November 13, 2015 at 07:05High precision Wi-Fi positioning
One of the most popular categories of mobile applications today is that it provides services with location of the device. Many people use positioning systems on their navigation devices, smartphones and tablets. The weakness of these solutions is that the use of the Global Positioning System (GPS) is not available indoors due to the strong signal cancellation by the walls and floors of buildings. This opens up a niche for reliable indoor positioning solutions.
Today, there are a number of approaches and technologies for solving this problem. Cisco has been working on positioning using Wi-Fi technology for several years, given the prevalence of networks (in almost every room) and devices (in almost every person).
The first development began in 2007 when Cognio was acquired, whose spectral analysis engine was integrated into Cisco Aironet Wi-Fi access points. The ability to analyze broadcasts for interference and determine their impact on Wi-Fi network performance has opened up new possibilities for ensuring the reliability and performance of wireless networks. New tasks also appeared - to understand where the sources of interference are, because finding them is not always easy, especially if the interference is intentionally created by attackers.
Since then, the algorithm and portfolio of solutions have improved many times and now, in 2015, Cisco offers the latest positioning solution with high accuracy, which allows you to determine the Wi-Fi coordinate of the device with an accuracy of 1m. In the coming days, Cisco will open this solution to order in Russia.
Positioning in wireless networks can be implemented in several ways:
1. The pattern recognition method.
This method assumes that at each point the device sees a unique radio picture. The device scans the radio environment - access points and the level of their signals, checks the received radio signal scheme with a list of templates and finds the coordinate of the device. To configure the entire network, it is necessary to carry out a lengthy process of scanning the air of the entire room, in practice several times, as well as conduct regular data calibration, in reality, changes are constantly taking place in the rooms.
The method has the advantage of low equipment costs, but the cost of ownership of such a solution will be high, and the positioning accuracy low.
2. By the access point to which the client is attached.
This method has the advantage of simplicity, but suffers exactly. Indeed, the range of a wireless network can be quite large, the diameter of the spot of illumination can be 50m or more. T.O. this method is better than nothing, but it is unlikely to allow us to collect analytics that are valuable to our customers.
The method allows you to determine the presence of the client rather than position it.
3. Triangulation.
This method has been used by Cisco for several years now and consists in determining the signal strength from the client at 3-4 Wi-Fi access points and position the device in the zone of intersection of the possible location of the client relative to each point. This method is quite informative. With the correct weighting of access points, it allows you to determine the client’s coordinate with an accuracy of 5-7m with a high probability. A good scenario is access points around the perimeter of the room and in the center so that each point in space is “heard” by 3 to 4 Wi-Fi access points. Obstacles in the way of the radio signal will interfere with the accuracy of determining the coordinate. Static obstacles need to be modeled, and moving ones will inevitably have a negative impact on accuracy.
To increase the accuracy of positioning in a Wi-Fi network, access points must be set more often, because signal fading and distance from the access point are exponentially dependent. Near the access point, when moving away from it, the signal level decreases significantly, in the distance - when moving away, the signal level decreases by one unit of distance and it becomes more difficult to calculate the coordinate.
In addition to access points and a wireless network controller, a Wi-Fi network with positioning capabilities receives another element that will calculate coordinates and accumulate data for analytics - the Mobility Services Engine (MSE). Today, the MSE capacity allows you to accumulate data from 100,000 client devices over 2-8 years (depending on the amount of data generated, this usually corresponds to the frequency of movement of devices, and the type of MSE). However, in view of the emerging challenges associated with positioning in Wi-Fi networks, MSE in future versions will acquire a distributed architecture that allows you to collect data from a million devices. In this case, the collected information can be fed to an external analytical engine by API in almost real time.
The implementation of positioning on a Wi-Fi network leads to additional costs for the deployment of infrastructure, while low network operating costs.
4. Angulation or positioning with the definition of the angle of the incoming signal.
The method is a revolutionary development of Cisco, allowing to achieve meter accuracy of positioning a Wi-Fi client. An external accurate positioning module, connected to a Cisco Aironet modular access point, with a special antenna, allows you to additionally determine the angle at which the signal came and narrow down the segment where the Wi-Fi client can be found to the beam. Applying the method of triangulation to such information from 3-4 access points, we obtain a coordinate that with high probability gives accuracy up to 1 m.
