This patent issued on a continued pros-
`ecution application ?led under 37 CFR
`ABSTRACT
`(57)
`1.53(d), and is subject to the tWenty year
`ligtznt germ provlslons of 35 USC’ A transceiver Which keeps circuitry associated With a
`(a)(
`receiver in a poWered doWn state during periods When a
`Subject to any disclaimer the term of this
`R'eceived'Signal Strength Indicator (RSSI) indicates that a
`patent is extended or adgusted under 35
`signal being received is beloW a pre-deterrnined threshold
`U‘SC' 154(k)) by 0 days‘
`level, and Which begins to poWer up the transmitter as soon
`as it is determined that a packet being received requires a
`response. The RSSI signal represents the strength of any
`signal current being received, and if the RSSI signal falls
`beloW a given threshold level, digital circuitry associated
`With the back-end circuitry of the receiver system is dis
`abled. If the RSSI signal rises above the threshold level, the
`digital circuitry of the receiver is enabled. A control circuit
`Within the transceiver processes the packet as it is received
`to determine Whether the packet requires a response. If it is
`determined that a response is necessary’ the Control Circuit
`provides a control signal to the transmitter to povver up the
`transmit“ from a Sleep mode even before the en?“ Packet
`has been received and processed. The control circuit then
`continues to~process the remainder of the packet as it is
`received While the transmitter poWers up from the sleep
`mode. In this manner, the transmitter will become stabilized
`much earlier. Accordingly, the transceiver is able to respond
`more quickly than conventional devices and is thus able to
`increase response times and overall data exchange rates.
`Moreover, battery poWer of the transceiver is utilized more
`ef?fneq?y compar‘gfd to devlces whlch must Connnuously
`maintain the receiver and transmitter in fully poWered
`modes~
`
`Continuation-in-part of application No. 08/605,914, ?led on
`Feb- 23, 1996, HOW Pat- NO- 5,838,729
`Int. Cl.7 ............................. .. H04B 1/38; H04B 1/16;
`H04B 7/00; H04L 5/16
`US. Cl. ........................ .. 375/219 375/220 375/222
`455/383 455/73_ 4556111 455/343’_ 45557,;
`Field of Search
`’
`’
`375/220 219
`73 31 1’ 38 3’
`’
`'
`’
`'
`
`’
`
`’
`’
`References Cited
`
`(12) United States Patent
`Morelli et al.
`
`US006236674B1
`US 6,236,674 B1
`*May 22, 2001
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`TRANSCEIVER CONTROL WITH SLEEP
`MODE OPERATION
`
`Inventors: Daniel J. Morelli, Norton; Michael L.
`Trompower, Navarre, both of OH (US)
`
`Assignee: Teletransactions, IIlC., AkI‘OIl, OH (US)
`
`Notice:
`
`5,029,183
`5,103,461
`5,142,550
`
`7/1991 Tymes .
`4/1992 Tymes .
`8/1992 Tymes.
`-
`-
`(Llst Connnued on next page‘)
`Primary Examiner—Stephen Chin
`Assistant Examiner—Michae1 W_ Maddox
`(74) Attorney, Agent, or Firm—Renner, Otto, Boisselle &
`Sklar, L_L_P_
`
`Appl' NO‘: 08/619’797
`Filed;
`Man 20, 1996
`
`Rehted U_S_ App?cation Data
`
`(54)
`
`(75)
`
`(73)
`(*)
`
`(21)
`(22)
`
`(63)
`
`(51)
`
`(52)
`
`(58)
`
`(56)
`
`US. PATENT DOCUMENTS
`4 194 153 * 3/1980 Masaki et al
`4384361 * 5/1983 Masaki .....
`4:577:315
`3/1986 Otsuka '
`4,903,319 * 2/1990 Kasai et al. .......................... .. 455/33
`4,955,038
`9/1990 Lee et al. .
