Wireless communication network
The invention relates to a wireless mobile communication system ( 400 ), such as a mobile telephone network. Network configuration data may contain inaccuracies, such as an error in the location of a base station ( 432, 434 ). These inaccuracies may lead to errors in estimating the location of a mobile communication unit ( 410 ). The invention creates probability density functions for the location of a mobile communication unit, based on communications with the mobile communication network ( 430 ). A confidence score may be calculated for each probability density function. A combined function can then be derived from the individual confidence scores. Maximization of the combined function may then lead to a corrected value for a network parameter of the network configuration data. Corrected network configuration data leads to more accurate measurements of the location of mobile communication units. In addition, upgrades to the antennae and base stations can be planned more effectively.
1. A method of correcting network configuration data, the network configuration data describing a wireless communication network in a wireless communication system, the wireless communication system comprising wireless communication units and comprising at least two sectors;
the network configuration data comprising at least one network parameter;
the method comprising:
a) communicating using at least one wireless communication units via wireless communication links with at least two sectors of the wireless communication network;
b) deriving a probability density function for a location of each wireless communication unit communicating in step a), from at least one of the group of:
(i) measurement information from the wireless communication unit;
(ii) the network configuration data;
c) combining the probability density functions from multiple communications to provide a combined function;
d) analyzing the combined function to derive a most likely value for a network parameter, thereby generating a corrected network parameter; and
e) correcting the network configuration data by incorporating the corrected network parameter.
2. A method of correcting network configuration data as in claim 1 , wherein:
step c) comprises calculating a confidence score for each probability density function incorporated in the combined function, and calculating the value of the combined function from the confidence scores; and
step d) comprises varying the network parameter until a maximum value for the combined function has been reached, and selecting the value of the network parameter that maximizes the combined function as the most likely value for the network parameter.
3. A method of correcting network configuration data as in claim 2 , wherein:
step d) includes analyzing the combined function to derive most likely values for two or more network parameters, thereby generating two or more corrected network parameters; and
step e) comprises correcting the network configuration data by incorporating the corrected network parameters.
4. A method of correcting network configuration data as in claim 3 , wherein:
the step of varying the two or more network parameters involves selecting each network parameter of interest in turn, and analyzing how changes to the parameter impact on the combined function.
5. A method of correcting network configuration data as in claim 4 , wherein:
corrected network parameters are generated for the sectors most affected by varying each parameter.
6. A method of correcting network configuration data as in claim 3 , wherein:
the step of varying the two or more network parameters involves varying two or more of the network parameters of interest simultaneously, and analyzing how changes to the parameters impact on the combined function.
7. A method of correcting network configuration data as in claim 3 , further comprising the steps of:
identifying clusters of cells where the confidence scores over an area of interest are unusually low; and
varying the network parameters for those cells.
8. A method of correcting network configuration data as in claim 3 , comprising:
identifying geographical regions in the wireless communication network where rates of dropped calls are higher than either a threshold rate or the mean rate across the network; and
varying the network parameters of cells or sectors to which communications may be made from the geographical regions.
9. A method of correcting network configuration data as in claim 2 , wherein the combined function is the median, the average, or a pre-determined percentile of the confidence scores.
10. A method of correcting network configuration data as in claim 1 , wherein the at least one network parameters are selected from the group of:
antenna or base station location information;
antenna properties;
azimuthal and tilt pointing angles of a sector antenna; and
transmitted power levels.
11. A method of correcting network configuration data as in claim 1 , wherein:
the maximum value of the combined function is found by varying one or more network parameters; and
the one or more network parameters are varied in a direction and/or step size selected by the steepest descent method, Newton's method, simulated annealing, Monte Carlo search, or a genetic algorithm.
12. A method of correcting network configuration data as in claim 1 , wherein:
the probability density function of step b) is derived from at least two individual probability density functions, each individual probability density function being based on either or both of:
the measurement information from the wireless communication unit; or
the network configuration data.
13. A method of correcting network configuration data as in claim 1 , wherein:
the individual probability density functions are created by parametric modeling, using one or more moments of a random variable distribution.
14. A method of correcting network configuration data as in claim 1 , wherein the measurement information from the wireless communication unit comprises at least one from the group of:
one or more absolute distances from the wireless communication unit to one or more network sectors of the wireless communication network;
one or more differential distances between the wireless communication unit and one or more pairs of network sectors of the wireless communication network;
one or more received signal powers recorded by the wireless communication unit from one or more network sectors of the wireless communication network; and
one or more measurements of the received signal-to-noise ratio recorded by the wireless communication unit from one or more network sectors of the wireless communication network.
15. A method of correcting network configuration data as in claim 1 , wherein the method is used in a wireless communication system.
16. A method of correcting network configuration data as in claim 1 , wherein the method is used with a wireless smart-phone.
17. A method of correcting network configuration data as in claim 1 , wherein the method is operable with executable program code executable at least one computer.