The objective of this thesis is to introduce (design with mathematics), simulate and analyze "The selectively imposed training symbols over data symbols carried by pilot carriers and corresponding Channel Estimation (CE)" based Coded OFDM (COFDM)/COFDMA system for frame based transmissions in order to find out more optimized solutions for Mobile Wireless Broadband Access (MWBA) in terms of spectrum utilization and information transmission efficiency. As it is necessary to deal with a system here, one has to think about all the aspects of the system. The most important contribution in the thesis is the own approach of dealing with the system with own combination of stages and introduction to innovations in pilot transmissions and corresponding CE. The work is partially extended to adaptive COFDM system because for the same pilot setting, if other parameters are varied, the performance differs. The performance of the whole system is dependent upon allocated channel bandwidth, cyclic prefix, vehicular speed, modulation scheme, FFT points, number of subcarriers etc. Channel model selection is also a crucial issue here.