Ericsson
`
`VIE
`
`TH E TE LE on MMU-N-I CA-"Tl 0'-N s ‘_FEcH'N_0L’0G-Y J0 u R§N'.{l'L
`
`Bluetooth—The unlversal radlo interface for ad hoc, wireless connectivity
`
`Internet directory services with click-to-dial
`
`Jambala—|ntelligence beyond digital wireless
`
`ERl0N—Erlcsson optical networking using WDM technology
`
`Access 910 system
`
`ERICSSON 3
`
`Samsung Ex. 1407A p. 1
`
`Samsung Ex. 1407A p. 1
`
`

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`-_-—---.—-—_—....—._¢_._.._.r_»-._—;..............-—--.
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`
` R't3”i"/IEW
`
`The telecommunications
`technology Journal
`
`The purpose of Ericsson Review is to
`report on the research, development
`and production achievements made in
`telecommunications technology at
`Ericsson. The journal is published in
`English and Spanish and distributed
`quarterly to readers in more than 130
`countries.
`
`Address:
`
`Telefonaktiebolaget LM Ericsson
`S-126 25 Stockholm, Sweden
`
`Tel: +46 8 719 00 00
`
`Fax: +46 8 681 27 10
`
`Internet address:
`
`Contents
`
`
`Bluetooth—The universal radio interface for ad hoc,
`
`http://www.ericsson.com/Review
`
`wireless connectivity
`
`Publisher: Lars A. Srélberg
`
`Editorial board: Hans Alberg, Gteger
`Berg, Tom Boothe, Mikael Biick,
`Philippe Charas, Jonas Hermansson,
`Anders Hidmark, Lena Krogstad, Filip
`Lindell, Bo Malmberg, Mats Nilsson,
`Eric Peterson, G61-an Rassmuson,
`Michele Schmidt, Ole Segtnan, Sture
`Sjfistriim, Bengt Stavenow. Lars-
`Gunnar Sundin, Peter Sviird
`
`Editor: Eric Peterson
`
`Production manager: Eva Karlstein
`
`Layout: Paues Media, Stockholm
`
`Printer: Ljungfdretagen, Orebro
`
`ISSN: 0014-0171
`
`Volume: 75, 1998
`
`cover: Bluetooth technology substitutes a
`universal short—range radio link for the
`many proprietary cables that are presently
`used for connecting devices. But more than
`this, Bluetooth radio technology provides a
`universal bridge to existing data networks,
`a peripheral interface, and a mechanism for
`forming small ad but groupings of connect-
`ed devices away from fixed network infra-
`structures.
`
`© Telefonaktiebolaget LM Ericsson
`
`Ericsson Review No. 3, 1998
`
`Imagine a cheap, power-efficient radio chip that is small enough to fit inside
`any electronic device or machine and that provides local connectivity. Bluetooth
`is a universal radio interface in the 2.45 GHz frequency band that enables
`portable electronic devices to connect and communicate wirelessly via at! am-
`networks.
`Page 110
`
`Internet directory services with click-to-dial
`Internet directory services make available vast resources of the Internet, helping
`users to save valuable time in finding names, e-mail addresses, and so forth. Click-
`to-dial services allow users to invoke calls by clicking on the phone number they
`retrieve using directory services. Ericsson's solution sets up and transmits calls via
`the PSTN, but it is equally compatible with VoIP.
`Page 118
`
`Jambala—|ntelIlgence beyond digital wireless
`Jambala is the next—generation application platform that operators need to provide
`new, high-value services in an increasingly segmented entl-user market. jambala
`provides a unique combination of availability, reliability, scalability and lnternet
`rt-acliness-—all using com rncrcially available hardware.
`Page 126
`
`ERlON—Ericsson optical networking using WDM
`
`-V"
`technology
`Ericsson maintains a simple, pragmatic approach to networking as they further ex-
`plore and exploit dense WDM technology and optical networking. Ericsson's next-
`generation transport-network technology—ERION—enables operators to derive
`maximum benefit from investments in client technology, while simplifying net-
`
`works and improving traffic protection and routing functionality.
`
`Page 132
`
`Access 910 system
`Ericsson's Access 910 is a general-purpose, access-network system that provides
`PSTN, Internet, VoIP, ATM, and switched video broadcast capabilities to a wide
`range ofse1’vice networks. The support it provides for practical, cost-effective mi-
`gration from narrowbanrl to broadband services nmltes it ideal for present-day and
`future telecom environments.
`Page 138
`
`107
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` amsung x.
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`p.
