Abstract:
A system and method for analyzing the real-time performance of a communication device. An aspect of the present invention records information input to the communication device during real-time operation of the communication device. A playback device or module may execute a model of the communication device in a non-real-time environment according to the recorded real-time input information. System execution in the non-real-time playback environment may, therefore, be equivalent to the original operation of the communication device that occurred in real-time. Accordingly, situations that occur in real-time may be efficiently recreated in non-real-time playback. An operator may analyze the past real-time performance of the communication device using the playback device or module, the recorded real-time input information, and a debugger utility if desired, without conducting additional trials to reproduce the desired operational situation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE 
     This patent application claims the benefit of U.S. Provisional Application No. 60/480,666, filed Jun. 23, 2003, the contents of which are hereby incorporated herein by reference in their entirety. 
    
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     [Not Applicable] 
     SEQUENCE LISTING 
     [Not Applicable] 
     MICROFICHE/COPYRIGHT REFERENCE 
     [Not Applicable] 
     FIELD OF THE INVENTION 
     The present invention relates generally to operational analysis of real-time communication systems. The present invention relates more specifically to operational analysis of communication devices. 
     BACKGROUND OF THE INVENTION 
     Real-time systems are often difficult to analyze. Such is the case for both hardware and software based systems. In hardware based systems, for example, an analyst may not be able to access a desired signal, much less, access the desired signal and causes of such signal in real-time. In fact, in some systems, even the mere act of accessing an available signal may have detrimental effects on the system operation. 
     In software based systems, for example, standard analysis techniques such as setting breakpoints in a debugging environment and stepping through a software program do not typically work well for real-time systems. For example, once the software program execution is stopped in the debugger, the relationship between the program&#39;s execution and the real-time chain of events is broken. Events continue to occur in real-time while the program is executed at a completely different non-real-time rate under the control of the debugger. Such single stepping through a program may not reveal the performance information sought since, by the time the section of software code of interest is executed, the conditions causing the event of interest have passed. 
     Also in software-based systems, for example, engineers have traditionally relied on debug messages in the program that normally include text strings and indicate which events are taking place, which piece of code is executing, and the values of certain parameters. However, such a technique does not provide a complete performance analysis solution since such messages cannot describe everything happening in the system. Using this traditional technique, debug messages would likely have to be incorporated into every part of the program where execution flow changes (e.g., in every “if” and “while” statement). The amount of debug messages may be excessive in such a case, and in fact, the execution of such debug messages may interfere with real-time system timing. 
     Further, when input data to a real-time system (e.g., a communication system) changes from one operation to the next, operational analysis becomes increasingly difficult. An analyst may need to perform a multitude of test trials before a problem can be reproduced, analyzed, understood and fixed. Another complication that may occur (e.g., in communication systems) is when the problem occurs only at a remote site due to the variance of the operational conditions. A trip to the remote site by one or more engineers may be required and can be time consuming and expensive. 
     Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     A system and method are provided for analyzing the performance of a real-time communication device (e.g., an Asymmetric Digital Subscriber Line (ADSL) modem). An aspect of the present invention fully records real-time information (e.g., samples, data and commands) that is input to a real-time communication device over a period of time. A playback device or module executes a model of the real-time communication device in a non-real-time environment according to the recorded information. System execution in the non-real-time playback environment is, therefore, equivalent to the original execution of the real-time communication device that occurred in real-time. Accordingly, any problems that occurred in real-time may be repeated in non-real-time playback. An operator may, for example, analyze the past real-time performance of the real-time communication device using the playback device or module, the recorded information, and a debugger utility if desired, without conducting additional trials to reproduce the operational situation of interest. 
     These and other advantages, aspects and novel features of the present invention, as well as details of illustrative aspects thereof, will be more fully understood from the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating a real-time operating environment supporting operational analysis of a real-time communication device via recording of input information, in accordance with various aspects of the present invention. 
