With rapid growth of digital communication in recent years, the need for high speed data transmission is increased. Moreover, future wireless systems are expected to support a wide range of services which includes video, data and voice. OFDM is a promising candidate for achieving high data rates in mobile environment, due to its resistance to ISI, which is a common problem found in high speed data communication. In OFDM, modulation may be differential or coherent. When using differential modulation there is no need for a channel estimate but its performance is inferior to the coherent system. Coherent modulation requires the channel estimation which gives better performance but with relatively more complex receiver structure. Training Symbol Assisted Modulation is used to achieve reliable channel estimates by transmitting Training along with data symbols. In this thesis, Shazib Naveed has analyzed different channel estimation patterns in terms of BER and propose a new scheme for transmitting Training symbols in wireless OFDM systems. Author has also proposed an adaptive scheme of channel estimation in wireless OFDM systems, which track the multi-path fading channel.