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`Samsung Ex. 1407A p. 2
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`

`
`Bluetooth—The universal radio interface for
`ad hoc, wireless connectivity
`
`Jaap Haartsen
`
`I I I IIIII I III IIIIIII I II IIII III II II III IIIIIIIIIIIIIII
`
`was to eliminate cables between phones and
`PC cards, wireless headsets, and so forth.
`The study was part of a larger project that
`investigated multi-communicators
`con-
`nected to the cellular network via cellular
`telephones. The last link in the connection
`between a communicator and the cellular
`network was a short-range radio link to the
`phone——thus, the link was called the multi-
`communicator link or MC link. As the MC
`link project progressed, it became clear that
`there was no limit to the kinds of applica-
`tion that could use a short-range radio link.
`Cheap, short-range radios would make wire-
`less communication between portable de-
`vices economically feasible.
`Current portable devices use infrared
`links (IrDA) to communicate with each
`other. Although infrared transceivers are in-
`expensive, they
`I have limited range (typically one to two
`meters);
`I are sensitive to direction and require
`direct line-of-sight;
`3 can in principle only be used between two
`devices.
`
`By contrast, radios have much greater range,
`can propagate around objects and through
`various materials, and connect to many de-
`vices simultaneously. What is more, radio
`interfaces do not require user interaction.
`In the beginning of 1997, when design-
`ers had already begun work on an MC link
`
`I ll." ,
`
`A , -,1’, — ’
`
`lg
`u—. in
`
`Bluetooth is a universal radio Interface in the 2.45 GHz frequency band that
`enables portable electronic devices to connect and communicate wlrelessly
`via short-range, ad hoc networks. Each unit can simultaneously communi-
`cate with up to seven other units per piconet. Moreover, each unit can
`simultaneously belong to several piconets.
`Bluetooth technology—whlch apart from Ericsson, has gained the support
`of Nokia, IBM, Toshiba, Intel and many other manufacturers—eIimInates the
`need for wires, cables and connectors for and between cordless or mobile
`phones, modems, headsets, PDAs, computers, printers, projectors, local
`area networks, and so on, and paves the way for new and completely differ-
`ent devices and applications.
`Before guiding us through frequency-hopping technology and the channel,
`packet and physical-link definitions that characterize the Bluetooth air Inter-
`face, the author briefiy describes the conditions that led up to the develop-
`ment of Bluetooth. He then acquaints us with the networking aspects of
`Bluetooth technology, describing piconets and scatternets, connection pro-
`cedures, and inter-plconet communication.
`
`Imagine a cheap, power-efficient radio chip
`that is small enough to fit inside any elec-
`tronic device or machine, that provides local
`connectivity, and that creates a (worldwide)
`micro-scale web. What applications might
`you use it in?
`In 1994, Ericsson Mobile Communica-
`tions AB in Lund, Sweden, initiated a study
`to investigate the feasibility ofa low-power,
`low-cost radio interface between mobile
`
`phones and their accessories. The intention
`
`LAN
`
`Access point
`
`Headset \
`
`Mouse
`
`Figure 1
`User model with local wireless connectivity. 1» '
`Applications envisioned for the near future.
`Monet
`
`110
`
` j
`
`Cellular network
`
`Mobile phone
`
`Erlcsson Review No. 3. 1998
`
`!amsung
`
`1407! p. 3
`
`Samsung Ex. 1407A p. 3
`
`

`
`,
`
`T-
`
`:
`
`l
`
`transceiver chip, Ericsson approached other
`manufacturers ofportable devices to raise in—
`terest in the technology—for the system to
`succeed, a critical mass of portable devices
`must use the short-range radio. In February
`1998.
`five promoters—Ericsson. Nokia.
`IBM, Toshiba and Intel—-formed a special
`interest group (SIG). The idea was to achieve
`.
`.
`_
`k
`a proper mix of business areas. two mar et
`leaders in mobile telephony, two market
`leaders in laptop computing, and a market
`leader
`in core, digital-signal-processor
`(DSP) technology. On May 20 and 21, 1998,
`the Bluetooth consortium announced itself
`to the general public from London, England;
`Sanjose, California; and Tokyo,_]apan. Since
`then, several companies have joined as
`adopters of the technology (Box B).
`to
`The. purpose of the consortium ‘is
`establish a defacta standard for the air inter-
`face and the software that controls it,
`thereby ensuring interoperability between
`devices ofdifferent manufacturers. The first
`products to use MC link technology will
`emerge at the end of 1999 in mobile phones,
`notebook
`computers
`and
`accessories
`(Figure 1).
