Vidyut: exploiting power line infrastructure for enterprise wireless networks

ABSTRACT

Global synchronization across time and frequency domains significantly benefits wireless communications. Multi-Cell (Network) MIMO, interference alignment solutions, opportunistic routing techniques in ad-hoc networks, OFDMA etc. all necessitate synchronization in either time or frequency domain or both. This paper presents sysname, a system that exploits the easily accessible and ubiquitous power line infrastructure to achieve synchronization in time and frequency domains across nodes distributed beyond a single-collision domain. sysname uses the power lines to transmit a reference frequency tone to which each node locks its frequency. sysname exploits the steady periodicity of delivered power signal itself to synchronize distributed nodes in time.

We validate the extent of sysname's synchronization and evaluate its effectiveness. We verify sysname's suitability for wireless applications such as OFDMA and multi-cell MIMO by validating the benefits of global synchronization in an enterprise wireless network. Our experiments show a throughput gain of 8.2x over MegaMIMO, 7x over NemoX and 2.5x over OFDMA systems.

Enterprise wireless networks are supported by an Ethernet backbone. Researchers have been exploring techniques over the backbone to enable and assist in improving the performance of the wireless networks. Recent work also showed the benefit of sharing information in the air between the nodes to enable higher performance of the network. Even sharing information as little as synchronization information has been demonstrated to open new avenues (such as MU-MIMO, Physical Network Coding, Opportunistic routing, etc.) for the wireless networks to enhance its performance. However, another medium shared by majority of the nodes in the enterprise network - the power line infrastructure - has been largely left untapped to assist the wireless network. While the power lines are noisy and have a frequency selective transmission characteristic, its uniqueness is that its range can extend beyond that over air while it is unburdened by switching and other responsibilities of the Ethernet backbone. This paper poses the following question: How best to exploit the opportunity presented by the power lines to further enhance enterprise wireless networks?

The key contributions of this paper are the following: Identify and demonstrate the feasibility of utilizing power lines as a medium to achieve synchronization (in time and frequency domains) between nodes in the network; Demonstrate the scalability of this technique by achieving synchronization between nodes beyond the transmission range of any of the individual nodes. The paper presents empirical results pertaining to the accuracy of synchronization and the benefit of the proposed synchronization method to existing distributed wireless techniques by virtue of extension across multiple collision domains.

References

1. Analog Devices. AD9511:1.2 GHz Clock Distribution IC,PLL Core, Dividers, Delay Adjust, Five Outputs. Rev. A.
2. Balan, H. V., Rogalin, R., Michaloliakos, A., Psounis, K., and Caire, G. Airsync: Enabling distributed multiuser mimo with full spatial multiplexing. CoRR abs/1205.6862 (2012).
3. Cheng, X., Cao, R., and Yang, L. Relay-aided amplify-and-forward powerline communications. Smart Grid, IEEE Transactions on 4, 1 (March 2013), 265--272.
4. Cohn, G., Stuntebeck, E., Pandey, J., Otis, B., Abowd, G. D., and Patel, S. N. Snupi: Sensor nodes utilizing powerline infrastructure. In UBICOMP (2010), ACM, pp. 159--168.
5. Galli, S., Scaglione, A., and Wang, Z. For the grid and through the grid: The role of power line communications in the smart grid. Proc. IEEE (June 2011), 998--1027.
6. Gungor, V., Sahin, D., Kocak, T., Ergut, S., Buccella, C., Cecati, C., and Hancke, G. Smart grid technologies: Communication technologies and standards. Industrial Informatics, IEEE Trans. on (2011).
7. Ha, J. Y., Jeon, J., Lee, K., Heo, J., Kim, N., Kim, S. M., Kwon, W.-H., and jin Jung, B. Design and implementation of convergence sub-layer for a heterogeneous home network. In ISPLC (2007).
8. Kuhn, M., Berger, S., Hammerstrom, I., and Wittneben, A. Power line enhanced cooperative wireless communications. Sel. Areas in Comm., IEEE J. (2006).
9. Lai, S., and Messier, G. The wireless/power-line diversity channel. In IEEE Int. Conf. on Comm.(ICC) (2010).
10. Lai, S., and Messier, G. Using the wireless and plc channels for diversity. Communications, IEEE Transactions on (2012).
11. Lin, Y.-J., Latchman, H., Lee, M., and Katar, S. A power line communication network infrastructure for the smart home. Wireless Communications, IEEE (2002).
12. Maxim Integrated. MAX2828/MAX2829: Single/Dual Band 802.11a/b/g World-Band Transceiver ICs. Rev. 0.
13. Meng, H., Guan, Y., and Chen, S. Modeling and analysis of noise effects on broadband power-line communications. Power Del., IEEE Trans. 20, 2 (April 2005), 630--637.
14. Rahul, H., Hassanieh, H., and Katabi, D. Sourcesync: a distributed wireless architecture for exploiting sender diversity. In SIGCOMM (2010), ACM, pp. 171--182.
15. Rahul, H., Kumar, S., and Katabi, D. MegaMIMO: Scaling Wireless Capacity with User Demands. In SIGCOMM (2012), ACM.
16. Rowe, A., Gupta, V., and Rajkumar, R. R. Low-power clock synchronization using electromagnetic energy radiating from ac power lines. In SENSYS (2009), ACM, pp. 211--224.
17. Schwager, A. An overview of the homeplug av2 technology. Journal of Electrical and Computer Engineering 2013 (2013).
18. Tan, B., and Thompson, J. Relay transmission protocols for in-door powerline communications networks. In IEEE Int. Conf. on Comm. Work. (ICC) (2011).
19. Tlich, M., Zeddam, A., Moulin, F., and Gauthier, F. Indoor power-line communications channel characterization up to 100 mhz;part i: One-parameter deterministic model. Power Del., IEEE Trans. (July 2008), 1392--1401.
20. Tlich, M., Zeddam, A., Moulin, F., and Gauthier, F. Indoor power-line communications channel characterization up to 100 mhz;part ii: Time-frequency analysis. Power Del., IEEE Trans. (July 2008), 1402--1409.
21. Zhang, X., Sundaresan, K., Khojastepour, M. A. A., Rangarajan, S., and Shin, K. G. Nemox: Scalable network mimo for wireless networks. In MOBICOM (2013), ACM, pp. 453--464.
22. Zimmermann, M., and Dostert, K. Analysis and modeling of impulsive noise in broad-band powerline communications. Electromagnetic Compatibility, IEEE Trans. (Feb 2002), 249--258.

Index Terms

• Hardware

  • Communication hardware, interfaces and storage

• Networks