A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures.
The following detailed description is merely illustrative in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any express or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
The invention may be described herein in terms of functional and/or logical block components and various processing steps. It should be appreciated that such block components may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. For example, an embodiment of the invention may employ various integrated circuit components, e.g., radio-frequency (RF) devices, memory elements, digital signal processing elements, logic elements, lookup tables, or the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that the present invention may be practiced in conjunction with any number of data transmission protocols and that the system described herein is merely one exemplary application for the invention.
For the sake of brevity, conventional techniques related to signal processing, data transmission, signaling, network control, the 802.11 family of specifications, wireless networks, RFID systems and specifications, and other functional aspects of the system (and the individual operating components of the system) may not be described in detail herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent example functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical embodiment.
Without loss of generality, in the illustrated embodiment, many of the functions usually provided by a traditional access point (e.g., network management, wireless configuration, etc.) and/or traditional RFID readers (e.g., data collection, RFID processing, etc.) are concentrated in a corresponding RF switch. It will be appreciated that the present invention is not so limited, and that the methods and systems described herein may be used in conjunction with traditional access points and RFID readers or any other device that communicates via RF channels.
The present invention relates a method of determining and visualizing the state of a RF network using a set of key performance indicators (“performance indicators,” or simply KPI).
Referring to
A number of RFID tags (or simply “tags”) 104, 107 are distributed throughout the environment. These tags are read by a number of RFID readers (or simply “readers”) 108 having one or more associated antennas 106 provided within the environment. The term “tag” refers, in general, to any RF element that can be communicated with and has an ID that can be read by another component. Readers 108, each of which may be stationary or mobile, are suitably connective via wired or wireless data links to a RF switch 110.
A particular AP 120 may have a number of associated MUs 130. For example, in the illustrated topology, MUs 130(a) and 130(b) are associated with AP 120(a), while MU 130(c) is associated with AP 120(b). One or more APs 120 may be coupled to a single switch 110, as illustrated.
RF Switch 110 determines the destination of packets it receives over network 104 and 101 and routes those packets to the appropriate AP 120 if the destination is an MU 130 with which the AP is associated. Each WS 110 therefore maintains a routing list of MUs 130 and their associated APs 130. These lists are generated using a suitable packet handling process as is known in the art. Thus, each AP 120 acts primarily as a conduit, sending/receiving RF transmissions via MUs 130, and sending/receiving packets via a network protocol with WS 110. AP 120 is typically capable of communicating with one or more MUs 130 through multiple RF channels. This distribution of channels varies greatly by device, as well as country of operation. For example, in one U.S. embodiment (in accordance with 802.11(b)) there are fourteen overlapping, staggered channels, each centered 5 MHz apart in the RF band.
A particular RFID reader 108 may have multiple associated antennas 106. For example, as shown in
In general, RFID tags (sometimes referred to as “transponders”) may be classified as either active, passive, or semi-active. Active tags are devices that incorporate some form of power source (e.g., batteries, capacitors, or the like) and are typically always “on,” while passive tags are tags that are exclusively energized via an RF energy source received from a nearby antenna. Semi-active tags are tags with their own power source, but which are in a standby or inactive mode until they receive a signal from an external RFID reader, whereupon they “wake up” and operate for a time just as though they were active tags. While active tags are more powerful, and exhibit a greater range than passive tags, they also have a shorter lifetime and are significantly more expensive. Such tags are well known in the art, and need not be described in detail herein.
Each antenna 106 has an associated RF range (or “read point”) 116, which depends upon, among other things, the strength of the respective antenna 106. The read point 116 corresponds to the area around the antenna in which a tag 104 may be read by that antenna, and may be defined by a variety of shapes, depending upon the nature of the antenna (i.e., the RF range need not be circular or spherical as illustrated in
It is not uncommon for RF ranges or read points to overlap in real-world applications (e.g., doorways, small rooms, etc.). Thus, as shown in
As described in further detail below, switch 102 includes hardware, software, and/or firmware capable of carrying out the functions described herein. Thus, switch 102 may comprise one or more processors accompanied by storage units, displays, input/output devices, an operating system, database management software, networking software, and the like. Such systems are well known in the art, and need not be described in detail. Switch 102 may be configured as a general purpose computer, a network switch, or any other such network host. In a preferred embodiment, controller 102 is modeled on a network switch architecture but includes RF network controller software (or “module”) whose capabilities include, among other things, the ability to allow configure and monitor readers 108 and antennas 106.
