`
`
`
`111111101111101111111111111011!1,1111,111111,11!1,111141,11111111111111111111111110111111
`
`(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2006/0120433 Al
`Jun. 8, 2006
`Baker et al.
`(43) Pub. Date:
`
`(54) COMMUNICATIONS SYSTEMS AND
`METHODS
`
`(76)
`
`Inventors: David Baker, Cambridgeshire (GB);
`Mark Justin Moore, Cambridgeshire
`(GB)
`
`Correspondence Address:
`MILLEN, WHITE, ZELANO & BRANIGAN,
`P.C.
`2200 CLARENDON BLVD.
`SUITE 1400
`ARLINGTON, VA 22201 (US)
`
`(21) Appl. No.:
`
`10/516,747
`
`(22) PCT Filed:
`
`May 21, 2004
`
`(86) PCT No.:
`
`PCT/GB04/02201
`
`Related U.S. Application Data
`
`(60) Provisional application No. 60/518,327, filed on Nov.
`10, 2003.
`
`(30)
`
`Foreign Application Priority Data
`
`May 28, 2003
`
`(GB)
`
` 0312197.7
`
`Publication Classification
`
`(51) Int. Cl.
`HO4B 1/69
`(52) U.S. Cl.
`
`(2006.01)
`
`(57)
`
`ABSTRACT
`
`375/130
`
`This invention generally relates to networks of communi-
`cations devices, in particular ultra wideband (UWB) com-
`munications devices. An ultra-wideband (UWB) network
`comprising a plurality of UWB devices each forming a node
`of said network, pairs of said IJWB devices being configured
`for communication with one another using one of a plurality
`of UWB channels, each said UWB device comprising a
`UWB transceiver for bidirectional conununication over one
`or more of said UWB channels with at least one other of said
`UWB devices; and a device controller coupled to said UWB
`transceiver, said controller being configured to determine a
`said UWB channel for use in establishing a communication
`link with each other UWB device; whereby said network is
`configured for automatic construction of a set of communi-
`cations links between said nodes of said network.
`
`/ 606a
`
`604
`
`/ 602
`
`PROGRAM
`MEMORY
`
`IF\
`/
`\r-i/
`
`PROCESSOR
`
`DATA
`MEMORY
`
`606b
`
`CONTROL
`BUS
`
`608
`
`/ 616
`
`DATA
`BUS
`
`610
`
`610a
`
`DMA CONTROLLER
`
`614
`
`RADIO INTERFACE
`(UWB)
`
`TO OTHER
`NODES
`610b
`
`616
`
`/
`
`PACKET BUFFER
`MEMORY
`
`ADDITIONAL
`MEMORY
`
`618
`
`620
`
`800
`
`/ 612
`
`SECOND
`INTERFACE (PCI)
`
`TO HOST
`PROCESSOR
`
`Sonos Ex. 1004, p. 1
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 1 of 16
`
`US 2006/0120433 Al
`
`104
`
`/ 106
`
`BPF
`
`/ 114
`
`/116
`
`/118
`
`120\
`
`LNA/AGC
`
`MF/CORR
`
`ADC
`
`/ 112
`
`/ 108
`
`DRIVER -4 --
`
`IMPULSE GEN
`
`/ 110
`
`Ax
`-111- — DATA
`OUT
`TO BASEBAND
`PROCESSING
`
`Tx DATA IN
`
`Figure 1a
`
`124
`
`/ 132
`
`Mod
`(110)
`
`126
`
`/ 34
`
`BPF
`
`130
`
`BPF
`
`128
`
`140
`
`)1'
`ATTN
`
`\ 136
`
`138
`
`
`
`PA
`•
`
`GATE
`
`122 /
`
`Figure 1 b
`
`c i128
`
`140
`
`BPF
`
`\ 130
`
`138
`
`PA
`
`GATE
`
`Figure I c
`
`Sonos Ex. 1004, p. 2
