Patent Publication Number: US-2003237037-A1

Title: Determination of signal transmission accuracy of a wireless device

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Technical Field  
       [0002] The present invention relates to a method and system for determining the transmission accuracy of a test signal transmitted to a remote device by a wireless transmitting device.  
       [0003] 2. Related Art  
       [0004] When a first person using a Walkie-Talkie talks to a second person also using a Walkie-Talkie, the first person does not know how accurate the transmission is from the Walkie-Talkie of the first person to the Walkie-Talkie of the second person. Thus, there is a need for a method and system for overcoming the lack of knowledge by the first person as to how accurate the transmission is from the Walkie-Talkie of the first person to the Walkie-Talkie of the second person.  
       Summary of the Invention  
       [0005] In first embodiments, the present invention provides a method for ascertaining the accuracy of transmission of a test signal, comprising:  
       [0006] transmitting by a first transceiver device the test signal to a second transceiver device, wherein the first transceiver device is wireless; and  
       [0007] receiving by the first transceiver device a return signal from the second transceiver device, wherein the return signal is the test signal as retransmitted by the second transceiver device to the first transceiver device after having been received by the second transceiver device, and wherein the receipt and retransmission of the test signal by the second transceiver device is accomplished without manual intervention by a user of the second transceiver device.  
       [0008] In second embodiments, the present invention provides a method for retransmitting a test signal, comprising:  
       [0009] receiving by a second transceiver device the test signal that had been transmitted to the second transceiver device by a first transceiver device, wherein the first transceiver device is wireless; and  
       [0010] retransmitting by the second transceiver device the test signal to the first transceiver device without manual intervention by a user of the second transceiver device.  
       [0011] In third embodiments, the present invention provides a system for ascertaining the accuracy of transmission of a test signal, comprising a first transceiver device, wherein the first transceiver device is wireless, and wherein the first transceiver device is adapted to:  
       [0012] transmit the test signal to a second transceiver device; and  
       [0013] receive a return signal from the second transceiver device, wherein the return signal is the test signal as retransmitted by the second transceiver device to the first transceiver device after having been received by the second transceiver device, and wherein the receipt and retransmission of the test signal by the second transceiver device is accomplished without manual intervention by a user of the second transceiver device.  
       [0014] In fourth embodiments, the present invention provides a system for retransmitting a test signal, comprising a second transceiver device adapted to:  
       [0015] receive the test signal transmitted to the second transceiver device by a first transceiver device, wherein the first transceiver device is wireless; and  
       [0016] retransmit the test signal to the first transceiver device without manual intervention by a user of the second transceiver device.  
       [0017] The present invention provides a method and system for overcoming the lack of knowledge by a first person as to how accurate transmission is from a Walkie-Talkie of the first person to a Walkie-Talkie of a second person. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0018]FIG. 1 depicts a system comprising a first transceiver device in communication with a second transceiver device, in accordance with embodiments of the present invention.  
     [0019]FIG. 2 depicts the first transceiver device of FIG. 1, in accordance with embodiments of the present invention.  
     [0020]FIG. 3 depicts the second transceiver device of FIG. 1, in accordance with embodiments of the present invention.  
     [0021]FIG. 4 depicts a flow chart for a method by which the first transceiver device of FIG. 1 transmits a test signal to the second transceiver device of FIG. 1 and receives a return signal from the second transceiver device, in accordance with embodiments of the present invention.  
