Abstract:
The disadvantage of the conventional wireless LAN is that it cannot increase the transmission speed until the standard is revised. Even though a proprietary technology can be developed, it would be inconvenient for users because it lacks generality.  
     The wireless LAN card  10  containing two sets of physical layer circuits  20   a  and  20   b  corresponding to two sets of wireless LAN standards (IEEE 802.11a and IEEE 802.11b) is controlled by the CPU  12.  By using these two sets of wireless LAN standards, it is possible to increase the amount of data transmission per unit time while maintaining the standards. Moreover, it is also possible to realize high-speed data transmission easily by using more than two wireless LAN standards simultaneously in parallel.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a wireless LAN, a method for data transmission and reception through a wireless LAN, and a medium storing a program to control data transmission and reception.  
           [0003]    2. Description of the Prior Art  
           [0004]    The wireless LAN involves a variety of standards, including the one specifying transmission speeds. These standards are being continuously revised with the times to meet requirements for higher speeds.  
           [0005]    The revision of standards needs solutions of non-technical problems as well as technical problems. Technical capability alone does not realize a high-speed wireless LAN.  
           [0006]    The conventional wireless LAN of this type employs any one of several standards to perform data transmission and reception.  
           [0007]    The disadvantage of the conventional wireless LAN is that it cannot increase the transmission speed until the standard is revised. Even though a proprietary technology can be developed, it would be inconvenient for users because it lacks generality.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to provide a wireless LAN, a method for data transmission and reception through a wireless LAN, and a medium storing a program to control data transmission and reception, said wireless LAN being able to increase the transmission speed while keeping the generality without waiting the revision of standards.  
           [0009]    The present invention to achieve the above-mentioned object is directed to a wireless LAN which comprises a data transmitting and receiving means capable of transmitting and receiving data according to a plurality of wireless LAN standards, and a data transmission/reception controlling means which permits said data transmitting and receiving means to transmit and receive data by using a plurality of wireless LAN standards simultaneously in parallel.  
           [0010]    According to the present invention constituted as mentioned above, the data transmitting and receiving means is able to transmit and receive data according to a plurality of wireless LAN standards and the data transmission/reception controlling means permits the data transmitting and receiving means to transmit and receive data by using a plurality of wireless LAN standards simultaneously in parallel.  
           [0011]    In other words, the present invention is designed to substantially increase the speed of data transmission and reception by using the existing standards simultaneously in parallel without modifying them.  
           [0012]    As mentioned above, the present invention provides a wireless LAN which can increase the transmission speed while keeping the generality without waiting the revision of standards.  
           [0013]    The above-mentioned data to be transmitted and received may be composed of packets and the above-mentioned data transmission/reception controlling means may be constructed such that the number of packets to be transmitted is adjusted according to each of the wireless LAN standards.  
           [0014]    In the case constructed as mentioned above, the data to be transmitted and received is composed of packets and the above-mentioned data transmission/reception controlling means is constructed such that the number of packets to be transmitted is adjusted according to each of the wireless LAN standards.  
           [0015]    In other words, if there are different data amounts conforming to individual standards, it is possible to allocate an adequate data amount without allocating the same data amount indiscriminately to each standard. By adjusting the number of packets to be transmitted for each standard in this way, it is possible to allocate an optimum data amount conforming to the standard.  
           [0016]    In addition, the above-mentioned data transmission/reception controlling means may be composed of two means. The first means acquires the execution transmission speed for data transmission and reception according to individual standards among a plurality of wireless LAN standards. The second means adjusts the number of packets to be allocated to each standard in response to the execution speed acquired.  
           [0017]    In the above-mentioned construction, the number of packets to be transmitted is adjusted for each standard among a plurality of wireless LAN standards. Therefore, the means to acquire the execution transmission speed in the means to control the data transmission and reception acquires the execution speed of data transmission and reception for each standard among a plurality of wireless LAN standards, and the means to adjust the number of packets allocates the number of packets for each standard in response to the acquired execution speed.  
           [0018]    Since the number of packets is allocated for each standard in response to the execution speed in this way, high-speed efficient data transmission and reception become possible without waste waiting time.  
           [0019]    Incidentally, the above-mentioned means to acquire the execution transmission speed may be constructed such that it acquires the execution speed before the start of data transmission and reception.  
           [0020]    In the case of this construction, the means to acquire the execution transmission speed acquires the execution speed before the start of data transmission and reception.  