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 2 of 16
`
`US 2006/0120433 Al
`
`c5 124
`
`
`
`/ 144
`
`L34
`
`TIME GATE
`
`BPF
`
`ATTN
`
`.- 132
`
`Mod
`(f/45)
`
`/ 146
`
`TRIGGER
`
`\ 136
`
`142
`
`Figure ld
`
`140
`
`138
`
`PA
`
`GATE
`
`152
`
`/ 160
`
`CODE
`GENERATOR
`
`/156
`
`PRECISION
`TIMING
`GENERATOR
`
`/ 54
`
`/ 150
`
`PULSER
`
`148
`
`/ 158
`
`TIME
`BASE
`
`DATA
`IN
`
`Figure le
`
`/ 176
`
`7178
`
`/ 172
`
`TEMPLATE
`GEN
`
`TRACKING
`LOOP
`
`170
`
`/ 180
`
`DETECTOR
`
`DATA
`OUT
`
`164
`
`PRECISION TIMING
`GENERATOR
`
`TIME
`BASE
`
``166
`
`/ 168
`
`CODE
`GENERATOR
`
`Figure If
`
`162
`
`Sonos Ex. 1004, p. 3
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 3 of 16
`
`US 2006/0120433 Al
`
`Rx
`
`186
`
`LNA
`
`/ 188
`
`/190
`
`CORR
`
`-4--
`
`CODE SEQ GEN
`
`T
`
`/ 202
`
`Tx ANT
`OVR
`
`192
`
`200 r RTC
`
`194`
`
`/182
`
`7\
`
`/ 196
`PROCESSOR
`
`7
`MEMORY
`
`/ 198
`
`Figure lg
`
`POWER
`
`/ 212
`
`/ 210
`
`L
`
`210
`
`/ 214R
`
`Tx ANT
`
`210
`
`'4\210
`
`GND
`
`20/
`
`Figure lh
`
`Figure 2g
`
`Figure 2h
`
`Sonos Ex. 1004, p. 4
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 4 of 16
`
`US 2006/0120433 Al
`
`POWER
`
`Figure 2a
`
`Figure 2b
`
`POWER
`
`:
`
` t
`
`Figure 2c
`
`Figure 2d
`
`POWER
`
`V
`
`+1
`
`►1
`
`
`
`
`
` t
`
`to
`Figure 2e
`
`(w12) 1
`
`4
`
`
`
`f
`
`Figure 2f
`
`Sonos Ex. 1004, p. 5
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 5 of 16
`
`US 2006/0120433 Al
`
`316
`
`Satellite
`Receiver
`320
`
`308
`
`312
`
`306
`
`310
`
`302
`
`304
`
`
`
` 4,--S-4'
`.
`
`Laptop
`computer
`
`Printer
`
`ir
`
`,.,r
`320 1
`
`Television 2
`NthJi
`VideolDVD
`
`314
`
`/
`
`320
`
`\i
`
`/ 318
`
`\stm5/01---\—*
`4---_____\--------4,
`Jr)!
`Video
`Camera Audio System
`
`r
`
`Television 1
`fr ."...„,mr--
`Set Top Box
`
`300
`
`Figure 3a
`
`350
`
`1
`
`360
`
`362
`
`352
`
`2
`
`4
`
`356
`
`3
`
`354
`
`Figure 3b
`
`Sonos Ex. 1004, p. 6
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 6 of 16
`
`US 2006/0120433 Al
`
`/ 404
`
`UWB NETWORK DEVICE
`
`412
`
`VIDEO
`
`DIGITAL
`INTERFACE
`
`UWB
`
`406
`
`1 408
`
`410/
`
`Figure 4a
`
`\ 402
`
`412
`
`400
`
`/ 416
`
`OTHER PROCESSOR
`
`2-PORT MAC LEVEL
`BRIDGE
`
`PCI
`
`--- 414
`
`412
`
`UWB
`NETWORK
`DEVICE
`
`410
`
`UW8
`
`412
`
`420 7
`
`402 i
`
`Figure 4b
`
`Sonos Ex. 1004, p. 7
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 7 of 16
`
`US 2006/0120433 Al
`
`500
`
`502a
`
`504a
`
`502
`
`/
`
`504
`
`UWB
`
`2
`
`PCI
`
`502b
`
`504b
`
`Figure 5a
`
`552a
`
`552
`
`554a
`
`Z i
`
`1554
`I
`
`UWB
`
`2
`
`PCI
`
`552b
`
`554b
`
`556b
`
`558b
`
`/ 556
`
`PCI
`
`4
`
`UWB
`
`/ 558
`
`UWB
`
`1
`
`PCI
`
`UWB
`
`1
`
`PCI
`
`PCI
`
`3
`
`UWB
`
`550 /
`
`556a
`
`Figure 5b
`
`558a
`
`Sonos Ex. 1004, p. 8
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 8 of 16
