A few high power tones used for synchronization and/or other purposes are transmitted in a FDM system during a period of time into a region, e.g., sector of a cell, e.g., a symbol transmission time period. During normal data transmission symbol periods signals are transmitted using at least 10 tones,...http://www.google.com/patents/US20040109432?utm_source=gb-gplus-sharePatent US20040109432 - Beacon signaling in a wireless system
