LTE Relay Node Subframe Segmentation for Inband Interference

Solution Overview

Problem

In LTE-Advanced mobile communication systems, simultaneous transmission and reception processes in Un and Uu subframes by relay nodes can cause interference to the relay node's reception circuit.

Innovation Solution

The method involves the radio base station transmitting a first downlink signal in a first subframe to a relay node, with the relay node notifying the base station to prevent subframe overlap, and the base station adjusting the transmission timing, number of OFDM symbols, and arrangement pattern of reference signals for the relay node to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the relay node performs simultaneous reception in Un subframe and transmission in Uu subframe, then communication efficiency is improved, but interference occurs to the relay node's reception circuit

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidinterference to reception circuit

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the subframe structure by introducing a guard period and dividing the subframe into distinct transmission and reception regions. This segmentation prevents simultaneous transmission and reception in the same time-frequency resources, thereby eliminating self-interference while maintaining communication efficiency through proper resource allocation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by configuring the guard period in advance before the actual transmission/reception operations. The guard period is pre-allocated in the subframe structure to ensure that transmission and reception operations do not overlap, preventing interference before it can occur.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the relay node performs simultaneous transmission in Un subframe and reception in Uu subframe, then communication efficiency is improved, but interference occurs to the relay node's reception circuit

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidinterference to reception circuit

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the subframe structure by introducing a guard period and dividing the subframe into distinct transmission and reception regions. This segmentation prevents simultaneous transmission and reception in the same time-frequency resources, thereby eliminating self-interference while maintaining communication efficiency through proper resource allocation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by configuring the guard period in advance before the actual transmission/reception operations. The guard period is pre-allocated in the subframe structure to ensure that transmission and reception operations do not overlap, preventing interference before it can occur.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If subframes are allowed to overlap in time direction, then resource utilization is improved, but interference occurs to the relay node

Engineering Contradiction:

Improveresource utilizationVSAvoidinterference to relay node

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the subframe configuration adaptable through the guard period mechanism. The system dynamically adjusts the timing relationships between Un and Uu subframes using the guard period, allowing flexible resource allocation while preventing harmful overlaps that would cause interference to the relay node.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9832768B2Mobile communication method and radio base station

Publication Date: 2017.11.28 NTT DOCOMO INC

AI summary

A mobile communication method according to the present invention includes a step of transmitting, by a radio base station DeNB, a first downlink signal in a first subframe to a relay node RN, a step of transmitting, by the relay node RN, a second downlink signal in a second subframe to a mobile station UE, a step of notifying, by the relay node RN, the radio base station DeNB of information indicating “Half duplex inband Relay Node”, and a step of transmitting, by the radio base station DeNB, a transmission timing of R-PDCCH and R-PDSCH in a Un subframe to the relay node RN according to the notification.