4715 results about "Bit error rate" patented technology

A method for making a laser driver circuit for burst mode is described. The method includes the following steps: First, a continuous mode laser driver circuit is selected, the chip having a temperature compensation output, a bias current setting input, and a reference current setting input. Next, the temperature compensation signal is converted to a reference current setting signal via a first bias adjustment circuit, and the reference current setting signal is input to the reference current setting input. Then, the bias current setting input is connected to ground via a second bias adjustment circuit. The reference current setting signal automatically adjusts the high level and the low level of the eye diagram of the laser according to the environmental temperature, so that the high level and the low level are kept stable to reduce the bit error rate in transmission.

Component malfunctions in passive optical networks (PON) can increase bit error rates and decrease signal-to-noise ratio of communications signals. These faults may cause the receivers of the signals, either the optical line terminal (OLT) or optical network terminals (ONTs), to experience intermittent faults and / or may result in misinterpreted commands that disrupt other ONT's communication, resulting in a rogue ONT condition. Existing PON protocol detection methods may not detect these types of malfunctions. An embodiment of the present invention identifies faults in a PON by transmitting a test series of data patterns via an optical communications path from a first optical network node to a second optical network node. The test series is compared to an expected series of data patterns. An error rate may be calculated as a function of the differences between the test series and expected series. The error rate may be reported to identify faults in the PON. Through use of the embodiment, network faults can be identified and optionally automatically corrected, saving a network service provider from expending technician time and maintaining an operating state of the network.

A precoded orthogonal frequency division multiplexer (OFDM) system that improves the preformance of OFDM systems for spectral null channels, and size K×1 vector OFDM systems that reduce the cyclic prefix length by K times compared to conventional OFDM systems. The precoding scheme comprises inserting one or more zeros between each of the two sets of K consecutive information symbols, although it can be generalized to a general form. This precoding scheme removes the spectral nulls of an ISI channel without knowing the ISI channel. When no zero is inserts between each of the two sets of K consecutive information symbols and only K consecutive symbols are blocked together, vector OFDM systems are obtained. The bit error rate performance of the vector OFDM systems of the present invention is much improved over conventional OFDM systems.

Briefly, the present invention provides a dynamic channel re-assignment capability between mobile units, base stations and sectors within base station coverage areas. The wireless devices used in the present invention may include impulse radio communication devices such as, for example ultra-wideband radio (also known as digital pulse wireless) communication devices. Ultra-wideband bandwidth and channel allocation can be effectively managed, even though link quality generally deteriorates near the outer boundary of the base station. By maintaining dual communications with an adjoining base station, the present invention reduces the bit error rate and maintains signal strength (e.g., RF signal strength). This procedure is termed a “soft-handoff”.

Transmitters, receivers, and coding schemes to increase data rate and decrease bit error rate of an optical data link are disclosed. Data is transmitted across the link with a less than nominal bit error rate (BER), by encoding the data using a forward error correction (FEC) code or by requesting retransmission of transmitted packets in error. Data is transmitted at a speed that introduces errors at a rate that is in excess of the nominal BER but that may be corrected using the FEC code or retransmission so that the data may be received with less than the nominal BER. The data rate is increased as the link operating speed is increased beyond the overhead required by the FEC codes or retransmission. High speed FEC encoders and decoders facilitating such transmission are disclosed.

A solid-state mass storage device and method of anticipating a failure of the mass storage device resulting from a memory device of the mass storage device reaching a write endurance limit. A procedure is then initiated to back up data to a second mass storage device prior to failure. The method includes assigning at least a first memory block of the memory device as a wear indicator, using other memory blocks of the memory device as data blocks for data storage, performing program / erase (P / E) cycles and wear leveling on the data blocks, subjecting the wear indicator to more P / E cycles than the data blocks, performing integrity checks and monitoring the bit error rate of the wear indicator, and taking corrective action if the bit error rate increases, including the initiation of the backup procedure and generating a request to replace the device.

A smart memory system preferably includes a memory including one or more memory chips, and a processor including one or more memory processor chips. The system may include a smart memory controller capable of performing a bit error rate built-in self test. The smart memory control may include bit error rate controller logic configured to control the bit error rate built-in self test. A write error rate test pattern generator may generate a write error test pattern for the bit error rate built-in self test. A read error rate test pattern generator may generate a read error test pattern for the built-in self test. The smart memory controller may internally generate an error rate timing pattern, perform built-in self test, measure the resulting error rate, automatically adjust one or more test parameters based on the measured error rate, and repeat the built-in self test using the adjusted parameters.

