Two new coding techniques for diversity communication systems

In classical diversity techniques used in combating fading and in spread-spectrum systems, the same information is transmitted over m ⩾2 channels, and the overall error probability is reduced by a suitable combination of the m received signals. Two techniques are proposed whereby the signals transmitted over the m channels corresponding to a given message can be encoded through a suitable error-correcting coding operation, thereby enhancing reductions in the receiver-side bit error probability with respect to classical diversity techniques. Gains have also been achieved by introducing a soft decoding operation at the receiver side and, in spread-spectrum systems, by adding side information. Applications to fading-affected communication systems and spread-spectrum systems are discussed