Topic
Timing Synchronization Function
About: Timing Synchronization Function is a research topic. Over the lifetime, 46 publications have been published within this topic receiving 688 citations.
Papers
TL;DR: CS-MNS is able to achieve microsecond networkwide synchronization accuracy for single-hop or multiple-hop network topologies in mobile or static wireless ad hoc and sensor networks and shows better accuracy than the multihop ad hoc TSF (MATSF) and the automatic self-time-correcting procedure (ASP) methods under similar scenarios.
Abstract: Mutual network synchronization is a distributed method in which geographically separated clocks align their times to one another without the need of reference or master clocks. Mutual network synchronization is attractive for wireless ad hoc and sensor networks, because there is no overhead associated with the discovery, management, and tracking of specific nodes with reference clocks. Existing mutual network synchronization methods, however, make use of physical and medium access control layers that are proprietary and not widely available. This paper presents clock sampling mutual network synchronization (CS-MNS). CS-MNS is able to achieve microsecond networkwide synchronization accuracy for single-hop or multiple-hop network topologies in mobile or static wireless ad hoc and sensor networks. Different from existing mutual network synchronization approaches, the timing information is exchanged explicitly by using periodic time stamp packets. These packets can be, for instance, the same beacons used in the IEEE 802.11 or IEEE 802.15.4 standards, which, to the best of our knowledge, makes CS-MNS the first mutual network synchronization method compatible to these popular standards. A CS-MNS node adjusts the time and frequency of its clock recursively in the time domain by multiplying the time of its clock by a factor that is updated with any newly received time stamp. Sufficient stability conditions are derived via the discrete Lyapunov direct method. Additionally, CS-MNS enables several beacon medium access approaches, which are discussed and analyzed. Thorough numerical results are presented, which demonstrate at least one and two orders of magnitude improvement in scalability and accuracy, respectively, relative to the IEEE 802.11 timing synchronization function (TSF). CS-MNS also shows better accuracy than the multihop ad hoc TSF (MATSF) and the automatic self-time-correcting procedure (ASP) methods under similar scenarios. The latter is achieved with less complexity and with fully compatible IEEE 802.11 beacons.
93 citations
Patent•
14 Jan 2005TL;DR: In this paper, a method for power management of a direct wireless link between two wireless devices is disclosed. But it is not shown how to manage the power in such a link.
Abstract: Disclosed herein are exemplary techniques for managing power in a direct wireless link between two wireless devices. The present invention provides at least three direct link power management techniques: Fast Resumption Mode (FRM) wherein the direct link is resumed automatically at a specified timing synchronization function (TSF); Slow Resumption Mode (SRM) wherein the direct link may be resumed by sending a Resume-Request via the access point; and Reverse Polling (RP), wherein one peer station of the direct link is continually awake and the other peer station uses reverse polling to start a service period. Thus, a method for power management of a direct wireless link between two wireless devices is disclosed. The method comprising the steps of establishing a direct wireless link between the first wireless device and the second wireless device; transmitting, from a first wireless device, a frame having a time value; receiving, at the second wireless device, the frame from the first wireless device; suspending the direct wireless link a duration determined based on the time value; and resuming the direct wireless link at a time determined based on the time value.
81 citations
27 Mar 2003
TL;DR: A more efficient algorithm is proposed in this paper that synchronizes the clock more accurately and is able to synchronize the clock within 100 /spl mu/s when the number of stations is more than 300, a big improvement over the current best algorithm and the 802.11 specified protocol.
Abstract: The IEEE 802.11 standards support the peer-to-peer mode independent basic service set (IBSS), which is an ad hoc network with all its stations within each other's transmission range. In an IBSS, it is important that all stations are synchronized to a common clock. Synchronization is needed for frequency hopping and power saving. The synchronization mechanism specified in the IEEE 802.11 standards has a severe scalability problem. The probability that stations may get out of synchronization is pretty high in large IBSS. A new synchronization algorithm has been proposed for large-scale ad hoc networks. We propose a more efficient algorithm in this paper that synchronizes the clock more accurately. We are able to synchronize the clock within 100 /spl mu/s when the number of stations is more than 300. This is a big improvement over the current best algorithm and the 802.11 specified protocol. To our best knowledge, the current best algorithm can synchronize the clock within 550 /spl mu/s for a 300-station network. The 802.11 standard protocol can have clock drift over 5000 /spl mu/s for the same network.
72 citations
Patent•
26 Jul 2006
TL;DR: In this paper, a method is used by a mesh point that includes one or more step of receiving one of a beacon and probe response from an other mesh point, setting a state of whether the mesh point is already synchronized with one or multiple peers to true and performing a beacon timing synchronization function when the mesh points are in the unsynchronized state and the other mesh points requests synchronization from a peer mesh point.
Abstract: A method is used by a mesh point that includes one or more step of receiving one of a beacon and probe response from an other mesh point; setting a state of whether the mesh point is already synchronized with one or more peers to true and performing a beacon timing synchronization function when the mesh point is in the unsynchronized state and the other mesh point requests synchronization from a peer mesh point; adding an identity of the other mesh point to a database of beacon senders maintained by the mesh point and performing a beacon timing synchronization function when the mesh point and the other mesh point are both synchronized; and providing indications of whether the mesh point supports synchronization, requests synchronization from a peer mesh point, and is already synchronized with one or more peer.
52 citations
Patent•
3 Apr 2008
TL;DR: In this article, a transceiver node transitions a wireless network device from an inactive mode to an active mode, which occurs a wake-up period before an expected one of delivery traffic indication message (DTIM) beacons the wakeup period being based on the inactive mode clock.
Abstract: A wireless network device includes an inactive mode clock, a transceiver module, and a control module. The transceiver module transitions the wireless network device from an inactive mode to an active mode. The transition occurs a wake-up period before an expected one of delivery traffic indication message (DTIM) beacons the wake-up period being based on the inactive mode clock. The control module generates first and second correction values that respectively compensate for hardware/software delays of the wireless network device and drift of the inactive mode clock, to ajust (166, 174, 184, 194, 240, 244) the wake-up period during operation, wherein said first correction value is based on a number of missed DTIM beacon and said second correction value is based on timestamps received from a remote device.
40 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2019 | 4 |
| 2018 | 3 |
| 2017 | 1 |
| 2016 | 1 |
| 2015 | 5 |