Integration of Voice Traffic with Aysnchronous Transfer Mode (ATM) Technology

This proposal address the inefficiences inherent in transmitttng tactical voice over ATM networks using Constant Bit Rate (CBR) methods. It proposes to perform the research and development necessary to design a Variable Bit Rate (VBR) interface that will tailor the bandwidth used by tactical voice traffic to the actual syllabic speech activity on the individual channels. This interface will allow ATM switches to dynamically allocate bandwidth to voice or other (e.g., VTC) traffic thus improving group efficiencies. The major areas of research will be the relationship between the activity factors for busy channels and the acceptable freezeout factor, i.e., percentage of speech lost due to clipping and trunk unavailability in ACUS. The research will serve to develop an algorithm for channel interpolation which will take into account the number of channels in a DTG and the acceptable tactical Grade Of Service (GOS). As a result of this work, a frame structure and connection coding algorithm will be developed and a system architecture to support ATM will be defined. Additional work will involve developing design specifications for the software elements and the design of a prototype hardware platform. This R&D phase will prove technical feasibility of a tactical voice VBR interface. In the next phase, a stand-alone prototype will be built and tested. Later, the software developed will be ported into a COTS ATM switch as an AAL. Knowledge gained from this work would support development of a standard AAL for tactical voice VER interface.