FREQUENCY DOMAIN COMPRESSION IN A BASE TRANSCEIVER SYSTEM
First Claim
1. In a base transceiver system of a wireless communication network, a method for transferring signal data from a radio frequency (RF) unit to a baseband processor over a serial data link, wherein the RF unit is connected to an antenna to receive an analog signal, the analog signal representing a plurality of antenna-carrier channels, the RF unit including an analog to digital converter (ADC) that converts the analog signal to a digital signal and a digital down converter (DDC) that downconverts the digital signal to a plurality of baseband channels, each baseband channel corresponding to one of the antenna-carrier channels and having a sequence of signal samples, wherein each signal sample includes an in-phase (I) sample and a quadrature (Q) sample, wherein the baseband processor performs signal processing operations on the signal samples received from the RF unit, the method comprising:
- compressing the signal samples of each baseband channel at the RF unit, wherein for each baseband channel the compressing comprises;
computing a frequency domain transform of a plurality of the signal samples of each baseband channel at the RF unit to form a plurality of frequency domain coefficients, wherein the frequency domain coefficients include a real component and an imaginary component for each of a plurality of frequency bins;
attenuating one or more of the frequency domain coefficients in accordance with an attenuation profile to form a plurality of attenuated coefficients, wherein the attenuation profile specifies attenuation levels corresponding to the frequency bins; and
encoding the attenuated coefficients to form compressed coefficients;
formatting the compressed coefficients of the plurality of baseband channels for transfer over the serial data link;
transferring the compressed coefficients over the serial data link from the RF unit to the baseband processor;
receiving the compressed coefficients at the baseband processor; and
decompressing the compressed coefficients at the baseband processor, wherein for each baseband channel the decompressing comprises;
decoding the compressed coefficients to form reconstructed attenuated coefficients;
amplifying a plurality of the reconstructed attenuated coefficients in accordance with a gain profile to form a plurality of decompressed coefficients corresponding to each baseband channel, wherein the gain profile corresponds to the attenuation profile and specifies gain levels for corresponding frequency bins; and
computing an inverse frequency domain transform of the plurality of decompressed coefficients to form a plurality of decompressed signal samples of the corresponding baseband channel, wherein each decompressed signal sample includes a decompressed I sample and a decompressed Q sample, wherein the baseband processor applies the signal processing operations to the decompressed signal samples for each baseband channel.
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Accused Products
Abstract
A method and apparatus provide signal compression for transfer over serial data links in a base transceiver system (BTS) of a wireless communication network. For the uplink, an RF unit of the BTS applies frequency domain compression of baseband signal samples, resulting from analog to digital conversion of received analog signals followed by digital downconversion, forming compressed coefficients. After transfer over the serial data link, the baseband processor then applies frequency domain decompression to the compressed coefficients prior to normal signal processing. For the downlink, the baseband processor applies frequency domain compression of baseband signal samples and transfers the compressed coefficients to the RF unit. The RF unit applies frequency domain decompression to the compressed coefficients prior to digital upconversion and digital to analog conversion, generating the analog signal for transmission over the antenna. This abstract does not limit the scope of the invention as described in the claims.
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Citations
90 Claims
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1. In a base transceiver system of a wireless communication network, a method for transferring signal data from a radio frequency (RF) unit to a baseband processor over a serial data link, wherein the RF unit is connected to an antenna to receive an analog signal, the analog signal representing a plurality of antenna-carrier channels, the RF unit including an analog to digital converter (ADC) that converts the analog signal to a digital signal and a digital down converter (DDC) that downconverts the digital signal to a plurality of baseband channels, each baseband channel corresponding to one of the antenna-carrier channels and having a sequence of signal samples, wherein each signal sample includes an in-phase (I) sample and a quadrature (Q) sample, wherein the baseband processor performs signal processing operations on the signal samples received from the RF unit, the method comprising:
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compressing the signal samples of each baseband channel at the RF unit, wherein for each baseband channel the compressing comprises; computing a frequency domain transform of a plurality of the signal samples of each baseband channel at the RF unit to form a plurality of frequency domain coefficients, wherein the frequency domain coefficients include a real component and an imaginary component for each of a plurality of frequency bins; attenuating one or more of the frequency domain coefficients in accordance with an attenuation profile to form a plurality of attenuated coefficients, wherein the attenuation profile specifies attenuation levels corresponding to the frequency bins; and encoding the attenuated coefficients to form compressed coefficients; formatting the compressed coefficients of the plurality of baseband channels for transfer over the serial data link; transferring the compressed coefficients over the serial data link from the RF unit to the baseband processor;
receiving the compressed coefficients at the baseband processor; anddecompressing the compressed coefficients at the baseband processor, wherein for each baseband channel the decompressing comprises; decoding the compressed coefficients to form reconstructed attenuated coefficients; amplifying a plurality of the reconstructed attenuated coefficients in accordance with a gain profile to form a plurality of decompressed coefficients corresponding to each baseband channel, wherein the gain profile corresponds to the attenuation profile and specifies gain levels for corresponding frequency bins; and computing an inverse frequency domain transform of the plurality of decompressed coefficients to form a plurality of decompressed signal samples of the corresponding baseband channel, wherein each decompressed signal sample includes a decompressed I sample and a decompressed Q sample, wherein the baseband processor applies the signal processing operations to the decompressed signal samples for each baseband channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 84, 87)
