Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 1 of 13
`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 1 of 13
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`EXHIBIT 3
`EXHIBIT 3
`
`
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`

`

`(12)
`
`United States Patent
`Vaisanen et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,560,443 B1
`May 6, 2003
`
`USOO6560443B1
`
`(54) ANTENNA SHARING SWITCHING
`CIRCUITRY FOR MULTI-TRANSCEIVER
`MOBILE TERMINAL AND METHOD
`THEREFOR
`
`(75) Inventors: Ari Vaisanen, Ruutana (FI); Pekko
`Orava, Tampere (FI)
`(73) Assignee: Nokia Corporation, Espoo (FI)
`(*) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/321,824
`(22) Filed:
`May 28, 1999
`(51) Int. Cl." .................................................. H04B 1/38
`(52) U.S. Cl. ................
`... 455/73; 455/82; 455/552
`(58) Field of Search ................................. 455/552,553,
`455/101, 103,73, 129, 277.1, 289, 550,
`78, 133, 82, 182; 375/220, 219
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`8/1988 Maile .......................... 455/82
`4,761,822 A
`1/1994 Kuisma
`5,276.920 A
`5,410,738 A 4/1995 Mud Rienk et al.
`5,420,599 A 5/1995 Erkocevic
`5,463,406 A * 10/1995 Vannatta et al. ............ 343/702
`5,507.035 A * 4/1996 Bantz et al. ................ 375/299
`5,550,554 A 8/1996 Erkocevic
`5,715,525 A
`2/1998 Tarusawa et al. ........... 455/101
`5,768,691 A 6/1998 Matero et al.
`5,794,159 A
`8/1998 Portin
`5,822,693 A * 10/1998 Harrison ..................... 455/432
`5,982,807 A * 11/1999 Snell .........
`... 370/342
`5,987.033 A * 11/1999 Boer et al.....
`... 370/313
`6,005,524. A * 12/1999 Hayes et al. ................ 343/702
`6,055.422 A * 4/2000 Saitoh ..........
`... 455/277.1
`6,138,010 A * 10/2000 Rabe et al. ................. 455/426
`6,326,926 B1 * 12/2001 Shoobridge et al. ........ 343/702
`2001/0012282 A1 * 8/2001 Yegoshin
`
`1/2002 Mattisson et al.
`2002/0012381 A1
`2002/0025778 A1 * 2/2002 Lee
`FOREIGN PATENT DOCUMENTS
`
`EP
`EP
`EP
`EP
`EP
`
`3/1992
`O 475 681 A2
`O 575 203 A1 12/1993
`O623967
`11/1994
`O 641 090 A2
`1/1995
`O866588
`9/1998
`
`OTHER PUBLICATIONS
`NEC Publication No. P12398EJ2V1DS00 (Second Edition),
`“L-Band SPDT Switch', Jan. 1998.
`* cited by examiner
`Primary Examiner-Charles N. Appiah
`(74) Attorney, Agent, or Firm-Antonelli, Terry, Stout &
`Kraus, LLP
`ABSTRACT
`(57)
`Antenna Switching circuitry in a multi-transceiver mobile
`terminal 10, which features a first switching unit (SW1)
`which controllably couples a first transceiver port (P) to
`either a first antenna port (PA) or a second antenna port
`(PA); and a second switching unit (SW2) which controlla
`bly couples the Second antenna port (PA) to either the first
`transceiver port (P), through the first Switching unit (SW1),
`or to an input/output port (P) of a second transceiver (12).
`According to this Scheme, the Second antenna port is
`coupled to the input/output port of the second transceiver
`(12) in a mode in which the second transceiver (12) is
`operational, the first transceiver port (P) being decoupled
`from the Second antenna port at this time, wherein the first
`transceiver port is coupled to the first antenna port and the
`input/output port of the Second transceiver (12) is decoupled
`from the Second antenna port, when the first transceiver is in
`a transmit mode, and wherein the first transceiver port is
`coupled to either of the first and Second antenna ports, when
`the first transceiver (11) is in a receiving mode and the
`input/output port of the Second transceiver (12) is decoupled
`from the Second antenna port.
`
`42 Claims, 4 Drawing Sheets
`
`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 2 of 13
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`
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`CONTROL
`CRCUIT
`
`

