This invention relates to wireless communications, and more specifically to a method and apparatus for providing automatic network performance data collection and optimization.
Wireless communication networks such as cellular telephone systems typically require periodic “drive testing” in order to perform radio frequency (RF) performance optimization of the network. Drive testing typically encompasses a team of technicians who drive around the cellular system geographical coverage area testing the RF coverage and other parameters of the system. The technicians usually drive in a specially equipped van taking different measurements. Periodic drive testing is typically conducted not only to maintain proper system adjustments, but also, for example, when a new cell or cell site is added, when there is a big change in traffic pattern in the system (e.g., due to a new highway), and/or the addition or relocation of the mobile switching center (MSC) as a few illustrative examples.
All the above mentioned factors and others demand that the system be drive tested since a sub-optimized communication network may have many revenue-impacting effects such as higher drop call rates which result in lower minutes of use (MOU) by system users, poor customer retention rates due to poor system performance and uneven traffic distribution caused by a network that is not optimized.
A typical drive-test will require a few technicians and/or RF engineers to drive around taking plots of RF signal levels, etc. From the result of the drive tests, optimization of the system is performed. Optimization can include adjustment of signal power levels for different cells, tilting of antennas on towers, adding antenna towers to improve coverage in certain heavy usage locations, etc. Drive-testing although beneficial is time consuming and requires a lot of manual work on the part of a group of technicians to perform the test properly.
In accordance with one embodiment of the invention, a communication network 100 such as that shown in
It should be noted that although in the described embodiment a GPS receiver is used to provide geographical location information, any type of geographical positioning technique can be used to provide communication device position/location information. As illustrative examples, other geographical positioning techniques that can be used in the present invention can include Galileo, Time Difference of Arrival (TDOA), WiFi-positioning location methods, Loran-C, triangulation, etc.
Information received at the system controller 112 can be stored in a database 114. The RSSI/GPS information stored in the database 114 can then be analyzed in order to perform network optimization. The analysis of the information can be performed for example using mapping software that generates RF coverage plots, etc.
The system controller 112 or another system component can interrogate the communication devices 108, 110 periodically in order to take multiple measurements at various locations in the network 100. This interrogation can occur either during a long period of time (e.g., over different days) or over a short period of time (e.g., over a few minutes). Although the device collecting the information is referred to as a system controller or controller, it can comprise any system device that can generate a message to one or more of the communication devices 108, 110 requesting the system performance data (e.g., quality of signals transmitted to the communication devices 108, 110, etc.).
Using the RSSI information along with the GPS location information where the RSSI measurement was taken allows the communication network to draw detailed RF plots over most of the network 100. The RF plots will allow for appropriate actions to be taken in order to optimize the communication network. As illustrative examples, these actions can include but are not limited to, increasing/decreasing the RF power levels on one or more cell sites, adjusting antenna angles, adding a new cell site in heavily congested areas, etc. By automatically querying one or more of the communication devices operating within the communication network 100 a lot of useful system information can be gathered in a short period of time.
In order to reduce the effect on the system's performance, the automatic querying of the communication devices 108, 110 can occur during designated periods of time, during certain days/nights, groups of communication devices can be done during certain periods of time, etc. In some networks 100 where thousands of communication devices are operating within the network, a lot of system optimization information can be gathered without having to use manual drive-tests as in the prior art.
Referring now to
Communication device 200 further includes a global positioning system (GPS) receiver 210 which can be located separately from receiver 206 or integrated as part of receiver 206. Receiver 206 further includes a relative signal strength indicator (RSSI) circuit that can measure the signal strength of a received signal at communication 200. The RSSI circuit 212 can take anyone of a number of well known forms, for example hardware, software, firmware or a combination of these. In accordance with one embodiment of the invention, when communication device 200 receives a signal from system controller 112 requesting that a signal quality measurement (e.g., RSSI, etc.) be taken, the controller 208 requests the RSSI information from RSSI circuit 212 as well as the GPS location information from GPS receiver 210. The controller 208 can then cause transmitter 204 to send a message to the system controller 112 which includes the RSSI information and the GPS information were the RSSI measurement was taken. All of the above can be performed automatically without the user of the communication device 200 knowing that the measurement information is being sent to the system controller 112.
Referring now to
In another embodiment, the system can automatically adjust (raise/lower) cell site power levels based on the collected information. An output such as a print out can also be generated which informs service crews/ RF engineering team of the need for example of adjusting the antenna angles on some of the antenna towers. Other embodiments may let the system know that a certain number of users were in a certain geographical area within the communication network 100 during a given period of time. If a predetermined number of users are located in a certain system coverage area as determined by the GPS information, the output information generated may let the system know that another cell site may be needed in the area, or the geographical area covered by certain cell sites may need to be adjusted.
The number of different adjustments or optimization performed based on the collected information can be many. The level of automation of the adjustments will also depend if the adjustments can be done by the system itself without human intervention (e.g., adjust power levels) or may require some type of manual intervention (e.g., technician needed to adjust antenna pattern). The system can also be manually overwritten if required, if for example, there is an immediate need of collecting system information at a certain period of time (e.g., after a new cell site has been added). Other system uses can include, determining if there is any RSSI degradation during certain times of the day, etc. The number of times a particular communication device or devices are queried for RSSI information can be changed depending on the information collection requirements of the communication network administrator.
Although RSSI has been discussed, other received parameters such as bit-error-rate (BER) or other measurements that can be taken by the communication devices 108, 110 can also be collected in addition to or instead of the RSSI information.
While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.