KR20060097023A - Apparatus and method for storing and accessing media sensing time histogram measurement results in a management information basetable - Google Patents

Abstract

A Medium Sensing Time Histogram Table structure provides for including a Management Information Base (MIB) that stores and accesses media sensing time histogram measurement results, such as media sensing time histogram measurement reports. To this end, a predetermined number of entries may be provided in the media sensing time histogram report table. Apparatus and methods are provided by a wireless device for inputting and accessing entries in a media sensing time histogram report table. This method and apparatus are used in IEEE 802.11k as well as WLAN, which requires measurement of the medium.

Description

Apparatus and method for storing and accessing media sensing time histogram measurement results in a management information base table {APPARATUS AND METHOD FOR MANAGEMENT INFORMATION BASE TABLE FOR STORING AND ACCESSING MEDIUM SENSING TIME HISTOGRAM MEASUREMENT RESULTS}

The present invention relates to a wireless local area network (WLAN). More specifically, the present invention relates to wireless device management of a WLAN by accessing radio resources using Medium Sensing Time Histogram Reports. In particular, the present invention relates to an apparatus and method for using a management information base (MIB) table of a wireless device to store received history and locally generated media sensing time histogram reports. The method and apparatus of the present invention will be used in the IEEE 802.11k standard as well as in WLANs that require measurement of the medium.

The current wireless environment in which WLANs typically operate is mostly an unregulated rare resource. Wireless devices, such as WLAN stations (STAs), must be able to measure and access the wireless environment to take corresponding actions. A wireless device, such as a station (STA), may sense the medium and may also request another wireless device to report on its sensing or measurement of the medium. One form of measurement that may be requested is a media sensing time histogram. The format of the measurement request field 100 corresponding to the medium sensing time histogram request is shown in FIG. The field is described as follows.

a. The channel number 101 indicates a channel number to which a measurement request is applied.

b. Channel band 102 represents a frequency band obtained from Table 1 to which a channel number is applied.

Table 1-Channel Band 102 Specification for Wireless Measurement Requests

c. The measurement duration 103 may be set equal to the duration of the requested measurement represented by the timer device TU.

d. The subtype 104 of the media sensing measurement indicates the subtype from which the media sensing measurement is made. The available subtypes of media sensing measurements are defined in Table 2.

Table 2-Media Sensing Measurement Subform (104) Regulations

e. RPI threshold 105 represents the received power level threshold according to Table 4, as seen at the antenna connector. While collecting information about the RPI time histogram, the RPI threshold is used to determine if a media sensing event occurs.

f. Bin Offset 106 indicates the position of the first bin and is expressed in microseconds.

g. The bin interval 107 represents the time interval during which the media sensing event is counted in that bin and is represented by slot time. Media sensing events are defined in Table 3.

h. The bin number 108 represents the total number of time intervals covered by the time histogram.

The wireless device, such as the STA, reports the measurement using the measurement report element. The format of the measurement report field 200 of the media monitoring time histogram report is shown in FIG. The subfields are defined as follows.

a. Channel number 201 indicates a channel number to which the media sensing time histogram report is applied.

b. Channel band 202 represents the measured frequency band, which is obtained from Table 2 to which the channel number applies.

c. The measurement duration 203 is set equal to the duration during which the media sensing time histogram report is measured, which is expressed in TUs.

d. The medium sensing measurement subtype 204 represents a subtype of medium sensing time histogram report, as defined in Table 3.

Table 3-Media Sensing Measurement Subtype Regulations

e. RPI threshold 205 represents the received power level threshold according to Table 4, as seen at the antenna connector. The RPI threshold is used to determine if a media sensing event occurs while collecting information about the RPI time histogram.

Table 4-RPI Threshold Specification for RPI Time Histogram

The media sensing time histogram report includes the density at each of the N time intervals in each of the N bins, as measured in the characteristic channel for the duration of the measurement.

f. The bin offset 206 represents the position of the first bin, which is expressed in microseconds.

g. The bin interval 207 represents the time interval during which media sensing events are counted in this bin, which is expressed in slot time. Media sensing events are defined in Table 5.

h. The number of bins 208 represents the total number of time intervals covered by the time histogram.

i. The total number of media sensing events 209 indicates how many events were counted at the time of measurement.

Table 5-Specification of Media Sense Events

j. The bin i density 21i, (0≤i <N, e.g. 210, 211, 212, 213, ...) monitors the continuous monitoring state, and the STA is incremented in the count of B _i corresponding to the bin i. If a media mediation event occurs during the measurement at time t,

Therefore, the number of events is increased by one for each bin i. In the media sensing measurement, a histogram is generated that represents the probability distribution of media sensing events.

