WIRELESS PERSONAL AREA NETWORKS (WPANs) BLUETOOTH Ian F. Akyildiz Broadband & Wireless Networking Laboratory School of Electrical and Computer Engineering Georgia Institute of Technology Tel: 404 -894 -5141; Fax: 404 -894 -7883 Email: ian@ece. gatech. edu Web: http: //www. ece. gatech. edu/research/labs/bwn
WPAN: INTRODUCTION n A WPAN (Wireless PAN) is a short-distance wireless network specifically designed to supportable and mobile computing devices such as PCs, PDAs, wireless printers and storage devices, cell phones, pagers, settop boxes, and a variety of consumer electronics equipment. n Bluetooth is an example of a wireless PAN that allows devices within close proximity to join together in ad hoc wireless networks in order to exchange information. n Many cell phones have two radio interfaces-one for the cellular network and one for PAN connections. IFA’ 2004 2
WPAN n WPANs such as Bluetooth provide the bandwidth and convenience to make data exchange practical for mobile devices such as palm computers. n Bluetooth overcomes many of the complications of other mobile data systems such as cellular packet data systems. . . n The reach of a PAN is typically a few meters. IFA’ 2004 3
WPAN n A Bluetooth PAN is also called a piconet, and is composed of up to 8 active devices in a master-slave relationship (up to 255 devices can be connected in 'parked' mode). n The first Bluetooth device in the piconet is the master, and all other devices are slaves that communicate with the master. n A piconet typically has a range of 10 meters, although ranges of up to 100 meters can be reached under ideal circumstances. IFA’ 2004 4
WPAN n A wireless PAN consists of a dynamic group of less than 255 devices that communicate within about a 33 -foot range. n Unlike with wireless LANs, only devices within this limited area typically participate in the network, and no online connection with external devices is defined. n One device is selected to assume the role of the controller during wireless PAN initialization, and this controller device mediates communication within the WPAN. IFA’ 2004 5
WPAN n The controller broadcasts a beacon that lets all devices synchronize with each other and allocates time slots for the devices. n Each device attempts to join the wireless PAN by requesting a time slot from the controller. n The controller authenticates the devices and assigns time slots for each device to transmit data. n The data may be sent to the entire wireless PAN using the wireless PAN destination address, or it may be directed to a particular device. IFA’ 2004 6
WPAN n The 802. 15 working group is defining different versions for devices that have different requirements. n 802. 15. 3 focuses on high-bandwidth (about 55 M bit/sec), low-power MAC and physical layers, while 802. 15. 4 deals with lowbandwidth (about 250 K bit/sec), extra-low power MAC and physical layers. IFA’ 2004 7
WPAN: History n WPAN: smaller area of coverage, ad hoc only topology, plug and play architecture, support of voice and data devices, and low-power consumption. – Body. LAN (DARPA, mid-1990 s): inexpensive WPAN with modest bandwidth that could connect personal devices within a range of about 5 feet. – 802. 11 project initiated a WPAN group in 1997. In March 1998, the Home. RF group was formed In May 1998, a Bluetooth special group was formed In March 1999, 802. 15 was approved as a separate group to handle WPAN IFA’ 2004 8
IEEE 802. 15 WPAN n Development of standards for short distance wireless networks used for networking of portable ad mobile computing devices. n The original functional requirement was published in January 22, 1998, and specified devices with: – Power management: low current consumption – Range: 0 - 10 meters – Speed: 19. 2 - 100 kbps – Small size: . 5 cubic inches without antenna – Low cost relative to target device – Should allow overlap of multiple networks in the same area – Networking support for a minimum of 16 devices IFA’ 2004 9
