Software-defined transceiver for a wireless telecommunications system

• US 6,496,546 B1
• Filed: 07/15/1998
• Issued: 12/17/2002
• Est. Priority Date: 07/15/1998
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Mardani, Reza, Arunachalam, Sridhar, Pagano, Carmine James II, Tarallo, Joseph Anthony, Shan, Tiejun, Allpress, Stephen Alan
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US09/115,933
• Time in Patent Office: 1,616 Days
• Field of Search: 375/260, 375/270, 375/316, 375/321, 375/324, 375/328, 375/225, 375/329, 329/304, 455/226.3, 341/61, 708/313
• US Class Current: 375/316
• 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 1/001 Channel filtering, i.e. selecting a frequency channel within the SDR system multiplexing of multicarrier modulation signals being represented by different frequencies H04L5/06; multiplexing of multicarrier modulation signals H04L5/023
• CPC Class Codes: H04B 1/0017 Digital filtering H04B1/001 takes precedence; digital filters per se H03H17/00
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

A technique for receiving and transmitting wireless telecommunications through use of a generic architecture is disclosed. The present invention mitigates the complexity of different transceiver operations by allowing a generic architecture to be used in a variety of situations with different channels and different telecommunications standards. An illustrative embodiment of the present invention comprises: receiving uplink analog RF signals at a base station; converting the uplink analog wide-band RF signals into IF uplink digital signals at an analog-to-digital converter; converting the IF uplink digital signals into a number of uplink channels; and demodulating selected narrow-band uplink channels from the total number of narrow-band uplink channels.

Claims

1. A method comprising:

receiving an uplink analog wide-band RF signal at a base station;

converting, in a first converting step, said uplink analog wide-band RF signal into an IF uplink analog wide-band signal having a total bandwidth W_IF and encompassing a quantity N of narrow-band uplink channels;

converting, in a second converting step, said IF uplink analog wide-band signal into an IF uplink digital signal;

wide-band down-converting said IF uplink digital signal into said N narrow-band uplink channels wherein said wide-band down-converting includes using a multi-rate filter bank,

rejecting at least some of said down-converted narrow-band uplink channels;

demodulating at least some non-rejected narrow-band uplink channels.

2. The method of claim 1, wherein said second converting step includes sampling said IF uplink analog wide-band signal at a first sampling rate i to obtain said IF uplink digital signal.

3. The method of claim 2, further including a step of sampling said IF uplink digital signal at a second sampling rate j when a ratio, Nr, of total bandwidth W_IF to a bandwidth required for each narrow-band uplink channel, W, is not an integer.

4. The method of claim 3, wherein said step of sampling at said second sampling rate j includes decimating the IF uplink digital signal at a rate of i*(Nr/N).

5. The method of claim 2, further including a step of resampling said IF uplink digital signal at a sampling rate j that is equal to the sampling rate i when a ratio, Nr, of total bandwidth W_IF to a bandwidth required for each narrow-band uplink channel, W, is an integer.

6. The method of claim 2, wherein said step of demodulating includes resampling narrow-band uplink channels using one of a cascaded integrator comb (CIC) filter and a Farrow-Filter followed by an array conversion filter using a nearest neighbor rule and linear interpolation.

7. The method of claim 1, wherein said multi-rate filter bank includes cascaded polyphase filters.

8. The method of claim 1, wherein the step of rejecting at least some of said down-converted narrow-band uplink channels comprises avoiding further processing of uplink channels to be rejected after said step of wide-band down-converting.

9. A wireless telecommunications system comprising:

a receiver for receiving an uplink analog wide-band RF signal and for converting said uplink analog wide-band RF signal into an IF uplink analog wide-band signal having a total bandwidth, W_IF, and encompassing a quantity N of narrow-band uplink channels;

an analog-to-digital converter for converting said IF uplink wide-band analog signal into an IF uplink digital signal;

a controller for wide-band down-converting said IF uplink digital signal into said N narrow-band uplink channels wherein said controller is operative to implement a multi-rate filter bank for wide-band down-converting of said IF uplink digital signal; and

a demodulator for demodulating a quantity M of said N narrow-band uplink channels, said controller being operative to reject a quantity N−

M of said narrow band uplink channels.

10. The system of claim 9, wherein said analog-to-digital converter is operative to sample said IF uplink analog wide-band signal at a first sampling rate i to obtain said IF uplink digital signal.

11. The system of claim 10, wherein said controller is operative to implement resampling of said IF uplink digital signal at a second sampling rate j when a ratio, Nr, of total bandwidth W_IF to a bandwidth required for each narrow-band uplink channel, W, is not an integer.

12. The system of claim 11, wherein said controller is operative to implement decimating the IF uplink digital signal at a rate of i*(Nr/N).

13. The system of claim 10, wherein said controller is operative to implement resampling of said IF uplink digital signal at a second sampling rate j that is equal to the sampling rate i when a ratio, Nr, of total bandwidth W_IF to a bandwidth required for each narrow-band uplink channel, W, is an integer.

14. The system of claim 9, wherein said demodulator is operative to resample narrow-band uplink channels using a cascaded integrator comb (CIC) filter.

15. The system of claim 9, wherein said demodulator is operative to resample narrow-band uplink channels using a Farrow-Filter followed by an array conversion filter according to a nearest neighbor rule and linear interpolation.

16. The system of claim 9, wherein the multi-rate filter bank implemented by said controller includes cascaded polyphase filters.