US20100316036A1 - Wireless network roaming timer method and apparatus - Google Patents
Wireless network roaming timer method and apparatus Download PDFInfo
- Publication number
- US20100316036A1 US20100316036A1 US12/868,010 US86801010A US2010316036A1 US 20100316036 A1 US20100316036 A1 US 20100316036A1 US 86801010 A US86801010 A US 86801010A US 2010316036 A1 US2010316036 A1 US 2010316036A1
- Authority
- US
- United States
- Prior art keywords
- access point
- mobile station
- timer
- roaming
- processor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 54
- 230000005540 biological transmission Effects 0.000 claims description 6
- 230000006870 function Effects 0.000 description 7
- 238000004891 communication Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
- H04W36/304—Reselection being triggered by specific parameters by measured or perceived connection quality data due to measured or perceived resources with higher communication quality
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W8/00—Network data management
- H04W8/02—Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
Definitions
- the present invention relates generally to computer networks, and more specifically to wireless networks.
- Wireless networks typically include mobile stations and access points.
- a mobile station may “associate” with an access point (referred to herein as the “current access point”) to communicate with other devices on the network.
- Mobile stations may move about while access points are typically stationary. If a mobile station moves around in an area covered by multiple access points, the mobile station may “disassociate” from the current access point and associate with another. The process of disassociation and association may be repeated any number of times, as the mobile station moves about.
- a mobile station may periodically communicate with a variety of access points, including access points other than the current access point.
- access points including access points other than the current access point.
- FIG. 1 shows a diagram of a wireless network
- FIGS. 2 and 3 show flowcharts in accordance with various embodiments of the present invention
- FIG. 4 shows a plot with various received signal strength indicator thresholds
- FIG. 5 shows a system diagram in accordance with various embodiments of the present invention.
- FIG. 1 shows a diagram of a wireless network.
- Wireless network 100 includes mobile station 102 and access points (AP) 110 , 120 , and 130 .
- wireless network 100 is a wireless local area network (WLAN).
- access points 110 , 120 , and 130 , and mobile station 102 may operate in compliance with a wireless network standard such as ANSI/IEEE Std. 802.11, 1999 Edition, although this is not a limitation of the present invention.
- Mobile station 102 is shown communicating with access point 110 using signal 112 , access point 120 using signal 122 , and access point 130 using signal 132 .
- Mobile station 102 may associate with one of the access points for data communications, and may also communicate with other access points to decide if it should end the current association and associate with another access point. For example, mobile station 102 may be associated with access point 110 .
- signal 112 allows data to be communicated between mobile station 102 and access point 110 .
- Mobile station 102 may periodically “roam,” or “attempt to roam.”
- the terms “roam” and “attempt to roam” refer to the actions taken by a mobile station when deciding whether to end a current association (“disassociate”) and make a new association with a different access point.
- roaming occurs when a mobile station performs a scan of available access points and decides to disassociate with the current access point and re-associate with a different access point.
- an attempt to roam occurs when a mobile station performs a scan of available access points, and does not disassociate with the current access point. This may occur when the mobile station scans to see if a “better” access point is available, and decides to maintain the current association rather than disassociate with the current access point.
- Roaming, or attempting to roam may reduce the data throughput of the current association. For example, if mobile station 102 attempts to roam to check the availability of access points 120 and 130 , the data throughput of the current association with access point 110 may be reduced.
- Mobile station 102 includes roaming timer 104 .
- a roaming timer is a timer that may be used to put off an attempt to roam based on various criteria. For example, if the current association is perceived to be of “high quality,” roaming timer 104 may be set to a relatively large value, and any roaming attempts by mobile station 102 may be delayed, or “put off,” in time until the timer expires. In some embodiments, the timer may be repeatedly set or reset to continually delay any attempts to roam, or to force an attempt to roam immediately. Further, the roaming timer may be set to any value based on any criteria. The type or amount of criteria used to the set the timer should not be considered a limitation of the present invention.
- Roaming timer 104 may be implemented using any of many different mechanisms.
- roaming timer 104 may be a hardware timer or a software timer.
- multiple hardware timers are utilized, where each is set to either the same or different values.
- multiple software timers are utilized, where each is set to either the same or different values.
- a roaming attempt may occur when one of the multiple timers times out, or when all of the multiple timers times out.
- the perceived quality of a current association may be defined by any parameter, metric, or combination of parameters or metrics. Various embodiments using different parameters and metrics are described below with reference to the remaining figures.
- FIG. 2 shows a flowchart in accordance with various embodiments of the present invention.
- method 200 may be used to decide when to attempt to roam in a wireless network.
- method 200 or portions thereof, is performed by a wireless network interface, a processor, or an electronic system, embodiments of which are shown in the various figures.
- Method 200 is not limited by the particular type of apparatus, software element, or person performing the method.
- the various actions in method 200 may be performed in the order presented, or may be performed in a different order. Further, in some embodiments, some actions listed in FIG. 2 are omitted from method 200 .
- Method 200 is shown beginning at block 210 in which a first metric is compared to a first threshold; and in block 220 , a timer is conditionally set to a first value.
- the timer referred to in block 220 operates as a roaming timer, such as roaming timer 104 ( FIG. 1 ).
- the device performing method 200 may attempt to roam at various intervals based, at least in part, on the values to which the timer is set.
- Utilizing a roaming timer to put off a roaming attempt may be useful in many different operational scenarios. For example, if during a current association with an access point, a mobile station enjoys a “high quality” connection, periodic attempts to roam may not be the most efficient use of the mobile station's resources. On the other hand, if a mobile station has a lower quality connection, the interval between roaming attempts may be modified to make more efficient use of the mobile station's resources.
- a second metric is compared to a second threshold, and in block 240 , the timer is conditionally set to a second value.
- Various embodiments of the present invention are not limited to two metrics, two thresholds, and two timer values as shown in FIG. 2 . For example, in some embodiments, many more than two metrics are utilized. Further, in some embodiments, a single metric is used, and the single metric is compared against multiple thresholds. The result of the comparison with multiple thresholds may result in setting a roaming timer with one of many different possible timer values.
- an attempt to roam is made when the timer expires.
- the timer runs in the “background.”
- the hardware may be adapted to decrement a counter every clock cycle or every N clock cycles.
- the counter may perform as a roaming timer when loaded with a timer value, and the counter is decremented in the background.
- the counter is only decremented when enabled, and various method embodiments of the present invention not only set the timer, but also enable and disable the timer.
- the roaming attempt may be initiated in one of many different ways.
- the hardware timer may cause a processor interrupt, or may set a bit in a status register. The present invention is not limited in this respect.
- the software timer may be implemented as a software counter that is decremented in the background.
- a software routine may be scheduled to run every second, or every 100 milliseconds, and each time the software routine runs, it may decrement the counter that functions as the roaming timer.
- the software counter may be enabled or disabled in support of the operation of the roaming timer. The interval between successive decrement operations of the counter is not a limitation of the present invention.
- method 200 may be performed periodically. For example, method 200 may run every second or every ten seconds in a mobile station, such as mobile station 102 ( FIG. 1 ). As a result, roaming attempts may be put off indefinitely, or may be performed at intervals defined, at least in part, by the timer values.
- FIG. 3 shows a flowchart in accordance with various embodiments of the present invention.
- method 300 may be used to decide when to attempt to roam in a wireless network.
- method 300 or portions thereof, is performed by a wireless network interface, a processor, or an electronic system, embodiments of which are shown in the various figures.
- Method 300 is not limited by the particular type of apparatus, software element, or person performing the method.
- the various actions in method 300 may be performed in the order presented, or may be performed in a different order. Further, in some embodiments, some actions listed in FIG. 3 are omitted from method 300 .
- Method 300 is shown beginning at block 305 in which a first metric is compared to a threshold.
- the metric includes a determination of how many “beacons” have been missed.
- a beacon is a packet or frame periodically transmitted by an access point. If many beacons have been missed by a mobile station, this may be indicative of a poor quality connection between the mobile station and the access point. As shown in FIG. 3 , if many beacons have been missed, an attempt to roam may be performed at 310 .
- the attempt to roam at 310 may be performed by resetting a roaming timer, or by performing an attempt to roam regardless of the state of the roaming timer.