         FIG. 2  is a diagram illustrating a non-real-time playback environment for supporting operational analysis of the operation of the real-time communication device of  FIG. 1 , for example, in accordance with various aspects of the present invention. 
         FIG. 3  is a flowchart illustrating a method for analyzing the operation of the real-time communication device of  FIG. 1 , for example, using the playback environment of  FIG. 2 , for example, in accordance with various aspects of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a diagram illustrating aspects of a real-time operating environment  100  supporting operational analysis of a real-time communication device  101  via recording of input information, such as data, input samples, and commands, in accordance with various aspects of the present invention. The real-time communication device  101  may, for example, be a real-time high-speed communication device, like an ADSL modem or cable modem. The exemplary real-time operating environment  100  includes a real-time communication device  101  and a memory device  102 , such as a hard disk, for example. The real-time communication device  101  includes a recording platform  103  for causing the recording of input data  107 , input samples  105 , and commands  106  to the memory device  102  as recorded input data, input samples and commands  104 . The real-time communication device  101  is coupled to the memory device  102 . 
     As mentioned previously, the real-time communication device  101  may be, for example, an ADSL modem. ADSL (Asymmetric Digital Subscriber Line) is a technology used to deliver broadband service using existing copper telephone lines. ADSL supports data rates from approximately 384 Kbps to 25 Mbps, and rising, when receiving data (i.e., the downstream rate), and from approximately 32 Kbps to 3 Mbps, and rising, when sending data (i.e., the upstream rate). The different downstream and upstream rates define the asymmetry. 
     A special communication device known as an ADSL modem is used to provide ADSL communication. In general, a modem (modulator/demodulator) is a communication device or program that enables a personal computer (PC) to transmit data over, for example, cable or telephone lines. PC information is stored and utilized in a digital form whereas information that is transmitted over telephone lines is transmitted in the form of analog signals. A modem converts between the digital and analog information forms. A modem may be internal or external to a PC. Two examples of high-speed modems are ADSL modems and cable modems. In general, as defined herein, “high-speed” refers to any communication device operating above 56 Kbps. 
       FIG. 1  illustrates the communication device  101  in a configuration and environment similar to an ADSL modem configuration and environment. However, the communication device  101  aspect of the present invention disclosed herein is by no means limited to an ADSL modem, nor is the communication media limited to telephone line communication. For example, the communication device  101  may be a cable modem, optical modem, radio frequency modem, or other known communication or interface device. The communications media may be, for example, telephone wire, television cable, optical cable, radio interface, or other known media. 
     Referring to  FIG. 1 , the communication device  101  converts the input samples  105  from the telephone line side of the communication device  101  to output data  108  on the PC side of the communication device  101 . Conversely, the communication device  101  converts the input data  107  from the PC side of the communication device  101  to the output samples  109  on the telephone line side of the communication device  101 . The commands  106  arrive at the communication device  101  from the PC side and control the mode of operation of the communication device  101 . For example, one command may be “make a connection,” and another command may be “send data.” The communication device  101  may also output various indications  110  to the PC side. The input samples  105  may arrive at the communication device  101  in analog form and be converted to digital form by the communication device  101 . The input data  107  and the commands  106  may arrive at the communication device  101  in digital form. Note that though the exemplary communication device  101  is a computer communication device, such as an ADSL modem, the scope of various aspects of the present invention should by no means be limited to characteristics of computer communication devices. 
     The recording platform  103  may reside on or with the communication device  101 . For example, the communication device  101  may include a memory  120 , processor  121  and recording platform  103 . The recording platform  103  may include hardware, software, or a combination thereof. For example, a processor  121  on the communication device  101  may execute recording platform  103  instructions to cause the digitized input samples  105 , input data  107  and commands  106  to be stored as recorded input samples, input data, and commands  104 . Alternatively, for example, the recording platform may be a self-contained circuit or a stand-alone device that is communicatively coupled to other components of the communication device  101 . Alternatively, for example, the recording platform may be integrated onto a communication device integrated circuit or multi-chip module. Accordingly, the scope of various aspects of the present invention should not be limited to particular characteristics and configurations of the recording platform  103 . 