IEEE 802. 15 WPAN n The initial activities in the WPAN group included Home. RF and Bluetooth group. n Home. RF currently has its own website [Home. RFweb] n IEEE 802. 15 WPAN has four task groups: – Task group 1: based on Bluetooth. Defines PHY and MAC for wireless connectivity with fixed, portable, and moving devices within or entering a personal operating space. – Task group 2: focused on coexistence of WPAN and 802. 11 WLANs. – Task group 3: PHY and MAC layers for high-rate WPANs (higher than 20 Mbps) – Task group 4: ultra-low complexity, ultra-low power consuming, ultra-low cost PHY and MAC layer for data rates of up to 200 kbps. IFA’ 2004 10
Bluetooth n Idea – Universal radio interface for ad-hoc wireless connectivity – Interconnecting computer and peripherals, handheld devices, PDAs, cell phones – replacement of Ir. DA – Embedded in other devices, goal: 5€/device (2002: 50€/USB Bluetooth) – Short range (10 m), low power consumption, licensefree 2. 45 GHz ISM – Voice and data transmission, approx. 1 Mbit/s gross data rate IFA’ 2004 11
Bluetooth One of the first modules (Ericsson). IFA’ 2004 12
History and hi-tech… IFA’ 2004 13
Bluetooth n History – 1994: Ericsson (Mattison/Haartsen), “MC-link” project – Renaming of the project: Bluetooth according to Harald “Blåtand” Gormsen [son of Gorm], King of Denmark in the 10 th century – 1998: foundation of Bluetooth SIG, www. bluetooth. org – 1999: erection of a rune stone at Ericsson/Lund – 2001: first consumer products for mass market, spec. version 1. 1 released n Special Interest Group – Original founding members: Ericsson, Intel, IBM, Nokia, Toshiba – Added promoters: 3 Com, Agere (was: Lucent), Microsoft, Motorola – > 2500 members – Common specification and certification of products IFA’ 2004 14
…and the real stone Located in Jelling, Denmark, erected by King Harald “Blåtand” in memory of his parents. The stone has three sides – one side showing a picture of Christ. Inscription: "Harald king executes these sepulchral monuments after Gorm, his father and Thyra, his mother. The Harald who won the whole of Denmark and Norway and turned the Danes to Christianity. " Btw: Blåtand means “of dark complexion” (not having a blue tooth…) IFA’ 2004 This could be the “original” colors of the stone. Inscription: “auk tani karthi kristna” (and made the Danes Christians) 15
Characteristics n 2. 4 GHz ISM band, 79 RF channels, 1 MHz carrier spacing – Channel 0: 2402 MHz … channel 78: 2480 MHz – G-FSK modulation, 1 -100 m. W transmit power n FHSS and TDD – Frequency hopping with 1600 hops/s – Hopping sequence in a pseudo random fashion, determined by a master – Time division duplex for send/receive separation n Voice link – SCO (Synchronous Connection Oriented) – FEC (forward error correction), no retransmission, 64 kbit/s duplex, point-to-point, circuit switched n Data link – ACL (Asynchronous Connection. Less) – Asynchronous, fast acknowledge, point-to-multipoint, up to 433. 9 kbit/s symmetric or 723. 2/57. 6 kbit/s asymmetric, packet switched n Topology – Overlapping piconets (stars) forming a scatternet IFA’ 2004 16
Bluetooth Protocol Stack audio apps. NW apps. v. Cal/v. Card TCP/UDP telephony apps. OBEX AT modem commands IP BNEP PPP mgmnt. apps. TCS BIN SDP Control RFCOMM (serial line interface) Audio Logical Link Control and Adaptation Protocol (L 2 CAP) Link Manager Host Controller Interface Baseband Radio AT: attention sequence OBEX: object exchange TCS BIN: telephony control protocol specification – binary BNEP: Bluetooth network encapsulation protocol IFA’ 2004 SDP: service discovery protocol RFCOMM: radio frequency comm. 17
Frequency Selection During Data Transmission (TDMA/TDD) 625 µs fk M symmetric fk+1 fk+2 fk+3 fk+4 fk+5 fk+6 S M S M t fk M asymmetric fk+3 S fk+4 fk+5 fk+6 M S M t fk asymmetric fk+1 M S fk+6 M t IFA’ 2004 18
