Abstract:
A Wireless Distribution System (WDS) repeater in a Wireless Local Area Network (WLAN), the WDS repeater includes: a controller adapted to compare a wireless link rate of a WLAN signal received from an Access Point (AP) of the WLAN to a wireless link rate threshold registered in a wireless link rate table, and to display a connectability status of the wireless link according to the comparison result. A method of displaying a WDS link status in a wireless LAN system includes: detecting a wireless link rate of a WLAN signal received from an AP; comparing the detected wireless link rate to a wireless link rate threshold registered in a wireless link rate table; and displaying an ability to establish a connection when the detected wireless link rate is equal to or greater than the wireless link rate threshold.

Description:
CLAIM OF PRIORITY  
       [0001]     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from an application for WIRELESS DISTRIBUTION SYSTEM REPEATER IN WIRELESS LAN SYSTEM AND METHOD OF CONTROLLING THE SAME filed in the Korean Intellectual Property Office on 11 Jul. 2005 and there duly assigned Serial No. 10-2005-0062438.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a Wireless Distribution System (WDS) repeater in a Wireless Local Area Network (LAN) and its control method.  
         [0004]     2. Description of the Related Art  
         [0005]     Information terminals such as a Personal Computer (PC), a laptop computer, and a Personal Digital Assistant (PDA) use a network called a Local Area Network (LAN) to share information with each other. LANs are classified into a wire LAN which connects information terminals through a communication cable and a Wireless LAN (WLAN) of a wireless communication method which employs Access Points (APs).  
         [0006]     Of these, the WLAN performs wireless communication using a radio frequency or light for data transmission, and thus is convenient to move, extend, and maintain. The WLAN provides a 10/100 base-T Ethernet interface function of IEEE 802.3 as a wire processing unit and provides a transmission rate of 2 Mbps in a frequency band of 2.4 GHz of IEEE 802.11 as a wireless processing unit.  
         [0007]     Since October, 1990, an IEEE 802.11 committee has been working on internationally standardizing the WLAN according to an Open System Interconnection (OSI) reference model for wireless Medium Access Control (MAC) and physical layer specifications. IEEE 802.11 follows “Standard for Information Technology-Telecommunications and Information Exchange between Systems-Local and Metropolitan Area Networks-Specific Requirements-Part ?: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications”, 1999 edition, as a WLAN standard which is now in widespread use.  
         [0008]     While standardization of the WLAN is still progressing, there is a trend of several physical layer specifications sharing one MAC protocol. As basic transmission technology, InfraRed (IR) communication and Radio Frequency (RF) communication are under discussion. The RF communication method employs a spread spectrum method which spreads data over a wide frequency band to perform data transmission with no interference.  
         [0009]     The typical WLAN comprises a WLAN terminal used as an information terminal used by a user, an Access Point (AP) which is arranged between the WLAN terminal and a hub and transmits a communication network request from the WLAN terminal to an authentication server to repeat WLAN communication of a corresponding WLAN terminal, a router and a hub which access the communication network, and an authentication server which provides a communication access service. The typical WLAN further comprises a repeater which performs the same function as the AP to enhance the capability of the WLAN. The repeater uses a Wireless Distribution System (WDS) function which makes up a wireless network between the APs. If an AP that is not connected to the communication network is connected to an AP that is connected to the communication network through the WDS function, WLAN terminals can use the communication network by accessing the non-connected AP. That is, the WDS function serves as a bridge/repeater that extends an available wireless communication range.  
         [0010]     The WLAN system based on IEEE 802.11 MAC and IEEE 802.11 a/b/g PHY is widely used in homes and offices, as many users have purchased and installed an AP or a repeater.  
         [0011]     However, since a manual for the AP or repeater does not describe installation, the user first installs the AP or repeater in a desired region, and if it does not work, moves it closer to a main AP and installs it again. Thus, installation of the AP or repeater is difficult.  
         [0012]     In addition, even when the AP or repeater is moved closer to the main AP, the user has no way of knowing whether or not it is within working range.  
         [0013]     Furthermore, since the conventional WLAN system is provided to users at a low cost, most users do not have a high-priced radiolocator. Thus, the WLAN system can only be accurately installed by an installation technician having a radiolocator (e.g., yellow jacket).  
