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    • 专利摘要:
    PURPOSE: A wireless LAN(Local Area Network) with a channel swapping between DFS(Dynamic Frequency Selection) APs(Access Points) is provided to enhances a DFS algorithm used in the wireless LAN by adding a channel swapping mechanism. CONSTITUTION: A swap requesting AP(AP1) selects an optimum channel by mutually swapping channels with another AP using a channel swapping mechanism. The AP1 is operated on the first channel(C1) for calculating and storing a swap specific channel quality parameter(ssCSIQ) for every responding access point(AP2) operated on the second channel(C2). The swapping specific channel quality parameter(ssCSIQ) is calculated under the assumption that the AP2 and the AP1 have already swapped channels. The swap specific channel quality parameter(ssCSIQ) is used in the channel swapping mechanism.
    公开号:KR20020085853A
    申请号:KR1020020025368
    申请日:2002-05-08
    公开日:2002-11-16
    发明作者:부쉐패트릭；말호트라리차
    申请人:에이저 시스템즈 가디언 코포레이션；
    IPC主号:
    专利说明:

    WIRELESS LAN WITH CHANNEL SWAPPING BETWEEN DFS ACCESS POINTS}
    [9] The present invention relates to a communication system comprising a plurality of access points (APs) and network stations, each network station configured to communicate with one of the access points via a wireless communication protocol. The invention also relates to access points for such a communication system.
    [10] Wireless LANs have been developed as an improved replacement for wired LANs. In wireless LANs for data communication, a number of (mobile) network stations (eg, personal computers, telecommunication devices, etc.) with wireless communication functions have emerged. Compared to wired LANs, data communication in a wireless LAN may have more flexibility due to the flexibility of the placement of network stations in the area covered by the LAN and the absence of cable connections.
    [11] Wireless LANs are generally used according to a standard defined by ISO / IEC 8802-11 International Standard (IEEE 802.11). IEEE 802.11 describes a standard for wireless LAN systems operating in the 2.4-2.5 GHz ISM (industrial, scientific and medical) band. The ISM band is available worldwide and allows unlicensed operation for spread spectrum systems. In both the United States and Europe, the 2,400-2,483.5 MHz band is allocated, but in other countries, such as Japan, the 2.4-2.5 GHz ISM band is allocated. The IEEE 802.11 standard focuses on MAC (Media Access Control) and PHY (Physical Layer) protocols for AP-based networks and ad-hoc networks.
    [12] In AP-based wireless networks, stations within a group or cell may only communicate directly to the AP. The AP delivers a message to a destination station inside the same cell or to another AP through a wired distribution system for another AP, from which the messages finally reach the destination station. In ad-hoc networks, the stations operate at a peer-to-peer level and there is no AP or (wired) distribution system.
    [13] The 802.11 standard uses three PHY protocols: DSSS (Direct Sequence Spread Spectrum), FHSS (Frequency Hopping Spread Spectrum), and PPM (Pulse Position Modulation). All three of these PHYs offer bit rates of 1 and 2 Mbit / s, and IEEE 802.11 includes additional extensions 11a and 11b to allow higher bit rates. Extension 11b provides 5.5 and 11 Mbit / s bit rates in the same 2.4-2.5 GHz ISM band, as well as basic DSSS bit rates of 1 and 2 Mbit / s, while extension 11a provides 6 to 54 Mbit / bit in the 5 Ghz band. Provides a fast bit rate OFDM (Orthogonal Frequency Division Multiplexing modulation) PHY standard that provides bit rates in the s range.
    [14] The IEEE 802.11 basic MAC protocol is a random back-off time according to the carrier sense multiple access with collision avoidance (CSMA / CA) protocol and busy medium conditions allows the interoperability between compatible PHYs The IEEE 802.11 CSMA / CA protocol is designed to reduce the likelihood of collisions between multiple stations accessing the medium simultaneously. The random back-off scheme is used to resolve medium contention conflicts In addition, the IEEE 802.11 MAC protocol provides for fragmentation of packets, RTS / CTS polling conversations. defines special function operations for media reservation via interaction and point coordination (for time-bound services). The EEE 802.11 MAC protocol defines beacon frames transmitted at regular intervals by the AP to allow stations to monitor for the presence of the AP. It provides a set of management frames comprising Probe Request frames followed by Probe Response frames sent by available APs.The protocol provides for APs whose stations are operating on different frequency channels. Actively scan and allow the APs to show the station the parameter settings they are using.
