1,090 research outputs found
Low energy indoor network : deployment optimisation
This article considers what the minimum energy indoor access point deployment is in order to achieve a certain downlink quality-of-service. The article investigates two conventional multiple-access technologies, namely: LTE-femtocells and 802.11n Wi-Fi. This is done in a dynamic multi-user and multi-cell interference network. Our baseline results are reinforced by novel theoretical expressions. Furthermore, the work underlines the importance of considering optimisation when accounting for the capacity saturation of realistic modulation and coding schemes. The results in this article show that optimising the location of access points both within a building and within the individual rooms is critical to minimise the energy consumption
Optimal Rate Sampling in 802.11 Systems
In 802.11 systems, Rate Adaptation (RA) is a fundamental mechanism allowing
transmitters to adapt the coding and modulation scheme as well as the MIMO
transmission mode to the radio channel conditions, and in turn, to learn and
track the (mode, rate) pair providing the highest throughput. So far, the
design of RA mechanisms has been mainly driven by heuristics. In contrast, in
this paper, we rigorously formulate such design as an online stochastic
optimisation problem. We solve this problem and present ORS (Optimal Rate
Sampling), a family of (mode, rate) pair adaptation algorithms that provably
learn as fast as it is possible the best pair for transmission. We study the
performance of ORS algorithms in both stationary radio environments where the
successful packet transmission probabilities at the various (mode, rate) pairs
do not vary over time, and in non-stationary environments where these
probabilities evolve. We show that under ORS algorithms, the throughput loss
due to the need to explore sub-optimal (mode, rate) pairs does not depend on
the number of available pairs, which is a crucial advantage as evolving 802.11
standards offer an increasingly large number of (mode, rate) pairs. We
illustrate the efficiency of ORS algorithms (compared to the state-of-the-art
algorithms) using simulations and traces extracted from 802.11 test-beds.Comment: 52 page
Experimental Evaluation of Large Scale WiFi Multicast Rate Control
WiFi multicast to very large groups has gained attention as a solution for
multimedia delivery in crowded areas. Yet, most recently proposed schemes do
not provide performance guarantees and none have been tested at scale. To
address the issue of providing high multicast throughput with performance
guarantees, we present the design and experimental evaluation of the Multicast
Dynamic Rate Adaptation (MuDRA) algorithm. MuDRA balances fast adaptation to
channel conditions and stability, which is essential for multimedia
applications. MuDRA relies on feedback from some nodes collected via a
light-weight protocol and dynamically adjusts the rate adaptation response
time. Our experimental evaluation of MuDRA on the ORBIT testbed with over 150
nodes shows that MuDRA outperforms other schemes and supports high throughput
multicast flows to hundreds of receivers while meeting quality requirements.
MuDRA can support multiple high quality video streams, where 90% of the nodes
report excellent or very good video quality
TOWARDS A HOLISTIC RATE ADAPTION FOR 802.1 1N/AC MIMO SYSTEMS
Master'sMASTER OF SCIENC
Advanced Wireless LAN
The past two decades have witnessed starling advances in wireless LAN technologies that were stimulated by its increasing popularity in the home due to ease of installation, and in commercial complexes offering wireless access to their customers. This book presents some of the latest development status of wireless LAN, covering the topics on physical layer, MAC layer, QoS and systems. It provides an opportunity for both practitioners and researchers to explore the problems that arise in the rapidly developed technologies in wireless LAN
Throughput and range characterization of IEEE 802.11ah
The most essential part of Internet of Things (IoT) infrastructure is the
wireless communication system that acts as a bridge for the delivery of data
and control messages. However, the existing wireless technologies lack the
ability to support a huge amount of data exchange from many battery driven
devices spread over a wide area. In order to support the IoT paradigm, the IEEE
802.11 standard committee is in process of introducing a new standard, called
IEEE 802.11ah. This is one of the most promising and appealing standards, which
aims to bridge the gap between traditional mobile networks and the demands of
the IoT. In this paper, we first discuss the main PHY and MAC layer amendments
proposed for IEEE 802.11ah. Furthermore, we investigate the operability of IEEE
802.11ah as a backhaul link to connect devices over a long range. Additionally,
we compare the aforementioned standard with previous notable IEEE 802.11
amendments (i.e. IEEE 802.11n and IEEE 802.11ac) in terms of throughput (with
and without frame aggregation) by utilizing the most robust modulation schemes.
The results show an improved performance of IEEE 802.11ah (in terms of power
received at long range while experiencing different packet error rates) as
compared to previous IEEE 802.11 standards.Comment: 7 pages, 6 figures, 5 table
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