`
`Box A
`Abbreviations
`ACL
`Asynchronous connecfiomess
`ARQ
`Automatic retransmission query
`cvso
`Continuous variable slope delta
`DSP
`Digital Signai P7009550?
`FEC
`F°'wa'd e"°' °°"e°ti°"
`FH
`Frequency hop
`FSK
`Frequency shift keying
`HEC
`Hoods, em, correction
`HPC
`Handheld personal computer
`"DA
`infrared Data A-55°°i3ti°"
`ISM
`industrial Scientific Medical
`MAC
`Medla access comm‘
`MC
`Mumcommunicator
`Pc
`Personal computer
`PDA
`i’9fS0n8i digital Bssisiflnt
`RF
`Radio frequency
`S00
`Synchronous connection-
`oriented
`special interest group
`Time division duplex
`Time diVi5i°" muiiipiex
`
`5";
`TDD
`TDM
`
`Box B
`The Bluetooth consortium—promoters and adopters
`The promoters of the Bluetooth* consortium formed a special interest group (SIG) at Ericsson
`Inc.. Research Triangle Park, North Carolina. on February 4, 1998.
`The consortium was announced to the public on May 20 and 21, 1998. Many companies have
`since joined the consortium es adopters of the technology (status as of July 11, 1998):
`
`Promoter
`Promoter
`
`Promoter
`Promoter
`Promoter
`
`Erlcsson
`Intel
`
`IBM
`Nokla
`Toshiba
`3Com
`Axis
`BreezeCOM
`Casio
`Cambridge consultantsLtd.
`CETECOM GmbH
`Cirrus Logic
`Compaq Computer Corp.
`Convergence Corporation
`Dell Computer Corp.
`|nnoLabs corporation
`Jeeves Telecom Ltd.
`Lucent Technologies UK Ltd.
`Metrlcom
`Motorola
`NaoParadigm Labs, inc.
`
`Plantronics
`Pslon
`
`Puma Technologies
`Quadriga
`Qualcomm, Inc.
`Samsung Electronics Ltd.
`Siemens Forsvarsystem A/S
`Symblan
`Symbionics Ltd.
`T-Span System
`Temic Semiconductor
`TDK
`TTP Communications Ltd.
`Universal Empowering Technologies
`VLSI Technology, inc.
`Xircom
`
`‘
`
`* The name, Bluetooth, was taken from Har-
`aid Blatand, a Danish Viking king from the
`93”)’ Middle A395-
`
`Ericsson Review No. 3, 1998
`
`111
`
`I
`I
`I
`
`i
`'
`'
`
`.
`
`;
`'
`I
`I
`|
`‘
`l
`’
`_
`_
`'
`I
`|
`I
`
`IIIIIII
`
`,
`
`
`
`
`
` amsung x. p.
`
`Samsung Ex. 1407A p. 4
`
`

`
`—o.x+to
`
`3?‘+H
`,—A
`E 5
`Ill
`4:.
`
`‘I
`625 Es
`E
`l
`1
`
`Figure 2
`Frequency-hop/time-division-duplex channel.
`
`The Bluetooth air interface
`
`The focus of user scenarios envisioned for
`first—generation products is
`typically on
`traveling business people. Portable devices
`that contain Bluetooth radios would enable
`them to leave cables and connectors at home
`(Box C). Before the air interface for Blue-
`tooth could be designed, however, certain
`requirements had to be settled:
`0 The system must operate worldwide.
`0 The connection must support voice and
`data—for instance, for multimedia appli-
`cations.
`° The radio transceiver must be small and
`operate at low power. That is, the radio
`must fit into small, portable devices, such
`as mobile phones, headsets and personal
`digital assistants (PDA).
`
`Box C User scenarios
`
`Three-In-one phone—use the same phone
`everywhere
`When you are at the offlce, your phone func-
`tions as an Intercom (no telephony charge).
`At home,
`it functions as a cordless phone
`(fixed-line charge). When you are on the move,
`it functions as a mobile phone (cellular
`charge).
`
`Internet br|dge—eurfthe intemet regardless
`of the connection
`Use your portable PC to surf the Internet any-
`where, regardless of whether you are con-
`nected wlrelessly through a mobile phone (cel-
`lular) or through a wired connection (PSTN,
`ISDN, LAN, xDSL).
`
`interactive conierence—connect every par-
`ticipant for instant data exchange
`In meetings and at conferences, you can
`share information instantly with other partici-
`pants. You can also operate a projector
`remotely without wire connectors.