    [15] Each DSSS AP runs on one channel. The number of channels depends on the regulatory domain in which the WLAN is used (e.g. 11 channels in the US in the 2.4 GHz band). The numbers can be found in ISO / IEC 8802-11, ANSI / IEEE Standard 802.11 1999-00-00. Overlapping cells using different channels can operate simultaneously without interference if the channel spacing is at least three. Non-overlapped cells can always use the same channels simultaneously without interference. Channel assignment can be dynamic or fixed. Dynamic channel allocation is desirable because the environment itself is dynamic.
    [16] In [Kamerman, December 1999], the dynamic allocation of channels is called dynamic frequency selection (DFS). The purpose of the DFS algorithm is to dynamically allocate channels of a WLAN in a manner that can achieve optimal performance. Performance is expressed in throughput, delay, and fairness. An AP with dynamic frequency selection can switch its channel to get a better operating channel. This will generally select the channel for less interference and channel sharing than the current channel.
    [17] In the algorithm of [Kamerman, December 1999], the amount of interference experienced by the AP in a particular current channel (X) is represented by a parameter (I (X)). Channel sharing is represented by a parameter CS (X). The values of CS (X) and I (X) are combined to calculate the so-called channel sharing and interference quality (CSIQ (X)). The value of CSIQ (X) measures the amount of interference and channel sharing belonging to a particular channel (X).
    [18] In [Kamerman, December 1999], if the value of CSIQ (Y) is equal to all values of CSIQ (X) for channels (X = 1, ... N, N is the number of available channels) If it is the highest among them, the AP switches to channel (Y). Thus, the best channel quality is represented by the highest CSIQ (X). The functionality of the DFS algorithm in [Kamerman, December 1999] will be described with reference to FIGS. 1A and 1B. The wireless LAN 1 shown in FIG. 1A includes a plurality of access points, where three access points AP1, AP2, and AP3 are shown. These access points are used as access points for their individual cells 3, 5, 7, which are each briefly depicted as circles surrounding their individual access points. In the initial situation, the access points AP1, AP2, AP3 communicate with their network stations via channels C1, C2, C3, respectively. The cells 3, 5, 7 may have different sizes. The cell size depends on the desired coverage area of the access point and the requirements of data throughput in the cell. The cell size can be controlled by appropriately setting the levels of the defer behaviour threshold and the carrier sense detection threshold, as known from EP-A-0903891. For example, one cell may include a number of network stations NS1, NS2 that require high throughput. In this case, the cell size must be small, whereby other network stations will be ignored as much as possible in the cell. In other cases, for example, there may be only a few network members that require low throughput inside a cell. Then, a single large cell containing these network stations will be sufficient to handle all data traffic associated with that cell. 1A shows the initial state of a wireless LAN 1 comprising three DFS-enabled APs. In the LAN 1, there are a plurality of network stations NS1, NS2, only two of which are shown here. In FIG. 1A, for example, the network station NS1 communicates all data traffic thereof with the access point AP1. The network station NS1 itself continuously monitors the communication quality (ie, the difference between the reception level and the average noise level) for communication with the access point AP1. As long as good communication quality to the associated access point AP1 is maintained, the network station NS1 maintains communication with AP1. When the communication quality decreases below a preset level, the network station NS1 starts searching for another cell 5 (access point AP2) to find a better communication quality. For this purpose, as is known to those skilled in the art, the network station NS1 probes the associated access point AP1 and all other access points within the area (ie AP2). In this procedure, the network station NS1 uses the beacon frames received from the associated access point AP1 and the signal reception level for probe responses from another access point AP2. The probe response frames are received by the network station NS1 subsequent to probe request frames sent by the network station NS1. As is known from IEEE 802.11, another access point AP2 is operated on a channel having a different frequency than the one access point AP1. The network station NS2 shown in FIG. 1A communicates with AP2. If the communication quality is reduced, the network station NS2 also starts searching for another cell to find a better communication quality, but will not find a better AP, so that the network station NS2 continues to communicate with the AP2. something to do.
