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29 13 j 1 2 d i 1 2 1 2 j v 510642 2 2 j v 2 Z j 1 o L i 510642 K 1 L B Y b v L 1 p 433 MHz o q L l L Y y W 1 Y y q a a a l a q i d 9 s b k T V L h R 2 K v 0 9246 K l 0 8753 q 0 5 dBm H a Y q q 0 20 dBm H l o v q 1 2 kbps a M o e Z T f q Y l b k y q l W 1 q W a l y 0 n q W Q T 1 M 1 s Y r 0 9967 0 8686 k T V V z q Y l v L F y 4 b N 9 l w m w L m V 4 Q v L l L F 4 G b 1 o M i L k L doi 10 3969 j issn 1002 6819 2013 13 024 m s S126 D S A c I 1002 6819 2013 13 0182 08 l v L 433 MHz l k j Li Xiaomin Zang Ying Luo Xiwen et al Experiment of propagation characteristics based on 433MHz channel of WSN in orchid greenhouse J Transactions of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2013 29 13 182 189 in Chinese with English abstract L wireless sensor networks WSN T B m a L a a 1 F 5 R Y B t 0 a L L F A 1 4 d a j Z 5 6 v B a T a v v a v a Z a 7 10 b M S L X v 11 15 bMancuso M 5 RTD204 L v L C X v l 2013 03 06 2013 05 30 4 U0931001 S E Z 9 863 9 2011AA100704 T e l 1981 3 q 1 V Y L Z b 2 j v 2 Z j 1 o L i 510642 bEmail li xiaomin0924 b Y T 1973 o q p V V 3 1 V Y j Z b 2 j v 2 Z j 1 o L i 510642 bEmail yingzang i a A a r b Tik Leong Boon 16 2 4 GHz o ATmega 168 iDwaRF 168 9 L F y a pH i WSN bPark Dae Heon 17 L C i 4 1 e MSP430 CC2420 9 L b L j l b Rizman Z I 18 900 MHz 1 8 GHz 2 3 GHz o q 5 L Y h Y K v Y l b R 19 2 4 GHz T l T s L 3 m V K D l b P 20 Y V L Y y K L s V L 4 A 1 b X i v L 1 WSN i L Y k 1 C b D 19 22 A U S 13 l v L 433MHz l k 183 l B a a T a L V L 4 A 1 b y j a a y v a A y i L l y Y b y N A 1 v L k v y q Y V L L L 4 G b Z E k TI CC1101 o q 433 MHz 3 dBi L b l L v JTAG joint test action group g Y V Y 1 9 L USB universal serial bus PC M L C l b PC V L SMART Studio q b k TI CCDBG a L C T IOT100 x p s N a O a 7 a b k 2 j v n L j v m 1 U b v 36 m 9 m B 5 O z 28 m 4 m B 5 O 0 2 m m 1 U B 3 m O M A V P H 0 5 m b A O M B C 5 O A Wire mesh B Sun shading net C Steel pipe support m 1 v U i m Fig 1 Diagram of orchid greenhouses k 9 v 3 a v L l i B Y a Y 19 20 b Y L 1 S B 4 l L B W 1 7 m b Y V M q k Y H l RSSI received signal strength index q PLR packet loss rate N L d Y T N b V 1 U l q a a Y 3 T Y y q 9 0 a 5 a 10 a 15 a 20 dBm 5 9 10 a20 a30 Byte 3 Y 2 m 9 16 L l q T N S b V 1 L k 9 Table 1 Values of impact on radio propagation Y y Impact factor q Transmitting power dBm Packet length Byte Y Communication distance m Values 0 5 10 15 20 10 20 30 0 j34 W 2 m k Z k l W Y M L M e L Z T M e Z T 2 Z T b k 1 PC SMART Studio q q a M 1 M k 433 MHz v Y L l RSSI q b 2 MATLAB M 1 q q H q l RSSI PLR E s a v K D q M E L Y V k v L b 3 k k 433 MHz o q L 7 v 1 v L Y i y v L h b 4 k k s L a v 433 MHz L K q M 1 i y M 1 m V j 2013 M 184 y v L S e d 4 G b k s l W Y L Z T M k T s l 1 s Y 0 5 dBm q 7 a p v k 2 H q l RSSI 1 m 2 U w L b m 2 v l 1 Fig 2 RSSI in greenhouse and playground V m 2 V q 0 5 dBm H 7 k l RSSI w L v RSSI w L Z w L M o l 7 v RSSI w L o 1 A v y L Y v Y y N L d A 1 b D 19 21 23 24 Y l W 1 P R A 10nlgd 1 T P R l RSSI dBm A d l m n l y 0 b 2 0 a 5 dBm RSSI w L T 1 E V 2 b V 2 M 1 A n Table 2 Values of A and n in different environment Environment A l y 0 n 0 dBm Playground 38 114 2 223 0 dBm v Greenhouse 53 358 1 968 5 dBm Playground 46 596 2 453 5 dBm v Greenhouse 58 545 1 901 V 2 M L l i B Y q 5 dBm v M H A V 469 569 M 58 545 q 0 dBm H v H q n s Y 2 223 1 968 q M A Y v 7 n M l b v l L v K W V 1 m 2 m W k 3 F 16 L l 9 RSSI m 3 b