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Dynamic Configuration and Optimization of WiMAX Networks with Relay Power Savin...
Robalo, Daniel; Oliveira, João R.; Velez, Fernando J.; Holland, Oliver; Aghvami, A. HamidThis paper investigates the performances achievable by WiMAX networks deployed in various sectorization configurations, with and without relay stations (RSs). Further, it studies the dynamic adjustment of the configuration to serve traffic loads at different times of the day while maximising the use of opportunistic sleep modes by relays in conjunction with cell zooming, thereby saving energy. The configuration...
Cost/revenue performance in an IMT-Advanced scenario with Spectrum Aggregation ...
Acevedo Flores, Jessica Elizabeth; Velez, Fernando J.; Cabral, Orlando; Robalo, Daniel Luís Silveira; Holland, Oliver; Aghvami, A. HamidThis paper determines the cost/revenue performance of a mobile communication system in an IMT-Advanced scenario with integrated Common Radio Resource Management (iCRRM). The iCRRM performs classic CRRM functionalities jointly with Spectrum Aggregation (SA), being able to switch users between non-contiguous frequency bands. The SA scheduling is obtained with an optimized General Multi-Band Scheduling (GMBS) algo...
Energy saving in the optimization of the planning of fixed WiMAX with relays in...
Velez, Fernando J.; Oliveira, João; Robalo, Daniel Luís Silveira; Holland, Oliver; Aghvami, A. HamidLayered and cooperative elements such as femto-cells and relays can improve performance or energy efficiency in mobile networks; however, they consume energy per se and their durations in operational state must therefore be minimised. This paper investigates the use of relays in WiMAX network deployments and concentrates on the cost/revenue performance and energy efficiency trade-off in such cases. Specifically...
Opportunistic spectrum and load management for green radio networks
Holland, Oliver; Facchini, Christian; Aghvami, A. Hamid; Cabral, Orlando Manuel Brito; Velez, FernandoIntroduction Historically, the radio spectrum has been managed in a rather rigid fashion where systems have been constrained to very specific bands in order to avoid interference and maintain the spectrum's viability. This regime is extremely inefficient, because at any one time many systems are not being used thereby leaving their associated spectrum also unused. Alternative spectrum management, where systems ...
Cost/Revenue Tradeoff in the Optimization of Fixed WiMAX Deployment With Relays
Velez, Fernando J.; Nazir, Muhammad Kashif; Aghvami, A. Hamid; Holland, Oliver; Robalo, DanielIn fixed Worldwide Interoperability for Microwave Access (WiMAX), the contribution from each transmission mode can be incorporated into an implicit formulation to obtain the supported throughput as a function of the carrier-to-interference ratio. This is done by weighting the physical throughput in each concentric coverage ring by the size of the ring. In this paper, multihop cells are formed by a central cover...
Fixed WiMAX Profit Maximisation with Energy Saving through Relay Sleep Modes an...
Velez, Fernando J.; del Camino Noguera, Maria; Holland, Oliver; Aghvami, A. HamidIn Fixed WiMAX, the cost/revenue optimisation function for radio and network planning incorporates the cost of building and maintaining the infrastructure and the impact of the available resources on revenues. Supported throughput typically decreases with larger cells due to the implied greater average distance of users from the base station, although the use of subchannelisation can keep throughput steady with...
Opportunistic load and spectrum management for mobile communications energy eff...
Holland, Oliver; Cabral, Orlando; Velez, Fernando; Aijaz, Adnan; Pangalos, Paul; Aghvami, A. HamidDynamic load and spectrum usage management techniques can significantly improve the energy efficiency of mobile communications systems. This paper considers: (i) the opportunistic reallocation of traffic loads between bands to allow radio network equipment in the bands that the traffic is originated from to be powered down, and (ii) the opportunistic selection of more appropriate spectrum based on propagation c...
Intra-operator spectrum sharing concepts for energy efficiency and throughput e...
Holland, Oliver; Attar, Alireza; Cabral, Orlando Manuel Brito; Velez, Fernando J.; Aghvami, A. HamidCognitive radio and other dynamic spectrum sharing paradigms have enjoyed the limelight recently for their potential to realize a number of benefits for communications systems. The majority of investigated solutions thus far have looked at primary/secondary access and sharing of spectrum among different spectrum owners. In contrast, this paper investigates solutions for spectrum sharing among different bands ow...
Radio and Network Planning
Velez, Fernando J.; Sebastião, Pedro; Costa, Rui; Robalo, Daniel; Comissário, Cláudio; Rodrigues, António; Aghvami, A. HamidThis chapter starts by presenting the Stanford University Interim (SUI) and modified Friis propagation models. Although the SUI model is being recommended for WiMAX, the comparison between the model and experimental results show that, in our environment, at 3.5 GHz, the modified Friis model with gama = 3 fits better the measurement values. From the analyses of the signal-to-noise-plusinterference ratio, SNIR, i...
System Capacity
Velez, Fernando J.; Nazir, Muhammad Kashif; Aghvami, A. Hamid; Holland, Oliver; Robalo, DanielIn Fixed WiMAX, the contribution from each transmission mode can be incorporated into an implicit formulation to obtain the supported throughput as a function of the carrier-to-interference ratio. This is done by weighting the physical throughput in each concentric coverage ring by the size of the ring. In this paper, multi-hop cells are formed by a central coverage zone and three outer coverage zones served by...