Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
  • H04B1/06—Receivers
  • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
  • H04B1/06—Receivers
  • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
  • H04B1/1027—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal
  • H04B1/1036—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B15/00—Suppression or limitation of noise or interference

Definitions

• the present invention generally relates to interference suppression and, in particular, relates to dynamic filtering for adjacent channel interference("ACI") suppression.
• the present invention solves the foregoing problems by providing a dynamic filtering approach to ACI suppression.
• the dynamic approach allows for optimal attenuation of interference while minimizing undesirable attenuation of a signal of interest.
• a method for ACI suppression comprises the steps of receiving a composite signal including a signal of interest and possibly one or more adjacent channel interferers, measuring the signal of interest and the possibly one or more adjacent channel interferers, and adjusting a location (a bandwidth and a position) of at least one dynamic filter to extract the signal of interest.
• a receiver apparatus comprises an antenna configured to receive a composite signal including a signal of interest and possibly one or more adjacent channel interferers, an interference measurement circuit configured to measure the signal of interest and the possibly one or more adjacent channel interferers, at least one dynamic filter configured to extract the signal of interest, and a processor configured to adjust a location of at least one dynamic filter to extract the signal of interest.
• a receiver apparatus comprises receiving means for receiving a composite signal including a signal of interest and possibly one or more adjacent channel interferers, measuring means for measuring the signal of interest and the possibly one or more adjacent channel interferers, dynamic filtering means for extracting the signal of interest, and processing means for adjusting a location of at least one dynamic filter to extract the signal of interest.
• a machine-readable medium comprises instructions for suppressing ACI.
• the instructions comprise code for receiving a composite signal including a signal of interest and possibly one or more adjacent channel interferers, measuring the signal of interest and the possibly one or more adjacent channel interferers, and adjusting a location of at least one dynamic filter to extract the signal of interest.
• a processor for suppressing ACI is configured to measure a signal of interest and possibly one or more adjacent channel interferers in a composite signal, and adjust a location of at least one dynamic filter to extract the signal of interest.
• FIG. 1 illustrates an exemplary composite signal including a signal of interest and two adjacent channel interferers, according to one aspect of the subject technology
• FIG. 2 is a block diagram illustrating a receiver apparatus according to one aspect of the subject technology
• FIGs. 3A to 3C graphically illustrate the suppression of ACI, according to one aspect of the subject technology
• FIG. 4 is a block diagram illustrating a receiver apparatus according to one aspect of the subject technology
• FIGs. 5 A and 5B graphically illustrate the suppression of ACI, according to one aspect of the subject technology
• FIG. 6 is a flow chart illustrating a method for ACI suppression, according to one aspect of the subject technology
• FIG. 7 is a block diagram illustrating a computer system with which certain aspects of the subject technology may be implemented.
• FIG. 1 illustrates an exemplary received signal according to one aspect of the subject technology.
• the composite signal 100 includes a signal of interest 101 and two adjacent channel interferers 102 and 103.
• Each adjacent channel interferer 102 and 103 has a bandwidth (represented by the width of the interferer along the horizontal frequency axis) and a position (e.g., a frequency at which the interferer is centered).
• Some receivers may be designed with static filters for attenuating interference such as adjacent channel interferers 102 and 103. Using static filters, however, will sometimes attenuate over too small or too large a bandwidth (e.g. , not fully attenuating the interferers, or undesirably attenuating part of the signal of interest).
• a static filter may only occasionally, if ever, optimally filter a received signal.
• Receiver apparatus 200 includes an antenna 210 configured to receive composite signal 100, and to provide composite signal 100 to a measurement circuit 220.
• measurement circuit 220 measures a strength and/or a location of a signal of interest 101 and of adjacent channel interferers 102 and 103, and provides information about the measurement to processor 230.
• Processor 230 receives the information and generates, in response, instructions for adjusting a dynamic filter 240 to correspond to the location of the measured adjacent channel interferers.
• dynamic filter 240 may be a band-pass filter. In such an arrangement, dynamic filter 240 may be adjusted to align with the location of the signal of interest 101. (i.e., to pass only those frequencies of the signal of interest). Such an arrangement is illustrated in greater detail with respect to FIGs. 3A to 3C.
• FIGs. 3A to 3C illustrate the performance of a dynamic band-pass filter in accordance with certain aspects of the present disclosure.
• FIG 3A illustrates a composite signal 300 prior to filtering.
• Composite signal 300 includes a signal of interest 301 and two adjacent channel interferers 302 and 303. Accordingly, once the strength and the location of the signal of interest and of the adjacent channel interferers are measured, the processor configures a dynamic band-pass filter 305 to pass only those frequencies corresponding to signal of interest 301. The remaining frequencies, which include those of interferers 302 and 303, are attenuated by band-pass filter 305. The result of the attenuation can be seen in FIG. 3C.
• dynamic filter 240 may be a notch filter. In such an arrangement, dynamic notch filter 240 may be adjusted to have a notch corresponding to the location of an interferer.
• dynamic filter 240 is illustrated herein as a single block-level element, when dynamic filter 240 is a notch filter, it may comprise multiple dynamic notch filters, in accordance with various aspects.
• processor 230 may be configured to select which adjacent channel interferers to attenuate, and which not to attenuate, in order to achieve a best-possible SIR.
• a notch filter may be configured to have a wide enough bandwidth to attenuate multiple interferers (so long as no intermediate signal of interest is present between them).
• a dynamic filter may be a low-pass filter.
• Such an arrangement may be utilized in a receiver apparatus in which filtering takes place after baseband conversion.
• FIG. 4 illustrates one such receiver apparatus, in accordance with one aspect of the subject technology.
• Measurement circuit 430 measures a strength and a location of signal of interest 101 and of adjacent channel interferers 102 and 103 after they are converted to baseband, and provides information about the measurement to processor 440.
• Processor 440 receives the information and generates, in response, instructions for adjusting a dynamic low- pass filter (LPF) 450 to correspond to the relative strength and location of the measured signal of interest to the ACI.
• LPF dynamic low- pass filter
• measurement circuit 430 may be configured to measure only the strength of signal of interest and of adjacent channel interferers 102 and 103.
• processor 440 is configured to adjust dynamic low-pass filter 450 corresponding to the relative strength of the signal of interest to the adjacent channel interferers 102 and 103. In this regard, if one detected ACI is strong, the bandwidth of low-pass filter 450 may be reduced on the side of the signal of interest on which the stronger ACI is present.
• FIGs. 5A and 5B illustrate the performance of a dynamic low-pass filter in accordance with certain aspects of the present disclosure.
• FIG 5 A illustrates a received signal before 500 and after 510 low-pass filtering.
• Received signal 500 includes a signal of interest 501 and an adjacent channel interferer 502. Accordingly, once a strength and a location of signal of interest 501 and of ACI 502 are measured, the processor configures a dynamic low-pass filter 505 to extract signal of interest 501.
• Low-pass filter 505 is configured with enhanced attenuation on the right hand side of the filter, such that filter 505 is centered at a negative frequency.
• FIG. 5B illustrates a received signal before 520 and after 530 low-pass filtering.
• Received signal 520 includes a signal of interest 521 and two adjacent channel interferers 522 and 523.
• ACI 522 is stronger than ACI 523.
• the processor configures a dynamic low-pass filter 525 to extract signal of interest 521.
• Low-pass filter 525 is configured with enhanced attenuation on both sides, but with more greatly enhanced attenuation on the right hand side. As a result, filter 525 is centered at a negative frequency.
• an ACI strength measurement algorithm estimates signal power level P cen ter and ACI power levels P ng ht and P left with filters centered at /center, fnght and fujt Hz with a 3 dB bandwidth BWoet-
• the suppression of ACI with a low-pass filter may then proceed according to the following logic: if(Pcenter/Pnght ⁇ Threshold and P Oenter/Pi ⁇ t > Threshold) ⁇
• FIG. 6 is a flow chart illustrating a method for ACI suppression, according to one aspect of the subject technology.
• the method begins with step 601, in which a signal is received.
• the received signal includes a signal of interest and possibly one or more adjacent channel interferers.
• the composite signal is optionally converted to baseband.
• step 603 a strength and a location of the signal of interest and of the possibly one or more adjacent channel interferers are measured.
• the location of a dynamic filter is adjusted to extract the signal of interest.
• the measurement step 603 may include measuring only the strength of the signal of interest and of the possibly one or more adjacent channel interferers.
• FIG. 7 is a block diagram that illustrates a computer system 700 upon which an aspect may be implemented.
• Computer system 700 includes a bus 702 or other communication mechanism for communicating information, and a processor 704 coupled with bus 702 for processing information.
• Computer system 700 also includes a memory 706, such as a random access memory (“RAM”) or other dynamic storage device, coupled to bus 702 for storing information and instructions to be executed by processor 704.
• Memory 706 may also be used for storing temporary variable or other intermediate information during execution of instructions to be executed by processor 704.
• Computer system 700 further includes a data storage device 710, such as a magnetic disk or optical disk, coupled to bus 702 for storing information and instructions.
• Computer system 700 may be coupled via I/O module 708 to a display device (not illustrated), such as a cathode ray tube ("CRT") or liquid crystal display (“LCD”) for displaying information to a computer user.
• a display device such as a cathode ray tube ("CRT") or liquid crystal display (“LCD”)
• An input device such as, for example, a keyboard or a mouse may also be coupled to computer system 700 via I/O module 708 for communicating information and command selections to processor 704.
• ACI suppression is performed by a computer system 700 in response to processor 704 executing one or more sequences of one or more instructions contained in memory 706. Such instructions may be read into memory 706 from another machine -readable medium, such as data storage device 710.
• main memory 706 causes processor 704 to perform the process steps described herein.
• processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in memory 706.
• hard-wired circuitry may be used in place of or in combination with software instructions to implement various aspects. Thus, aspects are not limited to any specific combination of hardware circuitry and software.
• machine-readable medium refers to any medium that participates in providing instructions to processor 704 for execution. Such a medium may take many forms, including, but not limited to, non-volatile media, volatile media, and transmission media.
• Non-volatile media include, for example, optical or magnetic disks, such as data storage device 710.
• Volatile media include dynamic memory, such as memory 706.
• Transmission media include coaxial cables, copper wire, and fiber optics, including the wires that comprise bus 702. Transmission media can also take the form of acoustic or light waves, such as those generated during radio frequency and infrared data communications.
• Machine -readable media include, for example, floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH EPROM, any other memory chip or cartridge, a carrier wave, or any other medium from which a computer can read.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Noise Elimination (AREA)

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• 2008
  • 2008-07-01 US US12/165,667 patent/US20100002815A1/en not_active Abandoned
• 2009
  • 2009-06-30 BR BRPI0914113A patent/BRPI0914113A2/pt not_active IP Right Cessation
  • 2009-06-30 EP EP09774396A patent/EP2313981A1/en not_active Withdrawn
  • 2009-06-30 RU RU2011103461/08A patent/RU2466498C2/ru not_active IP Right Cessation
  • 2009-06-30 KR KR1020117002610A patent/KR101230355B1/ko not_active Expired - Fee Related
  • 2009-06-30 CN CN200980124970XA patent/CN102077473A/zh active Pending
  • 2009-06-30 CA CA2728305A patent/CA2728305C/en not_active Expired - Fee Related
  • 2009-06-30 JP JP2011516839A patent/JP2011527160A/ja active Pending
  • 2009-06-30 WO PCT/US2009/049331 patent/WO2010002946A1/en not_active Ceased
  • 2009-07-01 TW TW098122284A patent/TWI436600B/zh not_active IP Right Cessation

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