Potential Scenarios and Drivers of the 4G Evolution

In a world of increasing technological needs, the mobile Internet can play a significant role, meeting user's capacity and connectivity needs. There is a good deal of research around the 4G concept, where vendors and operators are trying to define it based on their preferred technology and strategic planning.

At the end of 2007, the global mobile subscribers reached 3 billion, with GSM based users accounting for over 2 billion. Several research reports have been predicting that WiMAX will be commercially deployed by 2009 and LTE (Long Term Evolution) by 2011. However, the debate on the standards for 4G continues and is a major concern. International Telecommunications Union (ITU), Institute of Electrical and Electronics Engineers (IEEE) and other similar associations and committees are working on securing a smooth transition to the new technology.

The 4G evolution as described in Figure 1, started in early 1990s transitioning into different stages, such 3.5G and 3.75G, ending to the 4G, meeting the market needs in most of the cases. The most recent transition that is expected is the migration from High Speed Packet Access (HSPA) to the 4G standard, which could be the WiMAX or the LTE or the combination of both.

 
Figure 1: 4G evolution into convergence 

In order to describe the market needs and behavior towards the 4G evolution, it deemed necessary to assess several countries' current readiness to deploy the 4G technology. Supporting the opinion that the LTE evolution will be the winning 4G, we have defined several metrics from different perspectives such as technology, business, and consumer spending to rank each market's 4G readiness in 16 countries. Our main objective is to use a ranking approach to shed light into the factors that are driving countries' progress in deployment of 4G, be able to estimate the deployment speed, and create future scenarios. We create three groups of countries ‘established leaders’, ‘rapid adopters’ and ‘late entrants’. We also want to be able to compare 4G readiness results with existing similar studies for the same countries to provide observations and derive useful conclusions.

RESEARCH REQUIRED FOR 4G WIRELESS APPLICATIONS

The common research areas which are evolving for 4G of wireless communication systems are:

1. New decoding algorithms for turbo codes for wireless channels.
2. New coding/modulation techniques for reducing the peak-to-mean envelope ratio, maximizing the data rate and providing large coding gain.
3. New approaches to jointly designing modulation techniques, and power amplifiers to simultaneously obtain high power added efficiency along with bandwidth efficiency.
4. New demodulation / decoding techniques to simultaneously combat the near-far problem and do channel decoding in multi-rate DS-CDMA (Direct Sequence Code Division Multiple Access) systems.
5. Communication problems unique to high frequency systems (e.g., channel estimation).
6. Joint channel estimation and decoding/demodulation algorithms.
7. Multiple-access techniques for multi-rate systems with variable quality of service requirements.
8. Space-time coding for systems with multiple antennas.
9. Analog decoding techniques for high speed, low power systems.
10. Ultra wideband systems and hardware design. (xi) Research in methodologies for an integrated approach to wireless communications (device layer: e.g., power and low noise amplifiers, mixers, filters; physical layer: coding, modulation; medium access layer: CDMA/FDMA/TDMA; data link layer: hybrid ARQ (Automatic Repeat Request); network layer: routing protocols).

Current Research in Security for 4G

Yoshihiro Ohba has divided security in 4G into Access Network security and Core Network security. For the access network security, a peer authentication mechanism across different link-layer technologies can be utilized for roaming. EAP (Extensible Authentication Protocol) is one such example of technology that can be recognized as unified PEA mechanism. For the core access network, security associations need be established between between a mobile and a middle box in the core network for different protocols such as Mobile IPv4/v6, SIP, Mobile IPv4/v6, SIP, IPsec IPsec, 802.21 MIH (Media, 802.21 MIH (Media-Independent Independent Handover) protocol. A single sign-on mechanism based on network access long term credentials may be needed to bootstrap security associations for different protocols.

