ENABLING INNOVATIVE WIRELESS SOLUTIONS CROPS – WIRELESS SENSOR NETWORKS FOR SPECTRUM SENSING AND COGNITIVE COMMUNICATION

Viktoria Fodor, Mikael Skoglund (KTH) Geir Øien (NTNU) Jussi Ryynänen (Aalto) http://www.ee.kth.se/commth/projects/CROPS/

The design of spectrum sensing WSNs

• To enable new and innovative wireless solutions

• Challenge: - The large part of the radio spectrum is assigned to traditional

technologies/services (like mobile networks) - Small IMF band can not accommodate all new solutions (WiFi,

personal networks, sensor networks, device to device communication)

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• Solution: Spectrum access with cognitive radio

- Dynamic spectrum access of licensed bands - Efficient spectrum sharing in open spectrum

• Knowledge about spectrum availability is needed

• Project objective: design of spectrum sensing wireless

sensor networks - Spectrum sensing requirements - Sensor data fusion - Cooperative transmission and multihop communication - Sensing hardware design

Spectrum sensing requirements

• Selected publications:

- V. Fodor, I. Glaropoulos and L. Pescosolido, "Detecting low-power primary signals via distributed sensing to support opportunistic spectrum access," submitted to IEEE ICC, 2009.

- I. Glaropoulos, V. Fodor, "On the efficiency of distributed spectrum sensing in ad-hoc cognitive radio networks," in Proc. of ACM CoRoNet 2009, September 2009

- N. H. Mahmood, F. Yilmaz, and M.-S. Alouini, “A generalized and parameterized interference model for cognitive radio networks,” in 12th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC ’11), San Francisco, USA, June 2011.

- N. H. Mahmood, F. Yilmaz, M.-S. Alouini, and G. E. Øien, “On the Performance Analysis of Legacy Systems in the Presence of Next Generation Interference,” Submitted for publication (Journal), 2011.

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• For sensing accuracy sensors have to share information - Challenge: efficient sensing of transmitter with unknown location - Proposed solution: sensor density and cooperation requirements for

efficient sensing

• Interference level at the primary receiver have to be managed - Challenge: unknown terminal positions - Proposed solution: sum interference

models that can be used to evaluate other perf. metrics

• Result: requirements towards efficient sensing, data fusion and communication

Sensor data fusion

• The highly correlated sensor measurements have to be collected at an aggregation point or shared by the sensors - Challenge: efficiency with low computational complexity and delay - Proposed solution: New techniques for distributed source-channel coding

and quantization for orthogonal and simultaneous transmission.

• Spectrum sensor data processing is easier if the location of the transmitter is known - Challenge: source localization under spatially correlated shadowing - Proposed solution: algorithms that are robust in erroneous assumptions on

the channel parameters

• Selected publications:

- N. Wernersson, J. Karlsson and M. Skoglund, "Distributed quantizers over noisy channels," IEEE Transactions on Communications, June 2009.

- N. Wernersson, M. Skoglund and T. Ramstad, "Polynomial based analog source-channel codes," IEEE Transactions on Communications, September 2009.

- N. Wernersson and M. Skoglund, "Nonlinear coding and estimation for correlated data in wireless sensor networks," IEEE Transactions on Communications, October 2009.

- J. Karlsson and M. Skoglund, "Optimized low-delay source-channel-relay mappings," IEEE Transactions on Communications, May 2010. - John T. Flåm, Ghassan M. Kraidy and Daniel J. Ryan: “Using a Sensor Network to Localize a Source under Spatially Correlated

Shadowing”, IEEE VTC Taipei 2010. - John T. Flåm, Joakim Jaldén and Saikat Chatterjee: “Gaussian mixture modeling for source localization”, IEEE ICASSP 2011.

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Cooperative transmission

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• Sensor and relay nodes need to collaborate in the transmission of data to improve energy-efficiency

- Challenge: Joint optimization gives gains, but can be complex and sensitive to design assumptions

- Proposed solution: New collaborative transmission protocols based on relaying. Improved performance and significant energy-saving demonstrated

• In case of simultaneous transmissions the power allocation has to be fair and efficient

- Challenge: computational complexity and signaling overhead has to be low, interference has to be maintained

- Proposed solution: Distributed power allocation based on novel utility functions

7/4/2011

• Selected publications: - S. Yao and M. Skoglund, "Hybrid digital-analog relaying for cooperative transmission over slow fading channels," IEEE

Transactions on Information Theory, March 2009

- M. Khormuji and M. Skoglund, "On instantaneous relaying," IEEE Transactions on Information Theory, vol. 56, no. 7, pp. 3378-3394, July 2010.

