Secure Video Streaming in Heterogeneous Small Cell Networks with Untrusted Cache Helpers

TL;DR

This paper proposes a joint caching and scalable video coding scheme for secure video streaming in small cell networks with untrusted helpers, optimizing power and secrecy under imperfect CSI.

Contribution

It introduces a novel joint caching and transmission framework with robust optimization and algorithms for secure, power-efficient video delivery in heterogeneous small cell networks.

Findings

Significant power savings compared to baseline schemes.

Enhanced secrecy performance with the proposed methods.

Effective joint caching and cooperative transmission strategies.

Abstract

This paper studies secure video streaming in cache-enabled small cell networks, where some of the cache-enabled small cell base stations (BSs) helping in video delivery are untrusted. Unfavorably, caching improves the eavesdropping capability of these untrusted helpers as they may intercept both the cached and the delivered video files. To address this issue, we propose joint caching and scalable video coding (SVC) of video files to enable secure cooperative multiple-input multiple-output (MIMO) transmission and, at the same time, exploit the cache memory of both the trusted and untrusted BSs for improving the system performance. Considering imperfect channel state information (CSI) at the transmitters, we formulate a two-timescale non-convex mixed-integer robust optimization problem to minimize the total transmit power required for guaranteeing the quality of service (QoS) and secrecy during video streaming. We develop an iterative algorithm based on a modified generalized Benders decomposition (GBD) to solve the problem optimally, where the caching and the cooperative transmission policies are determined via offline (long-timescale) and online (short-timescale) optimization, respectively. Furthermore, inspired by the optimal algorithm, a low-complexity suboptimal algorithm based on a greedy heuristic is proposed. Simulation results show that the proposed schemes achieve significant gains in power efficiency and secrecy performance compared to several baseline schemes.