Communication receiver enhancements using multi-signal capture

A method and apparatus is disclosed to determine communications receiver parameters from multiple channels of a received communications signal and to configure and/or adjust communications receiver parameters to acquire one or more channels from among the multiple channels of the received communications signal. A communications receiver observes a multi-channel communication signal as it passes through a communication channel. The communications receiver determines one or more communications receiver parameters from the multiple channels of the received communications signal. The communications receiver configures and/or adjusts communications receiver parameters to acquire the one or more channels from among the multiple channels of the received communications signal.

BACKGROUND

1. Field of Invention

The present invention relates generally to a communication receiver and specifically to communication receivers using mixed-signals, namely analog and digital, technology.

2. Related Art

Conventional broadband communication systems are increasingly becoming capable of receiving multiple channels simultaneously from among a set of communication channels tor a given communication service or system across the allocated spectrum.

The conventional broadband communication system may include a conventional communications receiver that may be implemented using a single heterodyne or homodyne front end module. These conventional single heterodyne or homodyne front end modules may simultaneously receive multiple channels using a wide intermediate frequency (IF) bandwidth that spans across the multiple channels. The conventional communications receiver may include multiple analog-to-digital converters (ADC) to process the output of the conventional single heterodyne or homodyne front end modules to convert the multiple channels into digital form allowing the multiple channels to be separated and demodulated individually. This approach is further described in U.S. patent application Ser. No. 12/553,687, filed on Sep. 3, 2009, and U.S. patent application Ser. No. 12/553,701, filed on Sep. 3, 2009, each of which is incorporated by reference herein in its entirety.

Alternatively, the conventional communications receiver may be implemented with multiple conventional heterodyne or homodyne front end modules. In this implementation, the conventional communications receiver may include the multiple ADCs to process the output of the multiple conventional heterodyne or homodyne front end modules into digital form to separate and demodulate the multiple channels individually.

In another alternate, the conventional communications receiver may be implemented as a direct sampling receiver. In this implementation, the conventional communications receiver directly samples the multiple channels using an ADC to convert the multiple channels into digital form within the allocated bandwidth. This approach is further described in U.S. patent application Ser. No. 10/952,168, filed on Sep. 29, 2004, now U.S. Pat. No. 7,522,901, which is incorporated by reference herein in its entirety. Also incorporated by reference herein in their entirety, U.S. patent application Ser. No. 10/294,048, filed on Nov. 14, 2002, now U.S. Pat. No. 7,203,227 and U.S. patent application Ser. No. 10/809,893, filed Mar. 26, 2004.

Nevertheless, demodulators which follow these conventional radio frequency (RF) front end modules and ADCs continue to be designed using algorithms developed for single-channel front end modules. Thus, there is a need for an apparatus and/or a method that makes use of the availability of the multiple channels to improve performance of the communications receiver that overcomes the shortcomings described above. Further aspects and advantages of the present invention will become apparent from the detailed description that follows.

The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.

DETAILED DESCRIPTION OF THE INVENTION

The exemplary embodiments described herein are provided for illustrative purposes, and are not limiting. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments within the spirit and scope of the invention. Therefore, the Detailed Description is not meant to limit the invention. Rather, the scope of the invention is defined only in accordance with the following claims and their equivalents.

Exemplary Communications Environment

FIG. 1illustrates a block diagram of communications environment according to an exemplary embodiment of the present invention. The communications environment100includes a communications transmitter102to transmit one or more information signals, denoted as sequences of data150, as received from one or more transmitter user devices to a communications receiver106via a communications channel104. The transmitter user devices may include, but are not limited to, personal computers, data terminal equipment, cable modems (CM), set-top boxes, cable modem termination systems (CMTS), telephony devices including cell phones and base stations, broadband media players, personal digital assistants, software applications, and/or any other device that is capable of transmitting data that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. The communications transmitter102transmits the sequences of data150to the communications receiver106using a transmitted communications signal152. The transmitted communications signal152represents a communications signal that includes multiple transmitted communications channels, commonly referred to as a wideband multi-channel transmitted communications signal. The transmitted communications signal152may allocate one or more of the multiple transmitted communications channels within the transmitted communications signal152to the one or more transmitter user devices.

The transmitted communications signal152passes through the communications channel104to provide a received communications signal154. The communications channel104may include, but is not limited to, a microwave radio link, a satellite channel, a fiber optic cable, a hybrid fiber optic coaxial cable system, or a copper cable to provide some examples.

The communications receiver106observes the received communications signal154as it passes through the communications channel104. The received communications signal154represents a wideband multi-channel received communications signal having multiple received communications channels. However, the communications channel104, as well as elsewhere in the communications environment100, may embed interference within and/or impress distortion onto the multiple received communications channels causing them to differ from the multiple transmitted communications channels. For example, this interference and/or distortion may cause the multiple received communications channels to differ in frequency, phase, and/or amplitude from the transmitted multiple communications channels. The communications receiver106compensates for the interference embedded within and/or the distortion impressed onto the received communications signal154. The communications receiver106then attempts to determine an estimate of the transmitted sequence150, often with the goal of generating the most-likely transmitted sequence based upon the received signal154, for each of the multiple transmitted communications channels, or combinations of the multiple transmitted communications channels, of the transmitted communications signal152from the received communications signal154to provide one or more recovered information signals, denoted as recovered sequences of data156, for one or more receiver user devices. The receiver user devices include, but are not limited to, personal computers, data terminal equipment, cable modems (CM), set-top boxes, cable modem termination systems (CMTS), telephony devices including cell phones and base stations, broadband media players, personal digital assistants, software applications, and/or any other device that is capable of receiving data that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

