Implementation Approaches Trade-Offs for WiMax OFDM Functions on Reconfigurable Platforms

This work investigates several approaches for implementing the OFDM functions of the fixed-WiMax standard on reconfigurable platforms. In the first phase, a custom RTL approach, using VHDL, is investigated. The approach shows the capability of a medium-size FPGA to accommodate the OFDM functions of a fixed-WiMax transceiver with only 50% occupation rate. In the second phase, a high-level approach based on the AccelDSP tool is used and compared to the custom RTL approach. The approach presents an easy flow to transfer MATLAB floating-point code into synthesizable cores. The AccelDSP approach shows an area overhead of 10%, while allowing early architectural exploration and accelerating the design time by a factor of two. However, the performance figure obtained is almost 1/4 of that obtained in the custom RTL approach. In the third phase, the Tensilica Xtensa configurable processor is targeted, which presents remarkable figures in terms of power, area, and design time. Comparing the three approaches indicates that the custom RTL approach has the lead in terms of performance. However, both the AccelDSP and the Tensilica Xtensa approaches show fast design time and early architectural exploration capability. In terms of power, the obtained estimation results show that the configurable Xtensa processor approach has the lead, where approximately the total power consumed is about 12--15 times less than those results obtained by the other two approaches.