JP2013183361A - Radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform baseband processing in cooperation among cells performing CA.SOLUTION: A radio base station eNB has a configuration in which: a layer 1 function unit can independently control each of cells #0 to #M under the radio base station eNB; and a layer 2 function unit and a scheduler function unit can control a plurality of cells (for example, cells #0 to #2) in groups #1 to #N performing CA, in a lump.

Description

  The present invention relates to a radio base station.

  In a LTE (Long Term Evolution) -Advanced mobile communication system whose specification is being promoted by 3GPP, it is considered to perform “CA (Carrier Aggregation)”.

  In the LTE-Advanced mobile communication system, the mobile station UE can perform CA with one radio base station eNB using a plurality of “Component Carriers (CC)” in different frequency bands at the same time. It is configured as follows.

  Also, when CA is performed, the mobile station UE sets one of a plurality of CCs as a PCC (Primary Component Carrer) and the other as an SCC (Secondary Component Carrer) according to an instruction from the radio base station. ) Is configured to set as.

  In the LTE-Advanced mobile communication system, it is considered to arrange one or a plurality of picocells in a high traffic area within the coverage area of a macrocell.

  For example, as shown in FIG. 6, when two pico cells # A / # B are installed in one macro cell, there is a possibility that CA using one macro cell and two pico cells # A / # B is performed. is there.

  Further, as shown in FIG. 6, when one pico cell is installed at the boundary between two macro cells # A / # B, CA using two macro cells # A / # B and one pico cell may be performed. There is.

JP 2011-142596 A

3GPP TS 36.814 3GPP TS 36.912

  For the following reasons, the applicant has discovered that when performing CA, it is necessary to perform baseband processing in cooperation between cells performing CA.

-Since ACK / NACK for a downlink signal is transmitted by a Pcell (serving cell in PCC), when a downlink signal is transmitted simultaneously between cells performing CA, it is necessary to control to avoid collision.

-In mobile station UE, there is a limit to the maximum data size (determined for each UE Category) that can be received in 1 TTI (Transmission Time Interval).

  However, as shown in FIG. 8, the existing LTE-Advanced radio base station eNB includes a baseband function unit that is independent for each cell. Here, each baseband function unit includes a layer 1 function unit, a layer 2 function unit, and a scheduler function unit.

  That is, there is a problem that the existing LTE-Advanced radio base station eNB cannot perform appropriate control when performing CA.

  Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to provide a radio base station that can perform baseband processing in cooperation between cells that perform CA.

  A first feature of the present invention is a radio base station, a layer 1 function unit configured to perform signal processing in layer 1 and a layer 2 configured to perform signal processing in layer 2 A functional unit and a scheduler functional unit configured to perform a scheduling process, and the layer 1 functional unit is provided so that each cell under the radio base station can be independently controlled. In summary, the layer 2 functional unit and the scheduler functional unit are provided so as to be able to collectively control a plurality of cells in a group performing CA.

  As described above, according to the present invention, it is possible to provide a radio base station that can perform baseband processing in cooperation between cells performing CA.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 3 is a functional block diagram of a radio base station according to the first embodiment of the present invention. FIG. 3 is a functional block diagram of a baseband functional unit in the radio base station according to the first embodiment of the present invention. It is a figure for demonstrating the mobile communication system which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the mobile communication system which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the conventional mobile communication system. It is a figure for demonstrating the conventional mobile communication system. It is a figure for demonstrating the conventional mobile communication system.

(Mobile communication system according to the first embodiment of the present invention)
A mobile communication system according to a first embodiment of the present invention will be described with reference to FIG. 1 to FIG. The mobile communication system according to the present embodiment is an LTE-Advanced mobile communication system.

  In the mobile communication system according to the present embodiment, the mobile stations UE # A1 to # B4 transmit / receive signals to / from the radio base station eNB using the CC of the frequency band F1 and the CC of the frequency band F2 at the same time. It is comprised so that CA can be performed, ie, it is comprised so that CA can be performed.

  As shown in FIG. 1, in the mobile communication system according to the present embodiment, a cell # A / # B1 / # B2 is provided as a macro cell under a radio base station eNB, and a cell # A1 / # is used as a pico cell. A2 / # B is provided.