`5,027,428 * 6/1991 Ishiguro et a1. ..................... .. 455/67
`
`340/825 44
`................... .. 455/31
`
`43 Claims, 11 Drawing Sheets
`
`26
`
`BATT
`
`30 \
`MAC
`A A
`
`101'
`
`/ 12
`
`f 32
`
`> TX
`
`/ 22
`
`14
`
`M K
`
`38
`/
`
`/' 36
`
`TX‘
`\0
`: ‘TE
`RCV \_ 20
`
`RSSI
`
`16
`/ 39 f
`
`f 24
`
`34 j
`
`V RCV ‘
`
`Dish
`Exhibit 1005, Page 1
`
`

`
`US 6,236,674 B1
`Page 2
`
`US. PATENT DOCUMENTS
`
`5,144,296 * 9/1992 DeLuca et a1. ............... .. 340/825.44
`5,157,687
`10/1992 Tymes-
`
`5,471,655 * 11/1995 Kivari ................................ .. 455/127
`5,479,441
`12/1995 Tymes et a1. .
`5519506
`5/1996 D’Avello et aL _
`5,524,021
`6/1996 8660611 6161..
`
`5,179,724 * 1/1993 Llndoff ................................. .. 455/76
`
`5541976 * 7/1996 Ghisler _ _ _ _ _
`
`_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ u 379/57
`
`6/1993 Tuch eta1~~
`5,220,564
`5,265,270 * 11/1993 Stengel et a1. ..................... .. 455/343
`5,276,680
`1/1994 Messenger-
`5,280,498
`1/1994 Tymes er 91--
`5,392,023 * 2/1995 D’Avello e161. .................. .. 358/400
`5,440,298 * 8/1995 Kuramatsu ........................ .. 455/383
`
`370/953
`5,559,804 * 9/1996 Amada eta
`455/343
`5566366 * 10/1996 Russo et a1
`455/383
`5,606,728 * 2/1997 Keba e161. ..
`5,734,686 * 3/1998 Kuramatsu .................... .. 340/82544
`
`* cited by examiner
`
`Dish
`Exhibit 1005, Page 2
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 1 0f 11
`
`US 6,236,674 B1
`
`14
`
`26
`
`AT
`B T
`
`30
`\
`MAC
`
`A A
`
`10 1'
`
`32
`f
`
`f 12
`> TX
`
`22
`/
`
`A
`K 28
`
`f 38
`
`36 f
`
`TX"
`U
`> 7%
`RCV \ 2o
`
`RSSI
`
`16
`/ 39 f
`
`f 24
`
`34 /
`
`V RCV ‘
`
`Hg. 1
`
`1L
`
`TYPE/
`SYNC HEADER LENGTH ADDRESS
`|
`
`DATA
`
`CRC
`
`Fig. 2
`
`Dish
`Exhibit 1005, Page 3
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`11f02LI.66hS
`
`US 6,236,674 B1
`
`100 V.LVCl
`
`mmzmw/mm__mm<ooz_s_:.S
`
`::om_o
`
`G'El|:| HJ.9N3'|
`
`o._o:wmm_¢
`
`mm._w_wmm
`
`._<._._O_D
`
`mo+<m<n_s_oo
`
`m_ok<m<n_s_oo
`
`o_mo._‘ozaoomomop<_>__omoE9.6A>—no8S«NELJam
`
`.>om
`
`mm3
`
`
`
`9%.s_oE8
`
`wm_._._oEzoox»
`
`
`
`oz_o_>_ov_OO._Oon
`
`
`
`good_2m:w>w8o<_>_s_oE~nI2
`::om_o«N
`
`5
`
`Dish
`Exhibit 1005, Page 4
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 3 6f 11
`
`US 6,236,674 B1
`
`INITIALIZATIONI
`THRESHOLD = —80 dbm
`
`/ 93a
`
`/ 93b
`
`DELAY = 5 seconds
`
`CHANNEL
`CLEAR?
`
`YES /- 93d
`
`SAMPLE AND
`STORE RSSI
`
`93f
`
`/ 94
`
`DELAY 50 ms
`
`ARE
`THERE 4 RSSI
`SAMPLES
`?
`
`YES / 95
`
`FIND RSSI
`AVERAGE
`
`/96
`
`‘
`SET
`THRESHOLD AT
`AVERAGE RSSI +
`10dbm
`
`Dish
`Exhibit 1005, Page 5
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 4 0f 11
`
`US 6,236,674 B1
`
`START
`
`973‘
`
`4
`w
`
`97b
`
`"
`IS
`RSSI >
`THRESHOLD
`?
`
`RCV ——> ACTIVE
`
`97d
`
`IS
`CARRIER
`SENSE >
`THRESHOLD
`?