The ability to predict future wireless environment characteristics is based on past characteristics, which include a history of reports generated locally by the wireless device and also received by the device. At present, there is no way to generate a history of media sensing time histogram reports.

The IEEE802.11 standard specifies a request and reporting means comprising the format of FIGS. 1 and 2, but any mechanism for maintaining a history of such measurement over time by either a measuring STA or a STA receiving one or more measurement reports. Not available at this time. However, an attempt is made to store these reports in its MIB table by the STA as IEEE 802.1k. Thus, the present invention provides a mechanism for storing these reports and measurements obtained locally by the STA in a MIB table that can be implemented within the processing logic present under the control of the SME.

Accordingly, there is a need for a method of acquiring and maintaining a history of media sensing histogram measurement reports obtained over time.

The present invention is directed to an apparatus and method for causing a wireless device to obtain a history of media sensing time histogram reports. The present invention defines a format for storing locally generated and received media sensing time histogram reports in chronological order, such as input order, in the STA's MIB table.

Another aspect of the present invention is to obtain locally generated media sensing results and received media sensing time histogram reports, and to store them as at least one input to a MIB table of a wireless device whose MIB table format has been changed in accordance with the present invention. Provide the device. The device includes a transceiver coupled to a measurement management module that receives a locally generated media sensing report and a histogram report generated by another device and locally stores them as at least one input to a modified MIB table of the wireless device. do.

Other features and advantages of the present invention will become apparent from the following more detailed description of the following preferred embodiments, as shown in the accompanying drawings, wherein like reference characters refer to like parts throughout.

1 is a diagram illustrating a medium sensing time histogram request format;

2 is a diagram illustrating a format of a media sensing time histogram report according to an embodiment of the present invention;

3 is a simplified block diagram showing the structure of a wireless communication system to which an embodiment of the present invention is applied;

4 is a schematic block diagram of a wireless device of the communication system of FIG. 3, performing at least one of locally obtaining and requesting a media sensing time histogram report from another network device in accordance with an embodiment of the present invention; , Drawings changed to store it locally,

5 illustrates a format of a MIB table entry for a media sensing time histogram report table according to an embodiment of the present invention;

6 receives a request for a media sensing time histogram report, detects the media and generates a media sensing time histogram report, stores it as an entry in the media sensing histogram report table of the MIB, and finally sends it to the media. A flow chart representing the operational steps,

Figure 7 requests and receives a media sensing time histogram report for media, detects the media locally to generate a local media sensing time histogram report, and generates and receives the generated entries in the media sensing time histogram report table of the MIB table. A flow chart showing an operation step of storing as a.

Those skilled in the art will understand that the following description is provided for the purpose of illustration and not of limitation. The skilled person understands that various changes are made within the spirit of the invention and the scope of the appended claims. In order to make the present invention clear, unnecessary details of well-known functions and operations may be omitted from the present description.

3 shows an exemplary network environment to which an embodiment of the present invention is applied. As shown in FIG. 3, the wireless device 301 communicates with a plurality of wireless devices 301 via a wireless link, and the wireless devices communicate with each other via a plurality of wireless channels. A principal principle of the present invention is one form of a table that may be stored in a MIB table, which is different from the sequence of at least one medium sensing time histogram report as at least one entry in the medium sensing time histogram report table defined by the present invention. It is to provide a mechanism (i.e., MIB table) for storing at least one sequence received from the device and sensed locally.

Referring to FIG. 4, the wireless device 301 in the WLAN of FIG. 3 may include a system having the structure shown in the block diagram of FIG. 4. Each wireless device 301 includes a receiver 401, a processor 402, a time histogram management module 405, a memory 403 with a MIB table 404, a timer 406, and a transmitter 407. can do. The example system 400 of FIG. 4 is for illustrative purposes only. Although the present description refers to terms generally used to describe particular wireless devices, the present description and concepts are equally applicable to other processing systems, including systems having structures that are not similar to those shown in FIG. have.

In operation, receiver 401 and transmitter 407 are coupled to an antenna (not shown) to receive and send time histogram reports, requests for them, and also sense media for local generation of time histogram reports. . The processor 402 controls the time histogram management module 405 in storing and retrieving each medium sensing time histogram report entry in the medium sensing time histogram report table of the MIB table 404 stored in the memory 404. The time histogram management module is also used to maintain media sensing time histogram reports as a first-in, first-out data table to preserve the acceptance of entries. Further, in the preferred embodiment, the media sensing time histogram report entry that was received by the station management entity (SME) of the wireless device is maintained at a predetermined minimum value in the media sensing time histogram report table. In an implementation that meets the IEEE 802.11k standard, this minimum retention time is the dot 11 measurement report aging time after being recorded in the MIB. After this predetermined amount of time, since the report is recorded, the report entry can freely delete the memory by the SME. In addition to setting the storage time of entries in the MIB table, the timer 406 is used to determine when entries are updated.

