Wiener-Hammerstein Channel Model Identification Method
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Solution Overview
Problem
Existing telecommunications systems face challenges in accurately modeling non-linear channels with amplifiers near saturation, leading to signal distortion, which is difficult to correct due to high computational complexity and memory requirements of existing models like the Volterra series.
Innovation Solution
A method is proposed to model telecommunication channels using a series of linear and non-linear functions, where pilot sequences are sent to determine the parameters of the channel, specifically using wideband and band-limited sequences to differentiate between linear and non-linear effects, allowing for accurate identification of the Wiener-Hammerstein model without approximations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Volterra series model is used to identify the channel, then the channel can be modeled, but the computational complexity and memory requirements become very high
Solution Approach 1:
The patent segments the channel identification process into two distinct phases: a training phase using large pilot sequences to capture channel characteristics, and an operational phase using compressed representations. The channel impulse response is divided into overlapping segments that are processed separately, reducing the computational burden while maintaining identification accuracy.
Solution Approach 2:
The patent changes the parameter representation of the channel model by using a compressed form of the channel impulse response with reduced memory requirements. Instead of storing and processing the full high-dimensional Volterra series coefficients, the system uses a compressed parameter set that captures essential channel characteristics with lower computational complexity.
2Measurement precision
If a large pilot sequence is used to identify the channel accurately, then the channel identification accuracy improves, but the memory and computational complexity increase
Solution Approach 1:
The patent extracts the essential channel characteristics from a large pilot sequence during a training phase, then uses only the extracted compressed representation during operational phases. This extraction process separates the essential information needed for channel identification from the redundant data, allowing accurate channel modeling without requiring large pilot sequences in every transmission.
Solution Approach 2:
The patent performs preliminary channel identification using a large pilot sequence in a training phase before actual data transmission. This preliminary action captures the channel characteristics upfront, allowing subsequent communications to use the pre-compressed channel model without requiring repeated large pilot sequences, thus reducing overall memory and computational requirements.
3Use of energy by moving object
If amplifiers work near saturation to optimize efficiency, then energy efficiency improves, but non-linear distortion increases
Solution Approach 1:
The patent applies preliminary anti-action by using predistortion techniques where the transmitter pre-compensates for the expected non-linear distortion caused by saturation-mode amplifiers. The channel model identified through the two-phase process enables the system to calculate and apply appropriate predistortion, counteracting the harmful non-linear effects before they occur and allowing amplifiers to operate efficiently near saturation.
Data Source
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AI summary
The invention relates to a method to parameter a model of a telecommunication channel, said communication channel comprising an emitter, a receiver, and at least one amplifier amplifying a signal sent by the emitter to the receiver; said model comprising a series of at least one linear filter, and a non-linear function; said method comprising: sending to the receiver, by the emitter, a first pilot sequence x1 , said first pilot sequence being a wideband sequence; sending to the receiver, by the emitter, a second pilot sequence x2, said second pilot sequence being a band-limited sequence in a band of said at least one linear filter, parameters of said band being determined from a first received sequence w1, corresponding to the first pilot sequence x1, sent by the emitter, and said second pilot sequence having an amplitude higher than an amplitude of the first pilot sequence.