           [0021]    In other words, the wireless LAN involves two cases. In one case there exists a general procedure to acquire the execution speed as the preliminary process for data transmission and reception, and in the other case, such a general procedure does not exist. If such a procedure is available, the execution speed is acquired by means of it, and if such a procedure is not available, the execution speed is acquired by using dummy data transmission and reception.  
           [0022]    By acquiring the execution speed previously before the start of data transmission and reception as mentioned above, it is possible to make an optimal allocation at the start of data transmission and reception.  
           [0023]    Moreover, the means to acquire the execution transmission speed may be constructed such that it acquires the execution speed in accordance with the amount of data transmitted and received after the start of data transmission and reception.  
           [0024]    In the case of this construction, the means to acquire the execution transmission speed acquires the execution speed in accordance with the amount of data transmitted and received after the start of data transmission and reception.  
           [0025]    In other words, since the processing time and the amount of data processed are known after the start of data transmission and reception, it is possible to acquire the execution speed in accordance with them.  
           [0026]    In addition, since the execution speed is acquired in accordance with the amount of data transmitted and received after the start of data transmission and reception, it is possible to accomplish optimal transmission and reception in accordance with the execution speed on the real conditions. It is also acceptable as a matter of course to amend the execution speed acquired at the start of data transmission and reception in accordance with the execution speed after the start of data transmission and reception.  
           [0027]    In addition, the means to adjust the number of packets may be constructed such that the number packets is allocated in proportion to the execution speed for each standard.  
           [0028]    In the above-mentioned construction, the means to adjust the number of packets allocates the number of packets in proportion to the execution speed for each standard for the number of packets to be allocated when the execution speed is acquired.  
           [0029]    Since the number of packets is allocated in proportion to the execution speed in this manner, a smaller number of packets is allocated to the one which has a slow execution speed and a larger number of packets is allocated to the one which has a high execution speed. Thus it is possible to realize an optimal allocation.  
           [0030]    In addition, the means to adjust the number of packets may be constructed such that it is referenced each time packets are transmitted sequentially and a table to specify the standard for transmission is prepared by referencing.  
           [0031]    In the above-mentioned construction, the means to adjust the number of packets prepares a table which is referenced each time packets are transmitted sequentially. This table is so designed as to specify the standard to be transmitted when it is referenced each time packets are transmitted. If a procedure to prepare the table is implemented previously, no further procedure is necessary later to specify the standard to be allocated. Thus, it is possible to allocate packets simply by referencing the table, and this simplifies the processing.  
           [0032]    The technique of performing data transmission and reception by using a plurality of wireless LAN standards simultaneously in parallel is not always limited to tangible devices; but it is easily understood that it functions as a method. Therefore, the invention pertaining to Claim 8 provides a method for performing data transmission and reception by using a plurality of wireless LAN standards simultaneously in parallel in the case where it is possible to perform data transmission and reception in accordance with a plurality of wireless LAN standards.  
           [0033]    In other words, there is no difference in that it is not limited to tangible devices but it is also effective as a method.  
           [0034]    Incidentally, such a wireless LAN may exist alone or incorporated into a certain machine. The concept of the invention is not limited to them; but it covers a variety of embodiments. Therefore, it will include software as well as hardware depending on situations.  
           [0035]    In the case where the concept of the present invention is embodied in wireless LAN software, it naturally exists in a recoding medium storing such software and it is used in such a way.  
           [0036]    As an example, the invention pertaining to Claim 9 provides a medium storing a program to control data transmission and reception by computers capable of data transmission and reception in accordance with a plurality of wireless LAN standards. It realizes the function to perform data transmission and reception by using a plurality of wireless LAN standards simultaneously in parallel.  
           [0037]    Needless to say, the recording medium may be a magnetic recording medium or a magneto-optical recording medium or any one which would be developed in the future. It also includes primary and secondary duplicates in any form.  
           [0038]    In addition, the concept of the present invention may be realized partly in the form of software and partly in the form of hardware. Alternatively, it may exist in such a form that a portion is recorded on a recording medium and read time to time as occasion demands.  
           [0039]    In the case where the present invention is embodied in software, it is possible to use hardware and operating system in combination or separately. For example, it is possible to accomplish arithmetic processes by calling a specific function from the operating system or entering such a function through the hardware instead of calling. Even though the present invention is practically embodied in the presence of operating system, it is to be understood that the present invention can be practiced only by this program in an environment in which the program is circulated in the form recorded in a medium.  
           [0040]    Moreover, in the case where the present invention is put into practice in the form of software, the invention is naturally realized as a medium which stores the program and also as the program itself. Thus the program itself is covered by the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0041]    [0041]FIG. 1 is a block diagram of the wireless LAN pertaining to one embodiment of the present invention.  