`
`US 2006/0120433 Al
`
`/ 606a
`
`PROGRAM
`MEMORY
`
`/ 602
`
`604
`
`PROCESSOR
`
`DATA
`MEMORY
`
`/ 606b
`
`DATA
`BUS
`
`616
`
`DMA CONTROLLER
`
`614
`
`/ 616
`
`/
`
`618
`
`PACKET BUFFER
`MEMORY
`
`ADDITIONAL
`MEMORY
`
`620
`
`A
`
`CONTROL
`BUS
`
`608
`
`1 610
`
`610a
`
`RADIO INTERFACE
`(UWB)
`
`TO OTHER
`NODES
`610b
`
`/ 612
`
`SECOND
`INTERFACE (PCI)
`
`(
`
`....t> TO HOST
`PROCESSOR
`
`600 /
`
`Figure 6
`
`Sonos Ex. 1004, p. 9
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 9 of 16
`
`US 2006/0120433 Al
`
`/ 700
`
`PREAMBLE
`
`702
`
`DATA
`
`/ 704
`
`CRC
`
`706
`
`DST
`
`708
`
`SRC
`
`/ 710
`LENGTH/
`TYPE
`
`/ 712
`
`714
`
`LLC/SNAP
`
`IP DATAGRAM
`
`712
`
`716
`
`714
`
`LLC/SNAP
`
`CHANNEL
`
`IP DATAGRAM
`
`Figure 7a
`
`CHANNEL HANDLE
`
`FRAGMENTATION FLAGS
`
`CRC
`
`CHANNEL NUMBER
`
`716
`
`Figure 7b
`
`Sonos Ex. 1004, p. 10
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 10 of 16
`
`US 2006/0120433 Al
`
`S800
`NODE SWITCHED ON AND
`DETERMINES NAME AND
`ADDRESS
`
`S802
`NODE SENDS ALERT PACKET
`TO NETWORK ON BROADCAST
`CHANNEL
`
`S804
`NO
`RESPONSE NODE LISTENS FOR RESPONSE
`ON BROADCAST CHANNEL AND
`WAITS UNTIL TIMEOUT
`
`RESPONSE
`RECEIVED
`
`S806
`
`NODE CHOOSES NEW NAME/
`ADDRESS
`
`S808
`END
`
` (
`
`Figure 8
`
`Sonos Ex. 1004, p. 11
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 11 of 16
`
`US 2006/0120433 Al
`
`S900
`
`DISCOVER DEVICE ON NETWORK
`
`ESTABLISH CONNECTION
`
`S902
`
`S904
`
`SEND DATA
`
`Figure 9
`
`S1002
`SEND DISCOVERY PACKET TO
`NETWORK ON BROADCAST
`CHANNEL
`
`;1004
`LISTEN FOR RESPONSE ON
`BROADCAST CHANNEL UNTIL
`TIMEOUT
`
`31004
`
`•
`
`STORE MAC ADDRESS FOR
`DEVICE
`
`Figure 10
`
`Sonos Ex. 1004, p. 12
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 12 of 16
`
`US 2006/0120433 Al
`
`S1100
`
`RECEIVE DATA FOR SENDING TO
`KNOWN NAME AND ADDRESS
`
`S1102
`
`SENDS CONNECTION REQUEST
`PACKET ON BROADCAST CHANNEL TO
`ALL DEVICES IN RANGE
`
`i
`I
`
`S1104
`
`RECEIVE CONNECTION ESTABLISHED
`PACKET FROM LOCAL DEVICE
`
`81106
`
`STORE DESTINATION ADDRESS AND
`OUTGOING PORT AND CHANNEL
`NUMBER INTO CONNECTION LINK
`TABLE
`
`Figure h 1 a
`
`Sonos Ex. 1004, p. 13
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 13 of 16
`
`US 2006/0120433 Al
`
`S1150
`RECEIVE CONNECTION REQUEST PACKET ON
`BROADCAST CHANNEL
`
`S1152
`
`S1154
`
`UPDATE QUALITY DATA
`
`DECREMENT HOP COUNT AND RESEND CONNECTION
`REQUEST PACKET TO ALL IN RANGE
`
`S1156
`
`STORE TEMPORARY CONNECTION LINK TABLE DATA
`
`S1156
`
`RECEIVE CONNECTION ESTABLISHED PACKET AND FIX
`CONNECTION LINK TABLE DATA
`
`Figure llb
`
`S1160
`
`RECEIVE CONNECTION REQUEST PACKET ON
`BROADCAST CHANNEL
`
`S1162
`
`REPLY IMMEDIATELY
`WITH CONNECTION
`ESTABLISHED
`PACKET
`
`.
