5 research outputs found
Hybrid Spectrum Sharing in mmWave Cellular Networks
While spectrum at millimeter wave (mmWave) frequencies is less scarce than at
traditional frequencies below 6 GHz, still it is not unlimited, in particular
if we consider the requirements from other services using the same band and the
need to license mmWave bands to multiple mobile operators. Therefore, an
efficient spectrum access scheme is critical to harvest the maximum benefit
from emerging mmWave technologies. In this paper, we introduce a new hybrid
spectrum access scheme for mmWave networks, where data is aggregated through
two mmWave carriers with different characteristics. In particular, we consider
the case of a hybrid spectrum scheme between a mmWave band with exclusive
access and a mmWave band where spectrum is pooled between multiple operators.
To the best of our knowledge, this is the first study proposing hybrid spectrum
access for mmWave networks and providing a quantitative assessment of its
benefits. Our results show that this approach provides major advantages with
respect to traditional fully licensed or fully unlicensed spectrum access
schemes, though further work is needed to achieve a more complete understanding
of both technical and non technical implications
MAC Aspects of Millimeter-Wave Cellular Networks
The current demands for extremely high data rate wireless services and the spectrum scarcity at the sub-6 GHz bands are forcefully motivating the use of the millimeter-wave (mmWave) frequencies. MmWave communications are characterized by severe attenuation, sparse-scattering environment, large bandwidth, high penetration loss, beamforming with massive antenna arrays, and possible noise-limited operation. These characteristics imply a major difference with respect to legacy communication technologies, primarily designed for the sub-6 GHz bands, and are posing major design challenges on medium access control (MAC) layer. This book chapter discusses key MAC layer issues at the initial access and mobility management (e.g., synchronization, random access, and handover) as well as resource allocation (interference management, scheduling, and association). The chapter provides an integrated view on MAC layer issues for cellular networks and reviews the main challenges and trade-offs and the state-of-the-art proposals to address them
Spectrum Sharing in mmWave Cellular Networks via Cell Association, Coordination, and Beamforming
This paper investigates the extent to which spectrum sharing in mmWave
networks with multiple cellular operators is a viable alternative to
traditional dedicated spectrum allocation. Specifically, we develop a general
mathematical framework by which to characterize the performance gain that can
be obtained when spectrum sharing is used, as a function of the underlying
beamforming, operator coordination, bandwidth, and infrastructure sharing
scenarios. The framework is based on joint beamforming and cell association
optimization, with the objective of maximizing the long-term throughput of the
users. Our asymptotic and non-asymptotic performance analyses reveal five key
points: (1) spectrum sharing with light on-demand intra- and inter-operator
coordination is feasible, especially at higher mmWave frequencies (for example,
73 GHz), (2) directional communications at the user equipment substantially
alleviate the potential disadvantages of spectrum sharing (such as higher
multiuser interference), (3) large numbers of antenna elements can reduce the
need for coordination and simplify the implementation of spectrum sharing, (4)
while inter-operator coordination can be neglected in the large-antenna regime,
intra-operator coordination can still bring gains by balancing the network
load, and (5) critical control signals among base stations, operators, and user
equipment should be protected from the adverse effects of spectrum sharing, for
example by means of exclusive resource allocation. The results of this paper,
and their extensions obtained by relaxing some ideal assumptions, can provide
important insights for future standardization and spectrum policy.Comment: 15 pages. To appear in IEEE JSAC Special Issue on Spectrum Sharing
and Aggregation for Future Wireless Network
Coverage Probability Optimization Utilizing Flexible Hybrid mmWave Spectrum Slicing-Sharing Access Strategy for 5G Cellular Systems
Spectrum and infrastructure sharing among multiple mobile network operators is a vital solution to substantially and sustainably improves cost and network efficiency. However, such approach may face several challenges, such as the imposed restrictions on the independence of operators, the complexity of spectrum management policies and the mutual interference issues among operators. Therefore, in this study, we propose a flexible hybrid spectrum access strategy, namely, hybrid millimetre wave (mmWave) spectrum slicing–sharing access (HMSSSA), to optimise the coverage probability via distributing the spectrum in a hybrid manner. Accordingly, the interference problem can be addressed, and the coverage probability can be improved. In the proposed strategy, the spectrum splits into three different classes: (i) exclusive right assigned to all of the operators, (ii) semi-pooled among all the operators and (iii) fully pooled (shared) as open access among all the operators with the ultra-flexibility feature. Adaptive hybrid multi-state mmWave cell selection (AHMMC-S) scheme is adopted to optimally associate a typical user to the mmWave base station (mBS) that offers high signal-to-interference plus noise ratio. Numerical results demonstrate that our proposed strategy reduces the outage probability significantly, provides a degree of freedom to the subscribers to optimally select mBS with high signal quality and maintains an acceptable level of mBS densification
Hybrid spectrum access for mmWave networks
While spectrum at millimeter wave (mmWave) frequencies is less scarce than at
traditional frequencies below 6 GHz, still it is not unlimited, in particular
if we consider the requirements from other services using the same band and the
need to license mmWave bands to multiple mobile operators. Therefore, an
efficient spectrum access scheme is critical to harvest the maximum benefit
from emerging mmWave technologies. In this paper, motivated by previous results
where spectrum pooling was proved to be more feasible at high mmWave
frequencies, we study the performance of a hybrid spectrum scheme where
exclusive access is used at frequencies in the 20/30 GHz range while spectrum
pooling/unlicensed spectrum is used at frequencies around 70 GHz. Our
preliminary results show that hybrid spectrum access is a promising approach
for mmWave networks, and motivate further studies to achieve a more complete
understanding of both technical and non technical implications.Comment: Accepted at 15th Annual Mediterranean Ad Hoc Networking Workshop
(MED-HOC-NET), 201