5,111 research outputs found
60 GHz Blockage Study Using Phased Arrays
The millimeter wave (mmWave) frequencies offer the potential for enormous
capacity wireless links. However, designing robust communication systems at
these frequencies requires that we understand the channel dynamics over both
time and space: mmWave signals are extremely vulnerable to blocking and the
channel can thus rapidly appear and disappear with small movement of obstacles
and reflectors. In rich scattering environments, different paths may experience
different blocking trajectories and understanding these multi-path blocking
dynamics is essential for developing and assessing beamforming and
beam-tracking algorithms. This paper presents the design and experimental
results of a novel measurement system which uses phased arrays to perform
mmWave dynamic channel measurements. Specifically, human blockage and its
effects across multiple paths are investigated with only several microseconds
between successive measurements. From these measurements we develop a modeling
technique which uses low-rank tensor factorization to separate the available
paths so that their joint statistics can be understood.Comment: To appear in the Proceedings of the 51st Asilomar Conference on
Signals, Systems, and Computers, 201
A Normalization Model for Analyzing Multi-Tier Millimeter Wave Cellular Networks
Based on the distinguishing features of multi-tier millimeter wave (mmWave)
networks such as different transmit powers, different directivity gains from
directional beamforming alignment and path loss laws for line-of-sight (LOS)
and non-line-of-sight (NLOS) links, we introduce a normalization model to
simplify the analysis of multi-tier mmWave cellular networks. The highlight of
the model is that we convert a multi-tier mmWave cellular network into a
single-tier mmWave network, where all the base stations (BSs) have the same
normalized transmit power 1 and the densities of BSs scaled by LOS or NLOS
scaling factors respectively follow piecewise constant function which has
multiple demarcation points. On this basis, expressions for computing the
coverage probability are obtained in general case with beamforming alignment
errors and the special case with perfect beamforming alignment in the
communication. According to corresponding numerical exploration, we conclude
that the normalization model for multi-tier mmWave cellular networks fully
meets requirements of network performance analysis, and it is simpler and
clearer than the untransformed model. Besides, an unexpected but sensible
finding is that there is an optimal beam width that maximizes coverage
probability in the case with beamforming alignment errors.Comment: 7 pages, 4 figure
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