System and process for shared functional block CDMA and GSM communication transceivers

• US 6,584,090 B1
• Filed: 04/23/1999
• Issued: 06/24/2003
• Est. Priority Date: 04/23/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Abdelgany, MohyEldeen Fouad, Laub, Dana Vincent
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Iqbal, Khawar
• Application Number:
  US09/298,315
• Time in Patent Office: 1,523 Days
• Field of Search: 455/426, 455/74, 455/82, 455/83, 455/84, 455/86, 455/552, 455/553, 455/127, 455/93, 455/102, 455/118, 455/142, 370/342, 370/345, 370/347, 370/320, 375/216, 375/219
• US Class Current: 370/342
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/707 using direct sequence modulation

Abstract

A communication system for communicating CDMA and GSM transmit and receive RF information signals through one or more antennas is disclosed. The communication system is comprised of a transmitting unit, a receiving unit, and at least one antenna. The transmitting unit modulates and upconverts a transmit baseband information signal to generate a CDMA transmit RF information signal and a GSM transmit RF information signal. The receiving unit downconverts and demodulates a CDMA receive RF information signal and a GSM receive RF information signal to generate a receive baseband information signal. One or more antennas are coupled to the transmitting unit and receiving unit for transmitting the CDMA transmit RF information signal and the GSM transmit RF information signal, and receiving the CDMA receive RF information signal and the GSM receive RF information signal. The transmitting unit comprises a modulator for modulating a transmit IF LO frequency with the transmit baseband information signal to generate a transmit IF information signal. It also includes a plurality of upconverters for upconverting the transmit IF information signal with a GSM transmit RF LO frequency to generate a GSM transmit RF information signal, and for upconverting the transmit IF information signal with a CDMA transmit RF LO frequency to generate at least one CDMA transmit RF information signal. The receiving unit comprises a downconverter for downconverting a CDMA receive RF information signal with a receive RF LO frequency to generate a receive IF information signal, and for downconverting at least one GSM receive RF information signal with the receive RF LO frequency to generate a receive IF information signal. It also includes a demodulator for demodulating the receive IF information signal with a receive IF LO frequency to generate a receive baseband information signal.

Claims

1. A cellular communication system for communicating code division multiple access (CDMA) and global system for mobile communication (GSM) transmit and receive first information signals, comprising:

a transmitting unit for modulating and upconverting a transmit baseband information signal to generate at least one CDMA transmit first information signal and at least one GSM transmit first information signal, the transmitting unit including a modulator for modulating a transmit second local oscillator (LO) frequency with the transmit baseband information signal to generate a transmit second information signal, and a plurality of upconverters for upconverting the transmit second information signal with a GSM transmit first LO frequency to generate the at least one GSM transmit first information signal and for upconverting the transmit second information signal with a CDMA transmit first LO frequency to generate the at least one CDMA transmit first information signal;

a transit variable gain amplifier coupled between the modulator and the plurality of upconverters for controllably normalizing the transmit second information signal power level for a plurality of CDMA cellular communication channels; and

a receiving unit for downconverting and demodulating at least one CDMA receive first information signal and at least one GSM receive first information signal to generate a receive baseband information signal, the receiving unit including at least one downconverter for downconverting the at least one CDMA receive first information signal with a receive first LO frequency to generate a receive second information signal and for downconverting the at least one GSM receive first information signal with the receive first LO frequency to generate the receive second information signal, and a demodulator for demodulating the receive second information signal with a receive second LO frequency to generate the receive baseband information signal.

2. The communication system as recited in claim 1, wherein the plurality of upconverters comprises a translation loop for upconverting the transmit second information signal with the GSM transmit first LO frequency and an upconverter mixer for upconverting the transmit second information signal with the CDMA transmit first LO frequency.

3. A communication system as recited in claim 2, the receive first LO frequency comprising a CDMA receive first LO frequency and a GSM receive first LO frequency, the at least one downconverter comprising:

a CDMA receive low noise amplifier (LNA) coupled for amplifying the CDMA receive first information signal, a CDMA receive image reject filter coupled for filtering an output of the CDMA receive LNA, a CDMA receive downconverter mixer coupled for receiving and mixing an output of the CDMA receive image reject filter and the CDMA receive first LO frequency, and a CDMA receive filter coupled for filtering an output of the CDMA receive downconverter mixer;

a preselector filter coupled for filtering the at least one GSM receive first information signal, a GSM receive LNA coupled for amplifying an output of the preselector filter, a GSM receive image reject filter coupled for filtering an output of the GSM receive LNA, a GSM receive downconverter mixer coupled for receiving and mixing an output of the GSM receive image reject filter and the GSM receive first LO frequency, and a GSM receive filter coupled for filtering an output of the GSM receive downconverter mixer; and

a receive variable gain amplifier (VGA) selectively couplable to the CDMA receive filter and the GSM receive filter for amplifying an output of the CDMA receive filter and an output of the GSM receive filter.