     [0022]FIG. 5 depicts a flow chart for a method by which the second transceiver device of FIG. 1 receives a test signal from the first transceiver device of FIG. 1 and transmits a return signal to the first transceiver device, in accordance with embodiments of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0023]FIG. 1 depicts a system  10  comprising a first transceiver device  11  in communication with a second transceiver device  12 , in accordance with embodiments of the present invention. A transceiver device is defined herein as a device capable of both transmitting and receiving a signal such as an analog signal (i.e., a sequence of frequency tones) or a digital signal (i.e., a bit pattern). The signal may be an electromagnetic signal such as in the radio frequency range or in any other frequency range that can be used in wireless communication between two transceiver devices. The first transceiver device  11  is wireless. The second transceiver device  12  may be wireless or may not be wireless. Regardless of whether the second transceiver device  12  is a wireless device, the communication of signals between the first transceiver device  11  and the second transceiver device  12  is a wireless communication in both directions (i.e., from the first transceiver device  11  to the second transceiver device  12 , or from the second transceiver device  12  to the first transceiver device  11 ). An example of a transceiver device which may be used in the present invention is a Walkie Talkie, which is a wireless device. Another example of a transceiver device which may be used in the present invention is a printer that includes both a receiver and a transmitter such that the printer may communicate with a remote Personal Digital Assistant (PDA) via its receiver and transmitter. Note that the printer is not wireless if the printer is powered by a voltage source via electrical wiring that couples the printer to the voltage source. Nonetheless, the printer may engage in wireless communication with the PDA.  
     [0024] A user  17  may be coupled to the first transceiver device  11 . For example, the user  17  may be operating or using the first transceiver device  11 . A user  18  may be coupled to the second transceiver device  11 . For example, the user  18  may be operating or using the second transceiver device  12 . A transceiver device does not necessarily require the presence of a user while in operation. In some embodiments of the present invention, both users  17  and  18  are present to operate the first and second first transceiver devices  11  and  12 , respectively (e.g., in an application in which the first transceiver device  11  is a Walkie Talkie and the second transceiver device  12  is also a Walkie Talkie). In other embodiments of the present invention, the user  17  is present to operate the first transceiver device  11  and the second transceiver device  12  may operate without a user (e.g., in an application in which the first transceiver device  11  is a PDA and the second transceiver device  12  is a printer that comprises a transmitter and a receiver).  
     [0025]FIG. 2 depicts the first transceiver device  11  of FIG. 1, in accordance with embodiments of the present invention. The first transceiver device  11  comprises a transmitter  21 , a receiver,  22 , a button  23 , a processor  24 , and a memory  25 . The first transceiver device  11  may additionally comprise one or more display units such as visual display unit (e.g., meter  26 , digital display  27 , lights  28  and  29 ) or an audio display unit (e.g., speaker  30 ).  
     [0026]FIG. 3 depicts the second transceiver device  12  of FIG. 1, in accordance with embodiments of the present invention. The second transceiver device  12  comprises a transmitter  31 , a receiver,  32 , and a button  33 .  
     [0027] In FIGS.  1 - 3 , the first transceiver device  11  is transmitting signals via the transmitter  21  to the second transceiver device  12 , and the second transceiver device  12  is receiving the signals from the first transceiver device  11  via the receiver  32 . However, the user  17  of the first transceiver device  11  may recognize that there is a possibility that said signals received by the second transceiver device  12  may not be identical to said signals transmitted by the first transceiver device  11 , because of signal distortions. For example, if the signals are digital signals comprising bit patterns, then such signal distortions may comprise dropped bits, added bits (e.g., due to noise), changed bits, etc. Due to the possibility of signal distortion, the user  17  may desire to know how accurately such signals are being received by the second transceiver device  12 . The present invention enables the user  17  to obtain an indication of the extent to which the signals received by the second transceiver device  12  are the same (or different) as the corresponding signals sent by the first transceiver device  11 .  
     [0028] To test the accuracy of its signal transmissions, the user  17  may cause the transmitter  21  of the first transceiver device  11  to transmit a test signal  13  to the second transceiver device  12  where the test signal  13  may be received at the receiver  32 . The test signal  13  may be an analog signal (i.e., a sequence of frequency tones) or a digital signal (i.e., a bit pattern). Any suitable modulation scheme may be used by the first transceiver device  11  to transmit the test signal  13  to the second transceiver device  12 . The test signal  13  may be a predetermined signal who content and form is or is not a priori known to the second transceiver device  12 , or the test signal may be dynamically generated as a known function of predetermined variables (e.g., the estimated distance between the first transceiver device  11  and the second transceiver device  12 ), or the test signal may be dynamically generated as having a random aspect through use of a random number generator in the first transceiver device  11 .  
