工場内無線LAN システム

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1 25 Local Area Radio Network in Factories Tsutayuki Shibata, Naoyuki Yamada, Yoshikazu Asano LAN LAN LAN CEllular Local Area Radio Network : CELARN CELARN 1 CELARN Abstract A need for real-time data transmission to forklifts and Autonomous Guided Vehicles (AGVs) in factories has been increasing. Local Area Radio Network (LARN) can fulfill this need. In factory environment, however, there are many machines which obstruct the radio wave propagation. This paper proposes CEllular Local Area Radio Network (CELARN), which has good transmission performance in such factory environment. CELARN consists of some radio networks and a wired network which integrates the radio networks. The base stations are connected to one another by the wired network in a logical ring. A data-frame makes the rounds of the base stations to transmit data. Moreover, the data-frame behaves as a token of the common radio control channel to prevent collisions. The transmission performance of the CELARN was analyzed for its application to car manufacturing factories. The analysis shows that the CELARN has good transmission delay performance even in such inferior environment. LAN R&D Vol. 29 No. 3 ( )

In factory environment, however, there are many machines which obstruct the radio wave propagation.

2 26 ( Automonous Guided Vehicle AGV ) LAN LAN LAN LAN LAN LAN LAN LAN AGV ( MS ) LAN MS MS MS ( ) ( BS ) MS MS MS MS MS LAN 2 BS MS MS MS LAN LAN LAN 1 2 BS MS MS BS MS ( ) ( ) ( 4.47µV ) 1 R&D Vol. 29 No. 3 ( )

3 27 LAN 1 LAN BS MS LAN LAN ( CEllular Local Area Radio Network CELARN ) CELARN CELARN ( BS ) BS 2 BS (MS) Architecture of CELARN. BS BS BS MS BS MS BS 1 1-persistent CSMA BS BS BS MS MS MS MS BS CELARN R&D Vol. 29 No. 3 ( )

4 28 BS MS CELARN BS MS BS MS BS BS i BS ( BSi ) i k MS ( MSik ) j BS ( BSj ) j l MS ( MSjl ) LAN MSik BSi BSi BSj BSj MSjlLAN MSik BSi ( 1-persistent CSMA ) BSi ACKnowledge Non-ACKnowledge BSi MS MS BSBSjBSi Communication procedure. R&D Vol. 29 No. 3 ( )

BSi ( 1-persistent CSMA ) BSi ACKnowledge Non-ACKnowledge BSi MS

5 29 MS j MS MS MSjl ACK NACK LAN LAN CELARN 1200MHz ( VCXO ) 16kbps NRZ MSK 10dBm 1200MHz LNA 2 Specifications of pilot system. Frequency MHz ( for BS transmitting ) MHz ( for MS transmitting ) Channel spacing 50kHz Frequency tolerance 2ppm Bit rate 16kbps ( radio network ) 300kbps ( wired network ) Modulation MSK Demodulation Limiter-discriminator Output power 10dBm Reception sensitivity 104dBm ( BER : 10 2 ) Antenna Inverse-F type ( for MS ) 1/4 λ monopole ( for BS ) Diversity reception 2 branch antenna selection Dimenstion ( W D H ) mm ( MS ) mm ( BS ) Block diagram of pilot system. R&D Vol. 29 No. 3 ( )

300kbps ( wired network ) Modulation MSK Demodulation Limiter-discriminator Output power 10dBm Reception sensitivity 104dBm ( BER : 10 2 ) Antenna Inverse-F type (

6 30 8bit MPU 32Kbyte ROM RAMMPSC ( Multi Protocol Serial Controller ) ROM BS CRC-CCITT ( X 16 X 12 X 5 1 ) ( Automatic Repeat request : ARQ ) ARQ BS MS LAN CELARN km 3 ( ) 1200MHz 2.1m Photograph of pilot system. ( Left side : MS, Right side : BS ) Photograph of radio propagation measuring vehicle. R&D Vol. 29 No. 3 ( )

CELARN 3 14 3.6km 3 ( ) 1200MHz 2.1m Photograph of pilot system.

7 31 12mm 3 ( 1MHz ) 2 ( ) ( ) P re [dbm] = P 0 10αlogr (1) αp 0 1m (1) ( ) 3 70dBm 1m dBm LAN Average received signal strength versus transmission distance. Ratio of cumulative probability distributions of received signal strength. R&D Vol. 29 No. 3 ( )

