论文标题
通过无线网络中低级近似的强大时钟同步
Robust Clock Synchronization via Low Rank Approximation in Wireless Networks
论文作者
论文摘要
时钟同步已成为无线网络中的关键设计目标，因为它在许多应用中的重要性。但是，由于无线链接由于不可靠的通道条件而容易出现随机网络延迟，因此通常很难在无线节点之间实现准确的时钟同步。这封信提出了基于低等级矩阵近似的稳健时钟同步算法，在存在随机网络延迟的情况下，能够纠正时间戳。我们设计了一个基于低等级的最大似然估计器（MLE），以共同估计时钟偏移，并在双向消息交换机制下，假设高斯延迟分布，时钟偏斜。通过将时间戳校正问题制定为低等级近似问题，我们可以解决奇异值分解（SVD）域中的问题，也可以通过核标准最小化解决。数值结果表明，所提出的方案可以校正嘈杂的时间戳，从而比MLE获得更强的同步性能。
Clock synchronization has become a key design objective in wireless networks for its essential importance in many applications. However, as the wireless link is prone to random network delays due to unreliable channel conditions, it is in general difficult to achieve accurate clock synchronization among wireless nodes. This letter proposes robust clock synchronization algorithms based on low rank matrix approximation, which are able to correct timestamps in the presence of random network delays. We design a low rank approximation based maximum likelihood estimator (MLE) to jointly estimate the clock offset and clock skew under the two-way message exchange mechanism assuming Gaussian delay distribution. By formulating the timestamp correction problem into a low rank approximation problem, we can solve the problem in the singular value decomposition (SVD) domain and also via nuclear norm minimization. Numerical results show that the proposed schemes can correct noisy timestamps and thus achieve more robust synchronization performance than the MLE.