`

`U.S. Patent
`
`May 6, 2003
`
`Sheet 1 of 4
`
`US 6,560,443 B1
`
`
`
`ANT 2
`
`
`
`A/G 2
`
`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 3 of 13
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`CONTROL/28
`---------------------- CIRCUIT
`
`

`

`U.S. Patent
`
`May 6, 2003
`
`Sheet 2 of 4
`
`US 6,560,443 B1
`
`TR
`
`ANTSEL
`
`BTSEL
`
`TR
`
`SWBVC1
`
`SWBVC2
`
`SWCVC1
`
`SWCVC2
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`SWAVC1
`
`TRX - SWAVC2
`
`A/G 3A9
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`
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`SIGNAL FUNCTION
`ANTSEL SELECT ANT1 FANTSEL = 0 (ANTSELOVERRIDDEN WHEN TR-1
`BTSEL,
`BLUETOOTH ACTIVE IF BTSEL = 0
`RANSMITTERACTIVE IF TR 1
`TRX
`INVERSE OF TR
`
`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 4 of 13
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`VC1
`0
`0
`
`WC2
`0
`1
`1
`0
`
`ONNECTIONS
`PORTS 1, 2 AND 3 SOLATED
`ORT 1-PORT 3, PORT 2 SOLATED
`P
`PORT-PORT2, PORT 3 SOLATED
`P
`PORTS 1, 2 AND 3 SOLATED
`
`

`

`U.S. Patent
`
`May 6, 2003
`
`Sheet 3 of 4
`
`US 6,560,443 B1
`
`
`
`
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`ENWfToH CINQOH 9 SV 9N||O\/ CTTEIHS OITTWIEW
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`
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`07OWAS HOLINAS WNNELNW O || 9NICE|E|-
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`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 5 of 13
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`

`

`U.S. Patent
`
`May 6, 2003
`
`Sheet 4 of 4
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`US 6,560,443 B1
`
`
`
`HE/\HES
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`LES EO|/\HES
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`CECINE | XE
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`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 6 of 13
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`º 30/-/
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`NOIIVIS | |NOILVIS
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`SSE OOW,
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`|N|Od
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`SSE OO\fO|SV?
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`|N|Od|| || LES BOIAHES
`
`

