KR20070021133A - Multiple use of a standard interface in a device - Google Patents

Abstract

The present invention provides data between at least one first unit (BB1, BB2), the first unit (BB1, BB2) and the second unit (BB1, BB2) functionally identical to the first unit (BB1, BB2). A first interface CPRI for transmitting and a second for transmitting data between the first units BB1 and BB2 and the third units RE1 and RE2 functionally different from the first units BB1 and BB2. An apparatus comprising an interface (CPRI). The first and second interfaces CPRI are implemented such that multiple types of data can be transmitted respectively. Two interfaces are specified according to the same standard.

Description

MULTIPLE USE OF A STANDARD INTERFACE IN A DEVICE}

The present invention provides a first interface for transferring data between a first unit and a second unit that is functionally identical to the first unit, and transfers data between the first unit and a third unit that is functionally different from the first unit. A device having a second unit for doing so. The invention also relates to a method for operating such a device.

The interfaces are used for the connection between two or more units of one or more devices, and data can be transferred between the units connected via the interface. Referring to the physical layer, the interface may be implemented by, for example, a cable or line, through which data is transmitted using electrical or optical transmission methods. The interface is defined in particular by the transmission protocols and transmission methods used for communication between the connected units. Transport protocol refers to an established method for data exchange between two units connected via an interface; The transport protocol includes conventions containing data formats and control procedures defined for communication. Transport protocols according to the Open Systems Interconnection (OSI) layer model are examples of a group of transport protocols.

For example, the structure or definition of an interface, which can be specified according to a standard, usually depends on the characteristics of the units connected by the interface, and therefore it is generally not possible to connect indiscriminate units via a particular interface. not.

The various units connected together via suitable interfaces are also in the base station of wireless communication systems. Base stations typically include multiple units for baseband processing, where data to or from subscriber stations is processed within entities for baseband processing. There are also transmit / receive units which modulate the baseband data provided by baseband processing on carrier frequencies and transmit it to subscriber stations. The connection between the unit for baseband processing and the transmit / receive unit is for example the CPRI standard (now CPRI Specification V1.0 (2003-09-30), Common Public Radio Interface (CPRI); http: // www. It can be made through the interface according to the Interface Specification (available through cpri.info/ ).

In particular for the wireless standard Universal Mobile Telecommunications System (UMTS), it is advisable to add data from multiple subscriber stations in the transmission direction, perhaps data processed by different entities for baseband processing, before transmitting to the relevant transmission unit. It may be necessary, or it may be necessary to distribute data received in a receiving direction by a transmitting / receiving unit located in a plurality of entities for baseband processing. In order to achieve this, one unit executing partial steps for baseband processing in base stations is usually connected in a star form to a number of units that are functionally different from the first-mentioned unit, so that other units of baseband processing Perform partial steps.

The present invention corrects the problem of describing an efficient implementation of a device, for example a device comprising components of a base station in a wireless communication system, in which a first unit is connected with a second unit and a third unit via interfaces.

The problem is solved by an apparatus having the features of claim 1 and a method having the features of each claim.

Preferred embodiments and refinements relate to the dependent claims.

The device according to the invention comprises at least a first unit. The apparatus transmits data between a first interface for transferring data between a first unit and a second unit that is functionally identical to the first unit, and between the first unit and a third unit that is functionally different from the first unit. It has a second interface for. In the present description, the first and second interfaces are implemented such that a number of different data types can be transmitted in each case and the two interfaces are specified according to the same standard.

The second and / or third unit may be a device of the claimed or other device or a number of other devices. The functional equivalence between the first unit and the second unit does not mean that the first unit and the second unit must be configured in essentially the same way, but rather they are used to solve corresponding or similar problems reciprocally. That means you can. In addition to the connection of the first unit to the second and third units, there may be further connections of the first unit to other units that are functionally the same as or different from the first unit.

