Itron Gmbh

Danny Ray Seely

Michael David McNamee

Keith W Barnes

Thomas F Uhling

Michael David Mcnamee

Jeffrey Steele Sanders

Junsong Lin

Techniques for managing message transmission using forward error correction include determining, by a communication application executing on a first node device based on one or more consecutive attempts to transmit messages to a second node device without using forward error correction (FEC) being unsuccessful, to use FEC to transmit messages to the second node device; and transmitting, by the communication application in response to determining to use FEC to transmit messages to the second node device, a first message to the second node device using FEC.

Management of message transmission using forward error correction

Various embodiments disclosed herein provide techniques for deciding when to use FEC to transmit a message between node devices in a mesh network. In various embodiments, a method includes receiving, by a communication application executing on a first node of a mesh network, a message; determining, by the communication application, a second node in the mesh network to transmit the message to, the second node being a neighbor of the first node; determining, by the communication application based on a history of forward error correction (FEC) and non-FEC transmissions with the second node, that FEC or non-FEC should be used to transmit the message; and transmitting, by the communication application, in response to determining that FEC or non-FEC should be used to transmit the message, the message to the second node using FEC or non-FEC.

Within a radio, a broadband digitizer is configured for channel assessment. In an example, a radio band is digitized to form a data stream. The data stream is channelized to form first and second in-phase in-quadrature (I/Q) sample streams. The first and second I/Q sample streams are provided to first and second channel assessors, respectively. Additionally, the first and second I/Q sample streams are bifurcated, to thereby provide the same first and second I/Q streams to first and second channel decoders, respectively. Accordingly, same portions of the first and second I/Q sample streams are presented to the first and second channel assessors and the first and second decoders, respectively, at the same time. Based at least in part on the channel assessments made by the channel assessors, a channel plan with less radio frequency noise may be selected.

Broadband digitizer used for channel assessment

Channel plan management enables a radio to select preferred channels within a potentially noisy radio frequency (RF) spectrum. In an example of RF spectrum analysis and channel plan management, a channel assessment tool analyzes RF spectrum, builds and maintains a database that include RF spectrum and/or channel information. In an example, a channel assessment tool (CAT) manager periodically collects the data from packet error rate (PER) estimators and resets them for a new collection interval. The CAT manager builds a statistical database for all channels. This database is used to identify the best channels over that collection period, which is then ultimately used to build a new channel plan. The CAT statistical database to generate a new active channel plan which is ultimately updated across many or all devices within a radio network.

Channel plan management in a radio network

A packet error rate estimator is configured to estimate packet error rate (PER). In an example, power or energy is calculated in one or more streams of I/Q samples over a period of time. The power or energy may be calculated for periods of time, e.g., bit-length periods of time, and a maximum value of bit-length power or energy may be selected over a packet-length period of time. The maximum power or energy associated with each stream of I/Q samples over the period of time may be compared to at least two threshold values. Each threshold value may be associated with an expected PER. Based at least in part on the comparing, and which of a plurality of threshold vales were (or were not) exceeded, a PER may be estimated for each stream of I/Q samples. The PER may be used to select a channel plan with less radio frequency noise.

Packet error rate estimator for a radio

In a radio using a plurality of channels defined in a radio frequency (RF) spectrum, a rate of false packet detections may be calculated for each of the plurality of channels using a plurality of respective correlation thresholds. The rate of false packet detections for each channel may be compared to a range of acceptable rates of false packet detections. The same or different ranges of acceptable rates of false packet detections may be used for each channel or each channel plan. Different correlation thresholds may be adjusted based at least in part on the comparisons. For example, if a rate of false packet detections exceeds a range of acceptable rates of false packet detections, the correlation threshold may be raised, or the reverse. A packet may be detected on different channels based on different adjusted correlation thresholds.

Radio with dynamically controlled correlation threshold

An example method of receiving a data packet includes receiving a data packet at a channel receiver of at least one channel receiver each associated with a channel, providing the data packet to a data packet identification block that corresponds to the channel receiver, validating the data packet at the data packet identification block, and providing the validated data packet to an available decoder block of at least one decoder block capable of performing one or more decoding functions, where a quantity of the decoder blocks is less than a quantity of the data packet identification blocks and optimized according to one or more goals. If no decoder block is available and the validated data packet is a higher priority data packet, a decoder block processing a lower priority data packet may be forced to stop processing the lower priority data packet and process the higher priority data packet.

Multi-channel decoder architecture

A decoder for a modulation scheme is configured to operate close to the radio noise floor. A correlation value may be constantly updated, in an effort to match to a signature to a preamble of a packet. A low clamp value may act as a floor to which a calculated correlation value is set, if it is less than the low clamp value. If a correlation threshold is exceeded, then the correlation value is examined to determine it is a peak value. If the peak is found, power of the preamble is compared to a power threshold that is relative to the radio noise floor. If the power threshold is exceeded, positive correlation is detected. A channel optimizer is used to remove the frequency misalignment. This enables the use of a filter that is approximately equal to the occupied bandwidth of the incoming signal, further rejecting noise and interference.