`
`/' 976
`
`YES
`
`RCV —> ACTIVE
`
`V
`
`LEVEL 1
`
`LEVEL 2
`
`LEVEL 3
`
`LENGTH FIELD
`ASCERTAINABLE
`
`/ 97h
`
`RCV—> ACTIVE
`FOR AT LEAST
`TIME TO
`RECEIVE PACKET
`
`RCV——> SLEEP
`
`Dish
`Exhibit 1005, Page 6
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 5 6f 11
`
`US 6,236,674 B1
`
`RECEIVE
`HEADER OF
`EW PACKET?
`
`YES /— 104
`
`GET PACKET LENGTH,
`TYPE AND ADDRESS
`
`/—110
`PROCESS
`PACKET
`
`PACKET DIRECTED TO
`RECEIVING DEVICE
`
`ACKET TYP
`THAT NEEDS TO BE
`RESPONDED
`
`112
`TURN ON TX FROM
`SLEEP TO ACTIVE
`
`V
`
`114
`
`RECEIVE PACKET DATA
`
`1
`CHECK PACKET ERROR
`CORRECTING CODE
`
`116
`
`A NEGATIVE
`ACKNOWLEDGEMENT
`REQUIRED
`
`ERROR IN THE
`RECEIVED
`PACKET
`?
`
`N04
`
`Dish
`Exhibit 1005, Page 7
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 6 6f 11
`
`US 6,236,674 B1
`
`/_122
`
`SWITCH ANTENNA
`TO TX AT END
`OF RECEIVED PACKET
`
`/_124
`
`TRANSMIT RESPONSE PACKET
`AFTER ENTIRE PACKET HAS
`BEEN RECEIVED AND AT LEAST
`AFTER TIME TSA FOLLOWING
`RECEIPT OF PACKET
`TYPE FIELD
`
`/-—126
`
`TURN OFF TX
`&
`SWITCH ANTENNA
`BACK TO RCV
`
`Fig. 6B
`
`Dish
`Exhibit 1005, Page 8
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 7 0f 11
`
`US 6,236,674 B1
`
`A“
`
`010
`
`_______.____.________,_..________.
`
`/ F
`
`omo
`
`
`
`/: cm
`
`Em:
`
`_
`
`- X._.
`
`mwmmoo<
`IBZHYMEEI
`wwwoomm w m>_momm
`
`/ we.
`
`Eva/E
`
`Dish
`Exhibit 1005, Page 9
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 8 0f 11
`
`US 6,236,674 B1
`
`110 /
`PROCESS
`132 x PACKET
`
`RECEIVE
`HEADER OF
`NEW PACKET
`
`SCHEDULE DELAY
`TDEL = REMAINING PACKET
`LENGTH ' TSA BEFORE
`TURNING ON TX FROM SLEEP
`TO ACTIVE
`
`NO
`
`REMAINING
`PACKET LENGTH
`>TSA
`?
`
`104
`
`106
`
`GET PACKET LENGTH’
`TYPE AND ADDRESS
`
`IS
`PACKET DIRECTED
`TO RECEIVING
`DEVICE ?
`
`130
`
`YES
`
`PACKET TYPE
`THAT NEEDS TO BE
`RESPONDED TO
`
`TURN
`OFF TX
`
`121 J
`
`112
`1
`TURN ON TX FROM
`SLEEP TO ACTIVE
`
`114
`
`q
`RECEIVE
`PACKET DATA
`
`116
`
`CHECK PACKET
`ERROR
`CORRECTING CODE
`I_____
`
`RECEIVED
`PACKET
`
`4
`
`120
`
`A NEGATIVE
`ACKNOWLEDGEMENT
`REQUIRED
`
`Fig. 8A
`
`Dish
`Exhibit 1005, Page 10
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 9 0f 11
`
`US 6,236,674 B1
`
`/—~ 122
`
`SWITCH ANTENNA
`TO TX AT END
`OF RECEIVED PACKET
`
`/— 124'
`
`TRANSMIT RESPONSE PACKET
`BEGINNING AT END OF RECEIVED
`PACKET
`
`/--126
`
`TURN OFF TX
`&
`SWITCH ANTENNA
`BACK TO RCV
`
`Fig. 8B
`
`Dish
`Exhibit 1005, Page 11
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 10 0f 11
`
`US 6,236,674 B1
`
`_.| Pl 3
`
`62682 4/
`
`XP
`
`Dish
`Exhibit 1005, Page 12
`
`

`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 11 0f 11
`
`US 6,236,674 B1
`
`2 .9".
