THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS TECHNICAL REPORT OF IEICE. 565-0871 1 5 E-mail: {s-kasihr, wakamiya, murata}@ist.osaka-u.ac.jp PC 70% Design, implementation, and evaluation of a synchronization-based Abstract data gathering scheme for sensor networks in buildings Shuntaro KASHIHARA, Naoki WAKAMIYA, and Masayuki MURATA Graduate School of Information Science and Technology, Osaka University 1 5 Yamadaoka, Suita, Osaka 565 0871, Japan E-mail: {s-kasihr, wakamiya, murata}@ist.osaka-u.ac.jp In this paper, we propose a data gathering scheme for a wireless sensor network constructed in a building. Due to shadowing and fading, radio communications in a building become unstable and unreliable. Our system consists of parent nodes, which have power supply and a wired connection to a monitoring PC, and child nodes, which operate on a battery and have the capability of radio communications. In our scheme, a sensor node chooses the next-hop node among a parent node, which collects sensor information from sensor nodes in its vicinity, and child nodes which provide a path to a parent node, in accordance with the stability of radio communications. We confirmed that stable data gathering with more than 70% gathering rate can be accomplished in a sensor network in the unstable environments. Key words Sensor networks, Data gathering, Synchronization 1. [1] 1
Host PC 1 PC [2] LAN PC ( 1) MAC 2 3 4 2. 2. 1 1 ε δ SLEEP i ε δi SLEEP ε 1 0 δj SLEEP δ j δi 1 0 1 0 1 0 1 0 1 0 2 ε SLEEP ε δj SLEEP i φ j i φ PC 5 2. 2 0 1 1 5 1 ɛ ( 2)ɛ 1 δ 2
c + j 3 = li l j c k = li + lk j l j i l i lk c i = l i 2. 3 δ 1 5 5 5 20 1 ɛ 0.3 40% 2. 2 1 3 i l i j i l j k i l k i c i l i j c j = l i + l j k c k = l i + l k MAC IEEE 802.15.4 k 4 8 bit p C(S, R, Cp) C (S, R, C p) = Round((S+(1 R Rmin )) 10)+C p(1) R max R min S 5 R i i R max R min C p p 255 C p = 0 (1) 20 10 1 2. 3 δ i δ i δ i ɛ R max R min (R max R i) (2) ɛ 0 < δ i < ɛ 2. 4 ɛ N ɛ ɛn ɛn 1 PC N 3
Host PC synchronization hub 4 6 ( ) 5 m 100 B9 B8 B7 B6 C5 C4 C3 C2 C1 C0 C9 C8 C7 C6 5 m gathering rate[%] 80 60 40 20 5 ( ) 0 0 5 10 15 20 25 30 35 40 45 50 cycle number N o < N ɛn o N o N 3. ( 4) PC [7] MAC IEEE 802.15.4 (2.4GHz, non-beacon mode) 5m RS-232C PC PC 20 ɛ 0.3 3. 1 5 1 30 5 m 80 cm 7 ( ) 6 7 6 C9 180 C8 7 20 180 9 0% 4
delete 8 ( ) 10 ( ) 150 200 250 300 350 400 450 500 beacon signal single hop signal multi hop signal 9 ( ) 200 250 300 350 400 450 500 550 beacon signal single hop signal multi hop signal 1.2 /m 2 77.7% 42.4% 7 3. 2 8 0 cm 100 cm 9 250 400 400 10 11 230 5 11 ( ) barrier 12 ( ) 350 400 450 500 550 600 650 700 beacon signal single hop signal multi hop signal 13 ( ) 255 500 5
B9 B8 B9 B8 B7 B6 B7 B6 2 1 1 14 ( ) 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 1 beacon signal 1 single hop signal 1 multi hop signal 3. 3 12 13 420 670 3. 4 14 1 15 2 16 1 B9 2 2 1 6 ( ɛ = 20 0.3) PC 15 16 91.5% 4. PC 91.5% 21 COE ( ) (A)(2)16200003 15 16 ( 1) B9 B8 B7 B6 2 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 2 beacon signal 2 single hop signal 2 multi hop signal ( 2) [1] I. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci, Wireless sensor networks: A survey, Computer Networks (Elsevier) journal, vol.38, pp.393 422, March 2002. [2] N. Wakamiya and M. Murata, Scalable and robust scheme for data fusion in sensor networks, Proceedings of International Workshop on Biologically Inspired Approaches to Advanced Information Technology (Bio-ADIT), pp.112 127, Jan. 2004. [3] R. E. Mirollo and S. H. Strogatz, Synchronization of pulse-coupled biological oscillators, Society for Industrial and Applied Mathematics Journal on Applied Mathematics, vol.50, pp.1645 1662, Dec. 1990. [4] X. Guardiola, A. Diaz-Guilera, M. Llas, and C. Perez, Synchronization, diversity, and topology of networks of integrate and fire oscillators, The America Physical Society Physical Review E, vol.62, pp.5565 5569, Oct. 2000. [5] M. B. H. Rhouma and H. Frigui, Self-organization of pulsecoupled oscillators with application to clustering, IEEE Transaction on Pattern Analysis and Machine Intelligence, vol.23, pp.180 195, Feb. 2001. [6] I. Wokoma, I. Liabotis, O. Prnjat, L. Sacks, and I. Marshall, A weakly coupled adaptive gossip protocol for application level active networks, Proceedings of IEEE 3rd International Workshop on Policies for Distributed System and Networks - Policy 2002, pp.244 247, June 2002. [7] Ubiquitous Device. available at URL: http://www. okitechno-c.co.jp/tech/wireless/zigbee.html. 6