Multi-band, multi-mode spread-spectrum communication system

• US 5,790,587 A
• Filed: 06/07/1995
• Issued: 08/04/1998
• Est. Priority Date: 05/13/1991
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Omnipoint Corp. (Deutsche Telekom AG)
• Inventors: Dixon, Robert C., Smith, Douglas G., Vanderpool, Jeffrey S.
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US08/483,514
• Time in Patent Office: 1,154 Days
• Field of Search: 455/305, 455/306, 455/188.1, 455/200.1, 375/316, 375/344, 375/200, 375/202, 375/208, 375/346, 375/260
• US Class Current: 375/147
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding
• 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 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/7071 with dynamic control of receiver resources
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04B 7/2634 for channel frequency control
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A technique for spread-spectrum communication which uses more than one mode and more than one frequency band. Selectable modes include narrowband mode and spread-spectrum mode, or cellular mode and microcellular mode. Selectable frequency bands include both licensed and unlicensed frequency bands, particularly frequency bands including the 902-928 MHz, 1850-1990 MHz, and 2.4-2.4835 GHz frequency bands. Spread-spectrum communication channels are 10 MHz or less in width. The frequency band onto which spread-spectrum signals are encoded may be changed upon a change in environment or other control trigger, such as establishment or de-establishment of communication with a private access network. A multi-band transmitter comprises a single frequency synthesizer and a frequency source (e.g., a local oscillator), coupled to a selectable band pass filter. A multi-band receiver capable of monitoring one or more frequency bands comprises bank of bandpass filters and a demodulator comprising a single frequency synthesizer and a frequency source.

Claims

1. An apparatus for receiving spread spectrum signals, comprising:

an antenna for receiving a first spread spectrum signal transmitted in a first frequency range and a second spread spectrum signal transmitted in a second frequency range;

a frequency synthesizer outputting a programmable frequency signal having a first frequency;

a filter coupled to said spread spectrum signals, said filter selectively outputting a filtered signal, said filtered signal comprising the first frequency range and the second frequency range;

a multiplier coupled to said filtered signal and said programmable frequency signal, said multiplier outputting a multiplied signal;

a spread spectrum demodulator coupled to said multiplied signal.

2. The apparatus of claim 1 wherein said frequency synthesizer comprises:

a reference frequency signal source;

a programmable divide-by-N counter;

a multiplier having inputs coupled to said programmable divide-by-N counter and said reference frequency signal course; and

a voltage-controlled oscillator having an input coupled to said multiplier, said voltage-controlled oscillator having an output coupled to said programmable divide-by-N counter.

3. The apparatus of claim 1 wherein a plurality of frequency ranges are monitored at once.

4. The apparatus of claim 1 wherein:

said first frequency range is defined by summation of said first frequency and a second frequency; and

said second frequency range is defined by a difference between said first frequency and said second frequency.

5. The apparatus of claim 4 wherein the spread spectrum demodulator demodulates the spread spectrum signals using a PN code.

6. The apparatus of claim 4 wherein the spread spectrum demodulator demodulates the spread spectrum signals using an M-ary spread spectrum technique.

7. The apparatus of claim 4 wherein said filter comprises:

a first band pass filter having a center filtering frequency defined by summation of said first frequency and said second frequency, and

a second band pass filter having a center filtering frequency defined by taking the difference between said first frequency and said second frequency.

8. The apparatus of claim 7 further comprising at least one switch coupled to an output of said first band pass filter and to an output of said second band pass filter.

9. The apparatus of claim 7 further comprising at least one switch coupled to an input of said first band pass filter and to an input of said second band pass filter.

10. A method for receiving spread spectrum signals, comprising the steps of:

receiving a first spread spectrum signal transmitted in a first frequency range and a second spread spectrum signal transmitted in a second frequency range;

generating with a frequency synthesizer a programmable frequency signal having a first frequency;

filtering said spread spectrum signals and selectively outputting a filtered signal, said filtered signal comprising the first frequency range and the second frequency range;

multiplying said filtered signal and said programmable frequency signal, and outputting a multiplied signal; and

spread spectrum demodulating said multiplied signal.

11. The method of claim 10 wherein a plurality of frequency ranges are monitored at once.

12. The method of claim 10 wherein:

said first frequency range is defined by summation of said first frequency and a second frequency, and

said second frequency range is defined by taking the difference between said first frequency and said second frequency.

13. The method of claim 12 wherein the spread spectrum demodulator demodulates the spread spectrum signals using a PN code.

14. The method of claim 12 wherein the spread spectrum demodulator demodulates the spread spectrum signals using an M-ary spread spectrum technique.

15. The apparatus of claim 12 wherein said filtering step comprises:

band pass filtering said spread spectrum signals with a center filtering frequency defined by the summation of said first frequency and said second frequency, and

band pass filtering said spread spectrum signals with a center filtering frequency defined by taking the difference between said first frequency and said second frequency.

16. The method of claim 15 further comprising the step of selectively switching the inputs to said filtering step.

17. The method of claim 15 further comprising the step of selectively switching the outputs from said filtering step.

18. A method for receiving multi-band spread spectrum signals, comprising the steps of:

receiving a first spread spectrum signal transmitted in a first frequency band and a second spread spectrum signal transmitted in a second frequency band;

generating with a frequency synthesizer a synthesized signal comprising a first frequency;

filtering said spread spectrum signals and outputting a first filtered signal and a second filtered signal, said first filtered signal falling within the first frequency band defined by the summation of said first frequency and a second frequency, said second filtered signal falling within the second frequency band defined by taking the difference between said first frequency and said second frequency;

selectively modulating said first and second filtered signals with said synthesized signal and outputting a modulated signal; and

spread spectrum demodulating said modulated signal.

19. An apparatus for receiving spread spectrum signals, comprising:

means for receiving spread spectrum signals transmitted at a first center frequency and at a second center frequency;

a frequency synthesizer outputting a synthesized signal comprising a programmable frequency;

a filter coupled to said spread spectrum signals, said filter outputting a filtered signal at either the first center frequency or the second center frequency, said first center frequency defined by summation of said programmable frequency and an intermediate frequency, said second center frequency defined by taking the difference between said programmable frequency and said intermediate frequency;

a multiplier coupled to said filtered signal and said synthesized signal, said multiplier outputting a multiplied signal;

a spread spectrum demodulator coupled to said multiplied signal.