AU2007231881A1 - Wireless communication method and apparatus for implementing access point startup and initial channel selection processes - Google Patents

Description

P001 Section 29 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Wireless communication method and apparatus for implementing access point startup and initial channel selection processes The following statement is a full description of this invention, including the best method of performing it known to us: WIRELESS COMMUNICATION METHOD AND APPARATUS

O

OFOR IMPLEMENTING ACCESS POINT STARTUP AND INITIAL CHANNEL SELECTION PROCESSES 0 00 FIELD OF THE INVENTION The present invention relates to a wireless communication system. More particularly, the present invention relates to initializing operating parameters and 00 o00 selecting the most appropriate operating channel for an access point (AP).

BACKGROUND TO THE INVENTION OThe conditions of a radio link under which a wireless communication system operates may change at any time. Since a wireless transmit/receive unit (WTRU) is mobile, the WTRU may be out-of-range, or within range of one or more APs depending upon the position of the WTRU. When an AP is newly established, or powers up again after powering down for some reason, the startup process of the AP must evaluate its radio resource environment. Typically, the startup process also provides a mechanism for announcing itself to other APs of its own extended service set (ESS) such that the other APs can self-adjust their own operating parameters accordingly.

There are several current schemes that are employed in order to increase the capacity of a wireless communication system. Channel, frequency, selection is one of such schemes, whereby one or more APs in a network select one or more channels to communicate with their associated WTRUs.

Coordination of AP channel selection is usually performed manually. However, it is very impractical to manually coordinate channel selection in response to every small change in the network configuration since it may cause a redesign and reconfiguration of all APs. Unlicensed spectra and external sources of interference also raise problems that are not adequately addressed by manual coordination. Moreover, it is difficult for manual channel selection to assign channels such that the traffic loads of neighboring APs are shared among the available channels in a way that maximizes overall system capacity.

Another problem with prior art schemes is encountered when a multiple APs attempt to power-up simultaneously. When this occurs within a network, all of the APs try to make a channel selection at the same time. Thus, the channel selection by the APs would not be optimal since each AP does not take into account the channel selection of neighboring APs.

A method and system which overcomes the above-mentioned problems 0 Z would be greatly beneficial.

00 SUMMARY OF THE INVENTION The present invention provides a method and apparatus for implementing 00oo 00oo startup and initial channel selection processes for an AP.

t' The startup process of the AP includes a path loss discovery phase and an announcement phase. During the path loss discovery phase, the AP detects Cneighboring APs from its own ESS, neighboring APs from different ESSs, and external sources of interference. During the announcement phase, the AP transmits a beacon signal in order to accelerate recognition by neighboring APs also running the path loss discovery phase. The startup process provides the AP with the ability to monitor and evaluate its radio environment, and therefore allows the AP to self-determine initial operating parameters.

An initialization channel selection process for an AP is automatically implemented when the AP's startup process begins.

In accordance with one aspect of the present invention there is provided a method for optimizing the selection of channels used by an access point the method including: determining a maximum allowed interference MAx on any given channel based on a baseline range of the AP where IMAX PMAX,, -RNG I, -M,,PMAX is the maximum transmission \/11e h igh power of the AP, RNGb,,, is the range covered by the AP, is the e)q h igh required carrier power-to-interference ratio of a high rate packet, and M, is a margin to eliminate channels with interference levels too close to the actual maximum allowed level; selecting candidate channels for use by the AP, wherein the interference of the selected candidate channels is less than Im; and selecting a channel among the candidate channels based on a certain criteria.

In accordance with another aspect of the present invention there is 0 provided apparatus for optimizing the selection of channels, the apparatus including: 0 Z an access point (AP) configured to determine a maximum allowed 0 0 interference IM. on any given channel based on a baseline range of the AP where IM PM- RNGba-(Ce is the maximum 0 0 o transmission power of the AP, RNGb. is the range covered by the AP, is the required carrier power-to interference ratio of a high rate packet, and M, is a margin to eliminate channels with interference C levels too close to the actual maximum allowed level; the AP configured to select candidate channels for use by the AP, wherein the interference of the selected candidate channels is less than IMAX and the AP configured to select a channel among the candidate channels based ion a certain criteria.

