Building a Noisy Multipath Channel Emulator for Single or Multicarrier Communication Systems

This paper suggests a method for a cheap and easy to use practical multipath noisy channel emulator to evaluate a communication system. The circuitry for the channel are realized and implemented using the FPGA technology due to its flexibility and parallelism. The user can simply modify the design to meet the requirement for any channel without any complicated procedures using Simulink/System Generator package. Building such a test bench is crucial to examine the behavior of the communication system over the specified channel to inspect its efficiency and signal quality. This test bench can be used to study a complicated wireless communication system like the Orthogonal Frequency Division Multiplexing (OFDM). The OFDM is considered complicated compared to other single carrier systems because the OFDM symbol's power changes at every instance. Therefore, an efficient, cheap and flexible equipment are important to analyze the OFDM by the scholars who cannot afford the expensive laboratory equipment. The test bench can be, easily, modified to work with other single carrier systems. The flexibility of the suggested system comes from the simplified control bus (only 1 bit is required) and the generalized approach for the channel design to satisfy the necessities for various communication systems. The tested OFDM system has a 64 level QAM and 16 subcarriers. A gray scale image is used as a test data source transmitted over the ITU outdoor channel model.