`

`US 6,560,443 B1
`
`1
`ANTENNA SHARING SWITCHING
`CIRCUITRY FOR MULT-TRANSCEIVER
`MOBILE TERMINAL AND METHOD
`THEREFOR
`
`FIELD OF THE INVENTION
`This invention relates, generally, to the field of
`telecommunications/mobile terminals, Such as mobile
`phones and the like and, more particularly, it relates to an
`antennae sharing Scheme for diversity antennae in a dual
`radio hand-held terminal such as IP (Internet Protocol) based
`WLAN (Wireless Local Area Network)/BT (Bluetooth)
`hand-held terminal.
`
`15
`
`2
`communication by the ordinary citizen, as well as the Scope
`of wireless connectivity. Also, since BT is limited to short
`range communication, typically, under 10 meters, for
`example, 2-3 meters, it uses a considerably lower power
`level than that of WLAN. Namely, for a mobile phone, a
`WLAN DSSS radio operating in the 2.4 GHz ISM band
`having 30–50 meter range, for example, would typically
`require about 100 mW power level, whereas a BT ISM
`FHSS (Frequency Hopping Spread Spectrum) radio or,
`simply, a BT ISM spread spectrum radio would require
`about 1 mW power level. This technology enables portable
`electronic devices to connect and communicate wirelessly
`via short range, ad hoc networks.
`In order to function on a worldwide basis, Bluetooth
`requires a radio frequency that is license-free and open to
`any radio. The 2.4 GHz ISM band satisfies these
`requirements, the 2.4 GHz band actually being 2.4-2.483
`GHz radio band. When a Bluetooth radio is applied to a
`mobile phone, the user can leave the mobile phone clipped
`to his belt or in a pocket and walk around for the entire
`dial-up-connection. Also, because there are no line-of-Site
`requirements for Bluetooth devices, it is well Suited for
`wireleSS connectivity, Such as between a mobile phone and
`a notebook computer. For example, with Bluetooth, a perSon
`could synchronize their phone with a PC without taking the
`phone out of their pocket or briefcase. Users would be able
`to automatically receive E-mail on their notebook or laptop
`computers by the digital cellular phones in their pockets or
`synchronize their primary PC with their hand-held computer
`without taking it out of their briefcase. The omni-directional
`capability of Bluetooth allows synchronization to start when
`the phone is brought into range of the PC. It allows for a
`grOSS data rate of 1 Mbit/S, with Second generation plans to
`be increased to a ratio of 2 Mbit/second. It uses packets
`Switching protocol based on a frequency hopping Scheme
`(analogous to IEEE 802.11 standard). Also, because of its
`omnidirectionality, authentication and encryption is also
`included, for Security reasons, as part of the base band
`protocol thereof. That is, authentication relies on utilizing a
`Secret key (i.e., password or PIN), thereby assuring Security.
`In view of the attributes of this low power ISM radio band
`and its relevance to mobile terminals, Such as hand-held
`mobile (cellular) phones and the like, the present inventors
`have considered how to facilitate both the 2.4 GHz ISM
`band WLANDSSS radio and the low power/short range 2.4
`GHz ISM BT radio to effect a practical and cost-effective
`dual mode mobile terminal, namely, an IP based dual mode
`WLAN/BT hand-held terminal. Filter, antennae and RF
`switch components of a WLAN IEEE 802.11 DSSS radio
`and BT dual mode terminal can be shared in a number of
`ways, the inventors determined. In its simplest form, Such
`components are not shared, that is, both radioS are imple
`mented as Separate and independent units. However, this is
`obviously not the optimal Solution, both in terms of cost, as
`well as practicality. On the other hand, combining a low
`power short range 2.4 GHz ISM radio band device like a BT