In accordance with another aspect of the present invention there is provided An access point (AP) for optimizing the selection of channels, the AP including: an integrated circuit (IC) configured to determine a. maximum allowed interference IMAX on any given channel based on a baseline range of the IP where ImAx PA -RNG, I) -M,,PM is the maximum transmission power of the AP, RNGb, is the range covered by the AP, is the required carrier power-to-interference ratio of a high rate packet, and M, is a margin to eliminate channels with interference levels too close to the actual maximum allowed level; the IC configured to select candidate channels for use by the AP, wherein the interference of the selected candidate channels is less than IAX and the IC configured to select a channel among the candidate channels based on a certain criteria BRIEF DESCRIPTION OF THE DRAWINGS SA more detailed understanding of the invention may be had from the following description, given by way of example and to be understood in 0 Z conjunction with the accompanying drawings wherein: 00 Figure 1 is a block diagram of a wireless communication system in accordance with the present invention; Figure 2 is a flow diagram of a startup process of an AP according to one 00 00oO embodiment of the present invention; t' Figure 3 is a flow diagram of an automatic channel selection process according to another embodiment of the present invention; and Figure 4 is a flow diagram of an initialization channel selection process in accordance with yet another embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT Hereafter, the terminology "WTRU" includes but is not limited to a user equipment mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment.

Hereinafter, the terminology "AP" includes but is not limited to an access point, a base station, Node-B, site controller, or any other type of interfacing device in a wireless environment.

The features of the present invention may be incorporated into an IC or be configured in a circuit comprising a multitude of interconnecting components.

The present invention as described herein, is generally applicable to wireless local area network (WLAN) technologies, as applied to the IEEE 802.11 and ETSI HyperLAN specifications in general, but is envisaged to be applicable to other interference-limited wireless systems such as IEEE 802.15 and IEEE 802.16.

Figure 1 is a block diagram of a wireless communication system 100 according to the present invention. The wireless communication system 100 comprises an AP 105 and a plurality of WTRUs 110a-110n. The AP 105 communicates with the WTRUs 110a-110n over a wireless link 115 via an antenna 120. The AP 105 includes a transceiver 125, a channel selector 130, a measuring unit 135, a power controller 140, a timer 145 and a memory 150. The transceiver 125 transmits signals 115a-115n to, and receives signals 115a-115n from, the WTRUs 11 Oa-11 On via the antenna 120.

The channel selector 130 selects a channel which is used for 0 z communication with each WTRU 110a-110On. The measuring unit 135 measures 00 operating parameters for supporting the AP 105. The measuring unit 135 is responsible for collecting, processing and storing channel measurements including, but not limited to: the channel utilization percentage of time that the 00oo 00oo channel is busy), the level of external (non 802.11) interference, the received Ssignal strength measured on received packets, and the like. The power controller 140 controls the transmission power of the AP 105. The timer 145 sets one or Cmore predetermined periods during which the AP 105 performs certain operations.

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The memory 150 provides storage for the AP 105, including recording data such as results of the measurements.

Figure 2 is a flow diagram of a startup process 200 of the AP 105 including a discovery phase 210 and an announcement phase 220. In the discovery phase 210, the AP 105 initializes its measurement parameters and values (step 211).

The measurement parameters and values that are initialized may, for example, include the parameters and values listed in the following Table 1. As those of skill in the art would realize, other parameters and values may be used, in addition to, or in place of, these parameters and values.

Symbol Description Type Default value ACS Allowable Channel Set Configuration 6, 11} parameter TrDicover Discovery phase value of the Configuration 1000 ms mpp fy fixed component of the Silent parameter Measurement Period generation interval TDiscover Discovery phase value of the Configuration 0 ms mpp var amplitude of the variable parameter component of the Silent Measurement Period generation interval TDiscover Discovery phase value of the Configuration 1000 ms mpp _dur duration of a Silent parameter Measurement Period NDiscove Minimum number of Configuration 4 MIN MS measurement sets during the parameter Discovery Phase NDscover Maximum number of Configuration MAX MS measurement sets during the parameter Discovery phase TrAnouce Announcement phase Configuration 10 seconds dur duration parameter TAnnounce Beacon transmission period Configuration 100 ms beacon during Announcement phase. parameter PM Maximum AP transmission Configuration 20 dBm power parameter Table 1.