       SUMMARY OF THE INVENTION  
       [0014]     It is, therefore an object of the present invention to provide a WDS repeater in a WLAN which indicates setting information, such as an optimum setting distance between a main AP and a repeater and a transmission rate, for a user&#39;s reference when connecting the AP and the repeater to install the-WLAN, and its control method.  
         [0015]     According to one aspect of the present invention, a Wireless Distribution System (WDS) repeater in a Wireless Local Area Network (WLAN) is provided, the WDS repeater including: a controller adapted to compare a wireless link rate of a WLAN signal received from an Access Point (AP) of the WLAN to a wireless link rate threshold registered in a wireless link rate table, and to display a connectability status of the wireless link according to the comparison result.  
         [0016]     The controller preferably includes: a detector adapted to detect the wireless link rate of the WLAN signal received from the AP; a comparator adapted to compare the wireless link rate detected by the detector to the wireless link rate threshold registered in the wireless link table; and a display adapted to display the connectability status according to the comparison result. The controller preferably further includes: a setter adapted to change or set the wireless link rate threshold registered in the wireless link table according a data transmission rate of the WLAN signal. The controller is preferably adapted to detect the wireless link rate using one of a Communication Quality (CQ) level, a Received Signal Strength Indicator (RSSI) level, or a ping delay.  
         [0017]     The wireless link rate table preferably includes transmission rates of the WLAN signal and at least one wireless link rate threshold depending on the transmission rate of the WLAN signal according to a draft WLAN standard.  
         [0018]     The display preferably includes at least one LED or alarm adapted to indicate the connectability status of a wireless link to another AP.  
         [0019]     According to another aspect of the present invention, a method of displaying a Wireless Distribution System (WDS) link status in a Wireless Local Area Network (WLAN) is provided, the method including: detecting a wireless link rate of a WLAN signal received from an Access Point (AP); comparing the detected wireless link rate to a wireless link rate threshold registered in a wireless link rate table; and displaying an ability to establish a connection when the detected wireless link rate is equal to or greater than the wireless link rate threshold.  
         [0020]     The method preferably further includes displaying an inability to establish a connection when the detected wireless link rate is smaller than the threshold of the previously set wireless link rate.  
         [0021]     The method preferably further includes changing or setting the wireless link rate threshold registered in the wireless link rate table according to a data transmission rate of the WLAN signal.  
         [0022]     The wireless link rate is preferably detected using one of a Communication Quality (CQ) level, a Received Signal Strength Indicator (RSSI) level, or a ping delay.  
         [0023]     In comparing the detected wireless link rate to a wireless link rate threshold registered in a wireless link rate table, the wireless link rate table preferably includes transmission rates of the WLAN signal and at least one wireless link rate threshold depending on a transmission rate of the WLAN signal according to a draft WLAN standard.  
         [0024]     According to still another aspect of the present invention, a Wireless Local Area Network (WLAN) is provided including: a repeater adapted to compare a wireless link rate of a WLAN signal received from an Access Point (AP) to a wireless link rate threshold registered in a wireless link rate table and to display a connectability status of the wireless link according to the comparison result.  
         [0025]     The repeater preferably includes: a detector adapted to detect the wireless link rate of the WLAN signal received from the AP; a comparator adapted to compare the wireless link rate detected by the detector to the wireless link rate threshold registered in the wireless link table; and a display adapted to display the connectability status according to the comparison result. The repeater preferably further includes: a setter adapted to change or set the wireless link rate threshold registered in the wireless link table according a data transmission rate of the WLAN signal. The repeater is preferably adapted to detect the wireless link rate using one of a Communication Quality (CQ) level, a Received Signal Strength Indicator (RS SI) level, or a ping delay.  
         [0026]     The wireless link rate table preferably includes transmission rates of the WLAN signal and at least one wireless link rate threshold depending on the transmission rate of the WLAN signal according to a draft WLAN standard.  
         [0027]     The display preferably includes at least one LED or alarm adapted to indicate the connectability status of a wireless link to another AP.  