- the number of missed beacons used as a threshold in block 305 may be set to any threshold. In some embodiments, if more than 50% of beacons are missed, an attempt to roam is performed at block 310 . In other embodiments, if more than 60% of beacons are missed, an attempt to roam is performed at block 310 .
- the particular threshold used in block 305 is not a limitation of the present invention.
- a percentage of “retries” is checked, and if it is not high, then method 200 ends with a determination to not attempt roaming at block 320 .
- a “retry” corresponds to a packet or frame that is retransmitted because of a previously unsuccessful attempt at transmission.
- the percentage of retries represents a metric that can be either gathered or calculated, and the number to which the percentage is compared represents a threshold.
- the actual percentage used as a threshold is not a limitation of the present invention.
- the remaining decision blocks compare a metric against a threshold, and conditionally enter one of four states ( 330 , 340 , 350 , or 360 ) depending on the outcome of the decisions. Although three decision blocks and four states are shown, any number of decision blocks and states may be implemented without departing from the scope of the present invention.
- Decision block 325 compares a current data rate to a threshold.
- the threshold is the lowest data rate available. For example, in some embodiments, the mobile station will reduce the data rate as the distance to the access point increases, or as the received signal strength decreases. If the current data rate corresponds to the lowest rate available, then if the signal degrades further, the mobile station may be forced to disassociate. If the current rate is low, then method 300 enters STATE A (block 330 ) where the roaming timer is set to 10 seconds.
- Block 330 is referred to as a “state” in part because, if in subsequent invocations of method 300 , STATE A is re-entered, then the timer is not necessarily set to 10 seconds again. For example, assuming that method 300 is performed once a second, and each time it is performed block 330 is reached, the first time block 330 is reached, STATE A will be entered, and the roaming timer will be set to 10 seconds. The second time block 330 is reached, the roaming timer will not be set, because STATE A has remained the active state. In this example, method 300 will be performed 10 times, block 330 will be reached each time, the roaming timer will expire, and an attempt to roam will be performed.
- an average received signal strength indicator is compared against a threshold.
- the RSSI is the metric
- the “current rate threshold” is the threshold to which the metric is compared. If the average RSSI is less than the current rate threshold, then block 340 is reached, and if the current state is not STATE B, STATE B is entered, and the roaming timer is set to two minutes. If block 340 was reached the last time that method 300 was performed, then the current state remains STATE B, and the timer is not necessarily set. If block 340 is reached each time method 300 is performed over a two minute period, the timer will expire, and an attempt to roam will be performed.
- FIG. 4 An example of a “current rate threshold” is shown in FIG. 4 at 410 .
- the current rate threshold may vary as a function of the current rate.
- Four current rate threshold values are shown in FIG. 4 , each corresponding to a different rate. Any number of current rate thresholds may exist without departing from the scope of the present invention. In some embodiments, the thresholds are different as shown in FIG. 4 , and in other embodiments, the thresholds are the same.
- an average received signal strength indicator is compared against a second threshold.
- the RSSI is the metric
- the “good threshold” is the threshold to which the metric is compared. If the average RSSI is less than the good threshold, then block 350 is reached, and if the current state is not STATE C, STATE C is entered, and the roaming timer is set to four minutes. If block 350 was reached the last time that method 300 was performed, then the current state remains STATE C, and the timer is not necessarily set. If block 350 is reached each time method 300 is performed over a four minute period, the timer will expire, and an attempt to roam will be performed.
- block 360 is reached, and if the current state is not STATE D, STATE D is entered, and the roaming timer is set to fifteen minutes. If block 360 was reached the last time that method 300 was performed, then the current state remains STATE D, and the timer is not necessarily set. If block 360 is reached each time method 300 is performed over a fifteen minute period, the timer will expire, and an attempt to roam will be performed.
- the good threshold does not vary as a function of the current rate, but this is not a limitation of the present invention.
- the good threshold may vary as a function of current rate, similar to the current rate threshold shown at 410 .
- Method 300 allows a mobile station to measure a “perceived quality” of a current connection.
- the perceived quality of the connection is based on various metrics as shown in method 300 .
- the roaming timer is set to a relatively high value when the perceived quality is high. Also in some embodiments, the roaming timer is set to a relatively low value when the perceived quality is lower.
- FIG. 4 shows a plot with various received signal strength indicator thresholds.
- the vertical axis corresponds to thresholds for comparison against the received signal strength indicator (RSSI).
- the horizontal axis represents data rates.
- the current rate threshold is a function of the current data rate, and the good threshold is constant. In some embodiments, more than two types of thresholds are utilized, and in some embodiments, more than one threshold is a function of data rate.
- FIG. 5 shows a system diagram in accordance with various embodiments of the present invention.
- Electronic system 500 includes antenna 510 , radio interface 520 , physical layer (PHY) 530 , media access control layer (MAC) 540 , processor 560 , roaming timer 550 , and memory 570 .
- Electronic system 500 also includes host processor 580 and host memory 590 .
- system 500 sends and receives signals using antenna 510 , and the signals are processed by the various elements shown in FIG. 5 .
- Antenna 510 may be a directional antenna or an omni-directional antenna.
- the term omni-directional antenna refers to any antenna having a substantially uniform pattern in at least one plane.
- antenna 510 may be an omni-directional antenna such as a dipole antenna, or a quarter wave antenna. Also for example, in some embodiments, antenna 510 may be a directional antenna such as a parabolic dish antenna or a Yagi antenna.
- Host processor 580 is coupled to processor 560 by bus 565 .
- the blocks shown to the left of bus 565 may be an apparatus such as a wireless network interface, and the blocks shown to the right of bus 565 may be an apparatus or system such as a laptop computer.
- the wireless interface may be on a card that plugs into the laptop computer, or may be a wireless interface that is integral with the computer.
- bus 565 represents a communications bus such as a peripheral component interconnect (PCI) bus, however this is not a limitation of the present invention.
- PCI peripheral component interconnect
- Radio interface 520 may include circuitry to support the transmission and reception of radio frequency (RF) signals.
- radio interface 520 includes an RF receiver to receive signals and perform “front end” processing such as low noise amplification (LNA), filtering, frequency conversion or the like.
- radio interface 520 includes circuits to support frequency up-conversion, and an RF transmitter. The invention is not limited by the contents or function of radio interface 520 .
- Physical layer (PHY) 530 may be any suitable physical layer implementation.
- PHY 530 may be a circuit block that implements a physical layer that complies with the IEEE 802.11 standard or other standard. Examples include, but are not limited to, direct sequence spread spectrum (DSSS), frequency hopping spread spectrum (FHSS), and orthogonal frequency division multiplexing (OFDM).
- Media access control layer (MAC) 540 may be any suitable media access control layer implementation.
- MAC 540 may be implemented in software, or hardware or any combination thereof.
- MAC 540 may be implemented in software that is partially executed by processor 560 and partially executed by host processor 580 .
- Roaming timer 550 may be a timer utilized to put off a decision to roam, such as roaming timer 104 ( FIG. 1 ). Roaming timer 550 may be implemented in hardware or software or any combination. In some embodiments, roaming timer 550 is set to various values, and when the timer expires, an attempt to roam is performed. For example, methods such as method 200 ( FIG. 2 ) and method 300 ( FIG. 3 ) may be used to compare metrics to thresholds and conditionally set roaming timer 550 . In some embodiments, roaming timer 550 may be coupled to (or implemented by) processor 560 . In other embodiments, roaming timer 550 may be coupled to (or implemented by) host processor 580 .
- Processor 560 may be a processor that sets roaming timer 550 based, at least in part, on comparisons between metrics and thresholds. For example, processor 560 may perform methods such as method 200 ( FIG. 2 ) or method 300 ( FIG. 3 ).
- Processor 560 represents any type of processor, including but not limited to, a microprocessor, a digital signal processor, a microcontroller, or the like.
- processor 560 does not exist, and dedicated digital logic or other hardware is coupled to roaming timer 550 .
- the dedicated digital logic or other hardware may set roaming timer 550 based, at least in part, on comparisons between metrics and thresholds.
- Memory 570 represents an article that includes a machine readable medium.
- memory 570 represents a random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), read only memory (ROM), flash memory, or any other type of article that includes a medium readable by processor 560 .
- Memory 570 can store instructions for performing the execution of the various method embodiments of the present invention.