`
`NON ./
`
`3N ) 556200
`50:
`
`wow 1/
`
`IL
`
`wow /
`
`>Om
`
`IL
`
`orm/
`
`D
`
`ovu/
`
`1
`
`ooN
`
`Dish
`Exhibit 1005, Page 13
`
`

`
`US 6,236,674 B1
`
`1
`TRANSCEIVER CONTROL WITH SLEEP
`MODE OPERATION
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`This application is a continuation-in-part of US. patent
`application Ser. No. 08/605,914, ?led on Feb. 23, 1996 now
`US. Pat. No. 5,838,720.
`
`TECHNICAL FIELD
`The present invention relates generally to Wireless com
`munication devices, and more particularly to transceivers
`having a receiver and/or transmitter Which sWitches betWeen
`a high poWer consumption mode and a loW poWer consump
`tion (or “sleep”) mode.
`BACKGROUND OF THE INVENTION
`In recent years, the use of Wireless communication sys
`tems having mobile transceivers Which communicate With a
`hardwired netWork, such as a local area netWork (LAN) or
`a Wide area netWork (WAN), has become Widespread. The
`mobile transceivers, commonly referred to as mobile
`terminals, may take one of several different forms. For
`instance, in retail stores hand-held scanning units may be
`used to alloW for scanning inventory bar codes. In a
`Warehouse, portable units mounted to a vehicle may be used
`to gather information from the Warehouse ?oor. In a medical
`environment, the mobile terminal may take the form of a pen
`based Workslate Which alloWs medical personnel to Work
`With full page screens at once.
`In a typical Wireless communication system, each mobile
`terminal communicates With a netWorked system via a radio
`or optical link in order to alloW for a real time exchange of
`information. The mobile terminals communicate through
`one of several base stations interconnected to the netWork.
`The base stations alloW for a Wireless data communication
`path to be formed.
`Each mobile terminal and base station communicate via
`their respective transmitter and receiver (i.e., transceiver)
`systems. Typically, the transmitter and receiver in each
`device share the same antenna and a control signal is used
`to sWitch the antenna betWeen a transmitting and receiving
`mode. Thus, only one of the transmitter or receiver needs to
`be active at any given time.
`Information exchanged betWeen mobile terminals and
`base stations is generally sent in packet format. Packets of
`information (also referred to herein simply as “packets” or
`“data packets”) are a de?ned set of data bits Which carry
`information such as source address, destination address,
`synchroniZation bits, data, error correcting codes, etc.
`In order to provide for an ef?cient operating system,
`access to a channel is expeditiously controlled by a media
`access protocol. For example, a typical media access pro
`tocol may provide that if a device receives a packet Which
`requires a response, transmission of the response must be
`initiated Within a time period on the order of 15 micro
`seconds after receiving the entire original packet. This time
`span, or slot time, is referred to as the short inter-frame space
`(SIFS). The purpose of the SIFS is tWofold. First, it speeds
`up data exchange betWeen devices by limiting the amount of
`time a device can take to respond. Secondly, it limits the
`amount of time a device receiving the response must remain
`in the receiving mode. As mentioned above, since the
`transmitter and receiver oftentimes are connected to the
`same antenna, a device may miss information if it is trans
`mitting information at the same time it could be receiving
`information.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`During such time When a device is receiving information
`but not transmitting information, a fully poWered transmitter
`can nevertheless consume a considerable amount of poWer.
`In order to conserve poWer in the above mentioned mobile
`terminals, for example, the transmitter and perhaps other
`non-essential circuitry is generally placed into a sleep-like
`state, referred to herein as a “sleep mode”, during periods
`Where the system is receiving information. During the sleep
`mode, the poWer provided to the transmitter and other
`non-essential circuitry is reduced to minimum levels. Since
`most mobile terminals operate on battery poWer, the sleep
`mode helps maintain a longer usable battery life Without the
`need for recharging or replacing the battery.
`An unfortunate consequence of placing the transmitter of
`a device into a sleep mode is that the data exchange rate Will
`be reduced. The reduction in data exchange rate is attribut
`able to the time required for the transmitter to stabiliZe into
`a fully poWered or active state after a signal is sent to the
`transmitter indicating that it needs to transmit information.
