Wireless network has become increasingly popular in the past few decades, particularly within the 1990’s when they are being adapted to enable mobility and wireless devices become popular. In the near future, a pervasive computing environment can be expected based on the recent progresses and advances in computing and communication technologies. Next generation of mobile communications will include both prestigious infrastructured wireless networks and novel infrastructure less mobile ad hoc networks (MANETs). A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. This paper describes the fundamental problems of ad hoc networking by giving it related research background including the concept, features, and its applications in future wireless network especially in the hostile military environment. By combining two hottest wireless network topics, 4G (the fourth generation of cellular communication systems) and MANET, we explore potentials as well as foreseeable challenges to the wireless communications in the future battlefield. Special attention is paid on network layer routing strategy of MANET and key research issues include new X-cast routing algorithms, security & reliability schemes, QoS model, and mechanisms for interworking with outside IP networks.