In step 212 of the discovery phase 210, the measuring unit 135 measures the operating parameters by performing N ,'"cov measurement sets, whereby measurements are taken sequentially on each channel in an allowable channel set (ACS) for a period of time during a measurement set which consists of a

I

complete cycle of measurement periods through all channels in the ACS. The Soperating parameters, for example, may be the transmission power and the channel setting of the AP 105. It is preferable that the overall measurement 0 Z duration on each channel, which corresponds totc x Nis set such that 00 enough loud packets are received from neighboring APs. The loud packets are the packets that are sent at maximum power by an AP to increase the likelihood of its being detected by its neighboring APs.

The duration of TDoV e is set such that it is long enough to limit edge mpp fix N effects, which occur when a packet is in transmission during transition between measurement periods (MPs). It is also preferable for the o be set to a measurementtoTbe set to duration short enough to allow continuous cycling between frequencies so that the AP 105 can detect a channel change by one of its neighbors. The duration and periods are determined by the timer 145. The duration of the discovery phase 210 consists of a random number of measurement sets, uniformly distributed between NDicor and N Discover The duration of the discovery phase 210 is random to account for the case where two or more APs are powered-up simultaneously, avoiding that initial frequency selection be performed at the same time for these APs.

As a result of these measurements, the AP 105 can determine its radio environment, such as a detection of neighboring APs from its own ESS, a detection of neighboring APs from different ESSs, and a detection of external sources of interference.

Referring back to Figure 2, once the NDic,,er performance measurement sets have been completed (step 212), the power controller 140 invokes power control for the AP 105 (step 213). The power control determines a baseline range of the AP 105 and a related baseline power setting. After the power control of the AP 105 is invoked at step 213, the channel selector 130 invokes a channel optimization process (step 214) to select channels that a particular AP or network of APs use. The initial channel setting of the AP 105 is determined based on parameters that are determined by the power controller 140.

During the discovery phase 210, the AP 105 remains silent, the AP 105 does not transmit any packets). Upon completion of the discovery phase 210, the AP 105 has gathered enough information to determine an optimal operating Schannel and select a transmission power setting.

After the discovery phase 210 ends, an announcement phase 220 follows.

0 Z During the announcement phase 220, the AP configures its operating channel to 00 the optimal channel determined at the end of the discovery phase 210. It should be noted that other processes may be performed in the interim as necessary. The purpose of the announcement phase 220 is to accelerate the detection of the AP o00 o00 by its neighboring APs. In the beginning of the announcement phase 220, various Cc, parameters, Tzb""°ce, PM), and are initialized (step 221). During the announcement phase duration T A c the AP 105 only transmits beacon Sframes having a maximum transmission power Pm with period (step 222). This accelerates the detection of the AP 105 by other APs, because only maximum power packets are transmitted. During the announcement phase 220, WTRUs beyond the coverage range of the AP 105 may attempt to associate with the AP 105, because the AP 105 is transmitting at its maximum powerP,,. For this reason, all association requests from WTRUs are denied during the announcement phase 220 in order to avoid associating a WTRU that will be out of range during normal operation.

Once the announcement phase 220 ends, the startup of the AP 105 is complete. The AP 105 then configures itself for its normal operation (step 223) and begins normal operation (step 230). The AP 105 sets its transmission power to the setting determined by the power controller 140, after which the AP 105 begins normal operation and starts accepting association requests from the WTRUs 110.

Figure 3 is a flow diagram of an automatic initialization channel selection process 300 according to one embodiment of the present invention. In the preferred embodiment, the channel selection process is invoked at the end of the discovery phase 210, where measurements on each channel have been taken.

Channels are chosen for use by a particular AP, or a network of APs. Channel selection can be done either manually or automatically, and can be initiated at deployment or performed dynamically during operation. The present invention may be implemented in conjunction with wireless local area network (WLAN) applications, in accordance with IEEE 802.11.