m 3 q l Fig 3 RSSI in different distance and different transmitting power m 3 V A l f L q 4 l l RSSI 4 b H 15 m L h y h t 1 b SPSS q q RSSI Z s B s b V 3 q H RSSI S V 3 V A q 0 20 dBm H S v l RSSI o v v a A y Y i a y 18 21 23 b V 3 q H RSSI S Table 3 Standard error in different transmitting power dBm q Transmitting power S Standard error 0 3 52055 5 2 29384 10 2 34635 15 2 63294 20 2 87681 v g V T b V 4 q M 1 E B R 2 K v 0 9246 K l 0 8753 b A q 0 dBm H K v 52 763 13 l v L 433MHz l k 185 20 dBm K l 72 0523 q 0 dBm l y 0 n K v 2 205 q 10 dBm H n K l 1 698 b V 4 q RSSI B Z M 1 Table 4 Regression parameters of fitted curves in different transmitting power q Transmitting power dBm Determination coefficient R 2 Model parameter A l y 0 Environmental factor n 0 0 8963 52 763 2 205 5 0 9246 58 545 1 901 10 0 9033 65 180 1 698 15 0 8985 68 689 1 854 20 0 8753 72 0523 1 805 V 4 V q W E 1 m 4 U b N V A n E T T 2 T 3 U b A 0 0228 P T 2 1 4295P T 52 564 2 T P T q dBm A P T E R 2 0 9967 b T 2 m 4 V A A q P T 7 A P T W Q T 1 b Y V E l y 0 n q P T W 1 T 3 U R 2 0 8686 l y 0 n q P T W Q T 1 b n 0 0025 P T 2 0 0666 P T 2 1854 3 m 4 q A n 1 m Fig 4 Relationship of transmitting power between A and n T 2 a 3 1 L 1 7 m H v b T 4 U P R 0 0228 P T 2 1 4295 P T 52 564 10 0 0025 P T 2 0 0666 P T 2 1854 lgd 4 T P R l RSSI dBm P T q dBm d l m b I n 1 M M y e T n 1 8926 T 5 b P R 0 0228 P T 2 1 4295 P T 52 564 1 8926lgd 5 q q L 1 B b k M o e GFSK gauss frequency shift keying Z T q 1 2 kbps H q q q m 5 U b V m V A q L h Y q 20 15 dBm H q 7 q 10 5 0 dBm H Y q b m 5 q Y q Fig 5 Packet loss rate under different transmitting power and different transmitting distance 8 m 3 m 5 v 8 V q 0 5 dBm H v z Y b v 0 a 5 dBm q H q Y s Y 10 a20 a30 3 M 1 k b k T m 6 U b m 6 H q Fig 6 Packet loss rate at different packet length m 6 V A l RSSI v 90 dBm S RSSI q W 1 q q 5 V v Y b 433 MHz j 2013 M 186 o q a Y 1 2 kbps q H q V 10 3 M 30 3 q Y b N V w L H o q 433 MHz q H V 0 5 dBm q H V b l W Y Z T M k T s v k T 0 5 dBm q v b v l b W k L b Y V MATLAB q l 70 dBm a RSSI 70 dBm the area of deep blue meaning RSSI 90 dBm X axis the length of the greenhouse Y axis the width of the greenhouse m 7 q 5 0 dBm l w m Fig 7 Curved surface of RSSI between 5 and 0 dBm m 7 V q 0 dBm H X 0 j5 m aY 0 j10 m u RSSI v 70 dBm Y z u u 7 P Z X 20 j25 m aY 0 j10 m u 3 u RSSI l 90 dBm 7 X 15 m a20m P Z v e d 7 O Y a N L l B Y C 2 L J u b 1 q 5 0 dBm w m v T a q Y 5 dBm u 1 q 5 dBm w M L Z RSSI 80 dBm b Y u l 70 dBm a RSSI 70 dBm the area of deep blue meaning RSSI 90 dBm X axis the length of the greenhouse Y axis the width of the greenhouse m 8 q 5 0 dBm H l w L m Fig 8 Filled contour of RSSI between 5 and 0 dBm v k v A L 1 b k Z L 1 L b v W k L l b M 1 m 8 U h w L m b m 8 V A u L Z u Z 1 13 l v L 433MHz l k 187 2 m P H X U S 10 m P B u l L I C u T H v Z b q 5 dBm H v Z T RSSI u O a v 8 7 P m u W h y b m 8a M m T a Y i h y b L p 8 L l v L q V 5 4 5 dBm I n Y RSSI 0 dBm K D 4 b m 9 9 L RSSI W 1 w L m Fig 9 Comparison between caculated and measured RSSI k Y V k s 0 dBm 5 dBm 2 q V T v L q n b q 4 RSSI T 5 y v k b L q 10 V L L Y 1 p b RSSI k T m 9 U V m V A L T 9 w L o V z Q L T M t b 4 T 5 L M RE 9 b 0 dBm RE 9 0 08 W 7 5 dBm RE l 1 1 b v L Y 433 MHz o q L l L Y y W 1 Y y q a a a l a q i d 9 s b k T V 4 q 0 5 dBm H Y q b v L B H h R 2 K v 0 9246 K l 0 8753 b E y v RSSI Y d B s A q P T W l y 0 n q P T W Q T 1 b q 0 20 dBm H RSSI o v b q 9 F q L Y b k M