- Host processor 580 may be any processor capable of communication with processor 560 over bus 565 .
- Host processor 580 represents any type of processor, including but not limited to, a microprocessor, a personal computer, a workstation, or the like.
- host processor 580 may set a roaming timer.
- host processor 580 may implement MAC 540 or a portion of MAC 540 in a software driver or other software.
- a MAC (or a portion thereof) implemented in processor 580 may include one or more roaming timers as discussed herein.
- Host memory 590 represents an article that includes a machine readable medium.
- host memory 590 represents any one or more of the following: a hard disk, a floppy disk, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), read only memory (ROM), flash memory, CDROM, or any other type of article that includes a medium readable by host processor 580 .
- RAM random access memory
- DRAM dynamic random access memory
- SRAM static random access memory
- ROM read only memory
- flash memory CDROM, or any other type of article that includes a medium readable by host processor 580 .
- Systems represented by the various foregoing figures can be of any type. Examples of represented systems include computers (e.g., desktops, laptops, handhelds, servers, tablets, web appliances, routers, etc.), wireless communications devices (e.g., cellular phones, cordless phones, pagers, personal digital assistants, etc.), computer-related peripherals (e.g., printers, scanners, monitors, etc.), entertainment devices (e.g., televisions, radios, stereos, tape and compact disc players, video cassette recorders, camcorders, digital cameras, MP3 (Motion Picture Experts Group, Audio Layer 3) players, video games, watches, etc.), and the like.
- computers e.g., desktops, laptops, handhelds, servers, tablets, web appliances, routers, etc.
- wireless communications devices e.g., cellular phones, cordless phones, pagers, personal digital assistants, etc.
- computer-related peripherals e.g., printers, scanners, monitors, etc.
- entertainment devices
- Roaming timers, processors, wireless network interfaces, and other embodiments of the present invention can be implemented in many ways. In some embodiments, they are implemented in electronics as part of mobile stations for use in wireless networks. In some embodiments, design descriptions of the various embodiments of the present invention are included in libraries that enable designers to include them in custom or semi-custom designs. For example, any of the disclosed embodiments can be implemented in a synthesizable hardware design language, such as VHDL or Verilog, and distributed to designers for inclusion in standard cell designs, gate arrays, or the like. Likewise, any embodiment of the present invention can also be represented as a hard macro targeted to a specific manufacturing process.
Abstract
A mobile station in a wireless network includes a roaming timer. The roaming timer is set based on various criteria, and when the roaming timer expires, an attempt to roam is performed.
Description
- This application is a divisional application of U.S. application Ser. No. 10/675,007 filed on Sep. 30, 2003.
- The present invention relates generally to computer networks, and more specifically to wireless networks.
- Wireless networks typically include mobile stations and access points. A mobile station may “associate” with an access point (referred to herein as the “current access point”) to communicate with other devices on the network. Mobile stations may move about while access points are typically stationary. If a mobile station moves around in an area covered by multiple access points, the mobile station may “disassociate” from the current access point and associate with another. The process of disassociation and association may be repeated any number of times, as the mobile station moves about.
- In order to decide whether or not to disassociate from the current access point or associate with a different access point, a mobile station may periodically communicate with a variety of access points, including access points other than the current access point. When a mobile station communicates with access points other than the current access point, the data throughput between the mobile station and the current access point may suffer.
-
FIG. 1 shows a diagram of a wireless network; -
FIGS. 2 and 3 show flowcharts in accordance with various embodiments of the present invention; -
FIG. 4 shows a plot with various received signal strength indicator thresholds; and -
FIG. 5 shows a system diagram in accordance with various embodiments of the present invention. - In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the spirit and scope of the invention. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled. In the drawings, like numerals refer to the same or similar functionality throughout the several views.
-
FIG. 1 shows a diagram of a wireless network.Wireless network 100 includesmobile station 102 and access points (AP) 110, 120, and 130. In some embodiments,wireless network 100 is a wireless local area network (WLAN). For example,access points mobile station 102 may operate in compliance with a wireless network standard such as ANSI/IEEE Std. 802.11, 1999 Edition, although this is not a limitation of the present invention. -
Mobile station 102 is shown communicating withaccess point 110 usingsignal 112,access point 120 usingsignal 122, andaccess point 130 usingsignal 132.Mobile station 102 may associate with one of the access points for data communications, and may also communicate with other access points to decide if it should end the current association and associate with another access point. For example,mobile station 102 may be associated withaccess point 110. When a current association exists betweenmobile station 102 andaccess point 110,signal 112 allows data to be communicated betweenmobile station 102 andaccess point 110. -
Mobile station 102 may periodically “roam,” or “attempt to roam.” As used herein, the terms “roam” and “attempt to roam” refer to the actions taken by a mobile station when deciding whether to end a current association (“disassociate”) and make a new association with a different access point. In some instances, roaming occurs when a mobile station performs a scan of available access points and decides to disassociate with the current access point and re-associate with a different access point. In other instances, an attempt to roam occurs when a mobile station performs a scan of available access points, and does not disassociate with the current access point. This may occur when the mobile station scans to see if a “better” access point is available, and decides to maintain the current association rather than disassociate with the current access point. - Roaming, or attempting to roam, may reduce the data throughput of the current association. For example, if
mobile station 102 attempts to roam to check the availability ofaccess points access point 110 may be reduced. -
Mobile station 102 includesroaming timer 104. A roaming timer, as defined herein, is a timer that may be used to put off an attempt to roam based on various criteria. For example, if the current association is perceived to be of “high quality,”roaming timer 104 may be set to a relatively large value, and any roaming attempts bymobile station 102 may be delayed, or “put off,” in time until the timer expires. In some embodiments, the timer may be repeatedly set or reset to continually delay any attempts to roam, or to force an attempt to roam immediately. Further, the roaming timer may be set to any value based on any criteria. The type or amount of criteria used to the set the timer should not be considered a limitation of the present invention. - Roaming
timer 104 may be implemented using any of many different mechanisms. For example, roamingtimer 104 may be a hardware timer or a software timer. In some embodiments, multiple hardware timers are utilized, where each is set to either the same or different values. In other embodiments, multiple software timers are utilized, where each is set to either the same or different values. A roaming attempt may occur when one of the multiple timers times out, or when all of the multiple timers times out. - The perceived quality of a current association may be defined by any parameter, metric, or combination of parameters or metrics. Various embodiments using different parameters and metrics are described below with reference to the remaining figures.
-
FIG. 2 shows a flowchart in accordance with various embodiments of the present invention. In some embodiments,method 200 may be used to decide when to attempt to roam in a wireless network. In some embodiments,method 200, or portions thereof, is performed by a wireless network interface, a processor, or an electronic system, embodiments of which are shown in the various figures.Method 200 is not limited by the particular type of apparatus, software element, or person performing the method. The various actions inmethod 200 may be performed in the order presented, or may be performed in a different order. Further, in some embodiments, some actions listed inFIG. 2 are omitted frommethod 200. -
Method 200 is shown beginning atblock 210 in which a first metric is compared to a first threshold; and inblock 220, a timer is conditionally set to a first value. The timer referred to inblock 220 operates as a roaming timer, such as roaming timer 104 (FIG. 1 ). Rather than only attempting to roam at periodic intervals, thedevice performing method 200 may attempt to roam at various intervals based, at least in part, on the values to which the timer is set. - Utilizing a roaming timer to put off a roaming attempt may be useful in many different operational scenarios. For example, if during a current association with an access point, a mobile station enjoys a “high quality” connection, periodic attempts to roam may not be the most efficient use of the mobile station's resources. On the other hand, if a mobile station has a lower quality connection, the interval between roaming attempts may be modified to make more efficient use of the mobile station's resources.
