Patent Description:
TV channel availability can vary across both space and time. As a result, transceivers communicating using the TVWS spectrum may have to hop between different frequencies. Moreover, the TVWS spectrum is not continuous and single channel capacity using TVWS may not be enough to allow for satisfactory communication between some types of devices, such as Internet of Things (IoT) devices. Additionally, TVWS is sensitive to interference when the signal is low, resulting in use of the TVWS mostly for broadband communication today. Relevant background art can be found in <CIT>, <CIT> and <CIT>.

A computerized method for television white space (TVWS) communication comprises configuring a multi-narrowband transceiver for communication within the TVWS frequency spectrum using a log periodic filter, wherein the log periodic filter comprises a plurality of filter elements each having a filter frequency increasing periodically in a same frequency increasing factor (K). Each filter of the plurality of filter elements is configured to filter out second harmonics in a defined frequency range. The computerized method further comprises determining a TVWS channel for the communication and switching to a filter element of the plurality of filter elements corresponding to the determined TVWS channel. The computerized method also includes at least one of transmitting and receiving over the TVWS channel using the filter element.

In the figures, the systems are illustrated as schematic drawings. The drawings may not be to scale.

The computing devices and methods described herein are configured to communicate using the television (TV) white space (TVWS) spectrum. With the disclosure, communication between endpoint devices (e.g., clients) and a corresponding base station for use in an edge Internet of Things (IoT) environment makes use of the TVWS spectrum without having the limitations typically introduced when communicating using the TVWS, in various examples.

The endpoint device includes a multi-narrowband radio configured within a Long Range (LoRa®) protocol or network, which is a low-power wide-area network (LPWAN) protocol that uses spread spectrum modulation techniques. While aspects of the disclosure are described with reference to LoRa®, the disclosure is operable with other forms of long range protocols or networks. For example, different long range protocols can be used that allow for communication over longer distances (e.g., ten kilometers or more). With the disclosure, a log periodic filter is configured for communication within the TVWS spectrum to allow for narrowband longer range transmissions having lower power consumption. As a result, devices that otherwise cannot be satisfactorily used for such environments (e.g., IoT devices) are configured to use the TVWS spectrum for longer range, higher capacity, lower power consumption communications (e.g., communication in remote locations).

For example, with the present disclosure, IoT devices are able to operate at the lower frequencies in the TVWS (within the UHF and VHF bands) and for longer range communications (e.g., tens of miles), while providing large amounts of bandwidth, which can be <NUM> megahertz (MHz) per TV channel in some configurations. As such, a single TVWS base station can support large-scale IoT at very long-range when configured according to the present disclosure.

<FIG> illustrates a system <NUM> in accordance with one example. The system <NUM> allows a plurality of clients <NUM>, such as IoT devices, to communicate with a cloud-based device <NUM> through a gateway <NUM>. For example, the clients <NUM> can be co-located (at least part of the time) and are configured to communicate locally over one or more local networks using the TVWS and ultimately can communicate with external devices, such as cloud-based devices <NUM>, via one or more external networks through the gateway <NUM>. In the illustrated example, the system <NUM> is configured as a TVWS network that allows for communication between, for example, IoT devices.

The gateway <NUM> includes a base station <NUM> and an edge device <NUM> in the illustrated example. The base station <NUM> is configured such that a plurality of multi-narrowband transceivers <NUM> (one is shown in <FIG>) are configured to communicate over the TVWS and use the long range communication protocol (e.g., LoRa® protocol) as described in more detail herein. For example, the base station is configured to have a working frequency from <NUM> to <NUM>, which covers most VHF and UHF TV channels, <NUM>, <NUM>/<NUM> ISM band (i.e., industrial, scientific, and medical band) and/or other licensed frequency bands. It should be noted that the transceivers are used in the base station <NUM> and the clients <NUM>, which allows for TVWS network communication. In one example, the communication and control ports include one or more of: universal asynchronous receiver/transmitter (UART), universal synchronous/asynchronous receiver/transmitter (USART), universal serial bus (USB), serial peripheral interface (SPI), and/or multiple general purpose input/output (GPIO).

The one or more multi-narrowband transceivers <NUM> are configured in some examples to operate using time division multiple access (TDMA) for each frequency if a single multi-narrowband transceiver <NUM> is used. If multiple multi-narrowband transceivers <NUM> are used, frequency division multiple access (FDMA) is used. The edge device <NUM> is configured to allow computer control and transfer of data from each transceiver to the cloud-based device <NUM>. It should be noted that a combination of TDMA and FDMA is used in some examples. In one example, hardware provides spectrum/interference sensing function as described in more detail herein. The one or more multi-narrowband transceivers <NUM> are configures as one or more sub-modules in some examples.