`For instance, it is common for transmitter circuitry to take
`approximately tWo-thirds of the alloWed SIFS time to sta
`biliZe. During such time, information is neither being trans
`mitted or received by the responding device. As a
`consequence, overall data exchange rate suffers.
`Furthermore, given the strict SIFS time limitations typically
`in place, it is dif?cult for the transmitter to respond to a
`packet during the short period of SIFS time remaining after
`the transmitter has reached a fully poWered state (i.e.,
`stabiliZed). Systems attempting to meet the aforementioned
`strict SIFS time limitations typically have higher probabili
`ties of errors occurring in each transmission. In addition, as
`higher spectral density modulation techniques are imple
`mented (typically to increase data rate), more complex
`transmitter circuitry is utiliZed Which requires even longer
`stabiliZation time. Thus, even greater possibilities of trans
`mission errors or sloWer data exchange rates exist.
`It is also knoWn in the art to conserve poWer Within a
`device by reducing the poWer provided to the receiver When
`a device is transmitting information. According to one
`conventional approach, a transceiver in a mobile terminal
`poWers up its receiver only at predetermined times or
`intervals during Which the device may receive information.
`For the remainder of the time, the receiver circuitry remains
`in a poWered doWn state, i.e., a sleep mode. For example,
`according to one conventional protocol, during the times the
`receiver of the mobile terminal is poWered up, the mobile
`terminal listens for “beacons” sent from base stations indi
`cating there is information Which needs to be transmitted to
`the mobile terminal. If information Within a beacon indicates
`that a base station has information stored therein to be
`transmitted to the mobile terminal, the mobile terminal in
`turn transmits a “poll” packet requesting that the information
`be sent. By using this protocol, the mobile terminal can keep
`its receiver in a sleep mode at all times except When it is
`active to listen for a beacon and for a short time after the
`mobile terminal sends a poll packet and is therefore poised
`to receive information buffered in the base station. Thus,
`poWer may be conserved.
`Unfortunately, hoWever, regardless of When a base station
`is prepared to communicate With the mobile terminal, the
`base station must buffer all information until such time When
`the mobile terminal indicates to the base station that its
`receiver is activated from the sleep mode to receive infor
`mation. The undesirable result of this poWer saving protocol
`is that, in exchange for the poWer conservation obtained via
`this mode, a substantial reduction in the data exchange rate
`results. More speci?cally, since the mobile terminal receiver
`
`Dish
`Exhibit 1005, Page 14
`
`

`
`US 6,236,674 B1
`
`3
`cannot receive information at all times there is a delay in the
`exchange of data.
`Other conventional approaches for conserving poWer by
`placing the receiver into a sleeping mode suffer from similar
`drawbacks. For example, according to another technique the
`mobile terminal and base station are con?gured in a master
`slave relationship. The mobile terminal is designated master
`and poWers up its receiver from a sleep mode only during
`such times as the mobile terminal expects/desires to receive
`information. Again, hoWever, the mobile terminal cannot
`receive information at all times. As a result, the data
`exchange rate is much loWer than in the case Where the
`mobile terminal is able to receive information at virtually
`any time.
`In vieW of the aforementioned shortcomings in existing
`transceivers due to the combination of the necessity to
`conserve poWer, the time limitations for responding to an
`information packet, and the desire for higher data rates, there
`is a strong need in the art for a transceiver Which overcomes
`such draWbacks. More speci?cally, there is a strong need in
`the art for a transceiver in Which the sWitching of the
`transmitter betWeen an active mode and a sleep mode alloWs
`for suf?cient time to respond to packets Within a prescribed
`response period, even at high data rates in Which the system
`may be operating. Furthermore, there is a strong need for a
`transceiver having a receiver Which can receive data packets
`at any time While still utiliZing a loW poWer consumption
`mode of operation. More generally, there is a strong need in
`the art for a transceiver and system Which can maintain an
`optimal data exchange rate While continuing to conserve
`poWer by operating in a poWer savings mode of operation.
