Emerging cognitive radio networking technology potentially provides a promising solution to the spectrum underutilization problem in wireless access. In this paper, a cross-layer routing for secondary multihop is studied in cognitive radio network operating in television white spaces. The framework considers a joint channel, power, and routing assignment under signal to interference noise ratio (SINR) constraints. The problem is formulated as a maximum concurrent multicommodity flow problem. The goal of conducting this research is to develop a new routing protocol for the secondary multihop cognitive radio network. Therefore, the objective of this paper focuses on maximizing a flow rate scaling factor. Moreover, the paper focuses on achieving multipath routing when it is possible under SINR constraints to utilize all possible unused channels efficiently. The numerical results proved the strength of the proposed algorithm in its routing ability under the physical model of SINR, in addition to the ability of using multipath routing if there are available free channels to be used in the cognitive communication paradigm.
In this paper, the reverse link Erlang traffic capacity of a power controlled CDMA based Wireless Local Loop (WLL) voice system equipped with high gain directional antennas at either the base station or users' houses is investigated. It is shown that the Erlang traffic capacity of CDMA based WLL system is several times that of mobile cellular CDMA system and conventional multiple access systems, such as FDMA and TDMA based systems. Finally the study of Telecom Egypt WLL CDMA2000-1xRTT network is examined as a case study.
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