Patent Description:
Current techniques for acquiring communications signals of different communication modes at a single receiver use mode switching (e.g., based on the IEEE <NUM>. <NUM> standard). Mode switching allows for a plurality of communication modes to be supported by a single receiver by utilizing a common initial communication mode. For example, as a part of a common initial communication mode between a transmitter and a receiver, a specific communication mode for the signals that are to be subsequently received is provided to the receiver. The receiver is then able to be switched or configured to receive the signals corresponding to that specific communication mode.

<CIT> describes a cell search method for a multi-mode telecommunication apparatus. The method comprises receiving signals present in a frequency range; transforming received signals into frequency domain; estimating power spectral density from transformed signals; estimating probability of different communication modes by correlating the estimated power spectral density with power spectral density signatures of said different communication modes; and performing cell search according to estimated most probable communication mode.

Although the use of a common initial communication mode can be effective for implementing a receiver that is capable of receiving signals of multiple modes, such a technique has limited applicability due to its strict requirements for common mode operation. Requiring that all initial communication occur using the same common mode is difficult or impossible to enforce, for example, when the signals being exchanged are associated with different communications standards (e.g., IEEE <NUM>, IEEE <NUM>, IEEE <NUM>, etc.). Additionally, requiring a common initial communication mode can also increase the computational resources required for multimode signal acquisition, as well as the power consumed by the receiver.

As such, the present disclosure provides cost-effective systems and methods for the acquisition of signals of different communication modes. The invention to which this European patent relates is defined in the appended claims.

According to an example which does not fall within the wording of the appended claims, disclosed herein is a system for transmitting and receiving signals over a network. The system includes a receiver that is configured for multimode signal acquisition. The receiver includes a filter module, a sampling module, a first analysis module, a second analysis module, and a classification module. The filter module is configured to filter a received signal and to generate a filtered signal. The sampling module is configured to sample the filtered signal and to generate a sampled signal. The first analysis module is configured to analyze at least one characteristic of the sampled signal associated with a first predetermined frequency. The first analysis module is also configured to generate a first output signal associated with the at least one characteristic. The second analysis module is configured to analyze the at least one characteristic of the sampled signal associated with a second predetermined frequency. The second analysis module is also configured to generate a second output signal associated with the at least one characteristic. The classification module is configured to classify the received signal into one of a plurality of different communication modes based on the first output from the first analysis module and the second output from the second analysis module.

According to another example which does not fall within the wording of the appended claims, also disclosed herein is a method of multimode signal acquisition in a receiver. The method includes receiving a communication signal associated with one of a plurality of different communication modes, sampling the communication signal to generate a sampled signal, and analyzing at least one characteristic of the sampled signal associated with a first predetermined frequency. A first output signal associated with the at least one characteristic is then generated. The method also includes analyzing the at least one characteristic of the sampled signal associated with a second predetermined frequency, generating a second output signal associated with the at least one characteristic, and classifying the received signal into one of the plurality of different communication modes based on the first output signal and the second output signal.

According to another example which does not fall within the wording of the appended claims, also disclosed herein is a device that is configured to process digital signals. The device includes a filter module, a sampling module, a first analysis module, a second analysis module, and a classification module. The filter module is configured to filter a received signal and to generate a filtered signal. The sampling module is configured to sample the filtered signal and to generate a sampled signal. The first analysis module is configured to analyze a spectral density of the sampled signal associated with a first predetermined frequency. The first analysis module is also configured to generate a first output signal associated with the spectral density for the first predetermined frequency. The second analysis module is configured to analyze the spectral density of the sampled signal associated with a second predetermined frequency. The second analysis module is also configured to generate a second output signal associated with the spectral density for the second predetermined frequency. The classification module is configured to classify the received signal into one of a plurality of different communication modes based on the first output from the first analysis module and the second output from the second analysis module.

According to another example which does not fall within the wording of the appended claims, also disclosed herein is a method of transmitting a plurality of signals of different communication modes to, and receiving the plurality of signals at, a receiver. The method includes transmitting a first signal from a first transmitter to the receiver. The first signal is transmitted according to a first communication mode. The method also includes transmitting a second signal from a second transmitter to the receiver. The second signal is transmitted according to a second communication mode, and the first communication mode is different than the second communication mode. The first signal and the second signal are transmitted to the receiver without a common initial communication mode.

Other examples will become apparent by consideration of the detailed description and accompanying drawings.