The initialization channel selection process 300 is performed during the Sstartup process 200 and determines the best operation channel. In the preferred embodiment, channels are being scanned during the discovery phase 210. At the 0 z end of the discovery phase 210, the channels selection process is invoked in step 00 214 to select the best channel based on the measurements observed on each channel during the discovery phase 210. In all cases, the initialization channel selection process 300 scans a plurality of channels channels 1-11) to detect 00oO 00oO the best channel available. The sequence of scanned channels may be in a Spredetermined order, or it may be random. The channel sequence does not need r- to include all available channels. For each channel scanned, the process determines: 1) what other APs are operating on that channel; 2) whether the APs are part of the same system, according to the ESS); 3) the signal strength of the APs; 4) the amount of traffic on the channel; and 5) if there are any other sources of interference on the channel, non-802.11 interference), and the received power level on non-WLAN interference. After the scanning is complete, the AP can calculate which channel would give the best performance, the channel that has the least amount of interference). The AP then retunes itself to that channel. Depending on whether the other APs detected are part of the same system, the AP can decide to be more or less aggressive in the choice of channel to use.

In an alternate embodiment, coordinated frequency selection may be accomplished by: 1) having APs exchange information with each other about their properties load, capabilities or position); or 2) having a centralized scheme that can obtain information from each AP, and setting the channel of all APs in the network. For the first case, the decision is still made autonomously by each AP, but the information exchanged can allow a better decision it can include statistics that are difficult to observe externally by another AP). For the second case, information is gathered from the different APs and communicated to a centralized unit or device, which upon reception of the information takes a decision and communicates the decision back to the different APs.

Referring still to Figure 3, when the initialization channel selection process 300 is initiated (step 305), the AP 105 is allowed to scan all channels to detect the identity and a received signal strength indicator (RSSI) of all APs in the vicinity (step 310). In the preferred embodiment, step 310 may be implemented during the discovery phase 210. In step 315, the channel list is scanned. All, or a Sportion, of the listed channels may be sequentially scanned in a predetermined or random order. Information associated with each AP detected on each channel is 0 Z recorded (step 320). This information may include, but is not limited to, the 00 identity of other APs which are operating on the scanned channel, an indication of whether other APs are part of the same ESS, the signal strength of the APs, the amount of traffic on the channel and whether there are any other sources of 00oo 00oo interference on the channel.

Cc After the scanning is complete, the AP 105 determines which channel provides the best performance (step 325). This may be determined, for example, Cby measuring which channel has the least amount of interference or whether other APs are part of the same ESS. Once the channel having the best performance is determined, the AP 105 tunes itself to the best channel.

Figure 4 is a detailed flow diagram of an initialization channel selection process 400 used to determine the best channel upon AP startup according to another embodiment of the present invention. The initialization channel selection process 400 includes a candidate channel determination process 405 and a channel selection process 450.

In the candidate channel determination process 405, the AP 105 retrieves the maximum allowed interference IMAx (step 410), which is the maximum allowed interference on any given channel determined based on the baseline range of an AP. may be obtained from the power control process. IMAX is calculated by the initialization channel selection process 400 using Equation (1) below. Some of the parameters that are used in Equation are retrieved from the power control process. Specifically, power control will determine RNG,.

P, (C )g and M, on the other hand are pre-determined parameters.

,eq high Preferably, IMAx for the candidate channel determination process 405 is calculated based on Equation as follows: I IPMoX RNG

-M;

MAX -RNG )req high Equation (1) where Pm. is the maximum transmission power of the AP 105; RNG,,e is the range covered by the AP 105; and C)q_ is the required carrier power-to- S interference ratio of a high rate packet, (for example 11 Mbps). M, is a margin to 00 eliminate channels with interference levels too close to the actual maximum allowed level. Alternatively, a pre-determined value of ImA x may be used to determine the list of candidate channels.

00oO 00oO A first channel is selected from an ACS (step 415). Interference I of a Cc channel is measured and compared with the maximum allowed interference ',M (step 420). If the interference I of the channel is less than the maximum allowed c- interference MA, the AP 105 records the channel in a candidate list in the memory 150 (step 425). If the interference I of the channel is not less than the maximum allowed interference IMAX the AP 105 checks whether any more channels in the ACS exists (step 430). If more channels in the ACS exist, the AP 105 selects next channel from the ACS (step 435) and the candidate channel determination process 405 then returns to step 420.

If no more channels exist in the ACS, the AP 105 checks whether any candidate channel is available (step 440). If, in step 440, it is determined that no candidate channel is available, the AP 105 increases IMx by AdB (step 445) and the candidate channel determination process 405 returns to step 415. If, in step 440, it is determined that at least one candidate channel exists, the candidate channel determination process 405 is complete and the channel selection process 450 is then performed.

One criterion used by the channel selection process 450 is the number of neighboring BSSs that have been detected on each channel NB(k). Once the candidate channels are selected, the minimum number of detected beacons from different BSSs, among all candidate channels, NZ'N is determined (step 455).

The number of neighboring BSSs that have been detected on channel k, N

B

is compared with the minimum number of detected BSSs NMN and all channels fMIN reod for which N 8 NmB are removed from the list of candidate channels (step 460). In other words, only the channels with the minimum number of detected BSSs are retained. Alternatively, in steps 455 and 460, the number of detected neighbor BSSs on each channel could be replaced with the channel utilization on each channel. The channel utilization measurement corresponds to the percentage of time that the receiver is carrier locked by a WLAN signal. In this 0 case, the channel selection process would favor channels that have lower channel 00 utilization.

Another criterion used by the channel selection process is the minimum measured interference level, which is determined among all remaining candidate 00 00 channels (step 465). The minimum measured interference level on channel k I(k) and the minimum interference level ImIN are compared, and all channels for twhich l(k) ImN from the list of candidate channels are removed (step 470). In N other words, only the channels with the minimum interference level are retained.

If more than one candidate channel with the minimum interference level exists, a channel is randomly selected among the remaining candidate channels (step 475).

Exemplary parameters of the initialization channel selection process 400 are listed in the following Table 2. As those of skill in the art would realize, other parameters and values may be used in addition, or in place of, these values.

Default Symbol Description Type Value Value ACS Allowable channel set. Configuration {1,6,11} parameter NB(k) The number of neighboring BSSs Measurement NA detected on channel k. The minimum value of EDT is used to detect neighboring beacon frames.

1(k) The interference measured on Measurement NA channel k. I is measured as the average received signal power in the absence of "carrier lock" by the receiver the receiver is not receiving any packets).

RNGbe Baseline Range (set by the Path Internal NA Loss Discovery process) parameter Minimum required carrier power to Configuration 10 dB req interference ratio to support parameter maximum data rate.

PMAX Maximum AP transmission power Configuration 20 dbm parameter IMAX The maximum allowed Internal NA interference on any given channel parameter determined based on baseline range.

M1 Interference margin used in the Configuration 3dB calculation of the maximum parameter parameter allowable interference level, IAX A The amount, in dB, by which the Configuration 3 dB maximum allowed interference, Parameter IMAX, is increased if there are no candidate channels for which I

IMAX.

Table 2.

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone or in various combinations with or without other features and elements of the present invention.

Claims (18)

