5G Sidelink Synchronization Signal Anti-Jamming
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Solution Overview
Problem
Existing communication systems in 4G/LTE and 5G are vulnerable to denial by active jammers, particularly in environments where the synchronization signal block (SSB) is predictably transmitted, making it easy for jammers to disrupt sidelink networks.
Innovation Solution
The S-SSB is made unpredictable in time and frequency, forcing adversaries to significantly increase the size, weight, power, cost, complexity, and cooling power of their jammers. This is achieved by using a waveform that pseudo-randomly places the S-SSB in frequency and time within the sidelink bandwidth, and employing software-defined radios (SDRs) to manage the sidelink network and communicate the broadcast schedule.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the S-SSB is transmitted in a fixed configuration, then the UE can easily synchronize with the sync reference UE, but the fixed configuration allows active jammers to deny the sync reference signal
Solution Approach 1:
The patent applies dynamics by making the S-SSB transmission configuration variable rather than fixed. The sync reference UE dynamically changes the time and frequency positions of S-SSB transmissions according to a pseudo-random pattern, which maintains synchronization capability while preventing jamming. This resolves the contradiction by allowing easy synchronization through predictable patterns to legitimate UEs while providing denial resistance through unpredictability to jammers.
Solution Approach 2:
The patent changes the parameters of S-SSB transmission by varying time offsets and frequency positions according to a pseudo-random sequence. Instead of transmitting S-SSB at fixed intervals and frequencies, the system modifies these parameters dynamically, enabling legitimate receivers to track the changes while making it impossible for jammers to predict and block the signals effectively.
2Reliability
If the S-SSB is placed pseudo-randomly in frequency and time, then the adversary must increase the size, weight, power, cost, complexity, and cooling power of their jammer, but this increases the complexity of the communication system
Solution Approach 1:
The patent introduces an intermediary control signal that carries information about the pseudo-random pattern used for S-SSB placement. This intermediary signal enables receiving UEs to predict the S-SSB positions without requiring complex real-time tracking, thereby reducing the complexity burden while maintaining denial resistance. The intermediary provides the necessary coordination information to simplify the overall system complexity.
3Ease of operation
If a waveform is employed to announce the upcoming S-SSB, then the UE can prepare to transmit and receive the pseudo-randomly spaced S-SSB, but this requires additional signaling overhead
Solution Approach 1:
The patent merges the announcement function with existing control signaling structures in the 5G sidelink protocol. Rather than introducing a completely separate announcement mechanism, the waveform information is integrated into existing control channels and signaling procedures, thereby providing the necessary preparation information to UEs while minimizing additional signaling overhead through efficient reuse of existing communication resources.
Data Source
AI summary
The US DoD is moving to incorporate 5G, particularly for sidelinks networks. 5G sidelink network are desired to operate at company, platoon, and squad levels independent of connection to 5G base stations (gNB). The 5G sidelink standards, as defined by 3GPP, cannot operate under active jamming at expected threat levels. The sidelink standards are defined for commercial use and cannot withstand active jamming. Various prior art uses beamforming, directionally beamformed MIMO, and even distributed MIMO as potential options to address active jamming. The SWAP-C and standards of the 5G UEs are not conducive to these anti-jamming techniques. A solution is described that uses the 5G sidelink physical layer with modifications at the control layer to avoid denial of the S-SSB. Intra-, inter-squad, and squad-to-command post communications may use the solution to avoid denial of the 5G sidelink.