60,912 research outputs found
Device-to-Device Assisted Video Transmission
To increase spectrum efficiency, researchers envi- sion a device-to-device (D2D) communication system in which a closely located mobile device pair may share the same spectrum with a cellular user. By opportunistically choosing the frequency, the D2D pair may increase the spectrum efficiency in terms of data rate per Hertz, at the price of additional interference to that cellular user. In previous models, users either stop cellular transmission and switch to D2D transmission or vice versa. However, if the cell is fully loaded, a D2D pair will not be able to switch back to the conventional mode because no extra resource is available. In this paper, we propose a D2D assisted model, where a D2D link is enabled to assist transmission, while keeping the conventional cellular transmission. In this way, the D2D link can be turned on and off according to the link quality. We also propose a PHY-layer study for the transmission scheme in such a way that the system throughput and the video reception quality is always improved compared to a conventional link
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
A Novel Device-to-Device Discovery Scheme for Underlay Cellular Networks
Tremendous growing demand for high data rate services such as video, gaming
and social networking in wireless cellular systems, attracted researchers'
attention to focus on developing proximity services. In this regard,
device-to-device (D2D) communications as a promising technology for future
cellular systems, plays crucial rule. The key factor in D2D communication is
providing efficient peer discovery mechanisms in ultra dense networks. In this
paper, we propose a centralized D2D discovery scheme by employing a signaling
algorithm to exchange D2D discovery messages between network entities. In this
system, potential D2D pairs share uplink cellular users' resources with
collision detection, to initiate a D2D links. Stochastic geometry is used to
analyze system performance in terms of success probability of the transmitted
signal and minimum required time slots for the proposed discovery scheme.
Extensive simulations are used to evaluate the proposed system performance.Comment: Accepted for publication in 25'th Iranian Conference on Electrical
Engineering (ICEE2017
- …