Overall Frame Format of Bluetooth Packets n The 48 bit address unique to every Bluetooth device is used as the seed to derive the sequence for hopping frequencies of the devices. n Four types of access codes: – – – Type 1: identifies a “M” terminal and its piconet address Type 2: identifies a “S” identity used to page a specific “S”. Type 3: Fixed access code reserved for the inquiry process (will be explained) – Type 4: dedicated access code reserved to identify specific set of devices such as fax machines, printers, or cell phones. n Header: 18 bits repeated 3 times with a 1/3 FEC code 72 54 access code packet header 4 preamble 64 sync. IFA’ 2004 (4) (trailer) 3 S address 4 type 0 -2745 payload 1 flow bits 1 ARQN 1 SEQN 8 HEC 19
Overall Frame Format of Bluetooth Packets n S-address allows addressing the 7 possible “S” terminals in a piconet n The 4 -bit packet type allows for 16 choices of different grade voice systems: – 6 of this payload types are asynchronous connectionless (ACL), primarily used for packet data communication – 3 of the payload types are synchronous connection oriented (SCO), primarily used for voice communications – 1 a integrated voice (SCO) and data (ACL) packet – 4 are control packets common for both SCO and ACL links 72 54 access code packet header 4 preamble IFA’ 2004 64 sync. (4) (trailer) 3 S address 4 type 0 -2745 payload 1 flow bits 1 ARQN bits 1 SEQN 8 HEC 20
Control Packets n Four types: – ID: occupies half of a slot, and it carries the access code with no data or even a packet type code – NULL: used for ACK signaling, and there is no ACK for it – POLL: similar to the NULL, but is has an ACK l NULL and POLL: have the access code and the header, and so they have packet type codes and status report bits l “M” terminals use the POLL packet to find the “S” terminals in their coverage area. – FHS (Frequency Hop Synchronization): carries all the information necessary to synchronize two devices in terms of access code and hopping timing. This packet is used in the inquiry and paging process explained later. IFA’ 2004 21
Polling-based Transmission n Polling-based TDD packet transmission n n MASTER – 625µs slots, master polls slaves SCO (Synchronous Connection Oriented) – Voice – Periodic single slot packet assignment, 64 kbit/s full-duplex, point-to-point ACL (Asynchronous Connection. Less) – Data – Variable packet size (1, 3, 5 slots), asymmetric bandwidth, point-to-multipoint SCO f 0 SLAVE 1 SLAVE 2 IFA’ 2004 ACL f 4 SCO f 6 f 1 ACL f 8 f 7 f 5 SCO f 12 f 9 ACL f 14 SCO f 18 f 13 ACL f 20 f 19 f 17 f 21 22
Connection Management • In the beginning of the formation of a piconet, all devices are in SB mode, then one of the devices starts with an inquiry and becomes the “M” terminal. • During the inquiry process, “M” registers all the SB terminals that then become “S” terminals. After the inquiry process, identification and timing of all “S” terminals is sent to “M” using FHS packets. • The “M” terminal starts a connection with a PAGE message including its timing and ID to the “S” terminal. • When the connection is established, the communication takes place, and at the end, the terminal can be sent back to SB, Hold, park or Sniff states. Standby: do nothing Inquiry: search for other devices Page: connect to a specific device Connected: participate in a piconet IFA’ 2004 23
Connection Management • Hold, Park and Sniff are power-saving modes. • The Hold mode is used when connecting several piconets or managing a low-power device. • In the Hold mode, data transfer restarts as soon as the unit is out of this mode. • In the Sniff mode, a slave listens to the piconet at reduced and programmable intervals according to the applications needs. • In the Park mode a device gives up its MAC address but remains synchronized with the piconet. • A Parked device does not participate in the traffic but occasionally listens to the traffic of “M” to resynchronize and check on broadcast messages. IFA’ 2004 Park: release AMA, get PMA Sniff: listen periodically, not each slot Hold: stop ACL, SCO still possible, possibly participate in another piconet 24
