Among various types of network architectures, the mobile ad hoc network (MANET) and the wireless sensor network (WSN) are two of the most attractive wireless networks. One critical issue for almost all kinds of wireless devices supported by battery powers is power saving (PS)}. Without power, any wireless device will become useless. Battery power is a limited resource. Hence, how to lengthen the lifetime of batteries is an important issue, especially for MANETs and WSNs, those are supported by batteries only. Hence, we design PS protocols for MANET and regular WSNs.