Duplex Communication Network Using Reciprocal Channel Estimation
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Solution Overview
Problem
Conventional communication networks require training sequences to be sent and evaluated in both directions, reducing the effective payload data rate and being susceptible to uneven channel disturbances, with performance determined by the weaker channel.
Innovation Solution
A communication network design that transmits a priori known sequences and data simultaneously in one direction while receiving in another, allowing channel estimates to be determined on the other side, enabling reciprocity-based channel estimation and predistortion to enhance transmission quality and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If training sequences are transmitted in both directions to determine channel properties, then channel estimation accuracy is improved, but the effective payload data rate deteriorates due to reduced transmission time
Solution Approach 1:
The patent merges the channel estimation function into one direction only by exploiting channel reciprocity. The base station transmits training sequences in the downlink, and both the base station and user equipment use these same sequences for channel estimation in their respective directions, eliminating the need for separate uplink training sequences.
Solution Approach 2:
The downlink training sequences serve multiple functions: they enable downlink channel estimation at the user equipment, enable uplink channel estimation at the base station through reciprocity, and provide a reference for both transmission directions simultaneously, replacing what would traditionally require separate training sequences in each direction.
2Device complexity
If frequency bands are statically assigned to transmission directions, then frequency band management is simplified, but transmission quality deteriorates when one frequency band is more disturbed than the other
Solution Approach 1:
The patent introduces dynamic frequency band assignment where the base station switches between first and second frequency bands for downlink transmission based on channel conditions. This allows the system to adapt to varying channel quality in different frequency bands, ensuring that the less disturbed band is used when available, thereby improving overall transmission reliability.
3Measurement precision
If a priori known sequences are transmitted in both directions, then channel estimation can be performed on both sides, but signaling overhead increases and energy efficiency deteriorates
Solution Approach 1:
The patent combines the channel estimation functionality for both transmission directions into a single downlink training sequence transmission. The base station transmits the sequence once in the downlink, and both the base station (for uplink estimation) and user equipment (for downlink estimation) derive channel information from this single transmission.
Solution Approach 2:
The system exploits the natural reciprocity of the radio channel to automatically provide channel estimation information for the uplink direction without requiring additional signaling. The base station uses the received downlink training sequences to estimate the uplink channel characteristics, eliminating the need for separate uplink training transmissions.
Data Source
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AI summary
A method for operating a first communication module (C1) is provided, comprising: transmitting a first a priori known sequence (S11) and first data (N12) on a first duplex channel (CH1) within a first timeframe (tf1), receiving second data (N12) on a second duplex channel (CH2) within the first timeframe (tf1), wherein the reception of the second data (N12) is performed simultaneously with the transmission of the first a priori known sequence (S11) and/or the first data (N11), receiving third data (N21) on the first duplex channel (CH1) within a second timeframe (tf2) following the first timeframe (tf1), and transmitting a second a priori known sequence (S21) and fourth data (N22) on the second duplex channel (CH2) within the second timeframe (tf2).wherein the transmission of the second a priori known sequence (S21) and/or the fourth data (N22) is carried out simultaneously with the reception of the third data (N21).