         [0042]    [0042]FIG. 2 is a block diagram of the wireless LAN pertaining to one modified embodiment of the present invention.  
         [0043]    [0043]FIG. 3 is a block diagram of the wireless LAN pertaining to another modified embodiment of the present invention.  
         [0044]    [0044]FIG. 4 is a block diagram of the wireless LAN pertaining to another modified embodiment of the present invention.  
         [0045]    [0045]FIG. 5 is a diagram showing the flowchart of main.  
         [0046]    [0046]FIG. 6 is a diagram which shows the correspondence between the sequence of packets and the standard to be used.  
         [0047]    [0047]FIG. 7 is a flowchart for table preparation.  
         [0048]    [0048]FIG. 8 is a flowchart for communications to be carried out by using the table.  
         [0049]    [0049]FIG. 9 is a flowchart for communications to be carried out by using the execution transmission speed based on the amount of actual data transmission. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]    The embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0051]    (1) The First Embodiment:  
         [0052]    [0052]FIG. 1 is a schematic block diagram showing the structure of hardware for the wireless LAN card which realizes the wireless LAN pertaining to the first embodiment of the present invention.  
         [0053]    In this figure, the wireless LAN card  10  has the bus IF  11  which is an interface for connection to the bus to which are attached computer peripherals (not shown), and it is also connected to the CPU  12  for its centralized control. The CPU  12  is connected to the internal bus  13 , to which are connected the RAM  14  and the ROM  15 . The CPU  12  executes arithmetic processing by using the storage area in the RAM  14  in accordance with the firmware and data stored in the ROM  15 .  
         [0054]    The bus  13  has two sets of physical layer circuits  20  connected thereto. Each of the physical layer circuits  20  consists of the MAC circuit  21 , the baseband processor (BBP) circuit  22 , and the radio circuit (RF)  23 . The MAC circuit  21  controls medium access, and the radio circuit  23  transmits digital data over an appropriate frequency band, with the baseband processor circuit  22  interposed.  
         [0055]    In this embodiment, the first physical layer circuit  20   a  realizes the wireless LAN conforming to the standard of IEEE 802.11a. It uses the frequency band of 2.4 GHz. On the other hand, the second physical layer circuit  20   b  realizes the wireless LAN conforming to the standard of IEEE 802.11b. It uses the frequency band of 5 GHz.  
         [0056]    In this embodiment, the physical layer circuits  20   a  and  20   b  are separately constructed; however, it is possible to construct them such that part of the hardware is possessed in common. For example, in the embodiment shown in FIG. 2, the two baseband processor circuits  22  are replaced by a single baseband processor circuit  24  which is possessed in common. The embodiment shown in FIG. 3 has a single baseband processor  25  possessed in common and also has the radio circuit  28  (capable of broad band amplification) which handles both 2.4 GHz band and 5 GHz band. The band pass filters  27  and  28  facilitate the signal processing for components only in the frequency bands of 2.4 GHz and 5 GHz.  
         [0057]    For easy understanding, the foregoing embodiments were explained on the assumption that two standards are used simultaneously in parallel. However, the present invention is not restricted to the case where two standards are used. FIG. 4 is a schematic block diagram showing the hardware construction corresponding to as many wireless LAN standards as n. It is to be noted that n sets of physical layer circuits  20  are connected in parallel to the bus  13 .  
         [0058]    The following explains the case in which as many standards as n are used simultaneously in parallel.  
         [0059]    [0059]FIG. 5 is a schematic flowchart for network connection and data transmission through the wireless LAN card  10  pertaining to the present invention. Incidentally, data transmission through LAN usually needs two sets of flow for the transmission side Tx and the reception side Rx. However, the following description is restricted to one procedure alone for easy understanding.  
         [0060]    The step  100  is intended for measurement of execution (or substantial) transmission speed bw. The execution transmission speed is measured at the start of session. In other words, the execution transmission speed bw per unit time is measured on the basis of time required to confirm that all data have been transmitted normally (time difference between start and completion of transmission) and also on the basis of the substantial amount of data transmitted when a certain amount of data is transmitted from the transmission side Tx to the reception side Rx.  
         [0061]    The execution transmission speeds bw measured in this manner are designated as bw1 and bw2 for the physical layer circuits  20   a  and  20   b  corresponding to two standards (IEEE802.11a and IEEE802.11b). Also, they are designated as bw1 to bwn if there are n standards.  