    [19] 1B shows the case where a non-DFS access point AP4 using the channel 9 has reached within the area of the DFS-enabled AP1, for example. Using the DFS algorithm of [Kamerman, Dec. 1999], the access point AP1 operating on channel 10 is channel 4 or channel in order to have at least two channel spacings with all neighboring cells. Will be switched to (11).
    [20] The problem with the DFS algorithm described in [Kamerman, December 1999] is that it does not optimize the overall performance. All APs in a WLAN generally optimize only their performance and do not consider the performance of other APs. This is certain from the network point of view that the partitioning of channels for different APs will not be optimal. Thus, it is an object of the present invention to overcome channel selection problems that are not optimally performed.
    [21] The present invention relates to an access point of a WLAN communication network.
    [22] Observe his access point traffic load
    [23] Send probe requests and probe responses to other access points,
    [24] Receive probe requests and probe responses from other access points,
    [25] Include information on the traffic load in the probe responses
    [26] Compute and store the interference parameters for each of its plurality of possible channels
    [27] Compute and store channel sharing parameters for each of the plurality of channels
    [28] Using the interference and channel sharing parameters, calculate a normal channel quality parameter for each of the plurality of channels indicative of the amount of interference and channel sharing in each of the plurality of channels,
    [29] Using the regular channel quality parameters, dynamically select an optimal channel from a plurality of possible channels,
    [30] The access point is configured to select the optimal channel by mutually swapping channels with other access points using a swapping mechanism.
    [31] By introducing swapping options between adjacent access points, the present invention can improve the overall performance for the WLAN.
    [32] The invention also relates to a wireless LAN communication network comprising at least two access points as described above.
    [33] Moreover, the present invention relates to a method in which an access point selects an optimal channel in a WLAN communication network.
    [34] Observing his access point traffic load,
    [35] Sending probe requests and probe responses to other access points;
    [36] Receiving probe requests and probe responses from other access points,
    [37] Including information on the traffic load in the probe responses;
    [38] Computing and storing interference parameters for each of the plurality of possible channels thereof;
    [39] Computing and storing channel sharing parameters for each of the plurality of channels;
    [40] Using the interference and channel sharing parameters, calculate a normal channel quality parameter for each of the plurality of channels indicative of the amount of interference and channel sharing in each of the plurality of channels,
    [41] Dynamically selecting an optimal channel from a plurality of possible channels using the regular channel quality parameters,
    [42] The access point is configured to select the optimal channel by mutually swapping channels with other access points using a swapping mechanism.
    [43] The present invention also relates to a computer program loaded by an access point of a wireless LAN communication network, the program being connected to the access point,
    [44] Observe his access point traffic load
    [45] Send probe requests and probe responses to other access points,
    [46] Receive probe requests and probe responses from other access points,
    [47] Including information on the traffic load in the probe responses;
    [48] Computing and storing interference parameters for each of the plurality of possible channels thereof;
    [49] Computing and storing channel sharing parameters for each of the plurality of channels;
    [50] Using the interference and channel sharing parameters, calculate a normal channel quality parameter for each of the plurality of channels indicative of the amount of interference and channel sharing in each of the plurality of channels,
    [51] Providing the function of dynamically selecting an optimal channel from a plurality of possible channels using the regular channel quality parameters,
    [52] The access point is configured to select the optimal channel by mutually swapping channels with other access points using a swapping mechanism.
    [53] The invention also relates to a data carrier provided with a computer program as discussed above.
    [1] 1A shows cells of three APs in a conventional WLAN,
    [2] 1B shows cells of four APs in a conventional WLAN.
    [3] 1C illustrates cells of four APs in a WLAN described in the present invention.
    [4] 2 shows a diagram of a configuration of the present invention for a WLAN interface card.
    [5] 3 shows a simplified block diagram of the network station of the present invention.
    [6] 4 shows a simplified block diagram of an access point (AP) of the present invention.
    [7] 5 shows a flowchart for swapping the procedure of the requesting AP of the present invention.
    [8] Figure 6 shows a flow diagram for swapping the procedure of the responding AP of the present invention.
