Transmitter-Specific Pilot Precoding for SFN Channel Estimation

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Solution Overview

Problem

In broadcast communication systems, especially in Single Frequency Networks (SFN) with frequency reuse-one, existing technologies fail to provide transmitter-specific pilots for accurate channel estimation, leading to severe co-channel interference and performance degradation due to the use of common pilots across all transmitters.

Innovation Solution

The implementation of broadcast transmitter-specific pilot signals, generated using a precoding filter module that produces orthogonal or quasi-orthogonal precoding sequences based on a computed location index, allowing for accurate channel estimation and interference suppression by distinguishing between desired and interfering channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If common pilots are used across all broadcast transmitters in SFN mode, then synchronization and frequency efficiency are improved, but channel estimation accuracy deteriorates due to inability to distinguish desired channel from interfering channels

Engineering Contradiction:

Improvefrequency efficiencyVSAvoidchannel estimation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the common pilot signal into transmitter-specific components by applying different precoding sequences from a codebook at each transmitter. Each transmitter selects a unique precoding sequence based on its identifier, creating orthogonal or quasi-orthogonal pilot signals that can be distinguished at the receiver while maintaining the single-frequency network structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the pilot signal properties transmitter-specific through precoding. Each transmitter imparts unique characteristics to its pilot signal using transmitter-specific precoding sequences, allowing the receiver to locally estimate individual channel responses for each transmitter while maintaining overall system synchronization

Inventive Principle:

Principle #3Local quality

2Measurement precision

If transmitter-specific pilots are implemented in SFN mode, then channel estimation accuracy is improved, but system complexity increases due to need for precoding filter modules and codebook management

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidtransmitter structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a universal codebook of precoding sequences that can be applied across all transmitters in the SFN. The same codebook structure and selection mechanism are used by every transmitter, simplifying implementation while achieving transmitter-specific pilot signals. The receiver uses a corresponding universal codebook for channel estimation

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the parameter of pilot signal phase and amplitude distribution through precoding without altering the fundamental SFN operation. By selecting different precoding sequences from the codebook based on transmitter identifiers, the system creates distinguishable pilot signals while maintaining compatibility with existing SFN infrastructure

Inventive Principle:

Principle #35Parameter changes

3Productivity

If frequency reuse-one is used with common pilots, then spectrum efficiency is improved, but co-channel interference worsens making reliable reception impossible at transmitter intersections

Engineering Contradiction:

Improvespectrum efficiencyVSAvoidco-channel interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful co-channel interference into a beneficial situation by using the interfering transmitters' pilot signals as reference for interference estimation. The receiver uses the orthogonal precoding sequences to separately estimate desired channel and interfering channels, then uses this interference knowledge to suppress it and improve reception at transmitter intersections

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS20240097958A1System and method for providing broadcast transmitter specific pilots in synchronized broadcast networks

Publication Date: 2024.03.21 TEJAS NETWORKS LTD

AI summary

A single frequency-based broadcast communication system includes a desired broadcast transmitter and one or more adjacent interfering broadcast transmitters in communication with a receiver over a communication channel is provided. Each of the broadcast transmitters includes a waveform generator for transmitting broadcast transmitter specific pilot signals to the receiver for receiving a superimposed transmitted broadcast transmitter specific pilot signal. The desired broadcast transmitter includes a pilot insertion module and a precoding filter module. The precoding filter module is designed to generate a transmitter specific precoding sequence based on a computed location index for specific pilot signals in a time frequency domain and precode a reference pilot signal to obtain the broadcast transmitter specific pilot signal sequences.