A Filtered Multitone (FMT) Implementation with Custom Instructions on an Altera FPGA

Abstract

There is a belief that radio frequencies are running out. However, according to a report from the Federal Communications Commission (FCC) in 2002, a different story was told : At any given time and location, much of the prized spectrum lies idle. At the same time, FCC revealed the fact that, in many bands, spectrum access is a more significant problem than physical scarcity of spectrum, in large part due to legacy command-and-control regulation that limits the ability of potential spectrum users to obtain such access. Hence, as opposed to static spectrum access, dynamic spectrum access (DSA) was proposed to solve the predicament. One such DSA model propose the existence of Primary users (licensed users and Secondary users (unlicensed users). Multicarrier communication technology is adopted to enable the coexistence of PU and SU. Orthogonal Frequency Division Multiplexing (OFDM) technology has been popular for multicarrier communications. A disadvantage for OFDM in the Cognitive Radio environment is its large side lobes in the frequency domain, which is a result of single-symbol pulse duration. Filter Bank Multicarrier (FBMC) uses filters that have small side lobes to synthesize/analyze the sub-carriers so as to greatly alleviate the previous mentioned disadvantage. FMT is one FBMC technique. Although many hardware implementations have been explored during last few decades on OFDM, few FMT hardware implementation results, especially Hardware/Software Co-design, have been presented. This paper presents a HW/SW Co-design implementation result of FMT transceiver on the Altera DE4 board.