuration to receive multiple frequency carriers simultaneously for downlink communication. The user node applies a mode switching scheme comprising first intervals for the multi-carrier mode and second intervals for a single carrier mode using a second filter configuration to receive a single carrier for the downlink communication. In this case, the user node switches temporarily from the multi-carrier mode to operate in the single carrier mode during the second intervals according to the mode switching scheme. Thereby the user node is enabled to maintain the connection by receiving messages and/or control signalling from the network node over the single frequency carrier during the second intervals, for example when the multi-carrier mode is highly disturbed by interference.