1. 2. The method of claim 1 wherein the candidate channels are selected from an allowable channel set (ACS).
2. 3. The method of claim 1 wherein step further includes: (cl) determining a number of detected beacons for each of the candidate channels; and (c2) selecting at least one of the candidate channels with a minimum number of detected beacons.
3. 4. The method of claim 1 wherein step further includes: (cl) determining the interference level of the candidate channels; and (c2) selecting at least one of the candidate channels with a minimum interference level. The method of claim 4 wherein step further includes: O (c3) selecting a channel randomly if there are at least two selected Scandidate channels. Z 6. Apparatus for optimizing the selection of channels, the apparatus 00oo including: an access point (AP) configured to determine a maximum allowed 00oo interference IMAX on any given channel based on a baseline range of the 00oo Cc AP where IM PMAX -G,e -MI, PmA x is the maximum where MX ~MAXreq ighI I A transmission power of the AP, RNG,, is the range covered by the AP, is the required carrier power-to interference ratio of a high rate packet, and M, is a margin to eliminate channels with interference levels too close to the actual maximum allowed level; the AP configured to select candidate channels for use by the AP, wherein the interference of the selected candidate channels is less than !MAX and the AP configured to select a channel among the candidate channels based ion a certain criteria.
4. 7. The apparatus of claim 6 wherein the AP determines a number: of detected beacons for each of the candidate channels, and the AP selects at least one of the candidate channels with a minimum number of detected beacons.
5. 8. The apparatus of claim 6 wherein the candidate channels are selected from an allowable channel set (ACS).
6. 9. The apparatus of claim 6 wherein the AP determines the interference level of the candidate channels, and the AP selects at least one of the candidate channels with a minimum interference level. The apparatus of claim 9 wherein the AP randomly selects a channel if there are at least two selected candidate channels. O 11. An access point (AP) for optimizing the selection of channels, the AP including: z an integrated circuit (IC) configured to determine a. maximum 00 allowed interference IMAX on any given channel based on a baseline range of the IP where IMA =PM-VRNG.,-( c /e -M,,PMAX is the maximum T transmission power of the AP, RNGe is the range covered by the AP, 00oO 00 VC is the required carrier power-to-interference ratio of a high rate Ireq _high packet, and M, is a margin to eliminate channels with interference levels Stoo close to the actual maximum allowed level; the IC configured to select candidate channels for use by the AP, wherein the interference of the selected candidate channels is less than MAX and the IC configured to select a channel among the candidate channels based on a certain criteria.
7. 12. The apparatus of claim 11 wherein the candidate channels are selected from an allowable channel set (ACS).
8. 13. The apparatus of claim 11 wherein the IC determines a number of detected beacons for each of the candidate channels, and the IC selects at least one of the candidate channels with a minimum number of detected beacons.
9. 14. The apparatus of claim 11 wherein the IC determines the interference level of the candidate channels, and the IC selects at least one of the candidate channels with a minimum interference level. The apparatus of claim 14 wherein the IC randomly selects a channel if there are at least two selected candidate channels. C 1. In a wireless communication including at least one access point (AP) in o communication with a plurality of wireless transmit/receive units (WTRUs), a Z method for optimizing the selection of channels used by the AP, the method 00 0comprising: determining candidate channels used for supporting communication oo performed by the AP; and oo 0(b) selecting a channel among the candidate channels based on a certain t'q C criteria, wherein steps and are automatically performed upon activating the AP. 2. The method of the claim 1 wherein the candidate channels are chosen from an allowable channel set (ACS) if a detected interference of each candidate channel is less than an established maximum allowed interference. 3. The method of the claim 1 wherein step further comprises: (bl) determining a minimum number of detected beacons which the candidate channels detects; and (b2) selecting a channel with the minimum number of detected beacons among the candidate channels. 4. The method of the claim 1 wherein step further comprises: (bl) determining the minimum interference level which candidate channels receive; and (b2) selecting a channel with the minimum interference level among the candidate channels. The method of the claim 1 wherein step further comprises selecting a channel randomly if there are at least two selected channels. 6. An access point (AP) for communicating with a plurality of wireless transmit/receive units (WTRUs) in a wireless communication system, the AP comprising: O a measuring unit for measuring operating parameters of each channel Sin an allowable channel set (ACS) upon activating the AP; a power controller for controlling transmission power of the AP based on the operating parameters; oO a channel selector for selecting a channel used by the AP for communication based on the measured operating parameters; 00oO a timer for setting a time period during which a beacon frame is 00oo transmitted from the AP to announce the operating parameters to other APs; and t'q N a memory for storing the measured operating parameters. N 10 7. The AP of claim 6 wherein the beacon frame is transmitted to the other APs at its maximum power during the time period. 