In an IoT environment, the edge device <NUM> performs processing at the "edge" of the network (e.g., within the gateway <NUM>). Thus, in one example, the processing for performing transmission is done by the gateway <NUM>. However, the edge device <NUM> or the computing to perform TVWS communication as described herein, in some examples, is performed (or partially performed) at any location near the gateway <NUM>, which is not necessarily within the gateway <NUM> (e.g., a local computing device connected to the gateway <NUM>). As such, the processing or partial processing to allow for TVWS transmission in these examples is performed outside of the gateway <NUM>.

The base station <NUM> includes a global positioning system (GPS) device that provides location information. As described in more detail herein, the location information is used when configuring communication between the devices. The base station <NUM> is powered using one or more power sources, such as a power over ethernet (PoE) power supply in some examples, or other suitable sources of power.

Similarly, each of the clients <NUM> includes one or more multi-narrowband transceivers <NUM>. The clients <NUM> also include an interface extension board and connect to different sensors (e.g., IoT type sensors) in some examples. It should be noted that power for each of the clients can be provided using a solar panel, a battery (e.g., direct current), or alternating current (AC) power, among others. The power source is selected in some examples based on the application or environment in which the client <NUM> operates.

Thus, devices in the system <NUM> are configured to form a TVWS IoT network in some examples. As illustrated in <FIG>, and described in more detail below, the multi-narrowband transceivers <NUM> are configured with long range communication technology (e.g., (LoRa®) to communicate over the TVWS spectrum, having global positioning system (GPS) functionality on board of one or more of the multi-narrowband transceivers <NUM>, as well as spectrum/interference sensing.

More particularly, as shown in <FIG>, the multi-narrowband transceiver <NUM> is configured as a multi-narrowband radio operating using a long range communication protocol (e.g., LoRa® protocol) and TVWS frequency spectrum. In one example, the multi-narrowband transceiver <NUM> is configured to operate in the <NUM> to <NUM> frequency band. However, different frequency bands and ranges are contemplated.

The multi-narrowband transceiver <NUM> includes a multiband transmitter <NUM> and a multiband receiver <NUM> that enable multi-narrowband communication over the TVWS frequency spectrum as described herein. A transmit/receive (T/R) switch <NUM> is connected to an antenna <NUM> to allow for transmission and reception using the multiband transmitter <NUM> and the multiband receiver <NUM>. That is, the T/R switch <NUM> is configured to selectively connect to one of the multiband transmitter <NUM> or the multiband receiver <NUM> to enable transmission or reception by the multi-narrowband transceiver <NUM>. Thus, in operation, the T/R switch <NUM> switches between transmit or receive, wherein multiple multiband transmitters <NUM> can transmit during a transmit time or slot (transmit-T) in examples where the multiband transmitters <NUM> are configured to operate in different frequency bands. Similarly, multiple multiband receivers <NUM> can receive during a receive time or slot (receive-R) in examples where the multiband receivers <NUM> are configured to operate in different frequency bands.

On the receive side (receive path), a low-noise amplifier (LNA) <NUM> is connected between the multiband receiver <NUM> and the T/R switch <NUM>. The LNA <NUM> is configured to amplify signals received by the antenna <NUM>, including reducing unwanted noise. For example, the LNA <NUM> is configured to operate according to noise reduction techniques in the radio transmission technology. In one example, the LNA <NUM> is configured to amplify a very low-power signal from the antenna <NUM> without significantly degrading its signal-to-noise ratio. That is, the LNA <NUM> increases the power of both the signal and the noise, while minimizing the additional noise. In operation, the LNA <NUM> is configured to provide signal matching using signal matching techniques in the radio technology. It should be noted that any suitable reception technique in the radio transmission technology can be used. Thus, in the receive path, the LNA <NUM> (e.g., wideband LNA) operates to compensate for the matching loss of the narrow-band input of the multiband receiver <NUM>. It should be noted that the LNA <NUM> is not used if the receiver input is wideband matched.

On the send side (transmit path), a log periodic filter <NUM> is connected between the multiband transmitter <NUM> and the T/R switch <NUM>. For example, the log periodic filter <NUM> is configured to suppress second harmonics (i.e., filter out second harmonics). With the present disclosure, suppression of the harmonics, particularly second harmonics, is performed using different filters. That is, different filters are used to filter out harmonics at different frequencies. An example of the log periodic filter <NUM> having a plurality of filters <NUM> is illustrated in <FIG>.

As shown in <FIG>, a plurality of filters <NUM> is connected between a first radio frequency (RF) switch <NUM> and a second RF switch <NUM>. The first and second RF switches <NUM>, <NUM> are configured to route signals through one of the filters <NUM> based on a frequency of the signal. That is, the first and second RF switches <NUM>, <NUM> define transmission paths for signals of different frequencies within the TVWS frequency spectrum to be filtered through one of the filters <NUM> to remove second harmonics. The first and second RF switches <NUM>, <NUM> are configured to operate using switching techniques in the RF switching technology.

