Joint FDCS Signaling for OFDM Links in High-Doppler Channels

Solution Overview

Problem

Existing OFDM-based systems face challenges with frequency offsets and high Doppler channels, leading to performance degradation and spectral efficiency loss due to the need for advanced receivers and the inclusion of frequency domain cyclic sequences.

Innovation Solution

Implementing a frequency domain cyclic sequence (FDCS) for communication between nodes, using control signaling to indicate its use, and employing a joint FDCS for multiple nodes to reduce the number of subcarriers required, thereby improving spectral efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a frequency domain cyclic sequence (FDCS) is used to protect against frequency offsets and high Doppler channels, then signal protection against FOs and high Doppler channels is improved, but spectral efficiency deteriorates due to subcarrier allocation loss

Engineering Contradiction:

Improvesignal protection against frequency offsets and high Doppler channelsVSAvoidspectral efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the FDCS functionality across multiple users by implementing a joint FDCS that serves multiple second nodes simultaneously. Instead of allocating separate FDCS resources to each user, the system combines the cyclic sequence generation and applies a single joint FDCS structure, thereby reducing the total number of subcarriers consumed while maintaining protection against frequency offsets and high Doppler effects for all users.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If an advanced receiver is used at the base station to cope with frequency offsets and high Doppler channels, then performance degradation is reduced, but device complexity increases

Engineering Contradiction:

Improveperformance in high Doppler channelsVSAvoidreceiver complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-compensating for frequency offsets and Doppler effects through the FDCS structure before transmission. The cyclic sequence is designed to inherently counteract these channel impairments, so that the receiver does not need complex processing algorithms. The protection is built into the signal structure itself, simplifying the receiver design while maintaining robustness against frequency offsets and high Doppler channels.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If separate FDCS is used for each second node, then individual signal protection is ensured, but resource usage increases reducing overall spectral efficiency

Engineering Contradiction:

Improveindividual signal protectionVSAvoidnumber of subcarriers used

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges the FDCS functionality across multiple users by implementing a joint FDCS that serves multiple second nodes simultaneously. Instead of allocating separate FDCS resources to each user, the system combines the cyclic sequence generation and applies a single joint FDCS structure, thereby reducing the total number of subcarriers consumed while maintaining protection against frequency offsets and high Doppler effects for all users.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The joint FDCS structure serves multiple functions simultaneously: it provides cyclic prefix protection for multiple users, enables frequency offset compensation, and supports high Doppler channel robustness all within a single unified structure. This multi-functionality eliminates the need for separate FDCS instances for each user, optimizing resource utilization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250365718A1Methods for communication with a plurality of second nodes via respective channels, related first nodes and related second nodes

Publication Date: 2025.11.27 SONY GROUP CORP

AI summary

Disclosed is a method, performed by a first node, for communication with a plurality of second nodes via respective channels. The method comprises transmitting, to at least two second nodes of the plurality of second nodes, control signalling indicating that a frequency domain cyclic sequence associated with one or more data sets is used for the communication between the first node and one or both of the at least two second nodes.