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17. In a base transceiver system of a wireless communication network, a method for transferring signal samples from a baseband processor to a radio frequency (RF) unit over a serial data link, each signal sample associated with one of a plurality of baseband channels, wherein each signal sample includes an in-phase (I) sample and a quadrature (Q) sample, the RF unit including a digital up converter (DUC) that upconverts a sequence of signal samples of each baseband channel to a corresponding one of a plurality of antenna-carrier channels to form a single upconverted digital signal and a digital to analog converter (DAC) that converts the upconverted digital signal to an analog signal, wherein the RF unit is coupled to an antenna to transmit the analog signal, the analog signal representing the plurality of antenna-carrier channels, the method comprising:
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compressing the signal samples of each baseband channel at the baseband processor, wherein for each baseband channel the compressing comprises; computing a frequency domain transform of a plurality of the signal samples of each baseband channel to form a plurality of frequency domain coefficients, wherein the frequency domain coefficients include a real component and an imaginary component for each of a plurality of frequency bins; attenuating one or more of the frequency domain coefficients in accordance with an attenuation profile to form a plurality of attenuated coefficients, wherein the attenuation profile specifies attenuation levels corresponding to the frequency bins; and encoding the attenuated coefficients to form compressed coefficients;
the method further comprising;formatting the compressed coefficients of the plurality of baseband channels for transfer over the serial data link; transferring the compressed coefficients over the serial data link from the baseband processor to the RF unit; receiving the compressed coefficients at the RF unit; and decompressing the compressed coefficients at the RF unit, wherein for each baseband channel the decompressing comprises; decoding the compressed coefficients to form reconstructed attenuated coefficients; amplifying a plurality of the reconstructed attenuated coefficients in accordance with a gain profile to form a plurality of decompressed coefficients corresponding to each baseband channel, wherein the gain profile corresponds to the attenuation profile and specifies gain levels for corresponding frequency bins; and computing an inverse frequency domain transform of the plurality of decompressed coefficients to form a plurality of decompressed signal samples of the corresponding baseband channel, wherein each decompressed signal sample includes a decompressed I sample and a decompressed Q sample, wherein the decompressed signal samples are provided to the DUC for forming the upconverted digital signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. In a base transceiver system of a wireless communication network, including a radio frequency (RF) unit coupled to an antenna to receive an analog signal and a baseband processor coupled to the RF unit by a serial data link, the analog signal representing a plurality of antenna-carrier channels, the RF unit including an analog to digital converter (ADC) that converts the analog signal to a digital signal and a digital down converter (DDC) that downconverts the digital signal to a plurality of baseband channels, each baseband channel corresponding to one of the antenna-carrier channels and having a sequence of signal samples, wherein each signal sample includes an in-phase (I) sample and a quadrature (Q) sample, wherein the baseband processor performs signal processing operations on the signal samples received from the RF unit, an apparatus for data transfer from the RF unit to the baseband processor over the serial data link, the apparatus comprising:
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a plurality of compressors at the RF unit, each compressor coupled to receive the signal samples of a corresponding baseband channel output from the DDC, each of the plurality of compressors comprising; logic to compute a frequency domain transform of a plurality of the signal samples of the corresponding baseband channel to form a plurality of frequency domain coefficients, wherein the frequency domain coefficients include a real component and an imaginary component for each of a plurality of frequency bins; an attenuator to adjust the frequency domain coefficients in accordance with an attenuation profile to form a plurality of attenuated coefficients, wherein the attenuation profile specifies attenuation levels corresponding to the frequency bins, wherein the attenuation profile is stored in a first memory coupled to the attenuator; and an encoder coupled to the attenuator to encode the attenuated coefficients to form compressed coefficients; a formatter coupled to the plurality of compressors to format the compressed coefficients of the plurality of baseband channels in accordance with a data transfer protocol; the serial data link coupled to the formatter for transferring the compressed coefficients to the baseband processor; the baseband processor coupled to the serial data link to receive the compressed coefficients; and a plurality of decompressors at the baseband processor, each decompressor receiving the compressed coefficients of the corresponding baseband channel, each of the plurality of decompressors comprising; a decoder to decode the compressed coefficients to form reconstructed attenuated coefficients; an amplifier coupled to the decoder to increase magnitudes of a plurality of the reconstructed attenuated coefficients in accordance with a gain profile to form a plurality of decompressed coefficients, wherein the gain profile corresponds to the attenuation profile and specifies gain levels corresponding to the frequency bins, wherein the gain profile is stored in a second memory coupled to the amplifier; and logic coupled to the amplifier to compute an inverse frequency domain transform of the plurality of decompressed coefficients to form a plurality of decompressed signal samples of the corresponding baseband channel, wherein each decompressed signal sample includes a decompressed I sample and a decompressed Q sample, wherein the baseband processor applies the signal processing operations to the decompressed signal samples for each baseband channel. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 85, 88)
