An OpenCores/Opensource based Embedded System-on-Chip Platform for Voice over Internet Protocol

Today, with the explosion of the IP network protocol, communication traffic is mainly dominated by data traffic, unlike in the past it was dominated by telephony driven voice. This phenomenon has lead to the emergence of voice over data (VOIP) equipment that can carry voice, data and also video on a single network. The idea behind VOIP is to use the IP network for voice services as an alternative to the public switched telecommunication network (PSTN). The advantages over traditional telephony include: lower costs per call, especially for long distance calls, and lower infrastructure cost compared to the PSTN. The market for VOIP equipment has increased dramatically and a lot of solutions are proposed to the research and industry communities. Each specialised paper that appears shows that VOIP has an important place in the telephony market, especially in enterprise and public domain areas. The main challenges in designing a VOIP application are the quality of service (QoS), the capacity of the gateways and real time computation. Factors affecting the QoS are line noise, echo cancellation, the voice coder used, the talker overlap and the Jitter factor. The capacity of the gateway is related to the number of lines that can be supported in an enterprise environment. An integrated hardware-software development environment is needed to deal with real time computation. (Dhir, 2001). Most important VOIP solutions proposed in the market are based on the use of a general purpose processor and a DSP circuit. In these solutions, parts of the application run on software on the general purpose processor and the other part of the application runs on the dedicated DSP hardware to meet some performances requirements. Recently, and with the advance of the microelectronic technology in one hand, and CAD tools in the other hand, it is possible to integrate a whole system into a single integrated FPGA chip. Ended, FPGAs have evolved in an evolutionary and revolutionary way. The evolution process has allowed faster and bigger FPGAs, better CAD tools and better technical support. The revolution process concerns the introduction of high performances multipliers, Microprocessors and DSP functions inside the FPGA circuit. Thus, a new field which integrates VOIP solutions into FPGAs based System on Chip (SoC) is emerging, particularly the field of embedded VOIP based FPGA platform. Contrarily to DSP and general purpose processors, FPGAs enable rapid, cost-effective product development cycles in an environment where target markets are constantly shifting and standards continuously evolving. Most of these offer processing capabilities, a