`S1164
`STORES QUALITY
`DATA AND AWAIT
`NEXT INCOMING
`CONNECTION
`REQUEST WITH
`TIMEOUT
`
`S1166
`
`EVALUATE QUALITY
`DATA AND REPLY
`
`S1168
`
`STORE CONNECTION
`LINK TABLE DATA
`
`Figure 11c
`
`Sonos Ex. 1004, p. 14
` Sonos v. Google
` IPR2021-00964
`
`

`

`91 Jo 171 looqS
`
`IV ££170ZIO/900Z SR
`
`to
`ao
`
`uopuagoind uoguawldv luajud
`
`Figure 11d
`
`:21:3e:90:00: 3
`
`.
`ey!9e:
`
`0
`
`1178
`
`UWB2
`
`06-.1i36:66:b0:02
`
`eVi66:
`
`1176 /
`
`UWB1
`
`0321i3ed6:b4b
`
`!
`
`1174
`
`1172 \
`
`1170
`
`Sonos Ex. 1004, p. 15
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 15 of 16
`
`US 2006/0120433 Al
`
`S1200
`
`S1202
`
`S1204
`
`RECEIVE DATA TO BE SENT
`
`PACKETISE DATA
`
`READ OUTGOING PORT AND CHANNEL NUMBER FOR
`DESTINATION FROM CONNECTION LINK TABLE AND
`INSERT CHANNEL NUMBER INTO PACKET
`
`S1206
`
`SEND DATA PACKET TO NEXT UWB NETWORK DEVICE
`ON DETERMINED CHANNEL NUMBER AND PORT
`
`S1208
`
`Y
`
`FAILURE/DISCONNECT MESSAGE RECEIVED
`
`S1210
`
`FREE CONNECTION LINK TABLE ENTRY
`
`Figure 12
`
`Sonos Ex. 1004, p. 16
` Sonos v. Google
` IPR2021-00964
`
`

`

`Patent Application Publication Jun. 8, 2006 Sheet 16 of 16
`
`US 2006/0120433 Al
`
`5130
`
`S1302
`
`RECEIVE DATA PACKET
`
`READ CHANNEL NUMBER FROM PACKET AND
`LOOK UP OUTGOING PORT AND CHANNEL
`NUMBER
`
`ENTRY/DEVICE
`NOT FOUND
`
`RECIPIENT
`
`VALID PORT AND
`CHANNEL NO
`
`S1304
`
`S1308
`
`SEND DISCONNECT
`MESSAGE TO ORIGINATOR
`
`UPDATE PACKET CHANNEL
`NUMBER AND RE-TRANSMIT
`PACKET ON OUTGOING PORT
`AND CHANNEL NUMBER
`
`S1306
`
`DEPACKETISE AND PASS
`DATA TO RECIPIENT DEVICE
`
`Figure 13
`
`Sonos Ex. 1004, p. 17
` Sonos v. Google
` IPR2021-00964
`
`

`

`US 2006/0120433 Al
`
`Jun. 8, 2006
`
`1
`
`COMMUNICATIONS SYSTEMS AND METHODS
`[0001] This invention generally relates to networks of
`communications devices,
`in particular ultra wideband
`(UWB) communications devices.
`[0002] Techniques for UWB communication developed
`from radar and other military applications, and pioneering
`work was carried out by Dr 0. F. Ross, as described in U.S.
`Pat. No. 3,728,632. Ultra-wideband communications sys-
`tems employ very short pulses of electromagnetic radiation
`(impulses) with short rise and fall limes, resulting in a
`spectrum with a very wide bandwidth. Some systems
`employ direct excitation of an antenna with such a pulse
`which then radiates with its characteristic impulse or step
`response (depending upon the excitation). Such systems are
`referred to as "carrier free" since the resulting rf emission
`lacks any well-defined carrier frequency. However other
`UWB systems radiate one or a few cycles of a high fre-
`quency carrier and thus it is possible to define a meaningful
`centre frequency and/or phase despite the large signal band-
`width. The US Federal Communications Commission (FCC)
`defines UWB as a —10 dB bandwidth of at least 25% of a
`centre (or average) frequency or a bandwidth of at least 1.5
`GHz; the US DARPA definition is similar but refers to a —20
`dB bandwidth. Such formal definitions are useful and clearly
`differentiates UWB systems from conventional narrow and
`wideband systems but the techniques described in this
`specification are not limited to systems falling within this
`precise definition and may be employed with similar sys-
`tems employing very short pulses of electromagnetic radia-
`tion.
