Compression of baseband signals in base transceiver systems
First Claim
1. A base transceiver system, comprising:
- a base station processor, an RF unit, and a data transfer link between the base station processor and the RF unit;
the RF unit being connected to the data transfer link, and to an antenna to receive an analog uplink signal having one or more carriers, the RF unit being configured to translate each of said one or more carriers from the analog uplink signal into one or more uplink digital baseband antenna-carrier channels, each uplink digital baseband antenna-carrier channel having a sequence of uplink signal samples that are sent to the data transfer link, wherein each uplink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, and the RF unit also being configured to translate one or more downlink digital baseband antenna-carrier channels received from the data transfer link and having a sequence of downlink signal samples, wherein each downlink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, into an analog downlink signal having one or more carriers for transmission by an antenna;
the base station processor being connected to the data transfer link, and including a communication interface adapted for connection to a source of downlink signals, and to a destination for uplink signals, the base station processor being configured to translate the downlink signal from the communications interface to one or more downlink digital baseband antenna-carrier channels and having a sequence of downlink signal samples, wherein each downlink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, and to transmit the sequence of downlink digital baseband antenna-carrier channels across the data transfer link to the RF unit, and to process one or more uplink digital baseband antenna-carrier channels received from the RF unit across the data transfer link to produce uplink data for delivery across the communications interface; and
further includingcompression and decompression logic at the RF unit and at the base station processor arranged for transfer of compressed versions of the uplink and downlink digital baseband antenna-carrier channels across the data transfer link.
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Accused Products
Abstract
A signal compression method and apparatus for a base transceiver system (BTS) in a wireless communication network provides efficient transfer of compressed signal samples over serial data links in the system. For the uplink, an RF unit of the BTS compresses baseband signal samples resulting from analog to digital conversion of a received analog signal followed by digital downconversion. The compressed signal samples are transferred over the serial data link to the baseband processor then decompressed prior to normal signal processing. For the downlink, the baseband processor compresses baseband signal samples and transfers the compressed signal samples to the RF unit. The RF unit decompresses the compressed samples prior to digital upconversion and digital to analog conversion to form an analog signal for transmission over an antenna. Compression and decompression can be incorporated into operations of conventional base stations and distributed antenna systems, including OBSAI or CPRI compliant systems.
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Citations
41 Claims
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1. A base transceiver system, comprising:
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a base station processor, an RF unit, and a data transfer link between the base station processor and the RF unit; the RF unit being connected to the data transfer link, and to an antenna to receive an analog uplink signal having one or more carriers, the RF unit being configured to translate each of said one or more carriers from the analog uplink signal into one or more uplink digital baseband antenna-carrier channels, each uplink digital baseband antenna-carrier channel having a sequence of uplink signal samples that are sent to the data transfer link, wherein each uplink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, and the RF unit also being configured to translate one or more downlink digital baseband antenna-carrier channels received from the data transfer link and having a sequence of downlink signal samples, wherein each downlink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, into an analog downlink signal having one or more carriers for transmission by an antenna; the base station processor being connected to the data transfer link, and including a communication interface adapted for connection to a source of downlink signals, and to a destination for uplink signals, the base station processor being configured to translate the downlink signal from the communications interface to one or more downlink digital baseband antenna-carrier channels and having a sequence of downlink signal samples, wherein each downlink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, and to transmit the sequence of downlink digital baseband antenna-carrier channels across the data transfer link to the RF unit, and to process one or more uplink digital baseband antenna-carrier channels received from the RF unit across the data transfer link to produce uplink data for delivery across the communications interface; and
further includingcompression and decompression logic at the RF unit and at the base station processor arranged for transfer of compressed versions of the uplink and downlink digital baseband antenna-carrier channels across the data transfer link. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A base transceiver system, comprising:
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a base station processor, a plurality of antenna nodes, and a data transfer network connected to the base station processor and the plurality of antenna nodes; each of the plurality of antenna nodes including an antenna and an RF unit connected to the antenna, the RF unit arranged to receive an analog uplink signal having one or more carriers, the RF unit being configured to translate each of said one or more carriers from the analog uplink signal into one or more uplink digital baseband antenna-carrier channels, each uplink digital baseband antenna-carrier channel having a sequence of uplink signal samples that are sent to the data transfer network, wherein each uplink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, and the RF unit also being configured to translate one or more downlink digital baseband antenna-carrier channels received from the data transfer network and having a sequence of downlink signal samples, wherein each downlink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, into an analog downlink signal having one or more carriers for transmission by an antenna; the base station processor being connected to the data transfer network, and including a communication interface adapted for connection to a source of downlink signals, and to a destination for uplink signals, the base station processor being configured to translate the downlink signal from the communications interface to a plurality of downlink digital baseband antenna-carrier channels each having a sequence of downlink signal samples, wherein each downlink signal sample includes an in-phase (I) sample and a quadrature (Q) sample, and to transmit the sequences of downlink digital baseband antenna-carrier channels across the data transfer network to RF units of the plurality of antenna nodes, and to process one or more uplink digital baseband antenna-carrier channels received from the plurality of antenna nodes across the data transfer network to produce uplink data for delivery across the communications interface; and
further includingcompression and decompression logic at the RF units of the plurality of antenna nodes and at the base station processor arranged for transfer of compressed versions of the uplink and downlink digital baseband antenna-carrier channels across the data transfer network. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. 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, and 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 to form compressed samples in accordance with a compression control parameter, wherein each compressed sample includes a compressed I sample and a compressed Q sample; formatting the compressed samples for transfer over the serial data link; transferring the compressed samples over the serial data link from the RF unit to the baseband processor; receiving the compressed samples at the baseband processor; decompressing the compressed samples corresponding to each baseband channel in accordance with a decompression control parameter to form 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 (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification