IPv6 is a reality. Network technologies, services and support systems are ready for it, with IPv6 device support widely available and operators already deploying IPv6 in their networks.
WCDMA/HSPA enables hundreds of millions of people to access mobile broadband (MBB) through their smartphones every day as part of their daily lives. Today, new, low-priced WCDMA/HSPA smartphones are entering the market, and they will enable MBB for new hundreds-of-million-sized markets.
Since the seminal paper by Knopp and Humblet that showed that the system throughput of a singlecel l system is maximized if only one terminal transmits at a time, there has been a large interest in opportunistic communications and its relation to various fairness measures. On the other hand, in multicel l systems there is a need to allocate transmission power such that some overall utility function is maximized typically under fairness constraints. Furthermore, in multicell systems the degree of resource allocation freedom includes the serving cell selection that allows for load balancing and thereby the efficient use of radio resources. In this paper we formulate the joint serving cell selection (link selection) and power allocation problem as an optimization task whose purpose is to maximize either the minimum user throughput or the multicell sum throughput. The max-min problem and a simplified max throughput problem are both NP-hard and we therefore propose heuristic solution approaches.We present numerical results that give new and valuable insights into the trade off between fair and sum throughput optimal joint resource allocation strategies.
Device-to-device (D2D) communications underlaying a cellular infrastructure has been proposed as a means of taking advantage of the physical proximity of communicating devices, increasing resource utilization, and improving cellular coverage. Relative to the traditional cellular methods, there is a need to design new peer discovery methods, physical layer procedures, and radio resource management algorithms that help realize the potential advantages of D2D communications. In this article we use the 3GPP Long Term Evolution system as a baseline for D2D design, review some of the key design challenges, and propose solution approaches that allow cellular devices and D2D pairs to share spectrum resources and thereby increase the spectrum and energy efficiency of traditional cellular networks. Simulation results illustrate the viability of the proposed design.