IAB Node Timing Alignment for 5G NR Networks

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Solution Overview

Problem

In integrated access and backhaul (IAB) radio communication systems, there is a need for a mechanism to appropriately determine the uplink transmission timing for IAB nodes that support multiple alignment methods, ensuring proper timing alignment between parent and child nodes in 5G New Radio (NR) networks.

Innovation Solution

A radio communication node with a control unit that determines downlink transmission timing based on an upper node's timing and specifies uplink transmission timing using methods such as Case #1, Case #6, and Case #7, utilizing propagation delays and timing advances to align transmission and reception timings across the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple alignment methods (Case #1, Case #6, Case #7) are supported for determining MT transmission timing, then the adaptability and flexibility of the IAB node are improved, but the device complexity and difficulty of determining the appropriate timing method increase

Engineering Contradiction:

Improvesupport for multiple alignment methodsVSAvoidcomplexity of timing determination mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic selection of timing alignment methods by enabling the IAB node to switch between different alignment cases (Case #1, Case #6, Case #7) based on real-time network conditions and configuration. The control unit dynamically determines which alignment method to apply by evaluating propagation delays, timing advance values, and network requirements, allowing the system to adapt its timing mechanism rather than being fixed to a single method.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters used for timing determination by allowing the IAB node to use different combinations of parameters depending on the selected alignment case. For example, Case #1 uses propagation delay (Tpropagation_0) calculated from TA/2+T_delta, while Case #6 and Case #7 combine this with UL transmission timing alignment or UL reception timing alignment. The system selectively applies different parameter sets based on the chosen alignment method.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If propagation delay calculation (TA/2+T_delta) is used to align DL transmission timing, then the timing alignment precision between parent and child nodes is improved, but the loss of time for timing calculation and adjustment increases

Engineering Contradiction:

Improvetiming alignment precisionVSAvoidtime for timing calculation and adjustment

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating the propagation delay (Tpropagation) using the formula TA/2+T_delta before actual transmission timing alignment is needed. The IAB node performs this calculation in advance based on the Timing Advance (TA) value received from the parent node and the switching time parameter T_delta, so that when transmission timing alignment is required, the value is already ready for immediate application without additional calculation delays.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240215021A1Radio communication node

Publication Date: 2024.06.27 NTT DOCOMO INC

AI summary

A radio communication node includes: a control unit that determines a downlink transmission timing in the radio communication node based on a downlink transmission timing in an upper node; and a transmission/reception unit that performs transmission and reception at the determined timing, wherein the control unit determines an uplink transmission timing in the radio communication node based on a specifying method.