Interference Between Bluetooth and 802. 11 n The WLAN industry specified three levels of overlapping: – Interference: multiple wireless networks are said to interfere with one another if colocation causes significant performance degradation – Coexistence: multiple wireless networks are said to coexist if they can be colocated without significant impact on performance. It provides for the ability of one system to perform a task in a shared frequency band with other systems that may or may not be using the same rules for operation – Interoperation: provides for an environment with multiple wireless systems to perform a given task using a single set of rules IFA’ 2004 25
Piconet n Collection of devices connected in an ad hoc fashion n One unit acts as master and the others as slaves for the lifetime of the piconet n Master determines hopping pattern, slaves have to synchronize n Each piconet has a unique hopping pattern P S S M P SB S P SB n Participation in a piconet = synchronization to hopping sequence n Each piconet has one master and up to 7 simultaneous slaves (> 200 could be parked) IFA’ 2004 M=Master S=Slave P=Parked SB=Standby 26
Forming a Piconet n All devices in a piconet hop together – Master gives slaves its clock and device ID l Hopping pattern: determined by device ID (48 bit, unique worldwide) l Phase in hopping pattern determined by clock n Addressing – Active Member Address (AMA, 3 bit) – Parked Member Address (PMA, 8 bit) SB SB SB SB SB SB IFA’ 2004 S SB P S M P S P SB 27
Scatternet n Linking of multiple co-located piconets through the sharing of common master or slave devices – Devices can be slave in one piconet and master of another n Communication between piconets – Devices jumping back and forth between the piconets P S Piconets (each with a capacity of < 1 Mbit/s) S S M=Master S=Slave P=Parked SB=Standby IFA’ 2004 P P M M SB S P SB SB S 28
WPAN: IEEE 802. 15 -1 – Bluetooth n Data rate – Synchronous, connection-oriented: 64 kbit/s – Asynchronous, connectionless l 433. 9 kbit/s symmetric kbit/s l 723. 2 / 57. 6 kbit/s asymmetric kbit/s n Transmission range – POS (Personal Operating Space) up to 10 m – with special transceivers up to 100 m n Frequency – Free 2. 4 GHz ISM-band n Security – Challenge/response (SAFER+), hopping sequence n Cost – 50€ adapter, drop to 5€ if integrated n Availability – Integrated into some products, several vendors IFA’ 2004 n Connection set-up time – Depends on power-mode – Max. 2. 56 s, avg. 0. 64 s n Quality of Service – Guarantees, ARQ/FEC n Manageability – Public/private keys needed, key management not specified, simple system integration n Special Advantages/Disadvantages – Advantage: already integrated into several products, available worldwide, free ISM-band, several vendors, simple system, simple ad-hoc networking, peer to peer, scatternets – Disadvantage: interference on ISM-band, limited range, max. 8 devices/network&master, high set -up latency 29
WPAN: IEEE 802. 15 – future developments 1 n 802. 15 -2: Coexistence – Coexistence of Wireless Personal Area Networks (802. 15) and Wireless Local Area Networks (802. 11), quantify the mutual interference n 802. 15 -3: High-Rate – Standard for high-rate (20 Mbit/s or greater) WPANs, while still low-power/low-cost – Data Rates: 11, 22, 33, 44, 55 Mbit/s – Quality of Service isochronous protocol – Ad hoc peer-to-peer networking – Security – Low power consumption – Low cost – Designed to meet the demanding requirements of portable consumer imaging and multimedia applications IFA’ 2004 30
WPAN: IEEE 802. 15 – future developments 2 n 802. 15 -4: Low-Rate, Very Low-Power – Low data rate solution with multi-month to multi-year battery life and very low complexity – Potential applications are sensors, interactive toys, smart badges, remot controls, and home automation – Data rates of 20 -250 kbit/s, latency down to 15 ms – Master-Slave or Peer-to-Peer operation – Support for critical latency devices, such as joysticks – CSMA/CA channel access (data centric), slotted (beacon) or unslotted – Automatic network establishment by the PAN coordinator – Dynamic device addressing, flexible addressing format – Fully handshaked protocol for transfer reliability – Power management to ensure low power consumption – 16 channels in the 2. 4 GHz ISM band, 10 channels in the 915 MHz US ISM band one channel in the European 868 MHz band IFA’ 2004 31
