In this paper we develop and analyze low-complexity approaches called incremental multiple-input multiple-output (IMIMO) for exploiting multiple antennas for reliable wireless communications. The proposed schemes leverage consecutive uses of a single transmit antenna combined with automatic repeat request (ARQ) feedback. Unlike multiple-input multiple-output (MIMO) communications without feedback, the schemes we propose do not require a space-time encoder or decoder because they only use one transmit antenna at a time. We compare the performance of IMIMO schemes with the corresponding MIMO system without feedback using outage probability and average long-term throughput as metrics for comparison. These comparisons show that for relatively low rates IMIMO schemes have better performance than the corresponding MIMO system without feedback. For higher rates, MIMO with higher complexity performs better up to a certain signal-to-noise ratio, but beyond this threshold IMIMO schemes again have better performance.

A very efficient and simple method for error concealment in image communication over packet loss networks is presented. The method involves embedding a combination of edge map and linear prediction residue of each image block as a robust watermark within the original image at the transmitter and using the extracted watermark along with spatial smoothing at the receiver in order to reconstruct the lost parts. The performance of the proposed scheme shows a 2 dB improvement over state of the art error concealment algorithms.