Beacon detection structures, systems and processes for interference testing

A receiver is provided that receives signals from a device under test (DUT) for one or more modes of operation. For each mode, the system detects beacon transmission signals from the DUT, and counts the number of beacons for a period of time. If the count is not consistent with an expected count, e.g. a stored value, the system may preferably provide an output to indicate that there is a problem with the DUT. If the count is consistent with the expected count, the system may preferably perform further testing for other modes of operation. If the count output of the DUT is consistent with expected counts over each of the operation modes, the system may provide an indication that the DUT has passed the beacon tests.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates generally to testing structures and processes for wireless or RF (radio frequency) communications systems. More particularly, the invention relates to test structures and processes for the determination of interference between wireless signals.

2. Description of the Background Art

It is necessary to equip receivers, transmitters, and transceivers with antennas that efficiently radiate, i.e. transmit and/or receive desired signals to/from other elements of a network to provide wireless connectivity and communication between devices in a wireless network, such as in a wireless PAN (personal area network), a wireless LAN (local area network), a wireless WAN (wide area network), a cellular network, or virtually any other radio network or system.

Cable gateways and wireless routers commonly comprise a plurality of radios, e.g. two radios, such as comprising a first, e.g. cable modem radio, and a second, e.g. Wi-Fi radio, wherein the radios operate with different frequencies. However, the sub-harmonic or harmonic frequencies of a first radio, e.g. a cable modem radio, may land upon the frequency band of a second radio, e.g. within a 2.4 GHz or 5.0 GHz band of a Wi-Fi band, thus potentially causing interference between the signals.

While tests of the performance of each of the radios for a cable gateway or router may readily be performed during development or manufacture, individual testing of radio performance does not detect overlap, i.e. interference, between bands.

It would therefore be advantageous to provide a structure and process that readily detects interference between two or more radio bands. The development of such a structure, system and process would provide a significant technical advance.

SUMMARY OF THE INVENTION

A testing structure and system are provided that receives signals from a device under test (DUT) for one or more modes of operation. For each mode, the system detects beacon transmission signals from the DUT, and counts the number of beacons, i.e. pulses, for a period of time. If the count is not consistent with an expected count, e.g. a stored value, the system may preferably provide an output to indicate that there is a problem with the DUT. If the count is consistent with the expected count, the system may preferably perform further testing of other modes of operation. If the count output of the DUT is consistent with expected counts over an operation mode, the system may provide an indication that the DUT has passed the corresponding beacon test. During product development, failure during beacon testing may preferably be remedied or otherwise addressed, and the device, e.g. a prototype, or an alternate device, may be retested, to determine if interference between bands has been eliminated.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a partial schematic view of an exemplary wireless device10, e.g. such as but not limited to a cable gateway or wireless router10. The exemplary device10seen inFIG. 1comprises an enclosure12, a plurality of radio modules14, e.g.14a-14e, and a corresponding plurality of antennas16, e.g.16a-16e, for sending and/or receiving corresponding wireless signals18, e.g.18a-18e.

The first exemplary radio module14aseen inFIG. 1comprises a cable modem module14a, while the second exemplary radio module14eseen inFIG. 1comprises a Wi-Fi radio module14e.

While the radio modules14aand14eare typically configured to operate with different frequencies, the sub-harmonic or harmonic frequencies of a first radio14a, e.g. a cable modem radio14a, may land upon the frequency band of a second radio14e, e.g. within a 2.4 GHz or 5.0 GHz band of a Wi-Fi band, which may result in interference20between the two signals18a,18e.

While tests of the performance of each of the radio modules14for a cable gateway or router may readily be performed during design, development or manufacture, individual testing of radio performance for the modules14does not detect overlap, i.e. interference, between bands. Therefore, even if a wireless device passes such individual tests, the device may not work as expected during one or more operating modes, due to interference between wireless bands.

For example, a wireless signal18typically comprises a periodic series of beacons160, e.g.160a-160i(FIG. 5,FIG. 6), such as having a beacon interval172(FIG. 6), through which packets of information are transmitted from the device10. If the wireless signal18is corrupted or otherwise modified due to interference20, the resultant transmission signal158, e.g.158b(FIG. 6), may lose one or more of the beacons160. For example, beacon160gof a received transmission158aseen inFIG. 5is missing from the received transmission158bseen inFIG. 6.

FIG. 2is a schematic diagram of an exemplary structure40for beacon testing of a device under test (DUT)10. As seen inFIG. 2, radio signals18, e.g.18a,18emay preferably be transmitted during testing100(FIG. 4) from a device under test (DUT)10. The wireless signals18are received by a receiver42, e.g. an amplitude modulation (AM) receiver42, through an appropriate transmitter44.