Physically, the device is a Cisco Aironet 3600 or 3700 access point with the included accurate positioning module and a special antenna. An antenna is an array of 32 antennas, each of which receives a signal differently than the neighboring one. The algorithm allows you to calculate the angle at which the signal came from the collected data.
The use of beacons using Bluetooth Low Energy (BLE), energy-efficient devices capable of periodically giving signals like a fire detector, is becoming popular. The beacons are able to determine the proximity of devices with BLE enabled and inform the mobile application server that uses this information as the device’s coordinate.
Beacons are attractive because of their low price, however, the cost of operating such a solution will be substantial, as it is necessary to track the actual location and battery power of the beacons, and to do this by means of the physical presence of a specialist at the facilities.
However, when integrating the two approaches, an interesting solution may arise. The Wi-Fi infrastructure provides general positioning, and the coordinates of a particular object, for which it is fundamentally important, is located within 1 m from the device or in 3 m - of the museum exhibit, ticket office, entrance - using a radio beacon. The integration of Wi-Fi and BLE networks at the same time allows to reduce the cost of operating a hybrid network. On the interface to MSE, today you can track the actual location of the beacons relative to the planned one, “alien” beacons, and the accurate positioning module has a built-in beacon in which the battery will not end.
In terms of developing a precise positioning solution, Cisco also monitors battery power and uses integrated information from Wi-Fi networks and BLE devices for positioning and analytics.
Cisco has received a number of awards for its innovative precision positioning module - Best of INTEROP 2015 in Las Vegas (April 2015), Tokyo (June 2015) and Wireless Broadband Alliance in the Best WiFi Service Solution for Consumers or Enterprises nomination in San Jose (October 2015) ) The advantages of the method are high positioning accuracy, low operating costs, integration with BLE.
Positioning a device on a Wi-Fi network can be used for a number of applications:
A) detecting assets labeled with Wi-Fi
B) connecting to a Wi-Fi network based on the location of the client C)
navigating the premises
D) sending highly effective offers based on the location of the client
E) collection of customer behavior analytics.
For applications B) -D) in addition to positioning accuracy, the frequency with which this coordinate is determined is important.
While the client device is not connected to the Wi-Fi network, the coordinate can be determined by the probe requests, which the device periodically sends. The device is not connected to the Wi-Fi network, but we already get information about its movement. Samples are sent by Broadcast, i.e. on all frequency channels - all access points can hear them and triangulation by samples works great.
A small problem is that samples are sent by the device every 15-30-60 seconds, depending on the algorithm specified by the device manufacturer. In addition, mobile device manufacturers are striving to reduce the number of samples sent, as this increases the energy efficiency of the device. By collecting data in this way, we know that the client was at point A and after, for example, 30 seconds at point B, but we don’t have information about what he was doing between A and B. customers such periods of time are also too big.
To increase the frequency of determining coordinates, Cisco developers implemented a method for positioning the device according to data traffic, which allowed increasing the frequency of data collection up to 10 times per minute - FastLocate.
FastLocate can be implemented on a separate module for Cisco Aironet 3600 and 3700 Series Modular Access Points. The WSM module will scan the air and collect information to calculate device coordinates approximately every 8 seconds.
The second FastLocate use case is suitable for any Cisco Aironet access points and does not require an additional module. The access point exits the customer service mode for a short period of time and switches to the ether scanning mode (Enhanced Local Mode - ELM). In ELM, a point, as in the previous case, collects information for calculating the coordinates of devices and switches back to customer service mode. This method has a price in the form of a decrease in Wi-Fi network performance by about 15%, because access points cannot serve clients 100% of the time.
The client device must be connected to a Wi-Fi network, i.e. in the interests of the owner of the premises, he begins to offer Wi-Fi connection to customers, motivating customers with the information content of the application and special offers.
If, as a result, a large proportion of customers connect, the site owner will be able to extract a lot of information for themselves from such analytics:
Today, more than 2000 organizations around the world use solutions with positioning in Cisco Wi-Fi networks and achieve a new level of customer satisfaction, increase the efficiency of their business and marketing programs.
Additional Resources
Cisco Corporate Blog for High-Precision Positioning Solution Cisco Corporate Blog for High-Precision Positioning
Solution
Cisco CMX 10.0 Feature overview and demo video
Cisco Official High-Precision Positioning
Solution Web Page Description of High-Precision Positioning Solution
An article on how to use positioning capabilities in Wi- Fi
Today, there are a number of approaches and technologies for solving this problem. Cisco has been working on positioning using Wi-Fi technology for several years, given the prevalence of networks (in almost every room) and devices (in almost every person).
