A Brief History of Kandou Bus

Kandou Bus uses a novel form of spatial coding to transmit data between wired chips. The main idea is to introduce correlations between the signals sent on the interface, and choose the correlations judiciously to lower the power consumption, increase the speed, and lower the footprint. It is a generalization of differential signaling (which sends correlated signals on two wires). The company is a spinoff of Dr. Shokrollahi’s lab at the Swiss Federal Technical Institute in Lausanne.

The company originated in a casual conversation about using channel coding to improve the throughput of DSL lines. The conversation was abound with “differential signals over twisted pairs.” “What is differential signaling?” asked Dr. Shokrollahi whose background is in mathematics, algorithm design, and channel coding than rather than in electronics. Once he heard what it was, he asked “so, how many wires do you use to send, say, 10 bits?” When he heard that the solution would be to use one pair for every bit to send, he immediately saw the inefficiency of the system and used his coding background to come up with a new solution in which signals were “smeared” across multiple wires. Thus, the idea of “Chord Signaling” and the company Kandou Bus was born! The name of the company is the Farsi word for beehive. Just as in a beehive where the hive’s output relies on collaboration between the bees, the superior properties of chord signaling are obtained through collaboration between the signals on the wires.

Over the course of the following 10 months, Dr. Shokrollahi assembled a team consisting of electronics and communication engineers and developed the new theory of chord signaling, and produced the first proofs of concept. The team focused on a typical mobile memory link, and taped out the very first instantiation of chord signaling capable of transmitting and receiving signals at 6.25 Gbps per wire over 10 cm of PCB trace. In this instantiation 8 bits were dispersed over 8 wires, but in a way as to make the transmission as resistant as differential signaling (which would require 16 wires). Soon after the fab out of that prototype, the team started developing a second full transceiver capable of transmitting and receiving up to 16 Gbps per wire over a challenging channel. The results of this chip have been presented at ISSCC 2014.

In the meantime, Kandou Bus has secured a Series A financing round, and has developed a product strategy to attack applications as varied as high speed networking, memory links, short chip-to-chip links via interposers, and low-power, high speed communication over TSV’s. The company is also active in the OIF-CEI and IEEE-802.3bj standards bodies and is proposing one of its technologies for solutions to the interconnect problems of various industries.

About Kandou Bus S.A.
Headquartered in Lausanne, Switzerland and founded in 2011, Kandou Bus is an innovative interface technology company specializing in the the invention, design, license and implementation of unmatched chip-to-chip link solutions. Kandou’s Chord™ technology lowers power consumption and improves overall performance of semiconductors, unlocking new capabilities in electronic devices and systems. http://www.kandou.com.