- In
block 230, a second metric is compared to a second threshold, and inblock 240, the timer is conditionally set to a second value. Various embodiments of the present invention are not limited to two metrics, two thresholds, and two timer values as shown inFIG. 2 . For example, in some embodiments, many more than two metrics are utilized. Further, in some embodiments, a single metric is used, and the single metric is compared against multiple thresholds. The result of the comparison with multiple thresholds may result in setting a roaming timer with one of many different possible timer values. - In
block 250, an attempt to roam is made when the timer expires. In some embodiments, the timer runs in the “background.” For example, in embodiments that include a hardware timer, the hardware may be adapted to decrement a counter every clock cycle or every N clock cycles. The counter may perform as a roaming timer when loaded with a timer value, and the counter is decremented in the background. In other embodiments that include a hardware timer, the counter is only decremented when enabled, and various method embodiments of the present invention not only set the timer, but also enable and disable the timer. When the timer times out, the roaming attempt may be initiated in one of many different ways. For example, the hardware timer may cause a processor interrupt, or may set a bit in a status register. The present invention is not limited in this respect. - In embodiments that include a software timer, the software timer may be implemented as a software counter that is decremented in the background. For example, a software routine may be scheduled to run every second, or every 100 milliseconds, and each time the software routine runs, it may decrement the counter that functions as the roaming timer. Further, the software counter may be enabled or disabled in support of the operation of the roaming timer. The interval between successive decrement operations of the counter is not a limitation of the present invention.
- In some embodiments,
method 200 may be performed periodically. For example,method 200 may run every second or every ten seconds in a mobile station, such as mobile station 102 (FIG. 1 ). As a result, roaming attempts may be put off indefinitely, or may be performed at intervals defined, at least in part, by the timer values. -
FIG. 3 shows a flowchart in accordance with various embodiments of the present invention. In some embodiments,method 300 may be used to decide when to attempt to roam in a wireless network. In some embodiments,method 300, or portions thereof, is performed by a wireless network interface, a processor, or an electronic system, embodiments of which are shown in the various figures.Method 300 is not limited by the particular type of apparatus, software element, or person performing the method. The various actions inmethod 300 may be performed in the order presented, or may be performed in a different order. Further, in some embodiments, some actions listed inFIG. 3 are omitted frommethod 300. -
Method 300 is shown beginning atblock 305 in which a first metric is compared to a threshold. The metric includes a determination of how many “beacons” have been missed. In some embodiments, a beacon is a packet or frame periodically transmitted by an access point. If many beacons have been missed by a mobile station, this may be indicative of a poor quality connection between the mobile station and the access point. As shown inFIG. 3 , if many beacons have been missed, an attempt to roam may be performed at 310. - The attempt to roam at 310 may be performed by resetting a roaming timer, or by performing an attempt to roam regardless of the state of the roaming timer. The number of missed beacons used as a threshold in
block 305 may be set to any threshold. In some embodiments, if more than 50% of beacons are missed, an attempt to roam is performed atblock 310. In other embodiments, if more than 60% of beacons are missed, an attempt to roam is performed atblock 310. The particular threshold used inblock 305 is not a limitation of the present invention. - At 315, a percentage of “retries” is checked, and if it is not high, then
method 200 ends with a determination to not attempt roaming atblock 320. A “retry” corresponds to a packet or frame that is retransmitted because of a previously unsuccessful attempt at transmission. The percentage of retries represents a metric that can be either gathered or calculated, and the number to which the percentage is compared represents a threshold. The actual percentage used as a threshold is not a limitation of the present invention. - The remaining decision blocks (325, 335, and 345) compare a metric against a threshold, and conditionally enter one of four states (330, 340, 350, or 360) depending on the outcome of the decisions. Although three decision blocks and four states are shown, any number of decision blocks and states may be implemented without departing from the scope of the present invention.
-
Decision block 325 compares a current data rate to a threshold. In some embodiments, the threshold is the lowest data rate available. For example, in some embodiments, the mobile station will reduce the data rate as the distance to the access point increases, or as the received signal strength decreases. If the current data rate corresponds to the lowest rate available, then if the signal degrades further, the mobile station may be forced to disassociate. If the current rate is low, thenmethod 300 enters STATE A (block 330) where the roaming timer is set to 10 seconds. -
Block 330 is referred to as a “state” in part because, if in subsequent invocations ofmethod 300, STATE A is re-entered, then the timer is not necessarily set to 10 seconds again. For example, assuming thatmethod 300 is performed once a second, and each time it is performedblock 330 is reached, thefirst time block 330 is reached, STATE A will be entered, and the roaming timer will be set to 10 seconds. Thesecond time block 330 is reached, the roaming timer will not be set, because STATE A has remained the active state. In this example,method 300 will be performed 10 times, block 330 will be reached each time, the roaming timer will expire, and an attempt to roam will be performed. - If, in
method 300,decision block 335 is reached, an average received signal strength indicator (RSSI) is compared against a threshold. Inblock 335, the RSSI is the metric, and the “current rate threshold” is the threshold to which the metric is compared. If the average RSSI is less than the current rate threshold, then block 340 is reached, and if the current state is not STATE B, STATE B is entered, and the roaming timer is set to two minutes. Ifblock 340 was reached the last time thatmethod 300 was performed, then the current state remains STATE B, and the timer is not necessarily set. Ifblock 340 is reached eachtime method 300 is performed over a two minute period, the timer will expire, and an attempt to roam will be performed. - An example of a “current rate threshold” is shown in
FIG. 4 at 410. As shown inFIG. 4 , the current rate threshold may vary as a function of the current rate. Four current rate threshold values are shown inFIG. 4 , each corresponding to a different rate. Any number of current rate thresholds may exist without departing from the scope of the present invention. In some embodiments, the thresholds are different as shown inFIG. 4 , and in other embodiments, the thresholds are the same. - Referring now back to
FIG. 3 , ifdecision block 345 is reached, an average received signal strength indicator (RSSI) is compared against a second threshold. Inblock 345, the RSSI is the metric, and the “good threshold” is the threshold to which the metric is compared. If the average RSSI is less than the good threshold, then block 350 is reached, and if the current state is not STATE C, STATE C is entered, and the roaming timer is set to four minutes. Ifblock 350 was reached the last time thatmethod 300 was performed, then the current state remains STATE C, and the timer is not necessarily set. Ifblock 350 is reached eachtime method 300 is performed over a four minute period, the timer will expire, and an attempt to roam will be performed. - If in
block 345, the average RSSI is not below the good threshold, then block 360 is reached, and if the current state is not STATE D, STATE D is entered, and the roaming timer is set to fifteen minutes. Ifblock 360 was reached the last time thatmethod 300 was performed, then the current state remains STATE D, and the timer is not necessarily set. Ifblock 360 is reached eachtime method 300 is performed over a fifteen minute period, the timer will expire, and an attempt to roam will be performed. - An example of a “good threshold” is shown in
FIG. 4 at 420. As shown inFIG. 4 , the good threshold does not vary as a function of the current rate, but this is not a limitation of the present invention. For example, in some embodiments the good threshold may vary as a function of current rate, similar to the current rate threshold shown at 410. - In some embodiments,
method 300 is performed periodically within a mobile station such as mobile station 102 (FIG. 1 ). For example,method 300 may be performed once a second, or once every ten seconds. In some embodiments, eachtime method 300 is performed, the roaming timer is either set to a value or decremented. In other embodiments, the roaming timer is decremented in the background, andmethod 300 either sets the roaming timer, or performs no operation on the roaming timer. -
Method 300 allows a mobile station to measure a “perceived quality” of a current connection. The perceived quality of the connection is based on various metrics as shown inmethod 300. In some embodiments, the roaming timer is set to a relatively high value when the perceived quality is high. Also in some embodiments, the roaming timer is set to a relatively low value when the perceived quality is lower. -
FIG. 4 shows a plot with various received signal strength indicator thresholds. The vertical axis corresponds to thresholds for comparison against the received signal strength indicator (RSSI). The horizontal axis represents data rates. As shown inFIG. 4 , the current rate threshold is a function of the current data rate, and the good threshold is constant. In some embodiments, more than two types of thresholds are utilized, and in some embodiments, more than one threshold is a function of data rate. -