Bluetooth n n Why not use Wireless LANs? - power - cost A cable replacement technology 1 Mb/s symbol rate Range 10+ meters Single chip radio + baseband – at low power & low price point ($5) IFA’ 2004 32
IEEE 802. 11: Classical WLANs n Replacement for Ethernet n Supported data rates – 11, 5. 5, 2, 1 Mbps; and recently up to 20+Mbps @ 2. 4 GHz – up to 54 Mbps in 5. 7 GHz band (802. 11 a) n Range – Indoor 20 - 25 meters – Outdoor: 50 – 100 meters n Transmit power up to 100 m. W n Cost: – Chipsets $ 35 – 50 – AP $200 - $1000 IFA’ 2004 33 – PCMCIA cards $100 - $150
IEEE 802. 11 Emerging Landscape New developments are blurring the distinction Bluetooth Cordless headset < 802. 11 b for PDAs LAN AP < Bluetooth for LAN access n Which option is technically superior ? n What market forces are at play ? n What can be said about the future ? IFA’ 2004 34
Bluetooth Working Group History n February 1998: The Bluetooth SIG is formed – promoter company group: Ericsson, IBM, Intel, Nokia, Toshiba n May 1998: Public announcement of the Bluetooth SIG n July 1999: 1. 0 A spec (>1, 500 pages) is published n December 1999: ver. 1. 0 B is released n December 1999: The promoter group increases to 9 – 3 Com, Lucent, Microsoft, Motorola n March 2001: ver. 1. 1 is released n Aug 2001: There are 2, 491+ adopter companies IFA’ 2004 35
New Applications IFA’ 2004 36
Synchronization User benefits n Automatic synchronization of calendars, address books, business cards n Push button synchronization n Proximity operation IFA’ 2004 37
Cordless Headset Cordless headset User benefits n Multiple device access n Cordless phone benefits n Hands free operation IFA’ 2004 38
Usage Scenarios Examples n Data Access Points n Synchronization n Headset n Conference Table n Cordless Computer n Business Card Exchange n Instant Postcard n Computer Speakerphone IFA’ 2004 39
Bluetooth Specifications IFA’ 2004 40
Bluetooth Specifications Applications IP RFCOMM Data Audio HC I SDP L 2 CAP Link Manager Baseband RF Single chip with RS-232, USB, or PC card interface n A hardware/software/protocol description n An application framework IFA’ 2004 41
Interoperability & Profiles IFA’ 2004 Applications Protocols n Represents default solution for a usage model n Vertical slice through the protocol stack n Basis for interoperability and logo requirements n Each Bluetooth device supports one or more profiles Profiles 42
Bluetooth Profiles (in version 1. 2 release) n n n n Generic Access Service Discovery Cordless Telephone Intercom Serial Port Headset Dial-up Networking Fax LAN Access Generic Object Exchange Object Push File Transfer Synchronization IFA’ 2004 43
Technical Overview IFA’ 2004 44
Bluetooth Radio Specification Applications IP Data Audio rol RFCOMM Co nt SDP L 2 CAP Link Manager Baseband RF IFA’ 2004 45
Unlicensed Radio Spectrum 33 cm 26 Mhz 902 Mhz 12 cm 83. 5 Mhz 2. 4 Ghz 928 Mhz cordless phones baby monitors Wireless LANs IFA’ 2004 2. 4835 Ghz 802. 11 Bluetooth Microwave oven 5 cm 125 Mhz 5. 725 Ghz 5. 785 Ghz 802. 11 a Hyper. Lan 48
Bluetooth Radio Link 1 Mhz . . . 79 12 3 83. 5 Mhz n frequency hopping spread spectrum – 2. 402 GHz + k MHz, k=0, …, 78 – 1, 600 hops per second n GFSK modulation – 1 Mb/s symbol rate n transmit power – 0 dbm (up to 20 dbm with power control) IFA’ 2004 49
Review of Basic Concepts IFA’ 2004 50
Baseband SDP IP RFCOMM L 2 CAP rol Audio RFCOMM Co nt SDP Co ntr Applications Data IP ol Applications Link Manager Data Baseband L 2 CAP RF Audio Link Manager Baseband RF IFA’ 2004 51
