Method and apparatus for dynamically adapting a connection state in a mobile communications system

• US 6,347,091 B1
• Filed: 11/06/1998
• Issued: 02/12/2002
• Est. Priority Date: 06/19/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Rimhagen, Thomas, Wallentin, Bo S. P., Vilander, Harri, Lindskog, Leif P., Hansson, Ulf A., Bark, Per O. G.
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): LOGSDON, JOSEPH B
• Application Number:
  US09/186,702
• Time in Patent Office: 1,194 Days
• Field of Search: 370/229, 370/235, 370/236, 370/238, 370/277, 370/328, 370/329, 370/338, 370/352, 370/353, 370/354, 370/355, 370/437, 370/441, 370/442, 370/443, 370/445, 370/465, 370/466, 370/912, 370/913, 370/431, 709/226, 709/238, 709/239, 709/240
• US Class Current: 370/437
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point

Abstract

In a mobile communications system that provides packet data services, a packet data connection is established between a mobile station and a radio access network. The state of the connection is used to specify one of plural different types of radio channels bearing the connection over the radio interface. The connection state preferably also may specify other parameters including, for example, one of plural different mobility management schemes tailored to the selected channel type or channel bit rate(s). The connection is dynamically adapted to an optimal state based on one or more conditions relating to the connection. For example, one or more traffic parameters are determined for the connection and may be used to predict a future value of that parameter. Based on the predicted parameter value or values, an optimal connection state is determined and implemented. If the predicted parameter value changes later in the connection, another connection state may be dynamically selected that is better suited in accordance with the newly predicted parameter value. One example embodiment is based on the amount of data in queue for a packet data connection. Comparison is made with one or more thresholds to decide which type of radio channel should bear the connection. Other factors, parameters, and conditions may be employed along with threshold comparisons to select the optimal radio channel type.

Claims

1. For use in a communications system supporting a packet data connection with a mobile station over a radio access network, a method comprising:

determining for the packet data connection an amount of packet data to be sent;

comparing the determined amount of packet data to an amount threshold;

if the determined amount of packet data is less than or equal to the amount threshold, determining whether the amount of packet data is increasing or decreasing; and

allocating the packet data connection to a shared type of radio channel configured to support packet data connections with plural mobile stations or a dedicated type of radio channel configured to support a packet data connection with one mobile station based on whether the amount of packet data is increasing or decreasing when the amount of packet data is less than the amount threshold.

2. The method in claim 1, further comprising:

determining time intervals between packets over the packet data connection; and

when the determined time intervals between packets are similar, deciding to assign the packet data connection to the dedicated type of radio channel.

3. The method in claim 1, wherein if the amount of packet data exceeds the amount threshold, the method further comprising:

maintaining the packet data connection on the radio channel currently bearing the packet data connection if data is currently not flowing out of a buffer storing the amount of packet data to be sent.

4. The method in claim 1, further comprising:

if the determined amount of packet data exceeds the amount threshold, the method further comprising;

deciding that the packet data connection should not be transferred to the dedicated type of radio channel if data is currently not flowing out of a buffer storing the amount of packet data to be sent.

5. For use in a communications system supporting a packet data connection with a mobile station over a radio access network, a method comprising:

determining for the packet data connection an amount of packet data to be sent;

comparing the determined amount of packet data to an amount threshold;

if the determined amount of packet data is greater than the amount threshold, considering a flow of packets of the packet data connection in deciding whether to assign a shared type of radio channel configured to support packet data connections with plural mobile stations or a dedicated type of radio channel configured to support a packet data connection with one mobile station, where if the determined amount of packet data is greater than the first amount threshold and if the flow of packets exceeds a flow threshold, the packet data connection is allocated to the dedicated type of radio channel.

6. The method in claim 5, the method further comprising:

if the determined amount of packet data is less than or equal to the first amount threshold and if the amount of packet data is decreasing, allocating the packet data connection to the shared type of radio channel.