An exemplary AM receiver42may typically correspond to medium wave (MW) signals having a range from 535 kHz to 1705 kHz, such as corresponding to the current North American MW broadcast band. An alternate exemplary AM receiver42my preferably correspond to medium wave (MW) signals having a range from 526.5 kHz to 1606.5 kHz, such as corresponding to the current European MW broadcast band. Other specific AM receivers42may preferably be used, such as configured to receive all the beacons, i.e. pulses160over the intended frequency ranges of all the radio modules18a-18e.

As seen inFIG. 2, wireless signals18, e.g.18a,18e, that are received at the receiver42are input to a processor48associated with a test system50, which may preferably be used to detect the presence of interference between radio bands, such as through the use of pulse counts49and comparison to stored or expected values52. The processor48may preferably provide an output54that corresponds to the results of the counts of beacons160, and the presence of any interference120between radio bands18.

FIG. 3is a block schematic diagram60of a machine in the exemplary form of a computer system50within which a set of instructions may be programmed to cause the machine to execute the logic steps of the enhanced beacon detection for interference testing system50. In alternative embodiments, the machine may comprise a network router, a network switch, a network bridge, personal digital assistant (PDA), a cellular telephone, a Web appliance or any machine capable of executing a sequence of instructions that specify actions to be taken by that machine.

The exemplary computer system50seen inFIG. 3comprises a processor48, a main memory62, and a static memory64, which communicate with each other via a bus66. The computer system50may further comprise a display unit68, for example, a light emitting diode (LED) display, a liquid crystal display (LCD) or a cathode ray tube (CRT). The exemplary computer system50seen inFIG. 3also comprises an alphanumeric input device70, e.g. a keyboard70, a cursor control device72, e.g. a mouse or track pad72, a disk drive unit74, a signal generation device76, e.g. a speaker, and a network interface device78.

The disk drive unit74seen inFIG. 3comprises a machine-readable medium80on which is stored a set of executable instructions, i.e. software82, embodying any one, or all, of the methodologies described herein. The software82is also shown to reside, completely or at least partially, as instructions84,86within the main memory62and/or within the processor48. The software82may further be transmitted or received90over a network92by means of a network interface device78.

In contrast to the exemplary enhanced beacon detection for interference testing system50discussed above, an alternate enhanced beacon detection for interference testing system50or node50may preferably comprise logic circuitry instead of computer-executed instructions to implement processing entities. Depending upon the particular requirements of the application in the areas of speed, expense, tooling costs, and the like, this logic may be implemented by constructing an application-specific integrated circuit (ASIC) having thousands of tiny integrated transistors. Such an ASIC may be implemented with CMOS (complimentary metal oxide semiconductor), TTL (transistor-transistor logic), VLSI (very large systems integration), or another suitable construction. Other alternatives include a digital signal processing chip (DSP), discrete circuitry (such as resistors, capacitors, diodes, inductors, and transistors), field programmable gate array (FPGA), programmable logic array (PLA), programmable logic device (PLD), and the like.

It is to be understood that embodiments may be used as or to support software programs or software modules executed upon some form of processing core, e.g. such as the CPU of a computer, or otherwise implemented or realized upon or within a machine or computer readable medium. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine, e.g. a computer. For example, a machine readable medium includes read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other form of propagated signals, for example, carrier waves, infrared signals, digital signals, etc.; or any other type of media suitable for storing or transmitting information.

Further, it is to be understood that embodiments may include performing computations with virtual, i.e. cloud computing. For the purposes of discussion herein, cloud computing may mean executing algorithms on any network that is accessible by internet-enabled devices, servers, or clients and that do not require complex hardware configurations, e.g. requiring cables, and complex software configurations, e.g. requiring a consultant to install. For example, embodiments may provide one or more cloud computing solutions that enable users, e.g. users on the go, to print using dynamic image gamut compression anywhere on such internet-enabled devices, servers, or clients. Furthermore, it should be appreciated that one or more cloud computing embodiments include printing with dynamic image gamut compression using mobile devices, tablets, and the like, as such devices are becoming standard consumer devices.

FIG. 4is a flowchart of an exemplary process100for beacon detection for interference testing of a device under test (DUT)10, such as using the enhanced testing system50seen inFIG. 2andFIG. 3.

In the exemplary process100seen inFIG. 4, a device10to be tested is placed in proximity to an AM receiver42, which is configured to receive wireless signals18, e.g.18a,18e, sent from the radio modules14, e.g.14a,14e. The device under test10is then operated104at one or more modes. The system50receives106the incoming beacon signals160, e.g.160a-160i(FIG. 5,FIG. 6) from the device under test DUT10, and the number of beacons160are counted108for a determined period156(FIG. 5,FIG. 6) of time152(FIG. 5,FIG. 6).

The system50then determines110if the count49,162of received beacon pulses160is consistent with the required set of pulses160, e.g.160a-160i, for the time period156, which is indicative that all signal pulses160for a radio band18have been received for the time period156. If the determination110is negative112, e.g. for a period wherein10pulses should have properly been counted, and the detected count is less than ten, e.g. from zero to nine (FIG. 6), the system10determines that there may be an interference problem with the device under test10. For example, a loss of one or more beacon pulses160in a count162may indicate that interference from one or more other radio modules14in the device under test10has resulted in the failure of the received transmission signal158, e.g.158b(FIG. 6).

As also seen inFIG. 4, if the determination110is positive116, the system50may log that all signal pulses160, e.g.160a-160i, for a radio band have been received for the time period156, and, if other frequencies118need to be tested120, the process may preferably return122, for the next mode of DUT operation, and proceed to test other operation modes.

If there are no more DUT operation modes to test124, i.e. if the device under test10has passed all modes of beacon detection, the system50may provide an output128or otherwise provide a display and/or signal that indicates the positive result.

FIG. 5is a first chart150that shows an exemplary beacon count162within a time period156, wherein the count162is consistent with an expected count162.FIG. 6is a second chart170that shows an exemplary beacon count162within a time period156, wherein the count is less than an expected count162. As seen inFIG. 5andFIG. 6, a signal158, e.g.158a,158b, which is received through the AM receiver42(FIG. 2,FIG. 3), varies in amplitude154as a function of time152, such as corresponding to a series of beacon intervals172(FIG. 6). The received wireless signals158define a series of peaks, i.e. beacons160, which meet and/or exceed a threshold level164. One or more of the beacons160, e.g.160h(FIG. 6), from a single wireless signal18, e.g. such as but not limited to a Wi-Fi signal18e(FIG. 2), may be altered, corrupted, or substantially cancelled, by interference20from a different wireless signal18, e.g. such as but not limited to a cable modem signal18a(FIG. 2). For example, sub-harmonic or harmonic frequencies from a cable modem radio14amay land upon the Wi-Fi band18e(FIG. 2), e.g. such as but not limited to 2.4 gigahertz or 5 gigahertz frequencies.

In an exemplary embodiment of a wireless device10, having a cable modem module14a, and a Wi-Fi radio module14e, and exemplary time period156may comprise 100 milliseconds, wherein a wireless signal18efrom the Wi-Fi radio module16emay transmit ten beacons106, e.g.106a-106i, within the 100 millisecond period156. The stored, i.e. expected beacon value52(FIG. 2) for such a signal16e, without interference20, may therefore correspond to a value of ten for the 100 millisecond period156. Similarly, an equivalent value may be provided for a different chosen period156. In the above example, the stored, i.e. expected beacon value52(FIG. 2) for such a signal18e, without interference20, may therefore correspond to a value of fifty for a 500 millisecond period156.

The beacon level detection for interference structure40, system50, and process100provides a significant improvement in for design and development of wireless devices10, without the need to integrate more complex waveform analysis software and hardware. The testing of wireless configurations may readily be performed, and changes in performance between different configurations may be efficiently tested.

For example,FIG. 7is a schematic view200of a first board layout for a wireless device10a. Testing100of such a wireless device10amay indicate114(FIG. 4) a potential interference problem during one or more operation mode104(FIG. 4). An alternate wireless device10, e.g.10b(FIG. 8) may also be tested for possible interference120. For example,FIG. 8is a schematic view220of a modified board layout for a wireless device10b, which may comprise one or more differences as compared to the configuration of the wireless device10aseen inFIG. 7, such as comprising any of:a difference in board layout202, e.g.202a,202b;a difference between antenna designs or location16;on-board shielding224;other shielding226;cable routing;enclosure design or configuration12, e.g.12a,12b;operational modes; and/orother parameters.

The design of the second device10bmay be considered at any time, such as to provide a comparative development prototype concurrently with the first device10a, or as developed later, as a result of the testing100and detected interference114of the first device10a.

FIG. 9andFIG. 10provide further examples of different device configurations10cand10d, that may preferably be tested100and compared to each other, or to other wireless device configurations10, e.g.10a, and10b. For example,FIG. 9is a schematic view240of the internal configuration for a wireless device10c, which comprises separate analog signal processing boards (ASPB)202, e.g.202c,202d, with shielding224,226between boards202c,202d, and antennas16a,16e.FIG. 10is a schematic view260of a modified internal configuration for a wireless device10d, which comprises separate boards202, e.g.202e,202f, with alternate shielding262between boards202e,202f, and antennas16a,16e. As also seen inFIG. 10, the layout of the wireless device10dmay preferably provide a different separation distance between one or more components, such as between the antennas16aand16e.

The beacon level detection for interference structure40, system50, and process100therefore provides a versatile development tool, whereby a large number of potential configurations for wireless devices10may readily be tested and evaluated, without the need to integrate complex waveform or spectrum analysis software and hardware. The testing of one or more wireless configurations may readily be performed, to rapidly develop wireless devices10that have high efficiency and are easy to manufacture.