Method of transmission in a UMTS mobile telephone network enabling preparation for handover to a GSM cell during a call in a UMTS cell

• US 6,584,116 B1
• Filed: 03/31/1999
• Issued: 06/24/2003
• Est. Priority Date: 04/28/1998
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Gourgue, Frédéric, Roosen, Fabienne
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): HO, CHUONG T
• Application Number:
  US09/282,444
• Time in Patent Office: 1,546 Days
• Field of Search: 370/458, 370/468, 370/442, 370/443, 370/341, 370/345, 370/329, 370/331, 370/332, 370/376, 370/321, 370/330, 370/347, 370/261, 370/431, 370/322, 370/459, 370/528, 370/337
• US Class Current: 370/442
• CPC Class Codes: H04W 36/0094 Definition of hand-off measurement parameters

Abstract

During allocation of time slots of a UMTS frame to a terminal, the UMTS network provides a continuous gap having a duration at least equal to 5 ms in a UMTS frame to enable the receiver of the terminal to measure the power of any GSM signals received and to prepare for possible handover by pre-synchronizing to an adjoining GSM cell.

Claims

1. A method of transmission in a UMTS mobile telephone network enabling preparation for handover to a GSM cell during a call in a UMTS cell, the method comprising transporting information in frames each made up of a plurality of time slots, wherein the time slots from each frame being allocated to mobile telephone terminals for communication via the UMTS mobile telephone network, the method further comprising allocating time slots in each frame to a given mobile telephone terminal in such a manner that, at intervals equal to an integer multiple of the duration of a frame, no time slot is allocated to the given mobile telephone terminal for at least one continuous series of time slots whose total duration is at least equal to a predetermined time period, wherein the continuous series of time slots not allocated to the given mobile telephone terminal is used for reception of a broadcast control channel from the GSM cell and pre-synchronization to the GSM cell.

2. The method claimed in claim 3, further comprising reducing the spectrum spreading of other time slots transporting data in order to increase their transport capacity.

3. The method claimed in claim 1, wherein the predetermined time period is greater than or equal to 5 milliseconds.

4. The method claimed in claim 1, wherein the continuous series of time slots not allocated to the given mobile telephone terminal is included within a single UMTS frame.

5. The method claimed in claim 1, wherein the continuous series of time slots not allocated to the given mobile telephone terminal bridges two adjacent UMTS frames.

6. The method claimed in claim 1, wherein the time slots allocated to the given mobile telephone terminal are used for an uplink burst and a downlink burst within a UMTS frame, and the continuous series of time slots not allocated to the given mobile telephone terminal is interposed between the uplink burst and the downlink burst, and the uplink burst and the downlink burst are separated by at least 5 milliseconds.

7. A mobile telephone terminal that receives information transported in a plurality of UMTS frames, each UMTS frame comprising a plurality of time slots, wherein the mobile telephone terminal prepares to continue a call from a UMTS cell in a GMS cell by:

receiving a series of UMTS frames, wherein each UMTS frame has time slots allocated to the mobile telephone terminal in such a manner that, at intervals equal to an integer multiple of the duration of a UMTS frame, no time slot is allocated to the mobile telephone terminal for at least one continuous series of time slots whose total duration is at least equal to a predetermined time period; and

using the continuous series of time slots not allocated to the mobile telephone terminal to prepare to continue the call in the GSM cell by receiving a broadcast control channel from the GSM cell and pre-synchronizing to the GSM cell.

8. The mobile telephone terminal claimed in claim 7, wherein the predetermined time period is greater than or equal to 5 milliseconds.

9. The UMTS cell claimed in claim 7, wherein the time slots allocated to the mobile telephone terminal by the UMTS cell are used for an uplink burst and a downlink burst within a UMTS frame, the continuous series of unallocated time slots is interposed between the uplink burst and the downlink burst, and the uplink burst and the downlink burst are separated by at least 5 milliseconds.

