Experimental evaluation of secondary NC-OFDM transceiver for coexistence with primary transmitter

RF Spectrum scarcity inhibits development of newer wireless communication technologies in a big way. With the current spectrum policies, there is heavy under utilization of available spectrum. This calls for more efficient spectrum allocation. One of the solutions to the problem is dynamic spectrum allocation algorithms. This can be achieved with the use of Cognitive Radio Technology. Cognitive radios allow for dynamic changing of transmission parameters depending on the environment and available spectrum bands. The definition of Cognitive radios terms it an intelligent radio which alters its transmission/reception parameters in accordance with the radio environment and the network state to utilize spectrum efficiently. Cognitive radio technology allows for use of unlicensed secondary devices to utilize spectrum unused by licensed primary devices. The secondary devices can utilize the spectrum and transmit in bands not used by the primary devices in order to avoid any detrimental interference to the licensed primary users. This calls for stringent control of the secondary transceiver. In this thesis, we focus on designing an LTE standard based Non Contiguous Orthogonal Frequency Division Multiplexing Secondary Transceiver. The major focus has been on hardware design of the secondary LTE transceiver and a system level implementation on a National Instruments based Real Time Embedded Controller platform, with relevant design blocks developed on FPGA hardware for efficient implementation. The various functionalities and tradeoffs involving hardware design of a transceiver have been studied. In addition, the effect of employing FPGA based design with a view of resource utilization and latency of the whole transceiver system, has been considered. Dynamic Spectrum Access setup was evaluated with the NI based secondary transceiver platform by evaluating the secondary receiver's performance in the presence of a primary user in the notch. This allowed for efficient utilization of spectrum for the unlicensed secondary user without causing detrimental interference to the primary user's signal.M.S.Includes bibliographical referencesby Abhishek Bindiganavil