WO2012005335A1 - Mobile communication method and wireless base station - Google Patents

Abstract

A mobile communication method comprises: a step in which a mobile station (UE) generates an "RA Preamble" on the basis of a RACH_ROOT_SEQUENCE for mobile stations (UE) contained in a received SIB, and transmits the "RA Preamble" to a wireless base station (DeNB); a step in which a relay node (RN) generates an "RA Preamble" on the basis of a RACH_ROOT_SEQUENCE for relay nodes (RN) contained in a received SIB, and transmits the "RA Preamble" to the wireless base statin (DeNB); and a step in which the wireless base station (DeNB) determines whether the transmission source of the received "RA Preamble" was the mobile station (UE) or the relay node (RN).

Description

Mobile communication method and radio base station

The present invention relates to a mobile communication method and a radio base station.

FIG. 11 shows a “contention based Random Access procedure” defined by 3GPP.

Specifically, as shown in FIG. 11, in Step 1, the mobile station UE transmits “Random Access (RA) Preamble” to the radio base station eNB. In Step 2, the radio base station eNB Then, “Random Access (RA) Response” is transmitted to the mobile station UE.

In step 3, the mobile station UE transmits “Schedule Transmission” to the radio base station eNB, and in step 4, the radio base station eNB transmits “Contention Resolution” to the mobile station UE.

3GPP TS36.300 10.1.5.1

In the LTE (Long Term Evolution) -Advanced scheme, the mobile station UE is configured to be able to connect to the radio base station DeNB via the relay node RN.

The relay node RN is also configured to execute the above-described RA procedure with the radio base station DeNB, similarly to the mobile station UE.

Further, when the relay node RN operates as “Half Duplex inband relay”, the relay node RN transmits a signal to the mobile station UE in a subframe other than the MBSFN (MBMS Single Frequency Network) subframe, and in the MBSFN subframe. The mobile station UE is configured not to transmit a signal.

Therefore, in this RA procedure, the radio base station DeNB needs to transmit “RA Response” in the MBSFN subframe to the relay node RN in order to avoid interference.

However, in the RA procedure described above, when the radio base station DeNB receives the “RA Preamble”, it cannot know whether or not the transmission source of the “RA Preamble” is the relay node RN. There has been a problem that “RA Response” cannot be transmitted to the node RN in the MBSFN subframe.

Therefore, the present invention has been made in view of the above-described problems, and provides a mobile communication method and a radio base station that allows the radio base station DeNB to grasp the transmission source of the received “RA Preamble”. With the goal.

A first feature of the present invention is a mobile communication method in which a radio base station transmits broadcast information including mobile station generation information and relay node generation information, and the mobile station receives the notification. A step of generating a random access preamble based on the mobile station generation information included in the information and transmitting the random access preamble to the radio base station; and the relay node generation included in the broadcast information received by the relay node Generating a random access preamble based on the information and transmitting the random access preamble to the radio base station; whether the radio base station is the source of the received random access preamble is a mobile station or a relay node And a step of determining the above.

A second feature of the present invention is a mobile communication method in which a radio base station transmits broadcast information indicating a relay node random access preamble range, and the relay node includes the relay node random access preamble range. Transmitting a random access preamble to the radio base station, and determining whether the radio base station is a mobile station or a relay node from which the random access preamble is received. It is summarized as having.

A third feature of the present invention is a radio base station, which is configured to transmit broadcast information including mobile station generation information and relay node generation information, and received random access And a determination unit configured to determine whether the preamble transmission source is a mobile station or a relay node.

The fourth feature of the present invention is a radio base station, which is configured to transmit broadcast information indicating a relay node random access preamble range, and to transmit the received random access preamble. The gist of the present invention is to include a determination unit configured to determine whether the source is a mobile station or a relay node.

As described above, according to the present invention, it is possible to provide a mobile communication method and a radio base station in which the radio base station DeNB can grasp the transmission source of the received “RA Preamble”.

