The system and method of the present invention provide a protocol for a device (400) to announce that a previously reserved time-period or time-slot is not (completely) used and becomes available, so that other devices can transmit during the unused time. The system and method are especially intended...http://www.google.com.tw/patents/US7684428?utm_source=gb-gplus-share專利 US7684428 - System and method to free unused time-slots in a distributed MAC protocol