Embodiments of the invention relate to systems and methods for multimode signal acquisition within a network, such as a utility communications network. Such systems include, for example, multimode receivers that are configured to efficiently and effectively identify a communication mode for an incoming or received signal with reduced or limited computational (e.g., processing, memory, etc.) and power requirements. The multimode receivers can include, among other things, one or more analysis modules for analyzing a characteristic of a received signal (e.g., amplitude, power, power spectral density ["PSD"], etc.) or a portion of the received signal (e.g., a preamble or syncword, header, etc.). Such a multimode receiver can be configured to execute computer readable instructions corresponding to a process for determining or identifying a communication mode of the received signal. The process includes, among other things, receiving a signal (e.g., a modulated analog signal) from another device. The received signal may have been modulated using any of a variety of modulation and/or transmission techniques, such as amplitude shift keying ("ASK"), frequency shift keying ("FSK"), phase shift keying ("PSK"), quadrature amplitude modulation ("QAM"), binary FSK ("BFSK"), minimum FSK ("MSK"), multiple FSK ("MFSK"), differential PSK ("DPSK"), binary PSK ("BPSK"), quadrature PSK ("QPSK"), offset QPSK ("O-QPSK"), orthogonal frequency division multiplexing ("OFDM"), etc. The received analog signal is then filtered using an intermediate frequency ("IF") filter that shifts the frequency of the carrier signal to a lower frequency for processing and analysis.

Following analog-to-digital conversion, the signal is provided to one or more analysis modules which perform frequency analysis on the digital form of the received signal. The frequency analysis can be performed in a number of different ways (e.g., using a Goertzel algorithm). After the characteristics of the signals have been analyzed, the outputs of the analysis modules are provided to a classification module. The classification module compares, for example, a PSD for one or more frequencies of interest specific to the different communication modes to predetermined PSD values at the frequencies of interest for each of the communication modes. Based upon the comparisons of the PSD values for the various communication modes, the communication mode may be determined, and the multimode receiver can be configured for the full acquisition of signals transmitted according to the determined communication mode. As such, the communication mode can be determined without requiring additional information to be transmitted through the utility communications network. Additionally, because the communication mode can be determined based on a portion of the received signal (e.g., the preamble) at a relatively low frequency, the frequencies of interest for which analysis is performed can be well-defined and are within a relatively narrow band of frequencies.

<FIG> illustrates a generalized communications system <NUM> (e.g., a utility communications system or network) that includes a first back office system ("BOS") <NUM>, a second BOS <NUM>, a communications network <NUM>, a domain name system or server ("DNS") <NUM>, an access point <NUM>, a local network <NUM>, and nodes <NUM>-<NUM>. The nodes <NUM>-<NUM> communicate through the network <NUM>, such as a local area network ("LAN"), a neighborhood area network ("NAN"), a home area network ("HAN"), or personal area network ("PAN") using any of a variety of communications protocols, such as Wi-Fi, Bluetooth, ZigBee, etc. This network is, in turn, configured for communication with the access point <NUM>, which is also associated with the communications network <NUM>. The communications network <NUM> is, for example, a wide area network ("WAN") (e.g., a TCP/IP based network, a Global System for Mobile Communications ["GSM"] network, a General Packet Radio Service ["GPRS"] network, a Code Division Multiple Access ["CDMA"] network, an Evolution-Data Optimized ["EV-DO"] network, an Enhanced Data Rates for GSM Evolution ["EDGE"] network, a 3GSM network, a Digital Enhanced Cordless Telecommunications ["DECT"] network, a Digital AMPS ["IS-<NUM>/TDMA"] network, an Integrated Digital Enhanced Network ["iDEN"] network, a Digital Advanced Mobile Phone System ["D-AMPS"] network, etc.).

The connections between the nodes <NUM>-<NUM> and the network <NUM>, and the connections between the network <NUM> and the access point <NUM> are, for example, wired connections, wireless connections, or a combination of wireless and wired connections. In some embodiments, the nodes <NUM>-<NUM> communicate through the network <NUM> using wireless communications, and the first access point <NUM> communicates through the network <NUM> using a wired network connection.

