Apparatus and method for transmitting beacon signals in a communication system

• US 6,078,571 A
• Filed: 09/19/1997
• Issued: 06/20/2000
• Est. Priority Date: 09/19/1997
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Hall, Scott M.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US08/934,362
• Time in Patent Office: 1,005 Days
• Field of Search: 370/320, 370/322, 370/324, 370/329, 370/331, 370/334, 370/335, 370/342, 370/350, 375/200, 455/436, 455/439, 455/440, 455/442, 455/443, 455/456, 455/525
• US Class Current: 370/331
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/36 by user or terminal equipment
• CPC Class Codes: H04W 48/12 using downlink control channel

Abstract

A single transmitter (109) controlled to transmit at appropriate beacon signal frequencies (F1-F3) is scanned through each of the frequencies (F1-F3) so that a mobile station (101) can determine when a hard handoff to different frequencies (F4-F6) is required. The beacon signal transmitter (109) is controlled by a controller (112) to transmit beacon signals which include a pilot channel only, pilot/sync channels, pilot/page/sync channels common to each of the frequencies (F1-F3), or pilot/page/sync channels different for each of the frequencies (F1-F3). Additional control is provided by the controller (112) such that each of frequencies (F1-F3) is further transmitted to different sectors (A1-A3) when the coverage area supported by a target base-station (106) is sectorized.

Claims

1. An apparatus for transmitting a plurality of beacon signals in a wireless communication system, comprising:

a single transmitter adapted to transmit spread spectrum signals and further adapted to transmit the plurality of beacon signals, the beacon signals having a corresponding plurality of different frequencies, the beacon signals utilized primarily to initiate handoff of a mobile station from a first frequency to a second frequency, the transmitter adapted to scan the beacon signal frequencies;

a global positioning system (GPS) timing synchronization block coupled to the transmitter, the GPS timing synchronization block adapted to provide timing information; and

a controller adapted to control the time during which the transmitter transmits the beacon signals at the corresponding plurality of different frequencies.

2. The apparatus of claim 1, wherein the controller is synchronous with the wireless communication system.

3. The apparatus of claim 1, wherein the plurality of beacon signals further comprise a signal having a pilot channel.

4. The apparatus of claim 1, wherein the plurality of beacon signals further comprise a signal having a pilot and synchronization channels.

5. The apparatus of claim 1, wherein the plurality of beacon signals further comprise a signal having a pilot, page and synchronization channels.

6. The apparatus of claim 5, wherein the plurality of beacon signals have common pilot, page and synchronization channels.

7. The apparatus of claim 5, wherein the plurality of beacon signals have different pilot, page and synchronization channels.

8. The apparatus of claim 7, further comprising means for accepting input related to an assignment of the different pilot, page and synchronization channels for each of the plurality of beacon signals.

9. The apparatus of claim 1, wherein the transmitter for transmitting the beacon signals at the corresponding plurality of different frequencies is periodically switched to a different sector of a coverage area.

10. A wireless communication system for handing off a mobile station from a first frequency to a second frequency, the communication system comprising:

at a target coverage area;

means for transmitting a plurality of beacon signals at a corresponding plurality of different frequencies, said means for transmitting adapted to transmit spread spectrum signals and further adapted to scan the beacon signal frequencies;

means, coupled to the means for transmitting, for providing GPS timing information;

means for controlling the time at which the transmitter transmits the beacon signals having the corresponding plurality of different frequencies;

at a mobile station;

means, based on a received one of the beacon signals, for determining that handoff from the first frequency to the second frequency is required and for initiating the handoff;

at a controller;

means for instructing the mobile station to handoff from the first frequency the second frequency based on information related to the initiation of the handoff.

11. The communication system of claim 10, wherein the mobile station communicates with a source base-station via a communication signal having a first frequency from the plurality of different frequencies.

12. The communication system of claim 11, wherein the mobile station initiates the handoff based on a comparison between the communication signal having the first frequency from the plurality of different frequencies and the received one of the beacon signals having the first frequency.

13. The communication system of claim 12, wherein the mobile station initiates the handoff based on a comparison of E_c /I_o between the communication signal having the first frequency from the plurality of different frequencies and the received one of the beacon signals having the first frequency.

14. An apparatus for transmitting a plurality of beacon signals in a wireless communication system, comprising:

a single transmitter adapted to transmit spread spectrum signals and further adapted to transmit the plurality of beacon signals, the beacon signals having a corresponding plurality of different frequencies, the beacon signals utilized primarily to initiate handoff of a mobile station from a first frequency to a second frequency, the transmitter adapted to scan the beacon signal frequencies;

a GPS timing synchronization block coupled to the transmitter, the GPS timing synchronization block adapted to provide timing information; and

a controller adapted to control the transmitter to transmit the beacon signals at times different from one another.

15. A method of transmitting a plurality of beacon signals in a wireless communication system, comprising the steps of:

using a transmitter adapted to transmit spread spectrum signals, transmitting the beacon signals, the beacon signals having a corresponding plurality of different frequencies, the beacon signals utilized primarily to initiate handoff of a mobile station from a first frequency to a second frequency, the transmitter adapted to scan the beacon signal frequencies;

providing GPS timing information to the transmitter; and

controlling the time during which the transmitter transmits the beacon signals at the corresponding plurality of different frequencies.

16. The method of claim 15, wherein the plurality of beacon signals further comprise a signal having a pilot channel or a signal having a pilot and synchronization channels.

17. The method of claim 15, wherein the plurality of beacon signals further comprise a signal having a pilot, page and synchronization channels.

18. The method of claim 17, wherein the plurality of beacon signals have either common pilot, page and synchronization channels or different pilot, page and synchronization channels.

19. The method of claim 18, further comprising the step of accepting input related to an assignment of the different pilot, page and synchronization channels for each of the plurality of beacon signals.

20. The method of claim 15, wherein the step of transmitting the beacon signals at the corresponding plurality of different frequencies is controlled to periodically switch the transmission to a different sector of a coverage area.