Frame Fountain: Coding and Decoding MAC Frames

Abstract To address the large latency and degraded network throughput due to the retransmission triggered by frame loss in high speed wireless networks, this paper proposes a solution called Frame Fountain that encodes and decodes data frames in the MAC layer. This solution intelligently encodes a number of redundant frames from original frames upon link loss rate so that a receiver can effectively recover lost original frames without significant retransmissions. Meanwhile, various probability distributions are investigated to find an optimal one as the degree distribution adopted by this coding solution. Extensive experiments show that, working with a degree distribution improved upon robust Soliton distribution, Frame Fountain can recover most of original frames with large probability

Cooperative Binary Relaying and Combining For Multi-Hop Wireless Communication

Cooperative communication can achieve diversity gain and increase the channel capacity. This paper proposes a novel cooperative scheme called Cooperative Binary Relaying and Combining (CBRC) for multi-hop wireless networking systems where the nodes cooperatively demodulate high-order modulated signal symbols with low-order robust modulations. Low-order demodulation schemes make partial decision at each relay node and avoid propagating the errors that can result from high-order demodulation schemes in conventional cooperative relaying. Therefore, CBRC supports high bit rate transmission at high-order modulations over low SNR links. Extensive simulations are conducted to evaluate the bit error rate performance of CBRC and conventional cooperative strategies. The results show that CBRC can significantly improve the performance. © 2012 IEEE

Analytical and Comparative Investigation of 60 GHz Wireless Channels

This work analytically studies the channel characteristics of 60 GHz wireless communication, particularly from five aspects: path loss, multi-path fading, spatial diversity, peak-to-average power ratio of OFDM and clear channel assessment. This investigation is performed in comparison to the 2.4 GHz wireless system. The observed merits of the 60 GHz wireless channels include: 1) the support of packing a large number of antennas at a transceiver to exploit spatial diversity, 2) light effect from multi-path fading due to its small average fade duration and 3) a fast detection of signals in carrier sense to achieve clear channel assessment. Its weaknesses consists of: 1) large path losses that lead to short communication ranges and 2) high peak-to-average power ratio that increases the cost and complexity in implementing OFDM in transceivers

Real Time Video Stitching by Exploring Temporal and Spatial Features

Although image stitching has been investigated for years, realtime video stitching still lacks of e cient methods to meet the required frame rate for satisfactory human vision experience. This work pro- poses e cient video stitching solutions by exploiting both temporal and spatial features among video frames. As a result, the stitching speed is signi cantly improved with two techniques by exploiting: (1) the dimmension of distance (spatial) by focusing only on the region of frame overlap and (2) the dimmension of time (tempo- ral) by reusing homography information across multiple frames. Based on these two techniques, this paper presents three solutions to determine submiages for rapid stitching the video frames from side-by-side cameras. This work implements these solutions into a video stitcher. The evaluation over video streams shows that the proposed solutions can stitch the video at 6.5 frames per second (fps) in contrast to 1.5 fps in conventional imaging stitching approaches, which is over 400% improvement on stitching speed performance, but at the cost of a marginal drop in accuracy