Paging channel control method and apparatus

• US 6,600,757 B1
• Filed: 12/03/1997
• Issued: 07/29/2003
• Est. Priority Date: 12/03/1996
• Status: Expired due to Term

• Current Assignee: Inmarsat Global Limited (Inmarsat PLC)
• Original Assignee: International Mobile Satellite Organization
• Inventors: Jones, Edward Arthur, Petri, Gerhard
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Phunkulh, Bob A.
• Application Number:
  US08/984,325
• Time in Patent Office: 2,064 Days
• Field of Search: 370/328, 370/329, 370/330, 370/331, 370/336, 370/337, 370/345, 370/347, 370/350, 370/436, 370/437, 370/468, 455/422, 455/426, 455/427, 455/434, 455/436, 455/450, 455/437, 455/438
• US Class Current: 370/480
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 84/022 One-way selective calling networks, e.g. wide area paging
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a messaging system, message traffic is transmitted on one or more traffic channels T₁, T₂ and the allocation of groups S₁, S₂ of receivers to the traffic channels T₁, T₂ is controlled by information transmitted on a bulletin board channel BB. A predetermined number of frames before a change in the traffic channel allocation, a countdown value is transmitted in the relevant traffic channel T₁ and the countdown value is decremented in each subsequent frame. Before the countdown value reaches zero, the groups of receivers S₁, S₂ retune to the bulletin board channel, receive their new channel allocations and retune to the traffic channel indicated for their group. The frame timings of the different traffic channels T₁, T₂ are staggered to reduce the peak power required to transmit message bursts in these channels.

Claims

1. A method of controlling a channel allocation of a receiver, comprising:

controlling a transmission of a control channel indicating a current channel allocation of the receiver;

whereby the current channel allocation is modified from a first traffic channel to a second traffic channel;

controlling a transmission of the first traffic channel allocated to the receiver such that a channel change indication is transmitted over the first traffic channel to the receiver and the receiver is caused to receive said control channel so as to receive an indication of said modified allocation to the second traffic channel.

2. A method as claimed in claim 1, wherein the channel change indication is transmitted more than once before the receiver is required to receive said control channel.

3. A method as claimed in claim 2, wherein each of said channel change indications indicates when the current channel allocation of the receiver will be modified.

4. A method as claimed in any one claims 1 to 3, wherein said first traffic channel has a repeating frame structure, the channel change indications each being transmitted in a respective frame and indicating the number of frames remaining before the current channel allocation will be modified.

5. A method as claimed in any one of claims 1 to 3, whereby the receiver is caused to receive said second traffic channel after receiving said control channel with a timing determined by said channel change indication.

6. Apparatus for controlling a channel allocation of a receiver, comprising:

means for controlling a transmission of a control channel indicating a current channel allocation of the receiver, whereby the current channel allocation is modified from a first traffic channel to a second traffic channel; and

means for controlling a transmission of the first traffic channel allocated to the receiver such that a channel change indication is transmitted over the first traffic channel to the receiver and the receiver is caused to receive said control channel so as to receive said indication of said modified allocation to the second traffic channel.

7. Apparatus as claimed in claim 6, wherein the means for controlling the transmission of the first traffic channel is arranged so that the channel change indication is transmitted more than once before the receiver is required to receive said control channel.

8. Apparatus as claimed in claim 7, wherein the means for controlling the transmission of the first traffic channel is arranged so that each of said channel change indications indicates when the channel allocation of the receiver will be modified.

9. Apparatus as claimed in claim 6 or 7, wherein said means for controlling the transmission of the first traffic channel is arranged so that the first traffic channel has a repeating flame structure, the channel change indications being each transmitted in a respective frame and indicating a number of frames remaining before the current channel allocation will be modified.

10. A method of changing channel reception in a receiver, comprising:

receiving a first traffic channel;

detecting in said first traffic channel a channel change indication;

receiving a control channel in response to said channel change indication;

detecting a channel indication relating to the receiver in said control channel; and

receiving a second traffic channel designated by said channel indication.

11. A method as claimed in claim 10, wherein the receiver begins to receive said second traffic channel at a time indicated by said channel change indication.

12. A method as claimed in claim 10 or 11, wherein the receiver begins to receive the control channel at a time indicated by said channel change indication, before receiving the second traffic channel.

