January 2012, Las Vegas, One of the big discussions at CES was the prevalence of 4G networks, and the hopeful availability of video conferencing. The promise of 4G networks with their high bandwidth potentials has brought a great deal of excitement to the marketplace. At the CES show, Alcatel was showing an LTE transceiver pair that could be located in public safety vehicles. The main point was the reduced size of the transmitters set with a mobile tower.

Videyo conferencing on Alcatel LTE network

The unit was transmitting about 100 feet in the demo, and the technical members in the booth indicated, if there was access to power, they new LTE kits would transmit functionally between 900m and 1Km of the optimal 2Km reach of the cellular technology. The product was shown using the Vidyo video conferencing system between a desktop computer and mobile device. The running system is shown in figure 1. A drawback of the whole configuration is the packet loss protocol issues with current video conferencing. While the network shows high bandwidth data in the transfer stream, it also has a very high packet resend requirement to complete a communication loop. Figure 2 shows not only the packet loss numbers, but also the reduction in actual throughput in the network when the RTP protocol is used for video traffic.

Alcatel LTE and video conference data transfer

An issue for the practical use of these networks and applications that are utilizing RTP, is the minimum bandwidth requirements. Figure 2 also shows the actual transfer bandwidth being used for the VGA level (considered HD) video conference. As most broadband services in the US for residential applications have low upload capabilities (typically 1/10 of the download speed, or near 100Kbps) it is not on the same path for upgrade as the download speeds. Figure 3 shows the estimated bandwidth requirements for simple HD (above 320i) video conferencing as recommended by multiple vendors at the show and highlighted in the Nvidia booth as a new GPU based activity.

video confernce bandwidth requirements

The realities of the LTE environment, the distance and data rates it supports and the prevalence of the RTP protocol in the use of conferencing leads one to believe that these technologies may not be universally available outside major metropolitan areas in the near future.