Wireless communications device allowing a soft handoff procedure in a mobile communications system

• US 6,728,528 B1
• Filed: 06/28/1999
• Issued: 04/27/2004
• Est. Priority Date: 06/28/1999
• Status: Expired due to Term

• Current Assignee: Alpha Industries Incorporated (Skyworks Solutions Incorporated)
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Loke, Aravind
• Primary Examiner(s): Kincaid, Lester G.
• Application Number:
  US09/342,165
• Time in Patent Office: 1,765 Days
• Field of Search: 455/442, 455/303, 455/313, 455/314, 455/315, 455/318, 455/323, 455/326, 455/552, 455/553, 455/269, 455/273, 455/275, 455/76, 370/335, 370/342, 370/331, 375/150, 375/340, 375/343, 375/347, 375/349
• US Class Current: 455/318
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A wireless communications device includes an antenna that receives a first signal at a first radio frequency and a second signal at a second radio frequency and converts the first and second signals into a composite radio frequency (RF) signal. A first oscillator outputs a first oscillator signal at a first frequency and a second oscillator outputs a second oscillator signal at a second frequency. A demodulator receives the composite RF signal and the first and second oscillator signals. The oscillator signals are selected so that the demodulator generates a low frequency signal with components of the first and second signals occupying a common frequency band. The wireless communications device allows executing a “Soft Handoff” even when the first and second radio frequencies are different.

Claims

1. A wireless communications device comprising:

a first input configured to receive an input signal which comprises a first component allocated within a first frequency band and a second component allocated within a second frequency band;

a first oscillator configured to generate a first oscillator signal at a first oscillator frequency;

a second oscillator configured to generate a second oscillator signal at a second oscillator frequency; and

a mixer configured to receive the input signal, the first oscillator signal and the second oscillator signal, the mixer configured to convert at least a portion of the first component and at least a portion of the second component to a third frequency band.

2. The device of claim 1, wherein the first oscillator frequency is different than the second oscillator frequency.

3. The device of claim 1, wherein the mixer generates an output signal comprising output frequencies located within the third frequency band.

4. The device of claim 3, further comprising a processor configured to process the output signal.

5. The device of claim 1, further comprising a filter having a filter characteristic selected to isolate the third frequency band.

6. The device of claim 1, wherein the third frequency band comprises a first difference component corresponding to a difference between the first component allocated within the first frequency band and the first oscillator signal at the first oscillator frequency.

7. The device of claim 1, wherein the third frequency band comprises a second difference component corresponding to a difference between the second component allocated within the second frequency band and the second oscillator signal at the second oscillator frequency.

8. A device, comprising:

at least a first terminal which is configured to receive a first signal within a first frequency band from a first source wherein the first signal is filtered to produce a filtered first signal within the first frequency band, and a second signal within a second frequency band from a second source wherein the second signal is filtered to produce a filtered second signal within the second frequency band;

at least a second terminal which is configured to receive at least a first reference signal and a second reference signal; and

a mixer in communication with the filtered first and second signals and the second terminal, the mixer configured to generate a first difference component within a third frequency band, the first difference component comprising the difference between a portion of the filtered first signal within the first frequency band and the first reference signal, the mixer further configured to generate a second difference component within the third frequency band, the second difference component comprising the difference between a portion of the filtered second signal within the second frequency band and the second reference signal.

9. The device of claim 8, further comprising an amplifier coupled to the first terminal and configured to amplify the first and second signals.

10. The device of claim 8, further comprising a filter having a filter characteristic selected to isolate the third frequency band.

11. The device of claim 8, wherein the first difference component is approximately equal to the second difference component.

12. A wireless communications device comprising:

a first input configured to receive an input signal which comprises a first component having a first frequency allocated within a first frequency band and a second component having a second frequency allocated within a second frequency band;

a first oscillator configured to generate a first oscillator signal at a first oscillator frequency;

a second oscillator configured to generate a second oscillator signal at a second oscillator frequency; and

a mixer configured to receive the input signal, the first oscillator signal and the second oscillator signal, the mixer configured to convert at least a portion of the first component and at least a portion of the second component into a third frequency band, the portion of the first component having a first difference frequency corresponding to a difference between the first frequency and the first oscillator frequency and the portion of the second component having a second difference frequency corresponding to a difference between the second frequency and the second oscillator frequency, wherein the first difference frequency is approximately equal to the second difference frequency, both located within the third frequency band.