Embodiments of the present invention are directed generally toward wireless computer networks, and more specifically to determination and implementation of optimal settings for such networks.
Computers have become commonplace tools in modern society, and many businesses and residences now have one or more computing devices. In a small business, for example, some employees may each use a desktop computer or laptop computer. Some employees may even use more portable computers such as personal digital assistants or “smart” wireless telephones. Similarly, with a family sharing a residence, each family member may have his or her personal computer, or the family members may share one or more computers. Further, both small businesses and personal residences may include various computing appliances that incorporate or otherwise interact with computers. For example, a home residence may include a refrigerator, a “Voice over Internet Protocol” telephone, a digital music server, a digital camera, or an environmental control system that includes or interacts with a computer.
In order to optimize the use and flexibility of these computing devices, a business or family may link them together to form a small private network. Typically, each of the computing devices is connected to a router through a network adapter. The router then “routes” packets of data to and from each computing device. With this type of small private network, the router can in turn be connected to one or more larger private networks or a public network, such as the Internet. By sending and receiving messages through the router, each networked computing device may then communicate with computing devices outside of the private network. In this arrangement, the router serves as a “gateway” device that provides a gateway to and from the private network. Wireless gateway devices are often referred to as “access points.”
While this type of small or “home” network can provide enhanced utility for its member computing devices, even a small network can be very difficult for a non-technical person to set up and maintain.
IEEE 802.11, also known by the term Wi-Fi, denotes a set of Wireless LAN/WLAN standards developed by working group 11 of the IEEE LAN/MAN Standards Committee (IEEE 802). The 802.11 family currently includes six over-the-air modulation techniques that all use the same protocol. The most popular techniques are those defined by the b, a, g and n amendments to the original standard.
802.11b, 802.11g, and 802.11n standards use the 2.40 GHz (gigahertz) band, operating (in the United States) under Part 15 of the FCC Rules and Regulations. Because of this choice of frequency band, 802.11b and 802.11g equipment can encounter interference from microwave ovens, cordless telephones, Bluetooth devices, and other appliances using this same band.
802.11b and 802.11g—as well as 802.11n when using the 2.4 GHz band—divide the 2.4 GHz spectrum into 14 overlapping, staggered channels whose center frequencies are 5 megahertz (MHz) apart. The 802.11b, and 802.11g standards do not specify the width of a channel; rather, they specify the center frequency of the channel and a spectral mask for that channel. The spectral mask for 802.11b requires that the signal be attenuated by at least 30 dB from its peak energy at ±11 MHz from the center frequency, and attenuated by at least 50 dB from its peak energy at ±22 MHz from the center frequency. An example of such an energy signature associated with a given channel is shown in
In the USA, only channels 1-11 of the 14 available channels are used. As each channel is overlapped and staggered 5 MHz apart, the full range of energy signatures can be plotted as shown in
A common approach for configuring a wireless network is to operate the network on Channels 1, 6 or 11. These channels are each 25 MHz apart and so have the lowest amount of impact on each other, as is shown in
When considering the performance characteristics of a particular computer in a home network environment, users are typically concerned with factors such as:
The speed at which transfer can occur on a wireless network is gated by many factors, including but not limited to the signal strength between the laptop and router, and the amount of overlapping transmissions from other nearby wireless access points.
Generally speaking, improving the signal strength from a given wireless device is affected by proximity to the access point it is communicating with. A typical consumer can grasp this concept, and can locate their access point in a desirable location to improve signal strength. Determining the amount of overlapping transmissions from other nearby wireless devices, however, is more difficult and beyond the comprehension of an average consumer.
An embodiment of the invention includes a machine-implementable method of optimizing the performance of a wireless network includes collecting, with a first discovery component of the wireless network, a first set of information describing at least one transmission characteristic of each access point of a first set of at least one access points within a detection area of the first discovery component. Each access point of the first set transmits data over a respective channel of a set of channels. The method further includes determining, based on the first-set information, an optimal channel of the set of channels, the optimal channel having associated therewith the lowest probability of interference with the channels over which the access points of the first set are transmitting.
Preferred and alternative embodiments of the present invention are described in detail below with reference to the following figures:
An embodiment of the invention aids a proprietor of a wireless network in configuring the network by scanning the access points in the vicinity of the network and selecting the channel with the lowest probability of encountering overlapping transmissions.