In one example, and in operation, the multiband transmitter <NUM> and the multiband receiver <NUM> are configured using a long range communication protocol device (e.g., an SX1262 LoRa® transceiver or other long range low power transceiver) to communicate within a frequency range of <NUM> to <NUM>. As a result of the multiband transmitter <NUM> being low power, filtering is performed by the filters <NUM> to suppress the second harmonics. As described below, the configuration and number of filters <NUM> of the log periodic filter <NUM> is selected to maintain similar filter specifications, while reducing the number of filters <NUM> used, thereby reducing complexity and cost. Filtering is performed in various examples because receiver matching is narrowband and cannot work in such a wide spectrum without re-matching. Thus, the present disclosure provides multi-filters for switching, which in one example, has a filter frequency increasing periodically with a same frequency increasing factor (K).

In one implementation, the multi-narrowband transceiver <NUM> is configured with long range transmission and reception capabilities using the log periodic filter <NUM>. The filter frequencies of the filters <NUM> (defining filter elements) are calculated using the following example equations: <MAT> <MAT>
wherein N is the number of filters, K is a frequency increasing factor, and f<NUM> is the starting frequency of filter <NUM> (sub-band <NUM>). For the other frequencies, f<NUM> is the ending frequency of filter <NUM> (sub-band <NUM>) and starting frequency of filter <NUM> (sub-band <NUM>), and the ending frequency fn+<NUM> is the ending frequency of the band.

In various examples, K is the ratio of the ending frequency to the starting frequency of the sub-band (e.g., K = fi+<NUM>/ fi), wherein fi+<NUM> is the ending frequency of the sub-band i and fi is the starting frequency of the sub-band i. The present disclosure is operable with examples in which the spectrum may not be continuing, such as if a designer wants to just cover the TV band and not cover a licensed band, filter <NUM> can be removed. Further, as described in more detail herein, K (ending frequency / starting frequency) is the same for all filters <NUM>.

The value of K in some examples is determined by simulation. For example, K depends on the type of filter. When determining K, the following rule is used in one example: in the pass band of the filter, the filter has less attenuation, and in the stop band (the second harmonics and higher order harmonics located), the filter has attenuation configured to suppress harmonics. It should be noted that there are trade-offs among pass band attenuation (the lower the better), stop band attenuation (the higher the better), and cost.

In one case, for example, a suitable K is determined to be <NUM>. In some examples, K is determined as follows: using Eq. <NUM>, N, is calculated, which is N=<NUM> in this example. Then a value for N is set, for example, N=<NUM> (N must be an integer) and the value of N is inserted in Eq. <NUM> to calculate K, which is <NUM> in this example. K is used to calculate the ending frequency of each sub-band. The ending frequency is also the starting frequency of the next sub-band in a continuous spectrum. In the case that the spectrum is not continuous, then that portion of the spectrum is skipped. The filter and matching circuit are then optimized to make the harmonics meet Federal Communication Commission (FCC) requirements.

In one example, the log periodic filter <NUM> includes only five filters <NUM> (also referred to as filter elements), which was determined by simulation (e.g., to determine N and K) to be the optimized number of filters <NUM> for the TVWS frequency spectrum. In this configuration, N=<NUM> and K=<NUM>, with the five filters <NUM> operating in the following frequency ranges:.

It should be noted that in various examples, K is limited to be less than <NUM>. As should be recognized, for low-pass or bandpass filtering, the starting and ending frequencies are less than one octave band in order to filter out the second harmonics. That is, the wide spectrum is divided into sub-bands defined by the starting and ending frequency of each filter. With the sub-bands selected, in some examples, the filters are optimized to filter harmonics, particularly second harmonics, such as to meet FCC requirements.

The filters <NUM> in one example are low-pass filters (LPFs), such as a Butterworth-type filter or a Chebyshev-type filter. However, other types of filters can be used. For example, in some implementations, the filters <NUM> are bandpass filters (BPFs). In operation, software of firmware is programmed to control the switching to one of the filters <NUM> based on a detected signal frequency. That is, the appropriate filter <NUM> is selected based on a signal frequency to use the filter <NUM> to suppress the second harmonics (e.g., select one of Filters <NUM>-<NUM> based on the frequency of the signal). The operating frequency range of each of the filters <NUM> is thereby optimized to divide the frequency band to each filter <NUM> (e.g., each LPF), wherein all frequency bands have the same K factor and the number of filters is minimized.

Thus, the present disclosure enables narrowband transmissions operating in the TVWS frequency spectrum, with harmonic suppression techniques that allows for compliance with communication requirements (e.g., FCC requirements). The filtering techniques described herein allow for the use of long range (e.g., LoRa®) transceivers having power amplifiers with low linearity (to increase power-added efficiency (PAE), thereby reducing power consumption) in the TVWS frequency spectrum. The present disclosure allows for narrowband communication in the TVWS while suppressing harmonics, particularly second harmonics, unlike conventional low pass filters that cannot meet the suppression requirements for the TVWS frequency spectrum, including the <NUM>/<NUM> ISM band.

