Phase sweeping transmit diversity with fading resistant constellations

The problem of slow fading in the forward link of a mobile radio system is addressed in this thesis. Transmit diversity at the base station is investigated as a solution to mitigating the long term impairment. A diversity system is proposed in which multiple antennas spaced far apart transmit simultaneously the same signal to the mobile terminal. The objective is to create artificial fast fading in an otherwise static environment. A channel coding scheme is devised which exploits the autocorrelation properties of the resulting fading envelope. By matching the frequency offset of the carriers to the interleaving depth of the channel coder, it is possible to realize antenna diversity gain at low mobile velocities and coding gain at high velocities. Simulations demonstrate the feasibility of increasing the diversity order of the forward link under slow fading conditions without having to maintain a condition of orthogonality between the multiple transmissions.