Bluetooth Physical Link n. Point to point link – master - slave relationship – radios can function as masters or slaves n. Piconet – Master can connect to 7 slaves – Each piconet has max capacity =1 Mbps – hopping pattern is IFA’ 2004 determined by the master m s s s 52
Connection Setup n Inquiry - scan protocol – to learn about the clock offset and device address of other nodes in proximity IFA’ 2004 53
Inquiry on Time Axis Slave 1 f 2 Inquiry hopping sequence Master Slave 2 IFA’ 2004 54
Piconet Formation n Page - scan protocol – to establish links with nodes in proximity Master Active Slave Parked Slave Standby IFA’ 2004 55
Addressing n Bluetooth device address (BD_ADDR) – 48 bit IEEE MAC address n Active Member address (AM_ADDR) – 3 bits active slave address – all zero broadcast address n Parked Member address (PM_ADDR) – 8 bit parked slave address IFA’ 2004 56
Piconet Channel FH/TDD f 1 f 2 f 3 f 4 f 5 f 6 m s 1 s 2 625 sec IFA’ 2004 1600 hops/sec 57
Multi Slot Packets FH/TDD f 1 f 4 f 5 f 6 m s 1 s 2 625 µsec IFA’ 2004 Data rate depends on type of packet 58
Physical Link Types < Synchronous Connection Oriented (SCO) Link 4 slot reservation at fixed intervals n Asynchronous Connection-less (ACL) Link – Polling access method m SCO ACL ACL SCO ACL s 1 s 2 IFA’ 2004 59
Packet Types Data/voice packets Control packets ID* Null Poll FHS DM 1 IFA’ 2004 Voice HV 1 HV 2 HV 3 DV data DM 1 DM 3 DM 5 DH 1 DH 3 DH 5 60
Packet Format 72 bits 54 bits Access code Header Voice No CRC No retries FEC (optional) 0 - 2744 bits Payload header Data CRC ARQ FEC (optional) 625 µs master slave IFA’ 2004 61
Access Code 72 bits Access code Header Purpose n Synchronization n DC offset compensation n Identification n Signaling Payload Types < Channel Access Code (CAC) < Device Access Code (DAC) < Inquiry Access Code (IAC) X IFA’ 2004 62
Packet Header 54 bits Access code Header s Purpose n n n Addressing Packet type Flow control 1 -bit ARQ Sequencing HEC total m Payload (3) (4) (1) (1) (8) s s Max 7 active slaves 16 packet types (some unused) Broadcast packets are not ACKed For filtering retransmitted packets Verify header integrity 18 bits Encode with 1/3 FEC to get 54 bits IFA’ 2004 63
Data Packet Types DM 1 DM 3 2/3 FEC No FEC DM 5 DH 1 DH 3 DH 5 IFA’ 2004 65
Inter Piconet Communication Cordless headset mouse Cordless headset Cell phone IFA’ 2004 Cordless headset 66
Scatternet IFA’ 2004 67
Scatternet, Scenario 2 How to schedule presence in two piconets? Forwarding delay ? Missed traffic? IFA’ 2004 68
Baseband: Summary Device 1 L 2 CAP LMP Device 2 L 2 CAP Data link LMP Baseband Physical n TDD, frequency hopping physical layer n Device inquiry and paging n Two types of links: SCO and ACL links n Multiple packet types (multiple data rates with and without FEC) IFA’ 2004 69
Link Manager Protocol Applications IP SDP Audio Co ntr Data ol RFCOMM Setup and management of Baseband connections L 2 CAP Link Manager Baseband RF IFA’ 2004 LMP • Piconet Management • Link Configuration • Security 70
Piconet Management Attach and detach slaves Master-slave switch Establishing SCO links Handling of low power modes ( Sniff, Hold, Park) n n Paging IFA’ 2004 s s req response Slave s Master m 71
Low Power Mode (hold) Hold offset Slave Hold duration Master IFA’ 2004 72
Low Power Mode (Sniff) Sniff offset Sniff duration Slave Sniff period Master n Traffic reduced to periodic sniff slots IFA’ 2004 73
Low Power Mode (Park) Slave Beacon instant Master Beacon interval n Power saving + keep more than 7 slaves in a piconet n Give up active member address, yet maintain synchronization n Communication via broadcast LMP messages IFA’ 2004 74
Connection Establishment & Security n Goals – Authenticated access l Only accept connections from trusted devices – Privacy of communication l prevent eavesdropping 4 Cannot rely on PKI 4 Simple user experience IFA’ 2004 Security procedure LMP_setup_complete Slave = $10 headsets, joysticks LMP_host_conn_req LMP Accepted Master < Constraints 4 Processing and memory limitations Paging LMP_setup_complete 75
