Latency (engineering)

About: Latency (engineering) is a research topic. Over the lifetime, 3729 publications have been published within this topic receiving 39210 citations. The topic is also known as: lag.

An Enhanced Fast Handover with Low Latency for Mobile IPv6

Abstract: One of the most important challenges in Mobile IPv6 is to provide the service for a mobile node to maintain its connectivity to the Internet when it moves from one domain to another, which is referred to as handover. Here we deal with the fast handover problem, which is to provide rapid handover service for the delay-sensitive and real-time applications. In this paper, we propose an enhanced fast handover scheme for Mobile IPv6. In our scheme, each AR (Access Router) maintains a CoA (Care of Address) table and generates the new CoA for the MN that will move to its domain. At the same time, the binding updates to home agent and correspondent node are to be performed from the time point when the new CoA for MN is known by PAR (Previous AR). Also the localized authentication procedure cooperated with the proposed scheme is provided. For the comparison with the existing fast handover scheme, detailed performance evaluation is performed. From the evaluation results, we can see that the proposed enhanced fast handover scheme can achieve low handover latency and low packet delay.

Latency-Driven Cooperative Task Computing in Multi-user Fog-Radio Access Networks

Abstract: Fog computing is emerging as one promising solution to meet the increasing demand for ultra-low latency services in wireless networks. Taking a forward-looking perspective, we propose a Fog-Radio Access Network (F-RAN) model, which utilizes the existing infrastructure, e.g., small cells and macro base stations, to achieve the ultra-low latency by joint computing across multiple F-RAN nodes and near-range communications at the edge. We treat the low latency design as an optimization problem, which characterizes the tradeoff between communication and computing across multiple F-RAN nodes. Since this problem is NP-hard, we propose a latency-driven cooperative task computing algorithm with one-for-all concept for simultaneous selection of the F-RAN nodes to serve with proper heterogeneous resource allocation for multi-user services. Considering the limited heterogeneous resources shared among all users, we advocate the one-for-all strategy for every user taking other's situation into consideration and seek for a "win-win" solution. The numerical results show that the low latency services can be achieved by F-RAN via latency-driven cooperative task computing.

LASER: a scalable response prediction platform for online advertising

Abstract: We describe LASER, a scalable response prediction platform currently used as part of a social network advertising system. LASER enables the familiar logistic regression model to be applied to very large scale response prediction problems, including ones beyond advertising. Though the underlying model is well understood, we apply a whole-system approach to address model accuracy, scalability, explore-exploit, and real-time inference. To facilitate training with both large numbers of training examples and high dimensional features on commodity clustered hardware, we employ the Alternating Direction Method of Multipliers (ADMM). Because online advertising applications are much less static than classical presentations of response prediction, LASER employs a number of techniques that allows it to adapt in real time. LASER models can be divided into components with different re-training frequencies, allowing us to learn from changes in ad campaign performance frequently without incurring the cost of retraining larger, more stable sections of the model. Thompson sampling during online inference further helps by efficiently balancing exploration of new ads with exploitation of long running ones. To enable predictions made with the most recent feature data, we employ a range of techniques, including extensive caching and lazy evaluation, to permit real time, low latency scoring. LASER models are defined using a configuration language that ties together the training, validation, and inference pieces and permits even non-programming analysts to experiment with different model structures without modifications to code or interruptions to running servers. Finally, we show via extensive offline experiments and online A/B tests that this system provides significant benefits to prediction accuracy, gains in revenue and CTR, and reductions in system latency.

A virtual infrastructure based on honeycomb tessellation for data dissemination in multi-sink mobile wireless sensor networks

Abstract: A new category of intelligent sensor network applications emerges where motion is a fundamental characteristic of the system under consideration. In such applications, sensors are attached to vehicles, or people that move around large geographic areas. For instance, in mission critical applications of wireless sensor networks (WSNs), sinks can be associated to first responders. In such scenarios, reliable data dissemination of events is very important, as well as the efficiency in handling the mobility of both sinks and event sources. For this kind of applications, reliability means real-time data delivery with a high data delivery ratio. In this article, we propose a virtual infrastructure and a data dissemination protocol exploiting this infrastructure, which considers dynamic conditions of multiple sinks and sources. The architecture consists of 'highways' in a honeycomb tessellation, which are the three main diagonals of the honeycomb where the data flow is directed and event data is cached. The highways act as rendezvous regions of the events and queries. Our protocol, namely hexagonal cell-based data dissemination (HexDD), is fault-tolerant, meaning it can bypass routing holes created by imperfect conditions of wireless communication in the network. We analytically evaluate the communication cost and hot region traffic cost of HexDD and compare it with other approaches. Additionally, with extensive simulations, we evaluate the performance of HexDD in terms of data delivery ratio, latency, and energy consumption. We also analyze the hot spot zones of HexDD and other virtual infrastructure based protocols. To overcome the hot region problem in HexDD, we propose to resize the hot regions and evaluate the performance of this method. Simulation results show that our study significantly reduces overall energy consumption while maintaining comparably high data delivery ratio and low latency.

Topology adaptive network-on-chip design and implementation

Abstract: Network-on-chip designs promise to offer considerable advantages over the traditional bus-based designs in solving the numerous technological, economic and productivity problems associated with billion-transistor system-on-chip development. The authors believe that different types of networks will be required, depending on the application domain. Therefore, a very flexible network design is proposed that is highly scalable, and can be easily changed to accomodate various needs. A network-on-chip design, realised as part of the platform that the authors are developing for reconfigurable systems, is presented. This design is suitable for building networks with irregular topologies, and with low latency and high throughput.