         [0062]    The step  200  is intended to prepare, based on the result of measurement, the table to specify the sequence of sending packets and the standard to be used.  
         [0063]    [0063]FIG. 6 is a table which shows the correspondence between the packet sending sequence and the standard to be used. This table is prepared in a way which is explained below with reference to the flowchart shown in FIG. 7. The step  405  is intended to obtain an approximate integer ratio on the basis of the execution transmission speed for each standard and then obtain its total. For example, assuming that the ratio of the execution transmission speed is 2:2:1 for standards (1) to (3), the total is 5.  
         [0064]    Next, the step  410  is intended to prepare a table having as many elements as the total. In this example, a table having 5 elements is prepared as shown in FIG. 6. The step  415  is intended to fill the table in such a way that the standards are evenly distributed. For example, if the total of elements is 5 and the standard (1) has an integer ratio of 2, 2 is divided by 5 and the result (2/5=2.5) is rounded up to 3. Thus the elements are separated by 3. Consequently, the standard (1) is applied to the first and fourth elements in the table. Likewise, in the case of the standard (2) in which the integer ratio is 2, the table is filled with elements which are apart at intervals of 3 so that elements are scattered evenly. However, since there are empty boxes, the elements are moved down sequentially so that the second and fifth elements conform to the standard (2).  
         [0065]    As for the standard (3), only the third box is empty for the element. Therefore, the third element in the table is regarded as conforming to the standard (2). The above-mentioned algorism is a mere example for even distribution; it would be possible to adopt another algorism for more efficient distribution.  
         [0066]    Next, how to perform communications by referencing this table is explained below with reference to the flowchart shown in FIG. 8.  
         [0067]    Step  505  is to clear the number Ip of packets as in the previous case. Step  510  is to increment the number Ip of packets by 1. Step  515  is to reference the table based on the number of packets Ip counted. The number Ip of packets is divided by the number of elements and the remainder is obtained. For example, assuming that the number of elements in the table is 5, the remainder of division is 1 if the number Ip of packets is 1 or 6. As the result of referencing the table, packets are transmitted in accordance with the standard (1) in step  520 .  
         [0068]    Step  525  is to judge whether or not the transmission of packets has completed; and if not, step  510  and onward are repeated.  
         [0069]    (2) The Second Embodiment  
         [0070]    In the above-mentioned embodiment, the execution transmission speed is based on the value measured before the start of data transmission and reception. However, there is the possibility that a discrepancy occurs between the execution transmission speed obtained in a short period and the execution transmission speed based on the result of data transmission over a long period of time. Thus, how to measure the execution transmission speed based on the amount of actual data transmission is explained below with reference to the flowchart shown in FIG. 9.  
         [0071]    First, step  605  is to set the present time at a variable T1. Step  610  is to clear the total number TIp of packets. Step  615  is to clear the number Ip of packets. It is assumed in the following that the elapsed time is measured at the time when as many packets as the total number TIp of packets have been transmitted, and the execution transmission speed per unit time is obtained.  
         [0072]    First, step  620  is to increment the total number TIp of packets by 1. Step  625  is to judge whether or not the total number TIp of packets exceeds the prescribed number Tn. If the total number TIp of packets exceeds the prescribed number Tn, step  630  sets the present time to T2, and step  635  measures the execution speed for each standard. The amount of data transmission for each standard may be actually counted or determined by using the ratio for each standard mentioned in the table if the table has been prepared. Step  640  is to prepare the table again in the same way as shown in FIG. 8 on the basis of the actual transmission speed.  
         [0073]    After that, step  645  sets again the present time to T1, and step  650  clears the total number TIp of packets.  
         [0074]    Steps  655  to  670  are intended to perform processing to obtain the standard to be used by referencing the table. This processing is performed in the same way as in the flowchart shown in FIG. 8.  
         [0075]    Incidentally, step  665  performs the packet transmission in accordance with the standard referenced in the table. Alternatively, the execution speed may be obtained by measuring time required for packet transmission, accumulating sequentially transmission time for individual standards, and multiplying the accumulated time by the number of packets transmitted.  
         [0076]    As mentioned above, the wireless LAN card  10  containing two sets of physical layer circuits  20   a  and  20   b  corresponding to two sets of wireless LAN standards (IEEE 802.11a and IEEE 802.11b) is controlled by the CPU  12 . By using these two sets of wireless LAN standards, it is possible to increase the amount of data transmission per unit time while maintaining the standards. Moreover, it is also possible to realize high-speed data transmission easily by using more than two wireless LAN standards simultaneously in parallel.