FIG. 5 shows a system diagram in accordance with various embodiments of the present invention.Electronic system 500 includesantenna 510,radio interface 520, physical layer (PHY) 530, media access control layer (MAC) 540,processor 560, roamingtimer 550, andmemory 570.Electronic system 500 also includeshost processor 580 andhost memory 590. In operation,system 500 sends and receivessignals using antenna 510, and the signals are processed by the various elements shown inFIG. 5 .Antenna 510 may be a directional antenna or an omni-directional antenna. As used herein, the term omni-directional antenna refers to any antenna having a substantially uniform pattern in at least one plane. For example, in some embodiments,antenna 510 may be an omni-directional antenna such as a dipole antenna, or a quarter wave antenna. Also for example, in some embodiments,antenna 510 may be a directional antenna such as a parabolic dish antenna or a Yagi antenna. -
Host processor 580 is coupled toprocessor 560 bybus 565. The blocks shown to the left ofbus 565 may be an apparatus such as a wireless network interface, and the blocks shown to the right ofbus 565 may be an apparatus or system such as a laptop computer. The wireless interface may be on a card that plugs into the laptop computer, or may be a wireless interface that is integral with the computer. In some embodiment,bus 565 represents a communications bus such as a peripheral component interconnect (PCI) bus, however this is not a limitation of the present invention. -
Radio interface 520 may include circuitry to support the transmission and reception of radio frequency (RF) signals. For example, in some embodiments,radio interface 520 includes an RF receiver to receive signals and perform “front end” processing such as low noise amplification (LNA), filtering, frequency conversion or the like. Also for example, in some embodiments,radio interface 520 includes circuits to support frequency up-conversion, and an RF transmitter. The invention is not limited by the contents or function ofradio interface 520. - Physical layer (PHY) 530 may be any suitable physical layer implementation. For example,
PHY 530 may be a circuit block that implements a physical layer that complies with the IEEE 802.11 standard or other standard. Examples include, but are not limited to, direct sequence spread spectrum (DSSS), frequency hopping spread spectrum (FHSS), and orthogonal frequency division multiplexing (OFDM). Media access control layer (MAC) 540 may be any suitable media access control layer implementation. For example,MAC 540 may be implemented in software, or hardware or any combination thereof. In some embodiments,MAC 540 may be implemented in software that is partially executed byprocessor 560 and partially executed byhost processor 580. -
Roaming timer 550 may be a timer utilized to put off a decision to roam, such as roaming timer 104 (FIG. 1 ).Roaming timer 550 may be implemented in hardware or software or any combination. In some embodiments, roamingtimer 550 is set to various values, and when the timer expires, an attempt to roam is performed. For example, methods such as method 200 (FIG. 2 ) and method 300 (FIG. 3 ) may be used to compare metrics to thresholds and conditionally set roamingtimer 550. In some embodiments, roamingtimer 550 may be coupled to (or implemented by)processor 560. In other embodiments, roamingtimer 550 may be coupled to (or implemented by)host processor 580. -
Processor 560 may be a processor that sets roamingtimer 550 based, at least in part, on comparisons between metrics and thresholds. For example,processor 560 may perform methods such as method 200 (FIG. 2 ) or method 300 (FIG. 3 ).Processor 560 represents any type of processor, including but not limited to, a microprocessor, a digital signal processor, a microcontroller, or the like. In some embodiments,processor 560 does not exist, and dedicated digital logic or other hardware is coupled to roamingtimer 550. In these embodiments, the dedicated digital logic or other hardware may set roamingtimer 550 based, at least in part, on comparisons between metrics and thresholds. -
Memory 570 represents an article that includes a machine readable medium. For example,memory 570 represents a random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), read only memory (ROM), flash memory, or any other type of article that includes a medium readable byprocessor 560.Memory 570 can store instructions for performing the execution of the various method embodiments of the present invention. -
Host processor 580 may be any processor capable of communication withprocessor 560 overbus 565.Host processor 580 represents any type of processor, including but not limited to, a microprocessor, a personal computer, a workstation, or the like. In some embodiments,host processor 580 may set a roaming timer. For example,host processor 580 may implementMAC 540 or a portion ofMAC 540 in a software driver or other software. A MAC (or a portion thereof) implemented inprocessor 580 may include one or more roaming timers as discussed herein. -
Host memory 590 represents an article that includes a machine readable medium. For example,host memory 590 represents any one or more of the following: a hard disk, a floppy disk, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), read only memory (ROM), flash memory, CDROM, or any other type of article that includes a medium readable byhost processor 580. - Systems represented by the various foregoing figures can be of any type. Examples of represented systems include computers (e.g., desktops, laptops, handhelds, servers, tablets, web appliances, routers, etc.), wireless communications devices (e.g., cellular phones, cordless phones, pagers, personal digital assistants, etc.), computer-related peripherals (e.g., printers, scanners, monitors, etc.), entertainment devices (e.g., televisions, radios, stereos, tape and compact disc players, video cassette recorders, camcorders, digital cameras, MP3 (Motion Picture Experts Group, Audio Layer 3) players, video games, watches, etc.), and the like.
- Roaming timers, processors, wireless network interfaces, and other embodiments of the present invention can be implemented in many ways. In some embodiments, they are implemented in electronics as part of mobile stations for use in wireless networks. In some embodiments, design descriptions of the various embodiments of the present invention are included in libraries that enable designers to include them in custom or semi-custom designs. For example, any of the disclosed embodiments can be implemented in a synthesizable hardware design language, such as VHDL or Verilog, and distributed to designers for inclusion in standard cell designs, gate arrays, or the like. Likewise, any embodiment of the present invention can also be represented as a hard macro targeted to a specific manufacturing process.
- Although the present invention has been described in conjunction with certain embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art readily understand. Such modifications and variations are considered to be within the scope of the invention and the appended claims.
Claims (16)
1. A method to initiate roaming in a mobile station, wherein the mobile station is associated with a first access point, the method comprising:
communicating with the first access point to receive a request to end the association of the mobile station with the first access point and associate the mobile station with a second access point; and
associating the mobile station with the second access point responsive to the request.
2. The method of claim 1 , wherein the mobile station comprises a roaming timer, and wherein associating the mobile station with the second access point responsive to the request comprises:
resetting the roaming timer, wherein the roaming timer is to determine a delay time of associating the mobile station with the second access point responsive to the determination.
3. The method of claim 1 , further comprising:
determining a number of missed beacons from the first access point; and
comparing the number of missed beacons from the first access point with a corresponding threshold.
4. The method of claim 1 , further comprising:
determining a number of retransmissions of packets or frames to the first access point; and
comparing the number of retransmissions of packets or frames to the first access point with a corresponding threshold.
5. The method of claim 1 , further comprising:
determining that the second access point is better than the first access point.
6. The method of claim 1 , further comprising:
determining a data rate of transmissions of packets or frames to the first access point; and
comparing the data rate of transmissions of packets or frames to the first access point with a corresponding threshold.
7. The method of claim 1 , further comprising:
determining an average received signal strength indicator (RSSI) from received packets or frames from the first access point; and
comparing the RSSI with a corresponding threshold.
8. The method of claim 1 , wherein the mobile station and the access point are operable in accordance with Institute of Electrical and Electronics Engineers (IEEE) 802.11v and/or IEEE 802.11k.
9. A mobile station comprising:
an omni-directional antenna;
a radio interface coupled to the omni-directional antenna to interact with a first access point; and
a processor coupled to the radio interface, wherein the processor is to:
communicate with the first access point to receive a request to end the association of the mobile station with the first access point and associate the mobile station with a second access point; and
associate the mobile station with the second access point responsive to the request.
10. The mobile station of claim 9 , wherein the mobile station further comprises a roaming timer, and wherein the processor to associate the mobile station with the second access point responsive to the request is to:
reset the roaming timer, wherein the roaming timer is to determine a delay time of associating the mobile station with the second access point responsive to the determination.
11. The mobile station of claim 9 , wherein the processor is to further to:
determine a number of missed beacons from the first access point; and
compare the number of missed beacons from the first access point with a corresponding threshold.
12. The mobile station of claim 9 , wherein the processor is to further to:
determine a number of retransmissions of packets or frames to the first access point; and
compare the number of retransmissions of packets or frames to the first access point with a corresponding threshold.
13. The mobile station of claim 9 , wherein the processor is to further to:
determine that the second access point is better than the first access point.
14. The mobile station of claim 9 , wherein the processor is to further to:
determine a data rate of transmissions of packets or frames to the first access point; and
compare the data rate of transmissions of packets or frames to the first access point with a corresponding threshold.
15. The mobile station of claim 9 , wherein the processor is to further to:
determine an average received signal strength indicator (RSSI) from received packets or frames from the first access point; and
compare the RSSI with a corresponding threshold.
