Increasing real world bandwidth - Coded TCP

One of the biggest problems with wireless transmission is loss of packets due to a number of factors that range from interference, obstructions, movement etc.. The way current transmission protocols deal with lost packets is to resend those missing packets before the recipient gets the intended data, and lead to lower throughput.

A team of researchers, headed by a team at MIT has developed a new technique where they have replaced packets with algebraic equations that describe blocks of packets. If the receiver loses part of the message, the receiver can solve the equation resulting in the complete packet block, thus negating the need for the transmitter to have to re-send packets, and because the equations are linear and simple, this will not have a significant impact on the processor of the receiving device. The beauty of this technique is that it can be applied to any existing IP transmission technology, although wireless will reap the main benefits as wired network don't experience loss of this kind.

Testing by the MIT team have shown incredible results. In MIT Campus, where the average loss is around 2%, WIFI was averaging 1Mbps, using the coded TCP method increased this to 16Mbps. On a fast moving train, where the average loss in packets is around 5%, the connection speed jumped from 0.5Mbps to 13.5Mbps. So the improvement is in order of a magnitude, not just small percentage gains!

It has to be understood that this will not improve matters where there is no loss, so you will not get a 3Gbps speed from a 300Mbps connection. It will be in the areas where loss of packets are most apparent that this will have the biggest gains.

For us, we see this being applied to point to point wireless bridges where there are to the Fresnel zone, or a long distance link where loss of signal strength has degraded to the point where the throughput speed will have dropped below required specs. As long as there is a signal connection, then we see the ability for high real world data rates can be achieved with much higher success rates.

Other application will be the mobile sector, which has higher loss rates due to client devices moving around, being inside buildings. Internal Wireless LAN networks will see gains also, with higher throughputs being sustained where loss would be contributed to obstructions by walls floors, and people in general.

The technology is being licenced to a number of companies, so we should start to see this being implemented in future tech very soon!

Link: Modelling Network Coded TCP