Patent Application
20140044005
This invention relates to wireless networking and more particularly to conducting wireless site surveys.
Designing wireless networks that provide adequate network quality in an operating environment (e.g., an office building) is a non-trivial task. Environmental factors can affect the propagation of radio frequency (RF) waves. For example, walls, doors, windows, and the like can reflect, refract, and attenuate RF waves in ways that may be difficult to predict.
As a result, the operating environment a wireless network is deployed in is a significant variable to consider when designing the wireless network for that environment. The quality of the wireless network may depend on, for example, the number of wireless access points deployed and their respective installation locations.
Accordingly, network designers may perform a wireless site survey to determine whether the wireless environment provides suitable wireless network access. Wireless site surveys, however, can be sophisticated technical procedures that may require the expertise of a professional network designer. Therefore a need exists for an improved approach to conducting wireless site surveys.
A system for conducting wireless site surveys of a wireless environment is provided. A wireless interface controller controls a wireless interface during a scan of a wireless frequency band. A user interface module receives a set of wireless network design criteria, and a measurement module obtains a set of wireless signal information based on a set of wireless signals received during the scan of the wireless frequency band. An analysis module compares the set of wireless signal information to the set of wireless network design criteria and automatically determines whether the set of wireless network design criteria is, at least in part, satisfied. The user interface module provides an indicator that indicates whether the set of wireless network design criteria is, at least in part, satisfied.
A computer-implemented method of conducting a wireless site survey for a wireless environment is also provided. A set of wireless network design criteria is received. A wireless frequency band is scanned to receive a set of wireless signals. Individual wireless signals in the set of wireless signals are measured to obtain a set of wireless information associated with the set of wireless signals. The set of wireless signal information is compared to the set of wireless network design criteria, and whether the set of wireless network design criteria is, at least in part, satisfied is determined. An indicator is provided that indicates whether the set of wireless network design criteria is, at least in part, satisfied.
A method of conducting a wireless site survey for a wireless environment is further provided. A set of wireless network design criteria is provided to a wireless network design system. The wireless network design system is positioned at a location within the wireless environment. A wireless frequency band is scanned using the wireless network design system, and whether the set of wireless network design criteria is, at least in part, satisfied is determined based on an indicator automatically provided by the wireless network design system. The wireless environment is reconfigured when the indicator provided by the wireless network design system indicates that at least one wireless network design criterion in the set of wireless network design criteria is not satisfied.
The invention may be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
A system and method for conducting wireless site surveys using wireless network design criteria are provided. A user may establish a wireless environment by distributing wireless access devices throughout a site. The user may specify a set of wireless network design criteria that corresponds to a desired quality of wireless service level. The user may then collect and measure wireless signals and compare the wireless signals to the design criteria as part of a wireless site survey. An audio or visual indicator is provided to automatically indicate whether the wireless environment satisfies the wireless network design criteria. If the wireless environment does not satisfy the design criteria, then the user may reconfigure the wireless environment and repeat the live site survey until the wireless design criteria is satisfied. In this way, a network designer may advantageously determine whether a wireless environment provides a desired quality of wireless service level while actively surveying the site. As a result, this improved approach to conducting live site surveys may allow novice users to conduct live site surveys.
Referring to
A wireless access device 112 provides wireless access to a wired network such as, for example, a local area network (LAN) or a wide area network (WAN), e.g., the Internet. Accordingly a wireless access device 112 includes one or more access points 114, i.e., one or more transceivers (e.g., radios). Some wireless access devices 112 may include more than one access point 114 for exchanging wireless signals. A wireless access device 112 that includes multiple access points 114 may be referred to as a wireless array.
Access points 114 in a wireless array 112 may operate in the 2.4 GHz (gigahertz) and 5 GHz frequency bands. Under the IEEE 802.11 standards, these frequency bands are divided into channels with each channel corresponding to a particular frequency. The IEEE 802.11b and 802.11g standards, for example, divide the 2.4 GHz frequency band into fourteen channels, channels 1-14, spaced 5 MHz (megahertz) apart. The IEEE 802.11a standard, as another example, divides the 5 GHz band into twenty-three non-overlapping channels.
