In this thesis work, we implement the GMSK modem algorithm for wireless digital communication in real-time using a Motorola 56002 DSP and design the VHDL module for the modem.
In order to implement the GMSK algorithm, we first simulate it with C language. We obtain the performance of both coherent and noncoherent receiver algorithms in computer simulation. In the simulation, we consider two types of noncoherent receiver algorithms : one bit and two bit differential detection, and two kinds of timing recovery algorithms. All simulations are done under an AWGN and fading channel condition.
Based on the computer simulation results, assembly language coding is done for real-time implementation of the GMSK algorithm. The resulting DSP modem is capable of full-duplex data transmission up to 300 bits/s.
All the building blocks of the VHDL module of the GMSK modem are designed according to the structural model for logic synthesis and simulated with a VHDL simulator. The VHDL module consists of a memory interface block, a transmitter block, a receiver block, a control block and an accumulator block for filters. The module is designed in the pipeline structure.