4. A communication system as recited in claim 3, further including:

a CDMA first LO frequency generator for generating the CDMA receive first LO frequency and the CDMA transmit first LO frequency, a GSM first LO frequency generator for generating the GSM receive first LO frequency and the GSM transmit first LO frequency, a receive second LO frequency generator for generating the receive second LO frequency, and a transmit second LO frequency generator for generating the transmit second LO frequency.

5. A communication system as recited in claim 2, the receive first LO frequency comprising a CDMA receive first LO frequency and a GSM receive first LO frequency, the at least one downconverter comprising:

a variable gain attenuator coupled for attenuating the at least one CDMA receive first information signal, a preselector filter coupled for filtering the at least one GSM receive first information signal, a common receive LNA selectively couplable to the variable gain attenuator and the preselector filter for amplifying an output of the variable gain attenuator and the preselector filter, and a CDMA receive image reject filter and a GSM receive image reject filter selectively couplable to the common receive LNA for filtering an output of the common receive LNA; and

a common receive downconverter mixer selectively couplable to the CDMA receive image reject filter and the GSM receive image reject filter for mixing an output of the CDMA receive image reject filter and an output of the GSM receive image reject filter with the receive first LO frequency, a CDMA receive filter coupled in parallel with a GSM receive filter for filtering an output of the common receive downconverter mixer, and a receive VGA selectively couplable to the CDMA receive filter and the GSM receive filter for amplifying an output of the CDMA receive filter and an output of the GSM receive filter.

6. A communication system as recited in claim 5, further including:

a CDMA first LO frequency generator for generating the CDMA receive first LO frequency and the CDMA transmit first LO frequency, a GSM first LO frequency generator for generating the GSM receive first LO frequency and the GSM transmit first LO frequency, a receive second LO frequency generator for generating the receive second LO frequency, and a transmit second LO frequency generator for generating the transmit second LO frequency; and

a receive first LO frequency power combiner coupled for receiving and combining the CDMA receive first LO frequency and the GSM receive first LO frequency to generate the receive first LO frequency.

7. A communication system as recited in claim 2, the receive first LO frequency comprising a CDMA receive first LO frequency and a GSM receive first LO frequency, the at least one downconverter comprising:

a variable gain attenuator coupled for attenuating the at least one CDMA receive first information signal, a CDMA receive LNA coupled for amplifying an output of the variable gain attenuator, a CDMA receive image reject filter coupled for filtering an output of the CDMA receive LNA, a CDMA receive downconverter mixer coupled for receiving and mixing an output of the CDMA receive image reject filter and the CDMA receive first LO frequency, and a CDMA receive filter coupled for filtering an output of the CDMA receive downconverter mixer;

a preselector filter coupled for filtering the at least one GSM receive first information signal, a GSM receive LNA coupled for amplifying an output of the preselector filter, a GSM receive image reject filter coupled for filtering the output of the GSM receive LNA, a GSM receive downconverter mixer coupled for receiving and mixing an output of the GSM receive image reject filter and the GSM receive first LO frequency, and a GSM receive filter coupled for filtering the output of the GSM receive downconverter mixer; and

a receive VGA selectively couplable to the CDMA receive filter and the GSM receive filter for amplifying an output of the CDMA receive filter and an output of the GSM receive filter.

8. A communication system as recited in claim 7, further including:

a CDMA first LO frequency generator for generating the CDMA receive first LO frequency and the CDMA transmit first LO frequency, a GSM first LO frequency generator for generating the GSM receive first LO frequency and the GSM transmit first LO frequency, a receive second LO frequency generator for generating the receive second LO frequency, and a transmit second LO frequency generator for generating the transmit second LO frequency.

9. A communication system as recited in claim 2, the receive first LO frequency comprising a CDMA receive first LO frequency and a GSM receive first LO frequency, the at least one downconverter comprising:

a preselector filter coupled for filtering the at least one GSM receive first information signal, a common receive LNA selectively couplable for receiving and amplifying the at least one CDMA receive first information signal and an output of the preselector filter, a CDMA receive image reject filter and a GSM receive image reject filter selectively couplable to the common receive LNA for filtering an output of the common receive LNA; and

a common receive downconverter mixer selectively couplable to the CDMA receive image reject filter and the GSM receive image reject filter for mixing an output of the CDMA receive image reject filter and an output of the GSM receive image reject filter with the receive first LO frequency, a CDMA receive filter coupled in parallel with a GSM receive filter for filtering an output of the common receive downconverter mixer, and a receive VGA selectively couplable to the CDMA receive filter and the GSM receive filter for amplifying an output of the CDMA receive filter and an output of the GSM receive filter.