7. For use in a communications system supporting a packet data connection with a mobile station over a radio access network, a method comprising the steps of:

determining for the packet data connection an amount of packet data to be sent;

comparing the determined amount of packet data to a first amount threshold;

if the determined amount of packet data is less than the first amount threshold, determining if a back pressure condition exists; and

if a back pressure condition does not exist, selecting a shared type of radio channel that supports plural mobile station connections to bear the packet data connection rather than a dedicated type of radio channel that supports one mobile station connection at a time.

8. The method in claim 7, further comprising:

if a back pressure condition does exist, selecting a dedicated type of radio channel to bear the packet data connection.

9. The method in claim 7, further comprising:

if a back pressure condition does exist, maintaining a current type of radio channel to bear the packet data connection.

10. The method in claim 7, further comprising:

in selecting a radio channel type to bear the packet data connection, performing a channel type selection procedure in addition to the method defined in claim 7.

11. For use in a communications system supporting a packet data connection with a mobile station over a radio access network, a method comprising the steps of:

determining for the packet data connection an amount of buffered packet data to be sent;

comparing the determined amount of packet data to a first buffer amount threshold;

if the determined amount exceeds the first buffer amount threshold, comparing the determined amount of packet data to a second buffer amount threshold; and

establishing the packet data connection on or transferring the packet data connection to one of a dedicated type of radio channel and a shared type of radio channel taking into account the first and second buffer amount threshold comparisons.

12. The method in claim 11, further comprising:

if the determined amount of buffered packet data exceeds the second threshold, establishing the packet data connection on or transferring the packet data connection to a dedicated type of radio channel.

13. The method in claim 11, further comprising:

if the determined amount of buffered packet data exceeds the second threshold, determining if data are not currently being transmit over the packet data connection,

wherein if data are not currently being transmit over the packet data connection maintaining the packet data connection on the type of radio channel currently bearing the packet data connection.

14. The method in claim 13, wherein if data are currently being transmit over the packet data connection, the method further comprising:

selecting a dedicated type of radio channel to bear the packet data connection.

15. The method in claim 11, further comprising:

if the determined amount of packet data is greater than the first buffer amount threshold and less than the second buffer amount threshold, employing hysteresis when selecting the type of radio channel to bear the packet data connection.

16. The method in claim 15, further comprising:

determining whether the determined amount of buffered packet data decreased from being greater than the second buffer amount threshold to being less than the second buffer amount threshold, and if so, selecting a dedicated type of radio channel to bear the packet data connection.

17. The method in claim 16, wherein if determined amount of buffered packet data increased from being less than the first buffer amount threshold to being greater than the first buffer amount threshold, the method further comprising:

selecting a shared type of radio channel to bear the packet data connection.

18. The method in claim 16, wherein if determined amount of buffered packet data increased from being less than the first buffer amount threshold to being greater than the first buffer amount threshold, the method further comprising:

selecting a type of radio channel to bear the packet data connection taking into account another factor in addition to comparing a buffer amount to the first and second buffer amount thresholds.

19. For use in a communications system providing communication with mobile stations by way of a radio access network, apparatus comprising:

a packet buffer for storing packets to be sent over a packet data connection with a mobile station, and

a connection state selector configured to select one of a dedicated type of radio channel and a shared type of radio channel to bear the packet data connection based on an amount of data currently stored in the packet buffer,

wherein a dedicated type of radio channel supports one mobile station connection at a time and a shared type of radio channel supports plural mobile station connections.

20. The apparatus in claim 19, wherein the connection state selector is configured to compare the amount of packet data in the packet buffer to a first threshold and a second threshold greater than the first threshold.

21. The apparatus in claim 20, wherein if the amount of packet data in the packet buffer is less than both the first threshold and the second threshold, the connection state selector is configured to select the shared type of radio channel.

22. The apparatus in claim 20, wherein if the amount of packet data is greater than the first threshold and greater than the second threshold, the connection state selector is configured to maintain the packet data connection on a current type of radio channel.

23. The apparatus in claim 20, wherein if the amount of packet data is greater than the first and second thresholds, the connection state selector is configured to select a dedicated type of radio channel to carry the packet data connection.

24. The apparatus in claim 20, wherein if the amount of packet data in the packet buffer is greater than or equal to the first threshold and less than the second threshold, the connection state selector is configured to determine the type of radio channel taking into account at least one additional parameter.

