Iterative Interference Cancellation for More Addressable Interferers

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Solution Overview

Problem

Wireless communication receivers face limitations in interference mitigation due to the unavailability of control information from interfering cells, especially for devices near the edge of a cell or those receiving weak control channel signals, which restricts the application of efficient interference mitigation techniques.

Innovation Solution

An iterative receiver process is implemented where improved a priori information from previous iterations is used to detect additional control messages, expanding the set of addressable interferers and enhancing interference mitigation by re-attempting control message detection and adjusting interference mitigation techniques based on derived signal characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If interference mitigation techniques are applied using initial control message decoding, then interference suppression is improved, but the set of addressable interferers is limited due to decoding failures at cell edges

Engineering Contradiction:
Improveinterference suppressionVSAvoidset of addressable interferers
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by performing initial control message decoding before interference mitigation, but recognizes this limitation prevents addressing interferers at cell edges. The iterative approach then performs additional decoding attempts using updated signal estimates, effectively performing the action of expanding the addressable interferer set after the preliminary step has been completed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the results of initial interference mitigation to improve subsequent control message decoding attempts. The signal estimates from the first iteration are fed back into the decoding process, allowing the receiver to successfully decode control messages from additional interferers that were initially undecodable, thereby expanding the set of addressable interferers.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If iterative receiver process is used to detect additional control messages, then the set of addressable interferers is expanded, but receiver complexity increases

Engineering Contradiction:
Improveset of addressable interferersVSAvoidreceiver complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by implementing an iterative receiver process that dynamically adjusts the set of addressable interferers based on decoding success. Rather than using a fixed set determined by initial decoding, the system iteratively refines the signal estimates and attempts to decode additional control messages, allowing the receiver configuration to adapt and expand as the process progresses.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements continuity of useful action by maintaining the iterative receiver process that continuously attempts to decode control messages from additional interferers. Instead of performing a single decoding attempt and stopping, the system continues to refine estimates and attempt decoding across multiple iterations, keeping the useful action of interference mitigation continuous and improving throughout the process.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentUS8938038B2Extending the set of addressable interferers for interference mitigation
Publication Date: 2015.01.20 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US8938038B2 patent drawing
  • US8938038B2 patent drawing
  • US8938038B2 patent drawing

AI summary

Techniques for expanding the set of addressable interfering signals in an interference cancelling receiver are described, where the task of control message detection from interfering cells is integrated in an iterative receiver process where increasingly better a priori information on the received data signals from the previous iteration is used to detect additional control messages and successively grow the set of interfering signals included in the receiver's interference mitigation processing. In an example method, first estimated symbols for a desired signal are generated. A control channel corresponding to a first interfering signal is detected, where said detecting is based on the first estimated symbols. Signal characteristics information for the first interfering signal is then derived from the detected control channel signal, and used to generate second estimated symbols for the desired signal, using an interference-mitigation technique to mitigate the effects of the interfering signal.