The wireless network designer 102 includes modules that facilitate the measurement and analysis of wireless signals in a wireless environment. The wireless network designer 102, in this example, includes: a wireless interface controller 116 that controls (i.e., drives) the wireless interface 110 during a wireless site survey; a use interface module 118 that receives wireless network design criteria 120 from a user 121 via one or more input devices 122 and provides user interfaces at a display device 108; a measurement module 124 that measures wireless signals received at the wireless interface 110 from wireless access devices 112; and an analysis module 126 that determines whether the wireless signals satisfy the wireless network design criteria 120. Input devices 122 may include, for example, a keyboard, a pointing device (e.g., mouse, stylus, touchscreen, touchpad, etc.), and the like. The display device 108 may be, for example, a computer monitor, a computer screen, or other electronic visual displays. The wireless network design system 100, in this example, includes a data store 128 that stores the wireless network design criteria 120 received from the user 121. The wireless network designer 102 may also include a channel filter 130 that instructs the wireless interface 110 to selectively monitor wireless channels during a wireless site survey as discussed in further detail below.
Wireless network design criteria 120 may include, for example: a minimum number of wireless access devices 112 observed (i.e., detected) in the wireless environment; a minimum number of wireless access points 114 observed in the wireless environment; and the quality of wireless signals observed in the wireless environment. The quality of wireless signals may be assessed based on the strength of received wireless signals and the signal-to-noise ratio (SNR) observed in the wireless environment.
The strength of received signals, i.e., received signal strength, may be quantified as a dBm value: the power ratio in decibels (dB) of the measured power in Watts (W) of a wireless signal referenced to one milliwatt (mW). A suitable signal strength for wireless signals broadcast in a wireless environment may be between, for example, around −100 dBm to around −20 dBm.
To measure and analyze the wireless environment, the wireless network design system 100 may perform a series of measurement cycles to observe the wireless signals the wireless access devices 112 broadcast throughout the wireless environment. During a measurement cycle, the wireless network designer 102 may instruct the wireless interface 110 to tune to a particular wireless channel. Once tuned to a wireless channel, the wireless network designer 102 monitors (i.e., listens) for wireless signals broadcast on that channel, extracts data from wireless signals received at the wireless interface 110 from the wireless access devices 112, and compares the extracted data to the wireless network design criteria 120. After completing a measurement cycle, the wireless network designer 102 instructs the wireless interface 110 to tune to a new channel and repeats the monitoring, measurement, and comparison procedures. Based on the results of the measurement cycles, the wireless network designer 102 determines whether the wireless environment satisfies the wireless network design criteria 120. As discussed further below, the wireless network design system 100 provides visual or audible indicators that indicate whether the set of wireless design criteria 120 is or is not satisfied.
The wireless interface controller 116, in this example, controls the wireless interface 110 during a wireless site survey. The wireless interface controller 116 issues commands to the wireless interface 110 that instruct the wireless interface to tune to a particular wireless channel and monitor that wireless channel in order to collect wireless signals broadcast on that channel. As an example, the wireless interface controller 116 may instruct the wireless interface 110 to scan the 2.4 GHz and 5 GHz frequency bands during a wireless site survey. During the scan, the wireless interface 110 iteratively tunes to the channels of frequency bands, e.g., channels 1, 6, 11, etc. in the 2.4 GHz frequency band under the IEEE 802.11b/g standard and channels 36, 40, 44, etc. in the 5 GHz frequency band under the IEEE 802.11a standard.
While the wireless interface 110 is tuned to a channel, the wireless interface may actively monitor the channel by broadcasting probe requests. If an access point 114 is tuned to the same channel, the access point may transmit a response to the wireless interface. The wireless network design system 100 may then associate with the access point 114, exchange a series of wireless signals, and measure the wireless signals to determine whether the wireless network design criteria 120 is satisfied as discussed further below. Additionally or alternatively, the wireless network design system 100 may measure the wireless signals received as responses to the probe requests to determine whether the wireless design criteria 120 is satisfied. The wireless interface 110 may also passively monitor the channel by listening for beacons broadcast by one or more access points 114 tuned to the same channel. An access point 114 may broadcast beacons at a periodic interval, e.g., every one-hundred milliseconds (ms), to announce its presence in the wireless environment. Beacons broadcast by an access point 114 may include identifying information such as, for example, the SSID for the access point (service set identifier). The wireless network design system 100 may measure the wireless signals received as beacons broadcast by the access points 114 to determine whether the wireless network design criteria 120 is satisfied. Additionally or alternatively, the wireless network design system 100 may use the information in the probe requests to associate with the access points 114 and initiate an exchange of wireless signals to determine whether the design criteria 120 is satisfied as mentioned above.