`radio and a substantially higher power level WLAN device,
`like the 802.11 DSSS radio, into a small sized hand-held
`terminal, has Several drawbacks, namely, interference,
`resulting from Sharing of antennae, filters and other com
`ponents. In fact, Sharing a diversity antennae Scheme, filters
`and antennae Switches between two 2.4 GHz radios in a dual
`mode terminal has not been implemented earlier, as far as
`known. Therefore, Such problems had not existed in Such a
`form, earlier. Dual band mobile phones have somewhat
`Similar problems, but, however, as the two radioS in the dual
`band mobile phone employ different frequency bands, dif
`ferent approaches are used.
`
`BACKGROUND OF THE INVENTION
`Recently, a new technology has been developing which
`can expand the use of mobile phones in related hand-held
`mobile terminals using the same 2.4 GHz ISM (Industrial,
`Scientific and Medical) band as that employed by wireless
`LAN (WLAN) communication which conforms to the IEEE
`802.11 standard such as for DSSS (Direct Sequence Spread
`Spectrum) radio communication, the contents of which are
`incorporated herein by reference. This new technology is
`referred to as Bluetooth (BT) which is a low-powered radio
`technology, having a range of approximately 10 cm to 10 m,
`but can be extended for greater distances through simply
`increasing the transmit power level. The frequency band of
`this new technology calls for an ISM radio band at 2.4 GHz,
`which is a license-free spectrum band, practically, available
`worldwide and which conforms to the wireless LAN
`(WLAN) radio ISM band conforming to IEEE 802.11 stan
`dard for DSSS radio communication. Employment of this
`low power/lower range ISM band to mobile phone technol
`ogy would mean that cable hook-ups would no longer be
`required between laptop computers and cellular (or cell)
`phones to Send E-mail, as one example. Further, busineSS
`people would be able to Surf the internet on their laptop,
`while their mobile phone is in their jacket pocket. That is,
`the mobile phone, as one example of a mobile terminal, will
`no longer have to be limited to a basic service set (BSS) link,
`which typically consists of a number of Stations executing
`the same MAC (Medium Access Control) protocol in com
`peting for access to the same shared medium. (The basic
`45
`Service Set may be isolated or it may be connected to a
`backbone distribution System through an access point, the
`access point functioning as a bridge. The MAC protocol may
`be fully distributed or controlled by a central coordinated
`function housed in the access point. The basic Service Set
`generally corresponds to what is referred to as a cell in the
`literature. An extended service set (ESS) consists of two or
`more basic Service Sets interconnected by a distribution
`System. Such distribution System is, typically, a wired back
`bone LAN. The extended Service Set appears as a single
`logical LAN to the logical link control (LLC) level. FIG. 5
`of the drawings typifies a wireleSS LAN model conforming
`to the IEEE 802.11 standard.)
`In a WLAN link-up, a Single acceSS transceiver can
`Support a Small group of co-located users within a range of
`less than one hundred to Several hundred feet, typically. On
`the other hand, Bluetooth technology will enable users to
`connect their mobile computers, digital cellular phones,
`hand-held devices, network access points and other mobile
`devices by wireleSS Short-range radio links, unimpeded by
`line-of-Site restrictions using Substantially less power. Blue
`tooth (BT) technology will increase the ease of wireless
`
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`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 7 of 13
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`