    [54] In FIG. 1C, a brief overview of the preferred embodiment is shown. The wireless LAN 1 includes a set of access points AP1, AP2, AP3 having overlapping cells 3, 5, 7. In this manner, (mobile) network stations can communicate with the AP in a continuous area. Adjacent to the LAN 1, there is a fourth access point AP4 accompanying the cell 9. As in the prior art and the case described in the FIG. 1B section, assume that AP4 is a non-DFS AP. However, it should be understood that AP4 may be any kind of radio source operating on channel C4. Circles 43 and 45 indicate locations where the reception level is the same as the lowest possible carrier detection threshold of the individual AP1 and AP2.
    [55] 2 shows a medium access controller (MAC) device 11 on a wireless LAN interface card 30 installed in the network stations NS1 and NS2 or a wireless LAN interface card 130 installed in the access points AP1 and AP2. An example of the configuration of the present invention is shown in a block diagram.
    [56] Here, the MAC device 11 includes a signal-processing unit 12, a signal reception level detection circuit 13, an antenna 31 and an on-board memory 14 which are necessary for explaining this embodiment of the present invention. Is shown briefly to show only. The MAC device 11 may include other members not shown here. In addition, the illustrated members 12, 13, 14 may be separate devices or integrated into one device. As desired, the devices may be implemented in the form of analog or digital circuits. The internal memory 14 may include RAM, ROM, FlashROM and / or other types of memory devices, as known in the art.
    [57] 3 shows a simplified block diagram of an embodiment of a network station NS1, NS2 including a processor means 21 involving peripheral devices. The processor means 21 stores memory units 18, 22, 23, 24 for storing instructions and data (e.g., floppy disks 19, CD ROMs 20, DVDs, etc.). One or more reading units 25, a keyboard 26 and a mouse 27 as input devices, and a monitor 28 and a printer 29 as output devices. Other input devices and other output devices may be provided, such as a trackball and touch screen. For data-communication via the wireless LAN 1, an interface card 30 is provided. The interface card 30 is connected to the antenna 31.
    [58] The illustrated memory unit includes a RAM 22, (E) EPROM 23, a ROM 24, and a hard disk 18. However, it will be appreciated that more / or other memory units known to those skilled in the art may be provided. In addition, one or more of these may be physically located remote from the processor means 21, if desired. The processor means 21 is shown in one box, but as is known to those skilled in the art, the processor means 21 can be located remotely from each other and comprise a number of processing units functioning in parallel or controlled by one main processor. Can be.
    [59] In an alternative embodiment of the invention, the network station 5, 6 may be a telecommunication device associated with the members of the interface card 30, as known to those skilled in the art.
    [60] 4 shows a simplified block diagram of one embodiment of an access point AP1, AP2, AP3 comprising a processor means 121 having peripheral devices. The processor means 121 stores memory units 118, 122, 123, 124 for storing instructions and data (e.g., floppy disks 119, CD ROMs 120, DVDs, etc.). One or more reading units 125, a keyboard 126 and a mouse 127 as input devices, and a monitor 128 and a printer 129 as output devices. For data-communication via the wireless LAN 1, an interface card 130 is provided. The interface card 130 is connected to the antenna 131. In addition, the access points AP1, AP2, AP3 are connected to the wired distribution network 140 via I / O means 132, for example, to communicate with other access points. The illustrated memory units include RAM 122, (E) EPROM 123, ROM 124, and hard disk 118. However, it will be appreciated that more / or other memory units known to those skilled in the art may be provided. In addition, one or more of these may be physically located remote from the processor means 121, if desired. The processor means 121 is shown in one box, but as is known to those skilled in the art, the processor means 121 may be located remotely from each other and comprise a plurality of processing units functioning in parallel or controlled by one main processor. Can be. In addition, other input / output devices other than the illustrated input / output devices (ie, 126, 127, 128, 129) may be provided.
    [61] In an alternative embodiment of the invention, the access points AP1, AP2, AP3 may be telecommunication devices associated with the members of the interface card 30, as known to those skilled in the art.
    [62] The appearance of the new access point AP4 shown in FIG. 1C causes sudden interference with AP1, because it uses channel C1 = 10 of AP1 and channel C4 = 9 having a channel spacing of less than three. Now, in accordance with the present invention, the access point AP1 determines the initiation of the swapping procedure.