         [0028]     According to yet another aspect of the present invention, a Wireless Local Area Network (WLAN) is provided including: an Access Point (AP) adapted to receive a WLAN signal from a repeater; to compare a wireless link rate of the received WLAN signal from a repeater to a wireless link rate threshold registered in a wireless link rate table; and to display a connectability status of the wireless link according to the comparison result.  
         [0029]     The AP preferably includes: a detector adapted to detect the wireless link rate of the received WLAN signal from the repeater; a comparator adapted to compare the wireless link rate detected by the detector to the wireless link rate threshold registered in the wireless link table; and a display adapted to display the connectability status according to the comparison result. The AP preferably further includes: a setter adapted to change or set the wireless link rate threshold registered in the wireless link table according a data transmission rate of the WLAN signal. The AP is preferably adapted to detect the wireless link rate using one of a Communication Quality (CQ) level, a Received Signal Strength Indicator (RSSI) level, or a ping delay.  
         [0030]     The wireless link rate table preferably includes transmission rates of the WLAN signal and at least one wireless link rate threshold depending on the transmission rate of the WLAN signal according to a draft WLAN standard.  
         [0031]     The display preferably includes at least one LED or alarm adapted to indicate a connectability status of a wireless link to another AP. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]     A more complete appreciation of the present invention, and many of the attendant advantages thereof, will be readily apparent as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which like reference symbols indicate the same or similar components, wherein:  
         [0033]      FIG. 1  is a schematic diagram of a WLAN system according to the present invention;  
         [0034]      FIG. 2  is a block diagram of a repeater of the WLAN system according to an exemplary embodiment of the present invention;  
         [0035]      FIG. 3  is a block diagram of an Access Point (AP) in the WLAN system according to another exemplary embodiment of the present invention; and  
         [0036]      FIG. 4  is a flowchart illustrating a method of displaying a WDS link status in the WLAN system according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]      FIG. 1  is a schematic diagram of a WLAN system according to the present invention. The WLAN system of  FIG. 1  comprises an AP  10 , a repeater  20 , and a WLAN terminal  30 . With regard to the repeater  20 , since the AP  10  has a repeater function, an AP  10  that functions to relay a WLAN signal is referred to as a repeater.  
         [0038]     The AP  10  compares a wireless link rate of a received WLAN signal from the repeater  20  or the WLAN terminal  30  to a wireless link rate threshold registered in a link rate table and indicates a connectability status of a corresponding wireless link according to the comparison result. The wireless link rate of the WLAN signal is detected by using a Communication Quality (CQ) level, a Received Signal Strength Indicator (RSSI) level, or a ping delay. The CQ level is usually used as an index for performing a handoff in a mobile communication system, and the AP  10  can easily obtain the CQ information through, for example, a task for receiving the WLAN signal.  
         [0039]     The connectability status of the link is indicated to a user through the following processed task:  
                                                    /*Example Function */            void detect_link_status( )            { .... /* conditions of 802.11b and 802.11g are first clicked here           to carry out conditions of a corresponding access environment */            if(cq_rate &gt;= 80) { /* LED stays turned on*/ }            .....            else if(cq &lt; 30) { /* LED is flickers at an interval of one second           or various alarms are indicated*/ }            }                      
 
         [0040]     The repeater  20  compares a wireless link rate of a WLAN signal received from the AP  10  to a wireless link rate threshold registered in a link rate table and indicates a connectability status of a corresponding wireless link according to the comparison result.  
         [0041]     General functions and operation details of each of the components of  FIG. 1  have not been described in detail here. Only the specific operation the components in the present invention have been described.  
         [0042]      FIG. 2  is a block diagram of the repeater of the WLAN system according to an exemplary embodiment of the present invention.  
         [0043]     The repeater  20  comprises a controller  11 , which has a detector  100 , a comparator  200 , a display  300 , and a setter  400 , and a transceiver  12 . The transceiver  12  functions to transmit/receive the WLAN signal to/from another AP  10  or the WLAN terminal  30 .  
         [0044]     The detector  100  detects the wireless link rate of the WLAN signal received from the AP  10  or the WLAN terminal  30 . The wireless link rate of the WLAN signal detected by the detector  100  is detected by using the CQ level, the RSSI level, or the ping delay. The CQ level is usually used as an index for performing a handoff in a mobile communication system.  