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`US 6,560,443 B1
`
`15
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`3
`The present invention Specifically addresses the issue of
`antennae sharing between two 2.4 GHZ radioS in a dual
`mode terminal Such as would be effected in connection with
`an IP based dual mode WLAN/BT hand-held terminal. The
`present inventors are not aware of any earlier attempts at
`effecting antennae sharing in Such a dual mode terminal. On
`the other hand, the inventors are aware of Several earlier
`attempts at diversity antennae sharing, but, however, only
`with regard to a standard WLAN operation. One such known
`earlier scheme was disclosed by Lucent Technologies in EP
`0 623 967 A1, dated Nov. 9, 1994, which describes dual
`antennae diversity System for wireleSS LAN consisting of
`two L-shaped PIFA antennae. In that disclosure, a Single
`pole dual terminal switch (SPDT) is employed to effect
`Switching between the two antenna members in a receive
`mode and for Switching to only one of the two antenna
`members for operation of the apparatus in a transmit mode.
`However, that earlier disclosure did not address the issue of
`antenna Sharing of diversity antennae in a dual mode Scheme
`which calls for a common radio band Such as two 2.4 GHz
`radios, one being a WLAN radio conforming to the IEEE
`802.11 standard, referred to above, the contents of which are
`incorporated herein by reference, and the other being a
`relatively low power/low range radio, for example, a BT
`ISM FHSS radio.
`25
`A Slightly different antennae Switch and filter arrangement
`of a WLAN radio, with no detailed antennae description,
`was disclosed by Harris Corporation in EP 0 866 588 A2,
`dated Sep. 23, 1998. This published application also does
`not disclose anything about an antennae sharing Scheme of
`diversity antennae in a dual mode hand-held terminal as that
`to which the present invention addresses. However, the
`Harris disclosure does give an example of one wireless
`transceiver which may be readily used for WLAN applica
`tions in the 2.4 GHz ISM band according to the IEEE 802.11
`standard for DSSS radio communication. Use of two diver
`sity antennae, for example, PIFAS, in WLAN PC cards
`(previously known as PCMCIA card) is very popular
`because of multi-path propagation problems, while prior
`hand-held terminals operating on lower frequencies do not
`use diversity antennae.
`
`Case 1:19-cv-11586-FDS Document 265-3 Filed 01/04/22 Page 8 of 13
`
`OBJECTS OF THE INVENTION
`It is an object of this invention to realize an antennae
`Switching Scheme for Sharing diversity antennae efficiently
`and as economically as possible.
`It is also an object of this invention to effect a Substan
`tially interference-free Switching circuitry for Sharing a pair
`of diversity antennae in a multi-transceiver mobile terminal
`Such as a hand-held mobile terminal including, for example,
`mobile or cellular phones, although not limited thereto, in
`which both transceiverS operate, Substantially, on the same
`ISM radio band but having different power/range require
`mentS.
`It is a further object of invention to achieve a substantially
`interference-free antenna Sharing Scheme in the multi
`transceiver mobile terminal where one of the transceiverS is
`a WLAN radio and the other operates on Substantially the
`same ISM radio band.
`It is a still further object of this invention to achieve a
`Substantially interference-free antennae Sharing Scheme in
`connection with a hand-held mobile terminal having diver
`sity antennae for a dual mode mobile terminal having a
`WLAN radio operating on substantially a 2.4 GHz ISM band
`conforming to IEEE standard for DSSS radio communica
`tion and a relatively low power and short range spread
`
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`4
`Spectrum radio operating on a Substantially Same ISM radio
`band as that of the WLAN radio. In this connection, this
`Second lower power and shorter range radio can be one
`conforming to Bluetooth (BT) radio communication.
`It is an additional object to implement an antennae
`Switching Scheme for antennae Sharing of diversity antennae
`in the dual mode mobile terminal Scheme which is both
`economical and practical and which can be implemented
`without having to add an additional antenna for the Second
`transceiver.
`It is still a further object of this invention to achieve an
`antennae sharing Scheme in connection with a dual mode
`hand-held mobile terminal or hand-held terminal per se
`which can be implemented in a Standard mobile terminal
`such as a mobile (cellular) phone and the like, a PDA
`(personal digital assistant), as well as other wireless com
`munication links that can operate on an ISM radio band Such
`as the 2.4 GHz DSSS WLAN conforming to the IEEE
`802.11 standard, as one example (although not limited
`thereto).
`It is also an object of the present invention to overcome
`any inherent problem directed to antennae sharing, antennae
`Switching and pertaining to the filter chains associated with
`a WLAN/BT dual mode hand-held terminal, as one example,
`although not limited thereto. It is a still further to achieve an
`antennae Sharing Scheme which provides high performance
`in connection with the dual antennae receive mode of the
`diversity operation.
`It is also an object of the present invention to minimize the
`number of RF Switches and at the same time minimizing
`Switch losses for purposes of optimizing performance during
`operation of either one of the transceivers (radioS) in the
`mobile terminal.
`
`SUMMARY OF THE INVENTION
`The foregoing and other problems are overcome and the
`objects of the invention are realized through effecting anten
`nae Switching circuitry and antennae sharing method there
`for for a multi-transceiver mobile terminal in accordance
`with the examples illustrated in the related embodiments of
`this invention.
`In this connection the invention calls for a Switching
`Scheme for diversity antennae in a multi-transceiver mobile
`terminal where one such transceiver may be a WLAN
`conforming to the IEEE 802.11 standard for DSSS radio
`communication and the other may be a relatively lower
`power/lower range radio operating on the same ISM radio
`band as the WLAN such as conforming to Bluetooth radio,
`although not limited thereto. In accordance with this
`Scheme, the dual transceivers are not required to operate at
`the same time. The dropping of an antennae connection and
`the Setting up of a new antenna connection from Scratch, of
`course, takes time and requires electrical power. Therefore,
`one featured aspect of the invention permits the first
`transceiver, for example, the WLAN radio, to act as a
`receiver only, including, for example, to monitor when the
`AP (access point) directed thereto becomes available for
`communication while the Second transceiver is providing a
`needed connection, i.e., is operational. The present invention
`is achievable through using only the Standard diversity
`antennae of the WLAN network of the mobile terminal.
`According to a further aspect of the present invention,
`both the first and second transceivers, Such as the WLAN
`and BT radios, are able to receive RF signals at the same
`time Such as when the hand-held terminal is powered-up or
`in a situation where neither of the radioS are connected,
`
`