An interface refers to a material connection, eg a cable or lines, between a first unit and a second or third unit. It is possible to transmit multiple data types via the interfaces used in the present invention, different data types being for example related to the content and / or source of each of the data types and / or requirements for transmission over the interface. For example, it may vary with regard to the required data rate or time requirements related to the transmission. The data types that may be transmitted via the first interface may be different from the data types that may be transmitted via the second interface, or the data types may be the same. Both interfaces used in the present invention are specified according to a standard, and the standard related to the interface may specify or at least provide optionally transmission methods for transport protocols for the physical layer and / or higher layers, for example. have.

In an improvement of the present invention, the standard allows various data types to be transmitted using a time division multiplexing method. The standard may additionally or alternatively provide an optical and / or electronic transmission method.

According to various embodiments of the present invention, the standard provides an Ethernet protocol and / or High Data Link Control (HDLC) as the transport protocol. Protocols other than these two protocols may be provided or selected. The standard may provide an Ethernet protocol and / or an HDLC protocol used in one or more protocol layers.

In each case it is preferred if the first unit and the second unit are entities for baseband processing of radio signals. Baseband processing in the transmission direction includes, for example, encoding, spreading, scrambling, and block forming. In the receiving direction, for example, channel operations and respective reverse operations for the baseband processing in the transmission direction may be performed in the context of baseband processing.

According to an embodiment of the invention, the first unit is provided with means for processing data of the second unit that was received via the first interface. As a result, the first unit can combine its data with the data of the second unit before the data is transmitted to the third unit via the second interface.

In an improvement of the invention, the third unit is a transmitting and / or receiving entity for transmitting and / or receiving wireless signals. The third unit preferably receives such radio signals or the contents of the radio signals from a first unit, which may be implemented in the form of an entity for baseband processing for radio signals. Similarly, the third unit may transmit these wireless signals to the first unit, which may be implemented in the form of an entity for baseband processing for wireless signals. The third unit may be equipped with antennas for receiving and / or transmitting wireless signals.

It is useful when the claimed device represents at least one component of a base station in a wireless communication system.

According to an improvement of the invention, the first and second interfaces are interfaces specified according to the CPRI standard. CPRI means both current and future versions.

In a method for operating an apparatus comprising at least one first unit, data is transmitted over a first interface between a first unit and a second unit that is functionally identical to the first unit, wherein the first unit and the first unit are transmitted. Data is transmitted via the second interface between one unit and a third unit that is functionally different. A number of different data types are in each case transmitted over the first and second interfaces, the first and second interfaces being specified according to the same standard.

The above embodiments and improvements with respect to the standard and / or first unit and / or the second unit and / or the third unit will be described respectively with reference to the claimed method.

The present invention is described in more detail using the following references to exemplary embodiments.

1 shows a section of a base station according to the invention, and

2 shows a section of a base station according to the prior art;

The present invention is described below with respect to a base station of a UMTS wireless communication system, in which a common public radio interface (CPRI) interface is used. However, the invention is not limited to base stations or to the use of CPRI interfaces, so according to the invention a different standard interface allowing a number of different data types to be transmitted can be implemented within a base station or other device. It may also be used instead.

The CPRI interface utilizes electrical and / or optical transmission methods at the physical layer. Various data types are transmitted over the CPRI interface using time division multiplexing. In the case of a CPRI interface, this is the transport protocol for the second layer, in particular depending on the part of the Ethernet protocol and / or the entities connected by the High Data Link Control (HDLC) protocol and / or the related interfaces, for example. It is possible to use operator-specific transport protocols that may vary significantly. CPRI interfaces are described in the currently valid standard version of CPRI specification V1.0, the contents of which are incorporated herein by reference, and are incorporated into the specification of this patent.

For base stations in wireless communication systems, functionally different elements are divided into blocks. This modular structure provides independent scalability of functionally different elements, and as a result there are generally different numbers of blocks for elements with various functions. This division of the base station according to the prior art is shown schematically in FIG. 2. Baseband processing of subscriber data is performed in two types of modules. The module KONZ is connected in a star form with respect to three modules CHC1, CHC2 and CHC3 (CHC: Channel Card). Channel encoding in the transmission direction is performed in the modules CHC1, CHC2 and CHC3, and spreading and scrambling and addition of various subscriber baseband subscriber station data is performed in the KONZ module. Channel estimation, demodulation and decoding in the receive direction are performed in modules CHC1, CHC2, CHC3.