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49. In a base transceiver system of a wireless communication network, including a radio frequency (RF) unit coupled to an antenna to transmit an analog signal and a baseband processor coupled to the RF unit by a serial data link, the baseband processor providing a plurality of signal samples to the RF unit, each signal sample associated with one of a plurality of baseband channels, wherein each signal sample includes an in-phase (I) sample and a quadrature (Q) sample, the RF unit including a digital up converter (DUC) that upconverts a sequence of signal samples of each baseband channel to a corresponding one of a plurality of antenna-carrier channels to form a single upconverted digital signal and a digital to analog converter (DAC) that converts the upconverted digital signal to the analog signal, the analog signal representing the plurality of antenna-carrier channels, an apparatus for data transfer from the baseband processor to the RF unit, the apparatus comprising:
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a plurality of compressors at the baseband processor, each compressor compressing signal samples of a corresponding baseband channel, each of the plurality of compressors comprising; logic to compute a frequency domain transform of a plurality of the signal samples of the corresponding baseband channel to form a plurality of frequency domain coefficients, wherein the frequency domain coefficients include a real component and an imaginary component for each of a plurality of frequency bins; an attenuator to adjust the frequency domain coefficients in accordance with an attenuation profile to form a plurality of attenuated coefficients, wherein the attenuation profile specifies attenuation levels corresponding to the frequency bins, wherein the attenuation profile is stored in a first memory coupled to the attenuator; and an encoder coupled to the attenuator to encode the attenuated coefficients to form compressed coefficients; a formatter coupled to the plurality of compressors to format the compressed coefficients in accordance with a data transfer protocol; the serial data link coupled to the formatter for transferring the compressed coefficients to the RF unit; the RF unit coupled to the serial data link to receive the compressed coefficients; and a plurality of decompressors at the RF unit, each decompressor receiving the compressed coefficients of the corresponding baseband channel, each of the plurality of decompressors comprising; a decoder to decode the compressed coefficients to form reconstructed attenuated coefficients; an amplifier coupled to the decoder to increase magnitudes of a plurality of the reconstructed attenuated coefficients in accordance with a gain profile to form a plurality of decompressed coefficients, wherein the gain profile corresponds to the attenuation profile and specifies gain levels corresponding to the frequency bins, wherein the gain profile is stored in a second memory coupled to the amplifier; and logic coupled to the amplifier to compute an inverse frequency domain transform of the plurality of decompressed coefficients to form a plurality of decompressed signal samples of the corresponding baseband channel, wherein each decompressed signal sample includes a decompressed I sample and a decompressed Q sample, wherein the decompressed signal samples are provided to the DUC for forming the upconverted digital signal. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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65. A base transceiver system for a wireless communication network, the base transceiver system comprising:
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a baseband processor; a plurality of radio frequency (RF) units coupled to the baseband processor by data links; and circuitry implementing frequency domain compression over the data links between the RF units and the baseband processor. - View Dependent Claims (66, 67)
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68. An integrated circuit device for compressing signal data for transmission over a serial data link in a base transceiver system of a wireless communication network, the integrated circuit device comprising:
a plurality of compressors, each of the plurality of compressors to receive a plurality of signal samples representative of the signal data of a corresponding baseband channel, each of the plurality of compressors comprising; a frequency transform unit to compute a frequency domain transform of the plurality of signal samples to generate a plurality of frequency domain coefficients for each of a plurality of frequency bins; an attenuator coupled to the frequency transform unit, the attenuator to adjust the plurality of frequency domain coefficients in accordance with an attenuation profile to generate a plurality of attenuated coefficients, wherein the attenuation profile specifies attenuation levels corresponding to the plurality of frequency bins; and an encoder coupled to the attenuator, the encoder to encode the attenuated coefficients to form a plurality of compressed coefficients for transmission over the serial data link. - View Dependent Claims (69, 70, 71, 72, 73, 74, 75, 76, 77, 86, 89)
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78. An integrated circuit device for decompressing a plurality of compressed coefficients received over a serial data link in a base transceiver system of a wireless communication network, the integrated circuit device comprising:
a plurality of decompressors, each of the plurality of decompressors to receive a plurality of compressed coefficients of a corresponding baseband channel, each of the plurality of decompressors comprising; a decoder to decode the plurality of compressed coefficients to form a plurality of reconstructed attenuated coefficients; an amplifier coupled to the decoder, the amplifier to increase a magnitude of at least one of the plurality of reconstructed attenuated coefficients in accordance with a gain profile to form a plurality of decompressed coefficients, wherein the gain profile corresponds to an attenuation profile associated with the plurality of compressed coefficients and the gain profile specifies gain levels corresponding to a plurality of frequency bins of the compressed coefficients; and an inverse frequency domain transform unit coupled to the amplifier, the inverse frequency domain transform unit to compute an inverse frequency transform of the plurality of decompressed coefficients to generate a plurality of decompressed signal samples of the corresponding baseband channel. - View Dependent Claims (79, 80, 81, 82, 83, 90)
Specification