Authentication n Authentication is based on link key (128 bit shared secret between two devices) n How can link keys be distributed securely ? Link key IFA’ 2004 response accepted Claimant Verifier challenge Link key 76
Pairing (Key Distribution) n Pairing is a process of establishing a trusted secret channel between two devices (construction of initialization key Kinit) n Kinit is then used to distribute unit keys or combination keys PIN + Verifier Claimant address Random number Claimant challenge Kinit IFA’ 2004 + Claimant address Random number response accepted PIN Kinit 77
Link Manager Protocol Summary Device 1 L 2 CAP LMP Device 2 L 2 CAP Data link LMP Baseband Physical n Piconet management n Link configuration – Low power modes – Qo. S – Packet type selection n Security: authentication and encryption IFA’ 2004 78
L 2 CAP Applications IP SDP Logical Link Control and Adaptation Protocol RFCOMM Data Audio L 2 CAP Link Manager Baseband RF IFA’ 2004 L 2 CAP provides • Protocol multiplexing • Segmentation and Re-assembly • Quality of service negotiation 79
L 2 CAP Applications IP SDP Logical Link Control and Adaptation Protocol RFCOMM Data Audio L 2 CAP Link Manager Baseband RF IFA’ 2004 L 2 CAP provides • Protocol multiplexing • Segmentation and Re-assembly • Quality of service negotiation 80
Why baseband isn’t sufficient? IP MTU Baseband RFCOMM IP RFCOMM Multiplexing demultiplexing reliable*, flow controlled in-sequence, asynchronous link • Baseband packet size is very small (17 min, 339 max) • No protocol-id field in the baseband header IFA’ 2004 81
Need a Multiprotocol Encapsulation Layer IP IP RFCOMM unreliable, no integrity reliable*, in-order, flow controlled, ACL link Desired features • Protocol multiplexing • Segmentation and re-assembly • Quality of service IFA’ 2004 What about • Reliability? • Connection oriented or connectionless? • integrity checks? 82
Segmentation and Reassembly Payload Length Baseband packets start of L 2 CAP CRC continuation of L 2 CAP • cannot cope with re-ordering or loss • mixing of multiple L 2 CAP fragments not allowed • If the start of L 2 CAP packet is not acked, the rest should be discarded IFA’ 2004 min MTU = 48 672 default 83
Serial Port Emulation using RFCOMM Applications IP SDP RFCOMM Data Audio L 2 CAP Link Manager Baseband RF IFA’ 2004 Serial Port emulation on top of a packet oriented link • Similar to HDLC • For supporting legacy apps 91
Serial Line Emulation over Packet based MAC RFCOMM L 2 CAP n Design considerations – framing: assemble bit stream into bytes and, subsequently, into packets – transport: in-sequence, reliable delivery of serial stream – control signals: RTS, CTS, DTR IFA’ 2004 92
IP over Bluetooth V 1. 0 Applications IP SDP RFCOMM Data Audio L 2 CAP Link Manager Baseband RF IFA’ 2004 GOALS n Internet access using cell phones n Connect PDA devices & laptop computers to the Internet via LAN access points 93
LAN Access Point Profile IP Access Point PPP Why use PPP? Security Authentication Access control Efficiency header and data compression Auto-configuration Lower barrier for deployment IFA’ 2004 RFCOMM L 2 CAP Baseband 94
Inefficiency of Layering Palmtop IP PPP rfc 1662 LAN access point packet oriented byte oriented PPP rfc 1662 RFCOMM L 2 CAP IP packet oriented L 2 CAP n Emulation of RS-232 over the Bluetooth radio link could be eliminated IFA’ 2004 95
Terminate PPP at LAN Access Point Palmtop Access Point IP IP PPP RFCOMM Bluetooth ethernet Bluetooth n PPP server function at each access point – management of user name/password is an issue – roaming is not seamless IFA’ 2004 96
L 2 TP Tunneling Palmtop Access Point PPP server IP IP PPP UDP RFCOMM IP IP Bluetooth ethernet n Tunneling PPP traffic from access points to the PPP server – 1) centralized management of user name/password – 2) reduction of processing and state maintenance at each access point – 3) seamless roaming IFA’ 2004 97
Seamless Roaming with PPP Server 1 REQ 2 RPL 5 CLR AP 1 MAC level registration PPP palmtop IFA’ 2004 4 RPL 3 REQ AP 2 MAC level handoff PPP 98
