Design and implementation of an OFDMA-TDD physical layer for WiMAX applications

Abstract

This work describes the design, implementation, and performance evaluation of an orthogonal frequency division multiple access (OFDMA) time-division duplexing (TDD) physical layer (PHY) compliant with the worldwide interoperability for microwave access (WiMAX) standard using a costeffective software-defined radio (SDR) platform containing field programmable gate array (FPGA) and digital signal processor (DSP) modules. We show that the proposed SDR architecture is capable of supporting the wide variety of configuration options described in the WiMAX standard while fulfilling the stringent requirements of WiMAX OFDMA TDD PHYs. The architecture allows for the implementation of all TDD functionalities in the downlink and the uplink at both the base station and the mobile station. The proposed design is shown to efficiently use the available FPGA and DSP resources. We also carried out specific experiments that take into account the frame and the downlink map messages detection over ITU-R wireless channel models to illustrate the performance of the proposed design. Finally, we discuss the utilization of the proposed hardware architecture to implement the wirelessMAN-advanced air interface.

A Real-Time Implementation of the Mobile WiMAX ARQ and Physical Layer

“…Additionally, the paper also includes a very rich performance evaluation of the real-time implementations of both physical and MAC layers based on representative figures of merit such as bit and frame error rates or throughput and considering the reference scenarios defined by the WiMAX Forum, including both static and mobile scenarios. A description of an implementation of the physical layer can be found in a previous work [8] as well as results for synchronization and other physical-level metrics. The present work extends that architecture and shows new results which can be obtained with the new implemented features.…”

Experimental evaluation of the WiMAX downlink physical layer in high-mobility scenarios

“…This structure leads to a threefold repetition in the time domain, which can be exploited for frame detection and time and fractional carrier frequency offset (CFO) estimation. Integer frequency shifts are corrected after the DFT by performing a cross-correlation between the differential sequences of the transmitted and received preamble pilot sequences [20,21].…”