     [0029] The user  17  may activate sending the test signal  13  by pressing the button  23  to activate a test mode in the first transceiver device  11 , or by any other activation method known in the art as an alternative to pressing the button  23 . The test mode so activated enables the transmitting of the test signal  13  by the first transceiver device  11 , and also enables receipt of a return signal  14  from the second transceiver device  12  as will be described infra. Said activation of the test mode further enables computation and display of an error E associated with the return signal  14  as will be described infra.  
     [0030] After receiving the test signal  13 , the second transceiver device  12  transmits the return signal  14 , via the transmitter  31 , to the first transceiver device  11  where the return signal  14  may be received at the receiver  22 . The return signal  14  is the test signal  13  as received and retransmitted by the second transceiver device  12 . Thus, transmission of the return signal  14  is effectively a retransmission of the test signal  13  back to the first transceiver device  11 . Said receipt and retransmission of the test signal  13  by the second transceiver device  12  may be accomplished automatically without manual intervention by the user  18  of the second transceiver device  12 , if prior to said receipt of the test signal  13  the second transceiver device  12  had been placed in a test mode that enables said receiving and retransmitting by the second transceiver device  12 . The test mode in the second transceiver device  12  may be activated by pressing the button  33 , or by any other activation method known in the art as an alternative to pressing the button  33 . Additionally if the content and form of the test signal  13  is a priori known to the second transceiver device  12 , then the test mode in the second transceiver device  12  may be activated by detection of the test signal  13  based on testing signals received from the first transceiver device  11  against the a priori known content and form of the test signal  13 . As another alternative, the second transceiver device  12  could be hardwired to always be in the test mode.  
     [0031] After receiving the return signal  14 , the first transceiver device  11  determines (i.e., computes) a measure of an “error” in the return signal  14 , wherein the error denotes an extent to which the return signal  14  differs from the test signal  13 . The error may be defined mathematically in various alternative ways as is known by a person of ordinary skill in the art, and this patent discloses next, for illustrative purposes only, examples of how said error may be defined and computed.  
     [0032] If the test signal  13  (and the return signal  14 ) is an analog signal with A TEST (t) denoting the amplitude of the test signal  13  as a function of time t, and with A RETURN (t) denoting the amplitude of the return signal  14  as a function of time t, then the error E may be computed as: 
       E=| (∫ A   RETURN ( t ) dt—∫A   TEST ( t ) dt )/∫A TEST ( t ) dt )|  (1) 
     [0033] In Equation (1), the integrals are evaluated over the time interval during which the signals A TEST (t) and A RETURN (t) exist. The error E in Equation (1) may be converted to a percent by multiplying E by 100.  
     [0034] If the test signal  13  (and the return signal  14 ) is a digital signal, then the error E may be computed as: 
       E=N   ERROR   /N   TOTAL   (2) 
     [0035] In Equation (2), N ERROR  is the number of error bits in the return signal  14  and N TOTAL  is the total number of bits in the test signal  13 . An error bit is a lost bit, an added bit, or a changed bit. An error bit actually exists in the return signal  14  if the error bit is an added bit or a changed bit. An error bit does not actually exist in the return signal  14  if the error bit is a lost bit. The error E in Equation (2) may be converted to a percent by multiplying E by 100.  
     [0036] The analysis of the test signal  13  and the return signal  14 , and the computation of the error E, is performed in the first transceiver device  11  by execution of code by a processor  24 , wherein the code is stored in a memory  25 . The memory may be any type of memory known by a person of ordinary skill in te art such as a volatile memory (e.g., read-only memory (ROM)) or a non-volatile memory (dynamic random access memory (DRAM)) or both. The executable code may be hard-wired into non-volatile memory or may be accessible through a built-in mini-storage device such as a mini-tape unit within the first transceiver device  11 .  