Communications Receiver Implemented as Part of the Communications Environment

FIG. 2further illustrates a block diagram of a communications receiver implemented as part of the communications environment according to an exemplary embodiment of the present invention. A communications receiver200observes the received communication signal154as it passes through the communications channel104. The communications receiver200attempts to determine an estimate of the transmitted sequence for one or more of the multiple transmitted communications channels, or combinations of the multiple transmitted communications channels, of the transmitted communications signal152from the received communications signal154to provide the recovered sequences of data156. The communication receiver200may represent an exemplary embodiment of the communications receiver106.

The communications receiver200includes a front end module202, a demodulator module204, and a decoder module206. The front end module202provides a digital sequence of data250or multiple digital sequences of data250.1through250.nbased upon the received communications signal154. The front end module202may amplify the received communications signal154, filter the received communications signal154to remove unwanted noise and/or interference, convert the received communications signal154from an analog representation to a digital representation, frequency translate the received communications signal154to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention, and/or any combination thereof. The front end module202may include one or more carrier frequency loops to compensate for unknown frequency offsets between the communications transmitter102and the communications receiver200and/or one or more timing loops to compensate for unknown timing offsets between the communications transmitter102and the communications receiver200.

The demodulator module204demodulates the digital sequence of data250using any suitable analog or digital demodulation technique for any suitable modulation technique such as amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), phase shift keying (PSK), frequency shift keying (FSK), amplitude shift keying (ASK), quadrature amplitude modulation (QAM) and/or any other suitable demodulation technique that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to provide a demodulated sequence of data252. The demodulator module204may include one or more adaptive equalizers to compensate for unwanted distortion impressed upon the digital sequence of data250by the communications channel104. The one or more adaptive equalizers may adapt their impulse responses by updating one or more equalization coefficients through a least-squares algorithm, such as the widely known Least Mean Squared (LMS), Recursive Least Squares (RLS), Minimum Mean Squared Error (MMSE) algorithms or any suitable equivalent algorithm that yields an optimized result that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. Additionally, the demodulator module204may decode the digital sequence of data250according to a multiple access transmission scheme such as code division multiple access (CDMA), synchronous CDMA (S-CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), discrete multi-tone (DMT) modulation, orthogonal frequency division multiple access (OFDMA) and/or any other suitable multiple access scheme that will be apparent by those skilled in the relevant art(s).

The decoder module206performs error correction decoding upon the recovered sequence of data252using any suitable decoding scheme that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to provide the one or more recovered information signals156. The decoding scheme may include a block decoding scheme, such as Reed-Solomon decoding, a convolutional decoding scheme, such as the Viterbi algorithm, a concatenated decoding scheme involving inner and outer codes, decoding schemes using iterative decoding, partial decoding, iterative decoding involving iterations between channel estimation and partial decoding and full decoding with impulse or burst noise and/or noise unequally distributed among the signaling dimensions such as colored noise, and/or any other suitable decoding scheme that will be apparent to those skilled in the art(s).

First Conventional Front End Module that is Implemented as Part of the Communication Receiver

FIG. 3Aillustrates a block diagram of a conventional front end module that is implemented as part of the communications receiver. A conventional front end module300converts the multiple received communications channels of the received communications signal154from an analog representation into a digital representation to provide the digital sequence of data250. The conventional front end module300includes a heterodyne/homodyne receiver302and an analog-to-digital converter (ADC)304. The conventional front end module300may represent an exemplary embodiment of the front end module202.

The heterodyne/homodyne receiver302downconverts the multiple received communications channels of the received communications signal154to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to provide a downconverted communications signal350. The downconverted communications signal350includes each of the multiple received communications channels that have been downconverted to approximately baseband or the suitable IF.

The ADC304converts the downconverted communications signal350from the analog representation into the digital representation to provide the digital sequence of data250. The ADC304converts the multiple received communications channels that have been downconverted to approximately baseband or the suitable IF into the digital representation.

The conventional front end module300is further described in U.S. patent application Ser. No. 12/553,687, filed on Sep. 3, 2009, and U.S. patent application Ser. No. 12/553,701, filed on Sep. 3, 2009, each of which is incorporated by reference herein in its entirety.

Second Conventional Front End Module that is Implemented as Part of the Communication Receiver

FIG. 3Billustrates a block diagram of a second conventional front end module that is implemented as part of the communications receiver. A conventional front end module306converts a complex representation of the multiple received communications channels of the received communications signal154from an analog representation into a digital representation to provide an in-phase digital sequence of data250.1and a quadrature phase digital sequence of data250.2. The conventional front end module306includes a heterodyne/homodyne receiver308and analog-to-digital converters (ADCs)310.1and310.2. The conventional front end module306may represent an exemplary embodiment of the front end module202.

The multiple received communications channels of the received communications signal154may be represented as a complex communication signal having an in-phase component and a quadrature phase component.

The heterodyne/homodyne receiver308downconverts the in-phase component and the quadrature phase component of the multiple received communications channels of the received communications signal154to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to provide an in-phase downconverted communications signal352.1and a quadrature phase downconverted communications signal352.2, respectively. The downconverted communications signals352.1and352.2include each of the multiple received communications channels that have been downconverted to approximately baseband or the suitable IF.

