Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B17/00—Monitoring; Testing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L43/00—Arrangements for monitoring or testing data switching networks
  • H04L43/06—Generation of reports
  • H04L43/065—Generation of reports related to network devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W24/00—Supervisory, monitoring or testing arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/02—Standardisation; Integration
  • H04L41/0213—Standardised network management protocols, e.g. simple network management protocol [SNMP]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W24/00—Supervisory, monitoring or testing arrangements
  • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/02—Terminal devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/18—Service support devices; Network management devices

Definitions

• the present invention relates to wireless local area networks (WLANs). More particularly the present invention relates to wireless device management of WLANS by assessing radio resources using Medium Sensing Time Histogram Reports. Most particularly, the present invention relates to an apparatus and method for using Management Information Base (MEB) Tables of a radio device to store a history of received and locally generated Medium Sensing Time Histogram Reports.
• MEB Management Information Base
• the method and apparatus of the present invention is intended for use in the IEEE 802.11k standard as well as any WLAN requiring measurement of the medium.
• Today's radio environment in which WLANs typically operate is a largely unregulated scarce resource.
• a radio device such as a WLAN station (STA) must be able to measure and assess the radio environment and take corresponding actions.
• a radio device such as a wireless station (STA) can both sense the medium and request other radio devices (other STAs) to report on their own sensing or measurement of the medium.
• STA wireless station
• Other STAs radio devices
• One type of measurement that can be requested is a Medium Sensing Time Histogram.
• a format of a Measurement Request field 100 corresponding to a Medium Sensing Time Histogram Request is shown in FIG. 1. The fields are described as follows: a.
• the Channel Number 101 indicates the channel number for which the measurement request applies.
• the Channel Band 1012 indicates the frequency band, taken from Table 1 in which the Channel Number applies.
• the Measurement Duration 103 can be set equal to the duration of the requested measurement, expressed in timer units (TUs).
• the Medium Sensing Measurement Subtype 104 indicates the subtype of Medium Sensing Measurements to make. The available subtypes of Medium Sensing Measurement are defined in Table 2.
• the RPI Threshold 105 identifies a received power level threshold according to Table 4, as seen at the antenna connector. The RPI Threshold is used to determine if a Medium Sensing Event occurs, while collecting information for the RPI Time Histogram.
• the Bin Offset 106 indicates the position of the first bin, expressed in microseconds.
• the Bin Interval 107 indicates the time interval during which Medium Sensing Events are counted to be in this bin, expressed in slot times. Medium Sensing Events are defined in Table 3.
• the Number of Bins 108 indicates the total number of time intervals that are covered by the time histogram.
• a radio device e.g., a STA, reports measurements using a Measurement Report element.
• the format of a Measurement Report field 200 of a Medium Sensing Time Histogram Report is shown in FIG. 2.
• the subfields are defined as follows: a.
• the Channel Number 201 indicates the channel number to which the Medium Sensing Time Histogram Report applies.
• the Channel Band 202 indicates the measured frequency band, taken from Table 2, in which the Channel Number applies.
• the Measurement Duration 203 is set equal to the duration over which the Medium Sensing Time Histogram Report was measured, expressed in TUs.
• the Medium Sensing Measurement Subtype 204 indicates the subtype of Medium Sensing Time Histogram Report, as defined in Table 3.
• the RPI Threshold 205 identifies a received power level threshold according to Table 4, as seen at the antenna connector.
• the RPI Threshold is used to determine if a Medium Sensing Event occurs, while collecting information for the RPI Time Histogram.
• the Medium Sensing Time Histogram Report contains in each of N Bins the densities in each of the N time intervals as measured in the specified channel over the measurement duration.
• the Bin Offset 206 indicates the position of the first bin, expressed in microseconds.
• the Bin Interval 207 indicates the time interval during which Medium Sensing Events are counted to be in this bin, expressed in slot times. Medium Sensing Events are defined in Table 5.
• the Number of Bins 208 indicates the total number of time intervals that are covered by the time histogram.
