Design and implementation of Polyphase based FHSS modulator using GNU Radio and SDR

Wireless communication is the fastest-growing sector in the communication industry. The nature of wirelessly transmitted signals makes them prone to eavesdropping and jamming. The intercepting of these signals leads to the leaking of sensitive data and poses a threat. As a result, the security and dependability of wireless systems are jeopardized. Spread Spectrum enables the signal to be spread out over a larger bandwidth before transmission. Frequency Hopping Spread Spectrum (FHSS) prevents the transmitted signal from eavesdropping by hopping onto different carrier frequencies. FHSS has been prominently used in military applications and wireless standards such as Bluetooth. The higher the hopping bandwidth, the more immune is the system to interferences. A digital FHSS system based on Polyphase channelizers is designed using Software Defined Radios (SDR). Polyphase channelizers utilize N-point Inverse Fast Fourier Transform (IFFT) for inverse Fourier transformation, the computational efficiency of using IFFT is discussed. The SDR approach is used to implement Frequency Hopping Spread Spectrum as they offer faster prototyping and reliability. Using GNU Radio and Universal Software Radio Peripheral, a digital-based Frequency Hopping Spread Spectrum modulator using Polyphase channelizers is designed and implemented in real time.