The multi-narrowband transceiver <NUM> also includes a microcontroller, illustrated as a microcontroller unit (MCU) <NUM>. The MCU <NUM> is configured to control operation of the multi-narrowband transceiver <NUM>, including communication within the multi-narrowband transceiver <NUM>. The multi-narrowband transceiver <NUM> also includes a GPS <NUM> to determine the location of the multi-narrowband transceiver <NUM>. The GPS <NUM> allows for the multi-narrowband transceiver <NUM> to operate within the TVWS frequency range. That is, GPS location information is needed for TVWS devices (e.g., an FCC requirement for TVWS devices).

With particular reference now to the base station <NUM> (shown in <FIG>), in one example, the base station <NUM> is a multi-transceiver base station. That is, the base station <NUM> is configured having multiple multi-narrowband transceivers <NUM> in one example. However, in some examples, the base station <NUM> includes a single multi-narrowband transceiver <NUM>.

<FIG> illustrates a multi-transceiver base station <NUM> that is embodied as the base station <NUM> in some examples. The multi-transceiver base station <NUM> includes a plurality of multi-narrowband transceivers <NUM> configured in a master-subordinate arrangement. In the illustrated example, a master multi-narrowband transceiver 200a and a plurality of subordinate multi-narrowband transceivers 200b (also known as slave multi-narrowband transceivers) are controlled to allow communication with a plurality of clients <NUM> within different frequency ranges of the TVWS frequency spectrum.

In the illustrated example, the multi-narrowband transceivers <NUM> are connected to a multiplexer <NUM> to allow multiplexing of the multiple signals from the multi-narrowband transceivers <NUM>. The multiplexer <NUM> is configured as an RF power combiner in one example, and/or an RF power splitter, depending on whether signal transmission or reception is occurring. That is, the multiplexer <NUM> is configured to receive an input signal and output multiple output signals with specific output phase and amplitude characteristics. For example, a single RF line is split into multiple lines and the power output is divided between the lines, and/or more than one feed line is combined into a single RF line, depending on whether the signal are being received or sent by the multi-narrowband transceivers <NUM>, respectively. In one example, the multiplexer <NUM> is configured as an RF combiner/splitter, wherein the multiplexer <NUM> operates as a combiner or splitter based on whether transmit operations or receive operations are being performed. It should be appreciated that the multiplexer <NUM> can be any type of RF multiplexer or analog type RF combiner/splitter, for example.

A power amplifier (PA) <NUM> and an LNA <NUM> are connected to the multiplexer <NUM>. The PA <NUM> and LNA <NUM> are configured to compensate for signal loss of the multiplexer <NUM>. That is, the PA <NUM> and LNA <NUM> are configured to compensate for signal loss as a result of RF power splitting or RF power dividing. As can be seen, a pair of T/R switches <NUM> are connected between the PA <NUM> and LNA <NUM> and the multiplexer <NUM> on one end and between the PA <NUM> and LNA <NUM> and an antenna <NUM> on the other end. That is, the T/R switches <NUM> enable selection of the PA <NUM> or LNA <NUM> based on whether signals are being transmitted or received by the multi-narrowband transceivers <NUM>.

In the illustrated example, a combiner, which is configured as a multi-carrier power amplifier <NUM>, is connected between the PA <NUM> and LNA <NUM>, the antenna <NUM>, and a signal generator <NUM>. As will be described in more detail below, the signal generator <NUM> with the multi-carrier power amplifier <NUM> allows for transmission and reception of the multiple signals at the same time using the multi-narrowband transceivers <NUM> that allows for spectrum/interference sensing. That is, the multi-carrier power amplifier <NUM> supports multiple air interfaces simultaneously on a frequency band. In operation, this allows for the communication of the base station <NUM> with a plurality of the clients <NUM> simultaneously or concurrently.

In one configuration, one input/output (I/O) of each of the multi-narrowband transceivers <NUM> are connected together. For example, a general-purpose input/output (GPIO) pin of each of the multi-narrowband transceivers <NUM> are connected together to allow communication there between. The interconnection of the multi-narrowband transceivers <NUM> is configured to allow synchronization of the operations of the multi-narrowband transceivers <NUM>. In one example, the interconnected GPIO pins of the multi-narrowband transceivers <NUM> are assigned for synchronization operations.

