There is a growing need to find lasting solutions on how to deal with security issues involving with wireless networks, in order to make them as secure as possible. The growth of the Internet has been an explosive since inception, and this has lead to a great increase in the number of portable/mobile computing and communication devices such as notebook computers and mobile phones, in recent years. As manufacturers constantly improve on the features, and general capabilities of mobile devices, the Internet also continues to get bigger and to improve, even at a faster rate than these mobile devices.
In fact, the market for mobile computing and telecommunications is likely to overtake the market for fixed (conventional) computing and telecommunications, in the near future. This is because there has been a consistent growth in the demand for mobile devices for computing and telecommunications.  Without a doubt, wireless technology was has been a very relevant and vital breakthrough in the computer and telecommunications world, and the Wireless third generation (3G) network is proving to be increasingly beneficial to many users of various networks.
The main advantages of the 3G networks are that they provide a lot more interconnectivity and, a better and wider reach. Wireless Local Area Network (WLAN) has also been advantageous. Some of the advantages of WLAN include the use of Broadband service with low costs and wide-reaching technology. Therefore, integrating 3G wireless networks with wireless local area network was invented, naturally, so as to get the best of both words of3G wireless network and WLAN.  http://csrc. nist. gov/publications/nistpubs/800-48/NIST_SP_800-48.pdf
Background. WLAN and 3G are two key mobile/wireless technologies, which have been identified to have great potential in terms of value to the customer. While 3G is a standard that defines technology that can provide high bandwidth wireless access over a large area and supports various services such as roaming, WLAN is a disruptive technology that provides higher bandwidth within small areas. With WLAN getting integrated to 3G networks, there are several security threats that need to be considered.
These are threats that are unique to such an integrated network as well as threats due to the vulnerabilities inherent in each network. The 3rd Generation Partnership Program (3GPP) has defined the standards for the integrated WLAN-3G network. The organisation takes into consideration several security issues, as part of its standardisation efforts. However, there are still some gaps in the security that can adversely affect service delivery and vulnerability.
From the security point of view, the network architectures are defined for both Roaming and Non-Roaming inter-working scenario. Additional components are specified to the 3GPP network architecture to facilitate inter-working such as Packet Data Gateway (PDG) and WLAN Access Gateway (WAG). The inter-working is based on UMTS Authentication and Key Agreement (AKA) authentication method. This requires a user equipment to run the USIM application.
This means that WLAN user equipment is equipped with capability to use UICC smart cards. The inter-working mechanism enables a 3G mobile network subscriber to access WLAN networks operated by different service providers. This also supports roaming scenarios. Wireless local area network (WLAN) and 3-G devices enable users to carry their computers and communication devices around within their offices and homes, without having to handle any wires and without having to disconnect from the network when moving around.
There is greater flexibility with these devices, due to less wiring, thereby increasing overall efficiency, and also reduced wiring costs. For instance, networks that use Bluetooth technology can be used for synchronization of data with network systems, and enable the sharing between of computer applications between devices. With Bluetooth functionality, there is no need for printer cables and some other connection equipment for peripheral devices.