10. A communication system as recited in claim 9, further including:

a CDMA first LO frequency generator for generating the CDMA receive first LO frequency and the CDMA transmit first LO frequency, a GSM first LO frequency generator for generating the GSM receive first LO frequency and the GSM transmit first LO frequency, a receive second LO frequency generator for generating the receive second LO frequency, and a transmit second LO frequency generator for generating the transmit second LO frequency; and

a receive first LO power combiner coupled for receiving and combining the CDMA receive first LO frequency and the GSM receive first LO frequency to generate the receive first LO frequency.

11. A process for communicating code division multiple access (CDMA) and global system for mobile communication (GSM) transmit and receive first information signals, comprising:

modulating a transmit second LO frequency with a transmit baseband information signal to generate a transmit second information signal;

variably amplifying the transmit second information signal to controllably normalize the transmit second information signal power levels for a plurality of CDMA cellular communication channels;

upconverting the transmit second information signal with a CDMA transmit first LO frequency to generate at least one CDMA transmit first information signal or upconverting the transmit second information signal within a translation loop with a GSM transmit first LO frequency to generate at least one GSM transmit first information signal;

transmitting the at least one CDMA transmit first information signal or the at least one GSM transmit first information signal through at least one antenna; and

receiving at least one CDMA receive first information signal or at least one GSM receive first information signal from the at least one antenna, downconverting the at least one CDMA receive first information signal or the at least one GSM receive first information signal with a receive first LO frequency to generate a receive second information signal, and demodulating the receive second information signal with a receive second LO frequency to generate a receive baseband information signal.

12. A process as recited in claim 11, wherein the step of upconverting the transmit second information signal with a transmit first LO frequency to generate at least one CDMA transmit first information signal comprises mixing the transmit second information signal with the transmit first LO frequency, and

wherein the step of upconverting the transmit second information signal with a transmit first LO frequency to generate at least one GSM transmit first information signal comprises translation loop filtering the transmit second information signal with the transmit first LO frequency.

13. A process as recited in claim 11, wherein the step of downconverting the at least one CDMA receive first information signal and the at least one GSM receive first information signal with a receive first LO frequency to generate a receive second information signal comprises the steps of:

amplifying the at least one CDMA receive first information signal and the at least one GSM receive first information signal;

filtering the at least one CDMA receive first information signal and the at least one GSM receive first information signal to remove image noise produced in the amplifying step;

mixing the at least one CDMA receive first information signal and the at least one GSM receive first information signal with the receive first LO frequency to produce the receive second information signal;

filtering the receive second information signal to remove spurious frequencies generated during the mixing step; and

variably amplifying the receive second information signal.

14. A system for transmitting code division multiple access (CDMA) and global system for mobile communication (GSM) transmit first information signals, the system comprising:

at least one antenna for transmitting at least one CDMA transmit first information signal and at least one GSM transmit first information signal;

means coupled to the at least one antenna for modulating a transmit second LO frequency with a transmit baseband information signal to generate a transmit second information signal;

means for variably amplifying the transmit second information signal to controllably normalize the transmit second information signal power levels for a plurality of CDMA cellular communication channels;

means for upconverting the transmit second information signal with a transmit first LO frequency to generate the at least one CDMA transmit first information signal and means for upconverting the transmit second information signal within a translation loop using a GSM transmit first LO frequency to generate at least one GSM transmit first information signal; and

means for communicating the at least one CDMA transmit first information signal and the at least one GSM transmit first information signal to the at least one antenna.

15. A system as recited in claim 14, wherein the means for upconverting the transmit second information signal with the transmit first LO frequency to generate the at least one CDMA transmit first information signal comprises means for mixing the transmit second information signal with the transmit first LO frequency, and

wherein the means for upconverting the transmit second information signal with the transmit first LO frequency to generate the at least one GSM transmit first information signal comprises means for translation loop filtering the transmit second information signal with the transmit first LO frequency.

16. A system for receiving code division multiple access (CDMA) and global system for mobile communication (OSM) receive first information signals, the system comprising:

means for receiving at least one CDMA receive first information signal and at least one OSM receive first information signal;

means for downconverting the at least one CDMA receive first information signal and the at least one GSM receive first information signal with a receive first LO frequency to generate a receive second information signal;

means for van-ably attenuating the receive second information signal to normalize the receive second information signal power levels for a plurality of CDMA cellular communication channels; and

means for demodulating the receiving second information signal with a receive second LO frequency to generate a receive baseband information signal.

17. The system as recited in claim 16, wherein the means for downconverting the at least one CDMA receive first information signal and the at least one GSM receive first information signal with the receive first LO frequency to generate the receive second information signal, comprises:

means for amplifying the at least one CDMA receive first information signal and the at least one GSM receive first information signal;

means for filtering the at least one CDMA receive first information signal and the at least one GSM receive first information signal to remove image noise produced in the amplifying step;

means for mixing the at least one CDMA receive first information signal and the at least one GSM receive first information signal with the receive first LO frequency to produce the receive second information signal; and

means for filtering the receive second information signal to remove spurious frequencies generated during the mixing step.