AI 中文总结
针对大规模随机激活的无线传感器网络，提出AoI高效的D-TFDA机制，通过建模与算法优化实现更低的平均信息年龄。
AI 中文摘要
频谱划分技术的日益普及使得多个正交资源上的上行链路并发传输成为可能，但针对大规模随机激活的传感器网络，兼具低开销与有效信息新鲜度的接入设计仍未得到充分研究。本文应用信息年龄（Age of Information, AoI）来衡量信息新鲜度，提出一种AoI高效的确定性时频分布式接入（Deterministic Time-Frequency Distributed Access, D-TFDA）机制。D-TFDA通过基于周期性令牌的时频结构结合集中式配置与分布式操作，为传感器提供无冲突且可预测的传输机会，同时无需大量运行时开销。我们开发了一个分析框架，利用令牌分配模式的周期性，通过一维离散时间马尔可夫链（Discrete-Time Markov Chain, DTMC）对每个传感器的稳态局部状态建模，以表征长期平均AoI（Average AoI, AAoI）。我们进一步揭示令牌分配模式的结构特性，识别出AoI等价令牌簇，这大幅缩小了AAoI最优令牌分配问题的搜索空间。基于该结构，我们将简化后的问题建模为线性规划（Linear Programming, LP）问题，并开发了AAoI最优搜索算法以及一种复杂度更低的受拍卖启发的启发式算法。仿真结果验证了所提出的AAoI分析，证明了令牌分配算法的有效性，并显示D-TFDA通过避免冲突和利用异构传感器-资源传输可靠性，相较于优化的随机接入基线实现了显著更低的AAoI。
英文摘要
The increasing adoption of spectrum-division techniques enables concurrent uplink transmissions over multiple orthogonal resources, yet low-overhead access design with effective information freshness remains insufficiently studied for large-scale randomly activated sensor networks. In this paper, we apply the age of information (AoI) to measure information freshness and propose an AoI-efficient deterministic time-frequency distributed access (D-TFDA) mechanism. D-TFDA combines centralized configuration and distributed operation through a periodic token-based time-frequency structure, which provides sensors with collision-free and predictable transmission opportunities without considerable run-time overhead. We develop an analytical framework to characterize the long-term average AoI (AAoI) by exploiting the periodicity of the token assignment pattern and modeling the steady local state of each sensor with a one-dimensional discrete-time Markov chain (DTMC). We further reveal structural properties of the token assignment pattern and identify AoI-equivalent token clusters, which substantially reduce the search space of the AAoI-optimal token allocation problem. Based on this structure, we formulate the reduced problem as a linear programming (LP) problem and develop an AAoI-optimal search algorithm, together with an auction-inspired heuristic algorithm of lower complexity. Simulation results validate the proposed AAoI analysis, demonstrate the effectiveness of the token allocation algorithms, and show that D-TFDA achieves substantially lower AAoI than optimized random access baselines by avoiding collisions and exploiting heterogeneous sensor--resource transmission reliability.
