Issues in Mobility Management in 4G Networks
Researchers and vendors are expressing a growing interest in 4G wireless networks that
support global roaming across multiple wireless and mobile networks—for example, from a
cellular network to a satellite-based network to a high-bandwidth wireless LAN. The 4G
mobile system is an all IP-based network and provides the user access to different radio
access technologies. In this environment, roaming is seamless and users are always
connected to the best network.
This paper aims to provide an insight into the issues related to Mobility Management in 4G
networks, and focuses on the enhancements required to make IPv6 the underlying protocol
Traditional phone networks (2G cellular networks) such as GSM, used mainly for voice
transmission, are essentially circuit-switched. 2.5G networks, such as GPRS, are an
extension of 2G networks, in that they use circuit switching for voice and packet
switching for data transmission. Circuit switched technology requires that the user be
billed by airtime rather than the amount of data transmitted since that bandwidth is
reserved for the user. Packet switched technology utilizes bandwidth much more
efficiently, allowing each user’s packets to compete for available bandwidth, and billing
users for the amount of data transmitted. Thus a move towards using packet-switched,
and therefore IP networks, is natural.
3G networks were proposed to eliminate many problems faced by 2G and 2.5G networks,
like low speeds and incompatible technologies (TDMA/CDMA) in different countries.
Expectations for 3G included increased bandwidth: 128 Kbps in a car, and 2 Mbps in
fixed applications. In theory, 3G would work over North American as well as European
and Asian wireless air interfaces. In reality, the outlook for 3G is neither clear nor certain.
Part of the problem is that network providers in Europe and North America currently
maintain separate standards’ bodies (3GPP for Europe and Asia; 3GPP2 for North
America). The standards’ bodies mirror differences in air interface technologies. In
addition there are financial questions as well that cast a doubt over 3G’s desirability.
There is a concern that in many countries, 3G will never be deployed. This concern is
grounded, in part, in the growing attraction of 4G wireless technologies.
A 4G or 4th generation network is the name given to an IP-based mobile system that
provides access through a collection of radio interfaces . A 4G network promises
seamless roaming/handover and best connected service, combining multiple radio access
interfaces (such as HIPERLAN, WLAN, Bluetooth, GPRS) into a single network that
subscribers may use. With this feature, users will have access to different services,
increased coverage, the convenience of a single device, one bill with reduced total access
cost, and more reliable wireless access even with the failure or loss of one or more