Patent Publication Number: US-2010111144-A1

Title: Method for determining and changing rf channel and rf transceiving system using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. § 119(a) to Patent Application No. 097142921 filed in Taiwan, R.O.C. on Nov. 6, 2008, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a radio frequency (RF) technology and, more particularly, to an RF channel determining and changing method and an RF transceiving system using the method capable of randomly and automatically generating a communication channel according to the communication status. 
     2. Description of the Prior Art 
     When there are many persons using wireless transmission devices at the same time in the same room, it is very likely to cause channel collision. With the advancement in technology, there are lots of computers, equipments, cables etc. in the daily life, which results in electromagnetic interference (EMI). Therefore, some channels may be mal-functional to cause interruption of data transmission or reception error when multiple wireless transmission devices are used. 
     To prevent errors in data transmission and reception due to signal interference, for example, Taiwan Patent Pub. No. I23264 discloses a uni-directional multi-frequency wireless semi-automatic frequency scanning remote device. The device is capable of channel scanning so that the user is able to select a channel at a transmitting end by triggering such mechanism to transmit data and test whether data is received at a receiving end by channel scanning to search the channel required at the transmitting end. If the receiving end fails to receive any data, the user has to re-trigger the channel scanning mechanism. The transmitting end transmits data through a next channel, and the receiving end re-scans the channels. 
     Moreover, U.S. Pub. No. 20040133921 discloses an RF output channel setting device, using manual setting to change the communication channel. When the user presses a certain button for several seconds according to practical demand, a corresponding channel is acquired at the transmitting end. Meanwhile, the updated channel is available at the receiving end by channel scanning to receive the signal from the transmitting end. 
     SUMMARY OF THE INVENTION 
     The present invention provides an RF channel determining and changing method with frequency-hopping to prevent data from being lost and special coding to prevent data from reception error. If the user wants to re-set the code and the channel, the random value selects the channel and prevents channel collision. When interference takes place to malfunction the channel (at the transmitting end, whether the data has been re-sent for times more than preset is examined; and at the receiving end, whether there is no data received for time longer than preset is examined), frequency-hopping automatically starts. Therefore, in the present invention, when the channel is interfered, frequency-hopping automatically starts to update the channel to ensure that the data in transceiving process will not be stopping, erroneous, or lost during the user operation. 
     The present invention further provides an RF transceiving system, in which a channel for communication between two wireless transmission modules is constructed automatically and randomly to prevent the communication channel from being duplicated so that channel collision is avoided. The wireless transmission module at the receiving end is further connected to an electronic device so that the wireless transmission module at the transmitting end communicates with the electronic device. 
     In one embodiment, the present invention provides an RF channel determining method, comprising steps of: generating a random value; determining an updated channel according to the random value; and setting a signal transmitting channel of an RF transmitting device as the updated channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and spirits of various embodiments of the present invention will be readily understood by the accompanying drawings and detailed descriptions, wherein: 
         FIG. 1A  is a flowchart of an RF channel determining method according to one embodiment of the present invention; 
         FIG. 1B  is a flowchart of steps for generating a random value; 
         FIG. 1C  is a flowchart of steps for determining an updated channel; 
         FIG. 1D  is a remainder-to-channel relation table; 
         FIG. 2  is a schematic diagram of an RF transceiving system according to one embodiment of the present invention; 
         FIG. 3A  to  FIG. 3C  are flowcharts of an RF channel changing method of the present invention; 
         FIG. 4A  and  FIG. 4B  are channel-to-identification-code relation tables of two different RF transmitting devices; and 
         FIG. 5  is a schematic diagram showing RF wireless data transmission of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention can be exemplified but not limited by the embodiments as described hereinafter. 
     Please refer to  FIG. 1A , which is a flowchart of an RF channel determining method according to one embodiment of the present invention. In the present embodiment, the method  2  comprises steps described hereinafter. First, in step  20 , a random value is generated. The random value can be generated by various approaches.  FIG. 1B  is a flowchart of steps for generating a random value according to the present invention. In step  201 , a random seed is determined. The random seed can be determined by using a voltage value in a power supply in a transmitting end (an RF transmitting device in the present embodiment) or a time signal generated by a timer. Then in step  202 , the random value is generated according to the random seed. 