In the illustrated example, the multi-narrowband transceiver 200a is assigned as the master device and the multi-narrowband transceivers 200b are assigned as subordinate devices (also known as slave devices) to the multi-narrowband transceiver 200a. The multi-narrowband transceiver 200a is configured to send transmit and receive control signals to the multi-narrowband transceivers 200b, that is, to all of the subordinate multi-narrowband transceivers 200b to control simultaneous operation of the multi-narrowband transceivers <NUM> (e.g., simultaneous send operations of the multi-narrowband transceivers <NUM>). In one example, all of the multi-narrowband transceivers <NUM> are configured to transmit or receive, namely to performing transmission or reception operations, in the same time slot, which eliminates interference between the multi-narrowband transceivers <NUM>. It should be appreciated that in some examples, all of the transceivers 200a and 200b are subordinate devices controlled by a computer (e.g., the computer <NUM> shown in <FIG>) sends transmit and receive control signals to all of the transceivers 200a and 200b). In other examples, the computer <NUM> monitors the transmit and received status, and the transceivers 200a sends transmit and receive control signals to the transceivers 200b.

In operation, in one example, each of the multi-narrowband transceivers <NUM> is configured to operate using time-division multiple access (TDMA) with synchronization of transmit and receive operation through the interconnection of the GPIO pins. The synchronization operations are performed on the medium access control (MAC) level or layer in one example. Accordingly, the GPIO of the multi-narrowband transceiver 200a sends transmit or receive control signals to the multi-narrowband transceivers 200b such that all of the multi-narrowband transceivers <NUM> (master and subordinates) transmit or receive at the same time. In one implementation, the transmit/receive (TX/RX) signal is a digital <NUM> or <NUM> to indicate a transmit or receive operation. In response, the T/R switches <NUM> are switched to a corresponding transmit or receive position. Thus, the multi-narrowband transceiver 200a controls when the multi-narrowband transceivers 200b (as well as the multi-narrowband transceiver 200a) transmit or receive.

It should be appreciated that other control schemes for the master-subordinate relationship can be used. In another example, the TX/RX signal is an analog high/low signal, namely a high voltage signal (e.g., +5V) and a low voltage signal (e.g., +1V). With this control scheme, a high voltage signal indicates that the multi-narrowband transceivers 200b should switch to a transmit mode and the multi-narrowband transceivers 200b thereafter operate for transmission. The low voltage signal indicates that the multi-narrowband transceiver 200b should switch to a receive mode and the multi-narrowband transceivers 200b thereafter operate for reception (e.g., a listen mode).

In one example, each of the multi-narrowband transceivers <NUM> is enabled to operate at different frequencies, for example, within one of the five filter frequency ranges as described herein. In some examples, TDMA is used to further expand the capabilities of communication over a particular channel. That is, for a given channel (frequency), TDMA is used to accommodate more devices.

The control scheme also includes a reset capability in some examples. For example, a reset pin of the multi-narrowband transceivers <NUM> are connected to a GPIO pin of a controller or computer <NUM>. In this configuration, the computer <NUM> is enabled to control resetting of the multi-narrowband transceivers <NUM>. For example, when a reset operation of the multi-narrowband transceivers <NUM> is needed (e.g., resynchronization or fault condition), the computer <NUM> sends a signal to the reset pins of the multi-narrowband transceivers <NUM>. In one example, the reset signal resets all of the multi-narrowband transceivers <NUM>. In other examples, selective ones of the multi-narrowband transceivers <NUM> can be reset.

Additionally, the base station <NUM> includes a GPS device <NUM>. As discussed in more detail herein, the GPS device <NUM> allows for determining location information needed when communicating using the TVWS frequency spectrum. A USB hub <NUM> is configured to connect the computer <NUM> to the multi-narrowband transceivers <NUM> in the illustrated example. However, other connections can be used and are contemplated by the present disclosure. Power is provided using a PoE power supply <NUM>. However, other power supplies can be used and are contemplated by the present disclosure.

In some examples, the signal generator <NUM> is configured to enable spectrum/interference sensing, such as illustrated in <FIG>. The signal generator <NUM> is configured to generate signals that allow for spectrum sensing for cognitive radio (CR) to prevent interference (e.g., prevent interference to licensed users). The signal generator <NUM> allows for high sensitivity spectrum sensing technology that detects the spectrum/interference and evaluates the impact of the interference from licensed and/or unlicensed CR users at very low signal levels. It should be appreciated that this technique can also be used to search for a lowest interference channel in the ISM band.

The signal generator <NUM> allows for detection of the minimum detectable signal (MDS) of the TVWS narrowband transceiver, as low as -<NUM> dBm, with low power consumption, in one example. This detection is operable for communications in a long-range low data rate network, wherein the working channel can change with location and time. The spectrum sensing of the present disclosure can detect very low-level spectrum energy, as well as evaluate the impact of the interference to communication.

The signal generator <NUM> is configured as an internal signal generator that simulates the signal of a remote transmitter and uses the antenna <NUM> to pick up interference. With the herein described configuration, the sensitivity of the interference sensing is the same as the MDS of the transceiver, for example the multi-narrowband transceivers <NUM>, under the interference, and high impedance matching of the internal signal generator minimizes the impact to the antenna matching of the multi-narrowband transceivers <NUM>.

In some examples, channel searching can also be implemented, such as in firmware (e.g., to identify a channel with lower or least interference).

