WO2011020212A1

WO2011020212A1 - Handover method and base station, relay node and communication system thereof

Info

Publication number: WO2011020212A1
Application number: PCT/CN2009/000940
Authority: WO
Inventors: 杨涛; 温萍萍; 刘瑾
Original assignee: 上海贝尔股份有限公司; 阿尔卡特朗讯
Priority date: 2009-08-17
Filing date: 2009-08-17
Publication date: 2011-02-24
Also published as: CN102474761A

Abstract

Disclosed is a handover method in a cell covered by a base station and arranged with one or more relay nodes, the method includes: configuring the one or more relay nodes to detect the time of random access signal PRACH transmission; requesting a user equipment located in an edge area of the cell to perform PRACH transmission; the one or more relay nodes detecting the information related to the PRACH transmission from the user equipment, and sending a detection report to the base station; based on the sent detection report of the one or more relay nodes, the base station selecting an appropriate relay node to serve the user equipment, and sending a notification to the user equipment. Disclosed are also the corresponding base station, relay node and communication system.

Description

Switching method and corresponding base station, relay node and communication system

Embodiments of the present invention relate to a handover method in a cell in which a relay node is deployed, and a corresponding base station, a relay node, and a communication system, and specifically, to a cell in which a relay node is not involved, and in a cell in which a relay node is deployed Switching method and corresponding base station, relay node and communication system. Background technique

A type II relay node RN (Relay Node) is defined in 3GPP with the following features:

• Type Π Relay Node RN should not have a separate cell ID, so no new cell will be created, and the eNB has no interference problems and can work together on the UE;

• Type II relay node RN should be able to relay to version 8 user equipment (Rel-8 UE) or from Rel-8

UE relay

• At least the Rel-8 UE should not be aware of the existence of the Type II Relay Node RN.

3GPP standardizes the type II relay node RN implementation framework:

• The RN transmits and receives in the same UL or DL band of the eNB by time division multiplexing TDM mode; • For the relay-assisted Rel-8 UE in the eNB PDCCH (Control Channel) coverage area, only the Release 8 PDCCH should be received from the eNB. /CRS; and can receive PDSCH (Physical Downlink Shared Channel) transmission transmitted by the RN; • The application of the Type II relay node RN to extend the eNB cell is for further study.

See, for example, 3GPP TR 36. 814 0. 4. 1 (February 2009), which is hereby incorporated by reference. According to the above definition, for the type of throughput improvement scenario, the relay node RN will not transmit the pilot channel. This means that the UE can only measure the downlink pilot channel of the eNB. In addition, since the Type II relay node RN does not have its own cell ID, there should be no handover H0 (Handover) procedure when the UE moves within the coverage area of the eNB. But in fact, from the perspective of the UE, there are four possible locations, as shown in Figure 1: Position 1: The UE is only in the coverage area of the eNB;

Position 2: The UE is still in the coverage area of the eNB, but is moving into the coverage area of the RN; • Location 3: The UE moves from one RN to the coverage area of another RN belonging to the same eNB;

• Location 4: The UE is outside the coverage area of the eNB and is moving into the coverage area of another eNB.

Accordingly, there are three possible switching scenarios:

, scenario 1: from location 1 to location 2, where the UE moves from the coverage area of the eNB to the coverage area of the RN; • Scenario 2: From location 2 to location 3, where the UE moves from the coverage area of one RN to the coverage area of another RN;

• Scenario 3: From location 2 to location 4, where the UE moves into the coverage area of another eNB.

For scenario 3, a traditional inter-site handover process can be used, so this scenario is no longer discussed. For scenarios 1 and 2, the appropriate node should be determined to serve the UE, and the UE must be up-synchronized with the node. In order to support backward compatibility, all of these processes must be performed without the UE participating. Here, since there is no influence on the UE, these processes are called "virtual switching".

Type II relay node RN is not introduced in the existing Long Term Evolution LTE system, so the type is deployed.

II Relay Node The cell of the RN cannot use the existing handover procedure defined in LTE. So far, there is no corresponding solution. Summary of the invention

The object of the present invention is to propose a virtual handover scheme in a cell in which a Type II relay node RN is deployed, in which the UE does not participate.