10. A UMTS cell that transports information in a plurality of UMTS frames, each UMTS frame comprising a plurality of time slots, wherein the UMTS cell allows a mobile telephone terminal to prepare to continue a call from the UMTS cell in a GMS cell by:

allocating at least a portion of the time slots in each of the UMTS frames to the mobile telephone terminal in such a manner that, at intervals equal to an integer multiple of the duration of a UMTS frame, no time slot is allocated to the mobile telephone terminal for at least one continuous series of time slots whose total duration is at least equal to a predetermined time period, wherein the continuous series of time slots not allocated to the mobile telephone terminal is used for reception of a broadcast control channel from the GSM cell and pre-synchronization to the GSM cell; and

transmitting the UMTS frames to the mobile telephone terminal.

11. The UMTS cell claimed in claim 10, wherein the UMTS cell, while allocating time slots to the mobile telephone terminal, reduces the spectrum spreading of other time slots transporting data in order to increase their transport capacity.

12. The UMTS cell claimed in claim 10, wherein UTMS cell sets the predetermined time period to greater than or equal to 5 milliseconds.

13. The UMTS cell claimed in claim 10, wherein the continuous series of time slots not allocated to the mobile telephone terminal by the UMTS cell is within a UMTS frame.

14. The UMTS cell claimed in claim 10, wherein the continuous series of time slots not allocated to the mobile telephone terminal by the UMTS cell bridges two adjacent UMTS frames.

15. A UMTS mobile telephone network including at least one UMTS cell and at least one mobile telephone terminal, wherein information is transported between UMTS cell and the mobile telephone terminal in a plurality of UMTS frames, each UMTS frame comprising a plurality of time slots, the network prepares to handover a call from the UMTS cell to a GMS cell by:

allocating time slots to a given mobile telephone terminal in such a manner that, at intervals equal to an integer multiple of the duration of a UMTS frame, no time slot in each of the UMTS frames is allocated by the UMTS cell to the mobile telephone terminal for at least one continuous series of time slots whose total duration is at least equal to a predetermined time period;

transmitting the UMTS frames containing the allocated time slots to the mobile telephone terminal; and

preparing to continue the call in the GSM cell, wherein the mobile telephone terminal uses the unallocated continuous series of time slots to receive a broadcast control channel from the GSM cell and to pre-synchronize to the GSM cell to prepare for handover to the GSM cell.

16. The UMTS mobile telephone network claimed in claim 15, wherein the UMTS cell reduces, during the allocation allocating the time slots, the spectrum spreading of other time slots transporting data in order to increase their transport capacity.

17. The UMTS mobile telephone network claimed in claim 15, wherein the UMTS cell sets the predetermined time period greater than or equal to 5 milliseconds.

18. The UMTS mobile telephone network method claimed in claim 15, wherein the continuous series of time slots not allocated to the mobile telephone terminal by the UMTS cell is within a UMTS frame.

19. The UMTS mobile telephone network claimed in claim 15, wherein the continuous series of time slots not allocated to the mobile telephone terminal by the UMTS cell allocates the time slots bridges two adjacent UMTS frames.

20. The UMTS mobile telephone network claimed in claim 15, wherein the time slots allocated to the mobile telephone terminal by the UMTS cell are used for an uplink burst and a downlink burst within a UMTS frame, the continuous series of unallocated time slots is interposed between the uplink burst and the downlink burst, and the uplink burst and the downlink burst are separated by at least 5 milliseconds.

21. A method of transmission in a UMTS mobile telephone network, wherein information is transported in a plurality of UMTS frames, the UMTS frames being allocated to mobile telephone terminals for communication via the UMTS mobile telephone network such that a series of UMTS frames is equal to the time duration of a GMS multiframe and the time duration of individual UMTS frames is equal to a predetermined time period, the method further comprises:

allocating, at intervals equal to an integer multiple of the duration of a UMTS frame, all but a portion of one UTMS frame within the series of UMTS frames to the mobile telephone terminals; and

using the unallocated UMTS frame portion to prepare to handover a call from a UMTS cell to a GSM cell for reception of a broadcast control channel from the GSM cell and pre-synchronization to the GSM cell.