• the Total Number of Medium Sensing Events 209 indicates how many events have been counted during the measurement.
• a histogram is generated that represents the probability distribution of Medium Sensing Events in time.
• the present invention provides a mechanism for storing these reports and locally obtained measurements by a STA in its MIB Table that can be implemented within its existing processing logic under the control of its SME.
• the present invention is directed to an apparatus and method for a wireless radio device to capture a history of Medium Sensing Time Histogram Reports.
• the present invention defines a format for storing locally generated and received Medium Sensing Time Histogram Reports over time as a sequence of entries in a MIB Table of a STA.
• FIG. 1 illustrates a Medium Sensing Time Histogram Request format
• FIG. 2 illustrates a format of a Medium Sensing Time Histogram Report according to an embodiment of the present invention
• FIG. 3 is a simplified block diagram illustrating the architecture of a wireless communication system whereto embodiments of the present invention are to be applied
• FIG. 4. illustrates a simplified block diagram of a wireless device of the communication system of FIG. 3 modified to perform at least one of obtain locally and request from another network device a Medium Sensing Time Histogram Report and store it locally, according to an embodiment of the present invention
• FIG. 5 illustrates a format of a MIB Table entry for a Medium Sensing Time Histogram Report Table according to an embodiment of the present invention
• FIG. 6 is a flow chart illustrating the operation steps of receiving a request for a Medium Sensing Time Histogram Report, sensing the medium and generating a Medium Sensing Time Histogram Report, and storing it as an entry in a Medium Sensing Histogram Report table of a MIB Table and finally transmitting it over the medium; and
• FIG. 7 is a flow chart illustrating the operation steps of requesting and receiving ov er the medium a Medium Sensing Time Histogram Report, sensing the medium locally and generating a local Medium Sensing Time Histogram Report, and storing the generated and received reports as an entry in a Medium Sensing Histogram Report table of a MIB Tab le.
• FIG. 3 illustrates a representative network environment whereto embodiments of the present invention are to be applied.
• a wireless device 301 is communicates with a plurality of wireless devices 301 through a wireless link in which the wireless devices are communicated with each other via a plurality o f wireless channels.
• a key principle of the present invention is provide a mechanism to store, i.e., MIB Table, a sequence of at least one of a locally sensed and received from other wireless devices sequence of at least one Medium Sensing Time Histogram Report as at least one entry in a Medium Sensing Time Histogram Report Table defined by the present invention as a type of table that can be stored in a MIB Table.
• the wireless devices 301 within the WLAN of FIG. 3 may include a system with an architecture that is illustrated in the block diagram of FIG. 4.
• Each wireless device 301 may include a receiver 401, a processor 402, a time histogram management module 405, a memory 403 having a MIB Table 404, a timer 406 and a transmitter 407.
• the exemplary system 400 of FIG. 4 is for descriptive purposes only. Although the description may refer to terms commonly used in describing particular wireless devices, the description and concepts equally apply to other processing systems, including systems having architectures dissimilar to that shown in FIG. 3.
• the receiver 401 and the transmitter 407 are coupled to an antenna (not shown) to receive and transmit time histogram reports, requests therefor, and to sense the medium for local generation of time histogram reports.
• the processor 402 controls the time histogram management module 405 in the storage and retrieval of each Medium Sensing Time Histogram Report Entry in a 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 the Medium Sensing Time Histogram Report Table as a first -in-first-out data table to preserve currency of the entries. Further, in a preferred embodiment Medium Sensing Time Histogram Report Entries that have been received by the station management entity (SME) of the radio device are kept in the Medium Sensing Time Histogram Report Table for a predetermined minimum. In an implementation that is compliant with IEEE 802.11k standard this minimum retention time is dotl lMeasurementReportAgingTime after having been written in the MIB. After this predetermined amount of time since a report was written, the report entry can be erased by SME to free memory.
• SME station management entity
• FIG. 5 illustrates a Medium Sensing Time Histogram Report Entry in a Medium Sensing Time Histogram Table contained in a MIB Table according to th e present invention.
