Heterogeneous Wireless Networks: A Survey of Interworking Architectures

A vast majority of current wireless cellular networks are deployed using the homogeneous deployment scenario. The homogeneous cellular system is essentially a network base stations and user terminals with standards power level profiles and similar technical characteristics. All base stations in the network are similar and carefully planned for compatibility. This deployment scenario is complex, rigid, and expensive. Hence the need for a more flexible, cost-effective and ubiquitous deployment model capable of broadband delivery. This need informed the advent of heterogeneous networks, which allow for the deployment of non-homogeneous base stations, with the attendant advantage of improved spectral efficiency per unit area. One of the most important features of next generation networks is the roaming possibility of end user equipments across different access networks. The Session Initiation Protocol (SIP) makes this experience achievable, it also describes other different mobility management solutions and compares the suitability of SIP for roaming across General Packet Radio Service (GPRS), Universal Mobile Telecommunication System (UMTS) and wireless Local Area Networks (WLAN). We present in this paper an overview of the various wireless networking implementations vis-à-vis interworking architectures. The paper also discusses the three generic interworking architectures for WLAN 802.11 and 3GPP networks among others