FIG. 1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 2 is a functional block diagram of the radio base station according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a format of an information element “PRACH-Config” in the SIB transmitted by the radio base station according to the first embodiment of the present invention. FIG. 4 is a functional block diagram of the relay node according to the first embodiment of the present invention. FIG. 5 is a flowchart showing the operation of the mobile communication system according to the first embodiment of the present invention. FIG. 6 is a sequence diagram showing operations of the mobile communication system according to the first embodiment of the present invention. FIGS. 7A and 7B are diagrams for explaining the RN preamble assigned by the radio base station according to the second embodiment of the present invention. FIG. 8 is a diagram illustrating an example of a format of an information element “RACH-ConfigCommon” in the SIB transmitted by the radio base station according to the first embodiment of the present invention. FIG. 9 is a flowchart showing an operation of the mobile communication system according to the second embodiment of the present invention. FIG. 10 is a sequence diagram showing operations of the mobile communication system according to the second embodiment of the present invention. FIG. 11 is a diagram for explaining problems of a conventional mobile communication system.

(Mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 6, the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

As shown in FIG. 1, the mobile communication system according to the present embodiment is an LTE-Advanced mobile communication system, and includes a radio base station DeNB and a relay node RN.

Here, the radio base station DeNB and the relay node RN are connected by a Un interface, and the relay node RN and the mobile station UE are connected by an RN-Uu interface.

As shown in FIG. 2, the radio base station DeNB includes a broadcast information transmission unit 11, an RA procedure execution unit 12, and a determination unit 13.

The broadcast information transmitting unit 11 is configured to transmit MIB (Master Information Block) and SIB (System Information Block) as broadcast information to the subordinate cells.

Here, the broadcast information transmitting unit 11 is configured to transmit an SIB including RACH_ROOT_SEQUENCE for the mobile station UE and RACH_ROOT_SEQUENCE for the relay node RN.

For example, as illustrated in FIG. 3, the broadcast information transmission unit 11 sets RACH_ROOT_SEQUENCE for the mobile station UE in the information element “rootSequenceIndex” in the information element “PRACH-Config” in the SIB, and the information element “PRACH in the SIB The relay node RN RACH_ROOT_SEQUENCE is set in the information element “rootSequenceIndexRN” in “-Config”.

The RA procedure execution unit 12 is configured to perform an RA procedure between the mobile station UE and the relay node RN.

The determination unit 13 is configured to determine whether the transmission source of the “RA Preamble” received by the RA procedure execution unit 12 is the mobile station UE or the relay node RN.

Specifically, the determination unit 13 examines the RACH_ROOT_SEQUENCE used for generating the above-mentioned “RA Preamble” to determine whether the transmission source of the “RA Preamble” is the mobile station UE or the relay node RN. It may be configured to determine.

The determination unit 13 manages a table associating “RA Preamble” with RACH_ROOT_SEQUENCE. With reference to this table, whether the above-mentioned “RA Preamble” is transmitted from the mobile station UE or the relay node RN. It may be configured to determine whether there is.

Here, when the determination unit 13 determines that the transmission source of the above-mentioned “RA Preamble” is the relay node RN, the RA procedure execution unit 12 performs the relay node RN in the MBSFN subframe (backhaul subframe). Is configured to transmit "RA Response".

As shown in FIG. 4, the relay node RN includes a notification information receiving unit 21 and an RA procedure execution unit 22.

The broadcast information receiving unit 21 is configured to receive broadcast information transmitted by the radio base station DeNB.

The RA procedure execution unit 22 is configured to perform an RA procedure with the radio base station DeNB.

Here, the RA procedure execution unit 22 generates “RA Preamble” based on the RACH_ROOT_SEQUENCE for the relay node RN included in the SIB received by the broadcast information reception unit 21, and transmits it to the radio base station DeNB. It is configured.

Hereinafter, the operation of the mobile communication system according to the present embodiment will be described with reference to FIG. 5 and FIG.

Here, when the relay node RN operates as “Half Duplex inband relay”, the relay node RN transmits a signal to the mobile station UE in a subframe other than the MBSFN subframe, and in the MBSFN subframe, to the mobile station UE. It is assumed that no signal is transmitted.