Embodiments and elements thereof may incorporate or otherwise employ features described in U.S. Provisional Patent Application No. 60/634,432, filed Dec. 7, 2004, entitled “Network Management” and naming Steve Bush et al. as inventors, and U.S. patent application Ser. No. 11/297,809, filed on Dec. 7, 2005, entitled “Network Management” and naming Steve Bush et al. as inventors, which applications, along with U.S. Provisional Patent Application No. 60/789,522, filed Apr. 4, 2006, entitled “Network Management,” U.S. patent application Ser. No. 10/916,642, filed on Aug. 10, 2004, entitled “Service Licensing And Maintenance For Networks,” U.S. patent application Ser. No. 11/457,783, filed on Jul. 14, 2006, entitled “Network Device Management,” and U.S. patent application Ser. No. 11/457,763, filed on Jul. 14, 2006, entitled “Network Device Setup Utility,” are incorporated entirely herein by reference.
Various embodiments of the invention may be implemented within and by a wireless local-area, or otherwise small, network.
Each of these networked devices 103 communicates, either directly or indirectly, with a gateway device 105. In turn, the gateway device 105 typically will communicate with an external device or network. An external network may be another private network, or it may be a public network, such as the Internet 107. Thus, a gateway device is a device that can steer electronic data from one network to another network. Typically, a gateway device serves as a node on two incompatible networks (i.e., networks that use different communication protocol formats) and it can convert data from one network's communication protocol format into the other network's communication protocol format. As used herein, the term “small network” refers to a network made up of networked devices that each employ the same network address to communicate with the same gateway device, together with the gateway device itself.
The network devices 103 may be connected to the gateway device 105 using any suitable communication medium. For example, in the illustrated network 101, the desktop computers 103B are connected to the gateway device 105 through a hard-wired connection 109A (such as an Ethernet cable), while the laptop computer 103A is connected to the gateway device 105 through a IEEE 802.11 wireless connection 109B and the personal digital assistant 103C is connected to the gateway device 105 through a Bluetooth wireless connection 109C.
It should be appreciated that, as used throughout this application, the term “connect” and its derivatives (e.g., connection, connected, connects) includes both direct and indirect connections. Thus, with the network illustrated in
Typically, the gateway device 105 will be a router. As will be appreciated by those of ordinary skill in the art, a router routes data packets from the networked devices 103 to an external device or network. With some networks, however, the gateway device 105 alternately may be a computer performing router functions, a hub, a bridge, or “layer-3” switch. As will also be appreciated by those of ordinary skill in the art, the computing devices or “nodes” making up the network 101 can communicate with the gateway device 105 using one or more defined communication protocols, such as the Transmission Control Protocol (TCP) and the Internet Protocol (IP).
With these communication protocols, each computing device 103 and gateway device 105 in the network 101 can be assigned a logical address. For example, if the network 101 is connected to the Internet 107 through an Internet service provider, the Internet service provider can assign the gateway device 105 a logical Internet Protocol (IP) address. The Internet service provider may also provide the gateway device 105 with a block of logical Internet Protocol (IP) addresses for the gateway device 105 to reassign to each network device 103. Alternatively, the gateway device 105 can itself assign a range of logical Internet Protocol (IP) addresses to each network device 103, and then use a translation operation (e.g., a Network Address Translation (NAT) operation) to route data packets that it receives to the appropriate network device 103. This type of logical address typically is unrelated to the particular computing device to which it is assigned. Instead, a logical address identifies the relationship of that computing device to other computing devices in the network.
In addition to a logical address, each network device typically can also have a physical address. For example, most computing devices capable of communicating over a network, including routers, employ a network adapter with a media access control (MAC) address. This type of physical address is assigned to a network adapter according to standards (referred to as Project 802 or just 802 standards, which are incorporated entirely herein by reference) set forth by the Institute of Electrical and Electronic Engineers (IEEE). More particularly, these standards define a 48-bit and 64-bit physical address format for network devices. The first 14 bits of the address are assigned by the IEEE Registration Authority, and uniquely identify the manufacturer of the network adapter. The remaining bits are then assigned by the manufacturer to uniquely identify each network adapter produced by the manufacturer. Consequently, the physical address of a network adapter is unique across all networks unless manually changed by the user. The physical address is unique to the network adapter, and is independent of a computing device's relationship to other computing devices in a network. Thus, the physical address does not change over time or between uses in different networks.