The ADC310.1and the ADC310.2converts the in-phase downconverted communications signal352.1and the quadrature phase downconverted communications signal352.2, respectively, from the analog representation into the digital representation to provide the in-phase digital sequence of data250.1and the quadrature phase digital sequence of data250.2, respectively. The ADC310.1and the ADC310.2converts the multiple received communications channels that have been downconverted to approximately baseband or the suitable IF into the digital representation.

Third Conventional Front End Module that is Implemented as Part of the Communication Receiver

FIG. 4illustrates a block diagram of a third conventional front end module that is implemented as part of the communications receiver. A conventional front end module400converts the multiple received communications channels of the received communications signal154from an analog representation into a digital representation to provide the digital sequences of data250.1through250.n. The conventional front end module400includes heterodyne/homodyne receivers402.1through402.nand analog-to-digital converters (ADC)404.1through404.n. The conventional front end module400may represent an exemplary embodiment of the front end module202.

The heterodyne/homodyne receivers402.1through402.ndownconvert the multiple received communications channels of the received communications signal154to approximately baseband or a suitable IF that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to provide downconverted communications signals450.1through450.n. Each of the downconverted communications signals450.1through450.nincludes one or more of the multiple received communications channels that have been downconverted to approximately baseband or the suitable IF.

The ADCs404.1through404.nconvert the downconverted communications signals450.1through450.nfrom the analog representation into the digital representation to provide the digital sequences of data250.1through250.n. The ADCs404.1through404.nconvert the multiple received communications channels from their corresponding downconverted communications signal450.1through450.nthat have been downconverted to approximately baseband or the suitable IF into the digital representation.

Fourth Conventional Front End Module that is Implemented as Part of the Communication Receiver

FIG. 5illustrates a block diagram of a fourth conventional front end module that is implemented as part of the communications receiver. A conventional front end module500converts the multiple received communications channels of the received communications signal154from an analog representation into a digital representation to provide the digital sequence of data250. The conventional front end module500includes an analog-to-digital converter (ADC)502. The conventional front end module500may represent an exemplary embodiment of the front end module202.

The ADC502converts the received communications signal154from the analog representation into the digital representation to provide the digital sequence of data250. The ADC502converts the multiple received communications channels of the received communications signal154into the digital representation250.

The conventional front end module500is further described in U.S. patent application Ser. No. 10/952,168, filed on Sep. 29, 2004, now U.S. Pat. No. 7,522,901, which is incorporated by reference herein in its entirety.

Exemplary Embodiment of a First Front End Module that is Implemented as Part of the Communications Receiver

FIG. 6illustrates a block diagram of a first front end module that is implemented as part of the communications receiver according to an exemplary embodiment of the present invention. A front end module600includes an optional amplifier module602, an auxiliary front end module604, a main front end module606, and a parameter estimation module608. The front end module600may represent an exemplary embodiment of the front end module202. The front end module600may be optionally coupled to a demodulator module610.

The optional amplifier module602may amplify the received communications signal154according to an amplifier gain g to provide an amplified communications signal650.

The auxiliary front end module604and the main front end module606may process the received communications signal154, or optionally, the amplified communications signal650, to provide the digital sequence of data250and an auxiliary digital sequence of data652. For example, the auxiliary front end module604and/or the main front end module606may filter the amplified communications signal650, remove unwanted noise and/or interference from the amplified communications signal650, convert the amplified communications signal650from an analog representation to a digital representation, frequency translate the amplified communications signal650to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention, and/or any combination thereof. In this example, the auxiliary front end module604and/or the main front end module606may communicate information resulting from their respective processes to the parameter estimation module608as a main module information658and/or an auxiliary module information660, respectively.

Generally, the auxiliary front end module604and/or the main front end module606may be a direct sampling front end module or a conversion based front end module. For example, the auxiliary front end module604and/or the main front end module606may be implemented using the conventional front end module300, the conventional front end module306, the conventional front end module400, the conventional front end module500, any other suitable front end module that is capable of processing the amplified communications signal650from the analog representation to the digital representation that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention, or portions and/or combinations thereof.

The auxiliary front end module604and the main front end module606provide an auxiliary digital sequence of data652and the digital sequence of data250, respectively, based upon the amplified communications signal650. Typically, the auxiliary digital sequence of data652may be characterized as including a greater number of received communications channels when compared to the digital sequence of data250. For example, the digital sequence of data250may represent a narrow band communications signal having a smaller number of received communications channels and the auxiliary digital sequence of data652may represent a wideband communications signal having a larger number of received communications channels. In an exemplary embodiment, the auxiliary front end module604is characterized as having a lesser dynamic range than the main front end module606.

The parameter estimation module608estimates one or more communications receiver parameters654based upon the digital sequence of data250, the auxiliary digital sequence of data652, demodulator information656, main module information658and/or auxiliary module information660. The demodulator information656, the main module information658and the auxiliary module information660may represent information that is communicated from the auxiliary front end module604, the main front end module606, and the demodulator module610, respectively.