According to an aspect of the present invention, a handover method in a cell covered by a base station in which one or more relay nodes are deployed is provided, including: configuring random access for the one or more relay nodes Information about channel PRACH signal transmission; requesting user equipment located at a cell edge location to perform PRACH transmission; the one or more relay nodes detecting related information of PRACH transmission from the user equipment, and transmitting a detection report to the base station; The detection report of one or more relay nodes, the base station selects a suitable relay node to serve the user equipment, and sends a notification to the user equipment.

The method further includes: estimating whether the user equipment is located at a cell edge, wherein the user equipment is estimated to be located at a cell edge when the downlink measurement report sent by the user equipment to the base station or the uplink reception quality of the base station is below a predetermined threshold.

When it is possible to receive a report from the relay node indicating that the uplink UL reception quality of the relay node is below a predetermined threshold, it is estimated that the user equipment moves out of the coverage area of the relay node. Alternatively, when the received uplink UL reception quality from the relay node is below a predetermined threshold, it is estimated that the user equipment moves out of the coverage area of the relay node. The method also includes: requesting the relay node to perform a release process.

The notification sent to the user equipment includes: a TA command including the timing advance TA information related to the selected relay node calculated by the base station according to the report of the selected relay node.

The method also includes: configuring the selected relay node to serve the user equipment. The one or more relay nodes may be type π relay nodes.

According to another aspect of the present invention, a base station capable of performing handover in a cell covered by a base station in which one or more relay nodes are deployed is provided, including: configuration means for configuring the one or more Information about the random access channel PRACH signal transmission required by the node; the requesting device, configured to request the user equipment located at the cell edge location to perform PRACH transmission; and the receiving device, configured to receive the one or more relay nodes to send a detection report on related information of PRACH transmission of the user equipment, wherein the one or more relay nodes detect related information of PRACH transmission from the user equipment; and selecting means, selecting an appropriate relay node service based on the detection report And a sending device, sending a notification to the user equipment.

The base station further includes: an estimating device, configured to estimate whether the user equipment is located at a cell edge, where when the downlink measurement report sent by the user equipment to the base station or the uplink reception quality of the base station is lower than a predetermined threshold, The estimating device estimates that the user equipment is located at the edge of the cell.

The estimating device estimates, according to the report from the relay node, that the user equipment moves out of the coverage area of the relay node, and the report indicates that the uplink UL reception quality of the relay node is lower than a predetermined threshold. Alternatively, the estimating means estimates that the user equipment moves out of the coverage area of the relay node when the received uplink UL reception quality from the relay node is lower than a predetermined threshold. The requesting device is further configured to request the relay node to perform a release process.

The base station further includes: computing means for calculating a timing advance TA information associated with the selected relay node based on the report of the selected relay node.

The notification includes: a TA command including the timing advance TA information.

The one or more relay nodes may be Type II relay nodes.

According to an aspect of the present invention, a relay node capable of performing handover in a cell in which one or more relay nodes are deployed is provided, comprising: receiving means for receiving a random access channel PRACH signal from a user equipment a transmitting device, configured to detect information about a random access channel PRACH signal transmission and related information of a PRACH transmission from a user equipment, and a sending device, configured to send, to the base station, about the user equipment A test report for the relevant information of the PRACH transmission.

The sending device is further configured to send a report to the base station, where the report indicates that the UL receiving quality of the relay node is lower than a predetermined threshold. Alternatively, the sending device is further configured to send, to the base station, a UL reception quality of the relay node.

According to another aspect of the present invention, a communication system capable of performing handover in a cell in which one or more relay nodes are deployed is provided, including a base station, one or more relay nodes, and user equipment as described above . According to the solution of the embodiment of the present invention, almost all tasks are performed at the eNB and the relay node. All the UE needs to do is perform a dedicated or contention-based PRACH transmission and use the new TA command when it receives a new TA command. All of these are normal operations of the UE, and the UE does not know that these procedures are performed for the purpose of virtual handover, and thus there is no new Radio Resource Connection (RRC) setup procedure. From this perspective, the UE does not participate in virtual switching and thus supports backward compatibility. DRAWINGS

The above and other aspects, features, and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the invention. Possible locations of the UE in the communication environment;

