Transmission and reception of signals in a communication systems

• US 5,974,319 A
• Filed: 11/21/1997
• Issued: 10/26/1999
• Est. Priority Date: 06/25/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Rader, Barry M., Kotzin, Michael D., Menich, Barry J.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/975,980
• Time in Patent Office: 704 Days
• Field of Search: 455/436, 455/437, 455/442, 455/443, 455/524, 455/525, 455/552, 455/553, 455/62-63, 455/71, 455/67.1, 455/101-103, 455/70, 375/200, 375/206, 370/319-321, 370/330, 370/477
• US Class Current: 455/436
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface

Abstract

A dual-mode mobile station (125) transmits an AMPS signal (Td AMPS) concurrently during transmission of a DS CDMA signal (Td DS CDMA) for purposes of handoff of the mobile station from the DS CDMA system to AMPS. Scanning receivers (221) at surrounding AMPS base-stations (135-138) measure the quality of the AMPS signal (Td AMPS) and determine the best base-station for handoff. To ensure a strong signal during concurrent transmission, other mobile stations not undergoing handoff are instructed to notch their transmissions during transmission by mobile station (125) of the AMPS signal (Td AMPS).

Claims

1. A method of transmitting and receiving signals between unlike communication systems comprising the steps of:

determining a need to handoff between a first base station and a second base station, wherein the first base station utilizes a wideband system protocol and the second base station utilizes a narrowband system protocol;

transmitting a wideband signal having a predetermined bandwidth from a mobile station, the wideband signal being incompatible with the second base station;

transmitting from the mobile station, a narrowband signal having a bandwidth within said predetermined bandwidth of said wideband signal, said narrowband signal transmitted concurrently with transmission of said wideband signal, the narrowband signal being incompatible with the first base station;

receiving, at the second base station, said narrowband signal having a bandwidth within said predetermined bandwidth of said wideband signal; and

processing, at the second base station, said narrowband signal for the purposes of handing off the mobile station from the first base station to the second base station.

2. The method of claim 1 wherein said step of transmitting a wideband signal having a predetermined bandwidth from a mobile station further comprises the step of transmitting said narrowband signal having a bandwidth within said predetermined bandwidth of said wideband signal from said mobile station during communication with a wideband communication system.

3. The method of claim 2 wherein said wideband communication system further comprises a code division multiple access (CDMA) communication system.

4. The method of claim 1, wherein said narrowband system protocol is used in a narrowband communication system, said narrowband communication system further comprises one of either AMPS or NAMPS.

5. The method of claim 1 wherein other mobile stations transmitting a wideband signal having said predetermined bandwidth are instructed to not transmit during transmission of said narrowband signal by said mobile station.

6. A method comprising the steps of:

transmitting, from a mobile station, a signal having a predetermined bandwidth and is compatible with a first communication system;

transmitting, from the mobile station, a signal incompatible with the first communication system, compatible with a second communication system and having a bandwidth within the predetermined bandwidth of the signal compatible with the first communication system, said transmission of the signal compatible with the second communication system transmitted concurrently with transmission of said signal compatible with the first communication system;

receiving, at a base station, the signal compatible with the second communication system; and

processing, at said base station, the received signal compatible with said second communication system for the purposes of handing off the mobile station.

7. The method of claim 6 wherein said step of transmitting a signal having a predetermined bandwidth and is compatible with a first communication system further comprises the step of transmitting a wideband signal having a wide bandwidth and is compatible with a code division multiple access (CDMA) communication system.

8. The method of claim 6 wherein said step of transmitting a signal compatible with a second communication system and having a bandwidth within the predetermined bandwidth of the signal compatible with the first communication system further comprises the step of transmitting a narrowband signal compatible with AMPS or NAMPS and having a narrow bandwidth within the predetermined bandwidth of the signal compatible with the first communication system.

9. The method of claim 6 wherein other mobile stations transmitting on the first communication system are instructed to not transmit during transmission of said narrowband signal by said mobile station.

10. The method of claim 6 wherein said step of processing the received signal compatible with said second communication system further comprises the step of processing the received signal compatible with said second communication system for purposes of handing off the mobile station from the first communication system to the second communication system.

17. The communication system of claim 6 wherein said means for transmitting a signal having a predetermined bandwidth and is compatible with a first communication system further comprises means for transmitting a wideband signal having a wide bandwidth and is compatible with a code division multiple access (CDMA) communication system.

11. A communication system comprising:

means for determining a need to handoff between a first base station and a second base station, wherein the first base station utilizes a wideband system protocol and the second base station utilizes a narrowband system protocol;

means, from a mobile station, for transmitting concurrently, a wideband signal having a predetermined bandwidth and a narrowband signal having a bandwidth within said predetermined bandwidth of said wideband signal, the wideband signal being incompatible with the second base station; and

means, at the second base station, for receiving and processing said narrowband signal for the purposes of handing off the mobile station from the first base station to the second base station.

12. The communication system of claim 11 wherein said means, at said mobile station, for transmitting a wideband signal having a predetermined bandwidth further comprises means, at said mobile station, for transmitting said narrowband signal during communication with a wideband communication system.

13. The communication system of claim 12 wherein said wideband communication system further comprises a code division multiple access (CDMA) communication system.

14. The communication system of claim 11, wherein said narrowband system protocol is used in a narrowband communication system, said narrowband communication system further comprises one of either AMPS or NAMPS.

15. The communication system of claim 11 wherein other mobile stations transmitting a wideband signal having a predetermined bandwidth abstain from transmission during transmission of the narrowband signal by the mobile station.

16. A communication system comprising:

means, from a mobile station, for concurrently transmitting a signal having a predetermined bandwidth and is compatible with a first communication system and transmitting a second signal incompatible with the first communication system, compatible with a second communication system and having a bandwidth within the predetermined bandwidth of the signal compatible with the first communication system; and

means, at the second communication system, for receiving and processing the signal compatible with the second communication system for the purposes of handing off the mobile station.

18. The communication system of claim 16 wherein said means for transmitting a signal compatible with a second communication system and having a bandwidth within the predetermined bandwidth of the signal compatible with the first communication system further comprises means for transmitting a narrowband signal compatible with AMPS or NAMPS and having a narrow bandwidth within the predetermined bandwidth of the signal compatible with the first communication system.

19. The communication system of claim 16 wherein other mobile stations transmitting on the first communication system abstain from transmission during transmission of the narrowband signal by the mobile station.

20. The communication system of claim 16 wherein said means for processing the received signal compatible with a second communication system further comprises means for processing the received signal compatible with a second communication system for purposes of handing off the mobile station from the first communication system to the second communication system.