3 research outputs found
Cache-Aided Interference Management in Partially Connected Linear Networks
This paper studies caching in (K+L-1) x K partially connected wireless linear
networks, where each of the K receivers locally communicates with L out of the
K+L-1 transmitters, and caches are at all nodes. The goal is to design caching
and delivery schemes to reduce the transmission latency, by using normalized
delivery time (NDT) as the performance metric. For small transmitter cache size
(any L transmitters can collectively store the database just once), we propose
a cyclic caching strategy so that each of every L consecutive transmitters
caches a distinct part of each file; the delivery strategy exploits coded
multicasting and interference alignment by introducing virtual receivers. The
obtained NDT is within a multiplicative gap of 2 to the optimum in the entire
cache size region, and optimal in certain region. For large transmitter cache
size (any L transmitters can collectively store the database for multiple
copies), we propose a modified caching strategy so that every bit is repeatedly
cached at consecutive transmitters; the delivery strategy exploits
self-interference cancellation and interference neutralization. By combining
these schemes, the NDT is optimal in a larger region. We also extend our
results to linear networks with heterogeneous receiver connectivity and
partially connected circular networks.Comment: 22 pages, 7 figures, 2 tables. To appear in IEEE Transactions on
Communication
An Analytical Framework for Delay Optimal Mobile Edge Deployment in Wireless Networks
The emerging edge caching provides an effective way to reduce service delay
for mobile users. However, due to high deployment cost of edge hosts, a
practical problem is how to achieve minimum delay under a proper edge
deployment strategy. In this letter, we provide an analytical framework for
delay optimal mobile edge deployment in a partially connected wireless network,
where the request files can be cached at the edge hosts and cooperatively
transmitted through multiple base stations. In order to deal with the
heterogeneous transmission requirements, we separate the entire transmission
into backhaul and wireless phases, and propose average user normalized delivery
time (AUNDT) as the performance metric. On top of that, we characterize the
trade-off relations between the proposed AUNDT and other network deployment
parameters. Using the proposed analytical framework, we are able to provide the
optimal mobile edge deployment strategy in terms of AUNDT, which provides a
useful guideline for future mobile edge deployment
Degrees of Freedom of Cache-Aided Wireless Cellular Networks
This work investigates the degrees of freedom (DoF) of a downlink cache-aided
cellular network where the locations of base stations (BSs) are modeled as a
grid topology and users within a grid cell can only communicate with four
nearby BSs. We adopt a cache placement method with uncoded prefetching tailored
for the network with partial connectivity. According to the overlapped degree
of cached contents among BSs, we propose transmission schemes with no BS
cooperation, partial BS cooperation, and full BS cooperation, respectively, for
different cache sizes. In specific, the common cached contents among BSs are
utilized to cancel some undesired signals by interference neutralization while
interference alignment is used to coordinate signals of distinct cached
contents. Our achievable results indicate that the reciprocal of per-user DoF
of the cellular network decreases piecewise linearly with the normalized cache
size at each BS, and the gain of BS caching is more significant for the
small cache region. Under the given cache placement scheme, we also provide an
upper bound of per-user DoF and show that our achievable DoF is optimal when
, and within an additive gap of
to the optimum when
.Comment: Part of this work was presented at IEEE WCNC 201