14 research outputs found
Blind Interference Alignment in General Heterogeneous Networks
Heterogeneous networks have a key role in the design of future mobile
communication networks, since the employment of small cells around a macrocell
enhances the network's efficiency and decreases complexity and power demand.
Moreover, research on Blind Interference Alignment (BIA) has shown that optimal
Degrees of Freedom (DoF) can be achieved in certain network architectures, with
no requirement of Channel State Information (CSI) at the transmitters. Our
contribution is a generalised model of BIA in a heterogeneous network with one
macrocell with K users and K femtocells each with one user, by using Kronecker
(Tensor) Product representation. We introduce a solution on how to vary
beamforming vectors under power constraints to maximize the sum rate of the
network and how optimal DoF can be achieved over K+1 time slots.Comment: 5 pages, 7 figures, accepted to IEEE PIMRC'1
Interference Management in Heterogeneous Networks with Blind Transmitters
Future multi-tier communication networks will require enhanced network
capacity and reduced overhead. In the absence of Channel State Information
(CSI) at the transmitters, Blind Interference Alignment (BIA) and Topological
Interference Management (TIM) can achieve optimal Degrees of Freedom (DoF),
minimising network's overhead. In addition, Non-Orthogonal Multiple Access
(NOMA) can increase the sum rate of the network, compared to orthogonal radio
access techniques currently adopted by 4G networks. Our contribution is two
interference management schemes, BIA and a hybrid TIM-NOMA scheme, employed in
heterogeneous networks by applying user-pairing and Kronecker Product
representation. BIA manages inter- and intra-cell interference by antenna
selection and appropriate message scheduling. The hybrid scheme manages
intra-cell interference based on NOMA and inter-cell interference based on TIM.
We show that both schemes achieve at least double the rate of TDMA. The hybrid
scheme always outperforms TDMA and BIA in terms of Degrees of Freedom (DoF).
Comparing the two proposed schemes, BIA achieves more DoF than TDMA under
certain restrictions, and provides better Bit-Error-Rate (BER) and sum rate
performance to macrocell users, whereas the hybrid scheme improves the
performance of femtocell users.Comment: 30 pages, 18 figure
A hybrid TIM-NOMA scheme for the SISO Broadcast Channel
Future mobile communication networks will require enhanced network efficiency
and reduced system overhead due to their user density and high data rate
demanding applications of the mobile devices. Research on Blind Interference
Alignment (BIA) and Topological Interference Management (TIM) has shown that
optimal Degrees of Freedom (DoF) can be achieved, in the absence of Channel
State Information (CSI) at the transmitters, reducing the network's overhead.
Moreover, the recently emerged Non-Orthogonal Multiple Access (NOMA) scheme
suggests a different multiple access approach, compared to the current
orthogonal methods employed in 4G networks, resulting in high capacity gains.
Our contribution is a hybrid TIM-NOMA scheme in Single-Input-Single-Output
(SISO) K-user cells, in which users are divided into T groups, and 1/T DoF is
achieved for each user. By superimposing users in the power domain, we
introduce a two-stage decoding process, managing 'inter-group' interference
based on the TIM principles, and 'intra-group' interference based on Successful
Interference Cancellation (SIC), as proposed by NOMA. We show that for high SNR
values the hybrid scheme can improve the sum rate by at least 100% when
compared to Time Division Multiple Access (TDMA).Comment: 6 pages, 6 figures, submitted to IEEE ICC'15 - IEEE SCAN Worksho
5G-XHaul:a converged optical and wireless solution for 5G transport networks
This is the pre-peer reviewed version of the following article: Gutiérrez-Terán, J., Maletic, N., Camps, D., Garcia-Villegas, E., Berberana, I., Anastasopoulos, M., Tzanakaki, A., Kalokidou, V., Flegkas, P., Syrivelis, D., Korakis, T., Legg, P., Markovic, D., Limperopoulos, G., Bartelt, J., Chaudhary, J.K., Grieger, M., Vucic, N., Zou, J., Grass, E. 5G-XHaul: a converged optical and wireless solution for 5G transport networks. "Transactions on emerging telecommunications technologies", 8 Juliol 2016, vol. 27, núm. 9, p. 1187-1195, which has been published in final form at http://onlinelibrary.wiley.com.recursos.biblioteca.upc.edu/doi/10.1002/ett.3063/epdf. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The common European Information and Communications Technology sector vision for 5G is that it should leverage on the strengths of both optical and wireless technologies. In the 5G context, a wide spectra of radio access technologies—such as millimetre wave transmission, massive multiple-input multiple-output and new waveforms—demand for high capacity, highly flexible and convergent transport networks. As the requirements imposed on future 5G networks rise, so do the challenges in the transport network. Hence, 5G-XHaul proposes a converged optical and wireless transport network solution with a unified control plane based on software defined networking. This solution is able to support the flexible backhaul and fronthaul—X-Haul—options required to tackle the future challenges imposed by 5G radio access technologies. 5G-XHaul studies the trade-offs involving fully or partially converged backhaul and fronthaul functions, with the aim of maximising the associated sharing benefits, improving efficiency in resource utilisation and providing measurable benefits in terms of overall cost, scalability and sustainabilityPeer ReviewedPostprint (published version