Specifically, and with particular reference to <FIG> and <FIG>, the multi-narrowband transceivers <NUM>, the antenna <NUM>, the multi-carrier power amplifier <NUM>, and signal generator <NUM> form a spectrum sensing system. It should be appreciated that the multi-carrier power amplifier <NUM>, in one example, is an RF Y connector that connects to the antenna <NUM>, the RF port of the multi-narrowband transceivers <NUM> and the signal generator <NUM>. The signal generator <NUM> has high-impedance output terminals that do not affect the antenna matching of the multi-narrowband transceivers <NUM>. In normal use of the multi-transceiver base station <NUM>, the signal generator <NUM> is inactive (turned off).

In one example, the signal generator <NUM> includes a transmitter <NUM> connected to a high impedance matching network <NUM> through an RF attenuator <NUM>. In operation, spectrum/interference sensing is performed as follows:.

Some of the operations above may be performed in parallel, and in a different order than shown. Further, it should be noted that the transmitter <NUM> is the same as the multiband transmitter <NUM> (shown in <FIG>) in some examples. However, any suitable transmitter can be used. Additionally, RF attenuation by the RF attenuator <NUM> can be controlled manually, by analog, or digitally. The high impedance matching network <NUM> (e.g., a resistor) reduces the effect of the signal generator <NUM> on antenna matching.

Thus, in operation, antenna pick up interference is combined with the signal from signal generator <NUM> and fed into the multi-narrowband transceivers <NUM>. The signal strength of the signal generator <NUM> is gradually reduced until the MDS under interference is obtained. The MDS under interference indicates the strength of the interference and the impact on the communication. Spectrum sensing as part of the TVWS IoT network can improve spectrum utilization and improve network stability and reliability.

Thus, the present disclosure allows devices, such as IoT devices, to operate within a TVWS network. For example, various examples described herein can be used in a cloud-backed IoT application. TVWS IoT implemented as described herein allows for a for large-scale IoT deployments (e.g., farming, oil field, gas fields, etc.) and can be backed by cloud and edge devices.

<FIG> is a flowchart of a method <NUM> illustrating operations of a computing device (e.g., client <NUM>) to communicate over a TVWS network. For example, the method <NUM> configures a transceiver to allow long range (e.g., LoRa®) communication using the TVWS frequency spectrum. It should be appreciated that the computing device is implementable in different systems and applications. Thus, while the below-described example can be used in connection with an IoT application, the computing device configured according to the present disclosure is useable, for example, in many different applications, including any application using narrowband communication over a TVWS network.

At <NUM>, a multi-narrowband transceiver is configured for communication within the TVWS frequency spectrum using a log periodic filter. For example, as described herein, the multi-narrowband transceiver <NUM> is configured with the log periodic filter <NUM> that allows for communication within various frequency ranges of the TVWS frequency spectrum. That is, the log periodic filter <NUM> includes a plurality of filter elements each optimized to communicate over a range of the TVWS frequency spectrum by using the same K value. The defined ranges for the filter elements are optimized to suppress second harmonics during transmission. In one example, the multi-narrowband transceiver <NUM> is configured to allow long range communication within the frequency ranges of the TVWS using the log periodic filter.

At <NUM>, a TVWS channel for communication is determined. For example, as described herein, spectrum/interference sensing can be performed to identify an unused channel within the TVWS frequency spectrum. In one example, based on the spectrum/interference sensing (or in some examples the location and known channel usage), an available TVWS frequency is selected having minimal interference. That is, the use of the channel does not interfere with usage by other entities.

At <NUM>, a filter element within the log periodic filter <NUM> corresponding to the TVWS channel is switched to for use in communication. That is, the filter element operating within a frequency range covering the frequency of the available TVWS frequency that is determined at <NUM> is activated to filter signals being communicated by the multi-narrowband transceiver <NUM>. In operation, the filter element filters out the second harmonics during transmission using the TVWS channel. In particular, transmission and reception of signals using the TVWS channel is performed at <NUM> with the signals filtered by the switched to filter element. As a result, optimized TVWS communication is provided in combination with a long communication protocol (e.g., using the LoRa® protocol). For example, devices are thereby configured for operation in a TVWS network.

<FIG> is a flowchart of a method <NUM> illustrating operations of a computing device (e.g., base station <NUM>) to communicate over a TVWS network with a plurality of devices (e.g., clients <NUM> or IoT devices). For example, the method <NUM> configures a base station to simultaneously or concurrently communicate with a plurality of devices using multiple frequencies of the TVWS frequency spectrum.

