A wireless network is a computer network that uses radio signals at the physical layer. This results in a fundamentally different paradigms for wireless networking, as the links, the foundation of traditional networking, become a blurred notion. In terms of classification, there are single-hop and multi-hop as well as infrastructure-based and infrastructure-less wireless networks. Examples on the single hop side include cellular networks, wireless local area networks (e.g., 802.11), wireless personal area networks (e.g., Bluetooth), etc. On the multi-hop side, wireless mesh networks, wireless sensor networks and vehicular networks are popular examples.
Research topics in wireless networks stem from the wide variety of problems caused by the wireless nature of the links, including the always broadcast nature of the medium at the physical layer, followed by the inevitable interference and the resulting high error rates and reduce throughput. Additionally, localization problems specific to wireless devices are still confounding the community despite significant research efforts in the past decades.
Recently, significant increase in wireless data demands for a variety of applications also prompted the need for significant research toward efficient spectrum usage - many different solutions exist to increase this efficiency, but none come even close to meeting the ever increasing demand. The future of 5G wireless systems and high-speed WiFi technologies also brings new applications for content sharing, online social networks, real-time gaming, and intelligent transportation systems.