Hardware implementation of Frequency Domain Link Adaptation for OFDMA based systems

Abstract

Frequency Domain Link Adaptation (FDLA) has been accepted as a promising technique to improve the spectral efficiency in Orthogonal Frequency Division Multiple Access (OFDMA) systems such as Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WIMAX). FDLA exploits the frequency domain channel variation by using adaptive bit and power loading scheme in frequency domain. In this paper, we propose a hardware efficient architecture of adaptive bit loading scheme and implement the same in FPGA. It is shown that the FPGA design provides power efficiency and lower latency implementation. The design is shown to be flexible and reconfigurable and is compatible with multiple standards with different configurations. In this work, two different FDLA algorithms are implemented. This design is implemented in Wireless Open Access Research Platform (WARP) which has virtex-4 FPGA in its core for processing. The design is tested for its over the air performance by integrating it with FPGA based MIMO-OFDMA testbed, developed on the WARP platform. Real time over the air performance results are presented for uncoded systems.