Yu Zheng et al. have proposed trusted computing based security architecture for 4G networks: The security framework based on Trusted Mobile Platform (TMP) and PKI is mentioned to provide a considerable robust platform for user's access to sensitive service and data in the scenario of 4G systems. Over this framework, with the combination of password and biometric identification (BI) as well as public key-based identification, an efficient hybrid authentication and key agreement (HAKA) scheme is presented to resist the possible attacks, particularly the attacks on/from ME. Compared with 3G architecture and other security schemes for 4G mobile networks, architecture and corresponding HAKA has been mentioned to be more secure, scalable and convenient to support globe mobility and capable of being employed to handle the complicated security issues in 4G mobile networks.

Security Requirements for 4G & wireless security

Security is an important essential requirement for 4G:

1. Security requirements on ME (Mobile Equipment)/USIM (Universal Subscriber Identity Module):
   1. Protection of integrity of the hardware, software and OS in mobile platform.
   2. Data control access in ME/USIM.
   3. Maintenance of confidentiality and integrity of data stored in the ME/USIM or transported on the interface between ME and USIM.
   4. User identity privacy retention to ME.
2. Security requirements on radio interface and network operator:
   1. Entity authentication: mutual authentication between user and network shall be implemented to ensure secure service access and provision.
   2. Ensure confidentiality of data including user traffic and signaling data on wired or wireless interface.
   3. Ensure integrity and origin authentication of user traffic, signaling data and control data.
   4. Security of user identity: It shall protect user identity confidentiality, user location confidentiality and user untraceability.
   5. Lawful interception: It shall be possible for law enforcement agencies to monitor and intercept every call in accordance with national laws.
3. Security visibility, configurability and scalability:
   1. Transparency of security features of the visited network to the user.
   2. Ability to negotiate acceptable security lever with the visited network when user roams outside HE (home environment).
   3. Scalability of the security mechanism to support increase of user and/or network elements.

Important Security Issues in 4G & wireless security

With the advent of advanced network of 4G, there are several security issues that are deemed important for consideration when deploying a wireless infrastructure like 4G:

1. Authentication: wireless networks have a large number of subscribers, and each has to be authenticated to ensure the right people are using the network. Since the purpose of 4G is to enable people to communicate from anywhere in the world, the issue of cross region and cross provider authentication becomes an issue.
2. Integrity: With services such as SMS, chat and file transfer it is important that the data arrives without any modifications.
3. Confidentiality: With the increased use of cellular phones in sensitive communication, there is a need for a secure channel in order to transmit information.
4. Access Control: The Cellular device may have files that need to have restricted access to them. The device might access a database where some sort of role based access control is necessary.
5. Operating Systems In Mobile Devices: Cellular Phones have evolved from low processing power, ad-hoc supervisors to high power processors and full fledged operating systems. Some phones may use a Java Based system, others use Microsoft Windows CE and have the same capabilities as a desktop computer. Issues may arise in the OS which might open security holes that can be exploited.
6. Web Services: A Web Service is a component that provides functionality accessible through the web using the standard HTTP Protocol. This opens the cellular device to variety of security issues such as viruses, buffer overflows, denial of service attacks etc.
7. Location Detection: The actual location of a cellular device needs to be kept hidden for reasons of privacy of the user. With the move to IP based networks, the issue arises that a user may be associated with an access point and therefore their location might be compromised.
8. Viruses And Malware: With increased functionality provided in cellular systems, problems prevalent in larger systems such as viruses and malware arise. The first virus that appeared on cellular devices was Liberty. An affected device can also be used to attack the cellular network infrastructure by becoming part of a large scale denial of service attack.
9. Downloaded Contents: Spyware or Adware might be downloaded causing security issues. Another problem is that of digital rights management. Users might download unauthorized copies of music, videos, wallpapers and games.
   
   
10. Device Security: If a device is lost or stolen, it needs to be protected from unauthorized use so that potential sensitive information such as emails, documents, phone numbers etc. cannot be accessed.