q 1 2 kbps a Z T GFSK H q M M l M q Y l b M 9 RSSI w m w L m V 4 Q v L l a a Y v L h Y v b w m w L m V L 4 G b 8 v L F y WSN H 1 I n 5 dBm q I n Y a RSSI y 0 dBm q D 4 b k T V V z Q l q Y M L F y 4 b v y s k K k S F k I n y b V v F y 8 L Y V F x p a MAC x p F Z T WSN v K F F b 1 Yick J Mukherjee B Ghosal D Wireless sensor network survey J Computer Networks 2008 52 12 2292 2330 2 Pottie G J Kaiser W J Wireless integrated network sensors J Communications of the ACM 2000 43 5 51 59 3 L L l M 2011 4 y L M b v 2005 5 D k f L j J j 2005 9 2 232 234 Qiao Xiaojun Zhang Xin Wang Cheng et al Application of the wireless sensor network in agriculture J Transactions j 2013 M 188 of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2005 Supp 2 232 234 in Chinese with English abstract 6 f C Y i J j 2007 2 195 200 Li Li Zhang Yan e Wang Maohua et al Communication Technology for Sustainable Greenhouse Production J Transactions of the Chinese Society of Agricultural Machinery 2007 2 195 200 in Chinese with English abstract 7 Nadimi E S Jrgensen R N Blanes Vidal V et al Monitoring and classifying animal behavior using ZigBee based 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Yan X Meng X Yan Y A wireless sensor network in precision agriculture J Telkomnika 2012 10 4 788 797 14 Garcia Sanchez A Garcia Sanchez F Garcia Haro J Wireless sensor network deployment for integrating video surveillance and data monitoring in precision agriculture over distributed crops J Computers and Electronics in Agriculture 2011 75 2 288 303 15 Park D Park J Wireless sensor network based greenhouse environment monitoring and automatic control system for dew condensation prevention J Sensors 2011 11 4 3640 3651 16 Tik L B Khuan C T Palaniappan S Monitoring of an aeroponic greenhouse with a sensor network J International Journal of Computer Science and Network Security 2009 9 3 240 246 17 Park D Park J Wireless sensor network based greenhouse environment monitoring and automatic control system for dew condensation prevention J Sensors 2011 11 4 3640 3651 18 Rizman Z I Jusoff K Rais S S et al Microwave signal propagation on oil palm trees measurements and analysis J International Journal on Smart Sensing and Intelligent Systems 2011 4 3 388 401 19 R u S T 2 4GHz L l J j 2012 28 12 195 200 Guo Xiuming Zhao Chunjiang Yang Xingting et al Propagation characteristics of 2 4 GHz wireless channel at different heights in apple orchard J Transactions of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2012 28 12 195 200 in Chinese with English abstract 20 P L Z T l k J j 2010 26 6 211 215 Wen Tao Hong Tiansheng Li Zhen et al Test of wireless sensor network radio frequency signal propagation based on different node deployments in citrus orchards J Transactions of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2010 26 6 211 215 in Chinese with English abstract 21 y l B L 2 4GHz L l Y J j 2009 25 9 2 184 189 Li Siyu Gao Hongju Jiang Jianzhao Impact of antenna height on propagtion characteristics of 2 4 GHz wireless channel in wheat field J Transactions of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2009 25 Supp 2 184 189 in Chinese with English abstract 22 Ziade Y Roussel H Tabbara W et al A theoretical model of propagation in forest compared with experimental results C Seoul Korea Republic of Institute of Electrical and Electronics Engineers Inc 2005 23 D k f L j J j 2005 21 9 2 232 234 Qiao Xiaojun