The wireless network design system 100 may be configured to monitor each available channel in the wireless frequency bands. To improve performance, however, the wireless network designer 102 may include a channel filter 130 to selectively monitor the channels of the frequency bands. The channel filter 130 may be, for example, a driver that instructs the wireless interface controller 116 to monitor a set of specified channels. A user 121 may provide the wireless network design system 100 with user input corresponding to a set of channels to monitor during the wireless site survey. Accordingly, the channel filter 130 may instruct the wireless interface controller 116 to skip over or ignore unselected channels during the scan of the wireless environment. The user 121 may also selectively configure the channel filter 130 such that the wireless interface 110 monitors channels in an active mode or a passive mode. The selection of an active mode or passive mode may also be received at the wireless network design system 100 as user input. In addition, a user 121 may specify a desired scan interval, i.e., the amount of time the wireless interface 110 monitors a channel before tuning to the next channel. The wireless network design system 100 may similarly receive the scan interval from the user 121 as user input.
Having received wireless signals at the wireless interface 110, the measurement module 124 processes the received wireless signals to extract data from the wireless signals and determine the quality of the wireless signals. The data the measurement module 124 extracts from the wireless signals may be related to the access points 114 that broadcast the wireless signals. Data extracted from the wireless signals may include, for example: the base physical address of the wireless access device 112 and the respective physical addresses of the access points 114, e.g., the BSSID (basic service set identifier); the respective SSIDs of the access points; information indicating whether the channel is bonded; and the like. Channel bonding refers to the technique of broadcasting wireless signals on two separate non-overlapping channels to increase throughput. The measurement module 124 may determine whether the channel is bonded by identifying the primary channel in the received packet and by examining the packet flag of the received packet. The measurement module 124 may also determine the signal strength of the wireless signals by converting the power of the wireless signal to a dBm value as discussed above.
The measurement module 124, in this example, may also determine the signal-to-noise ratio observed in the wireless environment based on the wireless signals received at the wireless interface 110. The measurement module 124 may quantify the SNR as an integer value. The measurement module 124, in this example, may determine the SNR by dividing the average power of the received wireless signals by the noise floor of the average power of noise observed in the wireless environment. Signal-to-noise ratio may be defined as the power ratio between a signal (i.e., meaningful information) and background noise (i.e., unwanted signals) where P is the average power. Accordingly, the SNR may be obtained using the following equation:
where Psignal is the average power of the received wireless signals and Pnoise is the average power of noise observed in the wireless environment.
Having measured the received wireless signals, the analysis module 126 compares the measurement information to the wireless network design criteria 120. For example and as discussed further below, the analysis module 120 may: compare signal strength of the received wireless signals to the signal strength criterion; compare the observed signal-to-noise ratio to the SNR criterion; compare the number of observed wireless access devices 112 to the specified minimum number of wireless access devices; and compare the number of observed access points 114 to the specified minimum number of access points. The analysis module 126 may initiate visual or audible feedback that indicates whether the set of wireless network design criteria 120 is satisfied. For example, the analysis module 126 may instruct the user interface module 118 to adjust the user interface displayed at the display device 108 to visually indicate whether the set of design criteria 120 is satisfied. Additionally or alternatively, the analysis module 126 may instruct the audio output device 106 to playback a tone, audio file, or the like, when the set of wireless network design criteria 120 is satisfied.
