Voice Data Communication Research Articles

Study of voice data communication using network streams on dataflow programming

In this paper, we implement a voice data communications between sender and receiver through Wi-Fi. The system was designed and implemented using network stream protocol which was developed by National Instruments on Lab-VIEW between two devices. The device which acts as the sender was My-RIO board and the receiver device was Personal Computer. The voice data communication system was tested by observing the effect of various buffer sizes on the throughput, latency and CPU usage. The result showed that the larger the buffer size being used, the throughput values were also getting bigger. However, particular buffer size made the throughput became saturated. The change on the buffer size also directly affects CPU usage. It seemed that the buffer size did not affect latency significantly. It showed that the latency was stable with an average of 13 milliseconds on voice data transmission.

Analysis and modeling of service impacts on system activities, resource workloads and service performance on computer and network systems

Various services running on computer and network systems compete for shared system resources. Impacts of services on system activities, workloads and performance need to be understood, modeled and used in many system planning and control activities. Due to complex interactions of many system resources e.g., CPU, memory and network and sharing of system resources by various services running at the same time, it is challenging to uncover and model relations of services with their resource workloads and resulting service performance. This paper presents our methodology that uses statistical analysis techniques to analyze empirical data of computer and network dynamics and uncover significant variables of system activities, resource workloads and service performance that are affected by services. Statistical modeling techniques are also employed in our methodology to build quantitative models of service impacts on system resource workloads and service performance. The methodology is illustrated and tested on three services of voice data communication, motion detection, and data encryption.

Models of dynamic relations among service activities, system state and service quality on computer and network systems

Service quality on computer and network systems has become increasingly important as many conventional service transactions are moved online. Service quality of computer and network services can be measured by the performance of the service process in throughput, delay, and so on. On a computer and network system, competing service requests of users and associated service activities change the state of limited system resources which in turn affects the achieved service quality. Modeling dynamic relations of service activities, system state and service quality is required to determine if users' service requests and requirements of service quality can be satisfied by the system with limited resources and how the system and service configuration can be adapted to meet service quality requirements. This paper presents our empirical study to establish activity-state-quality models for a voice communication service. We run experiments to collect system dynamics data under various service conditions and use statistical techniques to analyze experimental data and build activity-state-quality models. The results reveal four major types of dynamic relations among service activity parameters, system resource state, and the network throughput - a measure of achieved service quality for the voice communication service. Although delay-related measures are also important for voice data communication, they are not collected in this study. Five system state variables concerning the memory, CPU, process and IP resources are uncovered to be affected by service activity parameters significantly and be associated with the achieved service quality closely. We also obtain an insight about increasing the size of the buffer which holds voice data before transmission over the network to alleviate the workload on system resources and maintain the network throughout when the number of client requests and the client requirement in voice quality increase.

A load-controlled scheduling scheme for integrated voice-data communication on high-speed LANs/MANs

A new dynamic bandwidth-allocation (or rate-control) strategy that can be employed for integrating multimedia traffic on a class of high-speed fiber optic local and metropolitan area networks (LANs/MANs) is investigated. This new scheme is adapted from the original work by Limb on load-controlled-scheduling-of-traffic (LOCOST) mechanism, which employs channel feedback for proper distributed control operation. Although the mechanism is quite general for integrating diverse traffic types, the specific focus of this paper is on the integration of packet voice with data. The medium access control is simple, and is fully asynchronous and distributed which make it easy to implement. The necessary control functions are performed locally and independently at each data station based on a single parameter called its packet allowance, while each voice station can transmit a voice packet whenever it can. A gated global queue model is formulated to approximately analyze this system, and simulation results are also included to study the protocol's performance.

Asymptotic Analysis of an Integrated Digital Network

A queueing model for an integrated digital network for voice-data communications consisting of c data and v voice transmission channels both with exponential arrival and service distributions is considered. The data traffic is allowed to use any unoccupied voice channels, but any new voice traffic has preemptive priority over the data traffic being served in a voice channel. By applying singular perturbation techniques, an asymptotic solution is constructed for the stationary distribution of the number of voice and data in the system using a parameter that measures the fact that the arrival and service rates for data are much larger than those for voice. For the case $v = 1$ and $c = 1$, it is shown that asymptotic solution agrees with the expansion of the exact solution. A computational algorithm,, based on the asymptotic solution, is given for systems with arbitrary v and c. Numerical comparisons are given for several examples.

Integrated voice-data communication over high-speed fiber optic networks

Voice-data integration over emerging high-speed fiber-optic LANs and MANs employing unidirectional buses for information transfer is addressed. Packet voice characteristics and requirements are examined, as are the characteristics of fiber-optic networks. Both train-oriented and non-train-oriented protocols are discussed and compared. >

Providing Integrated Continuous Voice/Data Services to Mobile Terminals through a Power-Limited Satellite Transponder

In the very near future, Australia plans to provide integrated voice-data communication services to mobiles through its MOBILESAT system. An important component of these services would be the ability to support continuous voice and data calls between mobiles and certain fixed stations. In the context of this system, this paper describes a protocol for these services and analyzes them for the realistic situation where the satellite transponder is power-limited. Using the bursty nature of voice, an “over-assignment” strategy is proposed to efficiently utilize the satellite's resources. The problems inherent in this basic scheme are described and some simple control strategies are proposed which may be used to avoid these in an actual system.

An Integrated Voice-Data Communication System for VHF Links

In this work, a combined amplitude-phase modulation communication system is considered. Amplitude modulation is used to transmit a voice signal, and phase modulation is used for data transmission. Such a scheme was studied as a possible realization of a data channel between aircraft and ground station, which can be introduced without great modifications of the actual on-board equipment. The performance of the combined modulation system is evaluated through a computer simulation.