Multiple mode capable radio receiver device

• US 6,169,733 B1
• Filed: 05/12/1997
• Issued: 01/02/2001
• Est. Priority Date: 05/12/1997
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Lee, Michael C. G.
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US08/855,846
• Time in Patent Office: 1,331 Days
• Field of Search: 375/267, 375/299, 375/349, 375/356, 375/347, 455/59, 455/131, 455/139, 455/161.2, 455/132, 455/150.1, 455/552, 455/553, 370/312, 370/320, 370/321, 370/334, 370/335, 370/342, 370/465, 370/466, 370/481, 370/486, 370/487, 370/318, 370/319, 370/337
• US Class Current: 370/342
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A mobile handset is able to receive and transmit to base stations operating in compliance with different standards, for example CDMA, TDMA or AMPS. The mobile handset converts the received signal down to baseband and digitizes only a single channel at a time rather than the whole band. The channel chosen is the biggest of the various transmission systems used. For example, the channel widths for CDMA, TDMA and AMPS are, respectively 1.25 MHz, 30 KHz and 30 KHz. Accordingly to deal with these three systems a 1.25 MHz channel is digitized. Thereafter a digital signal processor determines which of the three systems is being used and appropriate processing and demodulation is carried out.

Claims

1. A radio receiver comprising a first receiver portion for reception of radio signals encoded according to a plurality of different protocols but transmitted within a first common frequency band, each protocol specifying a bandwidth for a single communication channel, and a second receiver portion connected in parallel to the first receiver portion for reception of radio signals encoded according to a second plurality of different protocols but transmitted within a second common frequency band, each protocol specifying a bandwidth for a single communication channel, the first receiver portion comprising:

at least one downconversion stage for deriving baseband information in a selected frequency band having a width substantially equal to a largest one of the channel bandwidths used in the first plurality of different protocols;

the second receiver portion comprising;

at least one downconversion stage for deriving baseband information in a selected frequency band having a width substantially equal to a largest one of the channel bandwidths used in the second plurality of different protocols;

the radio receiver further comprising;

an A/D conversion stage connected to outputs of the first and second receiver portions for converting the baseband information in the selected frequency band to digital information; and

a digital signal processor for processing the digital information corresponding to the baseband information in the selected frequency band, whereby the particular protocol used can be discerned and the digital information processed accordingly.

2. A radio receiver according to claim 1, wherein the digital signal processor first determines whether the digital information corresponds to a single channel of one of the protocols or to multiple channels of another protocol.

3. A radio receiver according to claim 2, wherein, if the digital signal processor determines that the digital information corresponds to multiple channels of another protocol, the digital signal processor subsequently filters out a single channel of the other protocol.

4. A radio receiver according to claim 1, wherein, with respect to the first receiver portion, the first common frequency band is 869-894 MHz and the different protocols are AMPS, CDMA and TDMA, and the selected frequency bandwidth of the baseband information is 1.25 MHz and, with respect to the second receiver portion, the second common frequency band is 1930-1990 MHz and the different protocols are CDMA and TDMA, and the selected frequency bandwidth of the baseband information is 1.25 MHz.

5. A radio receiver according to claim 2, wherein, with respect to the first receiver portion, the first common frequency band is 869-894 MHz and the different protocols are AMPS, CDMA and TDMA, and the selected frequency bandwidth of the baseband information is 1.25 MHz and, with respect to the second receiver portion, the second common frequency band is 1930-1990 MHz and the different protocols are CDMA and TDMA, and the selected frequency bandwidth of the baseband information is 1.25 MHz.

6. A radio receiver according to claim 3, wherein, with respect to the first receiver portion, the first common frequency band is 869-894 MHz and the different protocols are AMPS, CDMA and TDMA, and the selected frequency bandwidth of the baseband information is 1.25 MHz and, with respect to the second receiver portion, the second common frequency band is 1930-1990 MHz and the different protocols are CDMA and TDMA, and the selected frequency bandwidth of the baseband information is 1.25 MHz.

