In this paper, we investigate the impact of channel probing and reservation on the Age of Information (AoI) in energy-harvesting (EH) random access networks, where each source relies solely on harvested energy for status updating. To mitigate collisions, each node may expend a small amount of energy to send a probing signal before transmission, and a successful probe reserves the channel in the current slot. If probing fails, the node can either remain silent, termed strict avoid free competition (SAFC), attempt data transmission with a certain probability, termed reserved nodes competition (RUC), or adopt all-active nodes competition (AUC), where all energy-sufficient nodes may contend regardless of whether they probed. We derive closed-form expressions for the network-average AoI under these three schemes and validate them via simulations. The results show that AUC consistently achieves the lowest AoI by shortening the waiting time to convert harvested energy into successful updates. This finding challenges the conventional wisdom that strict collision avoidance is always optimal in energy-constrained systems, since allowing additional contention can effectively amortize probing overhead across more transmission opportunities. Comparisons with EH-enabled slotted ALOHA further show that probing-based access significantly outperforms direct transmission in energy-constrained regimes, highlighting channel probing as an effective approach to improving freshness.

翻译：本文研究了信道探测与预留对能量收集随机接入网络中信息时效的影响，其中每个源节点仅依靠采集的能量进行状态更新。为减少冲突，每个节点可在传输前消耗少量能量发送探测信号，成功探测即可在当前时隙预留信道。若探测失败，节点可采用三种策略：严格避免自由竞争（SAFC）即保持静默；保留节点竞争（RUC）即按一定概率尝试数据传输；或全活跃节点竞争（AUC）即所有能量充足的节点无论是否探测均可参与竞争。我们推导了这三种策略下网络平均信息时效的闭式表达式，并通过仿真验证。结果表明，AUC通过缩短将采集能量转化为成功更新的等待时间，始终能获得最低的AoI。这一发现挑战了传统认知——在能量受限系统中严格避免冲突总是最优的，因为允许额外竞争能有效将探测开销分摊至更多传输机会。与具有能量收集能力的时隙ALOHA对比进一步表明，在能量受限场景下，基于探测的接入显著优于直接传输，凸显信道探测作为提升信息新鲜度的有效途径。