Other Challenging Issues

Other Challenging Issues
Several other technologies can be thought of as essential for B3G systems and require more research.
• Ultra-wideband (UWB) techniques3 for short-range communications.
• Optical wireless techniques for short-range communications. • Techniques for seamless vertical and horizontal handovers.
• Cross-layer design and optimization.
• Advanced RRM, with multidimensional. scheduling (time, frequency, space) and intelligent
radio technology4.
• Techniques for reducing the PAPR problem typical of multi-carrier systems.
• Advanced channel coding techniques (turbo codes, LDPC codes,5 etc.).
• Sensor networks.
• Mesh networks.
• Network security.
• Battery technology.
Introducing a new system always involves risks, and B3G is not an exception, even when considering
that it will also integrate legacy systems. Integration in B3G means having different networks,
different terminals, and different services working together seamlessly. It is precisely the integrative
capability of B3G that is one of the crucial challenges, as access solutions for different B3G
scenarios are being developed independently by different parties. Seamless operation is one of the
pillars of B3G, implying transparent intra- and internetwork (horizontal/vertical) handovers. Turning
a very heterogeneous network into a single, simple, and monolithic network (in the eyes of the user)
could entail a colossal task, in particular, if the integration aspects are left for the final phase of B3G
development after different access techniques are developed. The risk is not only in the integration
of access technologies but also in their adoption. Indeed, not all proponent solutions being currently
developed are complementary; many of them would compete with each other [532].
Here is another list of challenges facing the developers of B3G systems:
• Lower price points only slightly higher than alternatives.
• More coordination among spectrum regulators around the world.
• More academic research.
• Standardization of wireless networks in terms of modulation techniques, switching schemes,
and roaming is an absolute necessity for B3G.
• Justification for voice- independent business.
• Integration across different network topologies.
• Nondisruptive implementation: B3G must allow us to move from 3G to B3G [550].