    [63] 5 shows a flowchart of a swapping procedure for the request access point AP1. In the procedure of FIG. 5 above, the following parameters are used:
    [64] regCSIQ is a calculated quality parameter for all possible channels on which the AP can operate, and the value of this parameter is measured for both channel sharing and interference for that channel. The equation is given by regCSIQ (X) = CS (X) + CorFac x I (X). In contrast to CSIQ of [Kamerman, Dec. 1999], the lower the value of regCSIQ (X), the better the quality of channel X. Equations for CS (X) and I (X) can be found in [Kamerman, December 1999], and the parameter CorFac is a correction factor (preferably 1).
    [65] ccCSIQ (Swap Specific CSIQ) This is a specially calculated quality parameter. The equation is given by ssCSIQ (X) = regCSIQ '(X) + SwapPenalty, where regCSIQ' (X) is calculated in the same way as regCSIQ (X), but the responding AP has already It is computed under the assumption of use, that is, the assumption that swapping has already occurred. The swap penalty is a parameter that indicates that swapping is associated with any penalty. It may be 0, but it is preferred to have a positive value, for example 10.
    [66] At the start of the swapping procedure, the access point AP1 uses channel C1 = 10. In step 51, the request access point AP1 collects interference and sharing information by sending probe requests to other APs. Then, in step 52, AP1 computes regCSIQ values for all possible channels. In step 53, AP1 computes a swap specific CSIQ (ssCSIQ) for all channels used by any AP in response to the probe request. For the calculation of the swap specific CSIQ values, the expression for regCSIQ is used, but the response access points AP2 and AP3 assume that they use the channel on which the requesting AP operates, not the channel on which they actually operate.
    [67] The swap specific CSIQ value is increased by a predetermined amount (eg, by 10). Swap should not be executed unless necessary, due to the possibility of overhead costs. For example, by increasing the ssCISQ by 10, any channel carrying a regular CSIQ will be selected for switching and no swapping will be needed.
    [68] Now, in step 55, the lowest CSIQ is determined from all calculated regCSIQ values and all ssCSIQ values. If the lowest ssCSIQ is less than the lowest regCSIQ, the procedure moves to step 57. Otherwise, step 69 is executed. In step 57, AP1 calculates the difference between the lowest regCSIQ and the lowest ssCSIQ. The difference, called SwapBinPAP1, is a gain in AP1's performance if AP1 swaps channels (with the AP corresponding to the lowest ssCSIQ) instead of switching its channel to the channel corresponding to the lowest regCSIQ. . In step 59, a swap request is sent using the channel corresponding to the lowest ssCSIQ value. The swap request includes channel C1 of AP1 requesting the swap and also includes a value for SwapBinP AP1 . Now, in step 61, the access point AP1 waits for a swap response for a preset time period T_wait. If AP1 has received a swap response within T_wait ms, the result of step 63 is YES and proceeds to step 65. If the result of step 63 is NO, the next step is step 69, and the channel will be switched to channel C5 corresponding to the lowest regCSIQ.
    [69] In step 65, the swap response is checked. If the swap response is yes, proceed to step 67. This means that AP1 will change its channel to the value of one of the response access points AP2 (ie, C2). If in step 65 the swap response is no, step 69 is executed and AP1 will switch to channel C5.
    [70] 6 shows a flowchart of a swapping procedure for a response access point AP2. At the start of the procedure, the access point AP2 uses channel C2 = 6. At step 75, access point AP2 is operating normally and waiting for any swap request. If, at step 77, a request is received, AP2 proceeds to step 79. If no swap request is received, AP2 remains at 75. In step 79, the access point AP2 rescans all the channels to obtain probe responses of neighboring APs. During the examination of channel X, AP2 switches to the channel in question (i.e., X) and temporarily configures itself with the lowest delay threshold and bit rate to allow communication at the widest possible interval (Fig. 1C). Circle (45)). AP2 sends a probe request frame to obtain a probe response from all APs tuned to the channel within the wireless range in question. The probe response packets sent by the AP responding to the probe request carry information of load factors from each AP using the channel in question. Load information collected from all probe response APs along with reception levels of probe responses is stored by AP2. This is done for all channels and in the same way as in [Kamerman, December 1999].
