Relay Node Interference Mitigation via MBSFN Timing Coordination

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Solution Overview

Problem

In LTE-Advanced mobile communication systems, simultaneous transmission and reception processes in Un and Uu radio bearers cause interference to the relay node's receiver, leading to signal interference.

Innovation Solution

A mobile communication method where the radio base station notifies the relay node of a predetermined timing for configuration changes, allowing the radio base station to schedule downlink signals at specific times, and the relay node schedules downlink signals at different times to avoid interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the relay node performs simultaneous transmission and reception processes in Un and Uu radio bearers, then communication functionality is maintained, but interference occurs to the relay node's receiver

Engineering Contradiction:

Improvecommunication functionalityVSAvoidinterference to receiver

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the transmission and reception processes in time by introducing timing adjustments. The relay node transmits downlink signals in the Un radio bearer at a predetermined timing, and receives uplink signals in the Uu radio bearer at a different timing, preventing simultaneous transmission and reception that causes interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by having the relay node transmit the timing information for downlink signals in advance. The relay node transmits timing information for downlink signals at a predetermined timing before the actual reception process, allowing the mobile station to prepare for the reception and avoid interference.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If timing coordination between Un and Uu radio bearers is implemented, then interference is reduced, but system complexity increases

Engineering Contradiction:

Improveinterference reductionVSAvoidscheduling complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements feedback mechanisms where the relay node transmits timing information for downlink signals to the mobile station. This feedback allows the mobile station to adjust its reception timing and avoid interference, while the relay node receives feedback about the actual transmission conditions to optimize future timing decisions.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9184831B2Mobile communication method, radio base station, and relay node

Publication Date: 2015.11.10 NTT DOCOMO INC

AI summary

A mobile communication method according to the present invention comprising a step A in which, when a predetermined trigger is detected, the radio base station DeNB notifies the relay node RN of a transmission timing of an MBSFN subframe by a signal for changing the configuration of an RRC connection that is set between the radio base station DeNB and the relay node RN, a step B in which the radio base station DeNB performs scheduling such that a downlink signal is transmitted to the relay node RN at the transmission timing of the MBSFN subframe, and a step C in which the relay node RN performs scheduling such that a downlink signal is transmitted at a timing other than the transmission timing of the MBSFN subframe.