IMDEA Networks Institute Digital Repository
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Millimeter Wave Networking Challenges
No full textState-of-the-art wireless communication already operates close to Shannon capacity and one of the most promising options to further increase data rates is to increase the communication bandwidth. Very high bandwidth channels are only available in the extremely high frequency part of the radio spectrum, the millimeter wave band (mm-wave). Upcoming communication technologies, such as IEEE 802.11ad, are already starting to exploit this part of the radio spectrum to achieve data rates of several GBit/s. However, communication at such high frequencies also suffers from high attenuation and signal absorption, often restricting communication to line-of-sight (LOS) scenarios and requiring the use of highly directional antennas. This in turn requires a radical rethinking of wireless network design. On the one hand side, such channels experience little interference, allowing for a high degree of spatial reuse and potentially simpler MAC and interference management mechanisms. On the other hand, such an environment is extremely dynamic and channels may appear and disappear over very short time intervals, in particular for mobile devices. It is essential to take these characteristics into account to turn a collection of such very high speed but brittle links into an efficient, low latency, and reliable network. This talk will highlight some of the challenges of and possible approaches for mm-wave networking.FALSEpu
Millimetric Diagnosis: Machine Learning Based Network Analysis for mm-Wave Communication
Get PDFTroubleshooting millimeter-wave (mm-wave) wireless networks is complex due to the directionality of the communication. Issues such as deafness, misaligned antennas, or blockage may severely impact network performance, and identifying them is crucial to improve network deployments. To this end, access to lower-layer information is important. However, commercial off-the-shelf mm-wave wireless devices typically do not provide such information. Even if they would, detecting effects such as deafness based on information of a single node that forms part of the network is typically hard. In this paper, we present the design and evaluation of an external sniffing device that can infer the aforementioned performance issues only using narrowband physical layer energy traces. Our sniffer does not need to decode any data, resulting in a simple but effective approach which also preserves privacy and works on encrypted networks. Our key contribution is a machine learning framework which enables automated energy trace analysis while coping with the non-stationarity of the traces. We evaluate its performance in practice using off-the-shelf wireless devices operating in the 60 GHz band. Our results show that the above framework correctly infers physical layer events in virtually all cases, thus providing valuable information to troubleshoot issues in mm-wave networks.TRUEpu
Panel: Novel Radio Solutions
No full textDuring the last years communications researchers have made great progress in all aspects of communications. Breakthroughs in optical communications, enhancements of the Internet architecture and novel data exploitation technologies, have enabled the high-capacity converged networks supporting highly diverse services. These advances have caused profound changes in the life of human beings worldwide. The perspectives for the future are of even more disruptive changes improving the quality of life our society.
As we are approaching the end of this decade, the fifth generation mobile network (5G) technology, providing mobile communication services of unprecedented quality, is on the path to become a commercial reality. This recent progress towards 5G has been enabled by a clear focus of research organizations, governmental research programs and the communications industry at large on this target. This is the critical time when researchers are starting to think about the next big steps in communications. How will people and machines communicate in the future? What kind of new communication services and data usage will impact our lives towards the end of the next decade? What will be the directions and challenges in communications and networking after 5G? What disruptive transmission technologies, network architectures, management and control schemes will allow us to take communications yet another step further?TRUEpu
Routing in Multi-Modal Underwater Networks: a Throughput-optimal Approach
Get PDFWhile acoustic signals are still the main communication means under water, other technologies are being developed, e.g., based on optical and radio-frequency electro-magnetic waves. Each technology has its own advantages and drawbacks to trade off, e.g., communication range vs. bit rate. Recently, new approaches are emerging to leverage the advantages of several underwater technologies by incorporating them in a multi-modal communication system. In this paper, we address a fundamental part of these multi-modal systems by proposing a novel routing protocol for networks of multi-modal nodes. Our protocol makes distributed optimal and fair decisions about the per-link flow, prevents bottlenecks, and allows simultaneous transmissions using multiple technologies in order to advance a packet towards its destination. We analyze the performance of our protocol via model-based simulations and compare it to benchmark results. Our results show that our protocol successfully leverages all technologies to deliver data, even in the presence of imperfect topology information.TRUEpu
Adaptive Packet Scheduling over a Wireless Channel under Constrained Jamming
Get PDFIn this work we consider the communication over a wireless link, between a sender and a receiver, being disrupted by a jammer. The objective of the sender is to transmit as much data as possible to the receiver in the most efficient way. The data is sent as the payload of packets, and becomes useless if the packet is jammed. We consider a jammer with constrained power, defined by parameters \rho and \sigma, which represent the rate at which the adversary may jam the channel, and the length of the largest burst of jams it can cause, respectively. This definition translates to the Adversarial Queuing Theory (AQT) constraints, typically used for packet arrivals.
