In some countries, cellular wireless roaming charges are prohibitive possibly because the incumbent access-provider is actually or essentially state-run, unlike potential entrants, i.e., the regulator (state) is in a conflict of interest. In other countries, e.g., France, there is a lot of competition among Internet Service (access) Providers (ISPs). Recently, Free purchased a spectrum license ...

It is increasingly difficult to satisfy growing demands for spectrum with the conventional policy of fixed spectrum allocation. To overcome this problem, flexible/dynamic spectrum sharing methods that can significantly improve spectrum utilization of the spectrum have gained increasing interest recently. This paper presents two dynamic spectrum sharing approaches, a centralized and a decentrali...

The role of teacher, family and the background of students in conducting homework and math performance were investigated. Participants were 7,725 Spanish adolescents with the mean age of 13.78 (± .82) and 2,246 teachers who taught the above mentioned students. A two-level hierarchical linear analysis, students (N = 7,541) and classrooms (N = 353), was performed, adjusted for background and prio...

As a kind of intelligent communication technology, the characteristic of dynamic spectrum allocation of cognitive radio provides feasible scheme for sharing with the spectrum resources among the primary user and secondary users, which solves the current spectrum resource scarcity problem. In this paper, we comprehensively explored the cognitive radio spectrum allocation models based on game the...

We consider the problem of online graph multi-coloring with advice. Multi-coloring is often used to model frequency allocation in cellular networks. We give several nearly tight upper and lower bounds for the most standard topologies of cellular networks, paths and hexagonal graphs. For the path, negative results trivially carry over to bipartite graphs, and our positive results are also valid ...

We propose a distributed dynamic frequency allocation algorithm that achieves performance close to that of a centralized optimal algorithm. In our network model, nodes are grouped into a number of clusters. Each cluster chooses its transmission frequency band based on its knowledge of the interference that it experiences. The convergence of the proposed distributed algorithm to a sub-optimal fr...

This paper presents a novel spectrum-allocation technique designed for a high data-rate and spectrally-efficient multiple-user wireless system. The core of this system is a reconfigurable radio, implemented on a General-Purpose Processor (GPP) platform. A type of Dynamic Orthogonal Frequency Division Multiplexing Multiple Access (DOFDMA) is used to transmit a multiplex of several information so...

The IEEE Geoscience and Remote Sensing Society (GRSS) Technical Committee on Frequency Allocation in Remote Sensing (FARS) is charged with providing recommendations and responses to queries on interference and frequency allocation issues in passive and active microwave remote sensing. In response to questions stemming from proposals to develop ultra-widehand (UWB) vehicular radar systems operat...

This paper analyses the performance of the multi cell OFDMA system for the average spectral efficiency and the coverage probability. We form the Chunk by the grouping of the adjacent subcarriers by exploiting the correlation among them. Frequency band allocation is based on the chunk instead of the subcarrier in order to reduce complexity in the sub carrier based resource allocation. In order t...

Orthogonal Frequency Division Multiplexing (OFDM) has the inherent properties of being robust to interference and frequency selective fading and is de facto the adopted multiplexing techniques for the 4 th generation wireless network systems. In wireless system, resources such as bandwidth and power are limited, intelligent allocation of these resources to users are crucial for delivering the b...