Communications system and a method therefor

• US 6,122,270 A
• Filed: 10/16/1997
• Issued: 09/19/2000
• Est. Priority Date: 01/28/1995
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Robinson, William Neil, Gibbs, Joanthan Alastair, Whinnett, Nicholas William
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Previl, Daniel
• Application Number:
  US08/875,319
• Time in Patent Office: 1,069 Days
• Field of Search: 370/252, 370/331, 370/332, 370/333, 370/335, 370/337, 370/342, 370/350, 370/465, 370/468, 370/477, 370/521, 370/503, 370/347, 455/436, 455/442
• US Class Current: 370/342
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone

Abstract

An apparatus and method enabling a mobile station to transfer its communications between two dissimilar communications systems, for example, between a first communications system having a time continuous structure, such as a CDMA system, and an alternate communications system having a time discontinuous structure, such as a TDMA system. In one embodiment, the mobile station initiates a time-compressed mode of operation of the first system in which, for a portion of each frame, transmission is disabled, accesses the second system during the disabled periods and specifies to the first system frame structure information of the second system. The first system adjusts the time-compressed mode of operation so that communication with the mobile station occurs during `N` time slots of each frame, the widths and positions of each slot within each frame being set in order to avoid contention with communications to and from the second system.

Claims

1. A communications apparatus comprising a first communications system having a time continuous frame structure and a mobile station for communication therewith, wherein the mobile station is able to communicate with a second communication system having a time discontinuous frame structure, the apparatus further including:

means in the mobile station for initiating a time compressed mode of operation of the first system in which for a portion of each frame, transmission is disabled;

means in the mobile station for accessing, during the disabled periods, the second system;

means in the mobile station for specifying to the first system frame structure information of the second system; and

means in the first system for adjusting the time-compressed mode of operation so that communication with the mobile station occurs during `N` time slots of each frame, the width and position of each slot within each frame being set in order to avoid contention with communications to and from the second system.

2. The communications apparatus of claim 1 wherein the first system is a CDMA system and the second system is a TDMA system.

3. The communications apparatus of claim 1 wherein the frame structure information includes a position of the first downlink slot of the second system in the relation to the frame structure of the first system.

4. The communications apparatus of claim 1 wherein the mobile station includes means for informing the first system of the number of time slots `N` per frame during which communications will occur.

5. The communications apparatus of claim 1 further comprising means for processing the `N` highest energy received time-slots.

6. The communications apparatus of claim 1 further comprising means for arranging adjustment of power transmitted by the mobile station and the first system, by the mobile station, to a power level inversely proportional to `N`.

7. A method of facilitating handing-off a mobile station between a first communications system having a time continuous frame structure and a second communications system having a time discontinuous frame structure, the method comprising the steps of:

initiating a time compressed mode of operation of the first system by the mobile station in which for a portion of each frame, transmission is disabled;

accessing in the mobile station during the disabled periods, the second system;

specifying to the first system by the mobile station, frame structure information of the second system; and

adjusting in the first system, the time-compressed mode of operation so that communication with the mobile station occurs during `N` time slots of each frame, the widths and position of each slot within each frame being set in order to avoid contention with communications to and from the second system.

8. The method of claim 7 including the further step of by the mobile station informing the first system of the number of time slots `N` per frame during which communications will occur.

9. The method of claim 7 wherein the first system is a CDMA system and the second system is a TDMA system.

10. The method of claim 7 wherein the frame structure information includes a position of the first downlink slot of the second system in the relation to the frame structure of the first system.

11. The method of claim 7 further comprising processing the `N` highest energy received time slots.

12. The method of claim 7 further comprising arranging adjustment of power transmitted by the mobile station and the first system, by the mobile station, to a power level inversely proportional to `N`.

13. A communications apparatus comprising a first communications system having a time continuous frame structure and a mobile station for communication therewith, wherein the mobile station is able to communicate with a second communication system having a time discontinuous frame structure, the apparatus further including:

a time compressed operation mode initiator in the mobile station operable to initiate a time compressed mode of operation of the first system in which for a portion of each frame, transmission is disabled;

an access unit in the mobile station operable to access, during the disabled periods, the second system;

a frame structure information unit in the mobile station operable to specify to the first system frame structure information of the second system; and

an adjuster in the first system operable to adjust the time-compressed mode of operation so that communication with the mobile station occurs during `N` time slots of each frame, the width and position of each slot within each frame being set in order to avoid contention with communications to and from the second system.

14. The communications apparatus of claim 13 wherein the first system is a CDMA system and the second system is a TDMA system.

15. The communications apparatus of claim 13 wherein the frame structure information includes a position of the first downlink slot of the second system in the relation to the frame structure of the first system.

16. The communications apparatus of claim 13 further including a time slot information unit in the mobile station operable to inform the first system of the number of time slots `N` per frame during which communications will occur.

17. The communications apparatus of claim 13 further comprising a processor operable to process the `N` highest energy received time-slots.

18. The communications apparatus of claim 13 further comprising a power level adjuster operable to arrange adjustment of power transmitted by the mobile station and the first system, by the mobile station, to a power level inversely proportional to `N`.