5 70dBm LAN Average received signal strength versus transmission

8 32 LAN BS MS MS P ave P ave = 1 P p 2πr dr (2) πr 2 0 r L p P p P p P b P P = 1 r L p i = 1 1 P b Γ (3) Γ Γ (1) Γ [db] = P re N 0 (4) CELARN MS MS ( ) D MSMS D 3 MS BS D 1 BS BS D 2 BSMS D 3 MS BS S 1 τ 1 BS BSS 2 τ 2 BS MS S 3 τ 3 D a D b MS BS1-persistent CSMA BS BS BS MS D S 1 S 2 S 3 S 1 D 1 S 1 1-persistentCSMA ng ( 1 + ng)e-ng S 1 = (1 P p ) (1 P c ) (5) ng + e -ng G G a G b D 1 D 1 = τ d + L p R 1 + ng S 1 1 L c R 1 + τ 1 + τ d + L p R 1 + τ h (6) τ d MS BS τ d = 1 ng L p (7) 2 ng + e -ng R l D 2 D 3 BS TBS m T MS BS R 1 S 1 mt R&D Vol. 29 No. 3 ( )

2 S 3 S 1 D 1 S 1 1-persistentCSMA ng ( 1 + ng)e-ng S 1 = (1 P p ) (1 P c ) (5) ng + e -ng G G a G b D 1 D 1 = τ d + L p R 1 + ng S 1 1 L c R

9 33 R 1 S 1 mt ( G a /G ) R 1 S 1 mt ( G b /G ) MS m BS MS Q w Q r Q wa = R 1 S 1 m T Ga m G 2 (8) Q wb = R 1 S m T Gb m 1 (9) G 2 Q ra = 0 (10) Q rb = R 1 S 1 m T Gb (11) G "a" "b" T T = Q wa + Q wb R 2 + Lc R 3 + τ 2 (12) D 2 BS m T/2 (2m 1) T (2m 1) T D 2 = mt + = (13) 2 2 D 3 MS Parameters used for performance analysis. Item Symbol Value Number of BS m 10 Number of MS per cell n 10 Bit rate in radio network Rr 16 (kbps) Bit rate in wired network Rc 400 (kbps) Signal degradation factor α 4.6 Received signal power factor P (dbm) Noise power N (dbm) Data packet length Ld 1024 (bit) Control packet length Lc 100 (bit) Process time of re-transmission in radio network Process time of re-transmission in wired network τr τc 30 (msec) 20 (sec) Average delay for transmitting halt in radio network τh 2 (sec) Average speed of each MS ν 10 (km / h) Traffic G Time period of transmission data-frame among BSs T Average volume of data on downlink channel Qrb D 3 = Lc R 3 + Q rb 2R 3 1 P p + Q rb R 3 + τ 3 + Q rb 2R 3 P p + τ h (14) CELARN MS MS Packet error rate versus cell radius. ( Packet length : 1024 bit] ) R&D Vol. 29 No. 3 ( )

Item Symbol Value Number of BS m 10 Number of MS per cell n 10 Bit rate in radio network Rr 16 (kbps) Bit rate in wired network Rc 400 (kbps) Signal degradation factor α 4.

10 m 60m LAN CELARN ( ) CELARN CELARN BS MS ( ) LAN MS CELARN CELARN CELARN 60m Time delay performance versus traffic. ( Packet error rare : ) Transmission delay versus cell radius. R&D Vol. 29 No. 3 ( )

11 35 1), (1985), 2) Marcus, M. J. : "Regulatory policy consideration for radio local area networks", IEEE Commun. Mag., -7(1987), 95 3) McKenny, P., et al. : "Physical- and link-layer Modeling of packet-radio network performance", IEEE J. Sel. Areas Commun., -1(1991), 59 4) Sinha, R., et al. : "Mobile packet radio networks : state-ofthe-art", IEEE Commun. Mag., -3(1985), 53 5), (1989), 6) 1200MHz (RCR STD-16), (1989), 7), 2 : " LAN ",, IN91-116(1991), 19 8), 3 : "2GHz ",, RCS90-40(1990), 79 9) Kleinlock, L., et al. : "Packet switching in radio channels: part I- Carrier sense multiple-access modes and their throughput-delay characteristics", IEEE Trans. Commun., -12(1975), ) :, (1985), 11) :, (1990), 12), 3 : " LAN ",, IN91-117(1991), 25 13) Akaiwa, Y. : "Antenna selection diversity for framed digital signal transmission in mobile radio channel", in Proc. of the 39th IEEE Vehicular Technol. Conf., (1989), ), 2 : " ", 1991, B- 398(1991), LAN 1962 LAN 1957 LAN R&D Vol. 29 No. 3 ( )

: "Mobile packet radio networks : state-ofthe-art", IEEE Commun. Mag.

Vol.53 No (July 2012) EV ITS 1,a) , EV 1 EV ITS EV ITS EV EV EV Development and Evaluation of ITS Information Commu

Vol.53 No (July 2012) EV ITS 1,a) , EV 1 EV ITS EV ITS EV EV EV Development and Evaluation of ITS Information Commu EVITS 1,a) 2 2 2011 10 21, 2012 4 2 EV 1 EV ITS EV ITS EV EV EV Development and Evaluation of ITS Information Communication System for Electric Vehicle Yuriko Hattori 1,a) Tomokazu Shimoda 2 Masayoshi