Patent Grant
9369149
Transceiver systems in wireless communication networks perform the control functions for directing signals among communicating subscribers, or terminals, as well as communication with external networks. The general operations of a radio transceiver system include receiving radio frequency (RF) signals, converting them to signal data, performing various control and signal processing operations on the signal data, converting the signal data to an RF signal and transmitting the RF signal to the wireless subscriber. Transceiver systems in wireless communications networks include radio base stations and distributed antenna systems (DAS). For the reverse link, or uplink, a terminal transmits the RF signal received by the transceiver system. For the forward link, or downlink, the transceiver system transmits the RF signal to a subscriber, or terminal, in the wireless network. A terminal may be fixed or mobile wireless user equipment unit (UE) and may be a wireless device, cellular phone, personal digital assistant (PDA), personal computer or other device equipped with a wireless modem.
The rapid increase in data (e.g., video) communication and content consumption has led to expansion of wireless communication networks. As a result, the introduction of next generation communication standards (e.g., 3GPP LTE-A, IEEE 802.16m) has led to improved techniques for data processing, such as carrier aggregation (e.g., 100 MHz) with 8×8 MIMO (Multiple-Input, Multiple-Output) and CoMP (Cooperative Multi-Point). This in turn has created the need for radio access networks capable of handling wider bandwidths and an increasing number of antennas. These radio access networks will require a higher numbers of fiber links to connect the base stations to the remote radio units. In addition, it is desirable to provide carrier aggregation with Multiple-Input and Multiple-Output (MIMO) and Co-operative Multipoint (CoMP) techniques to significantly increase spectral efficiency. The implementation of Co-Operative Multi-point techniques requires communication between baseband units and enables load balancing for the communication system.
Modern communication systems require an increasing number of optical or copper ports and links between the baseband units and the radio units to support the various protocols and they often require a large number of discrete devices and signal routing traces to support the improved architectures. However, the improved architectures may not scale due to input and output bottlenecks. The large number of discrete devices and signal routing may also increase the cost of the device. Additionally, innovative device architectures will be required to support the increased clock frequency operation and the larger number of processing functions to efficiently process uplink, feedback and downlink data in addition to the required control signals. To support remote monitoring, debugging, control and management, such devices will also need to support a large amount of data storage.
Accordingly, there is a need for a method and apparatus that will allow for an increasing number of antennas at the radio unit as well as implementation of MIMO, CoMP and load balancing, while reducing power consumption and cost of the device. Also, there is a need for a method and apparatus that will provide these features while reducing the number of discrete devices.
The present invention provides a method and apparatus that will allow for an increasing number of antennas at the radio unit as well as implementation of MIMO, CoMP and load balancing, while reducing power consumption and cost of the baseband unit of the communication network. The present invention additionally provides a method and apparatus that will provide these features while reducing the number of discrete devices in the baseband unit.
The method and apparatus of the present invention provides for reduced power consumption and cost while supporting wide bandwidth signals from a large number of antennas, as is required by next generation systems.
A method and apparatus are disclosed in which compressed signals from remote radio units are sent directly to the switch instead of to a separate CPRI device. Thereby, the local input and output bottleneck within processing devices is removed in the data path of the signals between the remote radio units and the baseband unit. This also reduces the number of ports in the switch and bandwidth requirement for the switch. By eliminating a separate CPRI device and transmitting signals directly to the switch, it is possible to perform simpler load balancing and easier traffic migration directly from the switch instead of going through another device which could create local I/O bottleneck. This further allows easier scalability, more efficient baseband resource allocation and utilization depending on the network load.
In a particular embodiment for a communication system operating in an uplink mode, a method for processing data in a baseband unit of a communication system may include, receiving compressed data at a switch of a baseband unit, wherein the compressed data is received from at least one radio unit and operating the switch to distribute the compressed data to one of a plurality of baseband processing cards of the baseband unit. The method may further include, decompressing the compressed data at one of the plurality of baseband processing cards. In an alternative embodiment, the method may include operating the switch to decompress the compressed data and to distribute the decompressed data to one of the plurality of baseband processing cards.
In an additional embodiment for a communication system operating in a downlink mode, a method for processing data in a baseband unit of a communication system may include, receiving data at one of a plurality of baseband processing cards of a baseband unit, wherein the data is received from a communication backhaul, compressing the data at the one of the plurality of baseband processing cards and transmitting the compressed data to a switch of the baseband unit. In an alternative embodiment, the method may include transmitting the data to a switch of the baseband unit without compressing the received data and compressing the data at the switch of the baseband unit and decompressing the data at the switch.
The switch may be located on one of the plurality of baseband cards of the baseband unit or alternatively, the switch may be located on one of a plurality of switch cards of the baseband unit.
The compressed data may be received at the switch of the baseband unit from a wired connection or a wireless connection from at least one radio unit.
The switch may perform protocol conversion of the compressed data at the baseband unit. Additionally, the switch may perform load-balancing of the compressed data through the switch of the baseband unit.