The module KONZ is connected to a transmit / receive unit RE, which is transmitted to and received from the modules CHC1, CHC2, CHC3 and received from the modules CHC1, CHC2, CHC3. Transmit subscriber station data, or receive subscriber station data that has been sent by the subscriber stations. In a UMTS radio communication system, when subscriber station data of multiple subscriber stations is transmitted in a radio frequency or radio frequency band through a transmit / receive unit RE in which data was processed by various modules CHC1, CHC2, CHC3, The addition of the subscriber station data which has been received from modules CHC1, CHC2, CHC3 is performed in module KONZ. Similarly, the module KONZ distributes subscriber station data received by the transmit / receive unit RE to all modules CHC1, CHC2, CHC3 which perform baseband processing for subscriber station data of the relevant frequency. . There is no connection between functionally identical modules CHC1, CHC2, CHC3.

Two baseband processing entities BB1 and BB2 are shown in FIG. 1. Each of the two baseband processing entities BB1, BB2 is preferably an element representing a combination of the two elements CHC, KONZ shown in FIG. 2. As a result, all baseband processing divided into two elements according to the prior art as shown in FIG. 2 is performed at one baseband processing entity BB1 or BB2. In this case, each baseband processing entity BB1, BB2 of the base station is connected to a shared control unit connected to a Radio Network Controller (RNC) via an interface called Iu _b in UMTS. However, the baseband processing entities BB1, BB2 may also be referred to as a Radio Equipment Controller (REC) according to the CPRI specification, in which case the units are connected to the RNC via an Iu _b interface. In the first of the two described cases, the unit REC consists of a number of baseband processing entities BB1, BB2.

The subscriber station data is transmitted to or received from the subscriber stations by the transmit / receive units RE1, RE2. In UMTS, the transmit / receive units RE1, RE2 are wirelessly connected to subscriber stations via an interface called Uu. Each transmit / receive unit RE1 or RE2 is responsible for the transmission of wireless signals in a radio frequency or frequency band and / or sector. Two baseband processing entities BB1, BB2 are connected to the transmit / receive units RE1, RE2 via an interface CPRI2 of type CPRI. Unlike the diagram of FIG. 1, also additionally or alternatively, through the same interface CPRI2 of type CPRI, the baseband processing entity BB1 is connected to the transmit / receive unit RE2 and the baseband processing entity BB2. ) May be connected to the transmit / receive unit RE1.

Various types of data are transmitted in the downlink direction, i. E. From the baseband processing entities BB1 or BB2 to the transmit / receive units RE1 or RE2 via the interfaces CPRI2:

Subscriber station data in the form of IQ data, i.e., digital payload and / or signaling data which must be transmitted to the subscriber stations via baseband processing,

Control data for control of the transmission / reception units RE1 and RE2, and

Synchronization data for synchronization of the transmit / receive units RE1, RE2.

In the receiving direction, subscriber station data received by the transmit / receive units RE1, RE2 are transmitted to the baseband processing entities BB1, BB2 for further processing via the interfaces CPRI2.

According to the invention, an interface CPRI1 of type CPRI is also used to connect two baseband processing entities BB1 and BB2 which are functionally identical. Thereby the corresponding subunits of the baseband processing units BB1, BB2 can communicate directly with each other. The following data types are sent:

Subscriber station data in the form of IQ data that must be transmitted to or received from subscriber stations,

Data in the form of control data received from the RNC and / or Operation and Maintenance Center (OMC), for example related to the operation and / or maintenance of subscriber station data form or baseband processing entities BB1 or BB2,

The control / maintenance data used for configuring the interface CPRI1 between the baseband processing entities BB1 and BB2 without being transmitted from the RNC or the OMC, for example which subscriber station data is used for the baseband processing entities BB1, Information as to whether exchanged between BB2), and

Synchronization data for synchronization between baseband processing entities BB1, BB2.

