PERFORMANCE ANALYSIS OF VARIABLE-RATE FEC FOR MULTIMEDIA RADIO-COMMUNICATION

One of the most important topics of recent years is use of multimedia technology in radio systems for video, voice and data transmission. On the other hand, a major problem in such systems is the occurrence of errors due to multipath or interference noise. Forward error correction (FEC) is commonly used as a means of eliminating these errors. When employing the FEC technique, it is important to ensure that coding rate and coding gain requirements are met. In multimedia systems, however, the requirements differ with the type of media involved such as real-time voice, real-time video and data transmission. This paper proposes a variable-rate FEC method for multimedia systems as a means of overcoming this problem. The paper begins by presenting an information box and an ATM wireless LAN as examples of multimedia radio communication, and describes how the proposed variable-rate FEC method can be applied to these systems. Next, it shows in some detail how the ATM cells used in the variable-rate FEC are constructed. Then, it analyzes the effects of variable-rate FEC by employing a parameter called the Information Transmission Rate (ITR), which is defined as the product of the throughput rate and the coding rate. Finally, it shows the effects which the variable-rate FEC has on a typical quantity of traffic.