2 is a block diagram showing the structure of an LTE system according to an embodiment of the present invention;

3 is a message flow diagram showing a virtual handover procedure for scenario 1 in an LTE system according to an embodiment of the present invention;

4 is a message flow diagram showing a virtual handover procedure for scenario 2 in an LTE system in accordance with one embodiment of the present invention. detailed description

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In this exemplary embodiment, an LTE system is taken as an example. In the LTE system, multiple Type II relay nodes RN are deployed in a cell covered by the eNB. However, those skilled in the art should understand that the scope of the present invention is not limited thereto, and the specific embodiment is only for the purpose of description, and should be regarded as an example of the invention, The switching process performed by the scenes falls within the scope of the present invention.

Since it is defined in 3GPP: In the coverage area of the Type II relay node RN operating in the scenario of improving throughput, only the eNB transmits the lower pilot channel. Thus, in order to solve the first problem of the embodiment of the present invention, the following two possible options are designed:

* Option 1: Based on the DL measurements reported by the UE to the eNB, consider the following:

Mode 1: The reported value is within a predetermined threshold within a predetermined time, and the UE is only in the coverage area of the eNB (position 1 in FIG. 1)

Mode 2: The reported value is lower than a predetermined threshold, and the UE may be located in the coverage area of both the eNB and the RN (position 2 or 3 in FIG. 1), but in this case, the eNB does not know which RN the UE is located in. Covered area. * Option 2: Based on the UE UL transmission quality received by the eNB, for example, a physical uplink control channel PUCCH signal, an uplink shared channel PUSCH signal, a channel sounding reference signal SRS, etc., the following manner may be adopted:

Mode 1: If the UL reception quality is higher than a predetermined threshold within a predetermined time, the UE is only in the coverage area of the eNB (position 1 in FIG. 1);

Mode 2: Otherwise, if the UL reception quality is lower than the predetermined threshold, the UE may be located in the coverage area of both the eNB and the RN (position 2 or 3 in Fig. 1).

Based on the above, the location of the UE can be divided into the following cases -

• Case 1: The UE is in the coverage area of the eNB (position 1 in Figure 1);

• Case 2: The UE is located in the coverage area of both the eNB and the RN (positions 2 and 3 in Figure 1). But in this case, the UE may be located at the cell edge of the eNB;

• Case 3: The UE moves to the coverage area of another eNB (Location 4 in Figure 1).

After determining the location of the UE, the second problem is to select the appropriate relay node to serve the UE and implicitly establish UL synchronization with the selected relay node.

For case 1, the eNB should be used to directly serve the UE, and no specific action is required. For Case 3, a traditional inter-site handover procedure should be employed, with the difference that the target eNB should determine whether to use its relay node to serve the UE. However, embodiments of the present invention are only directed to Case 2, which does not involve a UE (referred to as "virtual handoff") during handover.

For Case 2, there are two types of Virtual Switching (VH0) scenarios:

VH0 scenario 1: In a cell covered by an eNB in which a type Π relay node RN is deployed, the UE moves from the coverage area of the eNB to the coverage area of the RN;

H0 scenario 2: Move from the coverage area of one RN in the area covered by the eNB to the coverage area of another RN.

For these two scenarios, from the perspective of the network, the eNB should select the appropriate Type II relay node to serve the UE. From the perspective of the UE, the UE must synchronize with the selected relay node UL to ensure its UL transmission. To this end, the following communication systems and methods have been designed.

The structure of an LTE communication system according to an embodiment of the present invention will be described below with reference to FIG. FIG. 2 schematically illustrates an LTE communication system 200 including a UE 201, an eNB 202, and an RN 203. It should be noted that one or more relay nodes deployed in the system have the same structure. To avoid confusion, only the schematic system structure with one relay node RN 203 is shown in FIG. It should also be noted that this schematic FIG. 2 omits the conventional structure or configuration so as not to obscure the understanding of the present invention. The dotted arrows in Figure 2 indicate the individual settings. Radio communication between backups.