The analysis module 126 may determine whether the overall set of wireless network design criteria 120 is satisfied globally. If each individual wireless network design criterion in the set of wireless network design criteria 120 is satisfied, then the analysis module 126 may determine that the set of wireless network design criteria is satisfied globally. For example, if the analysis module 126 determines that the wireless environment includes at least the minimum number of wireless access devices 112 or access points 144, that the strength of received wireless signals are at least equal to the minimum signal strength value, and that the observed SNR in the wireless environment does not equal or exceed, i.e., is below, the maximum SNR value, then the analysis module may determine the set of wireless network design criteria 120 is satisfied globally. If the analysis module 126 determines that at least one individual wireless network design criterion is not satisfied, then the analysis module may determine that the set of wireless network design criteria 120 is not satisfied.
The analysis module 126 may also determine whether a wireless network design criterion is satisfied on an individual basis. For example, the analysis module 126 may determine whether wireless signals broadcast on each channel observed in the wireless environment (e.g., channels 1, 6, 9, and 13) satisfy the wireless signal strength criterion. If wireless signals broadcast on each of the observed channels satisfy the wireless signal strength criterion, then the analysis module 126 may determine that the wireless signal strength criterion for the set of wireless network design criteria 120 is satisfied. If some of the wireless signals broadcast on one of the observed channels (e.g., channel 6) do not satisfy the wireless signal strength criterion, however, then the analysis module 126 may determine that the wireless signal strength criterion for the set of wireless network design criteria 120 is not satisfied. In turn the analysis module 126 may determine that the set of wireless network design criteria 120 is not satisfied globally.
The analysis module 126 may determine that an individual wireless network design criterion is (or is not) satisfied based on whether a predetermined amount of received wireless signals satisfy the criterion. The amount of wireless signals that must satisfy the criterion may be a default or user configurable setting. For example, the predetermined amount of wireless signals that must satisfy the wireless network design criterion may be specified as 75%. Accordingly, if 25% or more of received wireless signals do not satisfy the wireless signal strength criterion, then the analysis module 126 may determine that the wireless signal strength criterion is not satisfied, either globally or for a particular channel as discussed above. Likewise if 75% of received wireless signals do satisfy the wireless signal strength criterion, then the analysis module 126 may determine that the wireless signal strength criterion is satisfied. A user may specify alternative percentages to suit the needs of a particular wireless environment. It will be understood that additional or alternative approaches to determining whether the set of wireless network design criteria 120 is satisfied may be selectively employed according to the wireless access needs of the wireless environment under survey.
The user interface module 118 provides one or more user interfaces that receive the set of wireless network design criteria 120 from the user 121s and that provide one or more visual indicators to indicate whether the wireless network design criteria is satisfied. Referring to
As seen in the example user interface 200 shown in
A user 121 may also specify that the wireless network design system 100 should observe a minimum number of wireless access devices 112 (“mode 2”) or a minimum number of access points 114 (“mode 3”) in order for the wireless network design criteria 120 to be satisfied. The minimum number of wireless access 112 devices refers to the total number of distinct wireless access devices observed in the wireless environment, e.g., the total number of wireless arrays. The minimum number of total access points 114 refers to the total number of distinct access points observed in the environment even if, for example, the distinct access points are included in the same wireless array 112. Accordingly, four distinct wireless arrays 112 each having four access points 114 results in a wireless environment that includes sixteen distinct access points. The user interface 200 may include drop-down lists 210 to specify the minimum number of total wireless access devices 112 or access points 114 as shown by way of example in
The measurement module 124 may determine the total number of distinct access points 114 based on the respective physical addresses of the access points, e.g., the BSSIDs of the access points. Each access point 114 may be respectively associated with a unique physical address, e.g., 00:0f:7d:01:db:c4. The measurement module 124 may thus extract the BSSID from received wireless signals and count the total number of unique physical addresses observed in order to determine the total number of distinct access points 114 observed in the wireless environment. The measurement module 124 may determine the total number of distinct wireless access devices 112 in the wireless environment in a similar fashion if the wireless access device includes a single access point 114. Where the wireless access devices 112 are wireless arrays having multiple access points 114, the measurement module 124 may determine the total number of distinct wireless arrays based on the base physical address (e.g., base MAC address) of the wireless access device. Access points 114 in wireless arrays 112 may respectively correspond to physical addresses that increment from the base physical address. Accordingly, the measurement module 124 may determine the total number of wireless access devices 112 by counting the number of unique base physical addresses observed during the scan of the wireless frequency band. Wireless signals (e.g., wireless beacons) may include additional information extracted by the wireless network designer 102, which indicates, e.g., the model number of a wireless access device 112, the number of access points 114 in a wireless array, etc.