22. The method claimed in claim 21, wherein the predetermined time period of each of the UMTS frames is greater than or equal to 5 milliseconds.

24. A mobile telephone terminal that receives information transported in a series of UMTS frames that are equal in duration to a GMS multiframe, the UMTS frames being allocated to mobile telephone terminals for communication via the UMTS mobile telephone network such that a series of UMTS frames is equal to the time duration of a GMS multiframe and the time duration of individual UMTS frames is equal to a predetermined time period, wherein the given mobile telephone terminal prepares to continue a call from a UMTS cell in a GMS cell by:

receiving a series of UMTS frames, wherein at least a portion of a single UMTS frame in the series of UMTS frames is not allocated to the mobile telephone terminal; and

using the portion of the single UMTS frame not allocated to the given mobile telephone terminal to prepare to continue the call in the GSM cell, wherein the given mobile telephone terminal uses the portion of the single UMTS frame not allocated to the given mobile telephone terminal to receive a broadcast control channel from the GSM cell and to pre-synchronize to the GSM cell.

23. The method claimed in claim 24, wherein, in the allocation of the UMTS frames, the entirety of the single UMTS frame that is not allocated to the mobile telephone terminals is used for GSM broadcast control channel reception and pre-synchronization.

25. The mobile telephone terminal claimed in claim 24, wherein the predetermined time period of a UMTS frame is greater than or equal to 5 milliseconds.

26. A UMTS cell that transports information in a plurality of UMTS frames, the UMTS frames being allocated to mobile telephone terminals for communication via the UMTS mobile telephone network such that a series of UMTS frames is equal to the time duration of a GMS multiframe and the time duration of individual UMTS frames is equal to a predetermined time period, the UMTS cell allowing mobile telephone terminals to prepare to continue a call from the UMTS cell in a GMS cell by:

allocating, at intervals equal to an integer multiple of the duration of a UMTS frame, all but a portion of one UTMS frame within the series of UMTS frames to the mobile telephone terminals, wherein the continuous series of time slots not allocated to the mobile telephone terminals is used for reception of a broadcast control channel from the GSM cell and pre-synchronization to the GSM cell; and

transmitting the series of UMTS frames to the mobile telephone terminals.

27. The UMTS cell claimed in claim 26, wherein the UMTS cell sets the predetermined time period of each UMTS frame to greater than or equal to 5 milliseconds.

28. The UMTS cell claimed in claim 26, wherein the frame portion of the UMTS frame not allocated to the mobile telephone terminals is the entirety of the frame.

29. A UMTS mobile telephone network including at least one UMTS cell and at least one mobile telephone terminal, wherein information is transported in a plurality of UMTS frames, the UMTS frames being allocated to mobile telephone terminals for communication via the UMTS mobile telephone network such that a series of UMTS frames is equal to the time duration of a GMS multiframe and the time duration of individual UMTS frames is equal to a predetermined time period, the network prepares to handover a call from the UMTS cell to a GSM cell by:

allocating, at intervals equal to an integer multiple of the duration of a UMTS frame, all but a portion of a single UMTS frame within the series of UMTS frames to the mobile telephone terminals for communication; and

using the frame portion not allocated to the mobile telephone terminals to prepare to continue a call from the UMTS cell in the GSM cell, wherein the mobile telephone terminals use the frame portion not allocated to the mobile telephone terminals to receive a broadcast control channel from the GSM cell and to pre-synchronize to the GSM cell.

30. The UMTS mobile telephone network claimed in claim 29, wherein the network sets the predetermined time period of each UMTS frame to greater than or equal to 5 milliseconds.

31. The method claimed in claim 29, wherein, in the allocation of the UMTS frames, the portion of the UMTS frame not allocated to the mobile telephone terminals comprises the entirety of the UMTS frame.