Systems and methods are disclosed for remapping codewords for storage in a non-volatile memory, such as flash memory. In some embodiments, a controller that manages the non-volatile memory may prepare codeword using a suitable error correcting code. The controller can store a first portion of the codeword in a lower page of the non-volatile memory may store a second portion of the codeword in an upper page of the non-volatile memory. Because upper and lower pages may have different resiliencies to error-causing phenomena, remapping codewords in this manner may even out the bit error rates of the codewords (which would otherwise have a more bimodal distribution).

Memory cells are programmed and read, at least M=3 data bits per cell, according to a valid nonserial physical bit ordering with reference to a logical bit ordering. The logical bit ordering is chosen to give a more even distribution of error probabilities of the bits, relative to the probability distributions of the data error and the cell state transition error, than would be provided by the physical bit ordering alone. Preferably, both bit orderings have 2M−1 transitions. Preferably, the logical bit ordering is evenly distributed. The translation between the bit orderings is done by software or hardware.

Apparatus and methods provide relatively low uncorrectable bit error rates, low write amplification, long life, fast and efficient retrieval, and efficient storage density such that a solid-state drive (SSD) can be implemented using relatively inexpensive MLC Flash for an enterprise storage application. A page is associated with a set of primary ECC codewords, and a page stripe is associated with a set of secondary codewords and primary over secondary parity (PoSP) ECC codewords. Two or more page stripes can form a page grid, wherein the page grid is associated with a group of tertiary ECC codewords, wherein the last page stripe of the page grid has a reduced payload capacity.

Various read level control apparatuses and methods are provided. In various embodiments, the read level control apparatuses may include an error control code (ECC) decoding unit for ECC decoding data read from a storage unit, and a monitoring unit for monitoring a bit error rate (BER) based on the ECC decoded data and the read data. The apparatus may additionally include an error determination unit for determining an error rate of the read data based on the monitored BER, and a level control unit for controlling a read level of the storage unit based on the error rate.

Systems and methods that provide channel-adaptive antenna selection in multi-antenna-element communication systems are provided. In one embodiment, a method that selects a subset of receive antennas of a receiver to receive a transmitted RF signal may include, for example, one or more of the following: establishing possible subsets of the receive antennas; determining sets of channel parameter statistics corresponding to the possible subsets of the receive antennas; computing output bit error rates of the receiver, each output bit error rate being computed based on at least one set of channel parameter statistics; selecting a particular possible subset of the receive antennas based upon a criterion predicated on the computed output bit error rates; and connecting one or more RF chains of the receiver to the receive antennas of the selected particular possible subset.

A method and system is described for more optimally managing the usage of a wideband space-time multipath channel. The wideband space-time multipath channel is decomposed into a plurality of orthogonal sub-channels, where the orthogonal sub-channels having the best signaling characteristics are used for transmitting one or more signal streams. For purposes of decomposing the wideband space-time multipath channel into a plurality of orthogonal sub-channels, channel estimates are determined for each signal propagation path. A closed-form singular value decomposition of the channel corresponding to each receive antenna before coherent combining is utilized to obtain an orthogonal decomposition of the overall effective space-time channel after coherent combining. By using the overall effective space-time channel after coherent combining rather than before coherent combining, the complexity and correspondingly the resources required for obtaining the orthogonal sub-channels is significantly reduced. The method and system further provide for transmit power to be allocated between the selected sub-channels in order to minimize the effective bit-error rate for a fixed average throughput or to maximize average throughput for a fixed minimum effective bit-error rate.

In an SSD controller reading from flash memory, subsequent to failure of an initial soft-decision decoding attempt based on a nominal LLR, soft-decision re-decoding attempts are made using compensated LLR soft-decision information sets, pre-calculated at respective read-equilibrium points corresponding to mean shifts and variance change in the actual charge-state distributions of the flash memory channel. According to embodiment, soft-decision re-decoding attempts are performed without a retry read, or overlapped with one or more retry reads. By overlapping re-decoding with one or more retry reads, the probability of successful decoding increases, the need for further retry reads diminishes, and throughput is improved. The LLR compensation becomes very effective over a large number of retry reads, improving decoding reliability and achieving close to optimal bit error rates, even in the presence of large channel variation.