     Returning to  FIG. 1A , after the random value is generated, an updated channel is determined according to the random value in step  21 . Please refer to  FIG. 1C , which is a flowchart of steps for determining an updated channel. In step  210 , a remainder-to-channel relation table is determined. The remainder-to-channel relation table is shown in  FIG. 1D . For example, there are 16 channels, as numbered 0 to 15, available for the RF transmitting device of the present invention. The remainder is determined according to the divisor. Since there are 16 available channels in the present embodiment, the divisor is 16 and the dividend is used as the random value. Moreover, to prevent data from reception error by other devices at the receiving end, the present invention further comprises an identification code corresponding to each channel, as shown in  FIG. 1D . As data is sent through a certain channel, the first byte in the transmitted data package is the data code. Therefore, when the data package is decoded, it is determined whether the decoded package is required at the receiving end according to the identification code. 
     Returning to  FIG. 1C , after the table is determined, the random value is divided by the number of available channels capable of being used by the RF transmitting device to acquire a remainder in step  211 . Finally, in step  212 , a channel is determined corresponding to the remainder according to the remainder-to-channel relation table. For example, the random value generated according to step  20  is 81, which results in a remainder of 1 as 81 is divided by 16. Meanwhile, the corresponding channel number (channel 1 in the present embodiment) and the identification code 0x0B for the channel can be obtained by the remainder of 1 according to the table in  FIG. 1D . Returning to  FIG. 1A , after the updated channel is determined, step  22  is preformed to set a signal transmitting channel of an RF transmitting device as the updated channel. 
     Please refer to  FIG. 2 , which is a schematic diagram of an RF transceiving system according to one embodiment of the present invention. The RF transceiving system  3  comprises an RF transmitting device  30  and an RF receiving device  31 . The RF transmitting device  30  is capable of transmitting RF signals to be received by the RF receiving device  31 . Generally, the RF transmitting device  30  is a wireless inertia-sensing mouse, wireless inertia control device or other using RF devices. The RF transmitting device  30  comprises a first RF module  301 , a first micro-controller  302 , a power supply  303  and a peripheral input device  304 . The first RF module  301  comprises a data antenna  3010  and at least one informing antenna(s)  3011 ,  3012 . Even though a plurality of informing antennas are shown in  FIG. 2 , the number can be one. The number can be determined according to practical demand. The data antenna  3010  corresponds to a communication channel. The data antenna  3010  transmits data signals through the communication channel. The informing antennas  3011  and  3012  correspond respectively to an informing channel. Each informing antenna  3011  and  3012  transmits an informing signal through the informing channel. 
     The first micro-controller  302  is electrically connected to the first RF module  301 . The first micro-controller  302  controls the first RF module  301  to issue signals. In the present embodiment, the first micro-controller  302  comprises a random value generator  3020  capable of generating a random value. The first processor  3021  is electrically connected to the random value generator  3020  and the first RF module  301 . The first processor  3021  is capable of automatically changing the channel according to the random value to generate an updated channel to replace the communication channel. In the present embodiment, the random value generator  3020  further comprises an analog-to-digital converter  3023  (ADC), which is electrically connected to the power supply  303 . The analog-to-digital converter  3023  is capable of acquiring an analog voltage value of the power supply  303  and converting the analog voltage value to a digital signal as a random seed, from which the random value generator  3020  is capable of generating the random value. Certainly, in another embodiment, the analog-to-digital converter  3023  is also capable of acquiring a signal from the timer  305  and converting the signal to a digital signal as a random seed, from which the random value generator  3020  is capable of generating the random value. The memory unit  3022  is a flash memory or a conventional memory (such as DRAM or SDRAM), but is not limited thereto. The memory unit  3022  is capable of recording the communication channel, informing channel and corresponding identification code (as shown in  FIG. 1D ) that the first RF module  301  requires when issuing signals. Moreover, the first micro-controller  302  is further coupled to a peripheral input device  304 , being a keyboard or a roller. 
     The RF receiving device  31  comprises a second RF module  311  and a second micro-controller  312 . The second RF module  311  comprises a data antenna  3110  and at least an informing antenna(s)  3111  and  3112 . Even though a plurality of informing antennas are shown in  FIG. 2 , the number can be one. 
