Wi Fi Location Based Services 4.Design Guide Cisco Location Based Services Architecture Design Zone for Mobility Cisco Location Based Services Architecture This chapter describes the Cisco Location Based Services LBS architecture and has the following main sections RF Fingerprinting Location Aware Cisco UWN Architecture Role of the Location Appliance Accuracy and Precision Tracking Clients, Assets and Rogue Devices Cisco Location Control Protocol LOCP RF Fingerprinting Cisco RF Fingerprinting refers to a new and innovative approach that significantly improves the accuracy and precision of traditional signal strength lateration techniques.Vertu, the company that sells 50,000 smartphones, is shutting down its UK manufacturing operations.But everyone saw it coming.F_110526016_d7w5r1cYYXx0iMaXXjNNlJ8yaLJtnp1H.jpg' alt='10000 High Definition Windows Icons Location' title='10000 High Definition Windows Icons Location' />Cisco RF Fingerprinting offers the simplicity of an RSSI based lateration approach with the customized calibration capabilities and indoor performance previously available only in location patterning solutions.RF Fingerprinting significantly enhances RSS lateration by using RF propagation models developed from radio propagation data gathered directly from the target environment or environments very similar to it.RF Fingerprinting offers the ability to calibrate an RF model to a particular environment in a fashion similar to but more expeditious than that described for location patterning.In addition to the use of prepackaged propagation models, RF Fingerprinting offers the ability to develop customized models that are based on on site data collection.This process allows for the overall attenuation characteristics of the actual environment to be taken into consideration during the derivation of both 2.GHz and 5 GHz path loss models.For each calibration grid location, the physical location coordinates of the calibration client provided by the calibration operator are recorded along with the client RSSI from three or more LWAPP enabled access points.The data accumulated during the calibration phase is statistically processed and groomed, then used to build an RF propagation model used to predict tracked device RSSI around each access point, where the path loss exponent, shadow fading standard deviation, and PL1meter values are calculated from the sample calibration data so as to better reflect specific propagation anomalies present in the environment.This process consists of several computational cycles where the previously mentioned parameters are calculated for each band.The minimum mean square error MMSE estimation technique is used to obtain the initial values for the parameters, as shown in Figure 3 1, where the path loss exponent is represented by the slope of the applicable MMSE line of best fit that is, either default or corrected fit.However, note that in the RF Fingerprinting approach, the selection of a location path loss model does not end with MMSE.Rather, MMSE is used only as the starting point for the selection of finalized parameters for each band, with the ultimate goal being the optimization of the final path loss model as it pertains to location accuracy.RF Fingerprinting does not rely on good location performance being a by product of a RF propagation model that simply provides good coverage mapping.Figure 3 1 MMSE Estimation To locate a mobile client during the operational phase of RF Fingerprinting, RSS multi lateration is performed using either a pre packaged RF model or a customized model created during the calibration phase.This process yields the coordinates of the data point with the highest potential of correctly representing the tracked devices current location.Additional information gleaned from statistical analysis of the distribution of calibration data is then used to further improve location accuracy and precision.Cisco RF Fingerprinting offers several key advantages over traditional approaches Uses existing LWAPP enabled Cisco Unified Networking ComponentsUnlike some other solutions, the location aware Cisco UWN with RF Fingerprinting provides a Wi Fi based RTLS alongside of voice and data services using a combined infrastructure.The Cisco Location Appliance supports location and statistics history and serves as a centralized positioning engine for the simultaneous tracking of up to 2.Optional chokepoint triggers can be added to the solution to provide presence and proximity detection if desired, allowing for very granular detection of asset tags, within a range of 2.No proprietary client hardware or software requiredThe location aware Cisco UWN with RF Fingerprinting uses a network side location model.Because of this, Cisco RF Fingerprinting can provide location tracking for a wide variety of industry standard Wi Fi clients and not just those with popular Windows based operating systems without the need to load proprietary client tracking software or location enabled wireless drivers in each client.This includes popular Vo.IP handsets such as the Cisco 7.G, devices for which such proprietary add on location tracking client software is not available.Supports popular Wi Fi active RFID asset tags Because the location aware Cisco UWN implements RF Fingerprinting as