A method for testing a semiconductor device with a multi-gigabit communications receiver includes combining a data output from a high-speed communications transmitter with a perturbation signal generated by automatic test equipment. The combined signal data signal including jitter and low voltage swings is input to the communications receiver port under test. The automatic test equipment determines the bit error rate of the parallel data output from the receiver port under test. This test method is appropriate for semiconductor devices with multiple transceiver ports.

A system, computer readable program, and method for programming flash memory, the method includes: providing multiple pairs of most significant bit (MSB) page uncoded bit error rates (UBERs) and least significant bit (LSB) page UBERs; selecting a selected MSB page code rate and a selected LSB page code rate so that a selected MSB page UBER associated with the selected MSB page code rate and a selected LSB page UBER associated with the selected LSB page code rate support a highest average UBER out of the multiple pairs of MSB page UBERs and LSB page UBERs, wherein the selected MSB page code rate and the selected LSB page code rate are obtainable under a desired code rate constraint; and determining an encoding and programming scheme that may be based on the selected MSB page UBER, the selected MSB code rate, the selected LSB page UBER and the selected LSB code rate.

A bidirectional signal processing method uses parallel transmission of digital transmitted data streams in a multiple input-multiple output system. Related art methods generate high bit error rates mostly in singular transmission channels. For this reason, the rank-adaptive signal processing method provides that the number nd of active subchannels are varied according to the actual channel behavior in order to effect a robust data transmission even in singular radio channels based on a transmit-side and receive-side channel knowledge and a modification of the data vector by a linear matrix vector multiplication while introducing a factor gamma for limiting the maximum transmit power. The maximum transmit power is then only distributed to the currently activated subchannels so that no transmit power remains unused. Another optimization of the number of subchannels nd occurs when selecting the modulation and encoding methods. During the optimal rank-adaptation according to the water-filling principle, another power is allocated to each subchannel. Another modulation and encoding method is accordingly selected for each data stream. During the suboptimal rank-adaptation according to the channel inversion principle, all subchannels have the same power whereby enabling the data streams to be modulated and encoded in a common source

An average signal point amplitude detection section 15A determines an average position of I and Q components when a received QPSK modulated signal is demodulated and a threshold calculation section 15B determines threshold ths on an IQ plane based on the average signal point position of the received QPSK modulated signal and a theoretical distribution position on the IQ plane of signal points of a 16-value QAM signal. Then, a threshold decision section 14A makes a threshold-decision on the I and Q components of sequentially received QPSK modulated signals using this threshold ths and thereby calculates a simulated bit error rate of the 16-value QAM signal.

A system, method and apparatus for the wireless delivery of analog media from a media sink to a media source. The system, method and apparatus receives analog video and / or analog audio from the media source in respective native formats. The system, method and apparatus converts the received analog video and / or analog audio from respective native formats to a transmission format. The received analog video and / or analog audio is further processed for transmission over a wireless channel. The system, method and apparatus receives and processes the transmitted signal to produce recovered analog video and / or analog audio information. The recovered analog video and / or analog audio information is converted from the transmission format back to the respective native formats for delivery to the media sink. The system, method and apparatus provides a high data rate, low power wireless signal to the media sink at a low bit error rate.

A system and method for generating transmit weighting values for signal weighting that may be used in various transmitter and receiver structures is disclosed herein. The weighting values are determined as a function of frequency based upon a state of a communication channel and the transmission mode of the signal. In variations, weighting of the weighted signal that is transmitted through each of a plurality of antennas is carried out with one of a corresponding plurality of transmit antenna spatial weights. In these variations, a search may be conducted over various combinations of transmit weighting values and transmit antenna spatial weights in order to find a weight combination that optimizes a performance measure such as the output signal-to-noise ratio, the output bit error rate or the output packet error rate.

An apparatus (135), method and computer program are provided for determining and indicating a quality of a signal received by a first wireless communication device (105) from a second wireless communication device (110). In one embodiment, the apparatus (135) includes a bit-error-rate (BER) circuit (215) for measuring a BER of the signal, a comparator (145) for comparing the BER with a predetermined value to determine a relative signal quality, and an indicator (160) for indicating the quality of the signal to a user of the first device (105). Alternatively, the apparatus (135) includes a circuit for measuring the strength of the signal (230), a calculator (235) for calculating a signal-to-noise ratio (SNR) of the signal using the strength of the signal and a predetermined noise value, and a comparator (145) for comparing the SNR with a predetermined value to determine a relative signal quality. Signal quality is indicated by activating a number of characters (210) corresponding to the relative signal quality.