7. A radio receiver for reception of radio signals encoded according to a plurality of different protocols but transmitted within a common frequency band, each protocol specifying a bandwidth for a single communication channel, the receiver comprising:

at least one downconversion stage for deriving baseband information in a selected frequency band having a width substantially equal to a largest one of the channel bandwidths used in the different protocols;

an A/D conversion stage for converting the baseband information in the selected frequency band to digital information; and

a digital signal processor for processing the digital information corresponding to the baseband information in the selected frequency band, wherein the digital signal processor first determines whether the digital information corresponds to a single channel of a first particular one of the protocols, if the digital signal processor determines that the digital information corresponds to a single channel of the first protocol the digital signal processor processes the digital information according to the first protocol, if the digital signal processor determines that the digital information does not correspond to a single channel of the first protocol the digital signal processor subsequently filters out a single channel of another particular one of these protocols, determines whether the digital information in the filtered single channel corresponds to the other protocol and, if it does correspond, processes the digital information in the filtered single channel according to the other protocol.

8. A radio receiver according to claim 7, wherein the digital signal processor, if it determines that the digital information in the filtered single channel does not correspond to the other protocol, determines whether the digital information in the filtered single channel corresponds to a further protocol and, if it does correspond, processes the digital information according to the further protocol.

9. A radio receiver according to claim 7, wherein the common frequency band is 869-894 MHz, the first protocol is CDMA and the other protocol is one of TDMA and AMPS, and the selected bandwidth of the baseband information is 1.25 MHz.

10. A radio receiver according to claim 8, wherein the common frequency band is 869-894 MHz, the first protocol is CDMA, the other protocol is one of TDMA and AMPS and the further protocol is TDMA if the other protocol is AMPS and is AMPS if the other protocol is TDMA, and the selected bandwidth of the baseband information is 1.25 MHz.

11. A radio receiver according to claim 7, wherein the common frequency band is 1930-1990 MHz, the first protocol is CDMA and the other protocol is TDMA, and the selected bandwidth of the baseband information is 1.25 MHz.

12. A radio receiver according to claim 7, wherein the at least one downconversion stage comprises:

an amplifier;

a passband filter for passing the common frequency band;

a programmable RF synthesizer;

a mixer having inputs supplied by the passband filter and the RF synthesizer;

a filter connected to an output of the mixer having a passband width substantially equal to the largest one of the channel bandwidths used in the different protocols.

13. A radio receiver according to claim 7, wherein the at least one downconversion stage derives an inphase component and a quadrature component of the baseband information.

14. A method of processing radio signals encoded according to a plurality of different protocols but transmitted within a common frequency band, each protocol specifying a bandwidth for a single communication channel, the method comprising the steps of:

receiving a radio signal;

downconverting the radio signal to derive baseband information in a selected frequency band having a width substantially equal to a largest one of the channel bandwidths used in the different protocols;

performing an analog to digital conversion on the baseband information in the selected frequency band to obtain digital information;

processing the digital information to determine the particular protocol used; and

further processing the digital information according to the particular protocol determined;

wherein the step of processing the digital information to determine the particular protocol used comprises the substeps of;

determining whether the digital information corresponds to a single channel of a first particular one of the protocols;

if the digital information corresponds to a single channel of the first protocol, processing the digital information according to the first protocol;

if the digital information does not correspond to a single channel of the first protocol, filtering out a single channel of another one of the protocols;

determining whether the digital information in the filtered single channel corresponds to the other protocol and, if it does correspond, processing the digital information in the filtered single channel according to the other protocol.

15. A method according to claim 14, wherein the step of processing the digital information further comprises the substeps, in the event that the digital information in the filtered single channel does not correspond to the other protocol, of determining whether the digital information in the filtered single channel corresponds to a further protocol and, if it does correspond, processing the digital information according to the further protocol.

16. A method according to claim 14, wherein the common frequency band is 869-894 MHz, the first protocol is CDMA, the other protocol is one of TDMA and AMPS and the selected bandwidth of the baseband information is 1.25 MHz.

17. A method according to claim 15, wherein the common frequency band is 869-894 MHz, the first protocol is CDMA, the other protocol is one of TDMA and AMPS, the further protocol is TDMA if the other protocol is AMPS and is AMPS if the other protocol is TDMA, and the selected bandwidth of the baseband information is 1.25 MHz.

18. A method according to claim 14, wherein the common frequency band is 1930-1990 MHz, the first protocol is CDMA, the other protocol is TDMA, and the selected bandwidth is 1.25 MHz.