FSK/MSK decoder

A multichannel radio receiver configured for real-time radio channel assessment is described herein. In one example, a radio frequency (RF) front end provides a frequency spectrum which is converted into a digitized spectrum. Within a digital subsystem, resources (e.g., software or a hardware device) may analyze channels or portions of spectrum within the digitized spectrum for a packet error rate (PER) at a plurality of power levels and a plurality of modulation schemes. The analysis may result a required received signal strength indicator (RSSI) that is needed to result in a particular read reliability requirement (RRR). Using the required RSSI, endpoints communicating with the multichannel radio may be associated with a channel(s), modulation scheme(s) and/or power level(s) that results in the RRR. The analysis may be performed by one or more resources operating in parallel and operating in the background to other communications between the endpoints and multichannel radio receiver.

Real-time radio spectrum assessment engine

A radio includes a radio frequency (RF) subsystem to process analog information. A digital subsystem receives input from the RF subsystem, and may include a frequency error estimator and a transmitter. The frequency error estimator may be configured to receive samples from the digital subsystem and to estimate a frequency misalignment, between transmitter and receiver, of each of a plurality of received signals in real time. The transmitter may be configured to transmit to each of a plurality of downstream endpoints on frequencies based in part on the respective estimated frequency misalignments. Such transmissions, at a frequencies expected by each of the downstream endpoints, allows the use of narrower receiver filters by those endpoints. In one example, the plurality of received signals may be received simultaneously and be associated with packets of a plurality of different channel plans, with different channel bandwidths and/or channel spacing, and different channel modulation schemes.

Radio to detect and compensate for frequency misalignment

A multichannel radio receiver may include a radio frequency (RF) subsystem and a digital subsystem. The digital subsystem may be configured to use an analog to digital converter (ADC) to sample input. A channelizer bank within the digital subsystem may include a plurality of channelizers. Each channelizer may receive and translate input into a plurality of channels, the channels having widths that are non-uniform and/or spacing (e.g., spacing center-to-center of adjacent channels) that is not regular. The translation may include re-sampling channels at a rate associated with a modulation scheme. A decoder bank may include a plurality of decoders operating in parallel, each to receive input from a channelizer and each associated with a particular modulation scheme. Thus, the multichannel radio may simultaneously receive on a plurality of channels of arbitrary location, arbitrary spacing and/or arbitrary bandwidth, wherein each channel is associated with one of a plurality of modulation schemes.

Radio to support channel plans of arbitrary width and/or spacing

A multichannel radio receiver may include a radio frequency (RF) subsystem and a digital subsystem. The RF subsystem may be configured to provide analog information associated with a radio band to an analog to digital converter (ADC). The ADC samples the analog input and sends digital output to the digital subsystem. The digital subsystem may be configured with one or more channelizers and one or more decoders. A channelizer within the digital subsystem may filter and re-sample the digital output to result in a channel plan having a desired bandwidth and a desired sample rate. The sample rate may be selected for compatibility with a decoder. The decoder may have design specifications based in part on a modulation scheme to be decoded. The design specifications may indicate the desired sample rate to be provided by the channelizer.

Radio to analog-to-digital sample rate decoupled from digital subsystem

A multichannel radio receiver is configured to define at least two channel plans, each channel plan having at least one channel. The channel plans may differ due to channel bandwidths, channel locations, channel number and/or channel spacings. At least a portion of a radio spectrum may be common to at least two of the channel plans. At least two decoders may operate simultaneously to decode different modulation schemes on each of the at least two channel plans. In one example, two channel plans overlap portions of the radio spectrum. Two different and complementary modulation schemes are used on the two channel plans, respectively. The complementary modulation schemes reject signals associated with the other. Accordingly, portions of the radio spectrum are used simultaneously by at least two channel plans and at least two modulation schemes, respectively.

Simultaneous reception of multiple modulation schemes

A radio may define a channel plan to include one or more channels, and each channel may include a plurality of overlapping filters. Each filter may overlap at least one other filter, such as by an expected bandwidth of an incoming signal. The overlapping filters may extend over a frequency range based in part on an expected frequency error of the incoming signal. Due in part to the overlapping nature of the filters, the incoming signal will be within at least one of the filters. Since only one of the filters must receive the incoming signal, the filters may be narrower than might otherwise be the case, particularly in an application that includes frequency error. Accordingly, the filters may be narrower than their respective channels, and therefore receive less noise and interference. This improves signal-to-noise and improves the quality of the link and range.

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Spokane Valley, WA, United States of America

Danny Ray Seely