`[0003] UWB communications systems have a number of
`advantages over conventional systems. Broadly speaking,
`the very large bandwidth facilitates very high data rate
`communications and since pulses of radiation are employed
`the average transmit power (and also power consumption)
`may be kept low even though the power in each pulse may
`be relatively large. Also, since the power in each pulse is
`spread over a large bandwidth the power per unit frequency
`may be very low indeed, allowing UWB systems to coexist
`with other spectrum users and, in military applications,
`providing a low probability of intercept. The short pulses
`also make UWB communications systems relatively unsus-
`ceptible to multipath effects since multiple reflections can in
`general be resolved. Finally UWB systems lend themselves
`to a substantially all-digital implementation, with conse-
`quent cost savings and other advantages.
`[0004] FIG. la shows a typical UWB transceiver 100.
`This comprises an transmit/receive antenna 102 with a
`characteristic impulse response indicated by bandpass filter
`(BPF) 104 (although in some instances a bandpass filter may
`be explicitly included), couples to a transmit/receive switch
`106.
`[0005] The transmit chain comprises an impulse generator
`108 modulatable by a baseband transmit data input 110, and
`an antenna driver 112. The driver may be omitted since only
`a small output voltage swing is generally required. One of a
`number of modulation techniques may be employed, typi-
`cally either OOK (on-off keying i.e. transmitting or not
`transmitting a pulse), M-ary amplitude shift keying (pulse
`amplitude modulation), or PPM (pulse position modulation
`i.e. dithering the pulse position). typically the transmitted
`pulse has a duration of <1 us and may have a bandwidth of
`the order of gigahertz.
`
`[0006] The receive chain typically comprises a low noise
`amplifier (LNA) and automatic gain control (AGC) stage
`114 followed by a correlator or matched filter (MF) 116,
`matched to the received pulse shape so that it outputs an
`impulse when presented with rf energy having the correct
`(matching) pulse shape. The output of MF 116 is generally
`digitised by an analogue-to-digital convertor (ADC) 118 and
`then presented to a (digital or software-based) variable gain
`threshold circuit 120, the output of which comprises the
`received data. The skilled person will understand that for-
`ward error correction (FEC) such as block error coding and
`other bascband processing may also he employed, but such
`techniques are well-known and conventional and hence
`these is omitted for clarity.
`
`[0007] FIG. lb shows one example of a carrier-based
`UWB transmitter 122, as described in more detail in U.S.
`Pat. No. 6,026,125 (hereby incorporated by reference). This
`form of transmitter allows the ITWR transmission centre
`frequency and bandwidth to be controlled and, because it is
`carrier-based, allows the use of frequency and phase as well
`as amplitude and position modulation. Thus, for example,
`QAM (quadrature amplitude modulation) or M-ary PSK
`(phase shift keying) may be employed.
`
`[0008] Referring to FIG. lb, an oscillator 124 generates a
`high frequency carrier which is gated by a mixer 126 which,
`in effect, acts as a high speed switch. A second input to the
`mixer is provided by an impulse generator 128, filtered by
`an (optional) bandpass filter 130. The amplitude of the
`filtered impulse determines the time for which the mixer
`diodes are forward biased and hence the effective pulse
`width and bandwidth of the UWB signal at the output of the
`mixer. The bandwidth of the UWB signal is similarly also
`determined by the bandwidth of filter 130. The centre
`frequency and instantaneous phase of the UWB signal is
`determined by oscillator 124, and may be modulated by a
`data input 132. An example of a transmitter with a centre
`frequency of 1.5 GHz and a bandwidth of 400 MHz is
`described in U.S. Pat. No. 6,026,125. Pulse to pulse coher-
`ency can be achieved by phase locking the impulse genera-
`tor to the oscillator.
`
`[0009] The output of mixer 126 is processed by a bandpass
`filter 134 to reject out-of-hand frequencies and undesirable
`mixer products, optionally attenuated by a digitally con-
`trolled rf attenuator 136 to allow additional amplitude modu-
`lation, and then passed to a wideband power amplifier 138
`such as a MMIC (monolithic microwave integrated circuit),
`and transmit antenna 140. The power amplifier may be gated
`on and off in synchrony with the impulses from generator
`128, as described in U.S.'125, to reduce power consump-
`tion.
`
`[0010] FIG. lc shows a similar transmitter to that of FIG.
`lb, in which like elements have like reference numerals. The
`transmitter of FIG. lc is, broadly speaking, a special case of
`the transmitter of FIG. lb in which the oscillator frequency
`has been set to zero. The output of oscillator 124 of FIG. lb
`is effectively a dc level which serves to keep mixer 126
`always on, so these elements are omitted (and the impulse
`generator or its output is modulated).