5 illustrates a media sensing time histogram report entry in a media sensing time histogram table included in a MIB table according to the present invention. A software implementation of the media sensing time histogram report table according to the invention is included in Appendix I. Each entry in the medium sensing time histogram report table according to the present invention includes all fields of the medium sensing time histogram report shown in FIG. 2, and additional fields Index 501, RqtsToken 502, Iflndex 503, and STAAddr. (504), the empty Densities 210-21 (N-1) have an I = 0,... , Is stored in the empty table 505 indexed by the bean i Index 506i for N-1. The predetermined number of media sensing time histogram reports may be stored in the MIB table. This predetermined number is ten.

The wireless device, eg, the STA, reports the measurement using the measurement report element. The format of the measurement report field of each medium sensing time histogram report entry is shown in FIG. 5. Subfields are defined as follows.

a. Each entry in the table is indexed by Index.

b. The Request Token maintains the request token specified in the measurement request that requested the measurement report corresponding to this entry, and also exactly matches the original request token attribute.

c. The Interface Index is the interface index on which the report corresponding to this entry was received.

d. The STA Address is the MAC address of the measurement STA that makes up the measurement reported in the report corresponding to this entry.

e. Channel Number represents a channel number to which the media sensing time histogram report is applied.

f. Channel Band represents the measured frequency band, taken from Table 2 to which the Channel Number applies.

g. The Measurement Duration is expressed in TUs and will be set equal to the duration for which the media sensing time histogram report is measured.

h. The medium sensing measurement subtype represents a subtype of medium sensing time histogram report as defined in Table 6.

Table 6-Media Sensing Measurement Subtype Specification

i. The RPI threshold represents the received power level threshold according to Table 7, as can be seen at the antenna connector. While collecting information about the RPI time histogram, the RPI threshold is used to determine if a media sensing event occurs.

Table 7-RPI Threshold Definitions for the RPI Time Histogram

j. The media sensing time histogram report includes the density at each of the N intervals as measured in a particular channel for the duration of the measurement.

k. The total number of media sensing events 209 indicates how many events were counted at the time of measurement. Media sensing events are defined in Table 8.

l. An empty table stores the indexed bin i density by storing N pairs containing the bin i index and the associated bin i density. To calculate bin i density, 0 ≦ i <N, the measuring STA monitors the count increment of Bi corresponding to bin i and the continuous duration of the monitored state.

If a media sensing event occurs during the measurement at the furnace time t, the number of events per bin is increased by one. In medium sensing measurements, a histogram is generated to represent a probability distribution of medium sensing events in a timely manner.

Table 8-Specification of Media Sense Events

Figure 6 receives a media sensing time histogram measurement request (601), detects the media to generate a local media sensing time histogram report (602), and removes the old entries in the MIB (if necessary) while the media sensing time histogram report entries A flow diagram 600 of the operational steps performed by the wireless device 301 as storing the report as a FIFO in the local MIB (603), and sending the report to the address of the device contained therein (604). Indicates.

7 requests a media sensing time histogram measurement report (701), detects the media and generates a local media sensing time histogram report with the address of the local device contained therein (702), and reports the measurement contained therein. The wireless device 301 receives 703 via the medium to the address of the device, removing the old entry in the MIB (if necessary) and storing the report as a FIFO in the local MIB as a media sensing time histogram report entry (704). A flow chart 700 of operational steps performed by &lt; RTI ID = 0.0 &gt;

While the preferred embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the invention. In addition, various changes may be made to suit a particular situation and the spirit of the invention without departing from the scope of the invention. Accordingly, the invention is not to be limited to the specific embodiments disclosed as best contemplated for carrying out the invention, but includes all embodiments falling within the scope of the appended claims.

Claims (22)

