A high-speed local area network using spread-spectrum code-division-multiple-access techniques

A high-speed local area network that uses a bus architecture and spread spectrum techniques to overcome the problems of contention in a system with distributed control is described. Each node uses a pseudo-random binary code to modulate the data to be transmitted, effectively `spreading¿ the bandwidth of the signal, and may transmit independently without first sensing the media. Interference between simultaneous transmissions is avoided by the careful selection of the codes used. The paper presents a technical description of the system developed and compares its performance with other bus networks. The choice of codes to be used, and their effect on the maximum number of nodes allowed and the data rate is discussed. The performance of the system in a noisy environment is also considered.