Bluetooth Current Market Outlook IFA’ 2004 100
Market Forecasts for Year 2005 Cahners In-stat (2000 forcast) revised (2001 forcast) Merrill Lynch (2000 forcast) $ 5. 4 bn 2. 1 bn $ 4. 4 bn $ 4. 3 bn 1. 4 bn revised (2001 forcast) $ 2. 2 bn $ 4. 4 1. 5 bn 995 m $ 3. 6 $ 2. 02 Units sold annually IFA’ 2004 Revenue Chip price 101
Value to Carriers: Synchronization and Push n More bits over the air n Utilization of unused capacity during nonbusy periods n Higher barrier for switching service providers IFA’ 2004 103
Value to Carriers: Cell phone as an IP Gateway Will Pilot and cell phone eventually merge? n More bits over the air n Enhanced user experience – Palmpilot has a better UI than a cell phone n Growth into other vertical markets IFA’ 2004 104
Value to Carriers: Call Handoff Cordless base Threat or opportunity? n More attractive calling plans n Alleviate system load during peak periods n Serve more users with fewer resources IFA’ 2004 105
Biggest Challenges facing Bluetooth n Interoperability – Always a challenge for any new technology n Hyped up expectations n Out of the box ease of use n Cost target $5 n Critical mass n RF in silicon n Conflicting interests – business and engineering IFA’ 2004 106
![References n [1] IEEE 802. 11, “Wireless LAN MAC and Physical Layer Specification, ”](https://present5.com/presentation/2a409be763bcfbac60a53e0f8cf4f74f/image-95.jpg "References n [1] IEEE 802. 11, “Wireless LAN MAC and Physical Layer Specification, ”")
References n [1] IEEE 802. 11, “Wireless LAN MAC and Physical Layer Specification, ” June 1997. n [2] Hirt, W. ; Hassner, M. ; Heise, N. “Ir. DA–VFIr (16 Mb/s): modulation code and system design. ” IEEE Personal Communications, vol. 8, (no. 1), IEEE, Feb. 2001. n [3] Lansford, J. ; Bahl, P. “The design and implementation of Home. RF: a radio frequency wireless networking standard for the connected home. ” Proceedings of the IEEE, Oct. 2000. n [4] Specification of Bluetooth System, ver. 1. 0, July 1999 IFA’ 2004 107
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References (cnt) n [5] Haartsen, J. C. “The Bluetooth radio system. ”, IEEE Personal Communications, IEEE, Feb. 2000. n [6] Haartsen, J. C. ‘Bluetooth towards ubiquitous wireless connectivity. ’, Revue HF, Soc. Belge Ing. Telecommun. & Electron, 2000. p. 8– 16. n [7] Rathi, S. “Bluetooth protocol architecture. ” Dedicated Systems Magazine, Dedicated Systems Experts, Oct. –Dec. 2000. n [8] Haartsen, J. C. ; Mattisson, S. “Bluetooth–a new low–power radio interface providing short–range connectivity. ” Proceedings of the IEEE, Oct. 2000. n [9] Gilb, J. P. K “Bluetooth radio architectures. ” 2000 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium Digest of Papers, Boston, MA, USA, 11– 13 June 2000. IFA’ 2004 108
![References (cnt) n [10] N. Benvenuto, G. Cherubini, “Algoritmi e circuiti per le telecomunicazioni”,](https://present5.com/presentation/2a409be763bcfbac60a53e0f8cf4f74f/image-97.jpg "References (cnt) n [10] N. Benvenuto, G. Cherubini, “Algoritmi e circuiti per le telecomunicazioni”,")
References (cnt) n [10] N. Benvenuto, G. Cherubini, “Algoritmi e circuiti per le telecomunicazioni”, Ed. Libreria Progetto. n [11] The Bluetooth Special Interest Group, Documentation available at http: //www. bluetooth. com/ n [12] IEEE 802. 15 Working Group for WPANs™; http: //www. manta. ieee. org/groups/802/15/ n [13] Barker, P. ; Boucouvalas, A. C. ; Vitsas, V. “Performance modelling of the Ir. DA infrared wireless communications protocol. ” International Journal of Communication Systems, vol. 13, Wiley, Nov. –Dec. 2000. n [14] Tokarz, K. ; Zielinski, B. “Performance evaluation of Ir. DA wireless transmission. ” 7 th Conference on Computer Networks, Zakopane, Poland, 14– 16 June 2000. n [15] ETSI RES, “Digital European Cordless Telecommunications (DECT), Common interface Part 1: Overview, ” ETS 300 175– 1, 1996. IFA’ 2004 109
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