Zhang Xin Wang Cheng et al Application of the wireless sensor network in agriculture J Transactions of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2005 21 Supp 2 232 234 in Chinese with English abstract 24 Peng Y He U Choi J Wireless sensing and propagation characterization for smart greenhouses C Changsha China Springer Verlag 2012 13 l v L 433MHz l k 189 Experiment of propagation characteristics based on 433MHz channel of WSN in orchid greenhouse Li Xiaomin 1 2 Zang Ying 1 2 Luo Xiwen 1 2 Li Teng 1 2 Liu Yongxin 1 2 Kong Qingjun 1 2 1 College of Engineering South China Agricultural University Guangzhou 510642 China 2 Key Laboratory of Key Technology on Agricultural Machine and Equipment South China Agricultural University Ministry of Education Guangzhou 510642 China Abstract There were very few studies on the propagation characteristics of wireless sensor networks in an orchid greenhouse For deploying a wireless sensor networks system and studying the channel characteristics under orchid greenhouse the relationship between radio frequency signal propagation characteristics and radio signals influencing factors was studied with a 433MHz carrier frequency for configuring wireless sensor networks in an orchid greenhouse At first the curves of the received signal strength had less fluctuation in a playground than in a greenhouse From the contrast experiment in both greenhouse and playground the results showed that the orchid greenhouse had a great impact on the received signal strength of wireless sensor networks During the experiments the transmitting power packet length communication distance and the location of the source of the transmitting signal had changed for obtaining the received signal strength and the packet loss rate The experiments demonstrated that the relationship of the received signal strength and communication distance caused attenuation to exist according to a logarithmic model and the regression coefficient R 2 was in the range of 0 9246 and 0 8753 When the transmitting power was 0 dBm or 5 dBm the wireless signal communication success rate got higher When the transmitting power was 0 dBm or 20 dBm the received signal strength index RSSI would gain more fluctuations Furthermore when the data transmission rate was 1 2 kbps the packet length had little effect on the packet loss rate The regression analysis results demonstrated the regression parameters A and the transmitting power were quadratic relationship and it was a quadratic regression equation between the environmental factor n and transmitting power The curved surface and filled contour of RSSI were built by analyzing the data The wireless signal propagation characteristics of the orchid greenhouse environment were intuitively and comprehensively reflected Besides a model was built for calculating the received signal strength of 433 MHz in an orchid greenhouse The simplified math model was developed for the need of engineering Meantime the math model could be used for predicting the received signal strength at different transmitting powers and different communication distances by the verification experiment Finally this research could provide specific and detailed reference for a configured WSN system in orchid greenhouses Key words greenhouses wireless sensor networks experiments communication channels RF characteristics orchid 3 I W
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