`
`[0011] FIG. ld shows an alternative carrier-based UWB
`transmitter 142, also described in U.S. Pat. No. 6.026,125.
`Again like elements to those of FIG. lb are shown by like
`reference numerals.
`
`Sonos Ex. 1004, p. 18
` Sonos v. Google
` IPR2021-00964
`
`

`

`US 2006/0120433 Al
`
`Jun. 8, 2006
`
`2
`
`In the arrangement of FIG. ld a time gating circuit
`[0012]
`144 gates the output of oscillator 124 under control of a
`timing signal 146. The pulse width of this timing signal
`determines the instantaneous UWB signal bandwidth. Thus
`the transmitted signal UWB bandwidth may be adjusted by
`adjusting the width of this pulse.
`
`[0013] Ultra-wideband receivers suitable for use with the
`UWB transmitters of FIGS. lb to ld are described in U.S.
`Pat. No. 5,901,172. These receivers use tunnel diode-based
`detectors to enable single pulse detection at high speeds
`(several megabits per second) with reduced vulnerability to
`in-band interference. Broadly speaking a tunnel diode is
`switched between active and inactive modes, charge stored
`in the diode being discharged during its inactive mode. The
`tunnel diode acts, in effect, as a time-gated matched filter,
`and the correlation operation is synchronised to the incom-
`ing pulses.
`
`[0014] FIG. le shows another example of a known UWB
`transmitter 148, as described for example in U.S. Pat. No.
`6,304,623 (hereby incorporated by reference). In FIG. le a
`pulser 150 generates an rf pulse for transmission by antenna
`152 under control of a timing signal 154 provided by a
`precision timing generator 156, itself controlled by a stable
`timchasc 158. A code generator 160 receives a reference
`clock from the timing generator and provides pseudo-ran-
`dom time offset commands to the timing generator for
`dithering the transmitter pulse positions. This has the effect
`of spreading and flattening the comb-like spectrum which
`would otherwise be produced by regular, narrow pulses (in
`some systems amplitude modulation may he employed for a
`similar effect).
`
`[0015] FIG. If shows a corresponding receiver 162, also
`described in U.S.'623. This uses a similar timing generator
`164, timebase 166 and code generator 168 (generating the
`same pseudo-random sequence), but the timebase 166 is
`locked to the received signal by a tracking loop filter 170.
`The timing signal output of timing generator 164 drives a
`template generator 172 which outputs a template signal
`matching the transmitted UWB signal received by a receive
`antenna 174. A correlator/sampler 176 and accumulator 178
`samples and correlates the received signal with the template,
`integrating over an aperture time of the correlator to produce
`an output which at the end of an integration cycle is
`compared with a reference by a detector 180 to determine
`whether a one or a zero has been received.
`
`[0016] FIG. lg shows another UWB transceiver 182
`employing spread spectrum-type coding techniques. A simi-
`lar transceiver is described in more detail in U.S. Pat. No.
`6,400,754 the contents of which are hereby explicitly incor-
`porated by reference.
`
`In FIG. lg a receive antenna 184 and low noise
`[0017]
`amplifier 186 provide one input to a time-integrating corr-
`elator 188. A second input to the correlator is provided by a
`code sequence generator 190 which generates a spread
`spectrum-type code such as a Kasami code, that is a code
`with a high auto-correlation coefficient from a family of
`codes with no low cross-correlation coefficients. Correlator
`188 multiplies the analogue input signal by the reference
`code and integrates over a code sequence period and in
`U.S.'754 is a matched filter with a plurality of phases
`representing different time alignments of the input signal
`and reference code. The correlator output is digitised by
`
`analogue-to-digital converter 192 which provides an output
`to a bus 194 controlled by a processor 196 with memory 198
`the code sequence generator 190 is driven by a crystal
`oscillator driven flock 200 a transmit antenna driver 202
`receives data from bus 194 which is multiplied by a code
`sequence from generator 190 and transmitted from transmit
`antenna 204. In operation coded sequences of impulse
`doublets are received and transmitted, in one arrangement
`each bit comprising a 1023-chip sequence of 10 ns chips,
`thus having a duration of 10 µs and providing 30 dB
`processing gain. Shorter spreading sequences and/or faster
`clocks may he employed for higher hit rates.
`
`[0018] The transceiver described in U.S.'754 uses a modi-
`fication of a frequency-independent current-mode shielded
`loop antenna (as described in U.S. Pat. No. 4,506,267)
`comprising a flat rectangular conducting plate. This antenna
`is referred to as a large-current radiator (LCR) antenna and
`when driven by a current it radiates outwards on the surface
`of the plate.