In an embodiment of the present invention, the base station eNB 202 includes: a first receiving device 2021 and a first transmitting device 2022 that perform mutual transmission with the UE 201; and a second receiving device 2023 and a second transmitting device 2024 that perform mutual transmission with the RN 203. And a configuration device 2025, an estimation device 2026, a request device 2027, a selection device 2028, and a computing device 2029. It should be understood that although two sets of receiving/transmitting means are provided for communication with the UE 201 and the RN 203, respectively, in this embodiment, in an alternative embodiment of the present invention, the eNB 202 may also employ a set of receiving. The transmitting device implements communication with the UE 201 and the RN 203. The relay node RN 203 includes: a receiving device 2031, a transmitting device 2032, and a detecting device 2033.

Since in this embodiment one or more RNs 203 are deployed within the cell covered by the eNB 202, the configuration device 2025 in the eNB 202 will first be required for one or more RNs 203 within the cell covered by the eNB 202. The information about the random access channel PRACH signal transmission is configured, for example, at least information about the time and resources of the RN regarding the PRACH transmission. The eNB 202 sends the configuration information to the RN 203 via the second transmitting device 2023.

The eNB 202 utilizes the estimating means 2026 to estimate the location of the UE 201 based on the downlink DL measurement report (or alternatively, the uplink UL reception quality) received by the first receiving device 2021 from the UE 201.

For example, when the reported DL measurement (or alternatively, the UL reception quality) is below a predetermined threshold within a predetermined time, the estimating means 2026 estimates that the UE 201 is located at the cell edge. At this point, one or more relay nodes RN 203 deployed in the cell may be employed to enhance the throughput of the cell edge. It should be noted that at this time, the eNB 202 cannot determine in which coverage area the RN 203 the UE 201 is located.

Next, the eNB 202 request 2027 requests 201 through the first transmitting device 2022 to perform a dedicated or contention-based PRACH transmission. Then, in response to the transmission request, the UE 201 performs a PRACH transmission according to the request of the requesting device 2027 in the eNB 202.

After the one or more RNs 203 in the system 200 receive the PRACH transmission from the UE 201 through the receiving device 2031, the PRACH transmission from the UE 201 is detected by the detecting device 2033, and reported to the eNB 202 by the transmitting device 2032 of the RN 203. The report may include RACH preamble information, quality and time information such as received power, and the like.

The eNB 202 receives the PRACH detection report from the transmitting device 2032 of the RN 203 using the second receiving device 2024, and selects the appropriate RN 203 to serve the UE 201 based on the received detection report by the selecting device 2028. Then, through the computing device 2029, the timing advance TA information related to the selected relay node is calculated according to the report of the selected relay node, and the notification is sent to the UE 201 by the first sending device 2022, the notification includes: The time advances the TA command of the TA information so that the UE 201 can communicate synchronously with the selected relay node RN 203.

At the same time, the eNB 202 transmits, to the receiving device 2031 of the selected relay node RN 203, the configuration information of the relay node RN 203 selected by the selecting device 2028 by the second transmitting device 2023 to configure the selected relay node RN 203, To serve user equipment.

Finally, the UE 201 performs UL synchronous transmission with the selected relay node RN 203 based on the TA information in the received notification.

If the estimating means 2026 is capable of receiving the UL reception quality from the transmitting means 2032 in the RN 203, the UL reception quality is compared with a predetermined threshold. If the UL reception quality is lower than the predetermined threshold within a predetermined time, it is estimated that the UE 201 moves out of the coverage area of the RN 203, that is, scenario 2.

Optionally, the RN 203 may include a comparing device (not shown) for comparing the UL reception quality of the RN 203 with a predetermined threshold, and when the UL reception quality of the RN 203 is lower than a predetermined threshold within a predetermined time. And transmitting, by the transmitting device 2032, a report indicating that the UL reception quality of the RN 203 is lower than a predetermined threshold within a predetermined time. In the alternative embodiment, the estimating means 2026 can estimate that the UE 201 has moved out of the coverage area of the RN 203 based on the report from the transmitting device 2032 of the RN 203.

Next, the eNB 202 also requests the UE 201 to perform a dedicated or contention-based PRACH transmission through the requesting device 2027. Then, in response to the transmission request, the UE 201 performs PRACH transmission in accordance with a request from the requesting device 2027 in the eNB 202.