`
`The ultimate headset—a cordless headset
`keeps your hands free
`Connect a headset to your mobile PC or to any
`wired connection and free your hands for more
`Important tasks at the offlce or in your car.
`
`Portable Pc speakerphone
`Connect cordless headsets to your portable
`PC and use it as a speakerphone regardless
`of whether you are in the offlce. your car, or
`at home.
`Briefcase trick (hidden computing 1)
`Access e-mall while your portable PC is still in
`
`112
`
`the briefcase. when your portable PC
`receives an e-mall message, you will be noti-
`fied by your mobile phone. You can also use
`the phone to browse Incoming email and read
`messages.
`
`Forbidden message (hidden computing 2)
`Compose e-mall on your PC while you are on
`an airplane. When you land and are allowed
`to switch on your mobile phone, the messages
`are sent immediately.
`
`Automatic synchronization (hidden
`computing 3)
`Automatically synchronize your desktop com-
`puter, portable PC, notebook (PDA or HPC) and
`mobile phone. As soon as you enterthe office,
`the address list and calendarln yournotebook
`automatically updates the files on your desk-
`top computer or vice versa.
`
`Instant postcard—send photos and video
`clips instantly from any location
`Connect a camera cordlessly to your mobile
`phone or to any wlrebound connection. Add
`comments from your mobile phone, a note
`book, or portable PC and send them instant-
`ly to a recipient anywhere in the world. Sult-
`able for professional and personal use.
`
`cordless desktop—connect all peripheral
`tools to your PC or the LAN
`Connect your desktop/laptop computer cord-
`lessly to printers, scanners and the LAN.
`Increase your sense of freedom through
`cordless mouse and keyboard connections to
`your PC.
`
`License-free band
`
`the required fre-
`To operate worldwide,
`quency band must be available globally.
`Further, it must be license-free and open to
`any radio system. The only frequency band
`that
`satisfies
`these
`requirements
`is
`at 2.45 GHz—the Industrial-Scientific-
`Medical (ISM) band, which ranges from
`2,400 to 2,483.5 MHz in the US and Eu-
`rope (only parts of this band are available in
`France and Spain), and from 2,471 to
`2,497 MHz in Japan. Consequently,
`the
`system can be used worldwide, given that
`the radio transceivers cover the frequency
`band between 2,400 and 2,500 MHz and
`that they can select the proper segment in
`this band.
`
`Frequency hopping
`Since the ISM band is open to anyone, radio
`systems operating in this band must cope
`with several unpredictable sources of inter-
`ference, such as baby monitors, garage door
`openers, cordless phones and microwave
`ovens (the strongest source of interference).
`Interference can be avoided using an adap-
`tive scheme that finds an unused part of the
`spectrum, or it can be suppressed by means
`of spectrum spreading. In the US, radios op-
`erating in the 2.45 GHz ISM band are re-
`quired to apply spectrum—spreading tech-
`niques if their transmitted power levels ex-
`ceed 0 dBm.
`Bluetooth radios use frequency-hop (FH)
`spread spectrum, since this technology bet-
`ter supports low-cost, low-power radio im-
`plemcnrations. Frequency—hop systems di-
`vide the frequency baml into several hop
`channels. During a connection, radio trans-
`ceivers hop from one channel to another in
`a pseudo-random fashion. The instanta-
`neous
`(hop)
`bandwidth
`is
`small
`in
`, frequency-hop radios, but spreading is usu-
`' ally obtained over the entire frequency band.
`This results in low-cost, narrowband trans-
`ceivers with maximum immunity to inter-
`ference. Occasionally, interference jams a
`hop channel,
`catzsing faulty reception.
`When this occurs, error-correction schemes
`in the link restore bit errors.
`
`Channel deflnition
`frequency-
`a
`use
`Bluetooth
`channels
`|1opl'time—tlivisiomduplex(I'Hl‘TDD)scl1cmI=
`(Figure 2). The channel
`is divided inm
`625 psintervals—callecl s|uts~whereadif-
`ferent hop frequency is used for each slot.
`This gives a nominal hop rate of 1.600 I10!-‘5
`put second. 011:: packet can be transmitted
`
`Ericsson Review No. 3. 1998
`
`
`
`
`p.
`
`amsung x.
`
`Samsung Ex. 1407A p. 5
`
`

`
`—- Hop
`
`Hop selectlon scheme: In the selectlon box,
`the master ldentlty selects the sequence,
`and the clock selects the phase.
`comblned, they give the hop carrler to be
`
`Flgure3
`used.