RF switch 110 allows multiple read points 116 to be logically combined, via controller 102, within a single read point zone (or simply “zone”). For example, referring to
As mentioned above, the present invention relates a method of determining and visualizing the state of a RF network (such as that shown in
In a particular embodiment, five performance indicators are defined as a factory default: KPI-I through KPI-V. This is illustrated conceptually in
In the illustrated embodiment, the first performance indicator 202 (KPI-I) is a metric associated with RF coverage. In one embodiment KPI-I includes a set of numbers 212 associated with RF coverage in the RF network (KPI-I(a)-(i)). That is, KPI-I is computed from this set of numbers, wherein the numbers relate to measured characteristics of the network or the components disposed therein. In one embodiment, KPI-I(a) is equal to the number of system components that are operational and/or configured—i.e., 802.11 APs, 802.11 radios, RFID readers, RFID antennas, WiMAX APs, and WiMax Radios, and any other components as may be appropriate. KPI-I(b) is equal to the number of system components with operational and/or configured channels. KPI-I(c) is associated with the number of system components with operational and/or configured power. KPI-I(d) is equal to the number of operational and/or configured data rates. KPI-I(e) is equal to the number of MUs transfer at maximum bit speed, number of tags seen, channel health as seen per tag read, etc. KPI-I(f) is equal to the number of switch level retries and collision count per bucket. KPI-I(g) is equal to switch level average 802.11 RSSI per bucket/channel health per tag read. KPI-I(h) is equal to the average bit speed and how close it is to the maximum rate possible for the various MUs. KPI-I(i) is equal to the average 802.11 bit speed/RFID tag read rate/collision rate as per predicted and/or current heat map of the facility in which the components are deployed. It will be appreciated that these specific metrics for KPI-I(a)-(i).
The second performance indicator 204 (KPI-II) is a metric associated with load balancing in the RF network. In a specific embodiment, KPI-II includes a set of three numbers 214, KPI-II(a)-(c), where KPI-II(a) is associated with the balancing of APs across switches, KPI-II(b) is associated with the balancing of MUs across switches, and KPI-II(c) is associated with the number of MUs balanced across APs. This enables the user to add changes in the network to provide better RF coverage as load increases.
The third performance indicator 206 (KPI-III) is a metric associated with security threat level. In a specific embodiment, KPI-III includes a set of six numbers 216, KPI-III(a)-(f), where KPI-III(a) is associated with the number of rogue APs and/or RFID readers or RF devices managed by the RF switch, KPI-III(b) is associated with the number of IDS events (sniffer attacks, denial-of-service attacks, etc.), KPI-III(c) is associated with the amount of RF slippage currently and/or planned, KPI-III(d) is associated with the location of one or more intruders, KPI-III(e) is associated with the number of users connected to the network, and KPI-III(f) is associated with the number of incorrect password requests. This allow the user to determine whether some action must be taken to secure the network.
The fourth performance indicator 208 (KPI-IV) is a metric associated with redundancy (i.e., a redundancy quotient, or resiliency quotient). In a specific embodiment, KPI-IV includes a set of two numbers 218: KPI-IV(a), which is associated with the status of members of a particular cluster within the network (e.g., how many are reachable, how many are standbys), and KPI-IV(b), which is associated with the self-healing status of the radios, RFID antennas, WiMax radios, etc. This enables the user to determine whether the network has enough “resiliency” to tolerate failures, and what the thresholds for action should be.
The fifth performance indicator 210 (KPI-V) is a metric associated with network utilization. In a specific embodiment, KPI-V includes a set of two numbers 220: KPI-V(a), which is associated with the number of switches, the capacity of the switches, and the current usage; and KPI-V(b), which is associated with the number, capacity, and current usage of radios and/or antennae.
The values of the performance indicators may be integers, real numbers, or any suitable numeric value. The performance indicators may be normalized (e.g., to a number between 0-100, or 0.0-1.0), or may an unbounded numeric value. Each performance indicator is a suitable function of the set of numbers it comprises. For example, KPI-II comprises three numbers, each related to the number of components that are balanced among other components of the system. In each case, the balancing may be assigned a number ranging from zero (not balanced) and 100 (fully balanced). A weighting function or linear equation may then be applied to each of these three numbers to produce a given numeric value of KPI-II, which itself ranges between 0 and 100. The selection of functions for each of the performance indicators may be selected in accordance with known principles and to achieve any particular design goal.
In accordance with another aspect of the present invention, the various KPI values are presented in visual form for review by an administrator, user, or other operator of the system. This visual representation may be produced on any convenient display that can access RF switch 110 of the network—e.g., via a browser accessing a webpage produced using the data residing within memory 200.
Referring to
In yet another embodiment, the system may be configured such that a suitable alarm is produced and communicated to a user when a particular state of the performance indicators occurs—e.g., if a particular performance indicator drops below a certain level, or if the combination of multiple performance indicators drops achieves a particular value or range of values. The administrator may be allowed to set up any arbitrary rules for generating such alarms.
It should be appreciated that the example embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.