In an exemplary embodiment, the parameter estimation module608may estimate the one or more communications receiver parameters654based upon the auxiliary digital sequence of data652. Typically, in this example, the one or more communications receiver parameters654may include automatic gain control (AGC) parameters, adaptive filter coefficients, sampling clock characteristics, local oscillator characteristics, carrier tracking loop parameters, timing loop parameters, adaptive equalization coefficients, frequency compensation parameters, phase compensation parameters, offset compensation parameters, and/or any other suitable parameter that may be used by the communications receiver200, the front end module600, and/or the main front end module606that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. In this exemplary embodiment, the parameter estimation module608estimates the one or more communications receiver parameters654for a greater number of received communications signals and/or channels which is then applied to process a lesser number of received communications signals and/or channels. For example, the parameter estimation module608may estimate AGC parameters for m communications signals and/or channels and use these AGC parameters as a basis for determining AGC parameters for n communications signals and/or channels, where m is greater than or equal n. As another example, the parameter estimation module608may estimate carrier tracking loop parameters for the m communications signals and/or channels and use these carrier tracking loop parameters as a basis for determining timing loop parameters for the n communications signals and/or channels. As a further example, the parameter estimation module608may estimate timing loop parameters for the m communications signals and/or channels and use these timing loop parameters as a basis for determining timing loop parameters for the n communications signals and/or channels.

In another exemplary embodiment, the parameter estimation module608may estimate the one or more communications receiver parameters654based upon a relationship between the digital sequence of data250and the auxiliary digital sequence of data652. Typically, in this embodiment, the one or more communications receiver parameters654may include a phase offset between the auxiliary digital sequence of data652and the digital sequence of data250, a frequency offset between the auxiliary digital sequence of data652and the digital sequence of data250, a timing offset between the auxiliary digital sequence of data652and the digital sequence of data250and/or any other suitable parameter that may be used by the communications receiver200, the front end module600, and/or the main front end module606that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

In a further exemplary embodiment, the parameter estimation module608may estimate the one or more communications receiver parameters654based upon the main module information658and/or the auxiliary module information660. For example, the auxiliary front end module604and/or the main front end module606may include one or more carrier frequency loops to compensate for unknown frequency offsets between the communications transmitter102and the communications receiver200and/or one or more timing loops to compensate for unknown timing offsets between the communications transmitter102and the communications receiver200. The auxiliary front end module604and/or the main front end module606may communicate the unknown frequency offsets and/or the unknown timing offsets to the parameter estimation module608as the main module information658and the auxiliary module information660, respectively. In this exemplary embodiment, the parameter estimation module608may use the main module information658and the auxiliary module information660to estimate the unknown frequency offsets and/or the unknown timing offsets for the m communications signals and/or channels and use these unknown frequency offsets and/or the unknown timing offsets as a basis for determining the unknown frequency offsets and/or the unknown timing offsets for the n communications signals and/or channels n.

In a yet further embodiment, the parameter estimation module608may estimate the one or more communications receiver parameters654based upon the demodulator information656. For example, the demodulator module610may include one or more adaptive equalizers to compensate for unwanted distortion impressed upon the digital sequence of data250by the communications channel104. The one or more adaptive equalizers may adapt their impulse responses by updating one or more equalization coefficients through a least-squares algorithm, such as the widely known Least Mean Squared (LMS), Recursive Least Squares (RLS), Minimum Mean Squared Error (MMSE) algorithms or any suitable equivalent algorithm that yields an optimized result that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. The demodulator module610may communicate the one or more equalization coefficients to the parameter estimation module608as the demodulator information656. In this exemplary embodiment, the parameter estimation module608may use the demodulator information656to estimate the one or more equalization coefficients for the m communications signals and/or channels and use these one or more equalization coefficients as a basis for determining the one or more equalization coefficients for the n communications signals and/or channels.

However, these exemplary embodiments are not limiting, those skilled in the relevant art(s) will recognize that the parameter estimation module608may estimate any other suitable communications parameter for the m communications signals and/or channels and use this other suitable communications parameter as a basis for determining another suitable communications parameter for the n communications signals and/or channels using any combination of the digital sequence of data250, the auxiliary digital sequence of data652, the demodulator information656, the main module information658and/or the auxiliary module information660without departing from the spirit and scope of the present invention.

The demodulator610demodulates and/or decodes the digital sequence of data250in accordance with the one or more communications receiver parameters654to provide the demodulated sequence of data252. The demodulator610may represent an exemplary embodiment of the demodulator204.

FIG. 6Bis a flowchart of exemplary operational steps of the parameter estimation module that is implemented as part of the front end module receiver according to an exemplary embodiment of the present invention. The invention is not limited to this operational description. Rather, it will be apparent to persons skilled in the relevant art(s) that other operational control flows are within the scope and spirit of the present invention. The following discussion describes the steps inFIG. 6B.

At step690, the operational control flow estimates one or more signal metrics of the multiple received communications channels embedded within a recovered digital communications signal, such as the auxiliary digital sequence of data652to provide an example. The operational control flow may use a Fast Fourier Transform (FFT) or any other suitable digital signal processing algorithm that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to determine the one or more signal metrics.

At step692, the operational control flow compares the one or more signal metrics from step690to determine a statistical relationship between the one or more signal metrics.

At step694, the operational control flow determines one or more communications receiver parameters, such as the one or more communications receiver parameters654to provide an example, using the statistical relationship from step692.