`
`[0019] FIG. lh shows a driver circuit 206 for such an LCR
`transmit antenna 208. The antenna is driven by an H-bridge
`comprising four MOSFF,Ts 210 controlled by left (L) and
`right (R) control lines 212, 214. By toggling line 214 high
`then low whilst maintaining line 214 low an impulse doublet
`(that is a pair of impulses of opposite polarity) of a first
`polarity is transmitted, and by toggling line 212 high then
`low whilst holding line 214 low an impulse doublet of
`opposite polarity is radiated. The antenna only radiates
`whilst the current through it changes, and transmits a single
`gaussain impulse on each transition.
`
`[0020] FIGS. 2a to 2k show examples UWB waveforms.
`FIG. 2a shows a typical output waveform of a UWB
`impulse transmitter, and FIG. lb shows the power spectrum
`of the waveform of FIG. 2a. FIG. 2c shows a wavelet pulse
`(which when shortened becomes a monocycle) such as
`might be radiated from one of the transmitters of FIGS. lb
`to ld. FIG. 2d shows the power spectrum of FIG. 2c. FIG.
`2e shows an impulse doublet and FIG. 2f the power spec-
`trum of the doublet of FIG. 2e. It can be seen that the
`spectrum of FIG. 2f comprises a comb with a spacing (in
`frequency) determined by the spacing (in time) of the
`impulses of the doublet and an overall bandwidth deter-
`mined by the width of each impulse. Tt can also he appre-
`ciated from FIGS. 2e and 2f that dithering the pulse posi-
`tions will tend to reduce the nulls of the comb spectrum.
`FIG. 2g shows examples of basis impulse doublet wave-
`forms for a logic 0 and a logic 1. FIG. 2h shows an example
`of a TDMA UWB transmission such as might be radiated
`from the transceiver of FIG. lg, in which bursts of Code
`Division Multiple access (CDMA)-encoded data are sepa-
`rated by periods of non-transmission to allow access by
`other devices.
`
`[0021] Ultra wideband communications potentially offer
`significant advantages for wireless home networking, par-
`ticularly broadband networking for audio and video enter-
`tainment devices, because of the very high data rates which
`are possible with UWB systems. However, UWB commu-
`nications also present a number of special problems, most
`particularly the very low transmit power output imposed by
`the relevant regulatory authorities, in the US the FCC. _thus
`the maximum permitted power output is presently below the
`acceptable noise floor for unintentional emitters so that a
`
`Sonos Ex. 1004, p. 19
` Sonos v. Google
` IPR2021-00964
`
`

`

`US 2006/0120433 Al
`
`Jun. 8, 2006
`
`3
`
`UWB signal effectively appears merely as noise to a con-
`ventional receiver. "Ibis low power output limits the effective
`range of UWB communications and there is therefore a need
`to address this difficulty.
`
`[0022] The applicant has recognised that there are some
`features of UWB communications of which advantage can
`be taken to address this difficulty, in particular the ability of
`UWB to support multiple channels. Such multiple channels
`may be provided in a number of ways. For example the
`psudo-random code used in the transmitters described above
`with reference to FIGS. le and lg may be employed to
`define code division multiplexed channels in a UWB com-
`munications system. Alternatively an arrangement such as
`that described with reference to FIG. lb may be employed
`to define a plurality of UWB bands. In another approach the
`relative timing of impulse doublets in an antipodeal modu-
`lation scheme may be whitened or spread using a psudo-
`random noise (pn) sequence code, again the pn sequence
`defining a channel. Provided that the impulse doublets are
`well separated so that the mark:space ratio is small collisions
`are relatively rare and generally only result in correctable
`single bit errors, so that multiple channels can coexist within
`one broad UWB band.
`
`[0023] The ability of IJWR communications to support
`such multiple channels facilitates the implementation of a
`mesh-type network in which when one U WE device is out
`of range with another (or at least sufficiently out of range
`that communication at a desired speed or with a desired
`quality/bit error rate) communication takes place via a third,
`intermediary IJWR device within range of both the first and
`second device.
`
`In a conventional radio network such as a network
`[0024]
`based upon a standard in the IEEE802.11 series communi-
`cations between devices in the network are routed through a
`central base station which stores a routing table defining the
`topology of the entire network so that routing within the
`network can be controlled. Ilowever such an arrangement
`suffers from a number of defects in a wireless home net-
`working environment, one important defect being the need
`to reconfigure the base station routing table whenever the
`network configuration changes. In a home environment it is
`undesirable to have to configure a router when the network
`topology changes, particularly as devices may be frequently
`added to or removed from the network, for example simply
`by switching on and off a network-enabled television or
`video recorder.
