8th International Workshop on Wireless Network Measurements - Program

Time Session

Friday, May 18

09:00-09:30 Opening and Award Ceremony
09:30-10:15 Keynote #1: Listening while Talking: Measuring Interference in Unlicensed and White-Space Bands using Half-Duplex Radios
10:15-10:40 Break
10:40-11:30 Experimental Measurements and Results
11:30-12:20 Experimentally-driven Design and Research
12:20-13:30 Lunch
13:30-14:15 Keynote #2: Rapid Prototyping of Next Generation Networks
14:15-15:30 Experimental Methodologies and Tools

Friday, May 18

09:00 - 09:30

Opening and Award Ceremony

Workshop chairs

09:30 - 10:15

Keynote #1: Listening while Talking: Measuring Interference in Unlicensed and White-Space Bands using Half-Duplex Radios

D. Leith, Hamilton Institute

10:15 - 10:40

Break

10:40 - 11:30

Experimental Measurements and Results

A Comparison Between One-Way Delays in Operating HSPA and LTE Networks
Markus Laner (Vienna University of Technology, Austria); Philipp Svoboda (Vienna University of Technology, Austria); Peter Romirer-Maierhofer (Telecommunications Research Center Vienna (ftw.), Austria); Navid Nikaein (Eurecom, France); Fabio Ricciato (Universitá del Salento & Telecommunications Research Center Vienna (FTW), Italy); Markus Rupp (Vienna University of Technology, Austria)
The detailed understanding of packet delays in modern wireless networks is crucial to optimize applications and protocols. We conducted high precision latency measurements in operational LTE and HSPA networks, deploying a hybrid approach of active probing and withe-box testing. It allowed us to separately assess the one-way delay contributions of the radio access network and the core network for both technologies. The results show that LTE outperforms HSPA in the case of medium to high data rates. However, due to differences in the radio access procedures, the HSPA uplink connection offers lower delay for specific traffic patterns. A comparison between our measurement results and the requirements for delay sensitive applications exhibits that LTE is not (yet) the generally preferable technology. Hence, further optimizations of the LTE scheduling and resource allocation policies are required to fully exhaust all feasible latency improvements.
Experimental Investigation of Coexistence Interference in Multi-Radio 802.11 Networks
Arsham Farshad (The University of Edinburgh, United Kingdom); Mahesh K Marina (The University of Edinburgh, United Kingdom); Francisco Javier Garcia (Agilent Technologies & Visiting Prof. Strathclyde University, United Kingdom)
Using multiple interfaces in a wireless mesh node for improved wireless access raises practical problems that make achieving high performance connections with a small form factor mesh router challenging. Our experimental study focuses on investigating factors affecting the antenna proximity and in consequence the router node's dimension. Results show that for high transmission rate minimum 17cm inter-antenna separation is required to avoid throughput degradation even when interfaces are configured to use channels in different bands. Use polarization diversity can bring down this requirement to as low as 3 cm. In same band configuration, polarization diversity can reduce the node's dimensions, improve the maximum achievable rate for almost four times and reduce the number of required channel separation to two channels in remedy ACI effects. Our microscopic investigation of MAC behavior in presence of ACI shows that ACI related performance degradation can be related directly to 802.11 MAC operation.