`
`I
`‘
`
`I-Io|J selectlon
`
`
`
`Phase
`Se . name
`
`Offset
`
`Mrs.-1r«u.,gq':fi
`
`-
`
`Parameters
`Modulatlon
`Peak data rate
`RF bandwidth
`RF band
`RF carrlers
`Carrier spacing
`
`Values
`G-FSK. h S 0.35
`1 Mblt/s
`220 kHz (—3dB). 1 MHz (-20 dB)
`2.4 GHz, ISM band
`23/79
`1 MHz
`5 20 dBm
`
`Peak TX puwetiiiifill
`
`three-bit media-access-control (MAC) ad-
`dress, packet type, flow control bits, bits for
`the automatic-retransmission-q uery (ARQ)
`scheme and a header-error-check (HEC)
`field (Figure 5). The header, whose length
`is fixed at 54 bits, is protected by a one-third
`rate forward-error-correction (FEC) code.
`Payload may or may not trail the header.
`The length of the payload may vary from 0
`to 2,745 bits.
`To support high data rates, multi-slot
`packets have been defined. A packet can
`cover one slot, three slots, or five slots. Pack-
`ets are always sent on a single-hop carrier.
`For multi-slot packets, the hop carrier is
`used as applied in the first slot. After the,
`multi-slot packet, the channel continues on
`the hop as dictated by the master clock. For
`example, let us consider four slots: k, 12+ 1,
`l=.+2 and 12+ 3. Ordinarily, these would be as-
`sociated with hop frequencies /1,, _f,e+1, f},_+2
`and f,,+3. However, a three-slot packet that
`starts in slot 1: uses fk for the entire packet.
`The next packet begins in slot k+3 and uses
`fk+5'
`
`Physlcal llnk dellnltlon
`Two types of link have been defined for sup-
`porting multimedia applications that mix
`voice and data:
`
`Table 1
`Radio parameters.
`
`72 b
`
`Access
`code
`
`l
`D2745 IJit5
`I
`54 bits
`E: .
`Packet
`Payload
`header
`
`Flgure 4
`Flxed packet format.
`
`Flgure 5
`Header flelds.
`
`3
`
`4
`
`1
`
`1
`
`0 synchronous con nection-oriented (SCO)
`link;
`
`
`
` amsung x. p.
`
`
`
`per interval/slot. Subsequent slots are alter-
`nately used for transmitting and receiving,
`which results in a TDD scheme.
`Two or more units sharing the same chan-
`nel form a piconet, where one unit acts as a
`master, controlling traffic on the piconet,
`and the other units act as slaves. The
`
`frequency-hop channel is determined by the
`frequency-hop sequence (the order in which
`hops are visited) and by the phase in this se-
`quence. In Bluetooth, the sequence is de-
`termined by the identity of the piconet mas-
`ter and phase is determined by the master
`unit's system clock (Figure 3). In order to
`create the master clock in the slave unit, the
`slave may add an offset to its own native
`clock. The
`repetition interval of
`the
`frequency-hop sequence, which is very long
`(more than 23 hours), is determined by the
`clock. If every participant on a given chan-
`nel uses the same identity and clock as input
`to the hop-selection box, then each unit will
`consistently select the same hop carrier and
`remain synchronized. Every piconet has a
`unique set of master parameters which cre-
`ate a unique channel.
`The channel makes use of several, equal-
`ly spaced, 1 MHz hops. With Gaussian-
`shaped frequency shift keying (FSK) modu-
`lation, a symbol rate of 1 Mbit/s can be
`achieved. In countries where the open band
`is 80 MHz or broader, 79 hop carriers have
`been defined. In countries where the band
`is narrower (Japan, France, and Spain), only
`23 hop carriers have been defined (Table 1).
`On average, the frequency-hop sequence vis-
`its each carrier with equal probability.
`
`Packet definltlon
`
`In each slot, a packet can be exchanged be-
`tween the master unit and one of the slaves.
`Packets have a fixed format (Figure 4). Each
`packet begins with a 72-bit access code that
`is derived from the master identity and is
`unique for the channel. Every packet ex-
`changed on the channel is preceded by this
`access code. Recipients on the piconet com-
`pare incoming signals with the access code.
`If the two do not match, the received pack-
`er is not considered valid on the channel and
`the rest of its contents are ignored. Besides
`packet identification, the access code is also
`used for synchronization and compensating
`for offset. The access code is very robust and
`resistant to interference. Correlationofthe ac-
`
`cess code by recipients provides similar pro-
`cessing gains as direct-sequence spreading.