FIG. 7Agraphically illustrates a first operation of a parameter estimation module that is implemented as part of the front end module according to an exemplary embodiment of the present invention. Specifically,FIG. 7Agraphically illustrates a frequency domain representation of the received communications signal154, the digital sequence of data250, and the auxiliary digital sequence of data652. The received communications signal154may be characterized as including received communications channels CH1through CH5. The auxiliary front end module604provides the auxiliary digital sequence of data652that may be characterized as including received communications channels CH1through CH5. The main front end module606provides the digital sequence of data250that may be characterized as including received communications channel CH2. However, these characterizations of the received communications signal154, the digital sequence of data250, and the auxiliary digital sequence of data652are for illustrative purposes only, those skilled in the relevant art(s) will recognize that the received communications signal154, the digital sequence of data250, and/or the auxiliary digital sequence of data652may include more or less received communications channels and/or different received communications channels than illustrated without departing from the spirit and scope of the present invention.

The parameter estimation module608estimates one or more signal metrics of the received communications channels CH1through CH5embedded within the auxiliary digital sequence of data652without departing from the spirit and scope of the present invention. The one or more signal metrics may include a mean, a total energy, an average power, a mean square, an instantaneous power, a root mean square, a variance, a norm, a voltage level, a phase offset between the auxiliary digital sequence of data652and the digital sequence of data250, a frequency offset between the auxiliary digital sequence of data652and the digital sequence of data250, a timing offset between the auxiliary digital sequence of data652and the digital sequence of data250, synchronization epoch information such as puncture alignment of a decoder and/or facilitating upstream synchronization, and/or deinterleaver timing, and/or frame synchronization timing, or any other suitable signal metric of the received communications channels CH1through CH5which will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention, and/or any combination thereof. For example, the parameter estimation module608may determine a corresponding instantaneous power P1through Psfor the received communications channels CH1through CH5. However, this example is not limiting, those skilled in the relevant art(s) will recognize that the parameter estimation module608may determine other AGC parameters, carrier tracking loop parameters, timing loop parameters, adaptive equalization coefficients, and/or any other suitable communications receiver parameter that may be used by the communications receiver200and/or the front end module600that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. The parameter estimation module608may use a Fast Fourier Transform (FFT) or any other suitable digital signal processing algorithm that will be apparent to those skilled in the relevant art(s) to determine the one or more signal metrics.

The parameter estimation module608compares the one or more signal metrics to determine a statistical relationship between the one or more signal metrics. The statistical relationship may include a mean, medium, maximum, minimum, correlation, auto-correlation, or any other suitable statistical measurement that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. From the example above, the parameter estimation module608may compare the instantaneous powers P1through P5to determine a maximum instantaneous power from among instantaneous powers P1through P5.

The parameter estimation module608determines the one or more communications receiver parameters654based upon the statistical relationship between the one or more signal metrics. In this example, the parameter estimation module608determines, as the one or more communications receiver parameters654, a corresponding AGC parameter to be used by the front end module600based upon the instantaneous power P3.

Referring again toFIG. 6A, the front end module600may use the one or more communications receiver parameters654to configure and/or adjust operational settings such as AGC settings, carrier tracking loop settings, timing loop settings, adaptive equalization coefficients, and/or any other suitable communications receiver setting that may be used by the communications receiver200and/or the front end module600to recover the recovered sequences of data156from the received communications signal154that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

As an example, the optional amplifier module602may use the one or more communications receiver parameters654to configure and/or adjust use the amplifier gain g that is used to amplify the multiple received communications channels of the received communications signal154.

As another example, the main front end module606may use the one or more communications receiver parameters654to configure and/or adjust its operational settings. For example, the main front end module606may configure and/or adjust operational settings used to filter the amplified communications signal650to remove unwanted noise and/or interference to convert the amplified communications signal650from the analog representation to the digital representation, to frequency translate the amplified communications signal650to approximately baseband or the suitable intermediate frequency (IF), and/or any combination thereof.

As a further example, the main front end module606may configure and/or adjust operational settings for one or more carrier frequency loops to compensate for unknown frequency offsets between the communications transmitter102and the communications receiver200and/or one or more timing loops to compensate for unknown timing offsets between the communications transmitter102and the communications receiver200.

FIG. 7Bgraphically illustrates a second operation of the parameter estimation module. Specifically,FIG. 7Bgraphically illustrates a frequency domain representation of the received communications signal154, the digital sequence of data250, and the auxiliary digital sequence of data652. The received communications signal154may be characterized as including received communications channels CH1through CH5. The auxiliary front end module604provides the auxiliary digital sequence of data652that may be characterized as including received communications channels CH1through CH5. The main front end module606provides the digital sequence of data250that may be characterized as including received communications channels CH3and CH4. However, these characterizations of the received communications signal154, the digital sequence of data250, and the auxiliary digital sequence of data652are for illustrative purposes only, those skilled in the relevant art(s) will recognize that the received communications signal154, the digital sequence of data250, and/or the auxiliary digital sequence of data652may include more or less received communications channels and/or different received communications channels than illustrated without departing from the spirit and scope of the present invention.

As shown inFIG. 7B, an expected frequency fE1through fE5for each of the received communications channels CH1through CH5is offset from an actual frequency fA1through fA5by a corresponding frequency offset fO1through fO5. The actual frequencies fA1through fA5represent one or more frequencies within the auxiliary digital sequence of data652as received by the front end module600. However, the actual frequencies fA1through fA5are offset from their corresponding expected frequencies fE1through fE5by their corresponding frequency offsets fO1through fO5.