11:30 - 12:20

Experimentally-driven Design and Research

Efficient Cooperative Relaying in Wireless Multi-Hop Networks with Commodity WiFi Hardware
Tobias Volkhausen (University of Paderborn, Germany); Kornelius Dridger, Jr. (University of Paderborn, Germany); Hermann S Lichte (Net Mobile AG, Germany); Holger Karl (University of Paderborn, Germany)
In wireless multi-hop networks, cooperative relaying exploits temporal and spatial diversity by additionally transmitting via a relay node and then combining direct and relay transmissions at the receiver. While such relaying improves packet error rates, it also costs an extra transmission. Along multi-hop paths, there often are nodes that can be a relay for multiple consecutive transmissions. This allows such a relay to transmit only once rather than on each individual hop along the routing path. We show by simulations that cooperative relaying is more efficient in multi-hop networks than in isolated three-node configurations. We compare our simulation to experimental results by implementing our multi-hop cooperation protocol on commodity Wi-Fi hardware. The appeal of using Wi-Fi is its wide availability. However, today's devices were not designed with cooperation protocols in mind. We explain the necessary steps to implement wireless cooperation protocols, using our multi-hop cooperation protocol as an example.
Should We Use the Default Protocol Settings for Networks of Constrained Devices?
August Betzler (Universitat Politècnica de Catalunya (UPC), Spain); Carles Gomez (UPC, Spain); Ilker Demirkol (Universitat Politecnica de Catalunya & i2CAT Foundation, Spain); Josep Paradells (UPC, Spain)
Constrained devices will play a crucial role in the Internet of Things. These devices use communication technologies which often support the formation of wireless multihop topologies. Therefore, end-to-end data transfer involves the collaboration of multiple protocol layers. However, the settings and mechanisms used in a specific layer affect performance of the others. In this paper, we assess a set of crucial network design criteria for potential MAC layer, network layer and transport layer protocols for networks of constrained devices. We evaluate the default and alternative settings and mechanisms for these protocols on a 60-node testbed. The experiments show how performance can be improved significantly by using different settings and mechanisms from the default ones.

12:20 - 13:30

Lunch

13:30 - 14:15

Keynote #2: Rapid Prototyping of Next Generation Networks

Nico Bayer, Telekom Innovation Labs

14:15 - 15:30

Experimental Methodologies and Tools

Energino: An Hardware and Software Solution for Energy Consumption Monitoring
Karina Mabell Gomez (Create-Net & The University of Trento, Italy); Roberto Riggio (Create-Net, Italy); Tinku Rasheed (Create-Net Research, Italy); Daniele Miorandi (Create-Net, Italy); Fabrizio Granelli (University of Trento, Italy)
In this paper we propose a scalable hardware and software solution for energy consumption monitoring, to the best of our knoledge there are no such tools available for the researhc community. We release both the hardware schematics and the software with a permissive license in order to encourage the research community to use and extend it
On the Feasibility of Measuring the Internet Through Smartphone-based Crowdsourcing
Adriano Faggiani (University of Pisa, Italy); Enrico Gregori (CNR-IIT, Italy); Luciano Lenzini (University of Pisa, Italy); Simone Mainardi (University of Pisa & Italian National Research Council, Italy); Alessio Vecchio (University of Pisa, Italy)
The large base of Internet-enabled smartphones provides an excellent opportunity for a fine-grained observation of the structure of the Internet and a quantitative evaluation of its characteristics. Smartphones can operate as active mobile monitors and, coordinated by a central entity, they can probe the network on a local scale. Then the results produced by a large number of participants can be merged to obtain a detailed graph of the Internet. Besides the design of the measurement framework, this paper describes the implementation and validation of a traceroute-like tool that is compatible with the Android platform. This confirms that smartphone-based crowdsourcing of network properties can be a viable strategy.
A Benchmark for Channel Assignment Algorithms in Wireless Testbeds
Felix Juraschek (Freie Universität Berlin, Germany); Simon Seif (Freie Universität Berlin, Germany); Mesut Günes (FU Berlin, Germany); Bastian Blywis (Freie Universität Berlin, Germany)
Channel assignment for wireless mesh networks has been proven efficient to increase the network performance by decreasing the interference of simultaneous transmissions. Many algorithms have been proposed, however, a meaningful performance comparison is difficult. The main reasons are that different experimentation environments and performance metrics are used for their evaluation. Thus, finding a universal methodology for the performance evaluation that ensures comparability is complicated. In this paper, we close this gap with a methodology for the performance evaluation of channel assignment algorithms in wireless testbeds. We developed domain-specific performance metrics that express the decrease of network-wide interference. Using these metrics, we developed benchmarking scenarios for performance measurements in wireless testbeds. We present the benchmarking results of a distributed link-based channel assignment algorithm and compare the results to a random-based algorithm and a single channel network. The evaluation was run on the DES-Testbed with 128 nodes at the Freie Universität Berlin.