Radio Frequency Spectrum

Frequency Hopping, Spread Spectrum Technology

Each microcell radio uses many frequency-hopping channels in the 900-MHz and 2.4-GHz bands and uses a randomly selected hopping sequence, enabling multiple subscribers to use the network simultaneously. This technique makes more efficient use of a given band of frequencies because many more radio transmissions can take place simultaneously without interfering with one another. It is also extremely robust and will easily cut through potential interference.

Packet-Switched Networking

For efficient transfer of data over radio waves, the Ricochet network transmits data by segmenting and routing information in discrete data units called packets. Each packet has its own control information for routing, sequencing, and error checking. Packets are routed from radio to radio across the wireless network. This means that multiple communications between radios can occur simultaneously. With packet switching, a communications channel can be shared by multiple users, with each using the channel only for the time required to transmit a single packet typically no more than 20 milliseconds. In conjunction with frequency hopping, packet switching provides the Ricochet network with a tremendous amount of network capacity.

The basic structure of...