25. The apparatus in claim 20, wherein if the amount of packet data in the packet buffer is greater than the first threshold and less than the second threshold, the connection state selector is configured to select a dedicated type of radio channel to carry the packet data connection.

26. The apparatus in claim 20, wherein if the amount of packet data in the packet buffer is greater than the first threshold and less than the second threshold, the connection state selector is configured to select a shared type of radio channel to carry the packet data connection.

27. The apparatus in claim 19, further comprising:

a packet store providing packets to the packet buffer,

wherein when an amount of packets currently stored the packet buffer exceeds a predetermined percentage of the packet buffer size, the packet buffer is configured to generate a back pressure signal used to instruct the packet store to temporarily halt transmission of packets to the packet buffer.

28. The apparatus in claim 27, wherein the connection state selector is configured to compare the amount of packet data in the packet buffer to a first threshold, and if the amount of packet data in the packet buffer is less than the first threshold and if the back pressure signal is not present, the connection state selector is configured to select the shared type of radio channel.

29. The apparatus in claim 27, wherein the connection state selector is configured to compare the amount of packet data in the packet buffer to a first threshold, and if the amount of packet data in the packet buffer is less than the first threshold and if the back pressure signal is not present, the connection state selector is configured to determine the radio channel type using an additional parameter relating to packet flow.

30. The apparatus in claim 29, wherein the additional parameter is traffic intensity.

31. The apparatus in claim 29, wherein the additional parameter is time between packet arrivals.

32. The apparatus in claim 29, wherein the connection state controller compares the amount of packet data in the packet buffer to a first threshold, and if the amount of packet data in the packet buffer is less than the first threshold and if the back pressure signal is present, the connection state selector is configured to select the dedicated type of radio channel.

33. The apparatus in claim 19, further comprising:

a protocol window buffer used to monitor packets transmitted from the packet buffer but not yet acknowledged as received, the protocol window buffer configured to generate a full window signal when the number of not yet acknowledged packets exceeds a predetermined threshold.

34. The apparatus in claim 33, wherein if the amount of packet data in the packet buffer is less than a first threshold and if the full window signal is not present, the connection state selector is configured to select the dedicated type of radio channel to bear the packet data connection.

35. The apparatus in claim 33, wherein if the amount of packet data in the packet buffer is less than a first threshold and if the full window signal is present, the connection state selector is configured to maintain the radio channel type currently being used to bear the packet data connection.

36. The apparatus in claim 33, wherein if the amount of packet data in the packet buffer is greater than a first threshold and a second larger threshold, and if the full window signal is present, the connection state selector is configured to maintain a current type of radio channel to bear the packet data connection.

37. The apparatus in claim 19, wherein if the determined amount of packet data is greater than the first threshold and less than the second threshold, the connection state selector is configured to employ hysteresis when selecting the type of radio channel to bear the packet data connection.

38. The apparatus in claim 19, wherein the connection state selector is configured to determine whether the determined amount of packet data decreased from being greater than the second amount threshold, and if so, the connection state selector is configured to select a dedicated type of radio channel to bear the packet data connection.

39. The apparatus in claim 19, wherein the connection state selector is configured to determine whether the amount of packet data increased from being less than the first amount threshold, and if so, the connection state selector is configured to select a shared type of radio channel to bear the packet data connection.

40. The apparatus in claim 19, wherein the connection state controller determines whether the amount of packet data increased from being less than the first amount threshold, and if so, the connection state selector is configured to select a type of radio channel to bear the packet data connection taking into account another factor in addition to comparing the amount of data to the first and second amount thresholds.

41. For use in a Code Division Multiple Access (CDMA) mobile radio communications system providing communication with mobile stations by way of a radio access network, the radio access network supporting one or more of the following connection states including a dedicated connection state that employs a dedicated type of radio channel (DCH), a shared connection state the employs a temporary DCH (TDCH), a shared connection state used by plural mobile terminals at the same time that employs a forward access type of radio channel (FACH) or a random access type of radio channels (RACH), and a shared connection state used by plural mobile terminals at the same time that employs a paging type of radio channel (PACH) or a random access type of radio channels (RACH), apparatus comprising:

a packet buffer for storing packets to be sent over a packet data connection with a mobile station, and

a connection state selector configured to select one of the DCH, TDCH, FACH or RACH, and PACH or RACH connection states to bear the packet data connection based on the amount of data currently stored in the packet buffer.

