Abstract: An apparatus and method for modeling, interacting with and testing market behavior has a system defining a virtual market that may be used to study and test algorithmic trading and market behavior at the microstructure level. The system may use real data and time sequences and features a trading mechanism implemented by a database server, an information center, client computers and a matching engine through which a live stream of orders is matched against a static historical stream of orders. In one embodiment, the system uses real servers on a real network with inherent latency.

Abstract: A multiple access communications system reuses a set of either N carrier frequencies or time slots in adjacent communications sites to provide more than N or T minimally cross-correlated frequency or time hopping communications channels respectively. A first set of communications channels is associated with a first of the communications sites. No two of the channels in the first set employ the same frequency or T time slots at the same time. A second set of communications channels is associated with a second of the adjacent communications sites. No two of the channels in the second set of channels employ the same one of the N carrier frequencies or T time slots at the same time. One or more sets of the minimally cross-correlated channels are further defined so that none of the channels in such sets employ the same frequency at the same time as more than a predetermined number of the channels in another of the sets of the minimally cross-correlated frequency-hopping communications channels.