16. The mobile station of claim 9 , wherein the mobile station and the access point are to operate in accordance with Institute of Electrical and Electronics Engineers (IEEE) 802.11v and/or IEEE 802.11k.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/868,010 US20100316036A1 (en) | 2003-09-30 | 2010-08-25 | Wireless network roaming timer method and apparatus |
US13/159,785 US8190152B2 (en) | 2003-09-30 | 2011-06-14 | Wireless network roaming timer method and apparatus |
US13/461,660 US8457628B2 (en) | 2003-09-30 | 2012-05-01 | Wireless network roaming timer method and apparatus |
US13/785,265 US9094789B2 (en) | 2003-09-30 | 2013-03-05 | Mobile station with roaming timer |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/675,007 US7844266B2 (en) | 2003-09-30 | 2003-09-30 | Wireless network roaming timer method and apparatus |
US12/868,010 US20100316036A1 (en) | 2003-09-30 | 2010-08-25 | Wireless network roaming timer method and apparatus |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/675,007 Division US7844266B2 (en) | 2003-09-30 | 2003-09-30 | Wireless network roaming timer method and apparatus |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/159,785 Continuation US8190152B2 (en) | 2003-09-30 | 2011-06-14 | Wireless network roaming timer method and apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
US20100316036A1 true US20100316036A1 (en) | 2010-12-16 |
Family
ID=34377017
Family Applications (5)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/675,007 Active 2027-06-22 US7844266B2 (en) | 2003-09-30 | 2003-09-30 | Wireless network roaming timer method and apparatus |
US12/868,010 Abandoned US20100316036A1 (en) | 2003-09-30 | 2010-08-25 | Wireless network roaming timer method and apparatus |
US13/159,785 Expired - Lifetime US8190152B2 (en) | 2003-09-30 | 2011-06-14 | Wireless network roaming timer method and apparatus |
US13/461,660 Expired - Lifetime US8457628B2 (en) | 2003-09-30 | 2012-05-01 | Wireless network roaming timer method and apparatus |
US13/785,265 Expired - Fee Related US9094789B2 (en) | 2003-09-30 | 2013-03-05 | Mobile station with roaming timer |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/675,007 Active 2027-06-22 US7844266B2 (en) | 2003-09-30 | 2003-09-30 | Wireless network roaming timer method and apparatus |
Family Applications After (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/159,785 Expired - Lifetime US8190152B2 (en) | 2003-09-30 | 2011-06-14 | Wireless network roaming timer method and apparatus |
US13/461,660 Expired - Lifetime US8457628B2 (en) | 2003-09-30 | 2012-05-01 | Wireless network roaming timer method and apparatus |
US13/785,265 Expired - Fee Related US9094789B2 (en) | 2003-09-30 | 2013-03-05 | Mobile station with roaming timer |
Country Status (8)
Country | Link |
---|---|
US (5) | US7844266B2 (en) |
EP (1) | EP1678970B1 (en) |
CN (2) | CN1853429B (en) |
AT (1) | ATE406770T1 (en) |
DE (1) | DE602004016201D1 (en) |
HK (1) | HK1092631A1 (en) |
MY (1) | MY149278A (en) |
WO (1) | WO2005034548A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160044478A1 (en) * | 2013-06-07 | 2016-02-11 | Huawei Technologies Co., Ltd. | Service Processing Method, Terminal Device, and Service Roaming Network |
US20160226740A1 (en) * | 2013-09-27 | 2016-08-04 | Thomson Licensing | Method for testing a wireless link of a wi-fi node, and circuit performing the method |
US20160242078A1 (en) * | 2015-02-05 | 2016-08-18 | Telefonaktiebolaget Lm Ericsson (Publ) | Reporting intra-wlan mobility to 3gpp |
Families Citing this family (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040202122A1 (en) * | 2003-02-24 | 2004-10-14 | Floyd Backes | Wireless access point protocol program |
US7844266B2 (en) * | 2003-09-30 | 2010-11-30 | Intel Corporation | Wireless network roaming timer method and apparatus |
US8064903B2 (en) * | 2003-12-30 | 2011-11-22 | Cisco Technology, Inc. | Methods and apparatus for reducing roaming latency in a mobile node |
US7969937B2 (en) | 2004-03-23 | 2011-06-28 | Aruba Networks, Inc. | System and method for centralized station management |
US9432848B2 (en) | 2004-03-23 | 2016-08-30 | Aruba Networks, Inc. | Band steering for multi-band wireless clients |
US7515548B2 (en) * | 2004-09-28 | 2009-04-07 | Texas Instruments Incorporated | End-point based approach for determining network status in a wireless local area network |
KR100705578B1 (en) * | 2005-07-11 | 2007-04-10 | 삼성전자주식회사 | Wireless Distribution System Repeater apparatus and method in wireless LAN system |
WO2007040515A2 (en) * | 2005-09-30 | 2007-04-12 | Mitsubishi Electric Research Laboratories | Training signals for selecting antennas and beams in mimo wireless lans |
EP2239980B1 (en) * | 2006-03-29 | 2012-05-09 | Huawei Technologies Co., Ltd. | Reducing service interruption of a terminal during packet switched handover in a mobile communication |
US7706790B2 (en) * | 2006-04-04 | 2010-04-27 | Kyocera Corporation | System scanning method and arrangement for mobile wireless communication devices |
US20070254687A1 (en) * | 2006-05-01 | 2007-11-01 | Shary Nassimi | Wirefree Intercom Having Secure Transmission System and Process |
US7869823B2 (en) * | 2006-05-01 | 2011-01-11 | The Chamberlain Group, Inc. | Wirefree intercom having error free transmission system and process |
US20070254680A1 (en) * | 2006-05-01 | 2007-11-01 | Shary Nassimi | Wirefree intercom having low power system and process |
WO2008039124A1 (en) * | 2006-09-25 | 2008-04-03 | Telefonaktiebolaget Lm Ericsson (Publ) | A method, a serving cell controller and a system for detecting support for packet-switched handover |
US20080095130A1 (en) * | 2006-10-23 | 2008-04-24 | Ajay Puri | System and method of network identifier polling |
ATE535117T1 (en) * | 2006-10-23 | 2011-12-15 | Research In Motion Ltd | SYSTEM AND METHOD FOR INQUIRING A NETWORK IDENTIFICATION |
EP2079253A1 (en) * | 2008-01-09 | 2009-07-15 | Panasonic Corporation | Non-3GPP to 3GPP network handover optimizations |
JP5643991B2 (en) * | 2008-04-17 | 2014-12-24 | シンクロニー, インコーポレイテッドSynchrony, Inc. | High-speed permanent magnet motor and generator with low loss metal rotor |
US8330311B2 (en) | 2008-04-18 | 2012-12-11 | Dresser-Rand Company | Magnetic thrust bearing with integrated electronics |
US9583991B2 (en) * | 2009-06-24 | 2017-02-28 | Synchrony, Inc. | Systems, devices, and/or methods for managing magnetic bearings |
US8987959B2 (en) | 2010-06-23 | 2015-03-24 | Dresser-Rand Company | Split magnetic thrust bearing |
JP5695936B2 (en) * | 2011-02-25 | 2015-04-08 | 任天堂株式会社 | Information processing program, information processing apparatus, information processing system, and information processing method |
US8504021B1 (en) * | 2011-07-07 | 2013-08-06 | Sprint Communications Company L.P. | Performance scanning and correlation in wireless communication devices |
US9474017B2 (en) | 2012-05-31 | 2016-10-18 | Motorola Solutions, Inc. | Method and apparatus for controlling network selection |
US9176570B2 (en) | 2012-12-29 | 2015-11-03 | Intel Corporation | System and method for providing universal serial bus link power management policies in a processor environment |
US9198107B1 (en) | 2013-09-25 | 2015-11-24 | Sprint Spectrum L.P. | Managing network selection for wireless communication |
US9326230B2 (en) | 2013-10-08 | 2016-04-26 | Qualcomm Incorporated | Multidimensional algorithm for roaming |
US10021064B2 (en) * | 2015-05-14 | 2018-07-10 | Honeywell International Inc. | Apparatus and method for translating industrial process control and automation system events into mobile notifications |