We propose deterministic algorithms that decide the length of the packets sent in order to maximize the goodput rate; i.e., the amount of useful payload successfully transmitted over time. To do so, we first define and study a static version of the problem, which is used as a building block for the dynamic problem. We start by assuming packets of the same length and characterizing the corresponding quasi-optimal length. Then, we show that by adapting the length of the packets, the goodput rate can be improved. Hence, we develop optimal adaptive algorithms that choose the packet lengths depending on the jams that have occurred up to that point in time, in order to maximize the total
payload transmitted successfully over a period T in the presence of up to f jams.pu
Network Slicing with Flexible Mobility and QoS/QoE Support for 5G Networks
Get PDFNetwork slicing is an emerging area of research, featuring a logical arrangement of resources to operate as individual networks, thus allowing for massively customizable service and tenant requirements. The focus of this paper is to present the design of a flexible 5G architecture for network
slicing, building on SDN and NFV technologies as enablers. More specifically, we place the emphasis on techniques that provide efficient utilization of substrate resources for network slicing, ultimately optimizing network performance. The key areas of consideration in our architecture revolve around flexible service-tailored mobility, service-aware QoS/QoE control as well as network-wide orchestration.TRUEpu
On the Relationship between the Underwater Acoustic and Optical Channels
Get PDFWireless transmissions in water are mostly carried out via long-range (but low-rate) underwater acoustic communications, or short-range (but high-rate) underwater optical communications. In this paper we are interested in finding whether a statistical relationship exists between underwater acoustics and optics. Besides the theoretical interest of such relationship, predicting the quality of the optical link through acoustics is also relevant in the context of a multimodal system with both acoustics and optics. Our study is based on a large dataset acquired during the NATO ALOMEX'2015 expedition. During this experiment, we simultaneously measured several characteristics of the acoustic and optical links at multiple locations, reflecting a diversity of sea environments. Our results, show a strong correlation between the properties of the acoustic link and the reliability of optical communications. This correlation makes it possible to predict the state of the underwater optical link at a certain depth and range. Due to the complexity of the acoustic and optical channels, we could not find the source of this correlation. This work is therefore aimed to stimulate a theoretical study of the mutual properties of underwater acoustic and optical communication links. For reproducibility, we share the processed data from the experiment.pu
Electrosense: Crowdsourcing Spectrum Monitoring
Get PDFWe present Electrosense: a distributed, collaborative and low-cost wireless spectrum monitoring solution which is deployed on a large scale. The proposed framework provides tools to enable and promote a crowdsourced open spectrum monitoring platform for wide area deployments. The collected spectrum data is stored and processed in the backend which can be easily retrieved by the users through an open API. The framework also allows using various signal processing algorithms deployed on the sensors as well as in the backend. These algorithms provide statistics on spectrum usage, collaborative spectrum data decoding, help in applications like anomaly detection and localization. The goal of the demo is to introduce the framework, show the infrastructure already deployed, how to join the network and demo a few built-in applications.TRUEpu
The Impact of Processing Order on Performance: a Taxonomy of Semi-FIFO Policies
Get PDFModern network processors increasingly deal with packets that require heterogeneous processing. We consider the problem of managing a bounded size input queue buffer
where each packet requires several rounds of processing before it can be transmitted out. This to maximize the total number of successfully transmitted packets. Usually
the transmission order of the packets is induced by the processing order. However, processing order can have a significant impact on the performance of buffer management
policies even if the order of transmission is fixed. For this reason we decouple processing order from transmission order and restrict our transmission order to First-In-First-Out (FIFO) but allow for different orders of packet processing, introducing the class of such policies as Semi-FIFO. In this work, we build a taxonomy of Semi-FIFO policies and provide worst case guarantees for different processing orders. We consider various special cases and properties of Semi-FIFO policies, e.g., greedy, work-conserving, lazy, and push-out policies, and show how these properties affect performance. We generalize our results to additional constraints on the push-out mechanism designed to deal with copying cost. Further, we conduct a comprehensive simulation study that validates our results.pu
Measuring Spectrum Similarity in Distributed Radio Monitoring Systems
Get PDFThe idea of distributed spectrum monitoring with RF front-ends of a few dollars is gaining attention to capture the real-time usage of the wireless spectrum at large geographical scale. Yet the limited hardware of these nodes hinders some of the applications that could be envisioned. In this work, we exploit the fact that, because of its affordable cost, massive deployments of spectrum sensors could be foreseen in the early future, where the radio signal of one wireless transmitter is received by multiple spectrum sensors in range and connected over the public Internet. We envision that nodes in this scenario may collaboratively take decisions about which portion of the spectrum to monitor or not. A key problem for collaborative decision is to identify the conditions where the nodes receive the same spectrum data. We take an initial step in this direction, presenting a collaborative system architecture, and investigating the challenges to correlate pre-processed data in the backend, with key insights in the trade-offs in the system design in terms of network bandwidth and type of over-the-air radio signals. Our results suggest that it is feasible to determinate in the backend if two sensors are reading the same analog/digital signal in the same frequency, only sampling during 200 milliseconds and sending just 1 Kbyte of data per sensor to the backend.TRUEpu