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Power control is an important functionality in radio resource management (RRM) of wireless communication systems, especially the cellular ones. This importance comes from the fact that the transmission power is an essential radio resource and must be employed in an efficient way. Power control techniques must attain two different objectives: minimize the interference in the wireless system and save...
This chapter presents a broad study on the potential of applying radio resource management (RRM) techniques to the global system for mobile communication (GSM)/enhanced data rate for GSM evolution (EDGE) system. Even though the presented results are focused on the GSM/EDGE system, the principles employed by most of the considered RRM techniques can be applied to other radio access networks (RANs)...
Over the last few years, there has been a substantial growth in broadband Internet access worldwide driven by intensifying competition and by regulatory measures to improve competitor access to local loops. In the fixed broadband business, asymmetric digital subscriber lines (ADSL) remain the key technology, followed by cable networks.
A wireless cellular network operates normally when the offered traffic load stays around or below a target point efined in the network planning phase. The network is able to work in an optimized way thanks to the operation of RRM algorithms, which meet the contracted QoS requirements for the majority of users causing few service outages, and maintain the planned coverage. However, there can be a mismatch...
International mobile telecommunications (IMT)-advanced systems are mobile systems that include the new capabilities that go beyond those of IMT-2000 as specified by the International Telecommunication Union (ITU). Such systems provide access to a wide range of telecommunication services including advanced mobile services, supported by mobile and fixed networks, which are increasingly packet based.
Multiaccess networks are systems created by the integration of two or more radio access technologyss (RATs) which cooperate, in order to provide a better use of their complementary features, aiming at a higher performance as a whole. In order to achieve this integration, a logical entity called common radio resource management (CRRM) is adopted, whose role is to perform a higher level management....
Performance assessment of wireless communication systems by computer simulations is a valuable and widely adopted tool for research and development, as well as in planning and deployment phases of these systems. It allows the numerical evaluation of a model of the wireless communication system of interest, while featuring speed, inexpensiveness, and flexibility to control the experiments. However,...
In bandlimited, high data rate digital communication systems, equalizers are important devices. Their function is to restore the transmitted information, i.e., the information at the channel input, decreasing or eliminating channel interference. A large variety of techniques have been developed in the last 70 years, following the evolution of communication systems.
The use of OFDM is gaining more and more interest from communications and signal processing communities due to its great potential to cope with frequency-selective channels. Further, OFDM also allows to reduce the complexity for tasks such as equalization and channel estimation in systems where the bandwidth of the channel is wide, when compared to classical (non-OFDM) approaches.
The paradigm of the design of a wireless system has changed. Since the use of the dimensioning for the “worst case”, which means to design the system to work on the fading margin available when the channel has its poorest behavior, the driver of the optimization has evolved to a more suitable use of the available resources for performing a reliable communication
Several existing signal processing problems in wireless communication systems with multiple transmit and/or receive antennas are modeled by means of matrix decompositions that represent the transformations on the transmitted signal from the transmitter to the receiver. At the receiver, signal processing is generally used to combat multipath fading effects, inter-symbol interference, and multiuser...
As described in the previous chapters, multiple-input multiple-output (MIMO) wireless communication systems are able to provide large gains in capacity and link quality by capitalizing either on spatial multiplexing [7, 8, 11, 12, 40] or on space–time coding [1, 39] techniques or, yet, on hybrid combinations of both [6, 14, 44]. Conventional spatial multiplexing and transmit diversity techniques are...
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