In an additional embodiment, an apparatus for processing data in a baseband unit of a communication system may include at least one computation processor of a baseband unit and a switch coupled to the at least one computation processor. The switch may be configured to receive compressed data from at least one radio unit and to distribute the compressed data to one of the at least one computation processors. In an alternative embodiment, the switch may be configured to decompress the compressed data prior to distributing the decompressed data to one of the at least one computation processors.
In another embodiment, an apparatus for processing data in a baseband unit of a communication system may include a switch of a baseband unit and at least one computation processor coupled to the switch. The computation processor may be configured to receive data from a backhaul connection and to compress the data prior to transmitting the data to the switch. In an alternative embodiment, the computation processor may be configured to transmit the data to the switch without compressing the data. The switch may then be configured to compress the data prior to transferring the data to the radio units.
The modular design approach for radio transceiver systems, wherein the baseband processing is separated from the radio frequency processing, has led the industry to develop interface standards. One example of a standard interface for the data transfer interfaces between the radio units and baseband units of transceiver systems is the Common Public Radio Interface (CPRI). Connection topologies between the baseband unit and one or more remote radio units include point-to-point, multiple point-to-point, chain, star, tree, ring and combinations thereof. Another example of an interface specification for modular architecture of radio transceiver systems is the Open Base Station Architecture Initiative (OBSAI). The OBSAI specification describes alternative protocols for the interconnection of and baseband modules and remote radio units analogous to the CPRI specification, as well as data transfer protocols for the serial data links.
In conventional cellular communication systems, radio coverage is provided for a given geographic area via multiple base stations distributed throughout the geographic area involved. In this way, each base station can serve traffic in a smaller geographic area. Consequently, multiple base stations in a wireless communication network can simultaneously serve users in different geographic areas, which increases the overall capacity of the wireless network involved.
In order to further increase the capacity of wireless systems further, each base station may be configured to support radio coverage in multiple sectors. For example, a base station in a conventional cellular system may be configured to provide radio coverage in one sector, three sectors or six sectors. In those systems employing multiple sectors per base station, each sector can handle part of the traffic in an additional smaller geographic area, which increases the overall capacity of the wireless network involved. Each of the sectors may include multiple remote radio units in communication with each of the base stations. Each of the radio units may further include multiple antennas for both receiving and transmitting data between the radio unit and the user of the communication system.
As described, communication systems are known in the art to include a baseband unit for performing signal processing in communication with a remote radio unit for receiving and transmitting signals to an antenna. The present invention provides a method and apparatus for an efficient processing solution implemented in the baseband unit of a communication system.
With reference to
In the embodiments illustrated in
When operating in an uplink mode, the data from the remote radio units 125, 135, 145 and the data from the small cell remote radio units 220, 225 is compressed prior to being transmitted directly to the switch 190 of the baseband unit. The switch 190 may then be operated to distribute the compressed data to one of the baseband processing cards 185. The computation processors 195 of the baseband processing card may then be used to further process the received data and to decompress the data prior to distribution over the backhaul 215. As such, in the present invention, the compressed data from the remote radio units is sent directly to the switch 190 without first being decompressed by an intermediate device such as a CPRI device or other digital signal processing device. In this way, the port count of the switch 190 can be reduced because the switch 190 is responsible for distributing compressed data instead of decompressed data. Additionally, the switch 190 can run at a lower speed when distributing the compressed data as compared to the decompressed data, thereby reducing the power consumption of the baseband unit.
In an alternative embodiment, the data received from the remote radio units may be decompressed at the switch 190 prior to being distributed to the computation processor 195. In this embodiment, the power consumption of the switch 190 may not be reduced, but the on-chip switch core bandwidth may still be reduced.
The switch 190 may also be operated to distribute the compressed data to the network storage or server card 115 through switch 240. By distributing compressed data, instead of decompressed data, to the network storage or server card 115, the storage capacity of the network storage or server card 115 may be increased.
In the embodiment illustrated in
In an additional embodiment of the present invention, illustrated with reference to
In accordance with the embodiment illustrated with reference to
In a downlink mode, the system illustrated with reference to
With reference to
In accordance with the embodiment illustrated with reference to
In a downlink mode, the system illustrated with reference to
With reference to
If it is determined that the switch will not perform the decompression, the compressed data may be distributed to one of a plurality of baseband processing cards 320 through the switch. The compressed data may then be decompressed at the baseband processing card 335 and then further processed by the computation processor of the baseband processing card 340. Alternatively, if it is determined that the switch will perform the decompression, the compressed data may be distributed through the switch 325 and then the compressed data may be decompressed prior to exiting the switch 330. The decompressed data may then be transmitted from the switch to one of the baseband processing cards for further processing 340.
After the data has been either decompressed by the switch 330 or by one of the baseband processing cards 335, it may then be determined whether or not the processing of the data is complete 355. If the processing of the data is complete, the decision is made as to whether or not to locally store the data 365. If the data is to be stored, the data may be compressed at one of the plurality of baseband processing cards 370 and distributed to one of a plurality of network storage or server cards through the switch 375. The distributed data may then be decompressed at one of the plurality of network storage or server cards and stored locally 380 for subsequent access. In addition to locally storing the data, the data may also be transmitted to a backhaul interface 360. If the processing of the data is not complete 355, it may then be determined whether or not the switch will perform the compression of the data 350 prior to further processing of the data. If the switch is to perform the compression, the data will be compressed at the ingress to the switch 345, prior to distributing the data to one of the plurality of baseband processing cards through the switch 320. Alternatively, if it is determined that the switch will not perform the compression, the data may be compressed by of the plurality of baseband processing cards 385 prior to distributing the data through the switch 320.