  Here, the CC of the frequency band F1 is used in the macro cell of the cell # A / # B1 / # B2, and the CC of the frequency band F2 is used in the pico cell of the cell # A1 / # A2 / # B. .

  As shown in FIG. 1, for example, it is assumed that a core (coverage) band that emphasizes the area coverage range is used as the frequency band F1, and a capacity band that emphasizes high-speed communication is used as the frequency band F2. Yes.

  For example, an 800 MHz band, a 2 GHz band, or the like may be used as the frequency band F1, and a 3.5 GHz band or the like may be used as the frequency band F2.

  For example, the bandwidth of each CC may be either 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, or 20 MHz. In addition, 1.4MHz, 3MHz, 5MHz, 10MHz, or 20MHz is comprised by 6RB (Resource Block), 15RB, 25RB, 50RB, 75RB, or 100RB, respectively. 1 RB is 180 kHz.

  Further, the mobile communication system according to the present embodiment is configured such that the coverage area of cell #A and the coverage area of cell # A1 / # A2 are geographically overlapped, and the coverage area and cell of cell # B1 The coverage area of #B is configured to overlap geographically, and the coverage area of cell # B2 and the coverage area of cell #B are configured to overlap geographically.

  In the mobile communication system according to the present embodiment, the mobile stations UE # A1 to # B4 are configured such that the coverage area of the cell #A and the coverage area of the cell # A1 / # A2 overlap, the coverage area of the cell # B1 and the cell CA can be performed only in the area where the #B coverage area overlaps and the area where the cell # B2 coverage area and the cell #B coverage area overlap.

  As illustrated in FIG. 2, the radio base station eNB includes a radio communication unit 11 and a baseband function unit 12.

  The radio communication unit 11 is configured to perform processing related to radio communication with the mobile station UE. For example, the wireless communication unit 11 includes a transmission / reception antenna, a diplexer or a duplexer for suppressing interference, and the like.

  As shown in FIG. 3, the baseband function unit 12 includes a layer 1 function unit, a scheduler function unit, and a layer 2 function unit.

  The layer 1 functional unit is configured to perform signal processing in layer 1. For example, the layer 1 functional unit performs reception signal processing of uplink signals such as “Channel decoding”, “Channel de-mapping”, and “L1 measurement”, and downlink signals such as “Channel coding” and “Channel mapping”. It is configured to perform generation processing and the like.

  The scheduler function unit is configured to perform scheduling processing. For example, the scheduler function unit is configured to perform radio resource control such as MAC (Media Access Control) scheduling control.

  The layer 2 functional unit is configured to perform signal processing in layer 2. For example, the layer 2 function unit is configured to perform state management control of the mobile station UE, RLC (Radio Link Control) / PDCP (Packet Data Convergence Protocol) control, and the like.

  Here, as illustrated in FIG. 3, the layer 1 function unit is provided so that the cells # 0 to #M under the radio base station eNB can be controlled independently.

  In contrast, the layer 2 function unit and the scheduler function unit can collectively control a plurality of cells (for example, cells # 0 to # 2) in the groups # 1 to #N that perform CA. Is provided.

  Here, in the mobile communication system according to the present embodiment, as shown in FIG. 4, when cells # A / # A1 / # A2 / # B1 / # B2 / # B are arranged, cell #A and cell # There is a possibility that CA using A1 / # A2 may be performed, and CA using cell # B1 / # B2 and cell #B may be performed.

  Therefore, the radio base station eNB forms a group #A including cells # A / # A1 / # A2 and a group #B including cells # B / # B1 / # B2 as CA groups.

  In such a case, the radio base station eNB, as shown in FIG. 5, separate layer 1 function units A-1 / A-2 / for each cell # A / # A1 / # A2 / # B1 / # B2 / # B. A-3 / B-1 / B-2 / B-3.

  Here, each of the cells # A / # A1 / # A2 / # B1 / # B2 / # 3 is included in the layer 1 functional units A-1, A-2, A-3, B-1, B-2, and B-3. The signal processing in layer 1 in B is configured to be performed independently.