CN105357480B (en) * | 2015-11-10 | 2018-08-28 | 杭州敦崇科技股份有限公司 | Public place wireless networking safety management system and its operation method |
EP3682674B1 (en) | 2017-09-16 | 2022-03-16 | ARRIS Enterprises LLC | Selective probe-response suppression |
WO2019068106A1 (en) | 2017-09-30 | 2019-04-04 | Arris Enterprises Llc | Access-point discovery of wireless-network topology |
US10772002B2 (en) * | 2018-03-13 | 2020-09-08 | Arris Enterprises Llc | Selective probe-response suppression based on SNR |
CN111278073B (en) * | 2020-01-20 | 2022-03-08 | 普联技术有限公司 | WIFI roaming setting method and device, wireless connection equipment and readable storage medium |
CN115372487B (en) * | 2021-05-18 | 2023-10-10 | 成都倍特得诺药业有限公司 | HPLC determination method for impurity E in granisetron hydrochloride |
Citations (27)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5152009A (en) * | 1989-08-08 | 1992-09-29 | Mitsubishi Denki Kabushiki Kaisha | Diversity reception control circuit |
US5432841A (en) * | 1992-07-10 | 1995-07-11 | Rimer; Neil A. | System for locating and communicating with mobile vehicles |
US5717688A (en) * | 1993-06-25 | 1998-02-10 | Netwave Technologies Limited | Wireless local area network with roaming indicating multiple communication ranges |
US5819178A (en) * | 1996-01-05 | 1998-10-06 | Northern Telecom Limited | Methods and apparatus for accessing subscriber information in interconnected wireless telecommunications networks |
US5995829A (en) * | 1997-07-03 | 1999-11-30 | Nokia Mobile Phones | Programmable system determination in dual-mode wireless communications systems |
US6052598A (en) * | 1997-09-30 | 2000-04-18 | At&T Corp | Method for predicting the location of a mobile station in a mobile communications network |
US6119001A (en) * | 1997-04-28 | 2000-09-12 | Telefonaktiebolaget Lm Ericsson (Publ) | Roamer service auto-activation and deactivation in a home location register |
US6192245B1 (en) * | 1995-07-01 | 2001-02-20 | Motorola, Inc. | Method for determining handover in a multicellular communications system |
US6233454B1 (en) * | 1996-10-18 | 2001-05-15 | Matsushita Electric Industrial Co., Ltd. | Mobile station |
US6233463B1 (en) * | 1996-09-04 | 2001-05-15 | Globalstar L.P. | Automatic satellite terrestrial mobile terminal roaming system and method |
US6330444B1 (en) * | 1998-11-16 | 2001-12-11 | Telefonaktiebolaget Lm Ericsson (Publ) | Pre-page timer |
US20020025810A1 (en) * | 2000-07-11 | 2002-02-28 | Takashi Takayama | High-speed roaming method of wireless LAN |
US20030069016A1 (en) * | 2001-10-09 | 2003-04-10 | Microsoft Corporation | System and method for providing agent-free and no-packet overhead mobility support with transparent session continuity for mobile devices |
US6580700B1 (en) * | 1995-10-27 | 2003-06-17 | Symbol Technologies, Inc. | Data rate algorithms for use in wireless local area networks |
US6668167B2 (en) * | 2000-01-26 | 2003-12-23 | Mcdowell Mark | Method and apparatus for sharing mobile user event information between wireless networks and fixed IP networks |
US20040039817A1 (en) * | 2002-08-26 | 2004-02-26 | Lee Mai Tranh | Enhanced algorithm for initial AP selection and roaming |
US20050070275A1 (en) * | 2003-09-30 | 2005-03-31 | Intel Corporation | Wireless network roaming timer method and apparatus |
US20050148328A1 (en) * | 2003-12-30 | 2005-07-07 | Cisco Technology, Inc., A Corporation Of California | Methods and apparatus for reducing roaming latency in a mobile node |
US7065063B2 (en) * | 2001-04-11 | 2006-06-20 | Research In Motion Limited | System and method for balancing communication traffic loading between adjacent base stations in a mobile communications network |
US20060187873A1 (en) * | 2005-02-18 | 2006-08-24 | Cisco Technology, Inc. | Pre-emptive roaming mechanism allowing for enhanced QoS in wireless network environments |
US7406319B2 (en) * | 2001-11-19 | 2008-07-29 | At&T Corp. | WLAN having load balancing by access point admission/termination |
US7440756B1 (en) * | 2004-05-21 | 2008-10-21 | Cisco Technology, Inc. | Controlling micro-roaming in a wireless LAN |
US20080286400A1 (en) * | 2007-05-15 | 2008-11-20 | Embarq Holdings Company, Llc | System and method for communicating with an optimal wireless communications carrier |
US7633915B1 (en) * | 2005-09-12 | 2009-12-15 | Sprint Spectrum L.P. | Use of positioning information to determine whether to trigger a packet-data-network re-registration when detecting multiple radio signals of sufficient strength |
US7706790B2 (en) * | 2006-04-04 | 2010-04-27 | Kyocera Corporation | System scanning method and arrangement for mobile wireless communication devices |
US20100110890A1 (en) * | 2008-11-05 | 2010-05-06 | At&T Mobility Ii Llc | Wireless network selection management |
US20100136969A1 (en) * | 2008-12-01 | 2010-06-03 | Telefonaktiebolaget L M Ericsson (Publ) | Neighbor Cell List Compilation Methods and Apparatus |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1183014A (en) | 1915-01-25 | 1916-05-16 | Berlin Machine Works | Tool-mounting. |
US5353331A (en) * | 1992-03-05 | 1994-10-04 | Bell Atlantic Network Services, Inc. | Personal communications service using wireline/wireless integration |
US5987062A (en) * | 1995-12-15 | 1999-11-16 | Netwave Technologies, Inc. | Seamless roaming for wireless local area networks |
US7350077B2 (en) * | 2002-11-26 | 2008-03-25 | Cisco Technology, Inc. | 802.11 using a compressed reassociation exchange to facilitate fast handoff |
US7263078B2 (en) * | 2002-12-18 | 2007-08-28 | Microsoft Corporation | Method and apparatus for scanning in wireless computing devices |
US7020438B2 (en) * | 2003-01-09 | 2006-03-28 | Nokia Corporation | Selection of access point in a wireless communication system |
US7873358B2 (en) * | 2003-08-05 | 2011-01-18 | John Yue Jun Jiang | Method and system for providing inbound traffic redirection solution |
US7573857B1 (en) * | 2004-01-16 | 2009-08-11 | Qualcomm Incorporated | Capacity management for wireless local area networks |
US8406757B1 (en) * | 2011-03-29 | 2013-03-26 | Sprint Communications Company L.P. | Wireless device network rescan rate determination based on wireless coverage availability |
-
2003
- 2003-09-30 US US10/675,007 patent/US7844266B2/en active Active
-
2004
- 2004-08-25 MY MYPI20043464A patent/MY149278A/en unknown
- 2004-09-29 AT AT04789462T patent/ATE406770T1/en not_active IP Right Cessation
- 2004-09-29 CN CN2004800271332A patent/CN1853429B/en active Active
- 2004-09-29 CN CN2010101586021A patent/CN101895859A/en active Pending
- 2004-09-29 DE DE602004016201T patent/DE602004016201D1/en active Active
- 2004-09-29 WO PCT/US2004/032441 patent/WO2005034548A1/en active Application Filing
- 2004-09-29 EP EP04789462A patent/EP1678970B1/en active Active
-
2006
- 2006-08-14 HK HK06109017.4A patent/HK1092631A1/en not_active IP Right Cessation
-
2010
- 2010-08-25 US US12/868,010 patent/US20100316036A1/en not_active Abandoned
-
2011
- 2011-06-14 US US13/159,785 patent/US8190152B2/en not_active Expired - Lifetime
-
2012
- 2012-05-01 US US13/461,660 patent/US8457628B2/en not_active Expired - Lifetime
-
2013
- 2013-03-05 US US13/785,265 patent/US9094789B2/en not_active Expired - Fee Related
Patent Citations (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5152009A (en) * | 1989-08-08 | 1992-09-29 | Mitsubishi Denki Kabushiki Kaisha | Diversity reception control circuit |
US5432841A (en) * | 1992-07-10 | 1995-07-11 | Rimer; Neil A. | System for locating and communicating with mobile vehicles |
US5717688A (en) * | 1993-06-25 | 1998-02-10 | Netwave Technologies Limited | Wireless local area network with roaming indicating multiple communication ranges |