With reference to
With reference to
If it is determined that the switch will not perform the data compression, the data may be compressed at one of the plurality of baseband processing cards 430 prior to transmitting the compressed data to the switch 435. Protocol conversion may then be performed in the switch 440 if necessary. After any necessary protocol conversion has been performed 440, the compressed data may be distributed to one or more baseband processing units, or server or storage units for further processing 445. Alternatively, if it is determined that the switch will perform the data compression, the switch may compress the data 415 and perform any necessary protocol conversion 420 of the data. The switch may then distribute the data to one or more baseband processing units for further processing 445.
Upon receiving the compressed data from either the switch or one of the baseband processing units, the baseband processing unit may decompress the data and perform additional processing on the data 450. If it is then determined that the processing of the data is not complete 475, the determination of whether or not to compress the data in the switch 455 prior to further processing can be made. If it is determined that the switch will perform the compression, the data requiring additional processing may be transmitted to the switch for subsequent compression 415 and distribution 425. Alternatively, if it is determined that the switch will not perform the compression, the data requiring additional processing may be transmitted to one of the plurality of baseband processing cards for subsequent compression 430 and distribution 445. Alternatively, if it is determined that the processing is complete 475, a decision may be made regarding the storage of the data 470. If the data is to be stored locally, the data may be compressed at the switch or at one or more of the baseband processing units and stored locally for subsequent retrieval 460. In addition to storing the data, the data may also be compressed at the switch or at one or more of the baseband processing units and distributed through the switch to at least one radio unit over a wired or wireless interface 465.
With reference again to
In the proposed architecture in the uplink, the signal from the radio is directly sent to the switch instead of separate CPRI device or SOC/ASIC/FPGA/DSP. This method eliminates any local I/O bottleneck within processing device that is in the data path. The proposed system and method also allows easier scalability, more efficient resource utilization as well as simpler load balancing through traffic migration.
Decompression of the signal could also be performed at the switch. In embodiments in which decompression of the signal is performed at the switch, the switch is an integrated circuit device formed on a single semiconductor die that includes a decompression module that is operable to selectively decompress incoming signal data as required by its routing instructions and programming of the switch.
Decompression of the signal could also be performed at the baseband processing devices or at the remote radio units.
The architecture supports either of the protocols (S-RIO/CPRI/Ethernet) over wired or wireless medium. The proposed solution includes compression/decompression at the baseband card either in the SOC/ASIC/FPGA/DSP or in the switches. When included in SOC/ASIC/FPGA/DSP, the switch bandwidth, port count, SERDES count, number of routing on the board could be reduced. When included in the switch, the switch core throughput could be reduced. Either way, power consumption, cost, and routing are reduced at the baseband side.
The system and method of the present invention supports better system and device level approaches for load balancing and CoMP for wide bandwidth signals having a large number of antennas. The proposed approach significantly reduces infrastructure cost (baseband units and radio units) by reducing fiber links as well as by optimizing resources. The methods and apparatus of the present invention allows interconnect devices to effectively process higher bandwidth signals even with lower port rates (e.g., support 80 G with 40 G port using 2:1 compression).
The radio unit processing and control module and distributed switch of the present invention supports load balancing and CoMP for wide bandwidth signals employing a large number of antennas. In addition, the radio unit processing and control module and distributed switch of the present invention reduces infrastructure cost (baseband and Radio) by reducing fiber links. The method and apparatus of the present invention allows interconnect devices to effectively process higher bandwidth signals even with lower port rates (e.g., support 80 G with 40 G port using 2:1 compression).
Though the radio unit processing and control module and distributed switch of the present invention is designed for use with next generation architecture that includes load-balancing and pooled baseband, in other embodiments, the radio unit processing and control module and distributed switch is adapted to be used in existing network architectures that do not include load balancing or pooled baseband.
As is known in the art, the radio unit processing and control module and distributed switch architecture may be implemented in a Field Programmable Gate Array (FPGA), an Application-Specific Integrated Circuit (ASIC) or a variety of other commonly known integrated circuit devices. The implementation of the invention may include both hardware and software components.
This application claims priority to U.S. Provisional Patent Application No. 61/642,322 filed on May 3, 2012 entitled, “Efficient Signal Chain Processing for Communication Systems” and to U.S. Provisional Patent Application No. 61/642,424 filed on May 3, 2012 entitled, “Method and Apparatus for Efficient Radio Processing in Communication Systems.” This application is related to the patent application titled “Method and Apparatus for efficient Radio Unit Processing in a Communication System,” by Mohammad Shahanshah Akhter and Brian Scott Darnell, filed on even date herewith, that is hereby incorporated by reference in its entirety.
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