Also seen in
As discussed above, the wireless network designer 102 may include a channel filter 130 for selectively monitoring channels during a wireless site survey. Referring to
The user 121 may also specify whether the wireless network interface 110 should monitor the channels in an active or passive mode. The user interface 220, in this example, includes a pair of radio buttons 232 for respectively selecting the active mode or passive mode. Additionally, a user 121 may specify the scan interval as mentioned above. The user interface 220, in this example, may include a textbox 234 for specifying the scan interval, e.g., 0.5 seconds (s).
Once the scan of the wireless frequency bands is complete, the user interface module 118 may construct a user interface that includes the results of the scan as well as indicators that indicate whether the set of wireless network design criteria 120 is satisfied. The user interface module 118 may present the user interface at the display device 108 to provide the results of the wireless site survey. Referring to
The user interface 250 displaying the results of the wireless site survey, in this example, displays respective result tables 252 and 254 for the 2.4 GHz and 5 GHz frequency bands. The result tables 252 and 254 may include a line item 256 for each of the wireless channels observed during the scan of the frequency bands as shown by way of example in
The user interface module 118 may also include in the user interface 250 visual indicators 260 and 262 that indicate whether the wireless signals broadcast on an observed channel satisfy the specified network design criteria 120, e.g., the signal strength criterion. For example, the user interface module 250 may selectively adjust the background color 260 of a channel line item 256 based on whether wireless signals broadcast on that channel satisfy the wireless network design criteria 120. The line items 256a-b, 256-h, and 256j shown by way of example in
In
The user interface 250 displaying the results of the wireless site survey may also include a pass/fail display element 262, e.g., a global compliance indicator, that visually indicates whether the overall set of wireless network design criteria 120 is satisfied, e.g., the signal strength of observed wireless signals, the minimum number of wireless access devices 112 or access points 114, and the signal-to-noise ratio. If the analysis module 126 determines that these wireless network design criterions are cumulatively satisfied, the global compliance indicator 262 may indicate that the set of wireless network design criteria 120 is satisfied. The user interface module 118 may indicate compliance or noncompliance with the overall set of design criteria 120 based on a selective coloring (e.g., white/gray, green/red, etc.) of the global compliance indicator 262. Because some of the observed wireless signals shown by way of example in
The wireless network design system 100 may additionally indicate satisfaction of or compliance with the wireless network design criteria 120 using an audible indicator. If the analysis module 126 determines that the set of design criteria 120 is satisfied, the analysis module may instruct the audio output device 106 to initiate playback of a tone, audio file, or other audible indicator as mentioned above. The user interface 250 displaying the results of the wireless site survey may also include an input element 264, e.g., a checkbox, to toggle the use of an audible indicator to indicate satisfaction of the wireless network design criteria 120.
Referring now to
In response to the determination that the wireless environment does not satisfy the wireless network design criteria 120 at some locations 304b, the user may reconfigure the wireless environment. Reconfiguring the wireless environment may include, for example: adjusting the number of wireless access devices 112 or access points 114 deployed in the wireless environment; adjusting the location of the wireless access devices within the wireless environment; adjusting the orientation of wireless access devices where, e.g., the wireless access devices include directional antennas; selecting a different type of wireless access device, e.g., a wireless array having eight access points instead of four access points; redistributing channel assignments among wireless access devices or among access points in a wireless array; adjusting the transmitting power of a transceiver; and the like. It will be understood that the configuration of the wireless environment will depend on the particular site the wireless environment is deployed in as well as the particular requirements for wireless service within the site. The wireless network design system 100 provided advantageously helps to determine when those requirements are satisfied.