A method of storing and accessing at least one medium sensing time histogram measurement report 200 by a plurality of wireless network devices 301, the method comprising: In the plurality of devices, Providing a table 404 having at least one entry 500 for storing and accessing at least one medium sensing time histogram measurement report 200; Obtaining at least one medium sensing time histogram measurement report 200; Storing the obtained at least one medium sensing time histogram measurement report as the at least one entry 500 in the prepared table 404; Identifying a source 504 of medium sensing time histogram measurements How to store and access the media sensing time histogram measurement report. The method of claim 1, The obtaining step, Receiving a media sensing time histogram measurement report from another of the plurality of devices (703); Generating at least one of steps 602 and 702 by the device to generate the media sensing time histogram measurement report. How to store and access the media sensing time histogram measurement report. The method of claim 2, The receiving step further includes the step of initially requesting (701) the media sensing time histogram measurement report from another of the plurality of devices. How to store and access the media sensing time histogram measurement report. The method of claim 2, The generating step, Including, in the medium sensing time histogram measurement report 200, at least one bin 210 comprising a count of occurrences of a media event of a predetermined type, each corresponding to a predetermined time interval; Initially detecting the medium at least one predetermined time interval; Counting the number of occurrences of at least one predetermined media sensing event 104 during the sensing step; Inputting the count into at least one bin 210 of medium sensing time histogram measurements corresponding to the predetermined form and a predetermined time interval; How to store and access the media sensing time histogram measurement report. The method of claim 4, wherein The sensing step further includes performing the sensing step on the predetermined frequency channel band 102 of the predetermined frequency channel 101 for the predetermined form. How to store and access the media sensing time histogram measurement report. The method of claim 5, wherein The storing step further includes removing the at least one entry 500 in accordance with a predetermined time dependent rule. How to store and access the media sensing time histogram measurement report. The method of claim 6, The storing step further includes storing (603, 704) the at least one measurement value in the prepared table 404 in a first-in first-out order. How to store and access the media sensing time histogram measurement report. The method of claim 7, wherein The prepared table 404 is a media sensing time histogram report table included in a management information base table located in each of the plurality of wireless network devices 301, Each of the plurality of devices is an IEEE 802.11 wireless network device. How to store and access the media sensing time histogram measurement report. The method of claim 8, Each of the at least one bin 210 further includes a bin index 506 of the location of the bin 210 in the order of the bins. How to store and access the media sensing time histogram measurement report. The method of claim 1, The storing step further includes removing the at least one entry according to a predetermined time dependent rule. How to store and access the media sensing time histogram measurement report. The method of claim 10, The storing step further includes storing (603, 704) the at least one measurement value in the prepared table in a first-in first-out order. How to store and access the media sensing time histogram measurement report. The method of claim 1, The prepared table is a media sensing time histogram report table included in a management information base table located in each of the plurality of wireless network devices 301, Each of the plurality of devices 301 is an IEEE 802.11 wireless network device How to store and access the media sensing time histogram measurement report. An apparatus 400 for storing and accessing a media sensing time histogram report by a wireless network device 301, A receiver 401 receiving at least one of a medium sensing input and a medium sensing time histogram measurement report 200, A transmitter 407 for transmitting a medium sensing time histogram measurement request 100, A memory 403 including a table 404 with at least one entry for storage of at least one medium sensing time histogram report 200; A processor 402 coupled to the receiving 401 to generate at least one medium sensing time histogram report entry 500 from at least one medium sensing input and the received medium sensing time histogram measurement report 200; Coupled to the processor 402 to receive and forward a media sensing time histogram report entry 500, store as the at least one entry, and access as the at least one entry in a table 404 of memory 403. A time histogram management module 405 for managing each Device that stores and accesses media sense time histogram reports. The method of claim 13, Further comprises a timer 406 coupled to the processor 402, which causes the processor 402 to direct the time histogram management module 405 to remove the at least one entry according to a predetermined time dependent rule. , The time histogram management module 405 is further configured to remove the at least one entry under control of the processor 402. Device that stores and accesses media sense time histogram reports. The method of claim 14, The time histogram management module 405 is further configured to store (603, 704) the at least one entry in the table 404 of the memory 403 in a first in, first out order of storing and accessing a media sense time histogram report. Device. The method of claim 15, The table 404 is a media sensing time histogram report table included in a management information base table. The wireless network device is an IEEE 802.11 wireless network device Device that stores and accesses media sense time histogram reports. The method of claim 13, The receiver 401 is further configured to receive a request 100 for a medium sensing time histogram measurement report 200, The transmitter 407 is also configured to transmit the medium sensing time histogram measurement report 200 in response to the received medium sensing time histogram measurement request 100. Device that stores and accesses media sense time histogram reports. The method of claim 17, The time histogram management module 405 is also configured to remove the at least one entry according to a predetermined rule. Device that stores and accesses media sense time histogram reports. The method of claim 18, The time histogram management module is further configured to store (603, 704) the at least one entry in the table 404 of the memory 403 in a first in, first out order. Device that stores and accesses media sense time histogram reports. The method of claim 19, The at least one entry 500 includes a count of occurrences of a media event of a predetermined type and further comprises an empty table 505 having at least one bin 210 corresponding to a predetermined time interval. Device that stores and accesses media sense time histogram reports. The method of claim 20, The at least one bin 210 further comprises a bin index 506 of the position of the bin 210 in the order of the bins. Device that stores and accesses media sense time histogram reports. The method of claim 21, The table is a media sensing time histogram report table included in the management information base table. The wireless network device is an IEEE 802.11 wireless network device Device that stores and accesses media sense time histogram reports.

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