In some embodiments, the networks described above are, for example, self-configuring or mobile ad hoc networks ("MANETs") which utilize a mesh network topology to provide redundancy to the communications system <NUM>. In other embodiments, the networks have different network topologies, such as ring, star, line, tree, bus, or fully-connected network topologies. In the illustrated embodiment, the networks and the communication between the devices associated with the networks can be protected using one or more encryption techniques, such as those techniques provided in the IEEE <NUM> standard for port-based network security, pre-shared key, Extensible Authentication Protocol ("EAP"), Wired Equivalency Privacy ("WEP"), Temporal Key Integrity Protocol ("TKIP"), Wi-Fi Protected Access ("WPA"), etc..

The DNS <NUM> connects to network <NUM> through the access point <NUM>. In other embodiments, the DNS <NUM> connects to the network <NUM> through the communications network <NUM> and then through the access point <NUM>. In some embodiments, the DNS <NUM> is capable of receiving and processing dynamic updates to provide a dynamic DNS ("DDNS") service. Messages sent from the BOSs <NUM> and <NUM> to the nodes <NUM>-<NUM> within the network <NUM> are sent by way of unique network addresses associated with the one or more nodes and registered with the DNS <NUM>. In some embodiments, the DNS <NUM> is dedicated to a single LAN, or is shared by a plurality of LANs. The DNS <NUM> maintains network addresses for the nodes <NUM>-<NUM> and the network <NUM>. The network addresses for the nodes <NUM>-<NUM> are stored or maintained in, for example, a node route registry. In some embodiments, the DNS <NUM> also maintains address allocation information, such as a node address allocation indicator or node preference indicator. The network registration and communication process for a node within a communications system, such as system <NUM>, is described in greater detail in <CIT>.

The first BOS <NUM> and the second BOS <NUM> are implemented as a single device, a combination of devices, a network management system, a server, one or more computers, one or more network devices, one or more communications devices, one or more software applications, or a variety of components that is/are capable of communicating with one or more of the access point <NUM> or nodes <NUM>-<NUM> via the communications network <NUM>. The first BOS <NUM> and the second BOS <NUM> are, for example, associated with one or more utility providers, credit card companies, other financial institutions, etc..

<FIG> illustrates a device <NUM> such as a node, an access point, a BOS, or another component or device of the communications system <NUM> that includes, among other things, a control unit or controller <NUM>, a first radio <NUM>, and a second radio <NUM>. The device <NUM> can be configured as a transmitter, a receiver, or both a transmitter and a receiver. The controller <NUM> includes, for example, a control or processing unit <NUM>, a memory <NUM>, an input/output ("I/O") module <NUM>, a power supply module <NUM>, and one or more busses for operably and communicatively coupling the components within the controller <NUM>. The processing unit <NUM> is, for example, a processor, a microprocessor, a microcontroller, etc. The memory <NUM> includes, for example, a read-only memory ("ROM"), a random access memory ("RAM"), an electrically erasable programmable read-only memory ("EEPROM"), a flash memory, a hard disk, an SD card, or another suitable magnetic, optical, physical, or electronic memory device. The I/O module <NUM> can include routines for sending information to and receiving information from components or devices external to the controller <NUM> and for transferring information between components within the controller <NUM>. Software included in the implementation of the device <NUM> can be stored in the memory <NUM> of the controller <NUM>. The software includes, for example, firmware applications and other executable instructions for performing the methods described herein. In other embodiments, the controller <NUM> can include additional, fewer, or different components.

The controller <NUM> can be implemented partially or entirely on one or more semiconductor chips (e.g., an application-specific integrated circuit ["ASIC"], a system-on-a-chip ["SOC"], etc.). In some embodiments, one or more field-programmable gate arrays ["FPGA"] semiconductor chips can be used, such as a chip developed through a register transfer level ("RTL") design process. In various embodiments of the invention, the controller <NUM> can be implemented at least partially on, for example, one or more printed circuit boards ("PCBs") within the device <NUM>. For example, the PCB is populated with a plurality of electrical and electronic components which provide operational control and protection to the device <NUM>. The PCB also includes, among other things, a plurality of additional passive and active components such as resistors, capacitors, inductors, integrated circuits, and amplifiers. These components are arranged and connected to provide a plurality of electrical functions to the PCB including, among other things, filtering, signal conditioning, and voltage regulation. For descriptive purposes, the PCB and the electrical components populated on the PCB are collectively referred to as the controller <NUM>. The controller <NUM> receives signals from the radios <NUM> and <NUM> or other components within the device <NUM>, conditions and processes the signals, and transmits processed and conditioned signals to, for example, another component or device within the utility communications network <NUM>, etc..

