A network is described. In one embodiment, the network comprises multiple subscriber units to communicate with the base station using an orthogonal frequency-division multiple-access (OFDMA) protocol, and a base station. The base-station includes a memory unit to store broadband spatial signature vectors...http://www.google.de/patents/US6870808?utm_source=gb-gplus-sharePatent US6870808 - Channel allocation in broadband orthogonal frequency-division multiple-access/space-division multiple-access networks