The parameter estimation module608estimates the frequency offsets fO1through fO5within the auxiliary digital sequence of data652to provide a carrier offset discriminate function corresponding to the received communications channels CH1through CH5. For example, as shown inFIG. 7B, the frequency offsets fO1through fO5are largely proportional to their corresponding actual frequencies fA1through fA5. In this example, the parameter optimization module608may determine a carrier offset discriminate function, usually in terms of part per million, that characterizes the frequency offsets fO1through fO5for the received communications channels CH1through CH5. As another example, the frequency offsets fO1through fO5are substantially similar to each other. In this example, the parameter optimization module608may determine a carrier offset discriminate function that characterizes the frequency offsets fO1through fO5for the received communications channels CH1through CH5. As a further example, the frequency offsets fO1through fO5may be any combination of this substantially similar offset and the largely proportional offset as described above. As a yet further example, the parameter optimization module608may be provided information relating to the frequency offsets fO1through fO5or knows this information from previous and current acquisition and tracking. In this example, the parameter estimation module608may determine a carrier offset discriminate function that characterizes the frequency offsets fO1through fO5for the received communications channels CH1through CH5using this information.

The parameter estimation module608determines the one or more communications receiver parameters654that may be used to compensate for the frequency offsets fO3and fO4within the received communications channels CH3and CH4based upon the carrier offset discriminate function that has been determined based upon the received communications channels CH1through CH5.

Alternatively, the one or more communications receiver parameters654may represent initial operational settings for acquisition of the multiple received communications channels of the received communications signal154. The auxiliary front end module604and the parameter estimation module608determine the one or more communications receiver parameters654using the multiple received communications channels, as described above, before acquisition of the multiple received communications channels by the main front end module606. The main front end module606may use these near correct initial operational settings established from the multiple received communications channels to substantially lessen acquisition time of the multiple received communications channels. Alternatively, the main front end module606may use these near correct initial operational settings established from the multiple received communications channels to substantially lessen acquisition time when switching from among the multiple received communications channels.

FIG. 7Cgraphically illustrates a third operation of the parameter estimation module according to an exemplary embodiment of the present invention. Specifically,FIG. 7Cgraphically illustrates a time domain representation of the received communications signal154, the digital sequence of data250, and the auxiliary digital sequence of data652. The received communications signal154may be characterized as including received communications channels CH1through CH3. The auxiliary front end module604provides the auxiliary digital sequence of data652that may be characterized as including received communications channels CH1through CH3. The main front end module606provides the digital sequence of data250that may be characterized as including received communications channels CH3. However, these characterizations of the received communications signal154, the digital sequence of data250, and the auxiliary digital sequence of data652are for illustrative purposes only, those skilled in the relevant art(s) will recognize that the received communications signal154, the digital sequence of data250, and/or the auxiliary digital sequence of data652may include more or less received communications channels and/or different received communications channels than illustrated without departing from the spirit and scope of the present invention.

Shown inFIG. 7Care eye-diagrams for symbols S1through SKfor the received communications channels CH1through CH3. Each of the symbols S1through SKfor each of the received communications channels CH1through CH3is expected to be sampled at its eye-diagram's respective maximum value. For example, the symbol S1of CH1is expected to be sampled at tE1.1, the symbol S1of CH2is expected to be sampled at tE1.2, and the S1of CH3is expected to be sampled at tE1.3. As another example, the symbol S2of CH1is expected to be sampled at tE1.2, the symbol S2of CH2is expected to be sampled at tE2.2, and the S2of CH3is expected to be sampled at tE2.3. As a further example, the symbol Skof CH1is expected to be sampled at tEk.1, the symbol Skof CH2is expected to be sampled at tEk.2, and the Skof CH3is expected to be sampled at tEk.3.

However, each of the symbols S1through SKfor each of the received communications channels CH1through CH3is actually sampled at values that differ from their expected values. For example, the symbol S1of CH1is actually sampled at tA1.1, the symbol S1of CH2is actually sampled at tA1.2, and the S1of CH3is actually sampled at tA1.3. As another example, the symbol S2of CH1is actually sampled at tA1.2, the symbol S2of CH2is actually sampled at tA2.2, and the S2of CH3is actually sampled at tA2.3. As a farther example, the symbol Skof CH1is actually sampled at tAk.1, the symbol Skof CH2is actually sampled at tAk.2, and the Skof CH3is actually sampled at tAk.3.

The parameter estimation module608estimates the difference between the expected sampling time and the actual sampling time for the symbols S1through SKwithin the auxiliary digital sequence of data652to provide a corresponding timing error descriminate TC1through TCKfor the symbols S1through SK. The timing error discriminates TC1through TCKmay be the same for each symbol or differ between symbols. The timing error discriminates TC1through TCKrepresent a general timing error discriminate that is determined from the received communications channel CH1through CH3. For example, the difference between the expected sampling time and the actual sampling time for the symbols S1through SKare substantially similar for the received communications channel CH1through CH3. Therefore, the general timing error discriminate reduces acquisition of symbol timing for each of the received communications channel CH1through CH3. In another example, the difference between the expected sampling time and the actual sampling time for the symbols S1through SKdiffers between the received communications channel CH1through CH3, but in a manner known or communicated to the parameter estimation module608, thus enabling beneficial use of joint symbol timing across the received communications channel CH1through CH3even with dissimilar timing in each of the received communications channel CH1through CH3.

The parameter estimation module608determines the one or more communications receiver parameters654based upon the timing error discriminates TC1through TCK. The main front end module606may use the one or more communications receiver parameters654as an initial condition to substantially lessen acquisition time of the received communications channel CH3.