• An example of a software implementation of a Medium Sensing Time Histogram Report Table according to the present invention is contained in Appendix I.
• Each entry in the Medium Sensing Time Histogram Report Table according to the pres ent invention comprises all the fields of the Medium Sensing Time Histogram Report illustrated in FIG.
• Index 501 Index 501
• RqtsToken 502, Iflndex 503, and STAAddr 504 and the Bin Densities 210 through 21(N-1) are stored in a Bin Table 505 indexed by Bin i Index 506i for 1 0, ..., N-1.
• a predetermined number of Medium Sensing Time Histogram Report entries can be stored in the MIB table. This predetermined number is ten.
• a radio device e.g., a STA, reports measurements using a Measurement Report element.
• the format of a Measurement Report field of each Medium Sensing Time Histogram Report entry is shown in FIG. 5.
• the subfields are defined as follows: a. Each entry in the Table is indexed by Index. b.
• the Request Token holds the request token that was specified in the measurement request that requested the measurement report corresponding to this entry and is an exact match to the original request token attribute.
• the Interface Index is the interface index that the report corresponding to this entry was received on.
• the STA Address is the MAC address of the measuring STA that made the measurements reported in the report corresponding to this entry.
• the Channel Number indicates the channel number to which the Medium Sensing Time Histogram Report applies.
• the Channel Band indicates the measured frequency band, taken from Table 2, in which the Channel Number applies.
• g. -The Measurement Duration shall be set equal to the duration over which the Medium Sensing Time Histogram Report was measured, expressed in TUs.
• the Medium Sensing Measurement Subtype indicates the subtype of Medium Sensing Time Histogram Report, as defined in Table 6.
• the RPI Threshold identifies a received power level threshold according to Table 7, as seen at the antenna connector.
• the RPI Threshold is used to determine if a Medium Sensing Event occurs, while collecting information for the RPI Time Histogram.
• the Medium Sensing Time Histogram Report contains the densities in each of the N time intervals as measured in the specified channel over the measurement duration.
• the Total Number of Medium Sensing Events 209 indicates how many events have been counted during the measurement.
• the Medium Sensing Events are defined in Table 8.
• the Bin Table stores indexed Bin i densities by storing N pairs comprising the Bin i index and the associated Bin i density.
• FIG. 6 illustrates a flow diagram 600 of the operation steps performed by a wireless device 301 receiving a Medium Sensing Time Histogram Measurement Request 601, sensing the medium and generating a local Medium Sensing Time Histogram Report 602, storing the report FIFO in a local MIB as a Medium Sensing Time Histogram Report entry while purging out-of-date entries in the MIB (if needed) 603, and transmitting over the medium the report with the device's address contained therein 604.
• FIG. 6 illustrates a flow diagram 600 of the operation steps performed by a wireless device 301 receiving a Medium Sensing Time Histogram Measurement Request 601, sensing the medium and generating a local Medium Sensing Time Histogram Report 602, storing the report FIFO in a local MIB as a Medium Sensing Time Histogram Report entry while purging out-of-date entries in the MIB (if needed) 603, and transmitting over the medium the report with the device's address contained therein 604.
• FIG. 7 illustrates a flow diagram 700 of the operation steps performed by a wireless device 301 requesting a Medium Sensing Time Histogram Measurement Report 701, sensing the medium and generating a local Medium Sensing Time Histogram Report with the local device's address contained therein 702, receiving over the medium a report with the measuring device's address contained therein 703, and storing the report(s) FIFO in a local MIB as a Medium Sensing Time Histogram Report entry while purging out -of-date entries in the MIB (if needed) 704.
• dotllMedSenseT meHistogramReportTable OBJECT -TYPE SYNTAX SEQUENCE OF dotllMedSenseTimeHistogramReportEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Group contains the current list of Medium Sensing Time Histogram report entries that have been received by the SME.
• the report tables shall be maintained as FIFO to preserve freshness , thus this attribute can be overridden by memory constraints or other implementation constraints determined by the vendor of this SME.
