665 research outputs found
Short-Packet Transmission over a Bidirectional Massive MIMO link
We consider the transmission of short packets over a bidirectional
communication link where multiple devices, e.g., sensors and actuators,
exchange small-data payloads with a base station equipped with a large antenna
array. Using results from finite-blocklength information theory, we
characterize the minimum SNR required to achieve a target error probability for
a fixed packet length and a fixed payload size. Our nonasymptotic analysis,
which applies to the scenario in which the bidirectional communication is
device-initiated, and also to the more challenging case when it is base-station
initiated, provides guidelines on the design of massive multiple-input
multiple-output links that need to support sporadic ultra-reliable low-latency
transmissions. Specifically, it allows us to determine the optimal amount of
resources that need to be dedicated to the acquisition of channel state
information.Comment: 5 pages, presented at Asiloma
Short-Packet Transmission over a Bidirectional Massive MIMO link
We consider the transmission of short packets over a bidirectional communication link where multiple devices, e.g., sensors and actuators, exchange small-data payloads with a base station equipped with a large antenna array. Using results from finite-blocklength information theory, we characterize the minimum SNR required to achieve a target error probability for a fixed packet length and a fixed payload size. Our nonasymptotic analysis, which applies to the scenario in which the bidirectional communication is device-initiated, and also to the more challenging case when it is base-station initiated, provides guidelines on the design of massive multiple-input multiple-output links that need to support sporadic ultra-reliable low-latency transmissions. Specifically, it allows us to determine the optimal amount of resources that need to be dedicated to the acquisition of channel state information
Fronthaul evolution: From CPRI to Ethernet
It is proposed that using Ethernet in the fronthaul, between base station baseband unit (BBU) pools and remote radio heads (RRHs), can bring a number of advantages, from use of lower-cost equipment, shared use of infrastructure with fixed access networks, to obtaining statistical multiplexing and optimised performance through probe-based monitoring and software-defined networking. However, a number of challenges exist: ultra-high-bit-rate requirements from the transport of increased bandwidth radio streams for multiple antennas in future mobile networks, and low latency and jitter to meet delay requirements and the demands of joint processing. A new fronthaul functional division is proposed which can alleviate the most demanding bit-rate requirements by transport of baseband signals instead of sampled radio waveforms, and enable statistical multiplexing gains. Delay and synchronisation issues remain to be solved
Quantifying Potential Energy Efficiency Gain in Green Cellular Wireless Networks
Conventional cellular wireless networks were designed with the purpose of
providing high throughput for the user and high capacity for the service
provider, without any provisions of energy efficiency. As a result, these
networks have an enormous Carbon footprint. In this paper, we describe the
sources of the inefficiencies in such networks. First we present results of the
studies on how much Carbon footprint such networks generate. We also discuss
how much more mobile traffic is expected to increase so that this Carbon
footprint will even increase tremendously more. We then discuss specific
sources of inefficiency and potential sources of improvement at the physical
layer as well as at higher layers of the communication protocol hierarchy. In
particular, considering that most of the energy inefficiency in cellular
wireless networks is at the base stations, we discuss multi-tier networks and
point to the potential of exploiting mobility patterns in order to use base
station energy judiciously. We then investigate potential methods to reduce
this inefficiency and quantify their individual contributions. By a
consideration of the combination of all potential gains, we conclude that an
improvement in energy consumption in cellular wireless networks by two orders
of magnitude, or even more, is possible.Comment: arXiv admin note: text overlap with arXiv:1210.843
Millimeter-wave Wireless LAN and its Extension toward 5G Heterogeneous Networks
Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are
considered as a promising solution for gigabit short range wireless
communication systems. IEEE standard 802.11ad, also known as WiGig, is
standardized for the usage of the 60 GHz unlicensed band for wireless local
area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved
to support bandwidth-intensive multimedia applications. Exhaustive search along
with beamforming (BF) is usually used to overcome 60 GHz channel propagation
loss and accomplish data transmissions in such mmw WLANs. Because of its short
range transmission with a high susceptibility to path blocking, multiple number
of mmw access points (APs) should be used to fully cover a typical target
environment for future high capacity multi-Gbps WLANs. Therefore, coordination
among mmw APs is highly needed to overcome packet collisions resulting from
un-coordinated exhaustive search BF and to increase the total capacity of mmw
WLANs. In this paper, we firstly give the current status of mmw WLANs with our
developed WiGig AP prototype. Then, we highlight the great need for coordinated
transmissions among mmw APs as a key enabler for future high capacity mmw
WLANs. Two different types of coordinated mmw WLAN architecture are introduced.
One is the distributed antenna type architecture to realize centralized
coordination, while the other is an autonomous coordination with the assistance
of legacy Wi-Fi signaling. Moreover, two heterogeneous network (HetNet)
architectures are also introduced to efficiently extend the coordinated mmw
WLANs to be used for future 5th Generation (5G) cellular networks.Comment: 18 pages, 24 figures, accepted, invited paper
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