     The data antenna  3110  corresponds to a communication channel. The data antennas  3110  and  3112  receive data signal transmitted from the RF transmitting device  30  through the communication channel. The informing antennas  3111  and  3112  correspond respectively to an informing channel. Each informing antenna  3111  and  3112  receives informing signal transmitted from the RF transmitting device  30  through the informing channel. The second micro-controller  312  comprises a second processor  3120  and a memory unit  3121 . The second processor  3120  is capable of performing operation on the signal received by the second RF module  311 . The memory unit  3121  is a flash memory or a conventional memory (such as DRAM or SDRAM), but is not limited thereto. The memory unit  3022  is capable of recording the communication channel, informing channel and corresponding identification code (as shown in  FIG. 1D ) that the first RF module  311  requires when receiving signals. The second micro-controller  312  further coupled to is further coupled to a peripheral input device  313 , being a keyboard or a roller. The RF receiving device  31  further comprises a interface  314  so as to be electrically connected to an external electronic device  32 . The electronic device  32  is a computer, a multi-media gamer or other electronic devices interactive with the user. 
     The RF channel changing method of the present invention is described hereinafter. Please refer to  FIG. 3A  to  FIG. 3C , which are flowcharts of an RF channel changing method of the present invention. The flowcharts in  FIG. 3A  to  FIG. 3C  are described with reference to the structure in  FIG. 2 .  FIG. 3A  is a flowchart showing the operation of the RF transmitting device  30  performed by the first processor  3021 , while  FIG. 3B  is a flowchart showing the operation of the RF receiving device  31  performed by the second processor  3120 . In  FIG. 3A  and  FIG. 3B , the method  4  starts with step  400 . The data antenna  3010  in the first RF module  301  uses the communication channel stored in the memory unit  3022  to issue signals. In step  500 , the second RF module  311  of the RF receiving device  31  uses the code and channel stored in the memory unit  3121  to receive the signals transmitted by the first RF module  301 . As the RF transceiving system  3  starts, the RF wireless transmitting and receiving devices  30  and  31  use the code and channel stored in the memory units  3022  and  3121 , respectively. Assuming that there is no interference during data transmission, the system  3  keeps using the identification code and channel stored in the memory unit. 
     After step  400 , step  401  is performed to determine whether the communication channel and identification code are to be updated. In step  401 , manual approaches are used to update the communication channel and identification code; otherwise, step  402  is performed to keep using the communication channel and identification code stored in the memory unit  3022 . Then, step  403  is performed to determine whether communication is interrupted. In step  403 , whether communication is interrupted is determined according to whether the second RF module  311  responds with a handshaking signal. Because when the second RF module  311  receives the signal, the first processor  3021  determines that the RF receiving device  31  is out of communication if there is no handshaking signal representing receipt responded. Certainly, determining communication interruption has been disclosed in various approaches and is not limited to the aforementioned examples. If there is no signal interruption, the method returning to step  402 . Meanwhile, the steps in the method  5  in  FIG. 3B  are repeated between step  501  and  502 . 
     Returning to  FIG. 3A , if there is signal interruption, step  404  is performed. According to the informing channel and the corresponding identification code used by the informing antenna  3011  stored in the memory unit  3022 , the informing antenna  3011  issues the informing signal informing channel changing. Meanwhile, referring to  FIG. 3B , in RF receiving device  31 , the first RF module  301  transmits the signal informing channel changing according to step  404 . Steps  503  and  504  in  FIG. 3B  are performed to determine that the informing signal transmitted by the informing antenna  3011  of the first RF module  301  is received. In step  505 , the corresponding informing antenna  3111  is used to respond with a handshaking signal (ACK) to the RF transmitting device  30 . 
     Returning to  FIG. 3A , after step  405  is performed to determine whether the response signal from the second RF module  311  is received, step  408  is performed to update the communication channel. On the contrary, if no response signal is received, it means that the informing channel used by the informing antenna  3011  cannot communicate with the second RF module  311 . Therefore, step  406  is performed to determine whether there is any other informing antenna in the first RF module  301 , because each informing antenna corresponds to one informing channel. In the present embodiment, since the informing antenna  3011  cannot communicate with the RF receiving device  31 , step  407  is performed to update the informing antenna  3012  to inform the RF receiving device  31  to change the communication channel when a second informing antenna  3012  is available. Certainly, if the response is not received from the RF receiving device, step  406  is performed to see if there is any available informing channel. If not, the method returns to step  402 . 
