The IEEE 802.15.4 MAC protocol supports the beacon- enabled working mode through periodically broadcasting superframe beacons. The beacons play the key role in channel access synchronization and are used to distribute channel information such as the length of contention avoidance period, etc. However, some information such as pending addresses and guarantee time slot allocation are also broadcasted, which can cause substantial energy waste in a personal area network, as they are not needed by all members. To overcome this inefficiency, this paper proposes a channel reservation scheme to multicast this information. Analysis shows that our proposed method can achieve energy savings with very loose conditions.