The first development began in 2007 when Cognio was acquired, whose spectral analysis engine was integrated into Cisco Aironet Wi-Fi access points. The ability to analyze broadcasts for interference and determine their impact on Wi-Fi network performance has opened up new possibilities for ensuring the reliability and performance of wireless networks. New tasks also appeared - to understand where the sources of interference are, because finding them is not always easy, especially if the interference is intentionally created by attackers.
Since then, the algorithm and portfolio of solutions have improved many times and now, in 2015, Cisco offers the latest positioning solution with high accuracy, which allows you to determine the Wi-Fi coordinate of the device with an accuracy of 1m. In the coming days, Cisco will open this solution to order in Russia.
Positioning methods
Positioning in wireless networks can be implemented in several ways:
1. The pattern recognition method.
This method assumes that at each point the device sees a unique radio picture. The device scans the radio environment - access points and the level of their signals, checks the received radio signal scheme with a list of templates and finds the coordinate of the device. To configure the entire network, it is necessary to carry out a lengthy process of scanning the air of the entire room, in practice several times, as well as conduct regular data calibration, in reality, changes are constantly taking place in the rooms.
The method has the advantage of low equipment costs, but the cost of ownership of such a solution will be high, and the positioning accuracy low.
2. By the access point to which the client is attached.
This method has the advantage of simplicity, but suffers exactly. Indeed, the range of a wireless network can be quite large, the diameter of the spot of illumination can be 50m or more. T.O. this method is better than nothing, but it is unlikely to allow us to collect analytics that are valuable to our customers.
The method allows you to determine the presence of the client rather than position it.
3. Triangulation.
This method has been used by Cisco for several years now and consists in determining the signal strength from the client at 3-4 Wi-Fi access points and position the device in the zone of intersection of the possible location of the client relative to each point. This method is quite informative. With the correct weighting of access points, it allows you to determine the client’s coordinate with an accuracy of 5-7m with a high probability. A good scenario is access points around the perimeter of the room and in the center so that each point in space is “heard” by 3 to 4 Wi-Fi access points. Obstacles in the way of the radio signal will interfere with the accuracy of determining the coordinate. Static obstacles need to be modeled, and moving ones will inevitably have a negative impact on accuracy.
To increase the accuracy of positioning in a Wi-Fi network, access points must be set more often, because signal fading and distance from the access point are exponentially dependent. Near the access point, when moving away from it, the signal level decreases significantly, in the distance - when moving away, the signal level decreases by one unit of distance and it becomes more difficult to calculate the coordinate.
In addition to access points and a wireless network controller, a Wi-Fi network with positioning capabilities receives another element that will calculate coordinates and accumulate data for analytics - the Mobility Services Engine (MSE). Today, the MSE capacity allows you to accumulate data from 100,000 client devices over 2-8 years (depending on the amount of data generated, this usually corresponds to the frequency of movement of devices, and the type of MSE). However, in view of the emerging challenges associated with positioning in Wi-Fi networks, MSE in future versions will acquire a distributed architecture that allows you to collect data from a million devices. In this case, the collected information can be fed to an external analytical engine by API in almost real time.
The implementation of positioning on a Wi-Fi network leads to additional costs for the deployment of infrastructure, while low network operating costs.
4. Angulation or positioning with the definition of the angle of the incoming signal.
The method is a revolutionary development of Cisco, allowing to achieve meter accuracy of positioning a Wi-Fi client. An external accurate positioning module, connected to a Cisco Aironet modular access point, with a special antenna, allows you to additionally determine the angle at which the signal came and narrow down the segment where the Wi-Fi client can be found to the beam. Applying the method of triangulation to such information from 3-4 access points, we obtain a coordinate that with high probability gives accuracy up to 1 m.
Physically, the device is a Cisco Aironet 3600 or 3700 access point with the included accurate positioning module and a special antenna. An antenna is an array of 32 antennas, each of which receives a signal differently than the neighboring one. The algorithm allows you to calculate the angle at which the signal came from the collected data.
The use of beacons using Bluetooth Low Energy (BLE), energy-efficient devices capable of periodically giving signals like a fire detector, is becoming popular. The beacons are able to determine the proximity of devices with BLE enabled and inform the mobile application server that uses this information as the device’s coordinate.