`

`15
`
`S
`although a connection may be needed. The versatility of the
`mobile phone effects integration (i.e., connectivity) between
`mobile computers, digital phones, network access points
`within a short range Scheme.
`Although there are Some minor drawbacks resulting from
`losses when Switching from the Second antenna, which is a
`diversity antenna shared between WLAN and Bluetooth, for
`example, the benefits arising as a result of using the low
`powered/low range Bluetooth radio, clearly, outweigh any
`Such drawbacks. In this connection, the present invention
`features a scheme in which one of the two WLAN diversity
`antennae is Switched for Bluetooth radio use when the
`Bluetooth radio needs to be functional. In general, the
`Second transceiver, for example, the Bluetooth radio, is
`connected to the antenna port assigned thereto when the
`mobile terminal is physically outside the coverage area of
`the WLAN radio. Since the WLAN radio would typically be
`the preferred choice of communication linkage, in a mobile
`terminal where one of the transceivers is a WLAN and the
`other is a BT radio, the WLAN coverage can be monitored
`during the time the Second transceiver, for example, the
`Bluetooth radio, is in use. During this time, the first trans
`ceiver is coupled at its receiver port to the first antenna
`monitoring an access point (AP), the access point becoming
`available through that one of the diversity antennae which is
`not being used by the Bluetooth radio.
`Also in accordance with the present invention, it becomes
`possible for the first transceiver, for example, the WLAN
`radio, to receive or monitor its frequency band without being
`destructively interfered with by the transmitted signal from
`the BT module, since the BT module requires, typically, one
`milliwatt or less power level. However, use of the WLAN
`transmitter while the BT radio is operational is prohibited as
`damages to the BT radio might occur.
`With regard to the question of diversity isolation during
`Simultaneous operation of the two antennae, this isolation
`could be improved with a metallic Structure connected as a
`Shield and located between the antennae. That is, according
`to one featured aspect of the invention, the mobile terminal
`includes a pair of diversity antennae which are separated
`with a metallic Structure, for example, a metallic plate
`attached to a ground plane and providing improved isolation
`to effect rf Shielding. According to one disclosed
`embodiment, although not limited thereto, the invention
`calls for each of the antennae to be a planar inverted F
`antenna (PIFA). The PIFAS can be rectangular (inclusive of
`both Square and oblong shaped rectangles) or even
`L-shaped, although not limited thereto. In this connection,
`the present invention has been Schemed to enable optimal
`Sharing of antennae and filter chains associated with the
`transceivers between that of the transmit and receive modes
`of two like ISM band radios Such as the 2.4 GHz. WLAN
`radio according to IEEE 802.11 standard for DSSS radio
`communication, and the 2.4 GHZ BT Spread spectrum radio,
`for dual mode mobile terminal implementation. The RF
`Switches employed are illustrated, for example, as Single
`pole double throw (SPDT) switches which are of well
`known variety which can be implemented in connection
`with a single RF chip or each can be associated with a
`Separate Semiconductor chip. In this connection, it is noted
`that both EPO 623 967 A1 and EPO 866 588 A2 disclose
`SPDTS; however, those SPDTs are employed for Switching
`between the receive and transmit modes of a WLAN radio
`(single transceiver). An example of an SPDT switch usable
`in the present invention is the NEC uPG/52TAL-band SPDT
`65
`(Single Pole Double Throw) GaAs FET switch which was
`developed for cellular or cordless telephone application and
`
`US 6,560,443 B1
`
`6
`is disclosed in NEC publication document No.
`P12398EJ2V1DS00 (second edition), dated January 1998,
`the contents of which are incorporated herein by reference.
`BRIEF DESCRIPTION OF THE DRAWINGS
`The above set forth and other featured aspects of the
`invention are made more apparent in the ensuing detailed
`description of the invention when read in conjunction with
`the related examples described and illustrated in the accom