    [71] Then, in step 80, the regCSIQ value for channel operation of AP2 is calculated. This means that regCSIQ (C2) is calculated. In step 81, the value of the ssCSIQ is calculated for the channel used by the swap request AP1. This means that ssCSIQ C1 is calculated using the load and reception level information stored by AP2 in step 79. Then, in step 83, the access point AP2 switches its channel to one of the swap requests AP1 (ie, C1). In step 85, the value of ssCSIQ (C1) is compared with the value of regCSIQ (C2). If the value of ssCSIQ (C1) is lower than the value of regCSIQ (C2), access point AP2 sends a swap response 'yes' in step 87. If ssCSIQ (C1) is not lower than regCSIQ (C2), the procedure will proceed to step 88. In step 88, the administrative domain (eg, company or organization) of AP1 is compared with the administrative domain of AP2. If the domains are not the same, step 90 is executed. If the two domains match, then step 89 is reached, where another, so-called "sacrifice" test is conducted. In this step, the (predicted) performance gain for the requesting AP1 (ie, SwapBinP AP1 ) is compared with the expected decrease in performance for AP2 (ie, ssCSIQ (C1) -regCSIQ (C2)). If the performance gain for AP1 is higher than the performance decrease for AP2, the access point AP2 sacrifices its channel and agrees to swap channels. This means proceeding to step 87. If the answer to step 88 is not the answer, go to step 90. This means that AP2 sends a swap response 'no' to the swap request AP1. AP2 then switches its channel back to C2 = 6 (see step 91).
    [72] The swapping procedure described above is not a low-overhead solution. So this should not be tried often. This should only be attempted once per channel change. Once a swap fails for a particular AP, it should not be attempted anytime soon. Thus, the information record that exists for each DFS-capable AP also includes a timer. The timer is used to allow swap requests for the same AP to be split into a certain number of times (ie, 24).
    [73] As described above, in channel selection of a wireless LAN communication network, there is a problem in that channel selection is not optimized for the entire network. Accordingly, the present invention allows the optimal channel selection by swapping channels between access points using a swapping mechanism, thereby improving overall performance of the WLAN communication network.
    权利要求:
    Claims (10)
    [1" claim-type="Currently amended] Observe the access point traffic load of the access point, send probe requests and probe responses to other access points, receive probe requests and probe responses from other access points, and on the traffic load at the probe responses Include information, compute and store interference parameters for each of the plurality of possible channels, calculate and store channel sharing parameters for each of the plurality of channels, and use the interference and channel sharing parameters, Compute a regular channel quality parameter (regCSIQ) for each of the plurality of channels indicative of interference and channel sharing in each of the plurality of channels, and using the regular channel quality parameters (regCSIQ), A wireless, configured to dynamically select an optimal channel from the possible channels As the access point (AP1, AP2, AP3) in a communication network,
    The access point is configured to select the optimal channel by swapping channels with another access point using a swapping mechanism.
    [2" claim-type="Currently amended] The method of claim 1, wherein the access point operates on a first channel C1 and calculates a swap specific channel quality parameter ssCSIQ for all response access points AP2 operating on a second channel C2. A swap request access point (AP1) to store, the swap specific channel quality parameter (ssCSIQ) is calculated under the assumption that all the response access point (AP2) and the request access point (AP1) has already swapped channels, the swap Specific channel quality parameters are used in the swapping mechanism.
    [3" claim-type="Currently amended] The method of claim 2, wherein the swapping mechanism,
    Computing a gain-in-performance parameter SwapBinP having a value equal to a difference between a lowest parameter of all regular channel quality parameters and a lowest parameter of all swap specific channel quality parameters;
    Transmitting a swap request including the performance gain parameter (SwapBinP) to another access point corresponding to the lowest parameter among all swap specific channel quality parameters of all the response access points (AP2);
    Waiting for a swap response from the other access point AP2;
    If the swap response is yes, switching to a channel corresponding to the lowest parameter of all swap specific channel quality parameters; And
    If the swap response is no, switching to the channel corresponding to the lowest parameter of all regular channel quality parameters.