Beacons are attractive because of their low price, however, the cost of operating such a solution will be substantial, as it is necessary to track the actual location and battery power of the beacons, and to do this by means of the physical presence of a specialist at the facilities.
However, when integrating the two approaches, an interesting solution may arise. The Wi-Fi infrastructure provides general positioning, and the coordinates of a particular object, for which it is fundamentally important, is located within 1 m from the device or in 3 m - of the museum exhibit, ticket office, entrance - using a radio beacon. The integration of Wi-Fi and BLE networks at the same time allows to reduce the cost of operating a hybrid network. On the interface to MSE, today you can track the actual location of the beacons relative to the planned one, “alien” beacons, and the accurate positioning module has a built-in beacon in which the battery will not end.
In terms of developing a precise positioning solution, Cisco also monitors battery power and uses integrated information from Wi-Fi networks and BLE devices for positioning and analytics. Cisco has received a number of awards for its innovative precision positioning module - Best of INTEROP 2015 in Las Vegas (April 2015), Tokyo (June 2015) and Wireless Broadband Alliance in the Best WiFi Service Solution for Consumers or Enterprises nomination in San Jose (October 2015) ) The advantages of the method are high positioning accuracy, low operating costs, integration with BLE.
Coordinate Update Frequency
Positioning a device on a Wi-Fi network can be used for a number of applications:
A) detecting assets labeled with Wi-Fi
B) connecting to a Wi-Fi network based on the location of the client C)
navigating the premises
D) sending highly effective offers based on the location of the client
E) collection of customer behavior analytics.
For applications B) -D) in addition to positioning accuracy, the frequency with which this coordinate is determined is important.
While the client device is not connected to the Wi-Fi network, the coordinate can be determined by the probe requests, which the device periodically sends. The device is not connected to the Wi-Fi network, but we already get information about its movement. Samples are sent by Broadcast, i.e. on all frequency channels - all access points can hear them and triangulation by samples works great.
A small problem is that samples are sent by the device every 15-30-60 seconds, depending on the algorithm specified by the device manufacturer. In addition, mobile device manufacturers are striving to reduce the number of samples sent, as this increases the energy efficiency of the device. By collecting data in this way, we know that the client was at point A and after, for example, 30 seconds at point B, but we don’t have information about what he was doing between A and B. customers such periods of time are also too big.
To increase the frequency of determining coordinates, Cisco developers implemented a method for positioning the device according to data traffic, which allowed increasing the frequency of data collection up to 10 times per minute - FastLocate.
FastLocate can be implemented on a separate module for Cisco Aironet 3600 and 3700 Series Modular Access Points. The WSM module will scan the air and collect information to calculate device coordinates approximately every 8 seconds.
The second FastLocate use case is suitable for any Cisco Aironet access points and does not require an additional module. The access point exits the customer service mode for a short period of time and switches to the ether scanning mode (Enhanced Local Mode - ELM). In ELM, a point, as in the previous case, collects information for calculating the coordinates of devices and switches back to customer service mode. This method has a price in the form of a decrease in Wi-Fi network performance by about 15%, because access points cannot serve clients 100% of the time.
The client device must be connected to a Wi-Fi network, i.e. in the interests of the owner of the premises, he begins to offer Wi-Fi connection to customers, motivating customers with the information content of the application and special offers.
If, as a result, a large proportion of customers connect, the site owner will be able to extract a lot of information for themselves from such analytics:
Today, more than 2000 organizations around the world use solutions with positioning in Cisco Wi-Fi networks and achieve a new level of customer satisfaction, increase the efficiency of their business and marketing programs.
Additional Resources
Cisco Corporate Blog for High-Precision Positioning Solution Cisco Corporate Blog for High-Precision Positioning
Solution
Cisco CMX 10.0 Feature overview and demo video
Cisco Official High-Precision Positioning
Solution Web Page Description of High-Precision Positioning Solution
An article on how to use positioning capabilities in Wi- Fi
Only registered users can participate in the survey. Please come in.
Why am I interested in positioning in Wi-Fi networks?
- 34% Search for relocatable equipment 33
- 41.2% Customer Behavior / Moving Analytics 40
- 21.6% Delivery of special offers using customer location 21
- 24.7% Search for Wi-Fi Interference Sources 24
- 41.2% Improving customer comfort with an application that takes into account the coordinate of the device 40
- 17.5% Not Interesting 17