Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.