13. A method as claimed in any one of claims 10 to 11, wherein the control channel includes a plurality of channel indications and a plurality of receiver indications, and the receiver receives the second traffic channel indicated by one of the channel indications corresponding to one of the receiver indications which corresponds to said receiver.

14. A receiver, comprising:

means for controlling the receiver to receive a first traffic channel;

means for detecting in said first traffic channel a channel change indication;

means for controlling the receiver to receive a control channel in response to said channel change indication;

means for detecting a channel indication relating to the receiver in said control channel; and

means for controlling the receiver to receive a second traffic channel designated by said channel indication.

15. A receiver as claimed in claim 14, wherein the means for controlling the receiver to receive the second traffic channel is arranged so that the receiver begins to receive said traffic channel at a time indicated by said channel change indication.

16. A receiver as claimed in claim 14 or 15, wherein the means for controlling the receiver to receive the control channel is arranged so that the receiver begins to receive the control channel at a time indicated by said channel change indication, before receiving the second traffic channel.

17. A receiver as claimed in any one of claims 14 to 15, wherein the control channel includes a plurality of channel indications and a plurality of receiver indications, and the means for controlling the receiver to receive the second traffic channel is arranged so that the receiver receives the second traffic channel indicated by one of the channel indications corresponding to one of the receiver indications corresponding to said receiver.

18. A receiver as claimed in any one of claims 14 to 15, arranged to receive only one channel at any one time.

19. A receiver as claimed in any one of claims 14 to 15, wherein the receiver is included in a message terminal.

20. An apparatus for controlling a transmission of a plurality of frequency channels, each of which has a frame format of substantially a same constant frame period, comprising:

a traffic channel controller to control a timing of transmission of said frequency channels such that a start timing of a plurality of frames of each of said frequency channels differs from that of other ones of said frequency channels; and

a control channel controller to control a transmission of a control channel including a plurality of sets of channel control data each relating to a corresponding one of said plurality of frequency channels such that said sets are transmitted sequentially and an order of starting of said frames of said frequency channels substantially corresponds to an order of transmission of said sets of said channel control data.

21. An apparatus for controlling a channel allocation of a receiver, comprising:

a control channel controller to control a transmission of a control channel indicating a current channel allocation of the receiver, whereby the current channel allocation is modified from a first traffic channel to a second traffic channel; and

a traffic channel controller to control a transmission of the first traffic channel allocated to the receiver such that a channel change indication is transmitted to the receiver and the receiver is caused to receive said control channel so as to receive said indication of said modified allocation to the second traffic channel.

22. The apparatus as claimed in claim 21, wherein the traffic channel controller is arranged so that the channel change indication is transmitted more than once before the receiver is required to receive said control channel.

23. The apparatus as claimed in claim 22, wherein the traffic channel controller is arranged so that each of said channel change indications indicates when the channel allocation of the receiver will be modified.

24. The apparatus as claimed in claim 22 or 23, wherein said traffic channel controller is arranged so that the first traffic channel has a repeating frame structure, the channel change indications being each transmitted in a respective frame and indicating a number of frames remaining before the current channel allocation will be modified.

25. A receiver, comprising:

a controller to control the receiver to receive a first traffic channel;

a detector to detect in said first traffic channel a channel change indication, wherein;

said controller is further for controlling the receiver to receive a control channel in response to said detected channel change indication;

said detector is further for detecting a channel indication relating to the receiver in said control channel; and

said controller is further for controlling the receiver to receive a second traffic channel designated by said channel indication.

26. The receiver of claim 25, wherein said controller is arranged to cause said receiver to begin to receive said second traffic channel at a time indicated by said channel change indication.

27. The receiver as claimed in claim 25 or 26, wherein the controller is arranged to control the receiver to receive the control channel so that the receiver begins to receive the control channel at a time indicated by said channel change indication, before receiving the second traffic channel.

28. The receiver as claimed in any one of claims 25 to 26, wherein the control channel includes a plurality of channel indications and a plurality of receiver indications, and the controller is arranged to control the receiver to receive the second traffic channel so that the receiver receives the second traffic channel indicated by one of the indications corresponding to one of the receiver indications corresponding to said receiver.

29. The receiver as claimed in any one of claims 25 to 26, arranged to receive only one channel at any one time.

30. The receiver as claimed in any one of claims 25 to 26, wherein the receiver is included in a message terminal.