`
`SUMMARY OF THE INVENTION
`
`The present invention relates to a transceiver in Which the
`transmitter and/or receiver is sWitched betWeen an active
`mode and a sleep mode in order to conserve poWer Without
`substantially sacri?cing data exchange rates. According to
`the preferred embodiment, the present invention utiliZes an
`existing receive-signal-strength-indicator (RSSI) signal and/
`or one or more properties of an incoming signal to control
`poWer provided to portions of the circuitry in the receiver to
`sWitch the receiver betWeen an active mode and a sleep
`mode. As an example, the RSSI signal represents the signal
`strength of any signal Which is received by the front end of
`the transceiver. If the strength of the RSSI signal falls beloW
`a given threshold level, poWer provided to nonessential
`portions of the circuitry Within the receiver is reduced to
`place the receiver in a sleep mode. While in a sleep mode,
`the receiver continues to monitor the RSSI signal. If the
`RSSI signal goes above the threshold level, thus indicating
`an incoming signal, poWer is again applied to portions of
`circuitry Within the receiver to sWitch the receiver back to an
`active mode. Since the portion of the receiver circuitry
`Which is poWered doWn during the sleep mode is digital
`circuitry Which may be stabiliZed almost instantaneously,
`the receiver quickly sWitches from the sleep mode to the
`active mode. Consequently, receipt and processing of the
`received signal may be initiated essentially immediately.
`Such control of the poWer applied to the receiver circuitry
`based on the RSSI signal or other properties of the incoming
`signal provides tWo distinct bene?ts. First, conservation of
`poWer is achieved by requiring that the receiver circuitry be
`fully poWered only When a signal of suf?cient strength
`and/or intelligibility is received. Secondly, system perfor
`mance is optimiZed With respect to data exchange rates as a
`result of the mobile terminal receiver alWays being able to
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`4
`change quickly from a sleep mode to an active mode to
`receive information. Consequently, no delays in the
`exchange of information exist as compared to mobile ter
`minals operating in a conventional poWer savings mode.
`Additionally, the present invention relates speci?cally to
`a transceiver Which begins to poWer up the transmitter as
`soon as it is determined that a packet being received requires
`a response. Acontrol circuit Within the transceiver processes
`the packet as it is received to determine Whether the packet
`requires a response. If it is determined that a response is
`necessary, the control circuit provides a control signal to the
`transmitter to poWer up the transmitter from a sleep mode
`even before the entire packet has been received. The control
`circuit then continues to process the remainder of the packet
`as it is received While the transmitter poWers up from the
`sleep mode. In this manner, the transmitter Will become
`stabiliZed much earlier. Accordingly, the transceiver is able
`to respond more quickly than conventional devices and is
`thus able to increase response times and overall data
`exchange rates. Moreover, battery poWer of the transceiver
`is utiliZed more ef?ciently as compared to devices Which
`must continuously maintain the transmitter in a fully poW
`ered mode.
`According to one aspect of the invention, a transceiver
`apparatus is provided, including: a transmitter portion for
`transmitting information; a receiver portion for receiving
`information, the receiver portion being sWitchable betWeen
`a loW poWer consumption mode and an active mode; and a
`control circuit coupled to the receiver portion for selectively
`sWitching the receiver portion from the loW poWer consump
`tion mode to the active mode upon detecting an information
`signal to be received by the receiver, Whereby the receiver
`portion receives the information signal in the active mode.
`According to another aspect of the invention, a trans
`ceiver apparatus is provided, including: a transmitter portion
`for transmitting information; and a receiver portion for
`receiving information, Wherein the receiver portion includes
`circuitry for detecting a signal strength of a received signal,
`and circuitry for disabling receiver circuitry included in the
`receiver portion if the signal strength of the received signal
`is beloW a pre-determined threshold.
`In accordance With yet another aspect of the invention, a
`method for controlling a transceiver apparatus having a
`transmitter portion for transmitting information; and a
`receiver portion for receiving information, the receiver por
`tion being sWitchable betWeen a loW poWer consumption
`mode and an active mode is provided, the method including
`the step of: selectively sWitching the receiver portion from
`the loW poWer consumption mode to the active mode upon
`detecting an information signal to be received by the
`receiver, Whereby the receiver portion receives the informa
`tion signal in the active mode.
`According to a further aspect of the invention, a method
`for controlling a transceiver apparatus having transmitter
`portion for transmitting information; and a receiver portion
`for receiving information, the receiver portion being sWit
`chable betWeen a loW poWer consumption mode and an
`active mode is provided, the method including the step of:
`selectively sWitching the receiver portion from the active
`mode to the loW poWer consumption mode if a signal
`strength of a received signal falls beloW a predetermined
`threshold.