    [4" claim-type="Currently amended] The method of claim 1, wherein the access point,
    Receiving a swap request from a swap request access point (AP1) operating on a first channel (C1), wherein the swap response access point is operated on a second channel (C2);
    Rescanning all its channels to collect probe responses from other access points;
    Switching the second channel (C2) to the first channel (C1);
    Calculating a swap specific channel quality parameter ssCSIQ (C1) for the first channel C1, wherein the swap specific channel quality parameter ssCSIQ (C1) is associated with the response access point AP2 and the swap; Computed on the assumption that the request access point AP1 has already swapped channels; And
    If the swap specific channel quality parameter (ssCSIQ (C1)) for the first channel (C1) is smaller than the regular channel quality parameter (regCSIQ (C2)) calculated for the second channel (C2) Yes Access point characterized in that the swap response access point (AP2) configured to perform the step of transmitting.
    [5" claim-type="Currently amended] The method of claim 4, wherein the access point,
    Benefit-in-performance from the swap request access point having a value equal to the difference between the lowest of all regular channel quality parameters and the lowest of all swap specific channel quality parameters for the swap request access point Receiving a parameter SwapBinP;
    If a swap response 'yes' cannot be sent, calculate a decrease-in-performance parameter indicating a decrease in performance of the swap response access point that occurs if the swap request access point has swapped channels. Steps; And
    And if the performance gain parameter (SwapBinP) is greater than the performance reduction parameter, sending a swap response 'yes'.
    [6" claim-type="Currently amended] 6. The access point according to claim 1, wherein the access point is configured to use the swapping mechanism only after a predetermined time has elapsed from the last time using the swapping mechanism.
    [7" claim-type="Currently amended] And at least two access points according to any one of the preceding claims.
    [8" claim-type="Currently amended] Observing the access point traffic load of the access point, sending probe requests and probe responses to other access points, receiving probe requests and probe responses from other access points, and the probe response Computing information on the traffic load, computing and storing interference parameters for each of the plurality of possible channels, computing and storing channel sharing parameters for each of the plurality of channels; Calculate, using the interference and channel sharing parameters, a regular channel quality parameter (regCSIQ) for each of the plurality of channels indicative of the amount of interference and channel sharing in each of the plurality of channels, and Use parameters (regCSIQ) to derive the optimal channel from multiple possible channels A method for selecting an optimal channel by an access point of a wireless LAN communication network comprising the step of selectively selecting,
    And wherein said access point is configured to select said optimal channel by mutually swapping channels with another access point using a swapping mechanism.
    [9" claim-type="Currently amended] Observe the access point traffic load of the access point, send probe requests and probe responses to other access points, receive probe requests and probe responses from other access points, and on the traffic load at the probe responses Include information, compute and store interference parameters for each of the plurality of possible channels, calculate and store channel sharing parameters for each of the plurality of channels, and use the interference and channel sharing parameters, Compute a regular channel quality parameter (regCSIQ) for each of the plurality of channels indicative of interference and channel sharing in each of the plurality of channels, and using the regular channel quality parameters (regCSIQ), Access point that dynamically selects the best channel from the available channels A computer program that is loaded by, the wireless LAN access point for the communication network that provides,
    The access point is configured to select the optimal channel by mutually swapping channels with another access point using a swapping mechanism.
    [10" claim-type="Currently amended] A data moving medium provided with a computer program according to claim 9.
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    同族专利:
    公开号 | 公开日
    US8150955B2|2012-04-03|
    EP1257092A1|2002-11-13|
    JP2003032268A|2003-01-31|
    EP1257092B1|2005-01-05|
    US20020176437A1|2002-11-28|
    DE60108225D1|2005-02-10|
    US7499964B2|2009-03-03|
    KR100881448B1|2009-02-06|
    JP4048817B2|2008-02-20|
    US20090092101A1|2009-04-09|
    DE60108225T2|2005-12-08|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2001-05-08|Priority to EP01304146.2
    2001-05-08|Priority to EP20010304146
    2002-05-08|Application filed by 에이저 시스템즈 가디언 코포레이션
    2002-11-16|Publication of KR20020085853A
    2009-02-06|Application granted
    2009-02-06|Publication of KR100881448B1
    优先权:
    申请号 | 申请日 | 专利标题
    EP01304146.2|2001-05-08|
    EP20010304146|EP1257092B1|2001-05-08|2001-05-08|Dynamic frequency selection in a wireless LAN with channel swapping between access points|
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