Method and apparatus for performing an access procedure
DC CAFCFirst Claim
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1. A wireless code division multiple access (CDMA) subscriber unit comprising:
- a circuit configured to synchronize to a pilot signal transmitted by a base station associated with a CDMA network wherein, during idle periods of the subscriber unit, the circuit is further configured to remain synchronized to the pilot signal by periodically acquiring the pilot signal; and
a transmitter configured such that, when the subscriber unit is first accessing the CDMA network, the transmitter successively transmits signals until the subscriber unit receives from the base station an indication that a transmitted one of the signals has been detected by the base station, wherein each transmission of one of the signals by the transmitter, other than a transmission of a first one of the signals, is at an increased power level with respect to a prior transmission of another one of the signals and wherein the transmitted signals carry no data of the subscriber unit;
the transmitter further configured such that, subsequent to the subscriber unit receiving the indication, the transmitter facilitates closed loop power control with respect to a communication channel associated with the base station,wherein, prior to receiving the indication, the subscriber unit is not uniquely identified to the base station.
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Abstract
A base station for controlling transmission power during the establishment of a communication channel utilizes the reception of a short code during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional access code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The power of the short code is quickly increased until the signal is detected by the base station. Once the base station detects the short code, it transmits an indication that the short code has been detected.
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Citations
11 Claims
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1. A wireless code division multiple access (CDMA) subscriber unit comprising:
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a circuit configured to synchronize to a pilot signal transmitted by a base station associated with a CDMA network wherein, during idle periods of the subscriber unit, the circuit is further configured to remain synchronized to the pilot signal by periodically acquiring the pilot signal; and a transmitter configured such that, when the subscriber unit is first accessing the CDMA network, the transmitter successively transmits signals until the subscriber unit receives from the base station an indication that a transmitted one of the signals has been detected by the base station, wherein each transmission of one of the signals by the transmitter, other than a transmission of a first one of the signals, is at an increased power level with respect to a prior transmission of another one of the signals and wherein the transmitted signals carry no data of the subscriber unit; the transmitter further configured such that, subsequent to the subscriber unit receiving the indication, the transmitter facilitates closed loop power control with respect to a communication channel associated with the base station, wherein, prior to receiving the indication, the subscriber unit is not uniquely identified to the base station.
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2. A wireless code division multiple access (CDMA) subscriber unit comprising:
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a circuit configured to receive and down convert radio frequency signals to produce baseband signals, the baseband signals including a pilot signal and a paging message, the paging message being associated with the subscriber unit, wherein the circuit is further configured to synchronize to the pilot signal and demodulate the paging message; and a transmitter configured such that, when the subscriber unit is first accessing a CDMA network, the transmitter successively transmits signals until the subscriber unit receives from a base station associated with the network an indication that a transmitted one of the signals has been detected by the base station, wherein each transmission of one of the signals by the transmitter, other than a transmission of a first one of the signals, is at an increased power level with respect to a prior transmission of another one of the signals and wherein the transmitted signals carry no data of the subscriber unit; the transmitter further configured such that, subsequent to the subscriber unit receiving the indication, the transmitter transmits to the base station a message indicating to the base station that the subscriber unit wants to establish a radio connection with the base station over a communication channel to be indicated by the base station, wherein, prior to receiving the indication, the subscriber unit is not uniquely identified to the base station.
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3. A wireless code division multiple access (CDMA) subscriber unit comprising:
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a circuit configured to synchronize to a pilot signal transmitted by a base station associated with a CDMA network wherein, if the circuit becomes unsynchronized to the pilot signal during an idle period of the subscriber unit, the circuit is further configured to re-synchronize to the pilot signal; a transmitter configured such that, when the subscriber unit is first accessing the CDMA network, the transmitter successively transmits signals generated using a portion of a code until the subscriber unit receives from the base station an indication that a transmitted one of the signals has been detected by the base station, wherein each transmission of one of the signals by the transmitter, other than a transmission of a first one of the signals, is at an increased power level with respect to a prior transmission of another one of the signals; the transmitter further configured such that, subsequent to the subscriber unit receiving the indication, the transmitter transmits a signal generated using a remainder of the code, wherein, prior to receiving the indication, the subscriber unit is not uniquely identified to the base station.