The eNB 202 receives the PRACH detection report from the transmitting device 2032 of the RN 203 using the second receiving device 2024, and selects the appropriate RN 203 to serve the UE 201 based on the received detection report by the selecting device 2028. Then, through the computing device 2029, the timing advance TA information related to the selected relay node is calculated according to the report of the selected relay node, and the notification is sent to the UE 201 by the first sending device 2022, the notification includes: including the time The TA command of the TA information is advanced in advance so that the UE 401 can communicate synchronously with the selected relay node RN 403.

At the same time, the eNB 202 transmits the configuration information of the relay node RN 203 selected by the configuration device 2025 to the selection device 2028 to the receiving device 2031 of the selected relay node RN 203 through the second transmitting device 2023, so as to The relay node RN 203 is configured to serve the user equipment.

In the case where it is determined that the UE 201 has moved out of the coverage area of the RN 203 (Scenario 2), the eNB 202 may also remove the coverage by the requesting device 2027 after selecting the suitable relay node RN 203 by the selecting means 2028. The RN of the area requests to release the communication connection with the UE 201.

For a UE in a cell in which a relay node is deployed, a scheme according to an embodiment of the present invention can determine a node serving the UE and can select an optimal relay node to serve the UE.

Although the transmitting device, the relay device, and the receiving device of the embodiments of the present invention have been described above in the form of separate functional modules, each of the components shown in FIG. 2 can be implemented by a plurality of devices in practical applications, as shown. Multiple components can also be integrated into a single chip or a device in practical applications.

The virtual switching process performed in the above two scenarios will be described below with reference to FIG. 3 and FIG. 4 respectively. FIG. 3 is a message flow diagram showing a virtual switching process for scenario 1 in the LTE communication system 200 in accordance with an embodiment of the present invention.

Since in this embodiment, one or more RNs are deployed in the cell covered by the eNB 202, the eNB 202 first uses the configuration device 2025 to utilize one or more RNs in the cell covered by the configuration device 2025. The required information about the PRACH transmission is configured, for example, at least information about the time and resources of the RN regarding the PRACH transmission. The eNB 202 configures the RN 203 to detect the transmission opportunity of each PRACH.

In the scenario of this embodiment, only the eNB 202 transmits the lower pilot channel, and the UE 201 measures the pilot channel of the eNB 202.

In step S303, the eNB 202 may estimate the location of the UE according to the DL measurement report from the UE by the estimating means 2026.

Specifically, if the reported DL measurement is within a predetermined threshold within a predetermined time, the UE is only within the coverage area of the eNB 202 (position 1 in FIG. 1); otherwise, if the reported time is within the predetermined time When the DL measurement is below a predetermined threshold, the eNB 202 estimates that the UE is located at the cell edge (position 2 or 3 in Figure 1).

In an alternative embodiment, eNB 202 may also estimate the location of UE 201 based on UL reception quality (e.g., PUCCH, PUSH, SRS, etc.).

Specifically, in the optional embodiment, if the UL reception quality is higher than a predetermined threshold within a predetermined time, the UE is only in the coverage area of the eNB 202 (position 1 in FIG. 1); otherwise, if the UL reception quality is Below a predetermined threshold, the eNB 202 estimates that the UE is located at the cell edge (position 2 or 3 in Figure 1). In step S305, when the reported DL measurement (or optionally, UL reception quality) is below a predetermined threshold, the eNB 202 estimates that the UE is located at the cell edge. At this time, the type II relay node RN deployed in the cell can be used to enhance the throughput of the cell edge. At this time, the eNB 202 cannot determine which RN is in the coverage area of the RN.

In step S307, the eNB 202 requests the UE to perform a dedicated or contention-based PRACH transmission through the requesting device 2027. Then, in step S309, the UE performs PRACH transmission according to the request of the eNB 202.

In step S311, one or more relay nodes RN (RN1 and RN2 in this embodiment) deployed in the cell covered by the eNB 202 attempt to detect the PRACH transmission by using the detecting means 2033, and correspondingly to the eNB 202 report. The report may include RACH preamble information, quality information such as received power, time information, and the like.

In step S313, based on the report of each relay node, the eNB 202 selects the best relay node (hereinafter referred to as "service relay node") from the selection device 2028 to serve the UE, and calculates by the computing device 2029. Related time advance (TA) information.