The power supply module <NUM> includes a power source, such as batteries, a battery pack, a mains power plug, etc. In embodiments of the invention which include batteries, the batteries are alkaline-based or lithium-based batteries and are, for example, disposable or rechargeable AA batteries, AAA batteries, six-volt ("6V") batteries, nine-volt ("9V") batteries, etc..

<FIG> illustrates a multimode receiver <NUM> that includes an intermediate frequency ("IF") filter module <NUM>, an analog-to-digital conversion ("ADC") module <NUM>, a first analysis module <NUM>, a second analysis module <NUM>, a third analysis module <NUM>, and a classification module <NUM>. The receiver <NUM> can, for example, be included in the device <NUM> and be configured to receive a signal from another device within the communications system <NUM>, determine a corresponding communication mode for the received signal, and be configured to receive signals according the determined communications mode. For example, the receiver <NUM> is configured for cost-effective, multimode signal acquisition of signals of a plurality of different communication modes that operate within the same frequency band. Such communication modes include, for example, the FSK, OFDM, and O-QPSK communication modes of the IEEE <NUM>. <NUM> standard, the IEEE <NUM> standard, etc., operating in the <NUM>-<NUM> industrial, scientific, and medical ("ISM") frequency bands.

The IF filter <NUM> is configured to shift the received signal's carrier frequency to an intermediate range of frequencies that is more suitable for processing and analysis. The filtered output of the IF filter <NUM> is provided to the ADC module <NUM> for sampling. The sampled output of the ADC module <NUM> is then provided to the first analysis module <NUM>, the second analysis module <NUM>, and the third analysis module <NUM>. Although three analysis modules are illustrated, the receiver <NUM> can include additional or fewer analysis models, depending on the embodiment of the invention. Each of the illustrated analysis modules <NUM>, <NUM>, and <NUM> is configured to execute one or more frequency analysis processes for determining a characteristic of the received signal (e.g., amplitude, power, PSD, etc.).

In some embodiments, the analysis modules <NUM>, <NUM>, and <NUM> are configured to analyze the preamble or syncword of a received signal to identify its corresponding communication mode. Generally, the preamble is used to identify the start of the data within a bit stream of data. However, depending on the communication mode in which the data was transmitted, the spectral content of the preamble can vary. As a result, by analyzing specific frequencies or ranges of frequencies related to the received preamble, the corresponding communication mode can be identified. As an illustrative example, each of the analysis modules <NUM>, <NUM>, and <NUM> is configured to execute instructions stored in, for example, the memory <NUM> of the controller <NUM> for performing a Goertzel analysis to identifying characteristics of specific frequency components of the received signal or a portion of the received signal (e.g., the preamble of the received signal). The Goertzel analysis includes executing one or more Goertzel algorithms for various communication modes. Depending on the communication mode, the Goertzel algorithm can be tuned to different frequencies of interest.

For example, in a general implementation, an analysis module executes a Goertzel algorithm to compute a sequence, s(n), given an input sequence x(n), as shown below in EQN. <MAT> where s(-<NUM>) = s(-<NUM>) = <NUM> and ω is a frequency of interest. The z-transform of EQN. <NUM> produces EQN. <NUM> below.

Applying an additional finite impulse response ("FIR") transform in the form of EQN. <NUM> below <MAT> produces an overall transform as provided in EQN.

The above transform and the operation of the analysis modules <NUM>, <NUM>, and <NUM> can be expanded to identify characteristics of multiple frequencies of interest within the received baseband signal. For example, the Goertzel technique described above can be applied for the FSK modes of the IEEE <NUM>. <NUM> standard. These FSK modes have a set of candidate frequencies corresponding to baud rates for the received signal (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc.). In some embodiments, a range or window of frequencies around each of the candidate frequencies is used to allow for variance in the received signals without affecting the identification of the communication mode. Candidate frequencies for other communication modes (e.g., OFDM, QPSK, O-QPSK, etc.) can similarly by identified using the analysis modules <NUM>, <NUM>, and <NUM>. In some embodiments, the analysis modules <NUM>, <NUM>, and <NUM> can also be used to identify the baud rate of a received signal.

The outputs of each of the analysis modules <NUM>, <NUM>, and <NUM> are then provided to the classification module <NUM>. The classification module <NUM> determines the communication mode of the received signal by comparing a value for a characteristic (e.g., amplitude, power, PSD, etc.) of the received signal with one or more expected characteristic values at each candidate frequency for the various communication modes.