FIG. 8graphically illustrates a settling of an AGC loop that is implemented as part of the front end module according to an exemplary embodiment of the present invention. As shown inFIG. 8, a conventional AGC loop requires a first finite amount of time Toto settle to a final value GFduring acquisition of the multiple received communications channels. The initial operating parameters of the conventional AGC loop are unknown during acquisition of the multiple received communications channels causing the conventional AGC loop to adjust its gain from approximately zero gain G0until reaching the final value GF.

However, this example is not limiting, those skilled in the relevant art(s) will recognize that the present invention may be used to determine other communications receiver settings, such as carrier tracking loop settings, timing loop settings, adaptive equalization coefficients to provide some examples, jointly on an ensemble of channels rather than operating on each channel independently without departing from the spirit and scope of the present invention.

FIG. 9further illustrates the block diagram of the first front end module that is implemented as part of the communications receiver according to an exemplary embodiment of the present invention. This exemplary embodiment is not limiting, those skilled in the relevant art(s) will recognize that other embodiments of the front end module are possible without departing from the spirit and scope of the present invention. A front end module900includes the optional amplifier module602, the parameter estimation module608, an auxiliary front end module902, and a main front end module904. The front end module900may represent an exemplary embodiment of the front end module600.

The optional amplifier module602may amplify the received communications signal154to provide the amplified communications signal650.

The auxiliary front end module902provides the auxiliary digital sequence of data652based upon the amplified communications signal650. The auxiliary front end module902may represent an exemplary embodiment of the auxiliary front end module604. The auxiliary front end module902includes an analog to digital converter (ADC)906. The ADC906converts the amplified communications signal650from the analog representation into the digital representation to provide the auxiliary digital sequence of data652. The ADC906converts each of the multiple received communications channels of the amplified communications signal650into the digital representation.

The parameter estimation module608estimates the one or more communications receiver parameters654based upon the digital sequence of data250and/or the auxiliary digital sequence of data652as described above.

The main front end module904provides the digital sequence of data250based upon the amplified communications signal650. The main front end module904includes a channel selection filtering module908, a mixer module910, a local oscillator generator module912, a low pass filtering module914, and an ADC916. The main front end module904may represent an exemplary embodiment of the main front end module606.

The channel selection filtering module908is configured to remove one or more unwanted channels from among the multiple received communications channels embedded within the amplified communications signal650to provide a desired communications channel950, the desired communications channel950including one or more desired channels from among the multiple received communications channels. The channel selection filtering module908may adjust its respective frequency response in response to the one or more communications receiver parameters654. For example, the channel selection filtering module908may adjust its respective filtering bandwidth, center frequency, and/or frequency roll off in response to the one or more communications receiver parameters654.

The mixer module910frequency translates the desired communications channel950using a local oscillator signal952to provide a translated communications channel954. The mixer module910may frequency translate the desired communications channel950to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

The low pass filtering module914removes unwanted noise and/or interference from the translated communications channel954to provide a filtered communications channel956. The low pass filtering module914may adjust its respective frequency response in response to the one or more communications receiver parameters654. For example, the low pass filtering module914may adjust its respective filtering bandwidth, center frequency, and/or frequency roll off in response to the one or more communications receiver parameters654.

The ADC916converts the filtered communications channel956from the analog representation into the digital representation to provide the digital sequence of data250. The ADC916may adjust its sampling clock used to convert the filtered communications channel956from the analog representation into the digital representation response to the one or more communications receiver parameters654. For example, the ADC916may adjust a frequency and/or a phase of its sampling clock in response to the one or more communications receiver parameters654.

Exemplary Embodiment of a Second Front End Module that is Implemented as Part of the Communications Receiver

FIG. 10illustrates a block diagram of a second front end module that is implemented as part of the communications receiver according to an exemplary embodiment of the present invention. A front end module1000includes the optional amplifier module602, the parameter estimation module608, and a main front end module1002. The front end module1000may represent an exemplary embodiment of the front end module202.

The optional amplifier module602may amplify the received communications signal154to provide the amplified communications signal650.

The parameter estimation module608estimates the one or more communications receiver parameters654based upon any combination of the digital sequence of data250, the auxiliary digital sequence of data652, the demodulator information656, and/or the main module information658without departing from the spirit and scope of the present invention as described above.

The main front end module1002may filter the amplified communications signal650, remove unwanted noise and/or interference, convert the amplified communications signal650from an analog representation to a digital representation, frequency translate the amplified communications signal650to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention, and/or any combination thereof. The main front end module1002may include one or more carrier frequency loops to compensate for unknown frequency offsets between the communications transmitter102and the communications receiver200and/or one or more timing loops to compensate for unknown timing offsets between the communications transmitter102and the communications receiver200.

Generally, the main front end module1002may be a direct sampling or a conversion based front end module. For example, the main front end module1002may be implemented using the conventional front end module300, the conventional front end module306, the conventional front end module400, the conventional front end module500, and/or any other suitable front end module that is capable of converting the amplified communications signal650from the analog representation to the digital representation to the digital representation that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

The main front end module1002provides the digital sequence of data250and the auxiliary digital sequence of data652based upon the amplified communications signal650.