     The recording platform  103  may, for example, cause the information to be stored in exactly the same sequence as the information arrives as the communication device  101 . The recording platform  103  may, for example, cause the information to be stored on a memory device  102  of a computer that is communicationally coupled to the communication device  101 . Such a computer may, for example, be a computer directly connected to the communication device  101 , or may be a computer coupled to the communication device  101  through a computer network. 
       FIG. 2  is a diagram illustrating a non-real-time playback environment  200  for analyzing the operation of the real-time communication device  101  (e.g., an ADSL modem) of  FIG. 1 , for example, in accordance with various aspects of the present invention. Referring to  FIG. 2 , the non-real-time playback environment  200 , which may also be referred to as a debug environment, includes a memory device  102  and a computer  202  running debugging software  205 , which may also be referred to as a “debugging tool.” 
     The memory device  102  may, for example, be the same memory device  102  discussed previously with regard to  FIG. 1 . For example, the memory device  102  may be a hard disk of a computer that is communicatively coupled to the communication device  101 , or the hard disk of a computer that was communicatively coupled to the communication device  101  at some point during real-time operation of the communication device  101 . The memory device  102  may include recorded information, such as, for example, input data, input samples and commands  104  that were recorded in the real-time operating environment  101  discussed previously. The memory device  102  may alternatively contain any input/output information of interest. 
     The computer  202  may, for example, be a personal computer (PC) or a network workstation. Such a computer  202  typically has a memory device containing software instructions and a processor for executing the software instructions. The computer  202  includes playback software  204 , which includes a model of the communication device  101 . For example, as illustrated in  FIG. 2 , the playback software  204  may include a bit-exact software model of the communication device  101  (e.g., an ADSL modem). In accordance with an aspect of the present invention, the playback software  204  may, for example, run as an application on a PC or workstation under a WINDOWS or LINUX operating system. The playback software  204  may, for example, reside on a hard disk of the computer  202  or a compact disc or DVD. 
     Alternatively, the computer  202  may be any playback device (or hardware or software module) that may operate according to the input information stored in the memory device  102 . For example and without limitation, such a playback device may include hardware or software modeling components. Such a playback device may, for example, include various components of the actual communication device being modeled. Accordingly, the scope of various aspects of the present invention should by no means be limited to a particular configuration of playback device (or module or platform). 
     The computer  202  is coupled to the memory device  102 . The memory device  102  may be external or internal to the computer  202 . The coupling between the computer  202  and the memory device  102  may be as simple as a dedicated cable or as complex as the Internet. The memory device  102  may be a hard drive in the computer  202  on which also resides the playback software  204  and debugging software  205 . 
     In accordance with an aspect of the present invention, an operator executes the playback software  204  on the computer  202 . The playback software  204 , when executed, causes the reading of the recorded input information from the memory device  102 . The playback software  204  then operates the communication device model according to the recorded input data, input samples and commands  104 . The operator may also execute debugging software  205 , which allows the operator to control and observe the operation of the communication device model as the communication device model operates in accordance with the recorded input information. 
     In accordance with an aspect of the present invention, the recorded input information  104  are the exact data, samples, and commands recorded in the real-time operating environment  100  over a period of time. Also, the playback software  204  may be a bit-exact model of the operation of the communication device  101  (e.g., an ADSL modem). Therefore, any communication device  101  behaviors that occurred in the real-time operating environment  100  during the period of time over which the input data  107 , input samples  105 , and commands  106  were recorded will recur during analysis in the non-real-time playback environment  200 . 
