Telecommunications – Radiotelephone system – Security or fraud prevention
Utility Patent
1997-11-22
2001-01-02
Le, Thanh Cong (Department: 2749)
Telecommunications
Radiotelephone system
Security or fraud prevention
C455S435100, C455S560000
Utility Patent
active
06169892
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to wireless communications systems, and more particularly, to a method of performing authentication of a mobile station to ensure that a mobile station is a valid user and reducing the number of authentication triplet requests during busy periods.
BACKGROUND OF THE INVENTION
Authentication is the process by which a mobile switching center (MSC) ensures that the mobile subscriber is really a valid user. In order to authenticate the mobile subscriber, a set of authentication triplets is required from a home location register HLR. Conventionally, the MSC uses one of these sets of authentication triplets each time the mobile subscriber is authenticated, and then throws away this triplet (GSM specification recommendation).
Referring to
FIG. 1
, there is shown a conventional wireless communication system
10
, which may be a GSM, TDMA, CDMA etc. technology. The gateway MSC
12
communicates calls between a public switched communication network (PSTN)
14
and a plurality of base switching center (BSCs)
16
. The BSCs
16
in turn, service the mobile subscribers (MSs)
18
via RF radio signals. Each MSC
12
has a visitors location register (VLR)
22
for storing currently served MS
18
information. The amount of work the MSC
12
spends on requesting authentication triplets from the home location register of the serviced mobile subscribers (HLR)
20
is significant. Moreover, the amount of work the HLR
20
spends generating these authentication triplets is higher than the work done by the MSC
12
. As the overall traffic level e.g. calls and mobility events at a MSC increases, the amount of Authentication increases.
In the past, to increase the capacity of the MSC
12
, many different mechanisms have been used. These include hardware upgrades to faster processors, software optimizations, and the reduction of the amount of work required to be done by the MSC
12
e.g. by reducing messaging for inter-VLR location updates such as disclosed in commonly assigned U.S. patent application Ser. No. 08/864,927, entitled “Distributed Subscriber Data Management in Wireless Network” filed May 29, 1997, and U.S. patent application Ser. No. 08/864,926, entitled “Distributed Subscriber Data Management in Wireless Networks from a Central Perspective” filed May 29, 1997, the teachings of which are included herein by reference.
Authentication can occur on the following events: call originations, call terminations, inter-VLR location updates, intra-VLR location updates, and periodic location updates. The frequency of authentication is specified via an operator controlled parameter (except for inter-VLR location updates, which must always be authenticated). Presently, the MSC/VLR can store N authentication triplets per mobile subscriber. “The concept of using authentication triplets is known in the art, and defined by EIA standards.” One triplet is used each time an authentication event occurs. The rate that authentication triplets are requested from the HLR is in direct proportion to the number of events that are occurring on the MSC.
In a mobile switch the amount of processor time used is in direct proportion to the number of subscribers, the amount of mobility for each subscriber, and the number of calls processed. As more subscribers move around, and more calls are made, the MSC uses greater and greater percentage of its available CPU processing power. For example, since there are more calls made and more subscribers moving around at 5:00 PM than at 5:00 AM, the available CPU processing power at 5:00 PM is less than at 5:00 AM. Typical traffic peaks and valleys are illustrated in FIG.
3
and FIG.
4
. The MSC should be engineered to support the maximum daily traffic period.
Currently, the MSC/VLR can store N authentication triplets per subscriber. One triplet is used each time an authentication event occurs. When an authentication event has been completed, the MSCIVLR checks to see how many triplets are left for that subscriber. If there are X number of triplets left, the MSC requests more triplets from the HLR of that subscriber. A typical setting on a MSC is N=7 and X=2. As can be seen in
FIG. 5
, the rate that Authentication triplets are requested is in direct proportion to the traffic level at the MSC (The traffic level at the MSC changes based on the time of day).
There is a desire for an improved method to reduce the number of requests to the HLR for Authentication triplets during busy periods in a wireless communications network to achieve a capacity increase on the MSC and a capacity increase on the HLR. This would increase the number of subscribers that may be supported by each MSC during busy periods.
SUMMARY OF THE INVENTION
The present invention achieves technical advantages as a method of dynamically adjusting when authentication triplets are requested from a authentication triplet source as a function of how busy the MSC is, particularly, as a function of the percentage of CPU usage time that is currently being used by the MSC. This is done by dynamically setting the authentication triplet request threshold when a new set of triplets is requested. During less busy times e.g., the MSC may request, for instance, a new set of 5 triplets from the HLR when only 4 triplets remain (X is set to equal 4), thus wasting 2 triplets. During medium busy periods, the MSC may request a new set of 5 triplets when only 2 triplets remain (X=2), thus filling up the subscriber authorization list to 7 triplets. During very busy times, the MSC may request a new set of 5 triplets when 0 triplets remain (X=0) at the MSC for the subscriber period.
The present invention achieves technical advantages by reducing the work done by the MSC to request authentication triplets during busy hours and increasing the work done to request authentication triplets during non busy periods, to increase the overall efficiency of the MSC, especially during busy times. The MSC dynamically determines when a new set of authentication triplets will be requested from the HLR as a function of the percentage of CPU time currently being used. As an example, when less than 20% of the CPU is being used, X=4, when between 20% and 70% of the CPU is used X=2, and when greater than 70% of the CPU is used X=0. N=7 in all cases. There is no penalty for doing extra work in non-busy periods since the MSC and HLR are engineered for busy periods. The MSC dynamically ascertains how busy the MSC CPU is e.g. using the call processing occupancy (CPOCC) data field at the MSC to determine the percentage of CPU time that is currently being used.
REFERENCES:
patent: 5097499 (1992-03-01), Cosentino
patent: 5101451 (1992-03-01), Ash et al.
patent: 5454026 (1995-09-01), Tanaka
patent: 5537474 (1996-07-01), Brown et al.
patent: 5548533 (1996-08-01), Gao et al.
patent: 5708710 (1998-01-01), Duda
patent: 5790955 (1998-08-01), Tomoike
patent: 5835490 (1998-11-01), Park et al.
patent: 5862481 (1999-01-01), Kulkarni et al.
patent: 5867787 (1999-02-01), Vudali et al.
patent: 6014558 (2000-01-01), Thomas
patent: 6064892 (2000-05-01), Miyagawa et al.
Chow Charles
Cong Le Thanh
Crane John D.
Northern Telecom Limited
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