A network may include both virtual devices and physical devices. Physical network devices can then include both computer devices and computing appliance devices. A “computer” may generally be characterized as a device that can be programmed to perform a number of different, unrelated functions. Examples of computers can thus include programmable personal computers, such as desktop computers and laptop computers. In addition, programmable media-purposed computers (e.g., “media adapters and servers”), network attached storage devices, programmable entertainment-purposed computers (e.g., video game consoles), some programmable personal digital assistants and some telephones (such as wireless “smart” telephones) may be characterized as computers in a network. A “computing appliance” then may generally be characterized as a device that is limited to primarily performing only specific functions. Examples of a computing appliance may thus include, for example, printers, cameras, telephones that exchange voice information in data packets (sometimes generically referred to as “Voice over Internet Protocol (VoIP) telephones or telephone adapters), digital video recorders, televisions, voice over Internet protocol (VoIP) adapters, print servers, media adapters, media servers, photo frames, data storage servers, routers, bridges and wireless access points.
As will be appreciated by those of ordinary skill in the art, there may be no clear defining line between “computer” network devices and “computing appliance” network devices in a network. For example, a sophisticated print server may be programmable to additionally or alternately function as a data storage server, while a programmable media-purposed computer or programmable personal digital assistant may have restricted functionality due to limited memory, input devices or output devices. Accordingly, as used herein, the term “computer” can refer to any network device that is capable of implementing a network management tool according to one or more aspects of the invention, such as a personal programmable computer. The term “computer appliance” then can refer to a network device that typically cannot implement a network management tool according to at least one aspect of the invention without additional augmentation. The term “computing device” is then used herein to include both computers and computing appliances.
With conventional networks located in a home, small office or other local environment, a network management tool according to various aspects of the invention can be implemented on a programmable personal computer, such as a desktop or laptop computer. A general description of this type of computer will therefore now be described.
An illustrative example of such a computer 201 as may be present in the network 101 described above is illustrated in
The processing unit 205 and the system memory 207 are connected, either directly or indirectly, through a bus 213 or alternate communication structure to one or more peripheral devices. For example, the processing unit 205 or the system memory 207 may be directly or indirectly connected to additional memory storage, such as the hard disk drive 215, the removable magnetic disk drive 217, the optical disk drive 219, and the flash memory card 221. The processing unit 205 and the system memory 207 also may be directly or indirectly connected to one or more input devices 223 and one or more output devices 225. The input devices 223 may include, for example, a keyboard, touch screen, a remote control pad, a pointing device (such as a mouse, touchpad, stylus, trackball, or joystick), a scanner, a camera or a microphone. The output devices 225 may include, for example, a monitor display, television, printer, stereo, or speakers.
Still further, the computing unit 203 can be directly or indirectly connected to one or more network interfaces 227 for communicating with a network. This type of network interface 227, also sometimes referred to as a network adapter or network interface card (NIC), translates data and control signals from the computing unit 203 into network messages according to a communication protocol, such as the Transmission Control Protocol (TCP), the Internet Protocol (IP), and the User Datagram Protocol (UDP). These protocols are well known in the art, and thus will not be described here in more detail. An interface 227 may employ any suitable connection agent for connecting to a network, including, for example, a wireless transceiver, a power line adapter, a modem, or an Ethernet connection.
It should be appreciated that one or more of these peripheral devices may be housed with the computing unit 203 and bus 213. Alternately or additionally, one or more of these peripheral devices may be housed separately from the computing unit 203 and bus 213, and then connected (either directly or indirectly) to the bus 213. Also, it should be appreciated that both computers and computing appliances may include any of the components illustrated in
It should be noted that, while a general description of a programmable personal computer was provided above, various aspects of the invention may be implemented on any desired device capable of supporting embodiments of the invention. For example, with some aspects of the invention, a network management tool may be implemented on special purposed programmable computers, such as a programmable media or entertainment-purposed computers, or personal digital assistants. Accordingly, the above description of a programmable personal computer should be understood as illustrative rather than limiting.
