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

Sensor-Assisted Movement Identification and Prediction for Beamformed 60 GHz Links

The 60 GHz frequency band promises very high data rates { in the order of Gb/s { due to the availability of large amounts of bandwidth. High free- space path loss at the 60 GHz frequency band makes it necessary to employ beamforming capable directional antennas to confine signal power in the desired direction. When beamforming is used, the links are sensitive to misalignment in antenna directionality, due to the movement of devices. To identify and circumvent the misalignments, we propose to use motion sensors (i.e., accelerometer and gyroscope) which are already present in most modern mobile devices. By finding the extent of misaligned beams, corrective actions are carried out to reconfigure the antennas. Motion sensors in mobile devices provide means to estimate the extent of misalignments. We collected real data from motion sensors and steered the beams appropriately. The results from our study show that the sensors are capable of detecting the cause of the error as translational or rotational movements. Furthermore it is also shown that sensor data can be used to predict the next location of the user. This can be used to reconfigure the directional antenna to switch the antenna beam and hence avoid frequent link disruptions. This decreases the number of beam searches, thus lowering the MAC overhead.Embedded SoftwareEmbedded SystemsElectrical Engineering, Mathematics and Computer Scienc