HANDOVER BASED ON A QUALITY OF SERVICE METRIC OBTAINED FROM A MAC LAYER OF A RECEIVED SIGNAL

• US 20090154426A1
• Filed: 08/09/2005
• Published: 06/18/2009
• Est. Priority Date: 08/09/2005
• Status: Abandoned Application

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Galmar, Bruno, Perraud, Eric
• Application Number:
  US12/063,422
• Publication Number:
  US 20090154426A1
• Time in Patent Office: Days
• US Class Current: 370/332
• CPC Class Codes: H04W 36/26 by agreed or negotiated communication parameters

Abstract

A wireless communication unit comprises a receiver operably coupled to a signal processing function arranged to make a hand-over determination based on a communication signal received from a serving communication station. The signal processing function is arranged to perform a hand-over operation based on at least one quality of service metric(s) obtained from a medium access control layer of a received signal.

The embodiments comprise identifying an optimal hand-over candidate that enables a more effective hand-over from a first WLAN to a second WLAN or a cellular system.

Claims

1-39. -39. (canceled)

40. A wireless communication unit comprising:

a receiver operably coupled to a signal processing function arranged to make a hand-over determination based on a first communication signal received from a serving communication station and a second communication signal received from one or more candidate serving stations, wherein the signal processing function is arranged to predict whether an available bandwidth provided by the one or more candidate serving stations is sufficient to meet a future communication need of the wireless communication unit and performs a hand-over operation based on at least one quality of service metric(s) obtained from a medium access control (MAC) layer of the first received signal from the current serving communication unit and the predicted available bandwidth provided by the one or more candidate serving stations.

41. A wireless communication unit according to claim 40, wherein the serving communication station is a wireless local area network access point and hand-over is performed from a first WLAN AP to a second WLAN AP or a cellular communication system.

42. A wireless communication unit according to claim 40, further comprising weighting logic operably coupled to the signal processing function arranged to apply a weight to the at least one quality of service metrics according to a measurement associated with the received signal.

43. A wireless communication unit according to claim 40, wherein the signal processing function is arranged such that the prediction of whether the available bandwidth is sufficient is based on one or more of:

(i) The traffic per priority type supported by the serving station; and

(ii) A priority rating of the wireless communication unit or desired service of the wireless communication unit.

44. A wireless communication unit according to claim 40, wherein the signal processing function is arranged such that the predicting the available bandwidth for the wireless communication unit for the candidate serving station incorporates a probability of obtaining access to the channel.

45. A wireless communication unit according to claim 44, wherein the signal processing function is arranged such that the predicting the available bandwidth for the wireless communication unit for the candidate serving station is of the form of a linear equation, where each term of the equation that comprises a value associated with a service provided to the wireless communication unit and a probability of accessing a communication medium supporting a desired traffic type.

46. A wireless communication unit according to claim 45, wherein the signal processing function is arranged such that the predicting the available bandwidth for the wireless communication unit for the candidate serving station combines a percentage of traffic per type of priority and a number that is correlated to a probability of accessing a communication medium for the considered type of traffic relative to a probability of accessing the communication medium for the wireless communication unit'"'"'s service.

47. A wireless communication unit according to claim 45, wherein the signal processing function is arranged such that the predicting the available bandwidth for the wireless communication unit for the candidate serving station is of the form:

48. A wireless communication unit according to claim 40, wherein the at least one quality of service metric(s) comprises a plurality of medium access control layer measurements of the received signal.

49. A wireless communication unit according to claim 40, wherein at least one quality of service metric(s) based on a medium access control (MAC) layer is of the form:

MAC_metrics=a₁*throughput/Max_theo_throughput+a₂*Min_Theo_delay/delay+a₃*jitter*Average_Inter_packet_interval

where ai are application-specific coefficients and define a perceived application quality of service.

50. A wireless communication unit according to claim 40, wherein at least one quality of service metric(s) additionally comprises a physical radio frequency layer measurement of the received signal.

51. A wireless communication unit according to claim 40, wherein the wireless communication unit is arranged to detect a quality of service degradation of a signal transmitted by the serving station based on one or more of the following:

(i) Throughput degradation;

(ii) Downlink packet latency;

(iii) Jitter;

or

(iv) Downlink QoS degradation due to location at a WLAN cell boundary.

52. A wireless communication unit according to claim 40, wherein the signal processing function rates the quality of service metric(s) obtained from a medium access control (MAC) layer with weights depending upon the service being utilized.

53. A wireless communication unit according to claim 40, wherein the signal processing function is arranged such that at least one metric(s) is/are compared to a corresponding at least one adaptive threshold(s) to determine when to perform a hand-over operation.

54. A wireless communication unit according to claim 53 wherein a timer unit is operably coupled to the signal processing function to determine whether one or more of the metric(s) falls below a corresponding at least one adaptive threshold(s) over a period of time.

55. A wireless communication unit according to claim 54 wherein at least one adaptive threshold(s) is updated dynamically depending on a speed of change of the one or more metric.

56. A wireless communication unit according to claim 44 wherein the signal processing function is operably coupled to a memory element for storing records of candidate serving stations in a ranked order according to their predicted available bandwidth.

57. A wireless communication unit according to claim 40, wherein the wireless communication unit performs a hand-over operation in response to a desired level of service by the user of the wireless communication unit.

58. A wireless communication unit according to claim 40, wherein the wireless communication unit is a dual-mode GSM or EDGE or WCDMA /WLAN subscriber phone.

59. A method of handing over communication from a first wireless serving station to a second wireless serving station, the method comprising the step of:

receiving a first communication signal from a serving communication station; and

receiving a second communication signal from one or more candidate serving station;

decoding the first communication signal to identify at least one quality of service metric(s) obtained from a medium access control layer of the received first communication signal;

decoding the one or more second communication signal to predict whether an available bandwidth provided by the one or more candidate serving station is sufficient to meet a future communication need of the wireless communication unit; and

making a hand-over determination based on the predicted available bandwidth provided by the one or more candidate serving station and the at least one quality of service metric(s) obtained from a medium access control layer of the first received signal.