`A header trails the access code. It contains
`
`important control information, such as a
`
`Ericsson Review No. 3, 1998
`
`IlI1II III Ii IIIII1II II I
`
`Samsung Ex. 1407A p. 6
`
`

`
`Type
`DM1
`DH1
`HE
`DM3
`DH3
`
`Symmetric
`(kblt/s)
`108.8
`172.8
`256.0
`384.0
`286.7
`
`Ellflm IIJUEJ
`
`Asymmetric
`(kblt/s)
`108.8
`I 108.8 l
`172.8
`172.8 '
`54.4
`384.0
`86.4
`576.0
`36 3
`477.8
`721.0
`
`IJUE
`
`
`
`-I9E(D M
`Achlevable data rates (In kblt/s) on the ACL
`llnk.
`
`Flguve 6
`S00 and ACL llnks In a piconet with one
`master and two slaves.
`
`9 asynchronous connectionless (ACL) link.
`SCO links support symmetrical, circuit-
`switched, point-to-point connections typi-
`cally used for voice. These links are defined
`on the channel by reserving two consecutive
`slots (forward and return slots) at fixed in-
`tervals.
`
`ACL links support symmetrical or asym-
`metrical,
`packet-switched,
`point-to-
`multipoint connections typically used for
`bursty data transmission. Master units use
`a polling scheme to control ACL connec-
`tions.
`
`A set of packets has been defi ned for each
`physical link.
`0 For SCO links, three kinds of single-slot
`voice packet have been defined, each of
`which carries voice at a rate of 64 kbit/s.
`Voice is sent unprotected, but if the SCO
`interval
`is decreased, a forward-error-
`correction rate of 2/3 or 1/3 can be se-
`lected.
`0 For ACL links, 1-slot, 3-slot, and S-slot
`data packets have been defined. Data can
`be sent either unprotected or protected by
`a 2/3 forward—error-correction rate. The
`maximum data rate—721 kbit/s in one
`direction and 57.6 kbit/s in the reverse di-
`rection—is obtained from an unprotect-
`ed, S-slot packet. Table 2 summarizes the
`data rates that can be obtained from ACL
`links. DMx represents x-slot, FEC-
`encoded data packets; DI-Ix represents un-
`protected data packets.
`Figure 6 depicts mixed SCO and ACL links
`on a piconet with one master and two slaves.
`Slave 1 supports an ACL link and an SCO
`link with a six-slot SCO interval. Slave 2
`only supports an ACL link. Note: slots may
`be empty when no data is available.
`
`Interference lmmunlty
`As mentioned above, the Bluetooth radio
`must operate in an open band that is sub-
`
`L . fL_li
`l SCO 1
`ACL
`
`..l -i
`isms Ml
`
`Slave1 -4 —I-
`
`I ml" ml
`
`S|ave2
`
`114
`
`i—— I
`
`-i— :
`
`l3.s_.
`
`
`
`-———-—u-IR.4
`
`ject to considerable uncontrolled interfer-
`ence. Thus, the air interface has been opti-
`mized to deal with interference.
`0 Frequency hopping techniques are ap-
`plied with a high hopping rate and short
`packet lengths (1,600 hops/s for single-
`slot packets). If a packet is lost, only a
`small portion of the message is lost.
`0 Packets can be protected by forward error
`control.
`
`0 Data packets are protected by an ARQ
`scheme in which lost data packets are au-
`tomatically retransmitted. The recipient
`checks each received packet for errors. If
`errors are detected, it indicates this in the
`header of the return packet. This results
`in a fast ARQ scheme—delays are only
`one slot in duration, and only packets that
`have been lost need to be retransmitted.
`0 Voice is never retransmitted. Instead, a ro-
`bust voice-encoding scheme is used. This
`scheme, which is based on continuous
`variable slope delta (CVSD) modulation,
`follows the audio waveform (Figure 7) and
`is very resistant to bit errors—errors are
`perceived as background noise, which in-
`tensifies as bit errors increase.
`
`Networking
`Plconets
`Bluetooth units that are within range ofeach
`other can set up ml /J06 connections. In prin-
`ciple, each unit is a peer with the same hard-
`ware capabilities (unlike cellular systems,
`there is no distinction between terminals
`and base stations). Two or more Bluetooth
`units that share a channel form a piconet. To
`regulate u';imc on the clinruiel, one of tlic
`part1c1p:1ti11g units becomes :1 master uf the
`piconet. Any unit can become :1 master, but
`by tlefinition, the unit that establlslms the
`. piconet assumes this role. All other partici-
`pants are slaves. Participants may change
`roles if a slave unit wants to take over the
`master role. Nonetheless, only one master
`may exist in a piconet at any time.
