ADAPTIVE MULTIMODE MULTIBAND NARROWBAND SDR WAVEFORM BASED ON CONTINUOUS PHASE MODULATION (CPM)

Abstract

A Software Defined Radio (SDR) is a radio transceiver that is well defined in software and whose physical layer conduct, parameters, and protocols can be fundamentally modified through software as a waveform. This approach will increase the flexibility of the device by changing its operating parameters while not having an upgrade or exchange of any hardware parts. Thus, SDR provides a platform capable of supporting distinctive waveforms. The main distinction lies in the focus of implementation, a few waveforms are designed which accomplish higher data rate, whereas others prioritize range and transmission capacity. It is recognized that strategic military radios need wideband and narrowband waveforms for fulfilling most of the military requirements. Wideband networking waveform (WBNW) ensures a high data rate; this lowers the range whereas for applications requiring long-range communication, narrowband networking waveform (NBNW) tends to be a dominant choice. Modern strategic VHF communication frameworks require increasing throughputs to support a wide variety of applications for military, commercial, and civilian applications. It requires a combination of spectral efficiency and better ber performance. To meet the heterogeneous requirement of future wireless networks, an adaptive multimode multi-band narrowband waveform for software-defined radio based on Continuous Phase Modulation (CPM) is presented in this thesis. Due to higher spectral efficiency and constant envelop property provided by CPM, we show that the proposed waveform attains higher throughput by shifting towards multiple bandwidths and for the appropriate choice of alphabet size M, pulse length L and modulation index, h. In the next step a novel algorithm for link adaptation scheme for packet-based Narrowband networking SDR waveform is proposed. To reduce the packet re-transmissions overhead, the configurable system parameters need to be changed dynamically according to the channel conditions ensuring specific Quality of Service (QoS) requirements and reduces the computational complexity/power consumption by restricting the throughput to the required value. At the end, the BER performance of proposed multimode multiband waveform for CPM is evaluated in AWGN and Stanford University Interim channel (SUI) channel model.