In step S315, the eNB 202 also configures the service relay node by the configuration device 2025, such as establishing a related layer 2 (L2) function, configuring a related radio bearer, and the like. The service relay node that received the configuration information performs configuration and is ready to serve the UE 201.

In step S317, the eNB 202 transmits, via the first transmitting device 2022, the TA command including the latest calculated TA information related to the selected serving relay node to the UE on the downlink.

It should be noted that steps S315 and S317 in this embodiment are not meant to limit the order of the two steps. In an alternative embodiment, step S317 may be performed first, then step S315 may be performed, or both may be performed simultaneously. .

In step S319, the UE performs subsequent UL transmissions according to the received TA command. By receiving the TA information associated with the selected serving relay node, the UE' is able to synchronize the UL transmission with the selected serving relay node.

As can be seen from the above description of FIG. 3, the eNB 202 can only estimate whether the UE 201 is located at the cell edge based on the DL measurement report or UL reception quality of the UE 201, and further according to the PRACH detection report of each relay node deployed in the cell. The coverage area of which relay node the UE is in is determined and served by it. However, the eNB 202 cannot know whether the UE 201 has crossed the coverage area of the relay node.

In order to solve this problem, the embodiment of the present invention proposes that a relay node (ie, a serving relay node) currently serving the UE should report its UL reception quality to the eNB, for example, PUCCH, PUSCH or SRS. If the UL reception quality from the serving relay node is below a predetermined threshold, the eNB estimates that the UE may be moving out of the coverage area of the serving relay node (ie, scenario 2), thus triggering the virtual handover again. This process will be combined with Figure 4. It is described below.

4 is a message flow diagram showing a virtual switching process for scenario 2 in an LTE communication system 200 in accordance with an embodiment of the present invention. In scenario 2, UE 201 moves from the coverage area of one Type II relay node 203 RN1 within the cell covered by eNB 202 to the coverage area of another Type II relay node 203 RN2.

First, in the same scenario as in scenario 1, in step S401, the eNB 202 configures the information about the PRACH transmission required by one or more RNs in the cell it covers by the configuration device 2025, for example, at least for the RN. Information about the time and resources of the PRACH transmission is configured. The eNB 202 configures the RN 203 to detect the transmission opportunity of each PRACH. . In the scenario of this embodiment, only the eNB 202 transmits the lower pilot channel, and the UE 201 measures the pilot channel of the eNB 202. In step S403, the eNB 202 may estimate the location of the UE by using the estimating device 2026 according to the DL measurement report from the UE, or the UL reception quality (e.g., PUCCH, PUSH, SRS, etc.) received by the first receiving device 2021.

Different from scenario 1, in scenario 2, since there is a serving relay node serving the UE (referred to as a "source relay node"), it is necessary to report the UL reception quality of the source relay node to the eNB 202. .

Thus, in step S404, the source relay node 203 RN1 measures its UL reception quality and reports to the eNB 202 when a predetermined rule is satisfied (e.g., the UL reception quality is below a predetermined threshold within a predetermined time). In an alternative embodiment, the UL reception quality of the source relay node may also be sent directly to the eNB 202 in step 404, and then compared to a predetermined threshold at the eNB 202.

That is, the comparison of the source relay node UL reception quality with a predetermined threshold may be performed at the source relay node or at the eNB 202 thereafter.

In step S405, when the DL measurement report from the UE 201 (or optionally, the UL reception quality of the eNB 202) is lower than a predetermined threshold and received a source with respect to the M relay of the source relay node being below a predetermined threshold Following the reporting of the node (or alternatively, when the UL reception quality of the source relay node sent to the eNB 202 is below a predetermined threshold), the eNB 202 learns that the UE is moving out of the coverage area of the source relay node.

In step S407, the eNB 202 triggers the virtual handover procedure by requesting the UE 201 to perform a dedicated or competition-based PRACH transmission by using the requesting means 2027.

In step S409, the UE performs PRACH transmission accordingly according to the request of the eNB 202.

