THE UNIVERSITY OF BRISTOL has researched ways to transmit high quality video over wireless signals to handle the growing amount of mobile video traffic attributable to the rise of smartphone apps.
Published in the journal IEEE Transactions for Mobile Computing, the research was led by professor Andrew Nix and Dr Victoria Sgardoni from the University of Bristol's Communication Systems and Networks group.
"Video dominates internet traffic and by 2018 it is expected wired devices will account for 39 percent of internet protocol (IP) traffic, while WiFi and mobile devices will account for 61 percent of IP traffic," said the university.
The research looks to accommodate this and shows how videos can be better transmitted over wireless links such as WiFi and 4G.
Below is the University's cross-layer system simulator figure, which shows how cross-packet forward error correction (FEC) codes, such as Raptor codes, are applied at the application layer (AL) to allow the AL decoder to regenerate packets that were lost over the radio and network layers.
The proposed methodology takes into consideration the channel resources required to accommodate the Raptor encoding overheads.
"Simulation results show that packet loss is eliminated and the amount of radio resource required to transport video is reduced significantly," the University said.
Unicast systems based on the Automatic Repeat Request (ARQ) - an error-control method for data transmission - require up to 115.6 percent more channel resources compared to the researchers' proposed Raptor-aware LA system, without retransmissions, the University said.
The researchers said that the Raptor-aware LA system can enhance the link budget by up to 4dB, and thus increase radio coverage by up to 58 percent, and improve total good throughput by 46.7 percent compared to a traditional ARQ-based system.
The University believes that the research shows that this approach increases the transmission efficiency for unicast streaming of high-quality live video, while the video is delivered error-free, so it should relieve the "data crunch that is occurring in current and future networks".
The research is explained fully in a research paper that further explains how the adaptation of the radio layer depends on the parameters of the application layer coding, through Raptor-aware Link Adaptation and cross-layer optimisation. µ
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