a network side model, there is no dependency on proprietary software being resident in RFID asset tags in order to allow for localization.This enables the location aware Cisco UWN to interoperate with active RFID asset tags from popular vendors including Aero. Download Roster Updates Madden 08 Pc Rosters . Scout, Pan. Go Networks, Where.Net, G2 Microsystems and others.Asset tags that support the Cisco Compatible Extensions for Wi Fi Tags specification can take advantage of advanced features introduced with software Release 4.Cisco UWN. Cisco makes this specification available to Cisco Technology Development Partners CTDP and encourages the development of interoperable active RFID tag hardware in compliance with the specification.Better accuracy and precisionCisco RF Fingerprinting yields significantly better performance than solutions employing pure triangulation or RSS lateration techniques.These techniques typically do not account for effects of attenuation in the environment, making them highly susceptible to reductions in performance.The advantages of Cisco RF Fingerprinting technology start where these traditional approaches leave off.Cisco RF Fingerprinting begins with a significantly better understanding of RF propagation as it relates specifically to the environment in question.With the exception of the calibration phase in location patterning, none of the traditional lateration or angulation approaches discussed thus far take environmental considerations directly into account in this manner.RF Fingerprinting then goes a step further, by applying statistical analysis techniques to the set of collected calibration data.This allows the Cisco Location Appliance to further refine predicted location possibilities for mobile clients, culling out illogical or improbable possibilities and refining accuracy.The net result of these efforts is not only better accuracy but significantly improved precision over traditional solutions.Reduced calibration effortThe Cisco RF Fingerprinting technology offers the key advantages of an indoor location patterning solution but with significantly less effort required for system calibration.Although both solutions support on site calibration, the Cisco RF Fingerprinting approach offers less frequent re calibration and can operate with a larger inter access point spacing than location patterning solutions.Cisco RF Fingerprinting can also share RF models among similar types of environments and includes pre packaged calibration models that can facilitate rapid deployment in typical indoor office environments.Location Aware Cisco UWN Architecture The overall architecture of the location aware Cisco Unified Wireless Network is shown in Figure 3 2.Figure 3 2 Location Aware Cisco UWN Architecture Access points forward information to WLAN controllers regarding the detected signal strength of any WLAN clients, asset tags, rogue access points, or rogue clients.In normal operation, access points focus their collection activities for this information on their primary channel of operation, going off channel and scanning the other channels in their regulatory channel set periodically.The collected signal strength information is forwarded to the WLAN controller to which the access point is currently registered, which aggregates the information.How to Become a High Profile Personal Assistant.In The Assistant Economy, Dissent Magazine analyzes the privileged and idiosyncratic career path of personal assistants who serve a single high profile professional, often in a creative field, in a job that often provides no direct promotion opportunities a movie director cant train you to replace them but plenty of indirect ones.A few practical tips To get hired, get aggressive.These idiosyncratic jobs often arent advertised publicly.If you want to assist a famous artist, writer, or director, find any way to interact with them.New Yorker writer Adam Gopnik found his assistant when she approached him after a reading.As White House Deputy Chief of Staff, Karl Rove hired an assistant who had organized a seamless visit for him to the Harvard campus.Unfortunately, this approach gives a hefty advantage to those who attend elite colleges or grow up with family connections.If youre lacking both, youll need to find ways to distinguish yourself, and keep an eye out for any potential employers visiting your area for talks or conferences.Be ready to do anything.Heres an advantage for the less elite applicants Emphasize your willingness to do any task, like running personal errands which youll inevitably be assigned anyway.Assistants get breathtaking access to the inner workings of creative industries, but only because they have to handle all the attendant details.This includes a lot of managing your bosss ego.To move on, get aggressive again.The personal assistant role is an unusually dead end job, since its unusually closed off from the larger workplace, and since the manager is at the top of the field, not one rung up the corporate ladder.Its in an employers best interest to keep the assistant around forever, and some will get very selfish about it.So when its time to leave, you need to do the work of finding your next step.The Assistant Economy Dissent.
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