CR^2: Cost-Aware Risk-Controlled Routing for Wireless Device-Edge LLM Inference

Fuente: arXiv
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Autori principali: Xue, Nan, Chen, Shengkang, Chen, Zhiyong, Yao, Jiangchao, Sun, Yaping, Hu, Zixia, Tao, Meixia
Natura: Preprint
Pubblicazione: 2026
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author Xue, Nan
Chen, Shengkang
Chen, Zhiyong
Yao, Jiangchao
Sun, Yaping
Hu, Zixia
Tao, Meixia
author_facet Xue, Nan
Chen, Shengkang
Chen, Zhiyong
Yao, Jiangchao
Sun, Yaping
Hu, Zixia
Tao, Meixia
contents As large language models (LLMs) move from centralized clouds to mobile edge environments, efficient serving must balance latency, energy consumption, and accuracy under constrained device-edge resources. Query-level routing between lightweight on-device models and stronger edge models provides a flexible mechanism to navigate this trade-off. However, existing routers are designed for centralized cloud settings and optimize token-level costs, failing to capture the dynamic latency and energy overheads in wireless edge deployments. In this paper, we formulate mobile edge LLM routing as a deployment-constrained, cost-aware decision problem, and propose CR^2, a two-stage device-edge routing framework. CR^2 decouples a lightweight on-device margin gate from an edge-side utility selector for deferred queries. The margin gate operates on frozen query embeddings and a user-specified cost weight to predict whether local execution is utility-optimal relative to the best edge alternative under the target operating point. We further introduce a conformal risk control (CRC) calibration procedure that maps each operating point to an acceptance threshold, enabling explicit control of the marginal false-acceptance risk under the full-information utility reference. Experiments on the routing task show that CR^2 closely matches a full-information reference router using only device-side signals before deferral. Compared with strong query-level baselines, CR^2 consistently improves the deployable accuracy-cost Pareto frontier and reduces normalized deployment cost by up to 16.9% at matched accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2605_12001
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CR^2: Cost-Aware Risk-Controlled Routing for Wireless Device-Edge LLM Inference
Xue, Nan
Chen, Shengkang
Chen, Zhiyong
Yao, Jiangchao
Sun, Yaping
Hu, Zixia
Tao, Meixia
Information Theory
Artificial Intelligence
As large language models (LLMs) move from centralized clouds to mobile edge environments, efficient serving must balance latency, energy consumption, and accuracy under constrained device-edge resources. Query-level routing between lightweight on-device models and stronger edge models provides a flexible mechanism to navigate this trade-off. However, existing routers are designed for centralized cloud settings and optimize token-level costs, failing to capture the dynamic latency and energy overheads in wireless edge deployments. In this paper, we formulate mobile edge LLM routing as a deployment-constrained, cost-aware decision problem, and propose CR^2, a two-stage device-edge routing framework. CR^2 decouples a lightweight on-device margin gate from an edge-side utility selector for deferred queries. The margin gate operates on frozen query embeddings and a user-specified cost weight to predict whether local execution is utility-optimal relative to the best edge alternative under the target operating point. We further introduce a conformal risk control (CRC) calibration procedure that maps each operating point to an acceptance threshold, enabling explicit control of the marginal false-acceptance risk under the full-information utility reference. Experiments on the routing task show that CR^2 closely matches a full-information reference router using only device-side signals before deferral. Compared with strong query-level baselines, CR^2 consistently improves the deployable accuracy-cost Pareto frontier and reduces normalized deployment cost by up to 16.9% at matched accuracy.
title CR^2: Cost-Aware Risk-Controlled Routing for Wireless Device-Edge LLM Inference
topic Information Theory
Artificial Intelligence
url https://arxiv.org/abs/2605.12001