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4. A base station for use in a code division multiple access (CDMA) network, comprising:
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a circuit configured to provide a pilot signal such that a subscriber unit is synchronized to the pilot signal and and re-synchronized to the pilot signal if the subscriber unit becomes unsynchronized to the pilot signal during an idle period; a receiver configured to receive, from a subscriber unit attempting to first access the network, a signal carrying no data of the subscriber unit; and a transmitter configured to transmit to the subscriber unit an indication that the signal carrying no data of the subscriber unit has been detected by the base station; the transmitter further configured such that, subsequent to the transmitter transmitting the indication to the subscriber unit, the transmitter facilitates closed loop power control with the subscriber unit with respect to a communication channel associated with the base station, wherein, prior to transmitting the indication, the base station has not uniquely identified the subscriber unit.
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5. A wireless code division multiple access (CDMA) subscriber unit comprising:
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a circuit configured to receive and down convert radio frequency signals to produce baseband signals, the baseband signals including a pilot signal and a paging message, the paging message being associated with the subscriber unit, wherein the circuit is further configured to synchronize to the pilot signal and demodulate the paging message; and a transmitter configured such that, when the subscriber unit is first accessing a CDMA network and wants to establish communications with a base station associated with the network over a communication channel to be indicated by the base station, the transmitter successively transmits signals until the subscriber unit receives from the base station an indication that a transmitted one of the signals has been detected by the base station, wherein each transmission of one of the signals by the transmitter, other than a transmission of a first one of the signals, is at an increased power level with respect to a prior transmission of another one of the signals; the transmitter further configured such that the transmitter transmits to the base station a message indicating to the base station that the subscriber unit wants to establish the communications with the base station over the communication channel to be indicated by the base station, the message being transmitted only subsequent to the subscriber unit receiving the indication, wherein the successively transmitted signals and the message are generated using a same code.
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6. A method for use in a code division multiple access subscriber unit for establishing communications between said subscriber unit and a base station, said method comprising:
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synchronizing to a pilot signal transmitted by said base station; after said synchronizing to the pilot signal, transmitting a plurality of different codes by said subscriber unit to said base station wherein each one of the plurality of different codes, other than a first one of the plurality of different codes, is transmitted at an increased power level with respect to a prior transmission of another one of the plurality of different codes; receiving an acknowledgement by said subscriber unit from said base station and ceasing transmitting the plurality of different codes, said acknowledgement indicating to said subscriber unit that said base station has received at least one of said plurality of different codes; and transmitting, in response to receipt of said acknowledgement, an access signal to facilitate communication initialization between said subscriber unit and said base station, said access signal as transmitted by said subscriber unit, and said plurality of different codes, as transmitted by said subscriber unit, being a function of a same code.
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7. A method for performing an access procedure in a code division multiple access subscriber unit for establishing communications between said subscriber unit and a base station, said method comprising:
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receiving radio frequency signals; down converting the received radio frequency signals to produce baseband signals, the baseband signals include a pilot signal and a paging message, the paging message being associated with the subscriber unit; synchronizing to the pilot signal; demodulating the paging message; after said demodulating the paging message and said synchronizing to the pilot signal, transmitting a first code to be used by said base station in establishing communication between said base station and said subscriber unit at a first power level, said first code not providing data of said subscriber unit; subsequently transmitting, with respect to said first code a same or a different code, at increasing power levels until an acknowledgement is received by the subscriber unit, reception of said acknowledgement by said subscriber unit indicating to said subscriber unit that the base station has detected transmission by the subscriber unit; and transmitting, in response to receipt of said acknowledgement, a signal by said subscriber unit as part of the access procedure wherein the signal includes a second code that is associated with the same or different code.
