CogCell: Cognitive Interplay between 60GHz Picocells and 2.4/5GHz Hotspots in the 5G Era

Rapid proliferation of wireless communication devices and the emergence of a variety of new applications have triggered investigations into next-generation mobile broadband systems, i.e., 5G. Legacy 2G--4G systems covering large areas were envisioned to serve both indoor and outdoor environments. However, in the 5G-era, 80\% of overall traffic is expected to be generated in indoors. Hence, the current approach of macro-cell mobile network, where there is no differentiation between indoors and outdoors, needs to be reconsidered. We envision 60\,GHz mmWave picocell architecture to support high-speed indoor and hotspot communications. We envisage the 5G indoor network as a combination of-, and interplay between, 2.4/5\,GHz having robust coverage and 60\,GHz links offering high datarate. This requires an intelligent coordination and cooperation. We propose 60\,GHz picocellular network architecture, called CogCell, leveraging the ubiquitous WiFi. We propose to use 60\,GHz for the data plane and 2.4/5GHz for the control plane. The hybrid network architecture considers an opportunistic fall-back to 2.4/5\,GHz in case of poor connectivity in the 60\,GHz domain. Further, to avoid the frequent re-beamforming in 60\,GHz directional links due to mobility, we propose a cognitive module -- a sensor-assisted intelligent beam switching procedure -- which reduces the communication overhead. We believe that the CogCell concept will help future indoor communications and possibly outdoor hotspots, where mobile stations and access points collaborate with each other to improve the user experience.Comment: 14 PAGES in IEEE Communications Magazine, Special issue on Emerging Applications, Services and Engineering for Cognitive Cellular Systems (EASE4CCS), July 201

Protocolos multibanda para descoberta de vizinhança em redes ad hoc de ondas milimétricas

Propagation at millimeter waves band, i.e. up from 30 GHz, is very susceptible to path loss attenuation, which can be mitigated using highly directional antennas. Hence, the usage of millimeter waves band in ad hoc networks increases the complexity of neighbor discovery since the knowledge of neighbors’ physical location becomes essential to proceed with communication. To face these challenges, multiband protocols have been proposed, which uses an omnidirectional control channel in a different band from millimeter waves data channel. Due to unstable characteristics of millimeter waves channel, the control channel is used to transmit information concerning neighbor discovery. The two protocols proposed in this work rely on this feature and aim to build a global knowledge about nodes’ location as well as to maintain it in the case of nodes mobility or if some obstacle arises. Both protocols are compared with another protocol found in the literature in terms of delay on the neighbor discoveryA propagação na banda de ondas milimétricas, ou seja, a partir de 30 GHz, é altamente suscetível à atenuação por perda de percurso. Esta acentuada atenuação é mitigada pelo uso de antenas altamente direcionais. Assim, o uso da banda de ondas milimétricas em redes ad hoc aumenta a complexidade na descoberta de vizinhos, pois se torna essencial obter a localização física dos vizinhos para proceder com a comunicação. Para lidar com esse desafio, protocolos multibanda foram propostos na literatura, os quais fazem uso de um canal de controle omnidirecional em uma banda diferente do canal de dados em ondas milimétricas. Devido às instabilidades deste último canal, o canal de controle é usado para transmissão das informações pertinentes à realização de busca dos vizinhos. Os dois protocolos propostos neste trabalho fazem uso dessa funcionalidade e visam construir o conhecimento do posicionamento de todos os nós da rede, assim como manter esta informação em caso de mudanças de posicionamento ou surgimento de obstáculos. Ambos os protocolos são comparados com um outro protocolo da literatura em termos da latência na descoberta de vizinhança