In step S411, one or more relay nodes RN (RN1 and RN2 in this embodiment) deployed in the cell covered by the eNB 202 perform PRACH reception by using the receiving device 2031, and attempt to detect the detection by the detecting means 2033. The PRACH transmits and reports to the eNB 202 including random access code information, received power, time information, and the like. In step S413, based on the report of each relay node, the eNB 202 selects a suitable relay node (referred to as a "target relay node") from the selection device 2028 to serve the UE, and uses the computing device 2029 to calculate the relevant TA information. In step S415, the eNB 202 performs corresponding configuration on the target relay node by the configuration device 2025, and requests the source relay node RN1 to perform the release process by the requesting device 2027 in step S416. The target relay node that received the configuration information performs configuration and is ready to serve the UE 201. It should be noted that steps S415 and S417 in this embodiment are not meant to limit the order of the two steps. In an optional embodiment, step S417 may be performed first, then step S415 may be performed, or both may be performed simultaneously. .

In step S417, the eNB 202 transmits, via the first transmitting device 2022, the TA command including the latest calculated TA information related to the selected serving relay node to the UE on the downlink.

In step S419, the UE performs subsequent UL transmissions accordingly according to the received new TA command. By receiving the TA information associated with the target relay node, the UE can synchronize the UL transmission with the target relay node, and the virtual handover process is completed.

Obviously, for the above two virtual handover scenarios, almost all tasks are performed by the eNB 202 and the relay node. All the UE needs to do is to perform dedicated or contention-based PRACH transmission, and use the new TA command when receiving a new TA command, all of which are normal operations of the UE, and the UE does not know that these procedures are directed to Performed for the purpose of virtual switching. From this perspective, the UE does not participate in virtual switching and thus supports backward compatibility.

The above embodiments of the present invention are directed to a cell in which a Type II relay node RN is deployed, and cannot adopt the existing handover procedure defined in LTE, and provide a corresponding solution, which provides that the user equipment does not participate in the deployment. A "virtual" handover method in a cell of a relay node and a corresponding base station, relay node, and communication system. According to the solution of the present invention, almost all tasks are performed at the eNB and the relay node. All the UE needs to do is perform a dedicated or contention-based PMCH transmission and use the new TA command when it receives a new TA command. All of these are normal operations of the UE, and the UE does not know that these procedures are performed for the purpose of virtual handover, and thus there is no new radio resource control RRC connection establishment procedure. From this perspective, the UE does not participate in virtual switching and thus supports backward compatibility.

Those skilled in the art will readily recognize that the various steps of the above methods can be implemented by a programmed computer. Herein, some embodiments also include a machine readable or computer readable program storage device (eg, a digital data storage medium) and encoding machine executable or computer executable program instructions, wherein the instructions perform some of the above methods or All steps. For example, the program storage device can be a digital memory, a magnetic storage medium (such as a magnetic disk and magnetic tape), hardware, or an optically readable digital data storage medium. Embodiments also include a method of performing the above method The programming computer that describes the steps.

The description and drawings merely illustrate the principles of the invention. It will be appreciated that those skilled in the art are able to devise various structures, and the various structures are not described or illustrated herein, but are intended to be within the spirit and scope. In addition, all of the examples mentioned herein are explicitly used primarily for teaching purposes to assist the reader in understanding the principles of the present invention and the ideas contributed by the inventors in the field, and should be construed as not being specifically mentioned. Limitations of examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof,

Claims

Rights request

1 : A handover method in a cell covered by a base station in which one or more relay nodes are deployed, comprising: configuring information about a random access channel PRACH signal transmission required by the one or more relay nodes; Requesting a user equipment located at a cell edge location to perform PRACH transmission;

The one or more relay nodes detect related information of PRACH transmission from the user equipment, and send a detection report to the base station;

Based on the transmitted detection reports of one or more relay nodes, the base station selects a suitable relay node to serve the user equipment and sends a notification to the user equipment.

2. The method according to claim 1, further comprising: estimating whether the user equipment is located at a location of a cell edge, wherein the user is estimated when a downlink measurement report sent by the user equipment to the base station is lower than a first predetermined threshold within a predetermined time The device is located at the edge of the cell.

