Optimisation of Gaussian Minimum Shift Keying Modem using Coordinate Rotation Digital Computer Algorithm

Abstract

newline The spectral and power efficiencies can be achieved by using the popular Gaussian newlineMinimum Shift Keying (GMSK) modulation technique which gained the importance to newlineuse in most of the cellular systems. To improve the hardware complexity issues and newlinespectral efficiency problems, Optimized Coordinate Rotation Digital Computer newline(CORDIC) based GMSK is proposed which can resolve problems with better newlineperformance and use in real-time applications. newlineThe prime aim of research work is to design an efficient, optimized and cost-effective newlineGMSK transceiver system which improves the system performance and utilizes fewer newlinehardware resources. Hence, the proposed GMSK transceiver system is designed using newlinePipelined CORDIC / Optimized CORDIC algorithms. The GMSK transceiver hardware newlinearchitecture mainly contains Non-Return-Zero encoder and decoder, Data Integrator newlinemodule, and Data Differentiator module, Gaussian Filter, Frequency Modulator (FM) and newlineFM demodulation using CORDIC modules and Digital Frequency synthesizer (DFS). newlineThe Pipelined/ Optimized CORDIC module generates the cosine and sine values in the newlineform of In-phase (I) and Quadrature-phase (Q) generation. The DFS generates the sine newlineand cosine waveform for IQ modulation. The CORDIC plays a significant role in the newlineGMSK transceiver system. Each of these modules are designed using Verilog-HDL code, newlinesynthesized on different Field Programmable Gate Array (FPGA) devices and simulated newlineon a Modelsim and performance is evaluated on a target specific FPGA device. The newlinegeneration of I and Q signals consumes more resources and processing time in the GMSK newlinetransceiver. Hence, optimization of CORDIC is necessary to resolve these issues and newlineimprove the system performance. newlineIn the first part of the research work, the need and importance of data on GMSK modem newlineis analyzed. An intensive research review on GMSK modem is carried out. The research newlinegap driven to investigational research on FPGA implementation of CORDIC based newlineGMSK modem for data transmission. Hence the research objectives are addressed to newlineFPGA implementation of GMSK modem using CORDIC algorithm. newlineThe second part of the research work is CORDIC based GMSK modem design for data newlinetransmission and its FPGA implementation. The core of the work involved in novel newlineimplementation of Optimal Gaussian Filter, CORDIC algorithm for I and Q generation newlineii newlineand novel flexible multiplier. FPGA implementation of GMSK modem using general newlineCORDIC architecture individually as well as its integrated is analyzed and results are newlinepresented. The results indicated improvement in proposed design parameters such as area newlineand power. newlineIn third part of the research work, FPGA implementation of GMSK transceiver with newlinePipelined CORDIC architecture is described. The design of GMSK modules along with newlinePipelined architecture is simulated using Modelsim and performance is evaluated. newlineThe fourth part of the research work is to address the novel architecture; Optimized newlineCORDIC architecture based GMSK transceiver system and its FPGA implementation for newlinean improved throughput and design parameters such as area and power. newlineThe optimization of GMSK modem using CORDIC algorithm is addressed with Single newlineCarrier GMSK modem with CORDIC algorithm, pipelined CORDIC algorithm based newlineGMSK as well as optimized CORDIC algorithm based GMSK. The results indicated that, newlinethe improvement in hardware resources leading to area, power and frequency of newlineoperation