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8. A method performed by a code division multiple access subscriber unit for establishing communications between the subscriber unit and a base station, the method comprising:
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(a) synchronizing to a pilot signal transmitted by the base station; (b) after said synchronizing to the pilot signal, transmitting a code of a first type, wherein the code of the first type does not include data of the subscriber unit; (c) determining if the subscriber unit has received an acknowledgement signal from the base station, the acknowledgement signal being an indication to the subscriber unit that the base station has received a code of the first type; (d) repeating the transmitting of a code of a first type, each repeated transmission being at an increased power level with respect to a prior transmission of a code of the first type, until the subscriber unit has received the acknowledgement signal; and (e) transmitting a code of a second type after a determination is made that the subscriber unit has received the acknowledgement signal.
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9. A method for use in a code division multiple access subscriber unit for establishing communications between said subscriber unit and a base station, said method comprising:
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(a) receiving radio frequency signals; (b) down converting the received radio frequency signals to produce baseband signals, the baseband signals include a pilot signal and a paging message, the paging message being associated with the subscriber unit; (c) synchronizing to the pilot signal; (d) demodulating the paging message; (e) after said demodulating the paging message and said synchronizing to the pilot signal, transmitting a first one of a plurality of different codes by said subscriber unit to said base station; (f) if an acknowledgement is not received, transmitting another one of the plurality of different codes by said subscriber unit to said base station; (g) repeating step (f) until an acknowledgement is received by said subscriber unit from said base station, said acknowledgement indicating to said subscriber unit that said base station has received at least one of said different codes; and (h) transmitting, in response to receipt of said acknowledgement, an access signal to facilitate communication initialization between said subscriber unit and said base station, said access signal, as transmitted by said subscriber unit, and said different codes, as transmitted by said subscriber unit, being a function of a same code.
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10. A subscriber unit operable to perform an access procedure in a code division multiple access system for establishing communications between said subscriber unit and a base station, said subscriber unit comprising:
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a circuit configured to synchronize to a pilot signal transmitted by said base station wherein, the circuit is further configured to re-synchronize to the pilot signal if the subscriber unit becomes unsynchronized to the pilot signal during an idle period of the subscriber unit; a transmitter; and a processor configured to control said transmitter to transmit a first code to be used by said base station in establishing communication between said base station and said subscriber unit at a first power level, said first code not providing data of said subscriber unit, wherein said processor is further configured to control said transmitter to subsequently transmit, with respect to said first code a same or a different code, at increasing power levels until an acknowledgement is received by the subscriber unit, reception of said acknowledgement by said subscriber unit indicating to said subscriber unit that the base station has detected transmission by the subscriber unit, and said processor is further configured to control said transmitter to transmit, in response to receipt of said acknowledgement, a signal by said subscriber unit as part of the access procedure wherein the signal includes a second code that is associated with the same or different code.
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11. A subscriber unit for performing an access procedure for establishing communications between said subscriber unit and a base station, said subscriber unit comprising:
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a circuit configured to synchronize to a pilot signal transmitted by the base station wherein, the circuit is further configured to re-synchronize to the pilot signal if the subscriber unit becomes unsynchronized to the pilot signal during an idle period; a processor configured to control a transmitter such that the transmitter transmits a first one of a plurality of different codes by said subscriber unit to said base station; a receiver configured to receive an acknowledgement wherein if said acknowledgement is not received, the processor is configured to control the transmitter such that the transmitter transmits another one of the plurality of different codes by said subscriber unit to said base station; the processor configured to control said transmitter such that said transmitter repeats the transmitting of another one of the plurality of different codes until said acknowledgement is received by said subscriber unit from said base station, said acknowkdgement indicating to said subscriber unit that said base station has received at least one of said different codes; and said processor further configured to control the transmitter such that the transmitter transmits, in response to receipt of said acknowledgement, an access signal to facilitate communication initialization between said subscriber unit and said base station, said access signal as transmitted by said subscriber unit, and said plurality of different codes, as transmitted by said subscriber unit, being a function of a same code.
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Specification