At <NUM>, at determination is made whether the base station or devices are ready to transmit. For example, a determination is made whether communication between a plurality of IoT devices through a base station is to be performed using the TVWS frequency spectrum. If transmission is not going to occur, then the base station is configured to perform listen operations, namely, to be in a receive mode. In this mode, a master transceiver of the base station (e.g., the multi-narrowband transceiver 200a of the base station <NUM>) sends a receive or listen control signal to a plurality of subordinate transceivers (e.g., the multi-narrowband transceiver 200b of the base station <NUM>) at <NUM>. For example, an analog signal (e.g., voltage high or low) or digital signal (e.g., <NUM> or <NUM>) is sent to each of the subordinate transceivers that are interconnected together and with the master transceiver as described herein (e.g., a GPIO pin). In this mode, all of the transceivers, including the master and subordinate transceivers, are enabled to receive in the same time slot.

If a determination is made that transmission is to occur, then the base station is configured to perform transmit operations, namely, to be in a transmit mode. In this mode, a master transceiver of the base station (e.g., the multi-narrowband transceiver 200a of the base station <NUM>) sends a transmit control signal to a plurality of subordinate transceivers (e.g., the multi-narrowband transceiver 200b of the base station <NUM>) at <NUM>. For example, an analog signal (e.g., voltage high or low) or digital signal (e.g., <NUM> or <NUM>) is sent to each of the subordinate transceivers that are interconnected together and with the master transceiver as described herein (e.g., a GPIO pin). It should be noted that the control signal for the transmit mode is opposite to the control signal for the listen or receive mode (e.g., low voltage instead of high voltage, or <NUM> instead of <NUM>). In this mode, all of the transceivers, including the master and subordinate transceivers, are enabled to transmit in the same time slot.

In the receive/listen and transmit modes, a multiplexer, which is configured as an RF combiner or divider is also controlled. In particular, one or more T/R switches (e.g., T/R switches <NUM>) are controlled to select transmit or receive operation via an antenna (e.g., the antenna <NUM>).

At <NUM>, a determination is made if transmission is complete. If transmission is not complete, transmission continues at <NUM>. If transmission is complete, interference sensing is performed at <NUM>. As described herein, a signal generator (e.g., the signal generator <NUM>) is configured to perform spectrum/interference sensing by generating an RF signal for use in determining the lowest RSSI, which identifies the MDS under interference. It should be noted that the signal generator is turned off during normal use (e.g., during transmission and reception).

At <NUM>, one or more available TVWS channels are determined from the interference sensing. For example, based on the RSSI (and/or SNR) determined at <NUM>, one or more TVWS channels are identified that are available for transmission (e.g., below a threshold interference level). The frequency of the available channels allows for the identification of filter elements in the transceivers to use for subsequent transmission at <NUM>. For example, filter elements optimized for long range communication over defined TVWS frequency ranges are identified and the filter element having the determined available channel frequency therein is identified. Thus, a multi-transceiver base station is configured to allow communications over different frequencies in the same time slot, which eliminates interference between the transceivers.

The present disclosure is operable with a computing apparatus <NUM> according to an example as a functional block diagram <NUM> in <FIG>, such as an IoT device. In one example, components of the computing apparatus <NUM> may be implemented as a part of an electronic device according to one or more examples described in this disclosure. The computing apparatus <NUM> comprises one or more processors <NUM> which may be microprocessors, controllers or any other suitable type of processors for processing computer executable instructions to control the operation of the computing apparatus <NUM>. Platform software comprising an operating system <NUM> or any other suitable platform software may be provided on the computing apparatus <NUM> to enable application software <NUM> to be executed on the computing apparatus <NUM>. According to an example, communication via a multi-narrowband transceiver <NUM>, such as implemented with an IoT client device, may be accomplished by software and/or hardware.

Computer executable instructions may be provided using any computer-readable media that are accessible by the computing apparatus <NUM>. Computer-readable media may include, for example, computer storage media such as a memory <NUM> and communications media. Computer storage media, such as the memory <NUM>, include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or the like. Computer storage media include, but are not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by a computing apparatus. In contrast, communication media may embody computer readable instructions, data structures, program modules, or the like in a modulated data signal, such as a carrier wave, or other transport mechanism. As defined herein, computer storage media do not include communication media. Therefore, a computer storage medium should not be interpreted to be a propagating signal per se. Propagated signals per se are not examples of computer storage media. Although the computer storage medium (the memory <NUM>) is shown within the computing apparatus <NUM>, it will be appreciated by a person skilled in the art, that the storage may be distributed or located remotely and accessed via a network or other communication link (e.g. using a communication module, such as a communication interface <NUM>).

The computing apparatus <NUM> in one example includes an input/output controller <NUM> configured to output information to one or more input devices <NUM> and output devices <NUM>, for example a display or a speaker, which may be separate from or integral to the electronic device. The input/output controller <NUM> in some examples is configured to receive and process an input from one or more input devices <NUM>, such as a control button or touchpad. In one example, the output device <NUM> acts as the input device <NUM>. An example of such a device may be a touch sensitive display. The input/output controller <NUM> in one example also outputs data to devices other than the output device <NUM>, e.g. a locally connected printing device. In some examples, a user provides input to the input device(s) <NUM> and/or receives output from the output device(s) <NUM>.