         [0045]     The comparator  200  compares the wireless link rate detected by the detector  100  to the wireless link rate threshold registered in a link rate table such as Table 1:  
                                                 TABLE 1                       WDS link rate   802.11b   802.11g   Remarks                                ≧54   Mbps   No relevant data   ≧80   Data are averages of       ≧27   Mbps   No relevant data   ≧60   values obtained by       ≧11   Mbps   ≧80   ≧50   self-testing       ≧5.5   Mbps   ≧60   ≧40       ≧2   Mbps   ≧30   ≧30                  
 
         [0046]     Table 1 shows wireless link rates of the draft standards 802.11b and 802.11g, and a standard value of the wireless link rate is obtained by converting the CQ level into  100 .  
         [0047]     The display  300  indicates the connectability status of the corresponding wireless link to the user according to the comparison result of the comparator  200 . The display  300  can inform the user of the connectability status visually or aurally by using an LED or alarm, and indicates the changing transmission rate which changes according to position.  
         [0048]     The setter  400  changes a wireless link rate threshold previously set in the comparator  200 . That is, the wireless link rate threshold is set so that the AP  100  and the repeater  20  can access each other at the user&#39;s desired transmission rate. For example, if the user desires to set a transmission rate of at least 27 Mbps between the AP  10  and the repeater  20 , it can be performed by changing the wireless link rate threshold to at least 60% through the setter  400 . The transmission rate cannot be set to at least 27 Mbps in the draft standard 802.11b, and the transmission rate can be set to at least 54 Mbps, 27 Mbps, 11 Mbps, 5.5 Mbps, and 2 Mbps according to the wireless link rate threshold in the draft standard 802.11 g.  
         [0049]     A procedure for the user to install the repeater  20  according to the draft standard 802.11b in the AP  10  in the WLAN system having the above-described configuration is explained below.  
         [0050]     First, the user operates the fixed AP  10  which is connected to the router  1  or the server  2 , so that the AP  10  has a Basic Service Set (BSS) region which the repeater  20  or the WLAN terminal  30  can access.  
         [0051]     Then, the user operates the repeater  20  which is to access the AP  10 .  
         [0052]     The detector  100  of the repeater  20  detects the wireless link rate of the WLAN signal received through the AP  10 . The detector  100  detects the wireless link rate of the WLAN signal by using the CQ level, the RSSI level, or the ping delay.  
         [0053]     Next, the comparator  200  of the repeater  20  compares the wireless link rate (e.g., 20%) detected through the detector  100  to the previously set wireless link rate (e.g., 30%). If the repeater  20  is not located within the BSS region of the AP  10  or is far from the AP  10 , the detected wireless link rate (20%) is lower than the previously set wireless link rate (30%), so that the display  300  informs the user of the inability to establish a connection. The display  300  can employ an LED or an alarm.  
         [0054]     After the above operation, the detector  100  continually detects the wireless link rate of the WLAN signal received through the AP  100 , and the comparator  200  and the display  300  repetitively perform the above-described operation.  
         [0055]     Thereafter, while the user is moving the repeater  20  toward the AP  10 , the display  300  indicates the ability to establish a connection when the wireless link rate detected by the detector  100  is greater than the wireless link rate threshold registered in the wireless link rate table. For example, the LED device stays turned on, and a flicker interval of the LED changes in proportion to the transmission rate (e.g., 1 second for 54 Mbps, 2 seconds for 27 Mbps, 3 seconds for 11 Mbps, 4 seconds for 5.5 Mbps, and 5 seconds for 2 Mbps), so that the user can be aware of the transmission rate of the current position through the flickering interval.  
         [0056]     As a result, the user connects the repeater  20  to the AP  10  at a position where the display  300  indicates that it&#39;s possible to establish a connection.  
         [0057]     Accordingly, the user can be instantly aware of the connectability status of the wireless link through operation of the display  300  of the repeater  20  as the repeater  20  is moved.  
         [0058]      FIG. 3  is a block diagram of the AP  10  in the WLAN system according to another exemplary embodiment of the present invention.  