- J. Karlsson and M. Skoglund, "Design and performance of optimized relay mappings," IEEE Transactions on Communications, vol. 58, no. 9, pp. 2718-2724, September 2010.

- N. H. Mahmood, U. Salim, G. E. Øien, “Relative Rate Utility based Distributed Power Allocation Algorithm for Cognitive Radio Network,” Poster presented in 2011 IEEE Communication Theory Workshop (CTW’11), Sitges, Spain, June 2011.

Networking for spectrum sensing

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• Routing for optimum overall energy efficiency to increase network lifetime - Challenge: existing solutions are too complex (NP-hard) - Proposed solution: adaptive routing and transmission control heuristics

based on novel utility function

• Applying cooperative transmission techniques in mesh networks - Challenge: cooperative transmission may increase interference in the

networks - Proposed solution: co-optimized

relaying and channel access scheme

• Selected publications:

- L. Yin, C. Wang, and G. E. Øien, “An Energy-Efficient Routing Protocol for Event-Driven Dense Wireless Sensor Networks,” Springer International Journal of Wireless Information Networks, 2009 (invited paper).

- C. Wang, L. Yin, and G. E. Øien, "Energy-Efficient Route Configuration for Adaptive MPSK-Based Wireless Sensor Networks,” EURASIP Journal of Wireless Communications and Networking, 2011.

- Liping Wang, Viktoria Fodor, Mikael Skoglund, Using cooperative transmission in wireless Multihop Networks, in Proc. of IEEE International Symposium On Personal, Indoor and Mobile Radio Communications, September 2009

- Liping Wang, Viktoria Fodor, Cooperative geographic routing in wireless mesh networks, in Proc. of IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh Networking (MeshTech), November 2010

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Sensing radio HW design • Sensing HW needs to be able to sense narrow band channels over a wide

spectrum range - Challenge:

• Radio HW capable of receiving in broad frequency range does not exist

- Proposed solution: CROPS implementation of WB synthesizer

• Outperforms recently proposed solutions considering tuning range, energy consumption and noise

• 12th most downloaded paper in IEEE Aug. 2010

• 2 patent applications • Selected publications:

- A. Immonen, A. Pärssinen, S. Kiminki, V. Hirvisalo, M. Talonen and J. Ryynänen, "A Reconfigurable Multi-standard Radio Platform", International Workshop on Energy Efficient and Reconfigurable Tran-sceivers, September, 2010

- L. Xu, K. Stadius, and J. Ryynänen, "A wide-band digitally controlled ring oscillator," in proc Int. Symp. Circuits Syst., May 2010, pp. 1983-1986.

- L. Xu, S. Lindfor, K. Stadius and J. Ryynänen, "A 2.4-GHz low-power all-digital phase-locked loop," IEEE J. Solid-State Circuits, vol. 45, no. 8, pp. 1513-1521, Aug. 2010.

Viktoria Fodor – Nordite, June 2011 7

High Linearity Receiver ( SENDORA project)

Wideband ADPLL ( CROPS project)

Algorithm HW Implementation ( SENDORA project)

Hardware Description Methods for System Development

(CROPS project)

Relevance • Scientific content

- New insights into the design of energy-efficient wireless sensor networks

- With application to spectrum sensing

• Collaboration

- New highly successful Nordic research collaboration that would not have happened otherwise

• High volume of research results and publications

• Visits and co-authored papers

• Several graduated PhD’s

• Spin-off projects, e.g. the EU/Fp7 projects “SENDORA”

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Exploitation

• What could be exploited by industry now?

- The concepts of cooperative sensing and transmission

- New wireless sensor network design principles and applications

- Improved spectrum sensing HW for opportunistic spectrum sharing (2 patent applications)

• What steps are missing to make the results available for the industry?

- Some of our results need to be tested in more realistic practical scenarios

- Some of our suggested schemes do not fit present standards

• What kind of partners would we need for this?

- Telecom (Ericsson, Telenor)

- Industrial automation (ABB)

- System integrators and sensor developers

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