     Returning to step  408 , the communication channel is changed. Please refer to  FIG. 3C , which is a flowchart of an RF channel changing method of the present invention. First in step  4080 , the analog-to-digital converter  3023  (ADC) in the random value generator  3020  is turned on. Referring to  FIG. 2 , in step  4080 , the analog-to-digital converter  3020  acquires the voltage value of the power supply  303  in the RF transmitting device  30 . Then, step  4081  is performed to convert the analog voltage value to a digital voltage value to obtain a random seed (M) by using voltage instability. In step  4082 , a random value (R) is generated in a random function in the random value generator  3020 . Then in step  4083 , assuming the available channel is channel 0˜N, a remainder is acquired as the random value is divided by (N+1). In step  4084 , a channel value and identification code corresponding to the remainder are acquired according to the table in  FIG. 1D , wherein the channel value is an updated channel to be changed. 
     The new identification code is generated to prevent signal interference. To prevent RF receiving device  31  from receiving information from a non-corresponding channel, a specific code is provided on each data package transmitted by the RF transmitting device  30 . When the RF receiving device  31  receives the data, the identification code is compared. If the received identification code is not consistent with a pre-determined code, the received identification code is disregarded. If the identification code is correct, it will be stored. Referring to  FIG. 4A ,  FIG. 4B  and  FIG. 5 , wherein  FIG. 4A  and  FIG. 4B  are channel-to-identification-code relation tables of two different RF transmitting devices, and  FIG. 5  is a schematic diagram showing RF wireless data transmission of the present invention. It is found that the different channels correspond to different identification codes. In  FIG. 5 , the communication system of the present invention is used in computer control. The two different RF transmitting devices  30   a  and  30   b  are wireless inertia-sensing devices capable of communicating with the computer  32  using the RF receiving device  31 . Considering that the RF wireless identifying device  30   a  and the RF wireless identifying device  30   b  use channel 1 as the communication channel at the same time, since the identification codes are different (0x0B and 0x1B, respectively), data reception error will not happen even if the RF receiving device receives the signal from the RF wireless identifying device  30   b  when it is requested to receive the signal from the RF transmitting device  30   a  instead. 
     Returning to  FIG. 3A , after step  408  determines an updated channel and corresponding identification code, step  409  is further performed to check whether the channel is being used to prevent channel collision. In step  409 , the RF transmitting device  30  uses the updated channel as a receiving channel. If the first processor  3021  determines that the first RF module  301  has received data through the updated channel, it means that the updated channel is being used. Therefore, the method returns to step  408  to select a new updated channel. On the contrary, if the first processor  3021  determines that the first RF module  301  has not received any data, it means that the channel is free. Meanwhile, in step  410 , the informing antenna  3011  transmits an informing signal to inform the RF receiving device  31  with a channel changing signal. Returning to  FIG. 3B , after the RF receiving device  31  receives channel changing and identification code signals from the RF transmitting device  30  in step  506 , step  507  is performed to respond with a handshaking signal. In step  508 , the new channel and corresponding identification code are stored in the memory unit  3121  so that the second RF module  311  can access to the receiving new channel and corresponding identification code. 
     Returning to  FIG. 3A , after a response signal from the RF receiving device  31  is received in step  411 , step  412  is performed to store the updated channel and corresponding identification code in the memory unit  3022  to replace the original communication channel and identification code to be used by the RF transmitting device  30 . The process stated above is for channel changing when communication interrupted. Moreover, the user can decide to change the channel as well. Referring to  FIG. 3A , in step  401 , if the user wants to change the channel, step  404  is performed to start channel determining from step  404  to  412  as stated above, which is not repeated herein. 
     Accordingly, the present invention provides an RF channel determining and changing method and an RF transceiving system using the method with automatic frequency-hopping to prevent data from being lost and special coding to prevent data from reception error so as to ensure that the data in transceiving process will not be stopping, erroneous, or lost during the user operation. Therefore, the present invention is useful, novel and non-obvious. 
     Although this invention has been disclosed and illustrated with reference to particular embodiments, the principles involved are susceptible for use in numerous other embodiments that will be apparent to persons skilled in the art. This invention is, therefore, to be limited only as indicated by the scope of the appended claims.