8. The AP of claim 6 wherein candidate channels are chosen from an allowable channel set (ACS) if an interference level of the candidate channels is less than a maximum allowed interference on the channel. 9. A startup method for an access point (AP) in a wireless communication system, the method comprising: obtaining operating parameters of the AP upon activating the AP; performing initial operation of the AP based on the operating parameters; and announcing the operating parameters of the AP to other APs. The method of the claim 9 wherein step of further comprises: (al) initializing the operating parameters of the AP; and (a2) measuring the operating parameters during a predetermined time period. 11. The method of the claim 9 wherein step further comprises: (bl) performing a power control of the AP based on the operating parameters measurements; and (b2) performing a channel selection based on the power control. O 12.The method of the claim 9 wherein step is performed by the AP sending Sbeacon frames at its maximum transmission power during a predetermined time O period. o00 13. In a wireless communication including a plurality of access points (APs), a method of automatically selecting an initial channel for use by a particular AP, the oo method comprising: oo scanning a plurality of channels the AP will use to communicate; t'q N recording information associated with an AP detected on each scanned channel; and C 10 based on the recorded information, selecting one of the scanned channels having the best performance. 14.The method of the claim 13 wherein the recorded information includes one or more of the following: a signal strength of the channel, an amount of traffic on the channel, sources of interference on the channel, an indication of whether other APs are operating on the channel, and whether other APs are part of the same extended service set (ESS). access point (AP) comprising: means for obtaining operating parameters of the AP when activated; means for performing initial operation of the AP based on the operating parameters; and means for announcing the operating parameters of the AP to other APs.
10. 16.The AP of claim 15 wherein the obtaining means further comprises: (al) means for initializing the operating parameters of the AP; and (a2) means for measuring the operating parameters during a predetermined time period.
11. 17.The AP of claim 15 wherein the performing means further comprises: O (bl) means for performing a power control of the AP based on the Smeasurement; and (b2) means for performing a channel selection based on the result of the power control. oO
12. 18. An access point (AP) comprising: 00 means for determining candidate channels used for supporting 00oo communication performed by the AP; and t'q means for selecting a channel among the candidate channels based on a certain criteria, wherein the steps and are automatically N 10 performed upon the activating of the AP.
13. 19.The AP of claim 18 wherein the channel selecting means comprises: (bl) means for determining a minimum number of detected beacons which the candidate channels detects; and (b2) means for selecting a channel with the minimum number of detected beacons among the candidate channels. access point (AP) for selecting a channel from a list of candidate channels, the AP comprising: means for determining a minimum number of detected beacons associated with the candidate channels; and selecting from the list one or more channels with the minimum number of detected beacons. 21 .The AP of claim 20 further comprising: means for determining a minimum interference level amongst the selected channels; and means for selecting at least one channel on the list with the minimum interference level.
14. 22.The AP of the claim 21 further comprising: S(e) means for selecting a channel randomly if there are at least two Sselected channels. Z 23.An integrated circuit (IC) for selecting a channel from a list of candidate 00 0channels, the IC comprising: means for determining a minimum number of detected beacons oo associated with the candidate channels; and oO 0(b) selecting from the list one or more channels with the minimum number t'q C of detected beacons. c 24.The IC of claim 23 further comprising: means for determining a minimum interference level amongst the selected channels; and means for selecting a channel on the list with the minimum interference level among the candidate channels. The IC of the claim 24 further comprising: means for selecting a channel randomly if there are at least two selected channels.
15. 26.An access point (AP) for selecting a channel from a list of candidate channels, the AP comprising: means for determining a minimum interference level amongst channels with a predetermined minimum number of detected beacons; and means for selecting a channel on the list with the minimum interference level among the candidate channels.
16. 27. The access point (AP) of the claim 26 further comprising: means for selecting a channel randomly if there are at least two selected channels.
17. 28.An integrated circuit (IC) for selecting a channel from a list of candidate channels, the IC comprising: r- o means for determining a minimum interference level amongst channels C with a predetermined minimum number of detected beacons; and 0 means for selecting a channel on the list with the minimum interference level among the candidate channels. 00
18. 29.The IC of the claim 28 further comprising: 00 means for selecting a channel randomly if there are at least two 00 selected channels. r--