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Submitted by admin on Wed, 10/23/2024 - 01:52

We consider a semantics-aware communication system, where timeliness is the semantic measure, with a source which maintains the most current version of a file, and a network of $n$ user nodes with the goal to acquire the latest version of the file. The source gets updated with newer file versions as a point process, and forwards them to the user nodes, which further forward them to their neighbors using a memoryless gossip protocol. We study the average version age of the network in the presence of $\tilde {n}$ jammers that disrupt inter-node communications, for the connectivity-constrained ring topology and the connectivity-rich fully connected topology. For the ring topology, we construct an alternate system model of mini-rings and prove that the version age of the original model can be sandwiched between constant multiples of the version age of the alternate model. We show in a ring network that when the number of jammers scales as a fractional power of the network size, i.e., $\tilde n= cn^{\alpha }$ , the version age scales as $\sqrt {n}$ when $\alpha < {}{}\frac {1}{2}$ , and as $n^{\alpha }$ when $\alpha \geq {}{}\frac {1}{2}$ . As the version age of a ring network without any jammers scales as $\sqrt {n}$ , our result implies that the version age with gossiping is robust against up to $\sqrt {n}$ jammers in a ring network. We then study the connectivity-rich fully connected topology, where we derive a greedy approach to place $\tilde {n}$ jammers to maximize the age of the resultant network, which uses the jammers to isolate as many nodes as possible, thereby consolidating all links into a single mini-fully connected network. We show in this network that version age scales as $\log {n}$ when $\tilde {n}=cn\log {n}$ and as $n^{\alpha -1}$ , $1 < \alpha \leq 2$ when $\tilde {n}=cn^{\alpha }$ , implying that the network is robust against $n\log {n}$ jammers, since the age in a fully connected network without jammers scales as $\log {n}$ . Finally, we present simulation results to support our theoretical findings.

Priyanka Kaswan
Sennur Ulukus