For example, the receiver <NUM> is able to use relationships between the power associated with the received signal at the candidate frequencies and a plurality of communication modes to identify the communication mode of the received signal. For example, the relationships between a power of a received signal at the candidate frequencies and the expected power at the candidate frequencies for each of the plurality of communication modes are stored in memory (e.g., the memory <NUM>). The relationships can be stored as one or more functions, one or more look up tables ("LUTs"), or as a series of thresholds to which the power for particular frequencies may be compared.

With respect to implementations of the invention in which a LUT is used, values of, for example, amplitude, power, PSD, or another characteristic are stored in memory corresponding to a plurality of frequencies of interest for various communication modes. In some embodiments, <NUM>-bit numbers (i.e., <NUM> values) or <NUM>-bit numbers (i.e., <NUM>,<NUM> values) are used to identify the characteristic value of a received signal at a particular frequency. In some embodiments, the resolution of the characteristic value comparison is based on the resolution of the ADC module <NUM> used for sampling the received signal. The characteristic value is then used as an input value that is compared to the values stored in the LUT for the various communication modes. The LUT entry or entries that correspond to the characteristic value of the received signal is then identified by the classification module <NUM>. Additional comparisons can be made to determine whether the received signal is associated with a known communication mode. If there is a sufficient correlation between the received signal and the expected characteristic values, the classification module <NUM> identifies the communication mode of the received signal. A sufficient correlation may be identified using, for example, a predetermined or calculated percent error value, an error range, etc. Additionally or alternatively, the classification module <NUM> may have to identify a characteristic value at each of the expected frequencies in the received signal before identifying the communication mode. In such embodiments, the identification of the communication mode may not be made if one or more frequencies or frequency components of sufficient amplitude, power, PSD, etc., are not present. With respect to implementations of the invention that use a variety of threshold values, the characteristic value can be compared sequentially to a series of threshold values. The threshold values correspond to values of the characteristic at the specified frequencies that are indicative of a particular communication mode.

If one match to a communication mode is found, then the preamble of a single carrier signal operating at the matching baud rate is likely being received. The device <NUM> can then be automatically reconfigured for full acquisition of signals transmitted using the identified communication mode (e.g., the preamble for the identified communication mode is then assumed to be received). If multiple matches are found, a multi-carrier signal spanning the detected tones is likely being received. The device <NUM> can then be automatically reconfigured accordingly for the full acquisition of such signals.

<FIG> and <FIG> illustrate PSD plots <NUM> and <NUM>, respectively, of two different communication modes. PSD is illustrated in units of power (decibels ["dB"]) per Hertz ("Hz"). In <FIG>, the PSDs <NUM> and <NUM> for a first communication mode and a <NUM> kbps data link with modulation indices, h, of <NUM> and <NUM>, respectively, are shown. In other embodiments, the energy spectral density ("ESD") can be used in place of or in addition to the PSD. As shown in the PSDs <NUM> and <NUM>, the signal preamble for the illustrated communication mode has characteristic frequency peaks that can be used to identify the communication mode of the received signal. For example, executing a Goertzel algorithm as described above with frequencies of interest at <NUM> and one or more other frequencies, and then comparing the outputs of the Goertzel algorithm to predetermined power density levels (e.g., -<NUM> dB/Hz), allows the receiver <NUM> to identify the communication mode. In <FIG>, the PSDs <NUM> and <NUM> for a second communication mode and a <NUM> kbps data link with modulation indices, h, of <NUM> and <NUM>, respectively, are shown. The frequencies of interest for this communication mode may be <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>. In some embodiments, the number of frequencies of interest used to identify a communication mode can be varied based on, for example, a range of possible frequencies associated with a communication mode. If the output of a corresponding analysis module indicates that the preamble of the received signal includes frequency components at the frequencies of interest that are each above a PSD of, for example, -<NUM> dB/Hz, the associated communication mode can be identified.

By performing a frequency analysis (e.g., Goertzel analysis) of the frequencies associated with a portion of a received signal (e.g., the preamble), and comparing a characteristic (e.g., PSD) at those frequencies to expected characteristic values for various communication modes, the communication mode of the received signal can be quickly and efficiently identified. Such a technique also reduces the computational requirements of the multimode receiver <NUM>, as well as the amount of power that is consumed in determining the communication mode. In some embodiments, automatic gain control ("AGC") can also be performed prior to determining the communication mode.