The main front end module1002may use the one or more communications receiver parameters654to configure and/or adjust its operational settings. For example, the main front end module1002may configure and/or adjust operational settings used to filter the amplified communications signal650, to remove unwanted noise and/or interference from the amplified communications signal650, to convert the amplified communications signal650from the analog representation to the digital representation, to frequency translate the amplified communications signal650to approximately baseband or the suitable intermediate frequency (IF), and/or any combination thereof. As another example, the main front end module1002may configure and/or adjust operational settings of the one or more carrier frequency loops to compensate for unknown frequency offsets between the communications transmitter102and the communications receiver200and/or the one or more timing loops to compensate for unknown timing offsets between the communications transmitter102and the communications receiver200.

FIG. 11further illustrates the block diagram of the second front end module that is implemented as part of the communications receiver according to an exemplary embodiment of the present invention. This exemplary embodiment is not limiting, those skilled in the relevant art(s) will recognize that other embodiments of the front end module are possible without departing from the spirit and scope of the present invention. A front end module1100includes the optional amplifier module602, the parameter estimation module608, and a main front end module1102. The front end module1100may represent an exemplary embodiment of the front end module1000.

The optional amplifier module602may amplify the received communications signal154to provide the amplified communications signal650.

The parameter estimation module608estimates one or more communications receiver parameters654based upon the digital sequence of data250and/or the auxiliary digital sequence of data652as described above.

The main front end module1104provides the digital sequence of data250and the auxiliary digital sequence of data652based upon the amplified communications signal650. The main front end module1104includes an ADC1104, a multiplication module1106, a local oscillator generator module1108, and a low pass filtering module1110. The main front end module1102may represent an exemplary embodiment of the main front end module1002.

The ADC1104converts the amplified communications signal650from the analog representation into the digital representation to provide the auxiliary digital sequence of data652. The ADC1104may adjust its sampling clock used to convert the amplified communications signal650in response to the one or more communications receiver parameters654. For example, the ADC1104may adjust a frequency and/or a phase of its sampling clock in response to the one or more communications receiver parameters654. The ADC1104converts each of the multiple received communications channels of the amplified communications signal650into the digital representation.

The multiplication module1106frequency translates the auxiliary digital sequence of data652using a local oscillator signal1152to provide a translated sequence of data1154. The multiplication module1106may frequency translate the auxiliary digital sequence of data652to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

The low pass filtering module1110removes unwanted noise and/or interference from the translated sequence of data1154to provide the digital sequence of data250. The low pass filtering module1110may adjust its respective frequency response in response to the one or more communications receiver parameters654. For example, the low pass filtering module1110may adjusts its respective filtering bandwidth, center frequency, and/or frequency roll off in response to the one or more communications receiver parameters654.

Exemplary Embodiment of a Third Front End Module and a Demodulator Module that is Implemented as Part of the Communications Receiver

Referring again toFIG. 6andFIG. 10, the parameter estimation module608may provide the one or more communications receiver parameters654to the front end module600and/or the front end module1000as well as to other modules within the communications receiver200such as the demodulator module204and/or the decoder module206to provide some examples. For example, the demodulator module204may include one or more adaptive equalizers that compensate for unwanted distortion impressed upon the digital sequence of data250by the communications channel104. The one or more adaptive equalizers may adapt their impulse responses by updating one or more equalization coefficients through a least-squares algorithm, such as the widely known Least Mean Squared (LMS), Recursive Least Squares (RLS), Minimum Mean Squared Error (MMSE) algorithms or any suitable equivalent algorithm that yields an optimized result that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention. The demodulator module204may use the one or more communications receiver parameters654to configure and/or adjust the one or more equalization coefficients.

FIG. 12illustrates a block diagram of a third front end module and a demodulator module that is implemented as part of the communications receiver according to an exemplary embodiment of the present invention. A front end module1200includes a mixer module1204, a local oscillator generator1206, and a front end1208. The mixer module1204frequency translates the received communications signal154using a local oscillator signal1252to provide a translated communications signal1250. The mixer module1204may frequency translate the received communications signal154to approximately baseband or a suitable intermediate frequency (IF) that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention.

The local oscillator generator module1206provides the local oscillator signal1252. The local oscillator signal1252may be characterized as having phase noise. This phase noise is common between the multiple channels of the translated communications signal1250.

The front end module1208provides the digital sequences of data250.1through250.nbased upon the translated communications signal1250. The front end module1208may be implemented using the conventional front end module300, the conventional front end module400, the conventional front end module500, the front end module600, the front end module1000, any other suitable front end module that is capable of processing the translated communications signal1250to the digital representation that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention, or portions and/or combinations thereof.

The demodulator module1212demodulates the digital sequences of data250.1through250.nusing any suitable analog or digital demodulation technique for any suitable modulation technique such as amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), phase shift keying (PSK), frequency shift keying (FSK), amplitude shift keying (ASK), quadrature amplitude modulation (QAM) and/or any other suitable demodulation technique that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present invention to provide demodulated sequences of data252.1through252.n. Additionally, the demodulator module1212may decode the digital sequences of data250.1through250.naccording to a multiple access transmission scheme such as code division multiple access (CDMA), synchronous CDMA (S-CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), discrete multi-tone (DMT) modulation, orthogonal frequency division multiple access (OFDMA) and/or any other suitable multiple access scheme that will be apparent by those skilled in the relevant art(s). The demodulator module1212uses the one or more communications receiver parameters1254to substantially reduce the phase noise of the local oscillator generator module1206that is present within the digital sequences of data250.1through250.n.

CONCLUSION