Downlink Signaling Randomization Against Spoofing and Eavesdropping

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Solution Overview

Problem

Wireless communications systems face challenges in securing downlink signaling against spoofers and eavesdroppers, particularly in tactical networks where critical information is vulnerable to interference and unauthorized access.

Innovation Solution

Implementing a pseudo-random function (PRF) to pseudo-randomize synchronization signal blocks (SSBs) and control channels using UE-specific or UE-common keys, timing information, and physical cell identifiers to enhance security by randomizing timing, frequency, and sequence information, and configuring initial control resource sets to be offset from SSBs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If downlink signaling is transmitted using fixed timing and frequency resources, then ease of operation is improved, but security deteriorates due to vulnerability to spoofing and eavesdropping

Engineering Contradiction:

Improveease of receiving downlink signalingVSAvoidsecurity against spoofing and eavesdropping

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from fixed timing and frequency resources to dynamic, pseudo-randomly determined resources. The PRF generates varying time-frequency positions for SSBs and control channels based on input parameters, making the signaling locations change over time rather than remaining static, thereby enhancing security while maintaining operational feasibility

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of downlink signaling by using a pseudo-random function to determine time-frequency resources instead of fixed allocations. The PRF transforms input parameters (frame number, cell ID, etc.) into variable output parameters (time offsets, frequency positions), creating unpredictable signaling locations that resist spoofing and eavesdropping while allowing legitimate devices to access through parameter matching

Inventive Principle:

Principle #35Parameter changes

2Reliability

If pseudo-random functions are used to randomize SSB and control channel resources, then security is improved, but device complexity increases

Engineering Contradiction:

Improvesecurity against spoofing and eavesdroppingVSAvoidcomplexity of PRF implementation

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling user equipment to autonomously compute the pseudo-random sequence using the PRF with inputs derived from publicly available information (frame number, cell ID, SSB index). The UE independently generates the same time-frequency resource positions as the network without requiring additional signaling or complex external coordination, thereby enhancing security while limiting complexity growth to manageable levels

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent applies universality by designing the PRF to serve multiple functions simultaneously: it determines time offsets for SSB bursts, frequency positions for control channels, and resource allocations for data channels. This multi-functional approach consolidates what could be separate complex mechanisms into a single versatile function, improving security while controlling overall system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If timing and frequency information for SSBs is pseudo-randomized, then security is improved, but measurement precision deteriorates due to unpredictable resource positions

Engineering Contradiction:

Improvesecurity of downlink signalingVSAvoidprecision of timing and frequency measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by providing reference information in advance through the PRF relationship. While the exact SSB positions are pseudo-random, the UE can pre-compute expected positions based on known parameters (frame number, cell ID, SSB index) fed into the PRF. This preliminary computation enables precise measurement and synchronization despite the pseudo-random nature of the actual positions, resolving the contradiction between security and measurement precision

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12587881B2Security for downlink signaling

Publication Date: 2026.03.24 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may monitor a set of resources for one or more synchronization signal blocks (SSBs) associated with one or more pseudo-random sequences. The one or more pseudo-random sequences and the set of resources may be indicated by an output of a pseudo-random function (PRF) that is based on a timing parameter, a cell identifier, and a key. In some examples, the UE may monitor a set of resources within a control resource set for a downlink control channel, where the set of resources for the downlink control channel is based on an output of the PRF. The UE communicate with a network entity via a cell associated with the cell identifier based on the monitoring.