`In yet another aspect of the invention, a transceiver
`apparatus is provided, including: a transmitter portion for
`transmitting information, the transmitter portion being
`sWitchable, based on a control input, betWeen a loW poWer
`
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`Exhibit 1005, Page 15
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`US 6,236,674 B1
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`5
`consumption mode and an active mode during Which infor
`mation is transmitted; a receiver portion for receiving
`information, the receiver portion being switchable betWeen
`a loW poWer consumption mode and an active mode; and a
`control circuit coupled to the receiver portion for selectively
`sWitching the receiver portion from the loW poWer consump
`tion mode to the active mode by detecting an information
`signal to be received by the receiver, Whereby the receiver
`portion receives the information signal in the active mode.
`In accordance With still another aspect of the invention, a
`receiver apparatus is provided, including: a receiver portion
`for receiving information, Wherein the receiver portion
`includes circuitry for detecting a signal strength of a
`received signal, and circuitry for disabling receiver circuitry
`included in the receiver portion if the signal strength of the
`received signal is beloW a predetermined threshold.
`According to yet another aspect of the invention, a
`cellular communication system is provided, including: a
`netWork; a host computer coupled to the netWork; a plurality
`of base stations coupled to the netWork and communicating
`With the host computer, each of the base stations including
`a base station transmitter for transmitting Wireless commu
`nications and a base station receiver for receiving Wireless
`communications; and a plurality of mobile terminals each
`for communicating With the netWork by Way of at least one
`of the plurality of base stations, each of the plurality of
`mobile terminals having a mobile terminal receiver for
`receiving Wireless communications from at least one of the
`plurality of base stations; Wherein the receiver of at least one
`of the mobile terminals or base stations includes: a receiver
`portion for receiving information, the receiver portion being
`sWitchable betWeen a loW poWer consumption mode and an
`active mode; and a control circuit coupled to the receiver
`portion for selectively sWitching the receiver portion from
`the loW poWer consumption mode to the active mode by
`detecting an information signal to be received by the
`receiver, Whereby the receiver portion receives the informa
`tion signal in the active mode.
`To the accomplishment of the foregoing and related ends,
`the invention then, comprises the features hereinafter fully
`described and particularly pointed out in the claims. The
`folloWing description and the anneXed draWings set forth in
`detail certain illustrative embodiments of the invention.
`These embodiments are indicative, hoWever, of but a feW of
`the various Ways in Which the principles of the invention
`may be employed. Other objects, advantages and novel
`features of the invention Will become apparent from the
`folloWing detailed description of the invention When con
`sidered in conjunction With the draWings.
`
`10
`
`15
`
`25
`
`35
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram of a transceiver having a
`transmitter and receiver Which individually are sWitchable
`betWeen a loW poWer consumption mode (i.e., a “sleep
`mode”) and an active mode in accordance With the present
`invention;
`FIG. 2 is a schematic representation of a packet format in
`accordance With the present invention;
`FIG. 3 is a block diagram of the transceiver of FIG. 1
`shoWing in detail the receiver in accordance With the present
`invention;
`FIG. 4 is a ?oWchart indicating hoW a transceiver control
`circuit sets a RSSI threshold level in accordance With the
`present invention.
`FIG. 5 is a ?oWchart representing hoW a transceiver
`control circuit evaluates the RSSI signal, carrier sense signal
`
`55
`
`65
`
`6
`and/or length ?eld of an incoming signal and, based on such
`evaluation, sWitches the receiver betWeen a sleep mode and
`an active mode in accordance With the present invention;
`FIGS. 6A and 6B form a ?oWchart representing the
`operation of a transceiver control circuit for sWitching the
`transmitter betWeen a sleep mode and an active mode in
`accordance With the present invention;
`FIG. 7 is a timing diagram illustrating operation of the
`transceiver When sWitching the transmitter betWeen a sleep
`mode and an active mode in accordance With the embodi
`ment of FIGS. 6A and 6B;
`FIGS. 8A and 8B form a ?oWchart representing the
`operation of a transceiver control circuit for sWitching the
`transmitter betWeen a sleep mode and an active mode in
`accordance With another embodiment of the present inven
`tion;
`FIG. 9 is a partial timing diagram illustrating operation of
`the transceiver in accordance With the embodiment of FIGS.
