<p>Vehicular networks increasingly require reliable and adaptive task execution frameworks capable of handling rapid mobility, varying traffic scenarios, variable network conditions, and diverse task semantics. This work proposes a risk-sensitive and semantic-aware computation offloading framework for mobility-coupled vehicular networks. To handle delay and energy consumption uncertainty, the offloading process is modeled using Conditional Value-at-Risk (CVaR), which captures the expected cost in adverse conditions. A binary offloading model is developed that accounts for vehicle dynamics, semantic task priorities, channel variability, and Roadside Unit (RSU) availability. We introduce a stochastic vehicle-to-RSU association model, formulated through spatial-temporal connectivity probabilities, and analyze its properties under mobility-induced uncertainty. The overall system cost is redefined using a CVaR-based risk metric to capture worst-case performance. A joint optimization problem is formulated to minimize the CVaR of a composite cost function combining service delay and energy usage, subject to binary offloading constraints. This problem is solved using a Lyapunov-augmented Double Deep Q-Learning (L-DDQL), which enables distributed learning of optimal offloading decisions under dynamic network conditions. Simulation results validate that the proposed method reduces latency by 8.6% compared with DDPG, 16.5% compared with DQN, and 33.8% compared with the random method. Moreover, it also minimizes the energy consumption by 5.6% compared with DDPG, 9.6% compared with DQN, and 32.0% compared with the random method.</p>

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A risk-sensitive and semantic-aware task execution framework for mobility-coupled vehicular networks with CVaR and DRL

  • Kalim Qureshi,
  • kashif Bilal

摘要

Vehicular networks increasingly require reliable and adaptive task execution frameworks capable of handling rapid mobility, varying traffic scenarios, variable network conditions, and diverse task semantics. This work proposes a risk-sensitive and semantic-aware computation offloading framework for mobility-coupled vehicular networks. To handle delay and energy consumption uncertainty, the offloading process is modeled using Conditional Value-at-Risk (CVaR), which captures the expected cost in adverse conditions. A binary offloading model is developed that accounts for vehicle dynamics, semantic task priorities, channel variability, and Roadside Unit (RSU) availability. We introduce a stochastic vehicle-to-RSU association model, formulated through spatial-temporal connectivity probabilities, and analyze its properties under mobility-induced uncertainty. The overall system cost is redefined using a CVaR-based risk metric to capture worst-case performance. A joint optimization problem is formulated to minimize the CVaR of a composite cost function combining service delay and energy usage, subject to binary offloading constraints. This problem is solved using a Lyapunov-augmented Double Deep Q-Learning (L-DDQL), which enables distributed learning of optimal offloading decisions under dynamic network conditions. Simulation results validate that the proposed method reduces latency by 8.6% compared with DDPG, 16.5% compared with DQN, and 33.8% compared with the random method. Moreover, it also minimizes the energy consumption by 5.6% compared with DDPG, 9.6% compared with DQN, and 32.0% compared with the random method.