Week 6 lecture 1+2 n Bluetooth

2 of 27 Finish Data Link layer Finish Data Link layer - CRC - CRC - CSMA - CSMA - Hints for Lab 4 - Hints for Lab 4

3 of 27 WPAN: INTRODUCTION A WPAN (Wireless PAN) is a short-distance wireless network specifically designed to support portable and mobile computing devices such as PCs, PDAs, wireless printers and storage devices, cell phones, pagers, set- top boxes, and a variety of consumer electronics equipment. A WPAN (Wireless PAN) is a short-distance wireless network specifically designed to support portable and mobile computing devices such as PCs, PDAs, wireless printers and storage devices, cell phones, pagers, set- top boxes, and a variety of consumer electronics equipment. 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. 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. Many cell phones have two radio interfaces-one for the cellular network and one for PAN connections. Many cell phones have two radio interfaces-one for the cellular network and one for PAN connections.

4 of 27 IEEE WPAN Development of standards for short distance wireless networks used for networking of portable ad mobile computing devices. Development of standards for short distance wireless networks used for networking of portable ad mobile computing devices. The original functional requirement was published in January 22, 1998, and specified devices with: The original functional requirement was published in January 22, 1998, and specified devices with: –Power management: low current consumption –Range: meters –Speed: kbps –Small size: 0.5 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

5 of 27 IEEE WPAN The initial activities in the WPAN group included HomeRF and Bluetooth group. The initial activities in the WPAN group included HomeRF and Bluetooth group. HomeRF currently has its own website [HomeRFweb] HomeRF currently has its own website [HomeRFweb] IEEE WPAN has 4 task groups: IEEE WPAN has 4 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 WLANs. –Task group 3: PHY and MAC layers for high-rate WPANs (higher than 20 Mbps) -- Not bluetooth! –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 (such as WSN).

6 of 27 WPAN: IEEE – Bluetooth Data rate Data rate –Synchronous, connection-oriented: 64 kbit/s –Asynchronous, connectionless kbit/s symmetric kbit/s symmetric / 57.6 kbit/s asymmetric / 57.6 kbit/s asymmetric Transmission range Transmission range –POS (Personal Operating Space) up to 10 m –with special transceivers up to 100 m Frequency Frequency –Free 2.4 GHz ISM-band Security Security –Challenge/response (SAFER+), hopping sequence Cost Cost –50€ adapter, drop to 5€ if integrated Availability Availability –Integrated into some products, several vendors Connection set-up time Connection set-up time –Depends on power-mode –Max. 2.56s, avg. 0.64s Quality of Service Quality of Service –Guarantees, ARQ/FEC Manageability Manageability –Public/private keys needed, key management not specified, simple system integration Special Advantages/Disadvantages 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

7 of 27 WPAN: IEEE & : Coexistence : Coexistence –Coexistence of Wireless Personal Area Networks (802.15) and Wireless Local Area Networks (802.11), quantify the mutual interference : High-Rate : High-Rate –Standard for high-rate (20Mbit/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

8 of 27 WPAN: IEEE : Low-Rate, Very Low-Power : 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, remote controls, and home automation –Data rates of 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 and one channel in the European 868 MHz band

9 of 27Bluetooth A cable replacement technology A cable replacement technology 1 Mb/s symbol rate 1 Mb/s symbol rate Range 10+ meters Range 10+ meters Single chip radio + baseband Single chip radio + baseband –at low power & low price point ($5) Why not use Wireless LANs? - power - cost

10 of 27 Bluetooth Idea Idea –Universal radio interface for ad-hoc wireless connectivity –Interconnecting computer and peripherals, handheld devices, PDAs, cell phones – replacement of IrDA –Embedded in other devices, goal: 5€/device (2002: 50€/USB Bluetooth) –Short range (10 m), low power consumption, license-free 2.45 GHz ISM –Voice and data transmission, approx. 1 Mbit/s gross data rate

11 of 27 Bluetooth One of the first modules (Ericsson).