  Further, as shown in FIG. 5, the radio base station eNB includes a scheduler function unit A and a layer 2 function unit A for group #A, and a scheduler function unit B and a layer 2 function unit for group #B. B.

  Here, the layer 2 functional unit A and the scheduler functional unit A are configured to collectively control a plurality of cells # A / # A1 / # A2 in the group #A that performs CA.

  Similarly, the layer 2 functional unit B and the scheduler functional unit B are configured to collectively control a plurality of cells # B / # B1 / # B2 in the group #B that performs CA.

  For example, the scheduler function unit A determines whether to transmit a downlink signal to the mobile stations UE # A1 / # A2 / # A3 under the control of the cell # A / # A1 / # A2, or the cell #A / # A1 / # A2 subordinate mobile station UE # A1 / # A2 / # A3 whether to receive uplink signals, that is, cell # A / # A1 / # A2 subordinate mobile station UE # It is configured to determine whether to allocate resources to A1 / # A2 / # A3.

  In the example of FIG. 4, the scheduler function unit A is configured to perform resource allocation control for the mobile stations UE # A1 / # A2 / # A3 in the cell #A.

  In the example of FIG. 4, the scheduler function unit A is configured to perform resource allocation control for the mobile station UE # A1 in the cell # A1.

  Further, in the example of FIG. 4, the scheduler function unit A is configured to perform resource allocation control for the mobile station UE # A2 in the cell # A2.

  Here, the scheduler function unit A may be configured to perform resource allocation control in consideration of various restrictions in each mobile station UE and ACK / NACK collision with a downlink signal.

  For example, when the scheduler function unit A determines to transmit a downlink signal to the mobile station UE # A1 simultaneously in the cell #A and the cell # A1, the total data size to be transmitted is received by the mobile station UE # A1. When the maximum possible data size is exceeded, the data size transmitted in the cell #A or the cell # A1 may be reduced until it does not exceed the maximum data size receivable in the mobile station UE # A1. Good.

  Further, for example, the scheduler function unit A determines to transmit a downlink signal to the mobile station UE # A1 in the cell # A1, and downlinks to the mobile station UE # A2 in the cell # A2. When it is determined that signal transmission is performed, if transmission resources of ACK / NACK for the downlink signal are the same resource, transmission of the downlink signal in cell # A1 or cell # A2 is canceled. Alternatively, the ACK / NACK transmission resources for such downlink signals may be adjusted to be different resources.

  According to the mobile communication system according to the first embodiment of the present invention, the layer 2 function unit and the scheduler function unit in the radio base station eNB can collectively control a plurality of cells in a group performing CA. Therefore, baseband processing can be performed in cooperation between cells performing CA.

  The characteristics of the present embodiment described above may be expressed as follows.

  The first feature of this embodiment is a radio base station eNB, which is configured to perform signal processing in layer 2 and a layer 1 function unit configured to perform signal processing in layer 1 It comprises a layer 2 functional unit and a scheduler functional unit configured to perform scheduling processing, and the layer 1 functional unit can independently control each cell # 0 to #M under the radio base station eNB. The layer 2 functional unit and the scheduler functional unit can collectively control a plurality of cells (for example, cells # 0 to # 2) in the groups # 1 to #N that perform CA. The gist is that it is provided.

  In the first feature of this embodiment, the group described above may include one or more macro cells and one or more pico cells.

  The operations of the mobile station UE and the radio base station eNB described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both. .

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the mobile station UE or the radio base station eNB. Further, the storage medium and the processor may be provided as a discrete component in the mobile station UE or the radio base station eNB.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

UE ... mobile station eNB ... radio base station 11 ... radio communication unit 12 ... baseband function unit

Claims (2)

A wireless base station,
A layer 1 functional unit configured to perform signal processing in layer 1;
A layer 2 functional unit configured to perform signal processing in layer 2;
A scheduler function unit configured to perform a scheduling process,
The layer 1 functional unit is provided so that each cell under the radio base station can be controlled independently,
The radio base station, wherein the layer 2 function unit and the scheduler function unit are provided so as to collectively control a plurality of cells in a group performing CA (Carrier Aggregation).   The radio base station according to claim 1, wherein the group includes one or more macro cells and one or more pico cells.

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