In step S1001, the radio base station DeNB sets RACH_ROOT_SEQUENCE for the mobile station UE in the information element “rootSequenceIndex” in the information element “PRACH-Config”, and sets the information element “rootSequenceIndex” in the information element “PRACH-ConfigIndex”. SIB in which RACH_ROOT_SEQUENCE for node RN is set is transmitted.

In step S1002A, the relay node RN determines whether or not it is operating as “relay”, specifically, “Half Duplex inband relay”.

When it is determined that the relay node RN operates as “relay”, specifically, “Half Duplex inband relay”, in step S1002B, based on the RACH_ROOT_SEQUENCE for the relay node RN included in the SIB, “RA "Preamble" is generated.

On the other hand, if it is determined that the relay node RN is not operating as “relay”, that is, is operating as “UE”, in step S1002C, based on the RACH_ROOT_SEQUENCE for the mobile station UE included in the SIB, "Preamble" is generated.

In step S1002D, the relay node RN transmits the generated “RA Preamble” to the radio base station DeNB.

In step S1003A, the radio base station DeNB determines whether the transmission source of the received “RA Preamble” is the mobile station UE or the relay node RN.

When it is determined that the transmission source of the received “RA Preamble” is the relay node RN, the radio base station DeNB transmits “RA Response” to the relay node RN in the MBSFN subframe in Step S1003B.

On the other hand, when the radio base station DeNB determines that the transmission source of the received “RA Preamble” is the mobile station UE, in step S1003C, the radio base station DeNB performs “RA Response” to the mobile station UE in a normal subframe. Send.

In step S1004, the relay node RN transmits “Schedule Transmission” to the radio base station eNB, and in step S1005, the radio base station eNB transmits “Contention Resolution” to the relay node RN.

According to the mobile communication system according to the present embodiment, the radio base station eNB checks the RACH_ROOT_SEQUENCE used to generate the received “RA Preamble” so that the transmission source of the “RA Preamble” is the mobile station UE or the relay. It can be determined which of the nodes RN is.

(Mobile communication system according to the second embodiment of the present invention)
A mobile communication system according to the second embodiment of the present invention will be described with reference to FIG. 7 to FIG. Hereinafter, the mobile communication system according to the present embodiment will be described by focusing on differences from the mobile communication system according to the first embodiment described above.

In the conventional mobile communication system, as shown in FIG. 7A, 64 “RA Preambles” are divided by two parameters “numberOfRA-Preambles” and “numberOfRA-PreamblesGroupA”.

In the example of FIG. 7A, “RA Preamble # 0” to “RA Preamble # 60” are reserved as “RA Preamble” for contention, and “RA Preamble # 61” to “RA Preamble # 63”. Is secured as “RA Preamble” for non-contention.

In addition, among “RA Preamble” for contention, “RA Preamble # 0” to “RA Preamble # 47” are reserved as “RA Preamble” for transmission with small power, and “RA Preamble # 48” ˜ “RA Preamble # 60” is secured as “RA Preamble” for transmission with large power.

On the other hand, in the mobile communication system according to the present embodiment, as shown in FIG. 7B, the 64 “RA Preambles” include three parameters “numberOfRA-Preambles”, “numberOfRA-PreamblesRN”, and “ numberOfRA-PreamblesGroupA ".

In the example of FIG. 7B, “RA Preamble # 0” to “RA Preamble # 32” are reserved as “RA Preamble” for contention (“RA Preamble” for mobile station UE), and “RA Preamble # 32” “Preamble # 33” to “RA Preamble # 60” are reserved as “RA Preamble” for contention (“RA Preamble” for relay node RN), and “RA Preamble # 61” to “RA Preamble # 63” Is secured as “RA Preamble” for non-contention.

Here, “numberOfRA-PreamblesRN” is a parameter indicating the range “RA Preamble # 33” to “RA Preamble # 60” of “RA Preamble” for RN.

