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Performance Evaluation of a Packetized Voice System Simulation Study
Introduction of the packet switching technique into digitized voice communication may afford great advantages in efficient use of the channel, compared to both circuit-switched and DSI systems. Detailed characteristics, however, have not been obtained because of difficulty in the exact analysis. Hence, simulation models are developed in this paper for the packetized voice transmission system, and various characteristics such as transmission delays and loss probability of voice packets are obtained. We further evaluate three types of voice packet reassembly strategy at t he receiving terminal, and obtain the optimal packet length, which keeps each of overall packet transmission delay and packet loss probability less than a certain permissible values. Comparison among three strategies is also stated
Skew detection and compensation for Internet audio applications
Long lived audio streams, such as music broadcasts, and small differences in clock rates lead to buffer underflow or overflow events in receiving applications that manifest themselves as audible interruptions. We present a low complexity algorithm for detecting clock skew in network audio applications that function with local clocks and in the absence of a synchronization mechanism. A companion algorithm to perform skew compensation is also presented. The compensation algorithm utilises the temporal redundancy inherent in audio streams to make inaudible playout adjustments. Both algorithms have been implemented in a simulator and in a network audio application. They perform effectively over the range of observed clock rate differences and beyond
Space Shuttle/TDRSS communication and tracking systems analysis
In order to evaluate the technical and operational problem areas and provide a recommendation, the enhancements to the Tracking and Data Delay Satellite System (TDRSS) and Shuttle must be evaluated through simulation and analysis. These enhancement techniques must first be characterized, then modeled mathematically, and finally updated into LinCsim (analytical simulation package). The LinCsim package can then be used as an evaluation tool. Three areas of potential enhancements were identified: shuttle payload accommodations, TDRSS SSA and KSA services, and shuttle tracking system and navigation sensors. Recommendations for each area were discussed
Business Case and Technology Analysis for 5G Low Latency Applications
A large number of new consumer and industrial applications are likely to
change the classic operator's business models and provide a wide range of new
markets to enter. This article analyses the most relevant 5G use cases that
require ultra-low latency, from both technical and business perspectives. Low
latency services pose challenging requirements to the network, and to fulfill
them operators need to invest in costly changes in their network. In this
sense, it is not clear whether such investments are going to be amortized with
these new business models. In light of this, specific applications and
requirements are described and the potential market benefits for operators are
analysed. Conclusions show that operators have clear opportunities to add value
and position themselves strongly with the increasing number of services to be
provided by 5G.Comment: 18 pages, 5 figure
Supporting Real-Time Applications in an Integrated Services Packet Network: Architecture and Mechanism
This paper considers the support of real-time applications in an Integrated Services Packet Network (ISPN). We first review the characteristics of real-time applications. We observe that, contrary to the popular view that real-time applications necessarily require a fixed delay bound, some real-time applications are more
flexible and can adapt to current network conditions. We then propose an ISPN architecture that supports two distinct kinds of real-time service: guaranteed service, which is the traditional form of real-time service discussed in most of the literature and involves pre-computed worst-case delay bounds, and predicted service,
which uses the measured performance of the network in computing delay bounds. We then propose a packet scheduling mechanism that can support both of these real-time services as well as accommodate datagram traffic. We also discuss two other aspects of an overall ISPN architecture: the service interface and the admission control criteria.Research at MIT was supported by DARPA through NASA Grant
NAG 2-582, by NSF grant NCR-8814187, and by DARPA and NSF
through Cooperative Agreement NCR-8919038 with the Corporation
for National Research Initiatives
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