       FIG. 3  is a flowchart of a method  300  for analyzing the operation of the real-time communication device  101  of  FIG. 1 , for example, using the playback environment  200  of  FIG. 2 , for example, in accordance with various aspects of the present invention. In step  301 , a communication device (such as an ADSL modem) is operated in real-time. 
     In step  302 , while the communication device is operating in real-time, information input to (and perhaps output from) the communication device is recorded. Such real-time information may include the input data, input samples, and commands discussed previously. Alternatively such real-time information may include many other types of real-time information associated with the communication device. 
     The communication device may gather the real-time information internally. The communication device may direct the recording of the real-time information in a memory device external to the communication device. For example, the communication device may cause the real-time information to be written to the hard drive of a computer connected to the communication device. The communication device may optionally be driven as a WINDOWS operating system device driver in a computer and write the real-time information directly to the hard drive of the computer. The communication device may also cause the real-time information to be sent to a computer coupled to the communication device through a computer network, such as a local area network or the Internet. 
     In step  303 , the recorded input information, such as, for example the real-time recorded input data, input samples, and commands are read into a model of the communication device in non-real-time. This step may be accomplished, for example, by the execution of computer instructions in playback software on a computer. Such playback software may, for example, when executed by a processor, cause the reading of the recorded real-time information into a software model of the communication device (e.g., into a software model of an ADSL modem). The software model may, for example, be a bit-exact model, producing results that are the same as the original device that the software model is modeling. The playback software may drive, or execute, the model of the communication device in non-real-time in accordance with the recorded real-time information. Consequently, the model of the communication device may mimic, perhaps exactly, the real-time operation of the communication device. 
     In step  304 , the operation of the software model on the recorded input data and commands is observed in order to analyze, in non-real-time, the real-time performance of the communication device. For example, an operator may, through the utilization of aspects of the invention, debug the operation of a faulty communication device. An operator may, through the use of a software debugger tool, execute the playback instructions, and observe and control the operation of the communication device model in response to the recorded real-time information. The operator may thus recreate and observe a real-time operational situation of interest, in order to ascertain the real-time response of the actual communication device in response to the real-time stimuli received by the device. 
     As an example, refer to  FIG. 1  and an ADSL modem example. In the real-time operating environment  100 , the communication device  101  (e.g., an ADSL modem) may operate over a period of time on the input data  107 , input samples  105 , and commands  106 . During real-time operation, the recording software platform  103  within the communication device  101  causes the recording of the input data  107 , input samples  105 , and commands  106 , perhaps writing this information directly to the memory device  102  (e.g., a hard disk). In such a scenario, the communication device  101  may be a PCI card that is plugged into a PC, which in turn includes the memory device  102 . 
     Referring then to  FIG. 2 , in the non-real-time playback environment  200 , the computer  202  (e.g., a PC), which may be the same computer that houses the memory device  102 , reads the recorded input data, input samples, and commands  104  from the memory device  102 . The computer  202  runs the playback software  204  that operates a model of the communication device  101  in accordance with the recorded input data, input samples, and commands  104  in non-real-time. This provides the opportunity for an operator to analyze the real-time operation of the communication device  101  in non-real-time. 
     In accordance with an aspect of the present invention, the memory device  102  (e.g., a hard disk) and the communication device  101  (e.g., an ADSL modem) may be integrated into the computer  202  (e.g., a PC). In accordance with an alternative aspect of the present invention, the communication device  101  may be a standalone device that is connected to the phone lines on one end and to a computer  202  on the other end via, for example, an Ethernet connection. In such a configuration, the communication device  101  may forward the input data, input samples, and commands to the computer  202  over the Ethernet connection. The computer  202  then may include recording software instructions, which when executed, cause the capture and recordation of the input data, input samples, and commands to the memory device  102 . 
     In summary, a system, apparatus and method are provided for analyzing the real-time operation of a communication device, such as an ADSL modem or a cable modem, in non-real-time. 
     While the invention has been described with reference to certain aspects and embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.