As an illustrative example, a set of incoming signal samples, x, a vector of desired frequencies, F, and a vector of estimated incoming signal powers, P, at the desired frequencies can be used to classify incoming signals. The vector of desired frequencies, F, corresponds to the baud rates of single-carrier modes of interest and/or the tones of multi-carrier modes of interest. The below pseudo-code is exemplary of an embodiment of the invention for classifying the communication mode of an incoming signal using the Goertzel algorithm. The vector of estimated incoming signal powers, P, is populated by calculating a power value for each of the frequencies of interest in the vector of desired frequencies, F, as shown below.

If the power of an incoming signal is greater than a threshold value at exactly one location, j, within the vector of estimated incoming signal powers, P, then a single carrier signal is detected having a corresponding baud rate, F[j]. If the power of an incoming signal is greater than at least one threshold value at multiple locations (e.g., {jl,. , jn}), then a multi-carrier signal is detected that spans the tones {F(jl,. If the power at a midpoint of the locations jl and jn (e.g., between two tones) is less than one or more threshold values, then the detected multi-carrier signal is an OFDM signal. Further processing can also be performed to classify a detected single-carrier signal by analyzing a ratio of the power at a particular frequency (e.g., the frequency at which the signal power is greater than the threshold value) to the power at the frequency corresponding to the carrier signal. Such an analysis can be used to estimate a modulation index of a single-carrier signal modulated using FSK.

A process <NUM> for determining a communication mode of a received signal is shown in <FIG>. The process <NUM> begins with the reception of a signal (step <NUM>). The signal is, for example, an analog signal that has been transmitted according to a particular modulation or transmission technique, such as FSK, PSK, QPSK, O-QPSK, OFDM, etc., as previously indicated. The received analog signal is then filtered (step <NUM>). Filtering the received analog signal can include the use of an IF filter that shifts the frequency of the carrier signal to a lower frequency for processing and analysis. In some embodiments, the IF filter is associated with a tunable local oscillator ("LO").

Following step <NUM>, the filtered output of the IF filter is provided to an analog-to-digital converter ("ADC") (step <NUM>) for conversion to a digital signal (i.e., sampling). The sampled signal is then provided to one or more analysis modules which perform frequency analysis on the digital form of the received signal (step <NUM>). The frequency analysis can be performed in a number of ways. For example, a Goertzel algorithm, a discrete Fourier transform ("DFT"), a fast Fourier transform ("FFT"), a Cooley-Tukey FFT algorithm, etc. In some embodiments, different frequency analysis techniques can be used to identify different communication modes. The selection of a frequency analysis technique may be based on the factors such as computational complexity, available hardware resources, power requirements, etc. In some embodiments, the Goertzel algorithm is used because it can be tuned to specific frequencies and can be implemented using fewer mathematical operations (e.g., additions, subtractions, multiplications, etc.). Additionally or alternatively, another technique designed to identify or analyze specific frequencies or a narrow band of frequencies can be used to identify the characteristics of the preamble a received signal. As a result, the hardware resources required to implement the multimode receiver can be reduced, the power required to perform the frequency analysis can be reduced, and the amount of time required to complete the analysis can be reduced. The number of analysis modules present in the multimode receiver can vary depending upon the number of different communication modes the receiver is configured to identify (e.g., one analysis module for each communication mode). After the frequency content of the signals has been analyzed, the outputs of the analysis modules are provided to a classification module. The classification module compares, for example, a PSD for one or more frequencies of interest specific to the different communication modes to predetermined PSD values at those specific frequencies for each of the communication modes. Based upon the comparisons of the PSD values for the various communication modes, the communication mode may be determined (step <NUM>). Following the determination of the communication mode, the multimode receiver is configured (e.g., automatically configured or reconfigured) for the full acquisition of signals transmitted according to the determined communication mode (step <NUM>).

Claim 1:
A device (<NUM>) configured to process digital signals, the device comprising:
a sampling module (<NUM>) configured to sample a received signal to generate a sampled signal;
one or more analysis modules (<NUM>, <NUM>, <NUM>), a respective analysis module (<NUM>) of the one or more analysis modules configured to analyze a characteristic of the sampled signal associated with a respective plurality of windows of frequencies associated with a respective communication mode of a plurality of communication modes to generate one or more respective values for the characteristic, wherein the characteristic comprises one or more of amplitude, power, or power spectral density; and
a classification module (<NUM>) configured to determine a communication mode of the received signal from the plurality of communication modes based on the one or more respective values.