A transceiver module having integrated eye diagram opening functionality for reducing jitter is described. The transceiver module may include a transmitter eye opener and a receiver eye opener integrated in a single circuit. The transceiver module may also include serial control and various other integrated components. Other functionalities that may be integrated on the transceiver module include loopback modes, bypass features, bit error rate testing, and power down modes.

LDPC (Low Density Parity Check) coding and interleaving implemented in multiple-input-multiple-output (MIMO) communication systems. Initially, a novel approach is presented by which a wide variety of irregular LDPC codes may be generated using GRS or RS codes. These irregular LDPC codes can provide better overall performance than regular LDPC codes in terms of providing for lower BER (Bit Error Rate) as a function of SNR (Signal to Noise Ratio). A variety of communication device types are also presented that may employ the error correcting coding using a GRS-based irregular LDPC code, along with appropriately selected interleaving, to provide for even better performance. These communication devices may be implemented to in wireless communication systems including those that comply with the recommendation practices and standards being developed by the IEEE 802.11n Task Group (i.e., the Task Group that is working to develop a standard for 802.11 TGn (High Throughput)).

A method of delivering programming to passenger seats with a wireless in-flight entertainment system in an aircraft cabin uses a configurable cabin antenna system. Control data and programming is delivered with a head end server and received with one or more access points connected to the head end server. One or more antenna systems, connected to the access points, are disposed at optimum selected locations in the aircraft cabin to provide the programming to the passengers. One or more personal electronic devices (PEDs) located receive the programming from the one or more configurable antennas. Beams of the one or more antenna systems are adjusted to deliver programming to the one or more PEDs at a required bit error rate.

An integrated maximum a posteriori equalization and turbo product coding (IMAP-TPC) system for optical fiber communications systems (OFCS) is provided that uses probabilistic characterization of the electrical current in the presence of inter-symbol interference (ISI) and noise to compensate their effects and improve the bit error rate. In the IMAP-TPC system, turbo product code (TPC) decoding is integrated with a symbol-by-symbol maximum a posteriori (MAP) detector. The MAP detector calculates the log-likelihood ratio of a received symbol using the conditional electrical probability density information, and hence obtains a much more accurate reliability measure than the traditional measure used in the TPC decoder.

An adaptive quality control loop for link rate adaptation based on modulation and / or coding schemes (also referred to as "MCS levels") and one or more spreading codes that adaptively selects channel condition thresholds in real-time without measuring all the factors that affect selecting optimal channel condition thresholds. The adaptive quality control loop involves adjusting the channel condition thresholds with variable up and down steps based on target quality metrics along with measurements such as error detection results, relative frequencies of visiting each MCS level, and transmitted data rates, wherein the target quality metrics can be a block error rate or bit error rate target criterion. If the target quality metric is a block error rate target criterion, the variable step is determined using a desired MCS error rate based on MCS probabilities, MCS error rates and the block error rate target criterion. If the target quality metric is a bit error rate target criterion, the variable step is determined using a desired MCS error rate based on MCS probabilities, MCS error rates, average rate of bit errors, data rate, and the bit error rate target criterion.

A public safety communications network uses asymmetric channels for receiving requests for data from a mobile client over a narrowband land mobile radio system (LMRS) channel and delivering wideband data over a digital television (DTV) network channel to a DTV datacast receiver with the mobile client. An emergency operations center connected to the LMRS receives and processes the data requests and forwards the requested data. DTV network stations have a data multiplex insertion system for inserting the requested data into a DTV signal. The DTV network may be a public television network. An addressing system identifies unique mobile client addresses and unique mobile client group addresses and selects a DTV transmitter for delivering response messages in accordance with the addresses. A forward error correction (FEC) regulation system is used in transmitting requested data with FEC strength regulated as a function of historical bit-error-rate or receive power for a geographical location.

A signal weighting and combining method implemented within a receiver having a plurality of receive antennas is disclosed herein. Each receive antenna is disposed to produce a received RF signal in response to a transmitted RF signal received through a channel. The method includes weighting the plurality of received RF signals produced by the antennas in accordance with a corresponding plurality of RF weighting values selected to minimize an output bit error rate of the receiver, thereby forming a plurality of weighted RF signals. The method further includes combining ones of the plurality of weighted RF signals in order to form one or more combined RF signals. A similar splitting and weighting method capable of being implemented within a transmitter having a plurality of transmit antennas is also disclosed.