In one example, the computing apparatus <NUM> detects voice input, user gestures or other user actions and provides a natural user interface (NUI). This user input is used to author electronic ink, view content, select ink controls, play videos with electronic ink overlays and for other purposes. The input/output controller <NUM> outputs data to devices other than a display device in some examples, e.g. a locally connected printing device.

The functionality described herein can be performed, at least in part, by one or more hardware logic components. According to an example, the computing apparatus <NUM> is configured by the program code when executed by the processor(s) <NUM> to execute the example of the operations and functionality described. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Program-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), Graphics Processing Units (GPUs).

At least a portion of the functionality of the various elements in the figures may be performed by other elements in the figures, or an entity (e.g., processor, web service, server, application program, computing device, etc.) not shown in the figures. Additionally, in some aspects, the computing apparatus <NUM> is a lower power device (e.g., LoRa) having multi-narrowband communication capabilities over the TVWS frequency spectrum.

Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with aspects of the disclosure include, but are not limited to, mobile or portable computing devices (e.g., smartphones), personal computers, server computers, hand-held (e.g., tablet) or laptop devices, multiprocessor systems, gaming consoles or controllers, microprocessor-based systems, set top boxes, programmable consumer electronics, mobile telephones, mobile computing and/or communication devices in wearable or accessory form factors (e.g., watches, glasses, headsets, or earphones), network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. In general, the disclosure is operable with any device with processing capability such that it can execute instructions such as those described herein. Such systems or devices may accept input from the user in any way, including from input devices such as a keyboard or pointing device, via gesture input, proximity input (such as by hovering), and/or via voice input.

A device for TV white space (TVWS) communication comprises a multiband transmitter and a multiband receiver; an antenna, the multiband transmitter and the multiband receiver connected to the antenna and configured to transmit and receive at a plurality of TVWS frequencies; and a log periodic filter connected between the multiband transmitter and the antenna, the log periodic filter comprising a plurality of filter elements each having a filter frequency increasing periodically in a same frequency increasing factor (K), each filter of the plurality of filter elements configured to filter out second harmonics in a defined frequency range. The defined frequency range may include the TVWS spectrum, or another range such as <NUM>-<NUM> (which is more than the TVWS spectrum, and includes the land mobile radio (LMR) band and some ISM bands).

A base station for TV white space (TVWS) communication comprises a master transceiver; a plurality of subordinate transceivers, wherein the master transceiver and the plurality of subordinate transceivers are interconnected, the master transceiver and the plurality of subordinate transceivers configured to transmit and receive at a plurality of TVWS frequencies; an antenna connected to the master transceiver and the plurality of subordinate transceivers; an RF combiner/splitter connected between the antenna and the master transceiver and the plurality of subordinate transceivers; and a log periodic filter within the master transceiver and the plurality of subordinate transceivers, the log periodic filter comprising a plurality of filter elements each having a filter frequency increasing periodically in a same frequency increasing factor (K), each filter of the plurality of filter elements configured to filter out second harmonics in a defined frequency range.

A computerized method for TV white space (TVWS) communication comprises configuring a multi-narrowband transceiver for communication within the TVWS frequency spectrum using a log periodic filter, the log periodic filter comprising a plurality of filter elements each having a filter frequency increasing periodically in a same frequency increasing factor (K), each filter of the plurality of filter elements configured to filter out second harmonics in a defined frequency range within the TVWS frequency spectrum; determining a TVWS channel for the communication; switching to a filter element of the plurality of filter elements corresponding to the determined TVWS channel; and at least one of transmitting and receiving over the TVWS channel using the filter element.

A computerized method for interference sensing with a signal generator, the computerized method comprising:.

It will be understood that the benefits and advantages described above may relate to one example or may relate to several examples. The examples are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

The examples illustrated and described herein as well as examples not specifically described herein but within the scope of aspects of the claims constitute exemplary means for device communication using the TVWS spectrum.

In some examples, the operations illustrated in the figures may be implemented as software instructions encoded on a computer readable medium, in hardware programmed or designed to perform the operations, or both. For example, aspects of the disclosure may be implemented as a system on a chip or other circuitry including a plurality of interconnected, electrically conductive elements.

Claim 1:
A device for television white space, TVWS, communication, the device comprising:
a multiband transmitter (<NUM>) and a multiband receiver (<NUM>);
an antenna, the multiband transmitter (<NUM>) and the multiband receiver (<NUM>) connected to the antenna (<NUM>) and configured to transmit and receive at a plurality of TVWS frequencies; and
a log periodic filter (<NUM>) connected between the multiband transmitter (<NUM>) and the antenna (<NUM>), the log periodic filter (<NUM>) comprising a plurality of filter elements (<NUM>) each having a filter frequency increasing periodically in a same frequency increasing factor, each filter of the plurality of filter elements (<NUM>) configured to filter out second harmonics in a defined frequency range within a spectrum including TVWS.