3. The method according to claim 1, further comprising: estimating whether the user equipment is located at a location of a cell edge, wherein when the uplink reception quality of the base station is lower than a second predetermined threshold within a predetermined time, estimating that the user equipment is located in the cell edge.

4. The method according to claim 2 or 3, the step of estimating whether the user equipment is located at a cell edge further comprises: when receiving a report from the relay node, the report indicating the predetermined time When the uplink UL reception quality of the relay node is lower than a third predetermined threshold, it is estimated that the user equipment moves out of the coverage area of the relay node.

The method according to claim 2 or 3, the step of estimating whether the user equipment is located at a cell edge further comprises: receiving an uplink UL reception quality from the relay node that is lower than the first time when the predetermined time is received When the threshold is predetermined, the user equipment is estimated to move out of the coverage area of the relay node.

6. The method of claim 4, further comprising: requesting the relay node to perform a release process.

7. The method of claim 5, further comprising: requesting the relay node to perform a release process.

8. The method of claim 1, wherein the notification sent to the user equipment comprises: a TA command including a timing advance TA information associated with the selected relay node, calculated by the base station based on the report of the selected relay node.

9. A base station capable of performing handover in a cell covered by a base station in which one or more relay nodes are deployed, comprising:

a configuration device, configured to configure a random access channel PRACH letter required by the one or more relay nodes Information transmitted by the number; a requesting device, configured to request a user equipment located at a cell edge location to perform PRACH transmission;

a receiving device, configured to receive, by the one or more relay nodes, a detection report about related information of a PRACH transmission of the user equipment, where the one or more relay nodes detect related information of PRACH transmission from the user equipment ;

Selecting means, based on the detection report, selecting a suitable relay node to serve the user equipment; and transmitting means to send a notification to the user equipment.

10. The base station according to claim 9, further comprising: estimating means, configured to estimate whether the user equipment is located at a cell edge, wherein a downlink measurement report sent by the user equipment to the base station is lower than the first reservation within a predetermined time At the threshold, the estimating device estimates that the user equipment is located at the cell edge.

11. The base station according to claim 9, further comprising: estimating means, configured to estimate whether the user equipment is located at a location of a cell edge, wherein when the uplink reception quality of the base station is lower than a second predetermined threshold within a predetermined time, the estimation The user equipment is located at the edge of the cell.

The base station according to claim 10 or 11, wherein the estimating means estimates, according to a report from the relay node, that the user equipment moves out of the coverage area of the relay node, and the report indicates that the predetermined time The uplink UL reception quality of the secondary node is below a third predetermined threshold.

The base station according to claim 10 or 11, wherein the estimating device estimates the user equipment removal station when the uplink UL reception quality received from the relay node received in the predetermined time is lower than a fourth predetermined threshold The coverage area of the relay node.

The base station according to claim 12, wherein the requesting device is further configured to request the relay node to perform a release process.

The base station according to claim 13, wherein the requesting device is further configured to request the relay node to perform a release process.

16. The base station according to claim 9, further comprising: computing means for calculating a timing advance TA information associated with the selected relay node based on the report of the selected relay node.

17. The base station according to claim 16, wherein the notification comprises: a TA command including the timing advance TA information. ·

18. A relay node capable of performing handover in a cell in which one or more relay nodes are deployed, comprising: receiving means for receiving a transmission of a random access channel PRACH signal from a user equipment; A signal for detecting a random access channel PRACH signal transmission required by the relay node Information about the PRACH transmission from the user equipment;

And a sending device, configured to send, to the base station, a detection report about the related information of the PRACH transmission of the user equipment, so that the base station selects a suitable relay node to serve the user equipment based on the detection report from the one or more relay nodes .

19. The relay node according to claim 18, further comprising comparing means for comparing an uplink UL reception quality of the relay node with a predetermined threshold, and the UL reception quality is lower than the predetermined time within a predetermined time At the threshold, a report indicating that the UL reception quality of the relay node is lower than a predetermined threshold within a predetermined time is transmitted by the transmitting device.

20. The relay node according to claim 18, wherein the transmitting device is further configured to send a UL reception quality of the relay node to a base station.

A communication system capable of performing handover in a cell in which one or more relay nodes are deployed, comprising the base station according to claim 9, one or more relay nodes according to claim 18, and User equipment.