`
`[0025] Furthermore the base station of such a network
`constitutes a single point of failure of the network, which
`again is undesirable. A still further difficulty is the relatively
`large memory and processing requirements of current net-
`work protocols
`typically equivalent computing power to a
`500 megahertz Pentium (trademark) is required to imple-
`ment a networking protocol of this type, whereas an inte-
`grated circuit to enable wireless home networking should
`preferably retail in quantity for under $10.
`
`[0026] According to a first aspect of the present invention,
`there is therefore provided an ultra-wideband (UWB) net-
`work comprising a plurality of UWB devices each forming
`a node of said network, pairs of said UWB devices being
`configured for communication with one another using one of
`a plurality of UWB channels, each said UWB device com-
`prising a UWB transceiver for bidirectional communication
`
`over one or more of said UWB channels with at least one
`other of said UWB devices; and a device controller coupled
`to said UWB transceiver, said controller being configured to
`determine a said UWB channel for use in establishing a
`communication link with each other UWB device; whereby
`said network is configured for automatic construction of a
`set of communications links between said nodes of said
`network.
`
`In embodiments employing UWB channels to
`[0027]
`establish communication links within the network this effec-
`tively allows the construction of virtual circuits within the
`network for communication between nodes. Thus where first
`and second devices are communicating via an intermediary
`the intermediary can communicate with the first device
`using a first channel and with the second device using a
`second channel, the intermediary acting as a store and
`forward node for data communicated between the first and
`second devices. In this way the intermediary need only be
`locally aware
`that is no single device requires a map of the
`global network structure (or changes in this) because routing
`can be performed without such a map. Each intermediary
`device merely knows that incoming data on one channel
`(and/or port) should be forwarded on a second channel
`and/or port), such a list of associated channels being locally
`stored, for example as a table. In this way data is forwarded
`through the network until reaching its intended recipient.
`
`[0028] To determine the data for these locally stored tables
`a broadcast protocol may be employed, for example a first
`device broadcasting a connection request to a second device
`throughout the network, the second device responding when
`it receives the connection request. 'thus each device is
`preferably configured for broadcasting such a connection
`request, that is for forwarding the connection request to
`substantially all other nodes within range except that from
`which the request was received. The skilled person will
`recognise that such a technique has the potential to consume
`a significant fraction of the network bandwidth. However,
`the technique is practical in wireless home networks because
`such networks are generally relatively small and thus broad-
`cast traffic, overall, need not have a great impact upon
`network availability.
`
`[0029] A similar broadcast arrangement can be employed
`to alert devices within the network when a new device
`connects, for example when a network-enabled television is
`switched on. This initial broadcast can also be used to
`determine a unique identifier for the new device within the
`network such as a device name and/or address.
`
`[0030] The skilled person will recognise that one charac-
`teristic of embodiments of the above described networks is
`their essentially local routing messages are sent between
`devices along a chain of devices in whichever direction the
`message is sent, and thus although virtual circuits or con-
`nections are established between devices this is done
`dynamically, by means of local muting tables, rather than by
`some overall master. More particularly in embodiments a
`routing table entry for a device defines two connections, one
`for the link for the connection to the device, the second for
`the link for the connection from the device (for one-way
`communication only one of these links need be defined).
`Optionally the routing table may further include. for each
`link defined by a pair of channels for incoming and outgoing
`data, an identifier for the intended end recipient, although in
`
`Sonos Ex. 1004, p. 20
` Sonos v. Google
` IPR2021-00964
`
`

`

`US 2006/0120433 Al
`
`Jun. 8, 2006
`
`4
`
`embodiments this is not necessary because a message con-
`taining an identifier for the intended recipient is always
`forwarded (if it can be) unless the node is in fact the
`recipient.
`
`[0031] With embodiments of the above protocols the time
`to set up a virtual connection is relatively small compared
`with typical data transmission times and it is therefore
`practicable to tear down and replace virtual connections
`when necessary, for example when a connection is found to
`be broken because a node in a chain is no longer responding.
`A virtual connection may be removed, for example, by
`marking an entry in a local link table as available for reuse;
`alternatively an entry may be deleted. Such an amendment
`to a local link table may be made, for example, when a
`message cannot he forwarded because the recipient is not
`found or does not respond/acknowledge receipt. In such a
`case a disconne