42. The apparatus in claim 41, wherein connection state selector is configured to select a connection state that employs a FACH or RACH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is below a threshold.

43. The apparatus in claim 41, wherein the connection state selector is configured to select one of the connection states for the packet data connection based on plural ones of the following:

the amount of data currently stored in the packet buffer compared to a buffer threshold, a predicted time to a next packet arrival compared to a time threshold, a detected interference in a cell supporting the packet data connection compared to an interference threshold, and a current connection state for the packet data connection.

44. The apparatus in claim 41, wherein the connector state selector is configured to account for a bearer service associated with the packet data connection when selecting a next connection state.

45. The apparatus in claim 41, wherein each connection state is associated with a mobility management scheme.

46. The apparatus in claim 41, wherein the connection state selector is configured to select a connection state that employs a DCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above a threshold.

47. The apparatus in claim 41, wherein the connection state selector is configured to select a connection state that employs a DCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above buffer threshold and a predicted time to a next packet arrival is below a time threshold.

48. The apparatus in claim 41, wherein the connection state selector is configured to select a connection state that employs a DCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to of above buffer threshold, a predicted time to a next packet arrival is equal to or above a time threshold, and a detected interference in a cell supporting the packet data connection is less than an interference threshold.

49. The apparatus in claim 41, wherein the connection state selector is configured to select a connection state that employs a DCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above buffer threshold, a predicted time to a next packet arrival is equal to or above a time threshold, and an interference associated with a cell supporting the packet data connection is equal to or above an interference threshold.

50. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a FACH or RACH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is below a buffer threshold, a predicted time to a next packet arrival is below a time threshold, and a current connection state bearing the packet data connection employs a FACH or RACH type of radio channel.

51. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a TDCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above buffer threshold and an interference associated with a cell supporting the packet data connection is below an interference threshold.

52. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a TDCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above buffer threshold and an interference associated with a cell supporting the packet data connection is below an interference threshold.

53. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a DCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above buffer threshold, an interference associated with a cell supporting the packet data connection is equal to or above an interference threshold, and a predicted time to a next packet arrival is below a time threshold.

54. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a PCH or RACH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is less than a buffer threshold and a predicted time to a next packet arrival is equal to or above a time threshold.

55. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a DCH type of radio channel to bear the packet data connection if the amount of data currently stored in the packet buffer is equal to or above a buffer threshold, a predicted time to a next packet arrival is equal to or above a time threshold, and an interference associated with a cell supporting the packet data connection is equal to or above an interference threshold.

56. The apparatus in claim 41, wherein the connector state selector is configured to account for a current connection state supporting the packet data connection when selecting a next connection state supporting the packet data connection.

57. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a TDCH type of radio channel to bear the packet data connection if an interference associated with a cell supporting the packet data connection is below an interference threshold and a current connection state bearing the packet data connection employs a TDCH type of radio channel.

58. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a DCH type of radio channel to bear the packet data connection if an interference associated with a cell supporting the packet data connection is equal to or above an interference threshold and a predicted time to a next packet arrival is below a time threshold.

59. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a FACH or RACH type of radio channel to bear the packet data connection if an interference associated with a cell supporting the packet data connection is equal to or above an interference threshold, a predicted time to a next packet arrival is equal to or above a time threshold, and if the amount of data currently stored in the packet buffer is below a buffer threshold.

60. The apparatus in claim 41, wherein the connection state selector is configured to select a next connection state that employs a DCH type of radio channel to bear the packet data connection if an interference associated with a cell supporting the packet data connection is equal to or above an interference threshold, a predicted time to a next packet arrival is equal to or above a time threshold, and if the amount of data currently stored in the packet buffer is above a buffer threshold.