US6192245B1 (en) * | 1995-07-01 | 2001-02-20 | Motorola, Inc. | Method for determining handover in a multicellular communications system |
US6580700B1 (en) * | 1995-10-27 | 2003-06-17 | Symbol Technologies, Inc. | Data rate algorithms for use in wireless local area networks |
US5819178A (en) * | 1996-01-05 | 1998-10-06 | Northern Telecom Limited | Methods and apparatus for accessing subscriber information in interconnected wireless telecommunications networks |
US6233463B1 (en) * | 1996-09-04 | 2001-05-15 | Globalstar L.P. | Automatic satellite terrestrial mobile terminal roaming system and method |
US6233454B1 (en) * | 1996-10-18 | 2001-05-15 | Matsushita Electric Industrial Co., Ltd. | Mobile station |
US6119001A (en) * | 1997-04-28 | 2000-09-12 | Telefonaktiebolaget Lm Ericsson (Publ) | Roamer service auto-activation and deactivation in a home location register |
US5995829A (en) * | 1997-07-03 | 1999-11-30 | Nokia Mobile Phones | Programmable system determination in dual-mode wireless communications systems |
US6052598A (en) * | 1997-09-30 | 2000-04-18 | At&T Corp | Method for predicting the location of a mobile station in a mobile communications network |
US6330444B1 (en) * | 1998-11-16 | 2001-12-11 | Telefonaktiebolaget Lm Ericsson (Publ) | Pre-page timer |
US6668167B2 (en) * | 2000-01-26 | 2003-12-23 | Mcdowell Mark | Method and apparatus for sharing mobile user event information between wireless networks and fixed IP networks |
US20020025810A1 (en) * | 2000-07-11 | 2002-02-28 | Takashi Takayama | High-speed roaming method of wireless LAN |
US7065063B2 (en) * | 2001-04-11 | 2006-06-20 | Research In Motion Limited | System and method for balancing communication traffic loading between adjacent base stations in a mobile communications network |
US20030069016A1 (en) * | 2001-10-09 | 2003-04-10 | Microsoft Corporation | System and method for providing agent-free and no-packet overhead mobility support with transparent session continuity for mobile devices |
US7406319B2 (en) * | 2001-11-19 | 2008-07-29 | At&T Corp. | WLAN having load balancing by access point admission/termination |
US20040039817A1 (en) * | 2002-08-26 | 2004-02-26 | Lee Mai Tranh | Enhanced algorithm for initial AP selection and roaming |
US7844266B2 (en) * | 2003-09-30 | 2010-11-30 | Intel Corporation | Wireless network roaming timer method and apparatus |
US20050070275A1 (en) * | 2003-09-30 | 2005-03-31 | Intel Corporation | Wireless network roaming timer method and apparatus |
US20050148328A1 (en) * | 2003-12-30 | 2005-07-07 | Cisco Technology, Inc., A Corporation Of California | Methods and apparatus for reducing roaming latency in a mobile node |
US7440756B1 (en) * | 2004-05-21 | 2008-10-21 | Cisco Technology, Inc. | Controlling micro-roaming in a wireless LAN |
US20060187873A1 (en) * | 2005-02-18 | 2006-08-24 | Cisco Technology, Inc. | Pre-emptive roaming mechanism allowing for enhanced QoS in wireless network environments |
US7633915B1 (en) * | 2005-09-12 | 2009-12-15 | Sprint Spectrum L.P. | Use of positioning information to determine whether to trigger a packet-data-network re-registration when detecting multiple radio signals of sufficient strength |
US7706790B2 (en) * | 2006-04-04 | 2010-04-27 | Kyocera Corporation | System scanning method and arrangement for mobile wireless communication devices |
US20080286400A1 (en) * | 2007-05-15 | 2008-11-20 | Embarq Holdings Company, Llc | System and method for communicating with an optimal wireless communications carrier |
US20100110890A1 (en) * | 2008-11-05 | 2010-05-06 | At&T Mobility Ii Llc | Wireless network selection management |
US20100136969A1 (en) * | 2008-12-01 | 2010-06-03 | Telefonaktiebolaget L M Ericsson (Publ) | Neighbor Cell List Compilation Methods and Apparatus |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160044478A1 (en) * | 2013-06-07 | 2016-02-11 | Huawei Technologies Co., Ltd. | Service Processing Method, Terminal Device, and Service Roaming Network |
US10123185B2 (en) * | 2013-06-07 | 2018-11-06 | Huawei Technologies Co., Ltd. | Service processing method, terminal device, and service roaming network |
US10368210B2 (en) * | 2013-06-07 | 2019-07-30 | Huawei Technologies Co., Ltd. | Service processing method, terminal device, and service roaming network |
US20160226740A1 (en) * | 2013-09-27 | 2016-08-04 | Thomson Licensing | Method for testing a wireless link of a wi-fi node, and circuit performing the method |
US10862789B2 (en) * | 2013-09-27 | 2020-12-08 | Airties Belgium Sprl | Method for testing a wireless link of a Wi-Fi node, and circuit performing the method |
US11641318B2 (en) | 2013-09-27 | 2023-05-02 | Airties Belgium Sprl | Method for testing a wireless link of a Wi-Fi node, and circuit performing the method |
US20160242078A1 (en) * | 2015-02-05 | 2016-08-18 | Telefonaktiebolaget Lm Ericsson (Publ) | Reporting intra-wlan mobility to 3gpp |
US10341905B2 (en) * | 2015-02-05 | 2019-07-02 | Telefonaktiebolaget Lm Ericsson (Publ) | Reporting intra-WLAN mobility to 3GPP |
Also Published As
Publication number | Publication date |
---|---|
HK1092631A1 (en) | 2007-02-09 |
ATE406770T1 (en) | 2008-09-15 |
US8190152B2 (en) | 2012-05-29 |
US20110244856A1 (en) | 2011-10-06 |
MY149278A (en) | 2013-08-15 |
EP1678970B1 (en) | 2008-08-27 |
CN1853429B (en) | 2010-05-12 |
WO2005034548A1 (en) | 2005-04-14 |
US20130176882A1 (en) | 2013-07-11 |
EP1678970A1 (en) | 2006-07-12 |
US9094789B2 (en) | 2015-07-28 |
US20050070275A1 (en) | 2005-03-31 |
CN101895859A (en) | 2010-11-24 |
CN1853429A (en) | 2006-10-25 |
US7844266B2 (en) | 2010-11-30 |
US20120214482A1 (en) | 2012-08-23 |
DE602004016201D1 (en) | 2008-10-09 |
US8457628B2 (en) | 2013-06-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8190152B2 (en) | Wireless network roaming timer method and apparatus | |
US7363379B2 (en) | Access point association history in wireless networks | |
US8346272B2 (en) | Adaptive sensitivity in wireless communication | |
US7830848B2 (en) | Network-wide clear channel assessment threshold | |
US7813295B2 (en) | Co-location interference avoidance in multiple protocol communication networks | |
US7542723B2 (en) | Direct link establishment in wireless networks | |
US20050245269A1 (en) | Channel scanning in wireless networks | |
US7415262B2 (en) | Wireless access point power control | |
US20130039351A1 (en) | Multiple mode support in a wireless local area network | |
US20060277450A1 (en) | Adaptive radio resource management for wireless local area networks | |
US20010022806A1 (en) | Base station apparatus for radiocommunication network, method of controlling communication across radiocommunication network, radiocommunication network system, and radio terminal apparatus | |
US7574176B2 (en) | Channel selection in a wireless network | |
WO2005064869A1 (en) | Preemptive dynamic frequency selection | |
CN101904214A (en) | Method and apparatus for resolving blinded-node problems in wireless networks | |
CN114365579B (en) | Apparatus, system, and method for mitigating aggressive medium reservation | |
US20040252641A1 (en) | Classifier for IEEE 802.11g receiver | |
US20220338063A1 (en) | Method of dynamic transceiver configuration | |
US11864112B2 (en) | Apparatus, method and computer program | |
CN115669173A (en) | Method, apparatus and computer program product for wireless communication | |
CN117896795A (en) | Assisted roaming | |
JP2005260813A (en) | Radio communication system, radio communication apparatus and method, recording medium, and program |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |