Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
  • H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding

Definitions

• a method for dynamically allocating forward error encoding monitors bandwidth utilization for transmitting data, and dynamically adjusts a level of forward error encoding, based on the bandwidth utilization for data, to substantially occupy available bandwidth not being utilized.
• a communications system which includes a data formatting unit adapted to dynamically adjust the level of forward error encoding based on data bandwidth utilization such that the level of forward error encoding substantially occupies unutilized bandwidth, a transmitter adapted to transmit a data signal formatted by the data formatting unit, and a receiver adapted to receive the transmitted signal containing data and forward error encoding.
• FIG. 1 is a block diagram of a communication system according to one embodiment of the present invention.
• Figure 2 is a block diagram of a data formatting unit according to one embodiment of the present invention.
• Figure 3 is a block diagram of a forward error encoder according to one embodiment of the present invention.
• Figure 4 is a flow chart showing a method of dynamically allocating forward error encoding according to one embodiment of the present invention.
• the present invention enables more effective use of available bandwidth and provides a system and method for improving data protection from bit errors.
• the present invention accomplishes these functions by dynamically adjusting the level of forward error encoding based on the amount of bandwidth being used for transfer of data. Hence, as less than a maximum amount of bandwidth available is used for data transfer, forward error encoding is increased to substantially fill the available amount of bandwidth.
• FIG. 1 is a block diagram of a communication system 100 according to one embodiment of the present invention.
• communication system 100 includes a sensor unit 102 coupled to a payload processing subsystem 104.
• Payload processing subsystem 104 includes a data processing unit 106 adapted to process data received from sensor unit 102, and a data formatting unit 108 coupled to data processing unit 106.
• Data formatting unit 108 is adapted to format the data for transmission from transmitter 110 to receiver 112.
• data formatting unit 108 and data processing unit 106 are arranged as one physical unit.
• data formatting unit 108 and data processing unit 106 can be arranged as physically separate units that perform their respective functions.
• data formatting unit 108, data processing unit 106 and transmitter 110 are located in a spaceborne platform (e.g., satellite, spacecraft, etc.), and receiver 112 is located in a receiving station on Earth.
• data formatting unit 108 is adapted to monitor the amount of bandwidth being utilized for data.
• data formatting unit 108 monitors a transmission buffer to determine the amount of bandwidth utilization for data, and adjusts the amount of bandwidth used for forward error encoding based on the amount of bandwidth utilized for data. If data formatting unit 108 determines that the amount of bandwidth being utilized for data is less than a predetermined threshold value, the forward error encoding is increased to utilize the unused bandwidth.
• data formatting unit 108 ensures that a minimum amount of forward error encoding is always used.
• Data formatting unit 108 is also adapted to format data and forward error encoding for transmission.
• data formatting unit 108 is adapted to format data and forward error encoding for transmission in a packet switched network.
• data formatting unit 108 can format data and forward error encoding for transmission in circuit switched and cell relay networks.
• transmitter 110 receives the formatted data containing data and forward error encoding from payload processing subsystem 104, and transmits the formatted data to receiver 112.
• transmitter 110 transmits the formatted data over a wireless radio link.
• transmitter 110 can be adapted to transmit data over other suitable communication media such as, for example, coaxial cable, copper wire, optical fiber, etc.
• Receiver 112 is adapted to receive the transmitted data and correct any bit errors in the transmitted data using the forward error encoding also received from transmitter 110.
• receiver 112 is adapted to automatically detect the level of forward error encoding received.
• the transmitted forward error encoding can include one or more bits indicating to receiver 112 the level of forward error encoding used.
• FIG 2 is a block diagram of a data formatting unit 200, which can be used to implement data formatting unit 108 shown in Figure 1.
• data formatting unit 200 includes a transmission buffer 202 and bandwidth monitor 204.
• Bandwidth monitor 204 is coupled to transmission buffer 202 in order to monitor the amount of bandwidth being utilized for data. If the amount of bandwidth being utilized is less than a predetermined threshold value, bandwidth monitor 204 conveys a signal to forward error encoder (FEE) 206, which indicates the level of forward error encoding to be used.
• FEE forward error encoder
• bandwidth monitor 204 can convey a signal to forward error encoder 206, which indicates whether or not the current amount of bandwidth being utilized for data exceeds a predetermined threshold value. Forward error encoder 206 then determines the level of forward error encoding to be used based on the signal received from bandwidth monitor 204 and the data from buffer 202.
• framer 208 receives the forward error encoding generated by forward error encoder 206 and the data from buffer 202.
• Framer 208 formats the data and forward error encoding for transmission over a communication media, such as, for example, a wireless radio link, optical fiber, coaxial cable, etc.
• framer 208 formats the data in packets according to a given protocol for transmission by transmitter 110 (e.g., shown in Fig. 1).
• framer 208 can format the data in another suitable format, such as cells in a cell relay network.
• bandwidth monitor 204 is implemented as an application specific integrated circuit (ASIC) adapted to monitor data bandwidth utilization and determine a level of forward error encoding to be used based on data bandwidth utilization.
• forward error encoder 206 can be implemented as an ASIC adapted to determine a level of forward error encoding based on signals received from bandwidth monitor 204.
• Figure 3 is a block diagram of a forward error encoder 300, which can be used to implement forward error encoder 206 shown in Figure 2.
• forward error encoder 300 includes an input/output interface 302, which functions primarily to receive signals from bandwidth monitor 204 and buffer 202 shown in Figure 2.
• Forward error encoder 300 also includes at least one processing unit 304, which functions primarily to execute computer-readable code for dynamically adjusting the level of forward error encoding according to signals received from bandwidth monitor 204 in Figure 2.
• Processing unit 304 includes interfaces with hardware components and circuitry that support the dynamic allocation of forward error encoding as described above.
• these hardware components include one or more microprocessors, memories, storage devices, interface cards, and other standard components known in the art.
• processing unit 304 functions with software programs, firmware or executable computer-readable code for carrying out various methods, process tasks, calculations, control functions, used in the dynamic allocation of forward error encoding as described above.
• the executable computer-readable code, firmware and software programs are tangibly embodied in any appropriate medium used for storage of computer-readable code including, but not limited to, all forms of non-volatile memory, including, by way of example and not by limitation, semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and DVD disks. Any of the foregoing may be supplemented by, or incorporated in, specially-designed application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs).
• ASICs application-specific integrated circuits
• FPGAs field programmable gate arrays
• processing unit 304 receives a signal from buffer 202 and bandwidth monitor 204 ( Figure 2).
• Processing unit 304 processes the signal from bandwidth monitor 204 according to executable computer-readable code stored on a computer readable medium.
• an executable computer-readable code causes processing unit 304 to select the level of forward error encoding to use based on data bandwidth utilized for data, as indicated by signals received from bandwidth monitor 204, such that the forward error encoding substantially occupies unutilized bandwidth.
• Processing unit 304 also calculates and generates the forward error encoding data based on the data received from buffer 202 ( Figure 2).
• processing unit 304 selects a default level of forward error encoding when bandwidth utilization for data is greater than a predetermined threshold value. Processing unit 304 then sets the threshold value at a value substantially equal to the maximum amount of bandwidth for data that allows sufficient bandwidth for a minimum level of forward error encoding in a worse case bandwidth scenario. In an alternative embodiment, processing unit 304 does not select a default level of forward error encoding.
• FIG 4 is a flowchart showing a method 400 of dynamically allocating forward error encoding according to a preferred embodiment of the present invention.
• a data formatting unit e.g., data formatting unit 108 in Figure 1
• monitors bandwidth utilization For this example embodiment, a bandwidth monitor (e.g., bandwidth monitor 204 in Figure 2) in the data formatting unit monitors data in a transmission buffer (e.g., transmission buffer 202 in Figure 2) to determine the amount of data being transferred at a given time.
• the data formatting unit determines if the bandwidth utilization for data is greater than a predetermined threshold value. For example, the bandwidth monitor determines if the threshold value has been exceeded.
• a forward error encoder uses a default level of forward error encoding at step 406.
• the default level is the minimum level necessary for successful data transmission in a worst case bandwidth scenario.
• the threshold value is the maximum amount of bandwidth that provides enough bandwidth for the default level of forward error encoding.
• different default levels and threshold values can be used.
• the bandwidth monitor indicates to what level the forward error encoder is to adjust the level of forward error encoding such that forward error encoding substantially occupies available bandwidth not being utilized for data.
• the forward error encoder can determine what level to adjust the forward error encoding. As bandwidth utilization for data increases, the level of forward error encoding decreases and vice versa. For example, if the threshold value is set at the maximum data bandwidth that allows the default level of forward error encoding, then excess unutilized bandwidth between the amount of bandwidth utilized for data and the threshold value is used for forward error encoding.
• the data formatting unit formats the data and forward error encoding for data transfer.
• the data formatting unit formats the data in a packet for transfer in a packet-switched network.
• the data formatting unit can format the data in another format, such as cells for transfer in a cell relay protocol.
• a transmitter e.g., transmitter 110 in Figure 1 transmits the formatted data and forward error encoding to a receiver (e.g., receiver 112).
• the transmitter is adapted to transmit the data over a wireless radio communication link.
• the transmitter is adapted to transmit the data over another type of communication medium, such as a wireline, coaxial cable or fiber optic cable.
• a receiver receives the transmitted data and detects the adjustments in forward error encoding.
• the receiver can detect the adjustments automatically.
• the transmitted forward error encoding contains one or more bits that indicate to the receiver what level of forward error encoding is being used.
• the receiver uses the forward error encoding to correct errors in the data transmitted.
• bandwidth monitoring occurs continuously and substantially simultaneously as other steps, such as transmitting formatted data.
• a threshold value and default level of forward error encoding are not used. In such embodiments, the level of forward error encoding is determined based on the bandwidth utilization for data.

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• Engineering & Computer Science (AREA)
• Quality & Reliability (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Detection And Prevention Of Errors In Transmission (AREA)

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• 2006
  • 2006-02-27 US US11/363,973 patent/US20070220403A1/en not_active Abandoned
• 2007
  • 2007-02-26 WO PCT/US2007/062781 patent/WO2007101145A1/en not_active Ceased
  • 2007-02-26 JP JP2008557455A patent/JP2009528790A/ja active Pending
  • 2007-02-26 EP EP07757460A patent/EP1989808A1/en not_active Withdrawn

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