For example, as illustrated in FIG. 3, the broadcast information transmission unit 11 sets the range of “RA Preamble” for the UE in the information element “numberOfRA-Preambles” in the information element “RACH-ConfigCommon” in the SIB, and The range of “RA Preamble” for RN is set in the information element “numberOfRA-PreamblesRN” in the information element “RACH-ConfigCommon”.

The determination unit 13 is configured to determine whether the transmission source of the “RA Preamble” is the mobile station UE or the relay node RN based on the range to which the received “RA Preamble” belongs. .

Hereinafter, the operation of the mobile communication system according to the present embodiment will be described with reference to FIG. 9 and FIG.

Here, when the relay node RN operates as “Half Duplex inband relay”, the relay node RN transmits a signal to the mobile station UE in a subframe other than the MBSFN subframe, and in the MBSFN subframe, to the mobile station UE. It is assumed that no signal is transmitted.

In step S2001, the radio base station DeNB sets a range of “RA Preamble” for the UE in the information element “numberOfRA-Preambles” in the information element “RACH-ConfigCommon”, and information in the information element “RACH-ConfigCommon” An SIB in which the range of “RA Preamble” for RN is set in the element “numberOfRA-PreamblesRN” is transmitted.

In step S2002A, the relay node RN determines whether or not it is operating as “relay”, specifically, “Half Duplex inband relay”.

When it is determined that the relay node RN is operating as “relay”, specifically, “Half Duplex inband relay”, in step S2002B, the relay node RN is within the range of “RA Preamble” for the RN included in the SIB. “RA Preamble” is generated.

On the other hand, when it is determined that the relay node RN is not operating as “relay”, that is, is operating as “UE”, in step S2002C, the “RA Preamble” for the UE included in the SIB included in the SIB. “RA Preamble” within the range of is generated.

In step S2002D, the relay node RN transmits the generated “RA Preamble” to the radio base station DeNB.

In step S2003A, the radio base station DeNB determines whether the transmission source of the received “RA Preamble” is the mobile station UE or the relay node RN.

When it is determined that the transmission source of the received “RA Preamble” is the relay node RN, the radio base station DeNB transmits “RA Response” to the relay node RN in the MBSFN subframe.

On the other hand, when it is determined that the transmission source of the received “RA Preamble” is the mobile station UE, the radio base station DeNB transmits “RA Response” to the mobile station UE in a normal subframe.

In step S2004, the relay node RN transmits “Schedule Transmission” to the radio base station eNB, and in step S2005, the radio base station eNB transmits “Contention Resolution” to the relay node RN.

According to the mobile communication system according to the present embodiment, the radio base station eNB checks the range to which the received “RA Preamble” belongs, so that the source of the “RA Preamble” is either the mobile station UE or the relay node RN. Can be determined.

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

The first feature of the present embodiment is a mobile communication method, in which the radio base station DeNB includes RACH_ROOT_SEQUENCE for mobile station UE (generation information for mobile station) and RACH_ROOT_SEQUENCE for relay node RN (generation information for relay node). The step of transmitting SIB (broadcast information), and the mobile station UE generates “RA Preamble (random access preamble)” based on the RACH_ROOT_SEQUENCE for the mobile station UE included in the received SIB, to the radio base station DeNB And the step of the relay node RN generating “RA Preamble” based on the RACH_ROOT_SEQUENCE for the relay node RN included in the received SIB and transmitting it to the radio base station DeNB, the radio base station De B is the sender of the received "RA Preamble" is summarized in that and a step of determining for whether it is a mobile station UE or the relay node EN.

A second feature of the present embodiment is a mobile communication method in which the radio base station DeNB transmits an SIB indicating a range of “RA Preamble” for RN (random access preamble range for relay node); The relay node RN transmits the “RA Preamble” within the range of “RA Preamble” for the RN to the radio base station DeNB, and the source of the “RA Preamble” received by the radio base station DeNB And a step of determining whether the mobile station UE or the relay node RN.