CURRENT RESEARCH FOR MOBILITY MANAGEMENT IN 4G

There is considerable research being done on mobility management. Mobility solutions can be found by either developing improvements within the current architecture, or by revising the architecture to reflect the changing environment. The solutions propose different addressing and packet forwarding schemes. Almost all of them are IP based solutions, which allow interoperability and easy integration with the existing architectures. Within each of the solutions the relevance to mobility and their strengths and limitations, are discussed in brief:

1. The Internet Indirection Infrastructure is a scalable, self-organizing scheme which easily integrates with legacy systems. It proposes an architecture that offers a communication abstraction based on rendezvous points in an overlay network. When a host wants to send a packet, it forwards the packet to one of the servers it knows. A packet keeps traversing the network till the target server is reached; this leads to delay in route discovery and packet forwarding.
2. FARA (Forwarding directive, Association, and Rendezvous Architecture) is an ongoing project whose main purpose is to provide mobility by separating location from identity. One advantage is that neither an entirely new namespace nor a globally unique one is required for the entities. It allows several different forwarding mechanisms to co-exist in the network, resulting in variability in characteristics like mobility, identity, and anonymity. However, FARA model fails to take into consideration many packet forwarding issues like performance of network nodes, or the balance of anonymity vs. identity for communicating endnodes. It does not accommodate for security either.
3. Host Identity Payload (HIP) provides another way of breaking the binding between identities and topological locations of network nodes. HIP introduces new cryptographic identities that can be dynamically mapped to IP addresses. However, HIP Host Identity (HI). being a public key, is not practical in all actions; it is somewhat long, it needs to be hashed before being used in IPv6 applications. While providing support for mobility and multi-homing with a major architectural change in the addressing concept, the solution requires only small changes in current host implementations.
4. IST MIND develops the concepts and protocols generated in BRAIN by enabling hosts to cooperate with self-organizing wireless ad-hoc networks. It provides independent, interoperable solutions for local/micro-mobility from global mobility.
5. DRIVE specifies a multi-access architecture allowing for seamless intersystem- handover. The concept of a host-controlled flow control was developed to enable parallel usage of different access systems. The architecture is based on Hierarchical Mobile IP, extended by an AAA (Authentication, Authorization and Accounting) component. Over DRiVE extends the scenario with moving networks (e.g. vehicles, trains, etc.) in a multiradio/multi-access environment, defines a Mobile IP-based solution, and focuses on multicast support. The project has strong influence on the ongoing work within the IETF NEMO (Network Mobility) group.
6. The Architectural Principles of Ambient Networks require the integration of a multitude of different communication environments, rather than suffering from heterogeneity. The approach is to use network composition as the principle instead of terminals; networks as such can form the basic building block of the communication architecture. Network composition is a more powerful concept than the simple internetworking as enabled by the Internet Protocol. The current Internet assumes homogeneity in the environment in which to provide control. Ambient Networks have the potential to solve this issue of fragmented control.
7. Developing Standards for Seamless & Secure Mobility: Several industry consortia and standard development organizations such as the IEEE 802 LAN/MAN Standards Committee and the Internet Engineering Task Force (IETF) are expending considerable efforts to develop a common framework and extend existing mobility protocols in order to facilitate and optimize handover performance. Various activities are currently under way, including extensions to Mobile IP at the IETF, and the formation of the Media Independent Handover (MIH) working group in IEEE 802, in addition to several task groups within IEEE 802.11 in order to deal with roaming (IEEE 802. 11r) and interfacing to external networks (IEEE 802.11u) .
8. Interference Alignment Techniques for Wireless Interference Channels: The project is going at Samsung Advanced Institute of Technology, Korea from Nov. 2008 onwards.
9. Transmission Techniques for Multiple MIMO Relay Channels: This project is being developed at LG Electronics, Korea from Aug. 2008.
10. Physical Layer Design for High-speed wireless Systems (9^th): The project is going at Interstate Technology & Regulatory Council.

The best solution among the current and ongoing projects will be the one that successfully addresses all the related challenges as well as allows scalability for future possibilities. A few open issues, however, need to be addressed in most of the existing projects; i.e. synchronization of the entire network and sound QoS.