`panying drawings, wherein:
`FIG. 1 is a Schematic diagram illustrating the principle of
`the antenna Sharing Switching arrangement according to one
`embodiment of the present invention;
`FIG. 2 is a diagram illustrating the antenna Sharing
`Switching arrangement according to another representative
`embodiment of the present invention;
`FIG. 3A illustrates an example of a logic circuit diagram
`relating to the control circuit according to FIG. 2;
`FIG. 3B is illustrative of an example of signal descriptions
`asSociated with the antenna Switch control logic arrange
`ment in FIG. 3A;
`FIG. 3C is illustrative of an example of the antennae
`Switch truth table as it relates to the embodiment in FIG. 2
`of the drawings,
`FIG. 4 illustrates an antenna System consisting of two
`high efficiency PIFA-type rectangular antennae, which are
`uSeable in the antenna Sharing Scheme of the present
`invention, according to one example, and
`FIG. 5 represents a WLAN standard developed by the
`IEEE 802.11 committee.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`FIG. 1 illustrates the principle of the present invention in
`accordance with a first embodiment of the present invention
`in which 10 represents as mobile terminal such as a mobile
`(cellular) phone having a dual antenna, dual transceiver
`arrangement which can be, for example, an IP-based
`WLAN/Bluetooth hand-held terminal. The basic idea is to
`Switch one of the two WLAN diversity antennae ANT1 and
`ANT2 for BT (Bluetooth) use, when BT needs to be func
`tional. In general, BT connection is effected when the
`hand-held terminal is located outside the available coverage
`of WLAN. As the WLAN radio communication is the
`preferred method, WLAN coverage of an AP (access point)
`can be constantly monitored, while the BT radio (BT
`module) 12 is in use. Simultaneous operation is limited to
`the receive (rx) mode of the WLAN radio (WLAN module)
`11 when the BT radio (BT module) 12 is operational, either
`in the receive (rx) or the transmit (tx) mode, in order to
`protect the BT transceiver from permanent damage.
`Specifically, the antennae Switching circuitry 13 in the
`multi-transceiver mobile terminal 10 has a first Switching
`unit SW1 which controllably couples the first transceiver
`port P to either a first antenna port PA or a Second antenna
`port PA, and has a Second Switching unit, namely, SPDT
`Switch SW2, which couples the Second antenna port PA to
`either the first transceiver port P, through the first Switching
`unit SW1, or to an input/output port P.
`of a second
`transceiver 12 which is, in this example, a BT radio having,
`substantially, a same ISM radio band as that of the WLAN
`module 11, such as, for example, a 2.4 GHz ISM band
`WLAN radio according to IEEE 802.11 standard for DSSS
`radio. In accordance with this embodiment, the SPDT
`Switches SW1 and SW2 are controlled by the control circuit
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`US 6,560,443 B1
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`14 in a manner in which the Second antennae port PA is
`coupled to the input/output port of the Second transceiver 12
`in a mode in which the Second transceiver 12 is operational,
`at which time, also, the first transceiver port PA is
`decoupled from the Second antenna port PA. Also, the first
`transceiver port P is coupled to the first antenna port PA
`and the input/output port of the Second transceiver 12 is
`decoupled from the Second antennae port PA, when the first
`transceiver port is in the transmit mode, and, further, the first
`transceiver port P is coupled to either of the first and Second
`antennae ports, when the first transceiver is in a receiving
`mode and the input/output port Pro of the Second transceiver
`12 is decoupled from the Second antenna port PA. Also,
`according to this Scheme, when the Second transceiver 12 is
`operational, the Second antennae port PA is coupled to the
`input/output port of the Second transceiver 12 and the first
`transceiver 11 is decoupled from the Second antenna port PA
`and is coupled to the first antenna port PA as a receiver only.
`Simultaneous operation, however, is limited to, for example,
`WLAN rx with BT on rx or tx only. The second transceiver,
`for example, the BT module, cannot operate if the first
