Method and arrangement in a radio receiver system with several standards

• US 6,798,850 B1
• Filed: 02/25/2000
• Issued: 09/28/2004
• Est. Priority Date: 02/26/1999
• Status: Expired due to Fees

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wedin, Anders, Hellberg, Richard
• Primary Examiner(s): Fan, Chieh M.
• Application Number:
  US09/512,377
• Time in Patent Office: 1,677 Days
• Field of Search: 375/140, 375/141, 375/142, 375/144, 375/148, 375/150, 375/267, 375/279, 375/316, 375/324, 375/340, 375/347, 370/342, 370/347, 370/536
• US Class Current: 375/340
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/0014 using DSP [Digital Signal Processor] quadrature modulation and demodulation
• CPC Class Codes: H04B 1/0039 using DSP [Digital Signal Processor] quadrature modulation and demodulation
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 2201/70705 Rate detection
• CPC Class Codes: H04B 2201/7071 with dynamic control of receiver resources
• CPC Class Codes: H04L 7/0029 interpolation of received data signal
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A system, method, and receiver for receiving radio signals modulated according to different radio communication standards. Radio signals are received and downconverted to an intermediate frequency (IF) signal. An A/D-converter samples the IF signal at a sampling rate and digitizes the sampled signal into a digital signal. A channelizer filters out at least two modulated channels from the digital signal. A first ago channel is modulated according to a Time Division Multiple Access (TDMA) standard, and a second channel is modulated according to a Code Division Multiple Access (CDMA) standard. A first demodulating unit demodulates the TDMA channel, and a second demodulating unit demodulates the CDMA channel. Each of the demodulating units detects and, when needed, resamples each of the modulated channels individually, and delivers a corresponding demodulated channel. A Frequency Division Multiple Access (FDMA) channel may also be received and processed.

Claims

1. A multi-standards radio receiver system comprising:

an antenna unit for receiving a radio frequency (RF) signal;

a radio frequency unit for downconverting the received RF signal to an intermediate frequency (IF) signal;

an A/D-converter for sampling the IF signal with a certain sampling rate and digitizing the sampled signal into a digital signal;

a channelizer for filtering out at least two modulated channels from the digital signal, wherein a first channel is modulated according to a Time Division Multiple Access (TDMA) radio communication standard, and a second channel is modulated according to a Code Division Multiple Access (CDMA) radio communication standard, wherein the TDMA and CDMA communication standards have different chip or symbol rates, and the AND converter adjusts the sampling rate in accordance with the chip or symbol rate of a selected one of the TDMA or CDMA standards; and

at least two demodulating units, wherein a first demodulating unit demodulates the TDMA channel, and a second demodulating unit demodulates the CDMA channel, each of the demodulating units detecting and delivering a corresponding demodulated channel without having to resample the selected TDMA or CDMA channel.

2. The multi-standards radio receiver system of claim 1, wherein the TDMA demodulating unit includes a TDMA-demodulator/equalizing unit.

3. The multi-standards radio receiver system of claim 1, wherein the second demodulating unit includes a CDMA-demodulator/rake receiver unit.

4. The multi-standards radio receiver system of claim 1, wherein the system includes a plurality of CDMA receivers, each of which operates with a different bandwidth and chip rate.

5. A method of receiving different signal format standards in a multi-standards radio receiver system, said method comprising the steps of:

receiving radio frequency (RF) signals;

downconverting the received RF signals to an intermediate frequency (IF) signal;

sampling the IF signal with a certain sampling rate;

digitizing the sampled signal into a digital signal;

filtering out at least two modulated channels from the digital signal, a first channel being modulated according to a Time Division Multiple Access (TDMA) radio communication standard, and a second channel being modulated according to a Code Division Multiple Access (CDMA) radio communication standard, wherein the TDMA and CDMA communication standards have different chip or symbol rates;

adjusting the sampling rate of the sampling step in accordance with the chip or symbol rate of a selected one of the TDMA or CDMA standards;

demodulating the TDMA channel in a first demodulating unit; and

demodulating the CDMA channel in a second demodulating unit;

wherein each of the demodulating units detects and delivers a corresponding demodulated channel without having to resample the selected TDMA or CDMA channel.

6. The method of claim 5, wherein the second demodulating unit includes a CDMA-demodulator/rake receiver unit having a plurality of rake fingers.

7. The method of claim 6, wherein each rake finger correlates between a code sequence and incoming mutually different, non-uniformly sampled sets of data received in the RF signal.