• DotllMedSenseTimeHistogramReportEntry SEQUENCE ⁇ dotllMedSenseTimeHistogramReportlndex Uns ⁇ gned32, dotllMedSenseTimeHistogramReport RqstToken OCTET STRING, dotllMedSenseTimeHistogramReportlfIndex Interfacelndex, dotllMedSenseTimeHistogramMeasu ⁇ ngSTAAddr MacAddress, dotllMedSenseTimeHistogramReportChanNumber INTEGER, dotllMedSenseTimeHistogramReportChanBand INTEGER, dotllMedSenseTimeHistogramReportActualStartTime TSFType, dotllMedSenseTimeHistogramReport MeasurementDuration Unsigned32, dotllMedSenseTimeHistogramReportSubtype INTEGER, dotllMedSenseTimeHistogramReportRPIThreshold INTEGER, dotllMedSenseTimeHistogramReportBinOffs et INTEGER, dotllMedSenseTime
• dotllMedSenseTimeHistogramReportRPIThreshold OBJECT -TYPE SYNTAX INTEGER (0..7) MAX -ACCESS read-only STATUS current DESCRIPTION "This attribute indicates the RPI threshold that was used for generating this row of MedSenseTimeHistogramReport . 0: -87dBm observed at antenna 1: -82dBm observed at antenna 2: -77dBm observed at antenna 3: -72dBm observed at antenna 4: -67dBm observed at antenna 5: -62dBm observed at antenna 6: -57dBm observed at antenna other values are reserved.” : : ⁇ dotllMedSenseTimeHistogramReportEntry 10 ⁇
• dotllMedSenseTimeHistogramReportEntry 13 ⁇ dotllMedSenseTimeHistogramReportNumEvent OBJECT -TYPE SYNTAX INTEGER MAX-ACCESS read-only STATUS current DESCRIPTION "This attribute indicates the number of medium sensing events . The purpose of this value is to allow the calculation of absolute times, as well as providing a confidence indicator.” ⁇ dotllMedSenseTimeHistogramReportEntry 14 ⁇
• dotllMedSenseTimeHistogramReportBinTable OBJECT -TYPE SYNTAX SEQUENCE OF dotllMedSenseTimeHistogramReportBinEntry MAX -ACCESS not-accessible STATUS current DESCRIPTION "Group contains the list of bin entries that are part of this time histogram.” : : ⁇ dotllMedSenseTimeHistogramReportEntry 15 ⁇
• DotllMedSenseTimeHistogramReportBinEntry SEQUENCE ⁇ dotllMedSenseTimeHistogramReportBinlndex Unsigned32 , dotllMedSenseTimeHistogramReportBinDensity INTEGER ⁇
• dotllMedSenseTimeHistogramReportBinln dex OBJECT-TYPE SYNTAX Unsigned32 MAX -ACCESS read-only STATUS current DESCRIPTION " Index for Medium Sensing Time Histogram Report Bin Table entries in dotllMedSenseTimeHistogramReportBinTable, greater than 0." :: ⁇ dot llMedSenseTimeHistogramReportBinEntry 1 ⁇
• dotllMedSenseTimeHistogramReportBinDensity OBJECT -TYPE SYNTAX INTEGER (0..255) MAX -ACCESS read-only STATUS current DESCRIPTION "This attribute indicates the probability of medium sensing events during the bin interval.” :: ⁇ dotllMedSenseTimeHistogramReportBinEntry 2 ⁇

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• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Mobile Radio Communication Systems (AREA)
• Small-Scale Networks (AREA)

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Citations (2)

• 2004
  • 2004-10-12 WO PCT/IB2004/052072 patent/WO2005036823A2/en not_active Application Discontinuation
  • 2004-10-12 EP EP04770242A patent/EP1676400A2/en not_active Withdrawn
  • 2004-10-12 JP JP2006534895A patent/JP2007522691A/ja active Pending
  • 2004-10-12 KR KR1020067008393A patent/KR20060097023A/ko not_active Application Discontinuation

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