`transceiver, for example, the WLAN module, is transmitting.
`This new Scheme, according to the example illustrated in
`FIG. 1, provides for the implementation of an additional
`transceiver, such as the BT module 12, with the already
`existing first receiver, for example, a WLAN radio, in a
`Standard size mobile terminal, without adding an additional
`antenna for the newly added BT module. Since an antennae
`diversity scheme would be preferable in connection with a
`2.4 GHz ISM band WLAN device like IEEE 802.11 stan
`dard for DSSS radio communication to overcome multi-path
`propagation, using one of the two separate diversity anten
`nae for occasional BT use Saves the cost and Space of adding
`yet another antennae to a Standard size hand-held mobile
`terminal unit.
`FIG. 2 is illustrative of another embodiment which shows
`an antennae sharing Switching arrangement for a multi
`transceiver mobile terminal Such as, although not limited
`thereto, an IP based dual mode WLAN/BT hand-held ter
`minal. In accordance with this example illustration of the
`present invention, 21 represents the first transceiver, for
`example, 2.4 GHz ISM band WLAN module or device
`according to the IEEE 802.11 standard for DSSS radio
`communication and 22 represents the added Second trans
`ceiver which is illustrated in this example, although not
`limited thereto, to a BT module.
`In the embodiment of FIG. 2, in the WLAN transmit
`mode, or the first mode, the third SPDT Switch Swc is
`Switched to the position 2 where it connects a Second
`antenna port PA to the Second Switch Sw8. In this mode,
`also, the first Switching unit SWA is Switched from position
`3 to position 2 thereof to thereby form a connection to the
`output port P of the WLAN module. Under this WLAN
`transmit mode, only antenna ANT1 is used as the WLAN
`transmit antenna. The Second Switching unit Sw8 is
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`Switched to the position where it connects the WLAN
`receive chain at the input port P to the unconnected port 3
`of Switch SwA so as to prevent the WLAN transmit signal
`which is coupled from the first antenna ANT1 to the second
`antenna ANT2 from leaking into the WLAN receive chain.
`Filter FL2 in the WLAN transmit chain can be optimally
`chosen therefor for best performance Since it does not have
`to be shared with the WLAN receive chain under this
`operation mode.
`According to a Second mode, namely, the BT mode, the
`third switching unit SwC is Switched to a position 3 where
`it connects the BT module to the Second antenna port P.A.
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`In this BT mode, the second switching unit SwB Switches to
`the position 3 where the WLAN receive chain, including
`filter FL1 is connected to the first Switching unit SwA in
`order to minimize leakage of the BT transmit Signal into the
`receiver port of the WLAN module. In this BT mode, the
`WLAN coverage can be monitored by Switching SwA to a
`position 3 where it connects the first antenna port to the
`WLAN receiver chain via second Switching unit SwB.
`In accordance with a third mode, namely, the WLAN
`receive mode, the third switching unit SwC is switched to a
`position where the Second antenna port PA is coupled to
`Switch SwB. Also, first Switching unit SwA is switched to a
`position where it connects the first antenna port PA to
`Switch SwB. Through turning of the second Switching unit
`SwB antenna, diversity selection can be made between the
`first and second antennae ports. Filter FL1 in the WLAN
`receive chain can be optimally chosen for best performance
`as it does not have to be shared with the WLAN transmit
`chain.
`The operation of the example in FIG. 2, of another
`embodiment according to the present invention, can be
`clearly understood in connection with the Signal description
`and the Switch truth table Schemes shown in FIGS. 3B and
`3C of the drawings, respectively, in conjunction with the
`antennae Switch logic operation effected by the logic cir
`cuitry shown in FIG. 3A of the drawings as it relates to the
`control circuit 23 in FIG. 2 thereof. In this connection, when
`the logic values of VC1 and VC2 as they relate to each of
`the three Switching units, are at logic 0, all three ports of the
`SPDT switches are isolated. This is simila