As a result, the same defined CPRI interface at the base station is functional on the other hand for the connection between functionally different baseband processing entities BB1 or BB2 and the transmit / receive units RE1 or RE2 on the other hand. For the connection between the same baseband processing entities BB1, BB2, it is used for two different types of connection. As a result, the same transmission methods in the physical layer and the same transmission protocols in the second layer are on the one hand between the baseband processing entities BB1 or BB2 and the transmit / receive units RE1 or RE2 and on the other hand. Available for communication between baseband processing entities BB1, BB2. Therefore, using the same transmission protocols used for subscriber station data between the baseband processing entities BB1 or BB2 and the transmit / receive units RE1 or RE2, the subscriber station data is converted to baseband processing entities. Can be transmitted between (BB1, BB2). According to the contents of the subscriber station data, the data received from the RNC and exchanged between the baseband processing entities BB1, BB2 is transmitted to or received from the subscriber station data or baseband processing entities BB1 or BB2. It may be transmitted using the same transmission protocols used for control data between (RE1 or RE2). Control and maintenance data that is not delivered from the RNC is baseband processed using the same transport protocol used for control data between the baseband processing entities BB1 or BB2 and the transmit / receive units RE1 or RE2. It may be transmitted between the entities BB1 and BB2. Finally, for synchronization data for synchronization between the baseband processing entities BB1 and BB2, synchronization data from baseband processing entities BB1 and BB2 may be sent to the transmission / reception units RE1 and RE2. It is possible to use the same transmission protocols used to transmit to the transmit / receive units RE1 or RE2 for synchronization.

Even if there are more baseband processing entities, the two baseband processing entities are connected together in each case via a CPRI interface, and all baseband processing entities except the two baseband processing entities are in each case two different Connected to baseband processing entities, and as a result, a continuous connection consisting of multiple connection pairs exists between all baseband processing entities. As a result, unlimited scalability of the base station's hardware is possible. Therefore, it is possible, for example, if it is desired to add an additional baseband processing entity connected via a CPRI interface to the most recently added baseband processing entity having only one connection to other baseband processing entities. Such scalability is not generally possible in the case of star-shaped connection structures, for example as shown in FIG. 2, and therefore the maximum number of baseband processing entities added is often in accordance with the prior art.

When the baseband processing entities BB1 or BB2 according to FIG. 1 are configured in each case of the modules CHC and KONZ according to FIG. 2, the connection of the baseband processing entities BB1 and BB2 according to FIG. 2 is independent. Due to the omission of the in-module KONZ, the number of modules required for each base station can be reduced. Since maintenance costs for base stations increase with the number of modules used, the use of the interface between functionally identical baseband processing entities results in a cost savings in operating the base stations.

By transmitting subscriber station data of the baseband processing entity BB1 to the baseband processing entity BB2 via the interface CPRI1 or vice versa, the interface between the baseband processing entities BB1, BB2 ( The use of CPRI1) allows the addition of subscriber station data in the frequency band prior to transmission. The baseband processing entity BB1 or BB2 which has performed the addition then passes the added subscriber station data via the interface CPRI2 to the transmit / receive unit RE1 or RE2 in charge of the relevant frequency.

With respect to the receiving direction, the connection of the two baseband processing entities BB1, BB2 via the interface CPRI1 provides different sectors each of the two transmit / receive units RE1, RE2 using the same radio frequency. It is especially preferable when. When both transmit / receive units RE1, RE2 receive subscriber station data of a subscriber station, the transmit / receive units RE1, RE2 interface to correspondingly connected baseband processing entities BB1, BB2. Pass the subscriber station data via (CPRI2). The subscriber station data is forwarded correspondingly to the other baseband processing entity BB1 or BB2 via the interface CPRI1 between the baseband processing entities BB1, BB2. Thereby, it is possible to combine the subscriber station data received over different sectors to raise the quality of the received subscriber station data.