     [0037] After the error is computed, the first transceiver device  11  may display the error E in any way that would be known by a person of ordinary skill in the art, such as in the following non-limiting examples, wherein said displaying of the error E is implemented by execution of code by the processor  24 . A first example of how the error E may be displayed is through use of a meter  26 . In FIG. 2, the meter  26  shows a bar whose extent (i.e., height) denotes the error E as a percent. A second example of how the error E may be displayed is through use of a digital display  27  (e.g., a light emitting diode (LED)), which displays the error as “87%” in FIG. 2.  
     [0038] A third example of how the error E may be displayed is through use of lightable areas  28  and  29  which may “turned on” in various ways such as lighting up, flashing, etc. If lightable area  28  is turned on then the transmission of the test signal  13  is “good” (i.e., the error E is below a maximum permissible error E MAX ), whereas lightable area  29  is turned on when the transmission of the test signal  13  is “bad” (i.e., the error E is not below E MAX ). The maximum permissible error E MAX  may be hardwired in some embodiments or may be user-selectable or user-inputable in other embodiments. While FIG. 3 shows only two lightable areas  28  and  29 , the first transceiver device  11  may have any number of lightable areas. For example, three lightable areas may be used to discriminate between a clearly good transmission, a clearly bad transmission, and a marginal transmission that is barely acceptable. If N lightable areas are present (N&gt;2) then N−1 error division values must be utilized to determine which of the N lightable areas the error E falls within. The N−1 error division values may be hardwired in some embodiments or may be user-selectable or user-inputable in other embodiments.  
     [0039] A fourth example of how the error E may be displayed is through use of an audio display such as through use of the speaker  30  or a bell, chime, etc. An audio display is analogous to the visual display afforded by the lightable areas (e.g., lightable areas  28  and  29 ) described supra. For example, words or sounds may be expressed through the speaker  30 , wherein different words or sounds denote different domains (e.g., a “good” domain, a “bad” domain, etc.) of the error E. If a bell or chime is used, different sounds or tones denote different domains of the error E.  
     [0040]FIG. 4 depicts a flow chart for a method by which the first transceiver device  11  of FIG. 1 transmits the test signal  13  to the second transceiver device  12  of FIG. 1 and receives the return signal  14  from the second transceiver device  12 , in accordance with embodiments of the present invention. Step  41  activates the test mode in the first transceiver device  11  such as by pressing the button  23  as described supra in conjunction with FIG. 2. Activating the test mode initiates transmitting the test signal  13  as either an analog signal or a digital signal. If an analog signal is to be transmitted then a fixed sequence of frequency tones is transmitted in step  41 , but if a digital signal is to be transmitted then a fixed bit pattern is instead transmitted in step  42 . After the second transceiver device  12  receives the test signal  13  and retransmits the test signal  13  as the return signal  14 , the first transceiver device  11  receives the return signal  14  in step  43 . Then the first transceiver device  11  determines the error E in the return signal  14  (relative to the test signal  13  as described supra) in step  44 . The first transceiver device  11  displays the error E in step  45 .  
     [0041]FIG. 5 depicts a flow chart for a method by which the second transceiver device  12  of FIG. 1 receives the test signal  13  from the first transceiver device  11  of FIG. 1 and transmits the return signal  14  to the first transceiver device  11 , in accordance with embodiments of the present invention. In step  51 , the second transceiver device  12  receives the test signal  13  from the first transceiver device  11 . In step  52 , the second transceiver device  12  retransmits the test signal  13 , as the return signal  14 , to the first transceiver device  11 . FIG. 5 assumes that the second transceiver device  12  is in the test mode during execution of steps  51  and  52 .  
     [0042] The second transceiver device  12  could be similar to, or identical with, the first transceiver device  11 , inasmuch as the second transceiver device  12  could transmit a test signal to a third tranceiver device and receive a return signal from the third tranceiver device in the same manner as has been described supra for the the first transceiver device  11 .  
     [0043] While embodiments of the present invention have been described herein for purposes of illustration, many modifications and changes will become apparent to those skilled in the art. Accordingly, the appended claims are intended to encompass all such modifications and changes as fall within the true spirit and scope of this invention.