         [0059]     The AP  10  comprises a controller  11 , which has a detector  100 , a comparator  200 , a display  300 , and a setter  400 , and a transceiver  12 . The transceiver  12  functions to transmit/receive the WLAN signal to/from another the repeater  20  or the WLAN terminal  30 .  
         [0060]     The detector  100  detects the wireless link rate of the WLAN signal received from the repeater  20  or the WLAN terminal  30 .  
         [0061]     The comparator  200  compares the wireless link rate detected by the detector  100  to the threshold of the previously set wireless link rate.  
         [0062]     The display  300  indicates the connectability status of the corresponding wireless link according to the comparison result of the comparator  200  using an LED or alarm.  
         [0063]     A procedure for a user to install the AP  10  and the repeater  20  in the WLAN system having the above-described configuration is explained below.  
         [0064]     First, the user operates the fixed AP  10  which is connected to the router  1  or the server  2 , so that the AP  10  has a BSS region which the AP  10  or the WLAN terminal  30  can access.  
         [0065]     Then, another user operates the repeater  20  or the WLAN terminal  30  which is to access the AP  10  at a certain position.  
         [0066]     The detector  100  of the AP  10  detects the wireless link rate of the WLAN signal received through the repeater  20  or the WLAN terminal  30 . The detector  100  detects the wireless link rate of the WLAN signal by using the CQ level, the RSSI level, or the ping delay.  
         [0067]     Next, the comparator  200  of the repeater  20  compares the wireless link rate detected through the detector  100  to the previously set wireless link rate. If the repeater  20  or the WLAN terminal  30  is not located within the BSS region, the detected wireless link rate is lower than the previously set wireless link rate, so that the display  300  indicates to the user the inability to establish a connection.  
         [0068]     After the above operation, the detector  100  continually detects the wireless link rate of the WLAN signal received through the repeater  20  or the WLAN terminal  30 , and the comparator  200  and the display  300  perform the above-described operations.  
         [0069]     Thereafter, while the other user is moving the repeater  20  toward the AP  10 , the display  300  indicates the ability to establish a connection when the wireless link rate detected by the detector  100  is greater than the threshold (e.g., 30%) of the wireless link rate registered in the wireless link rate table. For example, the LED device stays turned on, and a flicker interval of the LED varies according to the transmission rate (e.g., 1 second for 54 Mbps, 2 seconds for 27 Mbps, 3 seconds for 11 Mbps, 4 seconds for 5.5 Mbps, and 5 seconds for 2 Mbps), so that the user can be aware of the transmission rate at the current position through the flickering interval.  
         [0070]     As a result, the user connects the repeater  20  to the AP  10  at the position where the display  300  indicates that a connection can be established.  
         [0071]     Accordingly, the user can instantly be aware of the connectability status of the wireless link through operation of the display  300  of the AP  10  while the other user moves the repeater  20 .  
         [0072]     Since at least one repeater can be connected to the AP, at least one display  300  can be provided.  
         [0073]     A method of controlling a WDS wireless link status in the WLAN system according to the present invention is explained below with reference to  FIG. 4 .  
         [0074]     First, the wireless link rate of the received WLAN signal is detected (step SI).  
         [0075]     Then, the detected wireless link rate is compared to the previously set wireless link rate (step S 2 ).  
         [0076]     Next, when it has been determined in step S 2  that the detected wireless link rate is equal to or greater than the threshold of the previously set wireless link rate, an ability to establish a connection is indicated to the user (step S 3 ).  
         [0077]     On the other hand, when it has been determined in step S 2  that the detected wireless link rate is smaller than the threshold of the previously set wireless link rate, an inability to establish a connection is indicated to the user (step S 4 ).  
         [0078]     Finally, the wireless link rate threshold registered in the wireless link rate table is changed or set according to the data transmission rate of the WLAN signal.  
         [0079]     As described above, according to the WLAN and its control method, since installation information such as the setting distance and the transmission rate is indicated to the user, it is easy to install the WLAN.  
         [0080]     While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various modifications in form and detail can be made therein without departing from the scope of the present invention as defined by the following claims.