Downlink Message Scrambling for Implicit Terminal Identification

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Solution Overview

Problem

In ultra-narrow band wireless communication systems, the existing methods for transmitting downlink messages are inefficient due to high duration and spectral width, especially when using half-duplex base stations, which limits data exchange and increases complexity in the access network.

Innovation Solution

A method that generates and transmits downlink messages by modifying main data and error detection data using a reversible function based on a temporary identifier of the addressee terminal, determined from control data in uplink messages, without increasing spectral width or duration, allowing terminals to process and identify intended messages efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If downlink messages include explicit terminal identifiers, then message routing accuracy is improved, but message duration and spectral width increase

Engineering Contradiction:

Improvemessage routing accuracyVSAvoidmessage duration

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent extracts the terminal identifier from the downlink message content and uses it as a scrambling code for the entire message. This removes the need to transmit the identifier explicitly while still enabling the receiving terminal to identify and decode its intended message through the scrambling mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the representation of the terminal identifier from a direct data field to a scrambling parameter. The identifier is transformed into a scrambling code that modifies the message bits, thereby embedding identification functionality within the message structure itself rather than as a separate element.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If downlink messages include explicit terminal identifiers, then message routing accuracy is improved, but spectral width increases

Engineering Contradiction:

Improvemessage routing accuracyVSAvoidspectral width

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the terminal identifier with the message data by using the identifier as a scrambling code that operates on the entire message. This combines the identification function and data transmission function into a single integrated process, eliminating the need for separate identifier fields.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If base stations store identifiers for all terminals, then downlink message delivery accuracy is improved, but access network complexity increases

Engineering Contradiction:

Improvedownlink message delivery accuracyVSAvoidaccess network complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables terminals to self-identify as the intended recipients of downlink messages through autonomous scrambling operations. Each terminal uses its own identifier to scramble the message and, upon receiving a scrambled message, uses its identifier to attempt unscrambling. This self-service mechanism eliminates the need for base stations to maintain and manage terminal identifier databases.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent inverts the traditional approach where the base station actively routes messages to terminals. Instead, terminals actively identify their own messages by attempting to unscramble received messages with their identifiers. This role reversal shifts the identification burden from the base station to the terminals.

Inventive Principle:

Principle #13The other way round (Inversion)

4Adaptability or versatility

If half-duplex base stations transmit downlink messages, then data exchange capability is improved, but uplink reception time is reduced

Engineering Contradiction:

Improvedata exchange capabilityVSAvoiduplink reception time

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of moving object

Solution Approach 1:

The patent implements periodic time-division multiplexing where base stations alternate between transmission and reception modes in regular cycles. During transmission periods, base stations send downlink messages to terminals; during reception periods, they listen for uplink messages from terminals. This periodic switching enables half-duplex operation while maintaining both data exchange capability and uplink reception functionality.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10314027B2Method for transmitting and receiving downlink messages with implicit identification of recipients

Publication Date: 2019.06.04 UNABIZ SAS

AI summary

A method for transmitting a downlink message on a downlink between an access network and a plurality of terminals. The downlink message includes main data to be transmitted to a receiving terminal. Error detection data is generated from the main data. Main data and/or error-detection data are modified on the basis of an identifier of the receiving terminal, using a predefined reversible modification function. The modification is performed at a constant spectral width and for a constant duration with respect to the aforementioned main data and/or error-detection data. A downlink message including the main data and the error-detection data obtained after modification are transmitted. Also, a method for receiving the downlink messages.