Wireless Device Training Signal Allocation for Throughput

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Solution Overview

Problem

In wireless communication systems with a large number of transmit antennas, the overhead for channel estimation and feedback signals increases, leading to reduced system throughput due to the need for a large number of OFDM symbols and increased bit length of feedback information packets.

Innovation Solution

The proposed solution involves allocating frequency channels to each transmission port such that iterative coefficients are set to share training signals across multiple transmission ports, reducing the number of OFDM symbols required for channel estimation and optimizing the allocation of subcarriers, thereby reducing overhead and improving transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a large number of transmit antennas are used for MIMO communication, then the throughput is increased, but the overhead for channel estimation and feedback signals is increased

Engineering Contradiction:
ImprovethroughputVSAvoidoverhead for channel estimation and feedback signals
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent combines channel estimation for multiple transmit antennas into a single training signal transmission. By using a composite training signal that contains information for estimating channels of multiple antennas simultaneously, the system reduces the number of separate training signals needed, thereby reducing overhead while maintaining the ability to support multiple transmit antennas for high throughput

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The training signal is designed to serve multiple functions: it enables channel estimation for multiple transmit antennas simultaneously and carries information that can be used for both channel estimation and beamforming optimization. This multi-functional approach reduces the total amount of training signals required in the system

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If the number of OFDM symbols for channel estimation is increased, then the channel information accuracy is improved, but the system throughput is reduced

Engineering Contradiction:
Improvechannel information accuracyVSAvoidsystem throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent changes the structure and composition of the training signal to improve channel estimation accuracy without increasing the number of OFDM symbols. By optimizing the training signal's frequency domain representation and using intelligent allocation of training resources across different antennas, the system achieves better estimation precision within the same time budget

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from time-domain multiplication (using more OFDM symbols) to frequency-domain optimization (using composite training signals with specific frequency allocations). By operating in the frequency domain and using Fourier transform relationships, the system achieves accurate channel estimation for multiple antennas without requiring additional time symbols

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If training signals are transmitted for each transmit antenna, then the channel information is accurately acquired, but the number of OFDM symbols is increased

Engineering Contradiction:
Improvechannel information accuracyVSAvoidnumber of OFDM symbols
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the training signals for multiple transmit antennas into a single composite training signal. This composite signal contains embedded information that allows the receiver to estimate channels for multiple antennas simultaneously, thereby reducing the number of OFDM symbols required while maintaining accurate channel information acquisition

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2790338B1Wireless device and training signal transmission method
Publication Date: 2019.09.18 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP2790338B1 patent drawingFigure 1
  • EP2790338B1 patent drawingFigure 2A~2B
  • EP2790338B1 patent drawingFigure 3

AI summary

The number of OFDM symbols for channel estimation is reduced, overhead due to a pilot signal and a feedback signal is reduced, and the throughput is improved. A wireless apparatus is provided with: an iterative coefficient setting unit which sets, for a plurality of transmission ports, an iterative coefficient representing the number of transmission ports which share a plurality of frequency channels of training signals for estimating the channel information; a training signal generating unit which allocates frequency channels to each transmission port so as to satisfy the set iterative coefficient and generates L training signals based on the allocated frequency channels; a channel information acquiring unit which acquires channel information estimated from the training signals from a communication partner for the frequency channels allocated to each transmission port; and a channel information interpolating unit which interpolates channel information of a remaining frequency channel other than the frequency channels allocated to each transmission port from the acquired channel information.