All-IP Wireless Networking

The proliferation of competing wireless technologies has led the wireless communications industry
to move toward mobile networks that follow an all-Internet protocol. Voice-over-IP (VoIP) telephone
communications and videoconferencing have already become a reality, proving that all-IP technology
can produce successful applications. It will take several years to finalize standards for all-IP networks,
and many more for these networks to be deployed with great density. Therefore, there will be a
long migration from current circuit-based networks and services to the all-IP environment [487].
The Internet Protocol, or IP, already a universal network-layer protocol for packet networks, is
rapidly becoming a promising universal network-layer protocol for all wireless systems. The reason
is that an IP terminal with multimode radio or software radio can possibly roam between different
wireless systems if they all support IP as a common network layer. Unlike today’s Radio Access
Networks (RANs) which are mostly proprietary, IP provides an open interface (and promotes an
open market). Distributed (autonomous) IP-based base stations will make the RANs more robust,
scalable, and cost effective. In addition, deploying IP to wireless networks will enable IP-based
applications to run over wireless networks, which will change mobile communications significantly
[490]. In all-IP settings, mobile and wireless networks will be integrated together under an all-IP
core network to support global roaming and services. Issues such as mobile security, quality-ofservice
(QoS), and mobility management are now being investigated to ensure that all-IP designs
will meet the needs of the users of the new technology. For mobile ad hoc and sensor networks,
critical issues include power saving, routing, sensing, media access control (MAC), and integration
with other mobile networks [488]. Other challenges to realizing distributed all-IP wireless networks
include technology independent IP signaling on all wireless and wired networks, IP-based mobility
management supporting fast handoffs and universal roaming, real-time and non-real-time applications
with guaranteed QoS, design, and realization of IP-based base station, authentication, authorization,
and accounting (AAA), and smooth and seamless interworking with today’s public switched telephone
networks (PSTN) and first-generation/second-generation (1G/2G) wireless telephony [490]. Running
an IP-based telephony system is much cheaper than running a traditional circuit-switch based system.
VoIP has become the most important and the best accepted IP-based service in wireless networks.
Naturally, the QoS is critical to VoIP and other real-time services, like video conferencing. Figure 5.1
shows the variety of services that can be interconnected using all-IP technology. At the bottom of
the figure are the users of voice, data, and VoIP. In the middle are various access networks and
technologies used to access public telecommunication services, and at the top are examples of the
public telecommunication services: PSTN and IP networks.