`8A and 8B; and
`FIG. 10 is a system diagram of a cellular communication
`system utiliZing a plurality of transceivers in accordance
`With the present invention.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`The present invention Will noW be described With refer
`ence to the draWings in Which like reference numerals are
`used to refer to like elements throughout.
`Referring initially to FIG. 1, a transceiver in accordance
`With the present invention is generally designated 10. The
`transceiver 10 includes a radio transmitter 12 for transmit
`ting radio signals via an antenna 14. In addition, the trans
`ceiver 10 includes a radio receiver 16 for receiving radio
`signals via the antenna 14. An antenna sWitch 20 alloWs the
`transceiver 10 to transmit or receive signals depending on
`the position of the sWitch. When the sWitch 20 is in the
`transmit (TX) position, the antenna 14 is coupled to the
`output of the transmitter 12 via line 22 so that the transmitter
`12 can transmit information. Alternatively, When the sWitch
`20 is in the receive (RCV) position the antenna 14 is coupled
`to the input of the receiver 16 by Way of line 24. The receiver
`16 thereby receives information via the antenna 14.
`In the exemplary embodiments described herein, the
`transmitter 12 and receiver 16 are generally of conventional
`design With the exception of any speci?c modi?cations
`described herein. In general, the transmitter 12 and receiver
`16 are designed to transmit and receive, respectively, digital
`information modulated onto a radio frequency (rf) carrier. As
`is described more fully beloW in connection With FIG. 2, the
`digital information is transmitted and received in the form of
`packets. The transmitter 12 is of the type Which can be
`selectively sWitched betWeen a loW poWer consumption
`mode (i.e., a sleep mode) and an active mode as discussed
`above. More speci?cally, When the transmitter 12 is in the
`sleep mode, the supply of poWer to the poWer ampli?er (not
`shoWn), modulation circuitry (not shoWn), and/or various
`other poWer consuming components Within the transmitter
`12 is cut off or otherWise reduced. In this manner, the load
`on a battery 26 used to poWer the transceiver 10 is reduced.
`The transmitter 12 is selectively sWitched betWeen the sleep
`mode and active mode based on a control signal provided to
`a sleep/active input 28. The operation of the transceiver 10
`in relation to sWitching the transmitter 12 betWeen a sleep
`mode and an active mode is described in more detail beloW
`in relation to FIG. 6A thru FIG. 9.
`The receiver 16 is also of a type Which can be sWitched
`betWeen a sleep mode and an active mode. While the
`
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`US 6,236,674 B1
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`10
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`15
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`7
`receiver 16 is in a sleep mode, the power supplied to
`non-essential circuitry Within the receiver 16 (i.e., circuitry
`not necessary for operation during the sleep mode) is cut off
`or otherWise reduced. Hence, the load on the battery 26 to
`poWer the transceiver 10 again is reduced. HoWever, unlike
`the above-discussed conventional systems in Which a
`receiver in a poWer savings mode can only receive infor
`mation at predetermined times, the receiver 16 of the present
`invention can receive information at any time. Speci?cally,
`the receiver 16 is capable of sWitching from a sleep mode to
`an active mode substantially instantaneously as a signal is
`received. As a result, the receiver 16 is able to remain in a
`sleep mode until such time as an incoming signal is detected.
`Details regarding the operation of the transceiver 10 in
`relation to sWitching the receiver 16 betWeen a sleep mode
`and active mode are provided beloW With reference to FIGS.
`3—5.
`Continuing to refer to FIG. 1, the transceiver 10 further
`includes a control circuit 30 Which processes the information
`Which is communicated via the transceiver 10. In the pre
`ferred embodiment, the control circuit 30 is made up of a
`medium access controller (MAC) Which is connected to the
`transmitter 12 and receiver 16 by Way of lines 32 and 34,
`respectively. The MAC 30 provides a RCV/T X control
`signal on line 36 to the antenna sWitch 20 in order to
`selectively sWitch the antenna sWitch 20 betWeen the trans
`mit and receive positions. Additional control signals are
`provided by the MAC 30 in order to control the active/sleep
`states of the transmitter 12 and receiver 16. More
`particularly, the MAC 30 provides a sleep/active control
`signal on line 38 to the input 28 in order to selectively sWitch
`the transmitter 12 betWeen the sleep and active modes as is
`discussed more fully