In the first and second features of the present embodiment, the relay node RN transmits a signal to the mobile station UE in a subframe other than the MBSFN subframe, and the “RA” received by the radio base station DeNB When it is determined that the transmission source of “Preamble” is the relay node RN, a step of transmitting “RA Response (random access response)” to the relay node RN in the MBSFN subframe may be included.

A third feature of the present embodiment is a radio base station DeNB, which is received by a broadcast information transmitter 11 configured to transmit an SIB including RACH_ROOT_SEQUENCE for the mobile station UE and RACH_ROOT_SEQUENCE for the relay node RN. The gist of the present invention is to include a determination unit 13 configured to determine whether the transmission source of “RA Preamble” is the mobile station UE or the relay node RN.

The fourth feature of the present embodiment is a radio base station DeNB, which is configured to transmit an SIB indicating the range of “RA Preamble” for RN, and the received “RA The gist of the invention is that it includes a determination unit 13 configured to determine whether the transmission source of “Preamble” is the mobile station UE or the relay node RN.

In the third and fourth characteristics of the present embodiment, when the determination unit 13 determines that the transmission source of “RA Preamble” is the relay node RN, in the MBSFN subframe, “ RA procedure execution unit 12 (random access procedure execution unit) configured to transmit “RA Response” is provided, and in the MBSFN subframe, a signal addressed to mobile station UE is transmitted by relay node RN. It does not have to be.

The operations of the radio base station DeNB, the relay node RN, and the mobile station UE described above may be performed by hardware, may be performed by a software module executed by a processor, or may be performed by a combination of both. May be.

The software modules include RAM (Random Access Memory), flash memory, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electronically Erasable and Programmable, Removable ROM, Hard Disk, and Removable ROM). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

The 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 radio base station DeNB, the relay node RN, or the mobile station UE. Further, the storage medium and the processor may be provided in the radio base station DeNB, the relay node RN, and the mobile station UE as discrete components.

As described above, the present invention has been described in detail using the above-described embodiments. However, it is obvious for those skilled in the art that the present invention is not limited to the embodiments described in the present specification. The present invention can be implemented as modifications and changes 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 DeNB ... radio base station RN ... relay node 11 ... notification information transmission unit 12, 22 ... RA procedure execution unit 13 ... determination unit 21 ... notification information reception unit

Claims (6)

A step in which a radio base station transmits broadcast information including generation information for mobile stations and generation information for relay nodes;
A mobile station generates a random access preamble based on the mobile station generation information included in the received broadcast information and transmits the random access preamble to the radio base station;
A relay node generates a random access preamble based on the relay node generation information included in the received broadcast information, and transmits the random access preamble to the radio base station;
And a step of determining whether the wireless base station is a source of the received random access preamble is a mobile station or a relay node. A radio base station transmitting broadcast information indicating a relay node random access preamble range;
A relay node transmitting a random access preamble within the relay node random access preamble range to the radio base station;
And a step of determining whether the wireless base station is a source of the received random access preamble is a mobile station or a relay node. The relay node transmitting a signal to the mobile station in a subframe other than an MBSFN subframe;
And a step of transmitting a random access response to the relay node in the MBSFN subframe when the radio base station determines that the transmission source of the received random access preamble is a relay node. The mobile communication method according to claim 1 or 2. A broadcast information transmitter configured to transmit broadcast information including mobile station generation information and relay node generation information;
A radio base station comprising: a determination unit configured to determine whether a transmission source of a received random access preamble is a mobile station or a relay node. A broadcast information transmitter configured to transmit broadcast information indicating a relay node random access preamble range;
A radio base station comprising: a determination unit configured to determine whether a transmission source of the received random access preamble is a mobile station or a relay node. When the determination unit determines that the transmission source of the random access preamble is a relay node, the random access procedure is configured to transmit a random access response to the relay node in an MBSFN subframe. An execution unit,
The radio base station according to claim 4 or 5, wherein in the MBSFN subframe, transmission of a signal addressed to a mobile station by the relay node is not performed.

Images