12 of 27 Usage Scenarios Examples Data Access Points Data Access Points Synchronization Synchronization Headset Headset Conference Table Conference Table Cordless Computer Cordless Computer Business Card Exchange Business Card Exchange Instant Postcard Instant Postcard Computer Speakerphone Computer Speakerphone

13 of 27 History and hi-tech…

14 of 27 Bluetooth History 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, –1999: erection of a rune stone at Ericsson/Lund –2001: first consumer products for mass market, spec. version 1.1 released Special Interest Group Special Interest Group –Original founding members: Ericsson, Intel, IBM, Nokia, Toshiba –Added promoters: 3Com, Agere (was: Lucent), Microsoft, Motorola –> 2500 members –Common specification and certification of products

15 of 27 …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. This could be the “original” colors of the stone. Inscription: “auk tani karthi kristna” (and made the Danes Christians) 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…)

16 of 27 Characteristics 2.4 GHz ISM band, 79 RF channels, 1 MHz carrier spacing 2.4 GHz ISM band, 79 RF channels, 1 MHz carrier spacing –Channel 0: 2402 MHz … channel 78: 2480 MHz –G-FSK modulation, mW transmit power FHSS and TDD 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 Voice link – SCO (Synchronous Connection Oriented) Voice link – SCO (Synchronous Connection Oriented) –FEC (forward error correction), no retransmission, 64 kbit/s duplex, point-to-point, circuit switched Data link – ACL (Asynchronous ConnectionLess) Data link – ACL (Asynchronous ConnectionLess) –Asynchronous, fast acknowledge, point-to-multipoint, up to kbit/s symmetric or 723.2/57.6 kbit/s asymmetric, packet switched Topology Topology –Overlapping piconets (stars) forming a scatternet

17 of 27 Bluetooth Protocol Stack Radio Baseband Link Manager Control Host Controller Interface Logical Link Control and Adaptation Protocol (L2CAP) Audio TCS BINSDP OBEX vCal/vCard IP NW apps. TCP/UDP BNEP RFCOMM (serial line interface) AT modem commands telephony apps.audio apps.mgmnt. apps. AT: attention sequence OBEX: object exchange TCS BIN: telephony control protocol specification – binary BNEP: Bluetooth network encapsulation protocol SDP: service discovery protocol RFCOMM: radio frequency comm. PPP

18 of 27 Connection Management Standby: do nothing Inquiry: search for other devices Page: connect to a specific device Connected: participate in a piconet 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.

19 of 27 Connection Management Park: release AMA, get PMA Sniff: listen periodically, not each slot Hold: stop ACL, SCO still possible, possibly participate in another piconet 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.

20 of 27 Interference Between Bluetooth and The WLAN industry specified three levels of overlapping: The WLAN industry specified three levels of overlapping: –Interference: multiple wireless networks are said to interfere with one another if co-location causes significant performance degradation –Coexistence: multiple wireless networks are said to coexist if they can be co-located 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 –Inter-operation: provides for an environment with multiple wireless systems to perform a given task using a single set of rules

21 of 27 Piconet Collection of devices connected in an ad hoc fashion One unit acts as master and the others as slaves for the lifetime of the piconet Master determines hopping pattern, slaves have to synchronize Each piconet has a unique hopping pattern Participation in a piconet = synchronization to hopping sequence Each piconet has one master and up to 7 simultaneous slaves (> 200 could be parked) M=Master S=Slave P=Parked SB=Standby M S P SB S S P P

22 of 27 Forming a Piconet All devices in a piconet hop together All devices in a piconet hop together –Master gives slaves its clock and device ID Hopping pattern: determined by device ID (48 bit, unique worldwide) Hopping pattern: determined by device ID (48 bit, unique worldwide) Phase in hopping pattern determined by clock Phase in hopping pattern determined by clock Addressing Addressing –Active Member Address (AMA, 3 bit) –Parked Member Address (PMA, 8 bit) SB M S P S S P P                  

23 of 27 Scatternet Linking of multiple co-located piconets through the sharing of common master or slave devices 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 Communication between piconets Communication between piconets –Devices jumping back and forth between the piconets M=Master S=Slave P=Parked SB=Standby M S P SB S S P P M S S P Piconets (each with a capacity of < 1 Mbit/s)