Referring back to the example site 300 under survey in
The user may repeat the wireless site surveys at the measurement locations 304b that previously did not receive adequate wireless access. Having added another wireless access device 112b and relocated the wireless access devices 112 at the site 300 as shown in
Referring now to
The user may then provide a wireless network design system 100 with a set of wireless network design criteria 120 (step 406). The wireless network design criteria 120 may correspond to a desired quality of wireless service observed at the site under survey. The wireless network design criteria 120 may include, for example, a desired signal strength threshold or range, a desired number of observed wireless access devices 112 or access points 114, and a signal-to-noise ratio as discussed above. The user may also select, using the wireless network design system 100, a set of channels to monitor during the wireless site survey (step 408). For example, if the user configures the wireless access devices 112 to broadcast on certain channels, the user may select only those channels to monitor during the wireless site survey.
The user may then select a measurement location at the site under survey at which to monitor wireless signals broadcast by the wireless access devices 112 (step 410). The user may position the wireless network design system 100 at the selected location (step 412) and initiate a scan of the wireless frequency bands (step 414) to measure wireless signals received at the selected location. As discussed above, the wireless interface controller 110 of the wireless network designer 102 scans the channels of the wireless frequency bands during the wireless site survey. If the user has not selected a particular channel (step 416), the channel filter 130 instructs the wireless interface controller 116 to skip to the next channel in the frequency band (step 418). If the user has selected a channel for monitoring (step 416), then the wireless interface controller 116 instructs the wireless interface 110 to tune to the frequency for the selected channel (step 420). The wireless network designer 102 then monitors the channel for wireless signals broadcast by the wireless access devices 112 on that channel and received at the wireless interface 110 (step 422). If wireless signals are received on the channel (step 424), then the measurement module 124 may extract wireless signal data from the wireless signals and measure the wireless signals as discussed above (step 426). The analysis module 126 may then compare the extracted wireless signal data and measurements to the wireless network design criteria 120 (step 428) to determine whether the wireless network design criteria 120 is satisfied as also discussed above. If there are additional channels in the frequency bands to monitor (step 430), the wireless interface 110 may go to the next channel (step 418) and repeat steps 416-428 to measure any wireless signals received at the next channel.
If there are no additional channels to monitor (step 430), then the wireless networking design system 100 may indicate whether the set of wireless network design criteria 120 is satisfied. The wireless network design system 100 may indicate whether the set of design criteria 120 is satisfied (step 432) using visual indicators presented on a user interface that is displayed on a display device 108 or audible indicators output from an audio output device 106 as discussed above.
If the wireless network design system 100 indicates that the set of wireless network design criteria is not satisfied at the selected location (step 434), the user may reconfigure the wireless environment (step 436) and repeat steps 414-434 to conduct a wireless site survey in the reconfigured wireless environment. If the wireless network design system 100 indicates that the set of wireless network design criteria is satisfied at the selected location (step 434), the user may decide to perform additional measurements (step 438) at another location of the site. Accordingly, the user may select a new measurement location at the site (step 440), position the wireless network design system 100 at the newly selected location (step 412), and repeat steps 414-438 to perform a wireless site survey at the newly selected location. If the user has conducted a wireless site scan at all desired locations, the user may conclude the wireless site survey (step 442).
It will be understood that the example steps shown in the flowchart 400 of
It will also be understood and appreciated that one or more of the processes, sub-processes, and process steps described in connection with
The executable instructions may be implemented as a computer program product having instructions stored therein which, when executed by a processing module of an electronic system (e.g., a wireless network design system in
It will also be understood that the term “in signal communication” as used in this document means that two or more systems, devices, components, modules, or sub-modules are capable of communicating with each other via signals that travel over some type of signal path. The signals may be communication, power, data, or energy signals, which may communicate information, power, or energy from a first system, device, component, module, or sub-module to a second system, device, component, module, or sub-module along a signal path between the first and second system, device, component, module, or sub-module. The signal paths may include physical, electrical, magnetic, electromagnetic, electrochemical, optical, wired, or wireless connections. The signal paths may also include additional systems, devices, components, modules, or sub-modules between the first and second system, device, component, module, or sub-module.
The foregoing description of implementations has been presented for purposes of illustration and description. It is not exhaustive and does not limit the claimed inventions to the precise form disclosed. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention.