The use of the interface CPRI1 is also useful for connecting the baseband processing entities BB1 and BB2 when the two baseband processing entities BB1 and BB2 belong to different network operators. For example, if the first network operator has authorization for the first frequency band and the second network operator has authorization for the second frequency band, then the two network operators are responsible for transmitting / receiving units RE1, RE2. Can be shared (site shared or antenna shared), and the first transmit / receive unit RE1 is used for both frequencies and the first sector, while the second transmit / receive unit RE2 has both frequencies. And for the second sector. The remaining entities on the network side in each case belong to only one of the network operators, each of the two network operators having baseband processing entities only for the authorized frequency. The baseband processing entity B1 of the first operator is connected to the first transmit / receive unit RE1 and the baseband processing entity B2 of the second operator is connected to the second transmit / receive unit RE2. The subscriber station data for the various subscriber stations, on which data is transmitted on the first or second frequency, is passed to the other baseband processing entity in each case using the interface CPRI1 before transmission, as a result of any frequency. Subscriber station data may be transmitted in different sectors in parallel or continuously. The same applies to the processing for subscriber station data of any frequency where data is received in different sectors.

The described multiple use of the same standard interface for connecting both functionally identical and functionally different modules is inexpensive and the device is implemented as the interface can be created in large unit volumes thereby reducing manufacturing costs. To be possible. In addition, the same software can be used for functionally identical and functionally different modules, thereby reducing the development costs of the software.

The described procedure can be similarly applied in more cases than the two baseband processing entities BB1, BB2. In this case, each baseband processing entity is in each case connected to one or two other baseband processing entities and to one or more transmit / receive units. It is also possible to intermesh baseband processing entities with each other, so that, for example, if there are three baseband processing entities, each baseband processing entity connects to both of the other baseband processing entities. do. In general, each baseband processing entity may be connected to any number of other baseband processing entities.

Claims (10)

An apparatus comprising at least one first unit (BB1, BB2), A first interface CPRI1 for transferring data between the first units BB1 and BB2 and second units BB1 and BB2 that are functionally identical to the first units BB1 and BB2; And And a second interface CPRI2 for transferring data between the first units BB1 and BB2 and the third units RE1 and RE2 that are functionally different from the first units BB1 and BB2. The first and second interfaces CPRI1 and CPRI2 may be A number of different data types may be transmitted in each case, and The first and second interfaces CPRI1 and CPRI2 are configured to be specified according to the same standard. Device. The method of claim 1, The standard provides for the transmission of different data types using a time division multiplexing method, Device. The method according to claim 1 or 2, The standard may provide an optical and / or electronic transmission method, Device. The method according to any one of claims 1 to 3, The standard provides Ethernet protocol and / or HDLC protocol as transport protocol, Device. The method according to any one of claims 1 to 4, The first unit BB1, BB2 and the second unit BB1, BB2 are in each case an entity for baseband processing radio signals. Device. The method according to any one of claims 1 to 5, The first units BB1 and BB2 are provided with means for processing data of the second units BB1 and BB2 that have been received via the first interface CPRI1. Device. The method according to any one of claims 1 to 6, The third unit RE1, RE2 is a transmitting and / or receiving entity for transmitting and / or receiving wireless signals, Device. The method according to any one of claims 1 to 7, The apparatus representing at least one component of a base station in a wireless communication system, Device. The method according to any one of claims 1 to 8, The first and second interfaces CPRI1 and CPRI2 indicate an interface specified according to a CPRI standard. Device. A method for operating an apparatus comprising at least one first unit BB1, BB2, Data is transmitted through the first interface CPRI1 between the first units BB1 and BB2 and the second units BB1 and BB2 that are functionally identical to the first units BB1 and BB2. Data is transmitted through the second interface CPRI2 between the first units BB1 and BB2 and the third units RE1 and RE2 that are functionally different from the first units BB1 and BB2. A number of different data types are in each case transmitted via the first and second interfaces CPRI1, CPRI2, and The first and second interfaces CPRI1 and CPRI2 are specified according to the same standard. Way.

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