`Every unit in the piconet uses the master
`identity and clock to track the hopping
`clmnnel. Each unit also [ms its own (native).
`free-running clock. V/hen a connection is
`established, a clock offset is added to syn-
`chronize the slave clock with the master
`clock. The native clock is never adjusted.
`however, and offsets are solely valid for the
`duration of the connection.
`Master units control all traffic on a chan-
`nel. They allocate capacity for SCO links by
`reserving slots. For ACL links, they use a
`
`Erlcsson Review No. 3. 1998
`
`
`
`
`p.
`
`amsung x.
`
`Samsung Ex. 1407A p. 7
`
`

`
`
`
`11000000101111101000O111000101010 . .
`
`.
`
`.
`
`. ..
`
`Figure 7
`continuous variable slope delta (CV50) wave-
`form coding.
`
`space of 10 ms. The 10 ms train of access
`codes on different hop carriers is transmit-
`ted repeatedly until the recipient responds
`or a time-out is exceeded.
`
`When a paging unit and recipient select
`the same wake-up carrier, the recipient re-
`ceives the access code and returns an ac-
`knowledgement. The paging unit
`then
`sends a packet containing its identity and
`its current clock. After the recipient ac-
`knowledges this packet, each unit uses the
`paging unit's parameters for hop selec-
`tion—-thereby establishing a piconet
`in
`which the paging unit acts as the master.
`To establish a connection, the paging unit
`must obtain the identity of units within
`transmission range. Therefore, it executes an
`inquiry procedure: the paging unit trans-
`mits an inquiry access code (which is com-
`mon to all Bluetooth devices) on the inquiry
`wake-up carriers. When a recipient receives
`the inquiry, it returns a packet containing
`its identity and clock—the very opposite of;
`the paging procedure. After having gath-
`ered each response, the paging unit can then
`select a specific unit to page (Figure 8).
`
`scattemet
`
`Users of a channel must share capacity. Al-
`though channels are 1 MHz wide, as more
`and more users are added, throughput per
`user quickly drops to less than a few tens of
`kbit/s. Furthermore, although the medium
`available bandwidth is 80 MHz in the US
`and Europe (slightly less in Japan, France
`and Spain), it cannot be used efficiently
`when every unit must share the same 1 MHz
`hop channel. Therefore, another solution
`was adopted.
`
`Figure 8
`connection-establishment procedure and
`maximum time associated with establishing
`a connection.
`
`r‘\
`Iilnquiry)-—>
`~-
`\
`,
`5.12 s
`15.36 s
`
`Typical
`Max.
`
`.
`
`Page —I-
`_
`_
`.-
`0.64 s
`0.1-300 minutes
`7.68 s
`—
`
`115
`
`polling scheme. A slave is only permitted to
`send in the slave-to-master slot when it has
`been addressed by its MAC address in the
`preceding master-to-slave slot. A master- to-
`slave packet implicitly polls the slave; that
`is, an ordinary traffic packet addressed to a
`slave polls the slave automatically. If no in-
`formation to the slave is available, the mas-
`ter can use a POLL packet to poll the slave
`explicitly. POLL packets consist ofan access
`code and header only. This central polling
`scheme eliminates collisions between slave
`transmissions.
`
`Establishing connection
`When units are not participating in a picc-
`net, they enter standby mode, from which
`state they periodically listen for page mes-
`sages. From the total set of 79 (23) hop car-
`riers, a subset of 32 (16) wake-up carriers
`has been defined. The subset, which is cho-
`sen pseudo-randomly, is determined by the
`unit identity. Over the wake-up carriers, a
`\vake-up sequence visits each hop carrier
`once: the sequence length is 32 (16) hops.
`Every 2,048 slots (1.28 s), standby units
`move their wake-up hop carrier forward one
`hop in the wake-up sequence. The native
`clock of the unit determines the phase of the
`wake-up sequence. During the listening in-
`terval, which lasts for 18 slots or 11.25 ms,
`the unit listens on a single wake-up hop car-
`rier and correlates incoming signals with the
`access code derived from its own identity. If
`the correlator triggers—that is, if most of
`the received bits match the access code—the
`unit
`activates
`itself
`and
`invokes
`a
`connection-setup procedure. Otherwise, the
`unit returns to sleep until the next wake-up
`event.
