Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-11-13
2001-06-12
Kincaid, Lester G. (Department: 2682)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S422100, C455S450000, C455S067150
Reexamination Certificate
active
06246880
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates in general to the telecommunications field, and in particular, to a method and system for (i) determining or estimating present traffic levels and for predicting future traffic levels in wireless communications systems and (ii) optionally increasing the resources thereof in response to the ascertained traffic levels.
2. Description of Related Art
Wireless communication enables subscribers to place and receive calls from various locations. The increased safety, productivity, and convenience of wireless communication has led to explosive growth across most wireless networks. Meeting the demands of this explosive growth can be difficult and costly. The wireless system is planned well in advance of deployment and is subsequently periodically updated and expanded according to subscriber demands.
Responses to busy traffic levels and growth can include splitting one cell with one base station (BS) into two cells with two BSs. It can also include increasing the resources within a given BS so that the given BS may simultaneously service more subscribers. If expansion of the wireless network fails to precede demand, then potential revenue can be forfeited and, perhaps, relationships with customers may be permanently injured. If, on the other hand, expansion unnecessarily outgrows demand, then capital may be squandered because equipment is prematurely installed and consequently underutilized.
It would therefore be beneficial (e.g., short- and long-term income-maximizing) if wireless service providers could expand their networks concomitantly with busy traffic levels and the predicted growth demands of subscribers. It would be especially advantageous if wireless service providers could expand their networks such that their ability to provide wireless services increases in accordance with increases in busy traffic levels, and just prior to subscriber growth that will consume their expanded ability. Unfortunately, such well-timed expansion usually requires that busy hour traffic levels be ascertained and that subscriber growth be accurately predicted for both an entire wireless communications network and for its individual cells.
In order to predict a future traffic level, conventional techniques employ a simple linear model based on the recorded traffic data in the relevant market. This model is inadequate for meeting the requirements of the operator because it is very difficult to estimate the possible growth function on individual cells. In other words, the forecasting of future traffic levels is inaccurate due to the use of an insufficiently complex mathematical model.
In summary, conventional wireless communications systems have heretofore inadequately accounted for subscriber requirements during peak access periods, and inaccurately predicted future traffic growth. Consequently, wireless service providers have been unable to optimally provide resources to meet subscriber demands.
SUMMARY OF THE INVENTION
The method and system of the present invention optimizes resource allocation within a wireless communications system. The wireless communications system includes an area divided into cells, BSs, at least one mobile services switching center (MSC), and multiple mobile stations (MSs). Some resources in the wireless communications system may be added (e.g., scaled) as subscriber demands grow. These resources may be, for example, associated with the BSs on a cell level or associated with the MSC on a multi-cell level (e.g., based on an amalgamation of subscriber demands among MSC-connected cells). An exemplary resource that may be properly dimensioned using the principles of the present invention is the transceiver (TRX).
In an exemplary embodiment of the present invention, one TRX is assigned per currently-connected subscriber. Accordingly, one TRX is optimally present for each subscriber that requests access to a particular BS, or at least as required to achieve an operator-desired grade of service. In one aspect of the present invention, the number of subscribers that are attempting to access the wireless communications system is estimated based, at least in part, on (i) an average traffic load or level (TL), (ii) the number of access requests that are denied, and/or (iii) empirical evidence.
According to another aspect of the present invention, a future traffic level is predicted using a growth equation and statistical observations. In a first method, a simple exponential growth model is applied to observations, each of which may include a time of entry and a corresponding TL. In a second method, a non-linear optimization model is applied to multiple observations in which each observation entry may include a time of entry, a mean TL, a busy hour TL, and a number of TRXs. At least three such observed entries are preferably incorporated into the unique solution of the growth equation for each given cell in question. The principle of least squares and an iterative Newton-Rapson process is applied to the unique solution after incorporation of the observed entries. Three vital coefficients of the growth equation are thereby determined. The growth equation may then be used to predict future traffic levels at selected times.
According to yet another aspect of the present invention, resources are optimally allocated in response to the estimated congested TLs and the predicted future TLs. Thus, TRXs may be dimensioned within a given cell so that congested TLs are accommodated. Also, TRXs may be dimensioned (prior to actual subscriber demand) so that future TLs may be accommodated before subscriber growth causes any congestion.
An important technical advantage of the present invention is that it enables an estimation of a possible traffic level during periods of congestion when all traffic channels are already assigned.
Another important technical advantage of the present invention is that it provides a formulated approach to predicting future traffic levels at the cell level of a wireless communications system.
Yet another important technical advantage of the present invention is the ability to improve radio frequency planning based on the forecasted traffic levels.
Yet another important technical advantage of the present invention is the ability to optimally utilize network resources based on historical traffic data.
The above-described and other features of the present invention are explained in detail hereinafter with reference to the illustrative examples shown in the accompanying drawings. Those skilled in the art will appreciate that the described embodiments are provided for purposes of illustration and understanding and that numerous equivalent embodiments are contemplated herein.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the method and apparatus of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein:
FIG. 1
illustrates ten cells within a wireless communications system of a type in which the present invention may be practiced;
FIG. 2
illustrates an enlarged, more-detailed view of certain portions of the wireless communications system of
FIG. 1
;
FIG. 3
illustrates a method in flowchart form for determining various traffic level data, including a congested traffic level;
FIG. 4
illustrates a data memory structure of determined traffic level values;
FIG. 5
illustrates a method in flowchart form for predicting future traffic levels;
FIG. 6
illustrates a method in flowchart form for accommodating subscriber demands with appropriate resource dimensioning;
FIG. 7
illustrates in graphical form an exemplary implementation of the estimation of future traffic levels to further illuminate certain principals of the present invention; and
FIG. 8
illustrates another method in flowchart form for accommodating subscriber demands with appropriate resource dimensioning.
REFERENCES:
patent: 5475868 (1995-12-01), Duque-Anton et al.
patent: 5507007 (1996-04-01), Gunmar et al.
patent
Jenkens & Gilchrist a Professional Corporation
Kincaid Lester G.
Telefonaktiebolaget LM Ericsson (publ)
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