This paper explains the advantages of using a method for waveform shaping in COFDM. It is shown that such data shaping decreases the side lobes of the transmitted signal and minimizes the need for guard band between OFDM systems. Classical OFDM systems based on DFT make use of a guard interval in order t o improve the performance in multipath fading channels. A part of the loss due to the power transmitted during the guard interval can be compensated efficiently by the waveform shaping which is proposed. In the presence of both AWGN and multipath fading the bit error performance of the proposed system and the classical COFDM systems are compared.

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This paper intends to investigate a new receiving architecture able to jointly get both cancellation of cross-polar interference and combination of space diversity signals, in frequency reuse digital radio systems.It consists in a couple of linear transversal filters for each polarization which performs base-band fully digital signals processing, based on a minimum mean square error (MMSE) criterion. Performance is evaluated by analytical ineans and computer simulations, based on a software developed in CSELT.In spite of its simplicity with respect to a separate approach to cancelling and combining, it shows high performance in presence of both selective fading and cross polar interference. These characteristics make the structure suitable for effective use in the future radio links.