`
`Units connecting to a unit in standby
`mode must know the stand by unit's identi-
`ty and preferably its native clock
`0 to generate the required access code
`(which constitutes the paging message);
`0 to derive the wake-up sequence;
`0 to predict the phase of this sequence.
`Since paging units cannot accurately know
`the native clock ofa recipient, they must re-
`solve the time-frequency uncertainty. They
`do so by transmitting the access code con-
`tinuously—not only in the hop in which
`they expect the recipient to wake up, but
`also in hops before and after. For a period of
`10 ms, paging units transmit the access code
`sequentially on several hop frequencies
`around the expected hop carrier. Note: the
`access code is only 72 bits long (72 ms).
`Therefore, many codes can be sent in the
`
`Ericsson Review No. 3, 1998
`
`II ii IiIII
`
`IIIIIII IIIII IIIIII IIIIII IIII I IIIIII IIII IIIII
`
`i
`
` msungxWmw
`
`Samsung Ex. 1407A p. 8
`
`

`
`piconer need only be shared by users of that
`piconer. Because individual piconets hop
`differently, different piconets can simulta-
`neously use different hop channels. Conse-
`quently, units in one piconer do not share
`their 1 MHz channel with units in another
`
`(the
`piconer. The aggregate throughput
`total throughput accumulated over all pi-
`conets) increases as more piconets are added.
`Collisions do occur, however, when two pi-
`conets use the same hop channel simultane-
`ously. As the number of piconets increases,
`performance in the frequency-hop system
`degrades gracefully. Simulations of a scar-
`ternet consisting of 10 piconets indicate that
`reduction in throughput per piconer is less
`than 10%. In the scatternet, the radio medi-
`um is shared; in a piconer, the channel and
`information are shared.
`Since every piconer uses the same band-
`width, each shares the 80 MHz in an aver-
`age sense. Provided they select different hop
`channels, however, no two piconets must si-
`multaneously share the same 1 MHz chan-
`nel.
`Let us assume there are 100 users. If each
`
`belonged to the same network, all 100 users
`would have to share the same 1 MHz chan-
`nel. Thus, average throughput per user
`would be 10 kbit/s and aggregate through-
`put would be 1 Mbit/s. However, if not
`everyone wanted to talk to each other, we
`could split the piconet into independent
`piconets. For example, if the users separat-
`ed themselves into groups of five, then we
`could create 20 independent piconets. Witli
`only five users sharing the 1 MHz hop chan-
`nel,
`throughput per user
`increases
`to
`200 kbit/s and aggregate throughput in-
`creases to 20 Mbit/s. Obviously, this as-
`sumes ideal conditions, where no two pico-
`nets select the same hop channel at the same
`, time. In reality—because the piconets hop
`independently—collisions will occur,
`re-
`ducing effective throughput. Nonetheless,
`the final throughput obtained from multi-
`ple piconets exceeds that ofa single piconer.
`The maximum number of units that can
`
`actively participate on a single piconer is
`eight: one master and seven slaves. The
`MAC address in the packet header, which is
`used to distinguish each unit, is limited to
`three bits. Figure 9 illustrates the scatternet
`approach applied to the scenario shown in
`Figure 1.
`
`Inter-plconet communlcatlon
`Different piconets
`adhere
`to different
`frequency-hop sequences and are controlled
`
`Ericsson Review No. 3. 1995
`
`amsung x.
`
`p.9
`
`
`
`-'
`
`J’
`\
`
`~.___
`Headset
`
`I
`"
`
`h‘
`
`Access point
`I
`
`I
`“"""‘"
`
`____,
`
`
`
`Figure 9
`A scatternet of four piconets applied to the
`scenario described In Figure 1.
`
`Units that share the same area and that
`are within range of one another can poten-
`tially esrnblish ad /10: connections between
`themselves. However, only those units that
`truly want to exchange information share
`the same channel (piconer). This solution
`permits several piconets to be created with
`overlapping areas of coverage. Each piconer
`adheres
`to its own hopping sequence
`through the 80 MHz medium. The channel
`in each piconet hops pseudo-randomly over
`the carriers in the 80 MHz band. The users
`
`in each piconer have only a 1 MHz hop chan-
`nel at their disposal.
`A group of piconets is called a scatternet.
`Aggregate and individual
`throughput of
`users in a scatternet is much greater than
`when each user participates on the same pi-
`conet with a 1 Mbit/s channel. Additional
`gains are obtained by statistically multi-
`plexing hop channels and by reusing chan-
`nels. The 1 MHz hop channel in any given
`
`Hop selection
`
`Native CLK