A computing appliance may have any combination of the components of the computer 201 discussed above. More typically, however, a computing appliance can be simpler to optimize the performance of a specific function, and thus may have only a subset of these components. For example, a computing appliance may have only a computing unit 203, an input device 223 or an output device 225, and a network interface 227. As will be apparent from the following description, however, a computing appliance will have sufficient computing resources to implement a desired embodiment of the invention in order to provide information to or receive information from a client operating on a separate computing device.
As earlier alluded to, the conventional wisdom when configuring a wireless network is to select channels 1, 6 or 11. As these channels are in the center and at both extremes of the frequency spectrum, their energies overlap less than any other combination of channels. This guideline assumes, however, an ideal situation where all neighboring access points adhere to the same convention. In real-world situations this is rarely the case. More often than not, there may be neighboring access points on any random collection of channels other than 1, 6, or 11. It should also be noted that concurrent activity on overlapping channels causes significant degradation in performance over any one of such channels.
An embodiment of the invention employs an algorithm to determine the potential for overlapping transmissions that may interfere with a given network. As is discussed in further detail herein, an embodiment causes an access point or other capable polling device of a network to scan for all broadcasting access points in the vicinity of the network. It evaluates each access point by its signal strength and channel spread impact and calculates a density array that characterizes the entire channel-frequency spectrum. A final pass of the density array is performed to determine the channel with the lowest potential for interfering overlap.
More specifically, and referring now to
At a block 610, the creation of a density array 710 (
At a block 620, information is gathered on all detectable access points. For example, one or more devices 103, 105 of the network 101 can detect, in a conventional manner, all access points broadcasting in the general vicinity of the network 101. Of specific interest in this detection/gathering function is the channel over which each access point is transmitting and the signal strength of such transmissions as measured at the detecting device 103, 105.
For purposes of the following illustrative example, and referring to Table 1 below, consider a case in which there are only 3 access points detectable by the detecting device 103, 105 and that would thus presumptively impact the wireless operation of network 101. For simplification of the example, and as a proxy for the actual Received Signal Strength Indication (RSSI) dBM value, we can assign values of 1-5 to the signal strength where 1==poor and 5==excellent:
At a block 630, for each access point found, the associated impact is recorded by calculating and assigning to the density array 710 weighted impact-value data. In an embodiment, the impact-value data is calculated using the following equation:
Value=RSSI*DM
where “RSSI” is the signal strength of the access point and “DM” is a distance modifier applied to weight partitions according to their distance from the center of a corresponding channel. In the illustrated example, the inner 5 MHz partitions representing the frequency ranges closest to the frequency center of the channel are assigned a DM of 1.0 (i.e., 100%), while the outer partitions representing the frequency ranges farthest from the frequency center of the channel are assigned a DM of 0.75 (i.e., 75%).
As such, and referring to
In a similar manner, and referring to
Once the density array is filled in, at a block 640, the optimal channel on which the network 101 should operate is determined. In turn, to determine the optimal channel, a set of sums 760 of the weighted impact values associated with partitions of each respective frequency range is determined, as sequentially illustrated in
An embodiment of the invention described above contemplates measuring the optimal channel for operating a single wireless device. For a given home network, a user might roam from room to room with their laptop, so a single test involving one device and the access point might not yield the optimal results for all devices on the network.
As such, an embodiment contemplates concurrently performing density analyses based on information gathered by all devices in the network having detection capability. Each density array can be reported back to a master PC or other network device, which can combine (via superimposition, for example) or otherwise analyze the arrays to determine the best available channel for the network as a whole.
While embodiments of the invention have been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as described herein. For example, while examples in this document generally refer to channels in the 2.4 GHz spectrum, it should be understood that one or more embodiments of the invention are applicable to 5 GHz or any spectrum that is sub-dividable into channels. Additionally, an embodiment of the invention described elsewhere herein calculates “potential” channel conflict/overlap, not actual conflict, based at least in part on the signal strength of access points. Signal strength alone is not always an indicator of interference as there may be no traffic across the access point at the time such access point is analyzed. As such, an embodiment includes performing period speed tests on a newly selected channel, adjusting channels, and taking new measurements to determine best throughput.
This application claims priority from U.S. Provisional Patent Application No. 60/949,622, filed Jul. 13, 2007, entitled “METHOD FOR OPTIMIZING A WIRELESS NETWORK BY SURVEYING WIRELESS CHANNEL DENSITY,” which is hereby incorporated by reference in its entirety as if fully set forth herein.
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